Fastener insertion device

Abstract

A computer-based implementation method for determining the properties of a fastener. The method includes the step of receiving a stored deflection coefficient, the stored deflection coefficient relating the deflection of the fastener setting tool to the peak force exerted on the die by the fastener. The method further includes the step of receiving a determined peak force, the determined peak force corresponding to the peak force exerted on the fastener by the punch of the fastener setting tool. The method further includes the steps of receiving a determined thickness of the workpiece, receiving a determined position of the upper end face of the fastener, and determining the head height of the fastener.

Description

Technical Field

[0001] (Technical Field) The present invention relates to a computer-implemented method for determining the characteristics of fasteners, and a computer-implemented method for determining the characteristics of workpieces and / or fastener set tools.

Background Art

[0002] (Background Art) Fasteners, such as self-piercing rivets, may be inserted into a workpiece to mechanically fix together the panels of the workpiece. Self-piercing rivets may also be referred to as self-inserting rivets. The workpiece may comprise two or more panels. The workpiece may further comprise an interlayer material (e.g., an adhesive, a sealant and / or a foil) provided between two adjacent panels. As an example, the workpiece may comprise an aluminum panel that may form part of an automobile or another vehicle.

[0003] The fastener may be inserted using a fastener set tool. The fastener set tool typically drives the fastener into the workpiece while the workpiece is supported by a die. In the case of a self-piercing rivet, the self-piercing rivet may expand radially outwards in order to be able to fix together the panels of the workpiece. The surface of the die supporting the workpiece may be provided with a shape that facilitates the expansion of the self-piercing rivet.

[0004] Similar workpieces may not be identical. For example, workpieces from a single batch corresponding to a portion of a product may vary by different amounts from the nominal workpiece. In other words, the thickness of a nominal workpiece may be known, but the thickness of each individual workpiece may not be known unless each workpiece is measured separately. Other properties, such as the strength or ductility of a workpiece, may not be known unless each workpiece is measured separately. Measuring each component of each workpiece separately (i.e., each panel and optionally each interlayer material) or each workpiece separately may add an additional step to the construction process, and therefore may slow down the construction process.

[0005] Fasteners may be inserted into a workpiece at a predetermined speed and force to achieve the required insertion depth. After insertion into the workpiece surface, the head height of the fastener (i.e., the position of the upper surface of the fastener relative to the upper surface of the workpiece in the area close to the fastener) may indicate the characteristics of the joint made by the fastener. Without destructive testing, head height may be the only indicator of the strength of the joint. Measuring head height in conventional manner may add one or more extra steps to the construction process and thus may slow down the construction process.

[0006] When using an inertial fastener set tool, the amount of energy available to the fastener includes contributions from the flywheel's inertia, the tool's linear momentum, and the torque provided by the motor. The amount of energy available to be supplied to the fastener can be reduced by frictional losses within the tool. Frictional losses can vary depending on the condition of the tool. These conditions may include, for example, temperature, age, fastener characteristics, workpiece characteristics, previous tool use, and lubrication characteristics (e.g., lubrication amount, lubrication temperature).

[0007] A tool may be in a "low temperature" state. A tool can be low temperature if its temperature is below the desired operating temperature. A tool may also be low temperature if no recent insertion cycles have been performed. When a tool is in a low temperature state, internal friction may increase, for example, due to the lubrication being below its optimal temperature (i.e., low temperature) and / or due to other factors such as the tool being used with new, worn, or damaged parts / components.

[0008] Alternatively, the tool may be in a "warm" state. A tool may be warm when it is at its desired operating temperature. Recently, for example, if a sufficient insertion cycle has been performed within the last 15 minutes, the tool may be warm. When the tool is warm, internal friction may decrease, for example, due to the lubrication being at its optimal temperature (i.e., warm) and / or due to other factors such as the tool being used with new, unworn, or undamaged parts / components.

[0009] Alternatively, the tool may be "warm." A warm tool is between a "low temperature" and a "warm temperature," and its operating temperature may be elevated. Low-temperature and / or warm tools may experience greater internal friction compared to warm tools. This increased internal friction can be due to changes in lubrication viscosity and / or the movement and position of lubrication within the tool, as well as changes in the state of internal components. Therefore, operating a warm tool is beneficial because it requires less driving force compared to a low-temperature or warm tool. However, for example, when a tool is first used, it may be necessary to use a low-temperature or warm tool. In such cases, compensating for friction loss may be beneficial.

[0010] When a tool is riveting a workpiece (or certain types of workpieces) for the first time, the parameters (e.g., force) to be used by the tool are often selected by the engineer operating the tool. For example, the parameters may be selected based on the engineer's experience. The parameters may be input to the tool using a human-machine interface (HMI). The parameters may not be optimal. For example, more or less force (than the force selected by the engineer) may be required for a particular workpiece to obtain a joint with the desired properties. Despite the use of excessive force, the joint formed by the tool in the workpiece may appear satisfactory. That is, the die may hold the expected volume of the workpiece, the panel gap may be closed, and the fastener head may be flush. However, such a joint may have been formed using more force than necessary. Using such excessive force may shorten the lifespan of the tool and its components. For example, the punch and / or blank holder may suffer excessive wear due to the use of excessive force.

[0011] It is unlikely that excessive force will be detected when an engineer operates a tool. This can be true regardless of the setter technique or method used to apply force (i.e., whether a hydraulic, electric, or pneumatic-hydraulic system is used). This is because more force can be applied without changing the resulting head height at the point when the die is filled and the fastener head height is flush. In other words, the head height of a fastener after the tool has applied the optimal amount of force may be the same as the head height of a fastener after the tool has applied an excessive amount of force. While force has been discussed as an example of a parameter, similar considerations apply to other examples such as the energy applied by the tool or the speed at which the tool is operated.

[0012] The objective of the present invention is to overcome or mitigate one or more of these problems. [Overview of the project]

[0013] (Summary of the invention) A first example described herein is a computer-based method for determining the properties of a fastener, the method comprising the steps of: receiving a stored deflection coefficient, the stored deflection coefficient relating the deflection of the fastener setting tool to the peak force exerted on the die by the fastener; receiving a determined peak force, the determined peak force corresponding to the peak force exerted on the fastener by the punch of the fastener setting tool; receiving a determined thickness of the workpiece; receiving a determined position of the upper end face of the fastener; and determining the head height HH of the fastener as follows:

number

[0014] Beneficially, the method may allow for the determination of the fastener head height without measuring the head height itself. The fastener head height may indicate a characteristic of the workpiece. Head height may also be referred to as the position of the upper surface of the fastener head relative to the upper surface of the workpiece in the region close to the fastener. The region close to the fastener may directly surround the fastener or may extend beyond the region deformed due to the insertion of the fastener.

[0015] The determined head height of a fastener may, in lieu of (or in addition to) destructive testing, indicate the strength (or other characteristic) of the joint (i.e., the joint formed by the fastener). For example, the head height of a first joint in a first workpiece may be determined, and the strength of the first joint may be determined using destructive testing. The head height of a second joint in a second workpiece may be determined and used to estimate the strength of the second joint based on the head height and strength of the first joint.

[0016] The fasteners may be rivets, such as self-piercing rivets. The blank holder may also be called a workpiece holder or nose. The die may be configured to prevent the workpiece from moving under force applied to it. The die may also be called an anvil.

[0017] The position of the upper end face of the fastener may be determined by measurement using a first sensor, a second sensor, or an encoder. For example, the punch speed as a function of time may be recorded and used to determine the maximum displacement of the punch, and the determined maximum displacement of the punch may be used to determine the position of the upper end face of the fastener.

[0018] Determining the peak force exerted on the fastener by the punch may involve the use of a force sensor, such as a force sensor provided on the punch. Alternatively, the force may be determined using an encoder to measure the motor torque applied to the punch.

[0019] The upper end face of the fastener may be the surface of the fastener that faces and / or contacts the punch. The upper end face of the fastener may be the surface of the fastener closest to the blank holder when the blank holder is in the retracted position.

[0020] The deflection of a fastener set tool may be the deflection of the die from a first position to a second position due to the force exerted by the fastener set tool. The deflection coefficient may be related to the position of the fastener in the workpiece and / or similar workpieces. In other words, different deflection coefficients may be obtained when fasteners are inserted at different positions in the workpiece. The same deflection coefficient may be obtained when fasteners are inserted at similar positions in similar workpieces. Alternatively, the deflection coefficient may be consistent across the workpiece and / or similar workpieces.

[0021] The step of receiving the determined thickness of the workpiece may further include: advancing the blank holder of the fastener set tool so that the blank holder moves to a calibration position; measuring the position of the calibration position along the axis moved by the blank holder using a first sensor configured to measure the displacement of the blank holder; advancing the blank holder so that the blank holder contacts the surface of the workpiece and clamps the workpiece against the die; measuring the position of the surface of the workpiece along the axis moved by the blank holder using the first sensor; and determining the thickness of the workpiece using the measured position of the calibration position and the measured position of the surface of the workpiece.

[0022] Preferably, the use of a calibration position can improve the accuracy of the measurement.

[0023] The calibration position may be the position of the blank holder when it contacts the surface of the die. In other words, the calibration position may be a first position on the die, and / or the measurement position of the calibration position may be a first measured position on the surface of the die. Alternatively, the calibration position may be the position of the blank holder when it contacts the surface of a calibration member placed on the die. For example, the calibration member may be a nominal workpiece and / or have the same width as the expected width of the workpiece.

[0024] The method may further include the step of retracting the blank holder so that the workpiece can be inserted between the blank holder and the die.

[0025] When the blank holder contacts the surface of the workpiece, the blank holder may clamp the workpiece against the die.

[0026] The measured position of the calibration position may be represented as the distance by which the blank holder is moved by the blank holder to move to the calibration position. Similarly, the measured position of the surface of the workpiece may be represented as the distance by which the blank holder is moved by the blank holder to contact the surface of the workpiece.

[0027] The determined thickness of the workpiece may be determined with respect to the calibration position. In an example where the calibration position is the first position of the die, the determined thickness of the workpiece may be the thickness of the workpiece (i.e., the absolute thickness). For example, the workpiece may be determined to have a thickness of 5.6 mm. In an example where the calibration position is the position of the blank holder when the blank holder contacts the surface of the calibration member, the determined thickness of the workpiece may be determined with respect to the thickness of the calibration member (i.e., the relative thickness). For example, the determined thickness may be 1 mm thicker than the thickness of the calibration member.

[0028] The determined position of the upper end surface of the fastener may be determined with respect to the calibration position. In an example where the calibration position is the surface of the die, the determined position of the upper end surface of the fastener may be determined with respect to the measured position of the surface of the die.

[0029] The method may further include the steps of receiving the thickness of a calibration member and determining the absolute thickness of the workpiece using the determined thickness of the workpiece relative to the thickness of the calibration member. In other words, the absolute thickness may be determined from the relative thickness. For example, the determined thickness relative to the calibration member may be 1 mm (i.e., 1 mm thicker than the calibration member), a calibration member thickness of 4.6 mm may be received, and the absolute thickness of the workpiece may be determined to be 5.6 mm.

[0030] The method may further include the step of applying a threshold test to the determined head height.

[0031] A binary result may be given from the threshold test. For example, the threshold test may be 5 mm (or less), the determined head height may be 5.6 mm, and the threshold test may give a result of 0 to indicate that the threshold test failed. Alternatively, for a determined head height of 4.6 mm, the same threshold test may give a result of 1 to indicate that the threshold test passed. Alternatively, the threshold test may test whether the determined head height is greater than or equal to the threshold, or greater than or equal to the threshold, or less than or equal to the threshold. The result of the threshold test may be expressed as a warning indicator and / or a fault indicator.

[0032] The method may include the step of applying a threshold test or a set of threshold tests to a determined head height. In other words, the threshold test may be one of several threshold tests. Each test may correspond to a different condition.

[0033] A second example described herein is a computer-implemented method for determining the properties of a workpiece and / or a fastener set tool, the method comprising: advancing a blank holder of a fastener set tool so that the blank holder moves to a calibration position; measuring the position of the calibration position along the axis moved by the blank holder using a first sensor configured to measure the displacement of the blank holder; advancing the blank holder so that the blank holder contacts the surface of a workpiece and clamps the workpiece against a die; measuring the position of the surface of the workpiece using the first sensor; and determining the thickness of the workpiece using the measured position of the calibration position and the measured position of the surface of the workpiece.

[0034] The characteristics of the workpiece may include the characteristics of the joints formed on the workpiece.

[0035] Similar to the first example, the method may further include the step of applying a threshold test to a determined thickness of the workpiece. The method may further include the steps of determining, based on the results of the threshold test, that the fastener set tool requires maintenance; determining, based on the results of the threshold test, that the workpiece should be inspected and / or replaced; and / or determining, based on the results of the threshold test, that parameters associated with the fastener set tool should be adjusted.

[0036] The method may further include the step of retracting the blank holder so that the workpiece can be inserted between the blank holder and the die.

[0037] The method involves the steps of receiving a determined position of the upper end face of the fastener, receiving a measured head height of the fastener, and determining the tool deflection TD corresponding to the change in the end position relative to the starting position of the tool components due to the insertion of the fastener, as follows:

number

[0038] The measured head height may be measured manually by the operator of the fastener set tool, for example, using a dial test indicator. The fastener may be one that is inserted into the workpiece.

[0039] The method may further include the step of storing the determined tool deflection. For example, the tool deflection may be stored in computer-readable memory. The method involves determining the peak force exerted on the fastener by the punch, and determining the deflection coefficient DF corresponding to the deflection of the fastener set tool in response to the peak force exerted on the fastener by the punch, as follows:

number

[0040] Beneficial in this regard, the deflection coefficient can allow for the determination of the head height of a fastener without having to measure the head height itself.

[0041] The deflection coefficient and / or tool deflection may depend on the location of the joint (i.e., the joint formed by fasteners in a workpiece). In other words, the deflection coefficient and / or tool deflection may be determined with respect to the location of the joint. If the properties of the joint are changed (e.g., the location, workpiece, or fasteners are changed), a new deflection coefficient and / or tool deflection may be determined. The location of the joint may apply to a single workpiece or multiple workpieces having joints at corresponding locations.

[0042] The method may further include the step of storing the deflection coefficient. For example, the deflection coefficient may be stored in computer-readable memory.

[0043] The method may further include the step of applying threshold tests to the determined properties. For example, threshold tests may be applied to the deflection coefficient, tool deflection, and workpiece thickness.

[0044] A third example described herein is a computer-implemented method for determining the properties of a workpiece or a joint formed on a workpiece, the method comprising the steps of: bringing a blank holder of a fastener set tool into contact with the surface of a workpiece; applying a force to the blank holder in the axial direction toward the workpiece; detecting the movement of the workpiece by measuring the displacement of the blank holder; and determining the properties of the workpiece or a joint formed on the workpiece based on the detected movement.

[0045] The method may further include the step of determining that the detected movement has a predetermined characteristic. The predetermined characteristic may include, for example, consistent movement of a workpiece panel in a single direction. In other words, two or more panels of a workpiece may move together gradually under a force applied by the blank holder, i.e., two or more panels may be compressed together. The predetermined characteristic may include, for example, vibration of one or more panels. In other words, one or more panels may move back and forth in response to a perturbation given by a force applied by the blank holder.

[0046] The movement of the workpiece may be in response to a force applied by the blank holder. Additionally or alternatively, the movement of the workpiece may be in response to the insertion of the fastener by a punch of the fastener set tool.

[0047] Detection that two or more panels are being compressed together may indicate that a gap existed between the panels in the workpiece before they were compressed together. Additionally or alternatively, detection that two or more panels are being compressed together may indicate the presence and / or amount of adhesive present.

[0048] Vibration detection may indicate brittleness of the workpiece panel.

[0049] The characteristics of the workpiece may be the characteristics of the workpiece's panels, for example, the top panel. In other words, the characteristics may be those of the panel closest to the blank holder.

[0050] The method may further include the step of applying a threshold test to the determined characteristics.

[0051] Either method may further include the step of inserting a fastener into the workpiece using a punch of a fastener set tool. In other words, the fastener may form a joint in the workpiece. The fastener may be a first fastener. It can be understood that the insertion may be successful or unsuccessful. Furthermore, the fastener may be fully inserted or partially inserted after insertion.

[0052] The characteristic may be distortion of the workpiece (or a panel within the workpiece).

[0053] Either method may further include a step of determining, based on the results of a threshold test, that the fastener set tool requires maintenance.

[0054] Either method may further include a step of informing the user that maintenance is required, and / or the method may further include performing maintenance. The method may further include a step of determining, based on the results of a threshold test, that the fastener set tool does not require maintenance.

[0055] In an example where the method includes multiple threshold tests, the steps of determining whether the fastener set tool requires maintenance and / or whether the fastener set tool does not require maintenance may be based on the results of one or more of the multiple threshold tests. The method may further include steps of indicating that maintenance is required, scheduling maintenance, and / or having the maintenance performed.

[0056] Either method may further include a step of determining, based on the results of a threshold test, that the workpiece should be replaced.

[0057] In other words, the method may identify that a workpiece is unsuitable for use in a process and / or product. For example, a workpiece may be too brittle, too ductile, too thick, too thin, and / or too hard for its intended use. The method may further include the steps of indicating that the workpiece should be replaced and / or causing the workpiece to be replaced.

[0058] One of the methods may further include a step of determining, based on the results of a threshold test, that parameters associated with the fastener set tool should be adjusted.

[0059] In other words, the method may identify that a joint (i.e., a joint formed by a fastener on a workpiece) can be improved by changing parameters associated with a fastener setting tool. For example, the force applied to the fastener by the punch and / or the speed of the punch may be adjusted. The method may further include indicating that a parameter should be adjusted and / or causing the parameter to be adjusted. The parameter may be adjusted so that the fastener setting tool uses the adjusted parameter to insert the fastener (i.e., to continue / complete the insertion of the fastener). Additionally or alternatively, the parameter may be adjusted so that the fastener setting tool uses the adjusted parameter to insert subsequent fasteners into the same workpiece and / or subsequent workpieces. As an example of a parameter that may be adjusted, the type of rivet being inserted may be changed.

[0060] Measuring the displacement of a blank holder may include measuring the displacement of a component of a fastener set tool fixed to the blank holder. Such a method allows for the measurement of the blank holder's displacement without directly measuring the blank holder's position. Therefore, there is no need to place a sensor in the vicinity of the blank holder. Preferably, by measuring the blank holder's position relative to the calibration position, the length of the component required to measure the blank holder's displacement can be reduced. Beneficially, this can also reduce the space occupied by the blank holder, thereby improving access to the workpiece in an industrial production environment. Beneficially, by not needing to place a sensor in the vicinity of the blank holder, the sensor can be kept away from a larger area of ​​exposure to debris, dust, and / or damage, thus improving the sensor's potential lifespan and reducing the need for service. For example, measuring the position of the calibration position may include measuring a first position of the component (i.e., the position of the component when the blank holder is in the calibration position). As another example, measuring the position on the surface of a workpiece may include measuring a second position of the component (i.e., the position of the component when the blank holder is in contact with the surface of the workpiece).

[0061] Any of the methods in the preceding examples may further include the steps of: comparing a determined characteristic with a predetermined characteristic, where the difference between the determined characteristic and the predetermined characteristic represents the state of the fastener set tool or workpiece; calculating an adjustment based on the comparison to compensate for the state of the fastener set tool or workpiece; and applying the adjustment to the fastener set tool and / or workpiece.

[0062] The performance of a fastener set tool can vary depending on the condition of the tool, for example, whether the tool is cold, warm, or hot. By using this method, various aspects of the tool's performance can be compensated for. In particular, the effect of friction loss can be indirectly determined by measuring a first parameter and comparing it to a predetermined parameter. Therefore, a compensation method is provided by calculating and applying adjustments. Such a compensation method can beneficially improve the performance of the tool.

[0063] The energy consumption and / or wear rate of a fastener set tool may vary depending on the condition of the tool, for example, according to the target parameters set for the tool. Exemplary target parameters may include force and / or energy. As previously mentioned, once sufficient force has been applied to the tool to fill the die, applying additional (i.e., excessive) force will not change the head height. By using this method, the optimal head height can be achieved with minimal force and / or energy consumption. Such a compensation method can beneficially save energy and improve the lifespan of the tool and its components.

[0064] The determined characteristic may be, for example, the determined head height of the first fastener. Alternatively, the characteristic may be the coefficient of deflection.

[0065] The predetermined characteristics may be determined at an earlier stage. For example, the predetermined characteristics may be loaded from a database. Alternatively, the predetermined characteristics may be determined based on the previous fastener insertion.

[0066] The condition of the fastener set tool may include, or may include, temperature, age, previous use of the tool, and lubrication characteristics (e.g., lubrication amount, lubrication temperature). The condition of the workpiece may include, or may include, the strength, ductility, or properties of the fastener.

[0067] The method may be performed iteratively to form a feedback loop. The steps of comparing, calculating, and applying adjustments may be repeated any number of times with respect to the same or consecutive fasteners. In this way, the method may converge on parameters for inserting fasteners in such a way that it helps minimize tool wear while ensuring that the fasteners are inserted according to predetermined characteristics.

[0068] In some examples, the adjustment may be applied automatically; that is, the fastener set tool may apply the adjustment without any further input. In other examples, the method may further include a step of outputting an indication of the adjustment at the output of the fastener set tool. The method may further include a step of receiving a user input at the input of the fastener set tool instructing the fastener set tool to apply the adjustment, and the adjustment may be applied in response to the user input.

[0069] The determined characteristics may be based on multiple measurements. For example, the determined characteristics may be the average of determined head heights, where each determined head height corresponds to a different fastener.

[0070] The steps of comparing the determined characteristics with predetermined characteristics, calculating adjustments based on the comparison, and applying the adjustments may each be performed after the punch has inserted the first fastener into the workpiece. The method may further include the step of inserting the second fastener into the workpiece into the punch after the adjustments have been applied. In other words, the fastener setting tool may insert the first fastener with a first set of parameters, and based on the comparison, insert the second fastener with a second set of parameters. Additionally or alternatively, the method may further include the step of further inserting the first fastener into the workpiece into the punch after the adjustments have been applied. In other words, the fastener setting tool may insert the first fastener with a first set of parameters, and based on the comparison, further insert the first fastener with a second set of parameters. In other words, the adjustments may be applied while the first fastener is inserted.

[0071] The adjustment may be an adjustment to the torque and / or force applied by the fastener setting tool. For example, the head height of the first fastener may be greater than the required head height. In response, the fastener setting tool may apply higher torque and / or force when further inserting the first fastener and / or the second fastener. Alternatively, the head height of the first fastener may be lower than the required head height. In response, the fastener setting tool may apply less torque and / or force when inserting the second fastener. The motor torque may correspond to the motor speed or the electrical stimulation applied to the motor.

[0072] The adjustment may be an adjustment to the speed of the fastener setting tool. For example, the speed may be the target speed at which the punch of the fastener setting tool operates. Thus, the fastener insertion tool may insert fasteners at an optimal speed. The optimal speed may be the fastest speed that results in accurately inserted fasteners (i.e., without any over-insertion). Beneficially, such an adjustment may allow the manufacturing process to be sped up.

[0073] In some examples, the punch of a fastener set tool may be configured to operate at a first speed while in a first region and at a second speed while in a second region. In particular, the punch may operate at a higher speed when in the first region, further away from the fastener to be inserted, and at a lower speed when in the second region, closer to the fastener. In other words, the punch may operate in a fly across space velocity. In such examples, the adjustment may be for the first speed and / or the second speed.

[0074] Any of the methods in the preceding examples may further include the steps of comparing a determined characteristic with a predetermined characteristic, where the difference between the determined characteristic and the predetermined characteristic represents the state of the fastener set tool and / or workpiece, and determining, based on the comparison, that no adjustment to the fastener set tool and / or workpiece is required.

[0075] The determined characteristic may be the determined head height of the first fastener, and the predetermined characteristic may be the predetermined head height.

[0076] The determined properties may be the determined thickness of the workpiece, and the predetermined properties may be the predetermined thickness.

[0077] The determined characteristic may be a determined tool deflection, and the predetermined characteristic may be a predetermined tool deflection.

[0078] The determined characteristic may be the determined deflection coefficient, and the predetermined characteristic is the predetermined deflection coefficient. A fourth example described herein provides a computer-implemented method for determining the force required to insert a fastener into a workpiece using a fastener setting tool, the method comprising the steps of receiving the required head height of the fastener, receiving the thickness of the workpiece, receiving the deflection coefficient, receiving the desired position of the upper end face of the fastener, and determining the force PF to be applied to the fastener by the punch of the fastener setting tool as follows:

number

[0079] The method may further include the step of inserting the fastener into the workpiece using a fastener set tool with a determined force.

[0080] A fifth example described herein is a fastener set tool configured for use in any of the preceding examples.

[0081] In the sixth example described herein, there is a controller for a fastener set tool, which is configured to perform one of the methods of the first to fifth examples.

[0082] A seventh example described herein includes a fastening tool set comprising a first sensor configured to measure the displacement of a blank holder.

[0083] The fastening tool set may further include a member fixed to the blank holder. The first sensor may be configured to measure the displacement of the member.

[0084] The first sensor may be a contact-type displacement sensor.

[0085] Hereinafter, references to receiving a quantity, determining a quantity, or measuring a quantity will be interpreted similarly. For example, receiving a determined position of the upper end face of a fastener may include determining the position of the upper end face of a fastener and / or measuring the position of the upper end face of a fastener.

[0086] It is also understood that the steps of any method can be performed in any suitable order. For example, in the method of the first example, the position of the workpiece surface may be received before the position of the calibration position is received.

[0087] Herein, embodiments of the present invention will be described merely as examples with reference to the following drawings. [Brief explanation of the drawing]

[0088] (Brief explanation of the drawing) [Figure 1] This is a side view of an example of a rivet set tool. [Figure 2] This is a flowchart illustrating the method for determining the thickness of a workpiece. [Figure 3A] A schematic diagram shows a system equipped with a rivet setting tool during the process of determining the thickness of a workpiece. [Figure 3B] A schematic diagram shows a system equipped with a rivet setting tool during the process of determining the thickness of a workpiece. [Figure 3C] A schematic diagram shows a system equipped with a rivet setting tool during the process of determining the thickness of a workpiece. [Figure 3D] A schematic diagram shows a system equipped with a rivet setting tool during the process of determining the thickness of a workpiece. [Figure 3E] A schematic diagram shows a system equipped with a rivet setting tool during the process of determining the thickness of a workpiece. [Figure 3F] A schematic diagram shows a system equipped with a rivet setting tool during the process of determining the thickness of a workpiece. [Figure 4] This is a flowchart illustrating the method for determining tool deflection. [Figure 5] This is a flowchart showing a method for determining the head height of a fastener. [Figure 6] This is a flowchart showing how to determine the force required to insert a fastener. [Figure 7] This is a flowchart illustrating a method for determining the characteristics of a workpiece or a joint formed on a workpiece. [Figure 8] This flowchart shows how to calculate and apply adjustments to fastener sets, tools, and / or workpieces. [Figure 9] This flowchart shows how to determine if adjustments are necessary to the fastener set tool and / or workpiece. [Figure 10] This flowchart illustrates an iterative method for calculating and applying adjustments to fastener sets, tools, and / or workpieces. [Figure 11] This document shows an exemplary computer system that may be used to perform the actions described herein. [Modes for carrying out the invention]

[0089] (Modes for carrying out the invention) Figure 1 shows a side view of the rivet insertion tool 2. The rivet insertion tool 2 (also called a fastener set tool or rivet set tool) is mounted on the upper arm of a conventional C-frame 4. The die 6 is mounted on the lower arm of the C-frame 4 using associated mounting components (e.g., a die holder). The die 6 is sometimes called an anvil. The workpiece W into which the self-piercing rivets are inserted is located between the blank holder 14 and the die 6. The rivet set tool 2 includes a motor 8 connected to the actuator 12 via a transmission device 10 (all of which are located in their respective housings). The rivet set tool 2 further includes a blank holder 14 fixed to the end of the actuator 12. The blank holder 14 may also be called a nose. Part of the blank holder 14 is a hollow cylinder from which a punch (not shown) extends to allow the self-piercing rivets to be inserted into the workpiece W. The self-piercing rivets may be provided on a tape of self-piercing rivets supplied to part of the rivet set tool 2. An alternative device can be provided for supplying self-piercing rivets. For example, a single rivet supply system can transport self-piercing rivets from a hopper using a pneumatic system.

[0090] The workpiece W may comprise multiple panels. The panels may be made of, for example, aluminum (e.g., cast aluminum or extruded aluminum), steel (e.g., high-strength steel), or magnesium. The apparatus (e.g., rivet insertion tool 2) and method described herein may be particularly useful for use with materials with low tolerances, such as cast aluminum or extruded aluminum. The panels may form part of an automobile or another vehicle.

[0091] The workpiece W may further include interlayer materials (e.g., adhesives, sealants, and / or foils) as needed. For example, a layer of adhesive can be provided between two adjacent panels to provide an additional means of fastening the two adjacent panels together.

[0092] The rivet insertion tool 2 may be provided with a blank holder displacement sensor. The blank holder displacement sensor may also be called a means for measuring the displacement of the blank holder 14. For example, the blank holder displacement sensor may be a sensor for measuring the distance the blank holder 14 has moved. The displacement of the blank holder 14 can be measured with respect to a point on the rivet insertion tool 2 (i.e., a fixed point) that is not expected to move while the rivet is being inserted. The fixed point may be, for example, a point on the actuator 12 or a point on the C-frame 4. The blank holder displacement sensor may be any suitable sensor for measuring the displacement of the blank holder 14. The blank holder displacement sensor may comprise, for example, a contact displacement sensor 20 (shown in Figure 1). The blank holder displacement sensor may comprise a light source and light sensor, an accelerometer, an inductance sensor, an optical sensor, and / or any other sensor known in the art.

[0093] In an example where the blank holder displacement sensor includes a contact displacement sensor 20, the contact displacement sensor 20 may include a plunger 22 and a sensor body 24. The plunger 22 may be rigid. In the initial position, the plunger 22 may extend outside the sensor body 24, or it may be positioned inside the sensor body 24 such that the surface of the end of the plunger 22 is coplanar with the surface of the sensor body 24. The plunger 22 may be integrated with the dust boot of the contact displacement sensor 20. The contact displacement sensor 20 may include a biasing member for returning the plunger 22 to its initial position after it has been displaced. The sensor body 24 may include one or more sensors for determining the displacement of the plunger 22 from its initial position. For example, the plunger 22 may be pushed inward (i.e., more of the plunger 22 is inside the sensor body 24 than when it is in the initial position, and / or the surface of the end of the plunger 22 is inside the sensor body 24), and the displacement of the plunger 22 can be measured by one or more sensors. When the plunger 22 can no longer be pushed inward, the biasing member can return the plunger 22 to its initial position. The sensor body 24 of the contact displacement sensor 20 may be fixed to the blank holder 14. The surface of the plunger 22 configured to contact the object being measured by the contact displacement sensor 20 may be called the contact surface. The plunger 22 may be axially aligned with the movement of the blank holder 14. Additional components may be provided to fix the sensor body 24 to the blank holder 14 so that the sensor body 24 is not directly fixed to the blank holder 14 (but the sensor body 24 and the blank holder 14 are fixed to each other). The rivet insertion tool 2 may include a member 30 fixed to a fixing point. The member 30 may be rigid and have a striking surface; for example, the member 30 may be a rod. The member 30 may be rigid. For example, the member 30 may be fixed to the actuator 12. The member 30 may be aligned axially with the movement of the blank holder 14 and positioned in contact with the end of the plunger 22 (i.e., the contact surface of the contact displacement sensor).In other words, the end surface of the plunger 22 comes into contact with the striking surface of the member 30, thereby enabling the contact displacement sensor 20 to measure the displacement of the member 30.

[0094] The contact displacement sensor 20 and member 30 can indirectly measure the position of the blank holder 14. In other words, by measuring the displacement of the contact displacement sensor 20 relative to member 30, the displacement of the blank holder 14 can be estimated. For example, by measuring the first position of the contact displacement sensor 20 relative to member 30 when the blank holder 14 is in a first position, and the second position of the contact displacement sensor 20 relative to member 30 when the blank holder 14 is in a second position, the distance between the first and second positions of the blank holder 14 can be determined.

[0095] Although the sensor body 24 has been described as being fixed to the blank holder 14 and the member 30 fixed to the actuator 12, the rivet insertion tool 2 (and its components) may be arranged in any suitable manner. For example, in an alternative arrangement, the contact displacement sensor 20 may be fixed to the actuator 12, and the member 30 may be fixed to the blank holder 14. Other configurations that enable the measurement of the position of the blank holder 14 will be obvious to those skilled in the art.

[0096] As mentioned above, the blank holder displacement sensor may include an inductance sensor. For example, the plunger 22 may include a magnet. The sensor body 24 may include a detection coil and a generating coil. The coils may be arranged coaxially, with one located inside the other. The detection coil can measure the magnetic field generated by the flow of charge through the generating coil. The presence of a magnet in the detection coil and / or generating coil can change the impedance, and therefore the magnetic field being measured. Thus, by measuring the magnetic field, the displacement of the magnet can be measured by the blank holder displacement sensor.

[0097] As mentioned above, the blank holder displacement sensor may also include an optical sensor. For example, the plunger 22 may have a scale. The sensor body 24 may also have an optical sensor. The optical sensor may be a CMOS sensor. The blank holder displacement sensor may be configured to determine the displacement of the plunger based on data from the optical sensor. The scale may be linear, or it may be nonlinear. For example, the scale may include a complex pattern that allows for more accurate measurement of the plunger displacement. Part of the scale may be at least partially translucent. For example, the display of the scale may be provided on the glass portion. The light source may also be provided within the blank holder displacement sensor. For example, when used with a scale that is at least partially transparent, the light source may be provided on the opposite side of the scale from the optical sensor. In this way, the portion of the scale facing the optical sensor can be determined by the contact displacement sensor 20, thereby allowing the displacement of the plunger 22 to be measured.

[0098] As mentioned above, the blank holder displacement sensor may also include a light source and an optical sensor. The light source may be, for example, a laser. The light source may be fixed to a fixed point, and the light source may be provided on the blank holder 14. Alternatively, the light source and optical sensor may be fixed to a fixed point, and a portion that reflects light may be provided on the blank holder 14. In other words, one or more reflective surfaces (e.g., mirrors and / or prisms) may be provided on a part of the blank holder 14. The optical sensor or reflective surface may be provided on a projection extending from the blank holder 14. For example, the optical sensor or reflective surface may be fixed to the blank holder 14 so that the optical sensor or reflective surface moves with the movement of the blank holder 14. The light source, optical sensor, and reflective surface may be configured so that light (emitted by the light source) is detected by the optical sensor regardless of the position of the blank holder 14. For example, the light source may emit laser light in a direction parallel to the axis of movement of the blank holder. In the example where an optical sensor is provided on the blank holder 14, the optical sensor may detect the laser beam regardless of the position of the blank holder 14. In the example where a reflective surface is provided on the blank holder, the two reflective surfaces can reflect the laser beam so that it travels in a direction parallel to the axis of movement of the blank holder 14 toward the optical sensor (regardless of the position of the blank holder 14). For example, the displacement of the blank holder 14 can be estimated by using timing measurements (the timing of the time difference between pulses of laser light emitted by the light source and detected by the optical sensor). In the example including reflective surfaces, knowledge of the arrangement (e.g., the distance between the two reflective surfaces and / or the speed of light in the prism) may be required to estimate the displacement of the blank holder 14.

[0099] As also mentioned above, the blank holder displacement sensor may include an accelerometer. For example, the accelerometer can measure the acceleration of the blank holder 14, and the measured acceleration can be used to determine the displacement of the blank holder 14.

[0100] While several exemplary embodiments are provided above, it should be understood that the displacement of the blank holder 14 can be measured in any manner.

[0101] The rivet insertion tool 2 may be provided with a punch displacement sensor. The punch displacement sensor may also be called a means for measuring the displacement of the punch. The punch displacement sensor may be, for example, a position sensor, an accelerometer, and / or an encoder. For example, an encoder can enable measurement of the motor 8 and / or actuator 12 to determine the displacement of the punch. As an example, an encoder may enable measurement of the speed of the motor 8 and / or actuator 12 as a function of time to determine the displacement of the punch. As an alternative example, the torque supplied by the motor 8 and / or actuator 12 can be measured, and the measured torque can be used to determine the displacement of the punch. As a further example of a punch displacement sensor, part of the blank holder 14 may be a notch. In other words, a slit may extend axially along the blank holder 14. The punch may be provided with a projection extending from the notch of the blank holder 14. The projection may enable measurement of the displacement of the punch using a contact displacement sensor (and optionally, components, e.g., a rod) or a light source and an optical sensor, in similar manner to those described above. In other words, a contact displacement sensor (for measuring punch displacement) can contact a protrusion (or a component fixed to the protrusion) and enable measurement of the punch displacement relative to a fixed position (i.e., the position of the contact displacement sensor). Alternatively, a light source may be provided at a fixed position, and an optical sensor may be provided on the protrusion. The optical sensor can enable measurement of the punch displacement relative to a fixed position.

[0102] The rivet insertion tool 2 may be provided with a force sensor (referred to as the force sensor) for measuring the force exerted by the punch on the fastener. The force sensor may also be called a means for measuring the force exerted on the fastener by the punch. The force sensor may, for example, comprise the punch and may comprise, for example, a load cell and / or a calibrated strain gauge. Alternatively, the force sensor may comprise an encoder, which may enable position measurement of the motor 8 and / or actuator 12, which can be associated with time to determine the acceleration of the tool. Using the position measurements and mass of the rivet insertion tool 2, the force exerted by the punch on the fastener can be calculated. Alternatively, the values ​​may be calculated from a model of the rivet insertion tool 2. The model can measure the torque of the motor 8, the inertia of the actuator 12, and / or the current applied to the motor to determine its deceleration. The model can be calibrated to compensate for effects caused, for example, by temperature changes.

[0103] Although various components of rivet insertion tool 2 have been described above, it will be understood that rivet insertion tool 2 is merely an example, and any suitable rivet insertion tool can be used. In other words, the method disclosed herein may be carried out using other rivet insertion tools. For example, fasteners can be delivered to rivet insertion tools such as blow-feed systems using various delivery systems.

[0104] Figure 2 is a flowchart illustrating method 200 for determining the thickness of a workpiece. In step 201, the blank holder of the fastener set tool is advanced to the calibration position. In step 202, the position of the calibration position is measured. In step 203, the blank holder is advanced to contact the surface of the workpiece. In step 204, the position on the surface of the workpiece is measured. In step 205, the thickness of the workpiece is determined. In an optional step 206, the fastener is inserted into the workpiece. In an optional step 207, the blank holder 314 and / or punch 312 may be retracted.

[0105] Figures 3A–3F (i.e., Figures 3A, 3B, 3C, 3D, 3E, and 3F together) schematically illustrate a system 300 comprising a fastener set tool 310 during method 200 for determining the thickness of a workpiece. Figures 3A–3F are used to illustrate in more detail the actions caused by method 200 (and other methods described later, e.g., methods 400 and 500). Although different reference numerals are used in Figures 3A–3F than in Figure 1, it should be understood that method 200 can be performed using the fastener set tool 2 shown in Figure 2.

[0106] Figure 3A shows a system 300 comprising a fastener setting tool 310. The fastener setting tool 310 comprises a blank holder 314 and a punch 312 (the punch 312 is not shown in Figure 2). A fastener 320 is held within the blank holder 314 in a position below the punch 312. Although the fastener 320 is shown (in Figure 3A) in a position below the punch 312 inside the blank holder 314, this is not mandatory, and the fastener 320 can be moved to such a position later. The fastener 320 may be a rivet, for example, a self-piercing rivet. The system 300 further comprises a die 306. The initial position of the upper surface of the die 306 is indicated by a reference line 340. The blank holder 314 and punch 312 are in a retracted position. In other words, there is space between the end of the blank holder 314 configured to contact the workpiece and the die 306. The fastener setting tool 310 comprises a blank holder displacement sensor. The blank holder displacement sensor is not shown and may be, for example, any of the examples described above (i.e., the blank holder displacement sensor may comprise a contact displacement sensor, a light source and a light-gauge sensor, and / or an accelerometer). The fastener set tool 310 may further comprise a punch displacement sensor and / or force sensor (for measuring the force exerted on the fastener 320 by the punch 312).

[0107] Referring again to Figure 2, in step 201, the blank holder 314 is advanced to the calibration position. The calibration position may be the position of the blank holder 314 when it contacts the surface of the die 306. In other words, the blank holder 314 may contact the surface of the die 306 on which the workpiece may be placed. The blank holder 314 may reach the reference line 340. The blank holder 314 may advance with relatively slow and / or relatively low force (i.e., slower or less force than the typical operation of the blank holder 314 as described in step 203) so as not to deform the blank holder 314 or the die 306 (or any other component) by the force applied to or by the blank holder 314.

[0108] Alternatively, the calibration position may be the position of the blank holder 314 when it contacts the surface of the calibration member positioned on the die 306. For example, the calibration member may be a nominal workpiece (i.e., a workpiece determined to have nominal dimensions). In other words, the calibration member may have the same thickness as the expected thickness of the workpiece.

[0109] As a further alternative, the calibration position may be the position of the blank holder 314 (or a part of the blank holder 314) when it is aligned with an alignment marker provided on the fastener set tool 310, for example, the C-frame. For example, a first visible tab may be provided on the blank holder 314, and a second visible tab may be provided on a part of the C-frame, and the calibration position may be the position of the blank holder 314 when the first and second visible tabs are aligned.

[0110] Figure 3B shows the system 300 after the blank holder 314 has been advanced to the calibration position (as in step 201). In the example shown in Figure 3B, the calibration position is the position of the blank holder 314 when it contacts the surface of the die 306. The punch 312 and fastener 320 remain in the retracted position. The punch 312 and fastener 320 are shown moving in substantially the same manner as the blank holder 314 (i.e., the punch 312 and fastener 320 do not move relative to the blank holder 314), but this is not necessarily required. The punch 312 and fastener 320 can remain in the same position relative to the die 306 as shown in Figure 3A. In other words, because the force applied to the die 306 by the blank holder 314 is relatively low, the top surface of the die 306 remains in the initial position indicated by the reference line 340.

[0111] Referring again to Figure 2, in step 202, the position of the calibration position is measured. In an example where the calibration position is the position of the blank holder 314 when it is in contact with the die 306, the position on the surface of the die 306 is measured. In other words, the first position on the surface of the die 306 may be measured. The position of the calibration position can be measured using a blank holder displacement sensor as described above with reference to Figure 1. The calibration position may also be measured along the axis on which the blank holder 314 moves.

[0112] In an example where the contact displacement sensor 20 of the fastener set tool 310 is fixed to the blank holder 314, the displacement of the blank holder 314 can be measured by measuring the displacement of the contact displacement sensor 20. For example, as described above, the member 30 can be fixed to a fixed point, the contact displacement sensor 20 can be fixed to the blank holder 314, and the displacement of the blank holder 314 can be estimated by measuring the displacement of the contact displacement sensor 20 relative to the member 30. Measuring the position of the calibration position may include measuring the first position of the contact displacement sensor 20. In other words, the first position of the contact displacement sensor 20 (relative to the member 30) can be measured while the blank holder 314 is in the calibration position. The position of the calibration position can be expressed as the distance the blank holder 314 has moved to advance to the calibration position and / or to contact the surface of the die 306.

[0113] Although die 306 is shown to have a substantially flat upper surface, in some examples the die may be shaped to facilitate the spreading of the self-piercing rivet. Such a die may not make uniform contact with the workpiece. There may be areas on the die that are not expected to be in contact with the workpiece (when the workpiece is first placed on the die). The blank holder 314 does not have to make uniform contact with such a die (i.e., portions of the blank holder 314 that can be in contact with the workpiece do not have to be in contact with die 306). Using such a die, the first position on the surface of die 306 may be measured at a point on the surface of die 306 that is expected to be in contact with the workpiece and / or the blank holder 314.

[0114] The position of the calibration position can be measured while the fastener set tool is positioned as shown in Figure 3B (as described above). For example, a blank holder displacement sensor can be used to determine the position of the blank holder 314 while it is in the calibration position.

[0115] Method 200 may further include retracting the blank holder 314 so that a workpiece can be inserted between the blank holder 314 and the die 306. In other words, the blank holder 314 may be retracted by at least the thickness of the workpiece. In examples where the method includes the use of a calibration member, retracting the blank holder 314 can allow the calibration member to be removed. Retraction of the blank holder 314 is not always necessary. For example, in examples where the calibration position is indicated by first and second visible tabs, the workpiece may be placed on the die 396 while the blank holder 314 is in the calibration position.

[0116] Method 200 may further include positioning the workpiece 330 in a predetermined location on the die 306. In other words, the workpiece 330 into which the fastener 320 is inserted is positioned in a suitable location on the die 306 in a normal manner.

[0117] Figure 3C shows a system 300 comprising a fastener set tool with a blank holder 314 in the retracted position. The workpiece 330 is positioned in place on the die 306. The workpiece 330 is shown as comprising two panels (a first panel 331 and a second panel 332), but a workpiece comprising additional panels and other materials (e.g., interlayer material such as adhesive) may be used. The weight of the workpiece 330 imparts a relatively small force (compared to the force applied by the punch 312), so the top surface of the die 306 remains in substantially the same position as the initial position indicated by the reference line 340.

[0118] Referring again to Figure 2, in step 203, the blank holder 314 is advanced. The blank holder 314 can be advanced so that it contacts the surface of the workpiece 330. In other words, the blank holder contacts the upward surface of the uppermost panel 331 of the workpiece 330. Such operations of the fastener set tool 310 (e.g., retracting the blank holder 314, positioning the workpiece 330, and advancing the blank holder 314) are known in the art and can be performed in typical embodiments. The blank holder 314 can clamp the workpiece 330 in position relative to the die 306. Alternatively, the blank holder 314 may contact the workpiece 330 without providing little or no clamping force.

[0119] Figure 3D shows a system 300 comprising a fastening set tool in which a blank holder 314 is in contact with the surface of a workpiece 330. In the example in Figure 3D, the workpiece 330 is clamped against the die 306 by the force applied by the blank holder 314. As previously mentioned, because the force applied to the die 306 by the blank holder 314 is relatively low, the upper surface of the die 306 remains in the initial position indicated by the reference line 340.

[0120] In step 204, the position of the surface of the workpiece 330 is measured. The position of the surface of the workpiece 330 may be measured along the axis on which the blank holder 314 moves. The surface of the workpiece 330 (i.e., the workpiece measured in step 204) may be the surface of the workpiece 330 facing the blank holder 314 and / or the surface of the workpiece 330 that is in contact with the blank holder 314.

[0121] The position of the surface of the workpiece 330 can be measured in a manner similar to that used to measure the position of the calibration position (measured in step 202). That is, the position of the surface of the workpiece 330 may be measured using a blank holder displacement sensor. For example, measuring the position of the surface of the workpiece 330 may include measuring the second position of the contact displacement sensor 20 relative to the member 30. As described above, the measured position of the surface of the workpiece 330 can be expressed as the distance the blank holder 314 has moved from the calibration position to the position where the blank holder 314 contacts the surface of the workpiece 330.

[0122] The position of the surface of the workpiece 330 may be measured while the fastener setting tool 310 is positioned as shown in Figure 3D and described above. In other words, the position of the surface of the workpiece 330 can be measured while the blank holder 314 is in contact with the surface of the workpiece 330. Figure 3D shows the fastener setting tool 310 with a fastener 320 in a position ready to be inserted into the workpiece 330, although the fastener 320 is not required for the fastener setting tool 310 to perform method 200 for determining the thickness of the workpiece 330.

[0123] In step 205, the thickness of the workpiece 330 is determined. Determining the thickness of the workpiece 330 may involve using the measurement location of the calibration position (measured in step 202) and the measurement location on the surface of the workpiece 330 (measured in step 204). In other words, in an example where the calibration position is the position of the blank holder 314 when it contacts the surface of the die 306, the difference between the measurement location of the calibration position and the measurement location on the surface of the workpiece 330 may correspond to the thickness of the workpiece 330. Such a determined thickness is sometimes called an absolute thickness because the determined thickness is not determined by referring to the thickness of another object (i.e., the calibration member).

[0124] Alternatively, the determined thickness may be a relative thickness. For example, the calibration position (as described above) can be measured using a calibration member and / or alignment marker. In such an example, the determined thickness of the workpiece 330 (determined in step 205) may be relative to the thickness of the calibration member and / or the thickness corresponding to the alignment marker. For example, the workpiece 330 may be determined to be 1 mm thicker than the thickness of the calibration member.

[0125] Method 200 may further include obtaining the thickness of the calibration member and / or the thickness corresponding to the alignment marker (i.e., the thickness of the calibration member that will extend from the surface of the die 306 to the alignment marker). For example, the thickness of the calibration member may be measured separately, and the measured thickness may be given for use in Method 200. For example, the measured thickness may be stored in memory and retrieved from the storage device during Method 200. Method 200 may further include determining the absolute thickness from the relative thickness. For example, the calibration member may be 1 mm thick, and the workpiece 330 may be determined to have a relative thickness (relative to the calibration member) of 4.6 mm. The workpiece 330 may be determined to have an absolute thickness of 5.6 mm.

[0126] The dimensions of the workpiece 330 corresponding to the determined thickness may be dimensions parallel to the movement of the blank holder 14. The thickness of the workpiece 330 may be determined while the fastener setting tool 310 is in any position. For example, the thickness of the workpiece 330 may be determined immediately after the position of the surface of the workpiece 330 is measured (i.e., before the fasteners are inserted). Thus, the fastener setting tool 310 may be positioned as shown in Figure 3D when the thickness of the workpiece 330 is determined. Alternatively, the thickness of the workpiece 330 may be determined at a later point, for example, after the fasteners 320 have been inserted into the workpiece 330.

[0127] In an optional step 206, the fastener 320 can be inserted into the workpiece 330. The fastener 320 can be inserted using the punch 312 of the fastener setting tool 310. The fastener 320 may be a self-piercing rivet. In the example where the fastener 320 is a self-piercing rivet, the punch 312 can apply force to the self-piercing rivet 320 so that it is inserted into the workpiece 330 in an area near or directly above the die 306. Once the self-piercing rivet 320 is inserted into the workpiece 330, it may spread outwards. In other words, a portion of the self-piercing rivet 320 may be forced outwards radially from the axis extending through the self-piercing rivet 320.

[0128] Figure 3E shows a system 300 comprising a fastener set tool 310 in which a workpiece 306 is clamped in place relative to a die 306 by a blank holder 314. A punch 312 advances from its initial position, inserting a fastener 320 into the workpiece 330. Although Figure 3E shows the punch 312 not protruding from the opening of the blank holder 314, this is merely illustrative and may not be the case. For example, the punch 312 may protrude from the opening of the blank holder 314 (at a position corresponding to the maximum displacement of the punch 312), thereby allowing the fastener 320 to be inserted into the workpiece 330 in the correct manner regardless of any deformation of the panels 331, 332 of the workpiece 330. Due to the relatively high force applied by the punch 312, the system flexes. As a result, the die 306 moves away from its initial position indicated by the reference line 340. The example in Figure 3E shows a portion of the punch 312 aligned with the reference line 340, but the system can flex more or less than shown.

[0129] The fastener 320 may be inserted before and / or after the thickness of the workpiece 330 is determined. The thickness of the workpiece 330 may be determined multiple times (i.e., one or more of steps 201, 202, 203, 204, and 205 may be performed multiple times). For example, the position of the surface of the workpiece 330 may be measured first, the thickness of the workpiece 330 may be determined first, and the initially determined thickness may be used to determine whether the workpiece 330 is suitable for the fastener 320 into which it will be inserted. The fastener 320 may then be inserted. The position of the surface of the workpiece 330 may be measured a second time, the thickness of the workpiece 330 may be determined a second time, and the second thickness of the workpiece 330 may be used to determine the tool deflection (see Method 400, which will be described in more detail below). Alternatively, the thickness of the workpiece 330 may be determined at a single time and used to determine whether the workpiece 330 is suitable for the fastener 320 into which it will be inserted and to determine the tool deflection.

[0130] In the optional step 207, the blank holder 314 and / or punch 312 may be retracted. In other words, the blank holder 314 and punch 312 may be retracted to an initial position where method 200 is ready to start again on another workpiece. The position in which the blank holder 314 is retracted may be the calibration position.

[0131] Figure 3F shows the system 300 with the blank holder 314 and punch 312 retracted. As seen in Figure 3F, the fastener 320 remains inserted into the workpiece 330, and the workpiece 330 can be removed from the die 306. The blank holder 314 and / or punch 312 may be retracted at any appropriate point after the fastener 320 has been inserted into the workpiece 330. The die 306 can return to its initial position once the punch 312 has stopped applying force. Alternatively, method 200 may further include resetting the system 300, i.e., returning the die 306 to its initial position. In other words, the die 306 can be moved so that its upper surface is aligned with the reference line 340.

[0132] The determined thickness may be stored. For example, the determined thickness may be stored in computer-readable memory. The determined thickness may also be stored in a database containing other characteristics relating to the fastener 320, the joint, the workpiece 330, and / or the fastener insertion tool 310. For example, an identifier corresponding to the workpiece 330, the location of the joint within the workpiece 330, and the type of fastener 320 may also be stored in the database.

[0133] The determined thickness can be tested against predetermined values ​​in a threshold test. For example, a threshold test may test whether the determined thickness of the workpiece 330 is less than one or more predetermined values, greater than one or more predetermined values, less than or equal to one or more predetermined values, greater than or equal to one or more predetermined values, and / or equal to one or more predetermined values. A threshold test may be one of several threshold tests. In other words, multiple threshold tests can be applied to the determined thickness, and the results can be combined, for example, using Boolean logic. Each threshold test may provide a binary result (i.e., either a0 or a1). A result of 1 may indicate that the threshold test was passed (i.e., the conditions tested in the threshold test were met). The results of a threshold test may be expressed as a warning indicator and / or a failure indicator. The results of a threshold test can be used to indicate that a particular operation is recommended and / or required. The results of a threshold test can be used to cause a particular operation to be performed.

[0134] Based on the results of a threshold test applied to the determined thickness, it can be determined that the workpiece 330 should be replaced. For example, a threshold test can be used to test whether the determined thickness of the workpiece 330 is within a certain range of values. In other words, the nominal thickness may be 6 mm and the corresponding tolerance may be 10% (i.e., the determined thickness may need to have values ​​of at least 5.4 mm and less than 6.6 mm). A workpiece 330 with a determined thickness of 5.6 mm can pass such a threshold test, and the workpiece 330 can be used in the normal manner. A workpiece 330 with a determined thickness of 7 mm may fail such a threshold test (i.e., ). If such a threshold test fails, the workpiece 330 can be identified as unsuitable for use in the process and / or product. An indication may be provided to show that the workpiece 330 should be replaced. Additionally or alternatively, the workpiece 330 may be replaced. In other words, workpiece 330 may be removed from the process (it may not be used to construct the product to be manufactured), and a different workpiece 330 may be used.

[0135] Based on the results of a threshold test applied to the determined thickness, it can be determined that the fastener set tool 310 requires maintenance. If such a threshold test is met, it can be determined that the fastener set tool 310 is within normal operating conditions. Alternatively, if such a threshold test fails, it can be determined that the fastener set tool 310 requires maintenance. An indicator can be provided to show that the fastener set tool 310 requires maintenance and / or specifically what kind of maintenance is required. Additional or alternative maintenance can be performed. In other words, the fastener set tool 310 can perform the necessary maintenance itself or can have the necessary maintenance performed.

[0136] Based on the results of threshold tests applied to the determined thickness, it can be determined that parameters related to the fastener set tool 310 should be adjusted. For example, a threshold test can be used to test whether the determined thickness of the workpiece 330 is less than a value, e.g., 5.4 mm. If such a threshold test is met, the fastener set tool 310 can, for example, reduce the force used to insert the fasteners 320 into the workpiece 330. As another example, a threshold test can be used to test whether the determined thickness of the workpiece 330 is greater than a value, e.g., 6.6 mm. If such a threshold test is met, the fastener set tool 310 can, for example, increase the force used to insert the fasteners 320 into the workpiece 330. If any of the exemplary threshold tests described herein fail (i.e., the determined thickness of the workpiece 330 is between 4 mm and 5 mm), the determined thickness of the workpiece 330 is determined to be acceptable, and the parameters related to the fastener set tool 310 cannot be adjusted. Other exemplary parameters that can be adjusted include, for example, the type of fastener to be inserted (i.e., a first type of rivet may be changed for a second type of rivet), the type of die on the fastener setting tool 310, the amount of adhesive provided between the panels 331 and 332 of the workpiece 330, the end position of the punch 312, and / or the clamping force applied by the blank holder 314. The parameters can be changed for or in relation to the workpiece 330 whose thickness has been determined. In other words, an increased force can be used to insert the fastener 310 into the measured workpiece 330. Additionally or alternatively, the parameters may be changed for subsequent workpieces. In other words, an increased force can be used to insert the fastener into the workpiece following the measured workpiece 330.

[0137] Figure 4 shows a flowchart of method 400 for determining tool deflection. In step 401, the fastener 320 is inserted into the workpiece 330. In step 402, the thickness of the workpiece 330 is determined. In step 403, the position of the upper end face of the fastener 320 is measured. In step 404, the head height of the fastener 320 is obtained. In step 405, the tool deflection is determined. In an optional step 406, the deflection coefficient can be determined.

[0138] In step 401, the fastener 320 is inserted into the workpiece 330. The fastener 320 can be inserted into the workpiece 330 as described above in relation to method 200. In the example of method 400 in which the deflection coefficient is determined, inserting the fastener into the workpiece 330 may further include determining the peak force exerted on the fastener 320 by the punch 312.

[0139] The peak force exerted on the fastener 320 by the punch 312 can be measured using a force sensor. The force can be measured continuously (or discretely at a high sampling rate) as a function of time, and the recorded maximum force can be determined. Alternatively, the force may be measured at one or more points in time. One or more points in time may be determined (i.e., triggered) by other measurements. For example, the displacement of the punch 312 can be measured by measuring the position of the motor 8 (as described above in relation to the force sensor). The measured displacement of the punch 312 may be used to determine the speed at which the punch 312 moves, and the determined speed may be used to determine the point in time at which the force should be measured (by the force sensor) or calculated (from the model of the rivet insertion tool 2). For example, the speed of the punch 312 can be determined, and when the speed of the punch 312 falls below a value, e.g., 4 mm / s, the calculation of the force exerted on the fastener 320 by the punch 312 can be triggered.

[0140] In step 402, the thickness of the workpiece 330 is determined. The thickness of the workpiece 330 can be determined as described above in relation to method 200, particularly in relation to step 205.

[0141] In step 403, the position of the upper end face of the fastener 320 is measured. The upper end face of the fastener 320 may be the surface of the fastener 320 that faces and / or contacts the punch 312. In other words, the position of the surface of the fastener 320 that faces the punch 312 can be measured. The upper end face of the fastener 320 may be the surface of the fastener 320 that is closest to the blank holder 314 when the blank holder 314 is in the retracted position (i.e., as shown in Figure 3A).

[0142] The position of the upper end face of fastener 320 can be measured relative to a measured position on the surface of die 306 (as measured in step 202). The position of the upper end face of fastener 320 may also be measured relative to a calibration position. The position of the upper end face of fastener 320 can be measured using a punch displacement sensor. As the displacement of punch 312 positions fastener 320, the maximum displacement of punch 312 can correspond to the position of the upper end face of fastener 320. Thus, it can be assumed that the maximum displacement of punch 312 corresponds to the position of the upper end face of fastener 329.

[0143] Alternatively, the position of the upper end surface of the fastener 320 may be measured using a blank holder displacement sensor. For example, as the blank holder 314 moves forward, the blank holder 314 may be retracted so that it contacts the upper end surface of the fastener 320, thereby moving the position of the workpiece 330 (and the fastener 320).

[0144] In step 404, the head height of the fastener 320 may be received and / or measured. The measured head height of the fastener 320 may be measured manually by an operator having, for example, a DTI gauge (dial test indicator), and the measured head height may be provided as input to the fastener setting tool 310, for example, via a human-machine interface. Alternatively, other measuring devices may be used, for example, a measuring device that uses optical effects to measure the head height of the fastener 320.

[0145] In step 405, the tool deflection can be determined. The tool deflection can correspond to the change in the end position relative to the starting position of the components of the fastener set tool 310 due to the insertion of the fasteners. In other words, the components of the fastener set tool 310 can be moved by the force applied to the fasteners 320 during the insertion of the fasteners 320. The end position may also be the position of the components before the punch 312 and blank holder 314 are retracted. In other words, the end position can correspond to the position of the components as shown in Figure 3E (for simplicity, the movement due to tool deflection is not shown in any of Figures 3A to 3F). Examples of components that can be moved by deflection include the C-frame, die 306, and / or one or more linkages within the fastener set tool 310. Since the distance between the end position of the punch 320 and the end position of the die 306 is generally equal to the sum of the thickness of the workpiece 330 and the head height of the fastener 320, each measured (or determined) value of the end position of the punch 320, i.e., the thickness of the workpiece 330 and the head height of the fastener 320, may be used to determine the tool deflection.

[0146] The tool deflection can be determined by using the measured head height of the fastener 320, the measured thickness of the workpiece 330, and the measured position of the upper end face of the fastener 320. In other words, the tool deflection TD can be determined as follows:

number

[0147] As mentioned above, the thickness of the workpiece 330 may be determined after the fastener 320 has been inserted into the workpiece 330. Beneficially, by performing the steps of method 400 in this order, the effect of the change in the thickness of the workpiece 330 due to the insertion of the fastener 320 on the determined tool deflection is minimized. Minimization may include completely eliminating the effect of the change in the thickness of the workpiece 330 due to the insertion of the fastener 320 into the tool deflection. Alternatively, the thickness of the workpiece 330 may be determined before the fastener 320 is inserted into the workpiece 330. Beneficially, by performing the method steps in this order, the overlap of measurements can be reduced and method 400 can be performed more quickly than other methods.

[0148] Tool deflection can be used to compare the deflection of the fastener set tool 310 when inserting different fasteners, and / or to determine the properties of the fasteners 320, joints, workpieces 330, and / or the fastener set tool 310. For example, tool deflection can be used to determine the deflection coefficient, and the deflection coefficient can be used to determine the head height of the fastener 320 (described below). As a further example, tool deflection can indicate wear of components of the fastener set tool 310, and changes in tool deflection over a period of time (of similar fasteners and workpieces) can indicate that one or more components of the fastener set tool 310 require maintenance and / or replacement.

[0149] Method 400 may further include determining a deflection coefficient of the fastener setting tool 310 that corresponds to the deflection with respect to the peak force exerted on the fastener 320 by the punch 312. The deflection coefficient DF can be determined as follows:

number

number

[0150] For example, if the measured head height is 0.02 mm, the measured thickness is 5.63 mm, the measured punch position is 3.25 mm, and the measured peak force is 57.40 kN, the tool deflection can be determined to be 2.40 mm, and the deflection coefficient can be determined to be 0.042 mm / kN.

[0151] The tool deflection and / or deflection coefficient may be determined at regular intervals or in response to specific events. For example, the tool deflection and / or deflection coefficient may be determined after a set number of fasteners have been inserted, for example, after 250,000 or 500,000 fasteners have been inserted. The tool deflection and / or deflection coefficient can be determined after maintenance work has been performed on the fastener set tool 310 and / or die 306. The tool deflection and / or deflection coefficient may be determined when components from different batches are used, for example, when fasteners 320 from different batches are used, and / or when the workpiece 330 includes panels 331, 332 from different batches.

[0152] The deflection and / or deflection coefficient of the tool can be stored. For example, the deflection and / or deflection coefficient of the tool may be stored in computer-readable memory. The deflection and / or deflection coefficient of the tool may also be stored in a database that has other characteristics relating to the fastener 320, the joint, the workpiece 330, and / or the fastener insertion tool 310. For example, an identifier corresponding to the workpiece 330, the location of the joint within the workpiece 330, and the type of fastener 320 may also be stored in the database. Other characteristics may include, for example, the type of die 306 and / or the type of adhesive.

[0153] The tool deflection and / or deflection coefficient can be tested against predetermined values ​​in a threshold test, in a manner similar to that described above with respect to the determined thickness of the workpiece 330. The results of the threshold test may be expressed as warning indicators and / or failure indicators. The results of the threshold test can be used to indicate that a particular operation is recommended and / or required. The results of the threshold test can be used to cause a particular operation to be performed.

[0154] Based on the results of a threshold test applied to the deflection and / or deflection coefficient of the tool, it may be determined that the workpiece 330 should be replaced. For example, a threshold test can be used to test whether the deflection and / or deflection coefficient of the tool are within a certain range of values. If such a threshold test fails, the component (e.g., the workpiece 330, the fastener set tool 310, or a part of either the workpiece 330 or the fastener set tool 310) may be identified as unsuitable for use in the process and / or product. An indication may be provided to show that the component should be replaced. Additionally or alternatively, the component may be replaced. In other words, the component may be removed from the process (it may not be used to construct the product to be manufactured), or a different component may be used. As an example, the C-frame 4 may be a component that can be identified as unsuitable for use in the process.

[0155] Based on the results of threshold tests applied to the tool deflection and / or deflection coefficient, it can be determined that the fastener set tool 310 requires maintenance. For example, a threshold test can be used to test whether the determined tool deflection is lower than a threshold tool deflection value, e.g., 2 mm. If such a threshold test is met, it can be determined that the fastener set tool 310 is within normal operating conditions. Alternatively, if such a threshold test fails, it can be determined that the fastener set tool 310 requires maintenance. An indicator can be provided to show that the fastener set tool 310 requires maintenance and / or specifically what kind of maintenance is required. Additional or alternative maintenance can be performed. In other words, the fastener set tool 310 can perform the necessary maintenance itself or can have the necessary maintenance performed on it.

[0156] Based on the results of threshold tests applied to the tool deflection and / or deflection coefficient, it may be determined that parameters related to the fastener set tool 310 should be adjusted. For example, a threshold test can be used to test whether the tool deflection is greater than a value, e.g., 3 mm. If such a threshold test is met, the fastener set tool 310 may, for example, increase the force used to insert the fastener 320 into the workpiece 330. As another example, a threshold test can be used to test whether the tool deflection is less than a value, e.g., 2 mm. If such a threshold test is met, the fastener set tool 310 may, for example, decrease the force used to insert the fastener 320 into the workpiece 330. If any of the exemplary threshold tests described herein fail, the tool deflection and / or deflection coefficient may be determined to be acceptable, and no adjustments may be made to the parameters related to the fastener set tool 310. Other exemplary parameters that can be adjusted include, for example, the type of fastener to be inserted (i.e., a first type of rivet may be changed for a second type of rivet), the amount of adhesive provided between panels 331 and 332 of the workpiece 330, the end position of the punch 312, and / or the clamping force applied by the blank holder 314.

[0157] Figure 5 shows a method 500 for determining the characteristics of the fastener 320. In step 501, the stored deflection coefficient is received. In step 502, the determined peak force is received. In step 503, the determined thickness of the workpiece is received. In step 504, the determined position of the upper end face of the fastener is received (504). In step 505, the head height is determined.

[0158] Refer again to Figures 3A to 3F to explain Method 500.

[0159] Method 500 can be used to determine the characteristics of a fastener 320 that has already been inserted into the workpiece 330. For example, the peak force (used to insert the fastener 320 into the workpiece 330) may be determined during the insertion of the fastener 320, and the determined peak force may be used in Method 500 (step 505). Alternatively, Method 500 may include inserting the fastener 320 and measuring the peak force during the insertion of the fastener 320. As a further alternative, the fastener 320 may be inserted with a predetermined peak force, and this predetermined peak force may be used in Method 500. The fastener 320 may be inserted with a predetermined torque applied, which is used by the fastener setting tool 310.

[0160] In step 501, a stored deflection coefficient is obtained. The stored deflection coefficient may have been determined previously, as in method 400 (and described above). The stored deflection coefficient may be related to / associated with the position (or planned position) of the fastener 320 in workpiece 330 and / or similar workpieces. In other words, different deflection coefficients may be obtained if the fastener 320 was inserted (or planned to be inserted) in different positions in workpiece 330. The same deflection coefficient may be obtained if the fastener 320 was inserted (or planned to be inserted) in similar positions in similar workpieces 330. Alternatively, the deflection coefficient may be consistent across workpiece 330 and / or similar workpieces.

[0161] Method 500 may further include receiving and / or determining one or more characteristics of the fastener 320, the joint (i.e., the joint formed by the fastener 320) and / or the workpiece 330 (i.e., the workpiece 330 into which the fastener 320 is inserted or to which it will be inserted). For example, the location of the joint within the workpiece 330 can be determined and used to determine which stored deflection coefficient is to be received from a database (the database stores multiple deflection coefficients, each deflection coefficient having a corresponding location).

[0162] The deflection coefficient of system 300 (comprising a fastener set tool 310, a workpiece 330, and a fastener 320) may be constant (or nearly constant) for all systems including the same and / or similar types of fastener set tool 310, workpiece 330, and fastener 320. In other words, the deflection coefficient can make it possible to estimate the head height of the fastener 320 without directly measuring the head height of the fastener 320.

[0163] In step 502, the determined peak force is applied. The determined peak force can correspond to the peak force applied to the fastener 320 by the punch 312 of the fastener set tool 310. The determined peak force can be determined in the same manner as described above.

[0164] In step 503, the determined thickness of the workpiece 330 is obtained. The thickness of the workpiece 330 can be determined in the same manner as described above in method 200 and / or step 402.

[0165] In step 504, the determined position of the upper end face of the fastener 320 is obtained. The position of the upper end face of the fastener 320 can be determined in the same manner as described above in step 403.

[0166] In step 505, the head height of the fastener 320 is determined. The head height HH of the fastener 320 can be determined as follows.

number

[0167] The head height of the fastener 320 can indicate the characteristics of the workpiece 330 and / or the joint formed in the workpiece 330. For example, the head height can indicate the strength of the joint. The head height may also be called the position of the upper end face of the fastener 320 relative to the upper end face of the workpiece 330 in the region close to the fastener 320. The region close to the fastener 320 may directly surround the fastener 320 or may extend beyond the region deformed by the insertion of the fastener 320. The determined head height of the fastener 320 can provide an indication of the strength (or another characteristic) of the joint as an alternative to (or in addition to) destructive testing. For example, the head height of the first fastener 320 of the first workpiece 330 may be determined, and the strength of the corresponding first joint may be determined using destructive testing. The head height of the second fastener 320 of the second workpiece 330 may be determined and used to estimate the strength of the corresponding second joint based on the head height and strength of the first joint.

[0168] The determined head height may be stored. For example, the determined head height may be stored in computer-readable memory. The determined head height may also be stored in a database containing other characteristics relating to the fastener 320, the joint, the workpiece 330, and / or the fastener insertion tool 310. For example, an identifier corresponding to the workpiece 330, the location of the joint within the workpiece 330, and the type of fastener 320 may also be stored in the database.

[0169] The determined head height can be tested against a predetermined value in a threshold test, in the same manner as described above with respect to the determined thickness of the workpiece 330. The results of the threshold test may be expressed as a warning indicator and / or a failure indicator. The results of the threshold test can be used to indicate that a particular operation is recommended and / or required. The results of the threshold test can be used to cause a particular operation to be performed.

[0170] Based on the results of a threshold test applied to the determined head height, it can be determined that the workpiece 330 should be replaced. For example, a threshold test can be used to test whether the determined head height is within a certain range of values. In other words, the nominal head height may be 0.02 mm and the corresponding tolerance may be 10%. The determined head height may need to be at least 0.018 mm and less than 0.022 mm. A workpiece 330 with a determined head height of 0.019 mm will pass such a threshold test and can be used in normal manner. A fastener 320 with a determined head height of 0.023 mm may fail such a threshold test (i.e., pass the threshold test). If such a threshold test fails, the workpiece 330 and / or fastener 320 may be identified as unsuitable for use in the process and / or product. An indication may be provided to show that the workpiece 330 and / or fastener 320 should be replaced. Additionally or alternatively, the workpiece 330 and / or fastener 320 can be replaced. In other words, the workpiece 330 and / or fastener 320 may be removed from the process (and may not be used to construct the manufactured product), and different workpieces 330 and / or fasteners 320 may be used.

[0171] Based on the results of a threshold test applied to the determined head height, it can be determined that the fastener set tool 310 requires maintenance. For example, a threshold test can be used to test whether the determined head height is higher and / or lower than a threshold head height value, e.g., 0.025 mm. If such a threshold test is met, it can be determined that the fastener set tool 310 is within normal operating conditions. Alternatively, if such a threshold test fails, it can be determined that the fastener set tool 310 requires maintenance. An indicator can be provided to show that the fastener set tool 310 requires maintenance and / or specifically what kind of maintenance is required. Additional or alternative maintenance can be performed. In other words, the fastener set tool 310 can perform the necessary maintenance itself or have the necessary maintenance performed by it.

[0172] Based on the results of threshold tests applied to the determined head height, it may be determined that parameters related to the fastener setting tool 310 should be adjusted. For example, a threshold test can be used to test whether the determined head height of the fastener 320 is less than a value, e.g., 0.025 mm. If such a threshold test is met, the fastener setting tool 310 can, for example, reduce the force used to insert the fastener 320 into the workpiece 330. As another example, a threshold test can be used to test whether the determined head height of the fastener 320 is greater than a value, e.g., 0.03 mm. If such a threshold test is met, the fastener setting tool 310 can, for example, increase the force used to insert the fastener 320 into the workpiece 330. If any of the exemplary threshold tests described herein fail, the determined head height of the fastener 320 may be determined to be acceptable, and no adjustments to the parameters related to the fastener setting tool 310 may be necessary. Other exemplary parameters that can be adjusted include, for example, the type of fastener 320 to be inserted (i.e., a first type of rivet may be changed for a second type of rivet), the type of die 306, the amount of adhesive provided between the panels 331 and 332 of the workpiece 330, the end position of the punch 312, and / or the clamping force applied by the blank holder 314.

[0173] Figure 6 is a flowchart showing a method 600 for determining the force to insert the fastener 320. In step 601, the required head height of the fastener 320 is received. In step 602, the thickness of the workpiece 330 is received. In step 603, the deflection coefficient is received. In step 604, the desired position of the upper end face of the fastener 320 is received. In step 605, the force to be applied to the fastener 320 is determined.

[0174] In step 601, the required head height of the fastener 320 is determined. The required head height can be determined based on one or more characteristics of the workpiece 330 and / or the joint of the workpiece 330. For example, the head height of the fastener 320 is known to correspond to the strength of the joint made by the fastener 320 in the workpiece 330. The joint may need to have a minimum strength, which can be used to determine the required head height of the fastener 320. Additionally or alternatively, the workpiece 330 (at the time assembled into the product) may be expected to move relative to another part of the product, and the expected movement can be used to determine the required head height of the fastener 320. For example, the workpiece 330 may be a car door frame, and the corresponding door may be expected to move relative to the door frame. Such movement can provide the maximum head height of the fastener 320 inserted into the workpiece 330. In other words, if the fastener 320 has a head height exceeding the maximum value, the door 320 may contaminate the door frame and obstruct the necessary movement of the door (for example, the door may not be able to open and / or close).

[0175] In step 602, the thickness of the workpiece 330 is received. The received thickness of the workpiece 330 may be determined as in method 200 described above. Additionally or alternatively, the thickness of the workpiece 330 may be determined using any method or apparatus known in the art. For example, a set of calipers may be used. Additionally or alternatively, the thickness of the workpiece 330 may be the nominal thickness of the workpiece.

[0176] In step 603, a deflection coefficient is received. The received deflection coefficient can be determined as in method 200 described above. The deflection coefficient can be received in a similar manner to receiving the stored deflection coefficient (in step 501). The deflection coefficient can correspond to the position of the joint in the workpiece 330, one or more properties of the workpiece 330 (e.g., the hardness of panels 331 and 332 in the workpiece 330), one or more properties of the fastener set tool 310 (e.g., the stiffness of the C-frame 4), and / or one or more properties of the fastener 320 (e.g., the hardness or spread of the fastener 320).

[0177] In step 604, a desired position of the upper end face of the fastener 320 is obtained. The desired position of the upper end face of the fastener 320 may be determined based on one or more characteristics of the workpiece 330 and / or the fastener 320. Additionally or alternatively, a fastener previously inserted into the workpiece can be used to determine the desired position of the upper end face of the fastener 320.

[0178] In step 605, the force to be applied to the fastener 320 is determined. In other words, after using the determined force to insert the fastener 320 into the workpiece 330, the head height of the fastener 320 may be equal to (or approximately equal to) the required head height. The force PF can be determined as follows:

number

[0179] Method 600 may further include inserting the fastener 320 into the workpiece 330 using the punch 312 of the fastener set tool 310. The determined force (i.e., the force determined in step 605) can be applied to the fastener 320 using the punch 312.

[0180] Figure 7 is a flowchart showing a method 700 for determining the characteristics of a workpiece 330 or a joint formed on the workpiece 330 (i.e., a joint formed by the fastener 320). In step 701, the blank holder of the fastener set tool 310 contacts the surface of the workpiece 330. In step 702, a force is applied to the blank holder 314. In step 703, movement of the workpiece 330 is detected. In an optional step 704, predetermined characteristics may be determined to be present in the detected movement. In step 705, the characteristics of the workpiece 330 or the joint formed on the workpiece 330 are determined. In an optional step 706, the fastener 320 can be inserted into the workpiece 330.

[0181] In step 701, the blank holder 314 of the fastener set tool 310 comes into contact with the surface of the workpiece 330. In other words, the blank holder 314 can come into contact with the surface of the workpiece 330 as shown in Figure 3D. The blank holder 314 can be moved to come into contact with the surface of the workpiece 330 at a slow speed and / or with a low force so that the moment when the blank holder 314 comes into contact with the surface of the workpiece 330 can be identified and / or measured. For example, after coming into contact with the surface of the workpiece 330, the speed of the blank holder 314 or the force acting on it can be changed.

[0182] In step 702, a force is applied to the blank holder 314. The force may be applied axially toward the workpiece 330 (314). In other words, the blank holder 314 may have an axis that allows (or is parallel to) the blank holder 314 to move. The force may be applied along the axis toward the workpiece 330 (314). The force may be a consistent force, i.e., the force may have a constant magnitude and / or direction during the time the force is applied. The force may be applied continuously while detecting the movement of the workpiece 330. In other words, steps 702 and 703 may be performed simultaneously. Alternatively, the movement of the workpiece 330 may be detected after the application of force has stopped.

[0183] The magnitude of the applied force can be selected such that the applied force causes some movement, and that movement can be detected. For example, the applied force may be sufficient to close the panel gap (i.e., the area of ​​air space between adjacent panels 331 and 332 of the workpiece 330) for a measurable period of time. As another example, the applied force may be large enough to cause measurable vibration in the workpiece 330, but small enough not to significantly dampen or over-dampe the vibration. In other words, if the applied force is too large, it will prevent panels 331 and 332 from vibrating.

[0184] In step 703, movement of the workpiece 330 is detected. This movement may be caused by a force applied to the blank holder 314. This movement can be detected by measuring the displacement of the blank holder 314. In other words, while the blank holder 314 is in contact with the workpiece 330 and a force is applied to the blank holder 314 in the direction of the workpiece 330, the movement of the workpiece 330 causes movement of the blank holder 314. This movement may coincide with the axis of the blank holder 314. The movement of the blank holder 314 can change the displacement of the blank holder 314. The change in the displacement of the blank holder 314 can be measured by a blank holder displacement sensor. For example, in an example where the workpiece 330 vibrates, the blank holder 314 may also vibrate, and the movement of the blank holder 314 may be detected by a blank holder displacement sensor.

[0185] In the optional step 704, a predetermined feature may be determined to be present in the detected motion. In other words, a predetermined feature may be identified in the detected motion. For example, a predetermined feature may include a consistent motion in a single direction. Alternatively, a predetermined feature may include oscillation.

[0186] In step 705, the properties of the workpiece 330 or the joint formed on the workpiece 330 are determined. The properties may be determined based on the determination that there are predetermined characteristics in the detected movement (i.e., the movement detected in step 703) and / or the detected movement. The properties may be, for example, the presence of a gap between panels, the size of the gap between panels, the presence of adhesive and / or the amount of adhesive present. Additionally or alternatively, the properties may be the stiffness, ductility, and / or strength (e.g., ultimate tensile strength) of one or more panels 331, 332 within the workpiece 330.

[0187] In an optional step 706, the fastener 320 can be inserted into the workpiece 330. For example, the fastener 320 can be inserted using the punch 312 of the fastener setting tool 310. Force may be applied to the blank holder 314 before, during, and / or after insertion of the fastener 320. In an example in which method 700 includes inserting the fastener 320 into the workpiece 330, the movement of the workpiece 330 may include movement corresponding to the insertion of the fastener 320 into the workpiece 330 (by the punch 312 of the fastener setting tool 310). In an example in which method 700 includes inserting the fastener 320 into the workpiece 330, the characteristics may be distortion and / or deflection of the workpiece 330 (or panels 331, 332 of the workpiece 330). The distortion may correspond to a head-down gap, underfill and / or overfill in the area close to the fastener 320.

[0188] As a first example of Method 700, the workpiece 330 may comprise two panels 331, 332 with a panel gap between them. A blank holder 314 can contact the surface of the workpiece 330, and the blank holder 314 can apply force toward the workpiece 330. Under the applied force, the panels 331, 332 of the workpiece 330 can be compressed together, reducing or closing the panel gap. In other words, the panels 331, 332 can move gradually together, causing a similar gradual movement of the blank holder 314. The gradual movement of the blank holder 314 may be detected by a blank holder displacement sensor, and the detected movement may be used to identify the presence of a panel gap. The force may be applied until the panels 331, 332 stop moving, for example, because the panel gap is closed. The detected movement can also be used to determine the size of the panel gap that existed before the force was applied.

[0189] As a second example of Method 700, the workpiece 330 may comprise two panels 331, 332 with adhesive between them. A blank holder 314 can contact the surface of the workpiece 330, and the blank holder 314 can apply force toward the workpiece 330. Under the applied force, the panels 331, 332 of the workpiece 330 are compressed together, reducing the amount of adhesive between opposing points on the two panels 331, 332. In other words, the panels 331, 332 move gradually together, causing a similar gradual movement of the blank holder 314. The adhesive may also be pushed into the space between the two panels 331, 332, i.e., to spread the adhesive more evenly. Additionally or alternatively, the adhesive may be pushed out from the space between the two panels 331, 332. The gradual movement of the blank holder 314 may be detected by a blank holder displacement sensor, and the detected movement may be used to determine the presence of adhesive.

[0190] As a third example of method 700, the panels 331 and 332 of the workpiece 330 may be in a first position. After inserting the fastener 320 into the workpiece 330, the panels 331 and 332 of the workpiece 330 may move to a second position. In other words, a portion of the uppermost panel 331 may move downward, causing the blank holder 314 to move downward by a corresponding amount. The downward movement of the blank holder 314 can be detected by a blank holder displacement sensor. The detected movement can be used to determine that the material in the workpiece 330 has deformed during the insertion of the fastener 320.

[0191] As a fourth example of method 700, the fastener 320 can be inserted into the workpiece 330. While the fastener 320 is inserted, a portion of the workpiece 330 can bend upward. For example, a first portion of the workpiece 330 (i.e., near where the fastener 320 is inserted) may be pushed down from a first position into a die 306 having a recess. The shape of the die 306 (in particular, the recess) can cause a second portion of the workpiece 330 (i.e., further away from where the fastener 320 is inserted) to bend upward from the corresponding first position. Once the fastener 320 is inserted into the workpiece 330 (and the punch 312 is retracted), the first portion of the workpiece 330 may no longer be pushed down into the die 306. The first portion of the workpiece 330 may return to its first position, and the second portion of the workpiece 330 may return to its corresponding first position. Such movement of the first or second portion of the workpiece 330 can cause movement of the corresponding blank holder 314, which can be detected by a blank holder displacement sensor. The detected movement can be used to determine the brittleness and / or hardness of the panels 331, 332 of the workpiece 330.

[0192] Figure 8 is a flowchart illustrating method 800 for calculating and applying adjustments to a fastener set tool and / or workpiece. In step 801, the determined characteristics are compared with predetermined characteristics. In step 802, the adjustments are calculated. In step 803, the adjustments are applied.

[0193] As mentioned above, the performance of a fastener set tool can vary depending on the condition of the tool, for example, when the tool is cold, warm, or hot. By using Method 800, various performance characteristics of the tool can be compensated for. In particular, the effect of friction loss can be indirectly determined by measuring a first parameter and comparing it with a predetermined parameter. Thus, a compensation method is provided by calculating and applying adjustments. Such a compensation method can beneficially improve the performance of the tool.

[0194] As shown by the dashed line, Method 800 can be performed iteratively to form a feedback loop. That is, the steps of comparing, calculating, and applying adjustments may be repeated any number of times for the same or consecutive fasteners. In this way, the method can converge on parameters for inserting fasteners in such a way that it helps minimize tool wear while ensuring that the fasteners are inserted according to predetermined characteristics. For example, the tool can insert the fastener to the optimal head height with the minimum force required.

[0195] In step 801, the determined characteristic is compared with a predetermined characteristic. Generally, both the determined characteristic and the predetermined characteristic may relate to the same or similar characteristics. For example, the determined characteristic may be the determined head height of the first fastener, which may be determined using Method 500. The predetermined characteristic may be the predetermined head height. Alternatively, the determined characteristic may be the determined thickness of the workpiece, which may be determined using Method 200. The predetermined characteristic may be the predetermined thickness. As a further example, the determined characteristic may be the determined tool deflection, which may be determined using Method 400. The predetermined characteristic may be the predetermined tool deflection. As a further example, the determined characteristic may be the determined deflection coefficient, which may be determined using Method 400. The predetermined characteristic may be the predetermined deflection coefficient. The determined characteristic may be the presence or size of a panel gap. The predetermined characteristic may be the predetermined presence or size of a panel gap. It will be understood that other determined characteristics may be compared with other predetermined characteristics.

[0196] The predetermined characteristics may also be target values ​​for those characteristics. For example, the predetermined head height may be the target head height (i.e., nominal value) of the fastener.

[0197] The predetermined characteristics may be determined at an earlier stage. For example, the predetermined characteristics may be loaded from a database. Alternatively, the predetermined characteristics may be determined based on the previous insertion of one or more fasteners.

[0198] The determined characteristics may be based on multiple measurements. For example, the determined characteristics may be the average of determined head heights, where each determined head height corresponds to a different fastener. Each of the different fasteners may be at the same point on the corresponding workpiece. In other words, the characteristics of the joints on each workpiece can be determined and their average can be calculated. In another example, different fasteners may be on the same workpiece.

[0199] Comparing a determined characteristic with a predetermined characteristic may include calculating the difference between the determined characteristic and the predetermined characteristic. The comparison may further include applying a threshold and / or dividing the difference by a coefficient. For example, by applying a threshold, it may be determined that the tool requires adjustment. The threshold may correspond to a tolerance. For example, if the head height of the fastener is expected to be 0.2 mm with a tolerance of 0.02 mm, the predetermined characteristic may be 0.2 mm and the threshold may be 0.02 mm. Thus, if the fastener is inserted with a head height greater than 0.22 mm or 0.18 mm, adjustments may be determined and applied in steps 802 and 803, respectively.

[0200] The difference between the determined characteristics and the predetermined characteristics may represent the condition of the fastener set tool or the workpiece. The condition of the fastener set tool may include, or may include, temperature, age, previous use of the tool, and lubrication characteristics (e.g., lubrication amount, lubrication temperature). The condition of the workpiece may include, or may include, the strength, ductility, or properties of the fastener.

[0201] In step 802, the adjustment is calculated. Generally, the adjustment may be for any property on which the determined property depends. For example, if the determined property is the determined head height of the fastener, the adjustment may be for the torque or force applied by the fastener setting tool. Alternatively, the adjustment may be for the punch speed of the fastener setting tool.

[0202] The adjustment may be calculated to minimize the difference between the determined characteristic and the predetermined characteristic.

[0203] In some cases, the size of the adjustment may be calculated independently of the difference between the determined and predetermined characteristics. In other words, the adjustment may be an increment (or decrement) of a specific value, regardless of how much the determined and predetermined characteristics differ. For example, if the fastener has a determined head height of 0.3 mm (and a predetermined head height of 0.2 mm with a tolerance of 0.02 mm), the tool can be calculated to have a 5 kN increase in the torque applied by the fastener set tool. For any determined head height greater than 0.22 mm, the same 5 kN increase can be calculated.

[0204] In other examples, the size of the adjustment may be calculated based on the difference between a determined characteristic and a predetermined characteristic. In other words, the difference can be used to determine the adjustment. For example, if the determined head height is 0.5 mm, a larger adjustment may be applied when the predetermined head height is 0.2 mm than when the determined head height is 0.3 mm.

[0205] In step 803, the adjustment is applied. In some examples, the adjustment may be applied automatically; that is, the fastener set tool may apply the adjustment without any further input. In other examples, the method may further include a step of outputting an indication of the adjustment at the output of the fastener set tool. The method may further include a step of receiving user input at the input of the fastener set tool instructing the fastener set tool to apply the adjustment, and the adjustment may be applied in response to the user input. For example, the tool may determine that an adjustment should be applied and provide a display to the user of the tool. The user may instruct the tool to apply the adjustment based on input via the display or buttons.

[0206] In some examples, the adjustment may be applied after inserting the first fastener but before inserting the second fastener. In other words, the fastener setting tool may insert the first fastener with a first set of parameters and, based on the comparison, insert the second fastener with a second set of parameters. In other examples, the adjustment may be applied after inserting the first fastener but before further inserting the first fastener. In other words, the fastener setting tool may insert the first fastener with a first set of parameters and, based on the comparison, further insert the first fastener with a second set of parameters. To put it another way, the adjustment may be applied while the first fastener is inserted.

[0207] As mentioned above, Method 800 may be iterative. For example, each step of Method 800 may be repeated sequentially until there is a change in the determined characteristic (such that the result of the comparison between the determined characteristic and the predetermined characteristic is different). At this point, the tool may be determined to be not requiring any further adjustment (similar to step 904 of Method 900, described later). Alternatively, a second adjustment may be calculated and applied. The second adjustment may be the opposite of the latest adjustment applied. In other words, the second adjustment may be opposite to the latest adjustment and of the same magnitude. For example, if the latest adjustment was a 2kN reduction in the force applied to the tool, the second adjustment may increase the force applied to the tool by 2kN. Beneficially, the tool may be able to find the optimal parameters (at a given level of granularity in the parameters) necessary to achieve a particular head height (or other parameters).

[0208] Furthermore, a third adjustment may be applied. The third adjustment may be opposite to the second adjustment (i.e., in the same direction as the first adjustment). The third adjustment may be smaller in magnitude than the first adjustment. For example, the first adjustment may be +2kN, the second adjustment may be -2kN, and the third adjustment may be +0.5kN. In this way, additional iterations of method 800 can be performed using a step of reducing the size so that the optimal parameter required to achieve a particular head height (or other parameter) is needed (by increasing the level of granularity in the parameter).

[0209] As an alternative to the aforementioned second adjustment, the second adjustment may be opposite to the most recent first adjustment and have a smaller magnitude than the most recent first adjustment. For example, if the most recent adjustment was a reduction of 2 kN in the force applied to the tool, the second adjustment may increase the force applied to the tool by 0.5 kN. In other words, the first adjustment may be -2 kN and the second adjustment may be +0.5 kN. In this way, the method can be continued until the magnitude of the adjustment matches a specific grit size to which the tool can be adjusted.

[0210] As an example of Method 800, the rivet setting tool can insert a first fastener with a force of 85kN to achieve a head height of 0.0mm (i.e., the fastener may be flush). Thus, the tool can reduce the applied force by 2kN. These steps may be repeated, and subsequent fasteners may be inserted with forces of 83kN, 81kN, 79kN, and 77kN, respectively, with each subsequent fastener having a head height of 0.0mm. The force can be reduced to 75kN, and fasteners inserted with this force may have a head height of 0.1mm. The latest adjustment may then be reversed, and the tool may then insert a fastener with a force of 77kN to a head height of 0.0mm. In this way, the minimum force required to insert a fastener to a specific head height on the workpiece can be found.

[0211] The method may further include storing determined parameters, predetermined parameters, adjustments, and / or determined parameters of subsequent fasteners. The stored values ​​can be analyzed to determine or predict whether defects exist.

[0212] It will be understood that the steps of method 800 may be performed in any order. For example, method 800 may begin with step 803, which applies adjustments to the parameters.

[0213] Figure 9 is a flowchart illustrating how to determine if adjustments are necessary for a fastener set tool and / or workpiece. In step 901, the determined characteristics are compared to predetermined characteristics. In step 904, it is determined that no adjustments are necessary.

[0214] The determined characteristics can be compared with predetermined characteristics in a manner similar to that of method 800. In other words, step 901 can be performed in a manner similar to that of step 801.

[0215] In step 904, it is determined that no adjustment is necessary. As previously mentioned in relation to step 801, comparing the determined characteristic with a predetermined characteristic may include applying a threshold to the difference. That is, if the difference is below the threshold, it can be determined that no adjustment is necessary for the tool.

[0216] Figure 10 is a flowchart illustrating iterative method 1000 for calculating and applying adjustments to a fastener set tool and / or workpiece. Iterative method 1000 is an example of how methods 800 and 900 can be performed iteratively.

[0217] In step 1011, the first determined characteristic is compared with the first predetermined characteristic. In step 1012, the first adjustment is calculated. In step 1013, the first adjustment is applied. In step 1021, the second determined characteristic is compared with the second predetermined characteristic. In step 1022, it is determined which second adjustment is needed. In step 1023, the second adjustment is applied. Alternatively, in step 1024, no second adjustment is applied.

[0218] Each step of iterative method 1000 can be performed in the same way as the corresponding steps of methods 800 and 900. Determining which second adjustment is necessary (i.e., step 1022) can be performed in the same way as calculating the adjustment in step 802 and / or determining in step 904 that no adjustment is necessary. That is, if the difference between the second determined characteristic and the second predetermined characteristic is below a threshold, the second adjustment may not be applied. Alternatively, if the difference between the second determined characteristic and the second predetermined characteristic is above a threshold, the second adjustment may be applied. As previously mentioned in relation to method 800, the size of the second adjustment may depend on the difference. Alternatively, the size of the second adjustment may be independent of the difference.

[0219] It will be understood that the use of “First” and “Second” in relation to Method 1000 is a label. In other words, there may be any number of “First” adjustments.

[0220] In this specification, terms such as “downward” or “upper” are used, but it should be understood that such terms are illustrative and do not imply that a particular orientation of the device is mandatory. For example, the rivet setting tool 2 shown in Figure 1 operates on a substantially flat workpiece W aligned with the horizontal plane, but the rivet setting tool 2 may operate on a workpiece W aligned in a different manner.

[0221] The threshold tests (and corresponding operations) described herein (i.e., those described in relation to Methods 200, 400, and 500) are merely illustrative, and it will be understood that other combinations (including other threshold tests for other determined values) may be preferred.

[0222] The steps of the methods described herein (i.e., Method 200, Method 400, etc.) are described in order, but the order is not a requirement of the present invention. For example, in Method 200, the position of the calibration position may be measured (in Step 202) after the position of the surface of the workpiece 330 is measured (in Step 204).

[0223] Although the steps of the methods described herein have been described as being performed, one or more of the methods may be performed as computer implementation methods. For example, one or more of the methods may be stored in a computer-readable storage medium that, when read by a computer, causes a computer-controlled fastener set tool 310 to perform one or more of the methods. The computer may be referred to as a controller. In computer implementation methods, it will be understood that operations may be described as being performed (instead of being performed). For example, in method 200, step 201 is to advance the blank holder to the calibration position. In computer implementation methods, the corresponding step may be to advance the blank holder to the calibration position.

[0224] Hereinafter, references to receiving a quantity, determining a quantity, or measuring a quantity will be interpreted similarly. For example, receiving a determined position of the upper end face of a fastener may include determining the position of the upper end face of a fastener and / or measuring the position of the upper end face of a fastener.

[0225] It will be understood that a reference to the energy applied to a fastener by a rivet insertion tool can similarly refer to the force applied to the fastener by the rivet insertion tool. Some rivet insertion tools are known to operate by the application of torque. A reference to energy (applied by a rivet insertion tool) can similarly refer to the corresponding torque. Similarly, it will be understood that a force sensor may alternatively be called an energy sensor or a torque sensor (and vice versa).

[0226] Figure 11 shows an exemplary computer system 1100. The computer implementation method 100 (or any other method described herein) can be implemented on a computer system such as computer system 1100. Computer system 1100 may include a central processing unit 1110, a memory 1120, one or more storage devices 1130, an input / output processor 1140, and circuits connecting the components 1050 and one or more input / output devices 1160.

[0227] In this specification, the term “configured” is used in relation to system and computer program components. A system of one or more computers being configured to perform a particular operation or action means that software, firmware, hardware, or a combination thereof is installed on the system that causes the system to perform the operation or action during operation. A system of one or more computer programs being configured to perform a particular operation or action means that the program, when executed by data processing, contains instructions that cause a device to perform the operation or action.

[0228] The subject matter and functional embodiments described herein can be implemented in digital electronic circuits, tangibly embodied computer software or firmware, computer hardware including the structures disclosed herein and their structural equivalents, or one or more combinations thereof. Embodiments of the subject matter described herein can be implemented as one or more modules of computer programs, i.e., computer program instructions encoded on a tangible non-temporary storage medium for execution by a data processing device or for controlling the operation of a data processing device. The computer storage medium can be a machine-readable storage device, a machine-readable storage board, a random-access or serial-access memory device, or one or more combinations thereof. Alternatively or additionally, the program instructions can be encoded on artificially generated propagating signals, such as machine-generated electrical signals, optical signals, or electromagnetic signals, which are generated to encode information for transmission to a suitable receiving device for execution by a data processing device.

[0229] The term "data processing device" refers to data processing hardware and encompasses all kinds of devices, machines, and equipment for processing data, including, for example, programmable processors, computers, or multiple processors or computers. A device may also be, or further include, dedicated logic circuits such as FPGAs (Field-Programmable Gate Arrays) or ASICs (Application-Specific Integrated Circuits). Optionally, in addition to hardware, a device may include code that constitutes the execution environment for computer programs, such as processor firmware, protocol stacks, database management systems, operating systems, or one or more combinations thereof.

[0230] Computer programs, also called or written as programs, software, software applications, applications, modules, software modules, scripts, or code, can be written in any form of programming language, including compiled or interpreted languages, or declarative or procedural languages, and can be deployed in any form, such as as standalone programs or as modules, components, subroutines, or other units suitable for use in a computing environment. A program may, but does not have to, correspond to a file in a file system. A program may be part of a file that holds other programs or data, for example, one or more scripts stored in a markup language document, a single file dedicated to the program in question, or multiple coordinated files, for example, a file that stores one or more modules, subprograms, or parts of code. A computer program can be deployed to run on one computer, or on multiple computers located in one site, or distributed across multiple sites and interconnected by data communication network pieces.

[0231] The processes and logic flows described herein can be executed by one or more programmable computers running one or more computer programs to perform functions by manipulating input data and generating outputs. The processes and logic flows can also be executed by dedicated logic circuits such as FPGAs or ASICs, or by a combination of dedicated logic circuits and one or more programmed computers.

[0232] A computer suitable for running computer programs can be based on a general-purpose or dedicated microprocessor, or both, or any other type of central processing unit. Generally, the central processing unit receives instructions and data from read-only memory or random access memory, or both. Essential elements of a computer are a central processing unit for executing or running instructions, and one or more memory devices for storing instructions and data. The central processing unit and memory can be complemented by or incorporated into dedicated logic circuits. Generally, a computer also includes one or more mass storage devices for storing data, such as magnetic, magneto-optical disks, or optical disks, or is operablely coupled to them to receive data from them, transfer data to them, or both. However, a computer is not required to have such devices. Furthermore, a computer can be embedded in another device, for example, a mobile phone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device, such as a Universal Serial Bus (USB) flash drive.

[0233] Computer-readable media suitable for storing computer program instructions and data include all forms of non-volatile memory, media, and memory devices, such as semiconductor memory devices including EPROM, EEPROM, and flash memory devices, magnetic disks such as internal hard disks or removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks.

[0234] To provide user interaction, embodiments of the subject matter described herein can be implemented on a computer having a display device for displaying information to the user, such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, and a keyboard and pointing device, such as a mouse or trackball, on which the user can provide input to the computer. User interaction can also be provided using other types of devices. For example, the feedback provided to the user can be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback. Input from the user can be received in any form, including acoustic, voice, or tactile input. Furthermore, the computer can interact with the user by sending documents to and receiving documents from a device used by the user, for example, by sending a web page to a web browser on the user's device in response to a request received from a web browser. The computer can also interact with the user by sending text messages or other forms of messages to a personal device, such as a smartphone running a messaging application, and receiving response messages from the user in return.

[0235] Data processing devices for implementing machine learning models may also include, for example, dedicated hardware accelerator units for handling the common computationally intensive parts of machine learning training or production, namely inference and workpiece loading.

[0236] Machine learning models can be implemented and deployed using machine learning framework pieces, such as the TensorFlow framework piece, the Microsoft Cognitive Toolkit framework piece, the Apache Singa framework piece, or the Apache MXNet framework piece.

[0237] Embodiments of the subject matter described herein can be implemented in a computing system including, for example, a backend component such as a data server, or a middleware component such as an application server, or a frontend component such as a client computer having a graphical user interface, a web browser, or an application that allows a user to interact with the implementation of the subject matter described herein, or in any combination of one or more such backend, middleware, or frontend components. The components of the system can be interconnected by digital data communications in any form or medium, such as communication network pieces. Examples of communication network pieces include local area network pieces (LANs) and wide area network pieces (WANs), such as the Internet.

[0238] A computing system can include clients and servers. Clients and servers are generally remote from each other and typically interact via a communication network. The relationship between the client and server arises from computer programs running on each computer that have a client-server relationship with each other. In some embodiments, the server sends data, such as an HTML page, to a user device for the purpose of displaying data to a user interacting with a device acting as a client and receiving user input from the user. Data generated on the user device, such as the results of user interactions, can be received by the server from the device.

[0239] This specification includes many specific details of implementation, which should not be construed as limitations on the scope of any invention or claim, but rather as descriptions of features that may be specific to a particular embodiment of a particular invention. Certain features described herein in the context of a separate embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any suitable partial combination in multiple embodiments. Furthermore, features described above as acting in a particular combination may be initially claimed as such, but one or more features from a claimed combination may, in some cases, be removed from the combination, and the claimed combination may cover a partial combination or a variation of a partial combination.

[0240] Similarly, while the operations are shown in the drawings and described in the claims in a specific order, this should not be understood as requiring that such operations be performed in a specific order shown, or in a sequential order, or that all illustrated operations be performed, in order to achieve the desired result. In certain circumstances, multitasking and parallel processing may be preferable. Furthermore, the separation of various system modules and components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged in multiple software products.

[0241] Specific embodiments of the subject matter are described. Other embodiments are within the scope of the following claims. For example, the operations described in the claims can be performed in a different order and still achieve the desired results. As an example, the processes shown in the accompanying drawings do not necessarily require the specific order or sequence shown to achieve the desired results. In some cases, multitasking and parallel processing may be preferable.

Claims

1. A computer implementation method for determining the characteristics of a fastener, The steps include receiving a stored deflection coefficient, relating the stored deflection coefficient to the peak force exerted on the die by the fastener, The determined peak force is received, and the determined peak force corresponds to the peak force exerted on the fastener by the punch of the fastener set tool, Steps include receiving the determined thickness of the workpiece, The steps include receiving the determined position of the upper end surface of the fastener, The head height HH of the fastener is determined as follows: [Math 1] During the ceremony, DF is the stored deflection coefficient, PF is the peak force determined above, MT is the determined thickness of the workpiece, ED is the determined position on the upper end surface of the fastener. Steps and Computer implementation methods, including those mentioned above.

2. The step of receiving the determined thickness of the workpiece is The process of moving the blank holder of the fastening tool set forward so that the blank holder moves to the calibration position, A step of measuring the position of the calibration position along the axis moved by the blank holder using a first sensor configured to measure the displacement of the blank holder, A step of advancing the blank holder so that the blank holder contacts the surface of the workpiece and clamps the workpiece against the die, A step of measuring the position of the surface of the workpiece along the axis moved by the blank holder using the first sensor, A step of determining the thickness of the workpiece using the measured position of the calibration position and the measured position of the surface of the workpiece, The computer implementation method according to claim 1, further comprising:

3. A step of applying a threshold test to the head height determined above, A computer implementation method according to claim 1 or 2, further comprising:

4. A computer implementation method for determining the characteristics of a workpiece and / or a set of fasteners and tools, The steps include: advancing the blank holder of the fastening tool set so that the blank holder moves to the calibration position; A step of measuring the position of the calibration position along the axis moved by the blank holder using a first sensor configured to measure the displacement of the blank holder, The steps include: advancing the blank holder so that it contacts the surface of the workpiece and clamps the workpiece against the die; A step of measuring the position of the surface of the workpiece using the first sensor, A step of determining the thickness of the workpiece using the measured position of the calibration position and the measured position of the surface of the workpiece, Computer implementation methods, including those mentioned above.

5. The steps include receiving the determined position of the upper end surface of the fastener, A step of receiving the measured head height of the fastener, The tool deflection TD corresponding to the change in the end position relative to the starting position of the tool component caused by the insertion of the fastener is determined as follows: [Math 2] During the ceremony, HH is the measured head height of the fastener, MT is the determined thickness of the workpiece, ED is the determined position on the upper end surface of the fastener. Steps and The computer implementation method according to claim 4, further comprising:

6. The computer mounting method according to claim 5, further comprising the step of storing the determined tool deflection.

7. A step of determining the peak force applied to the fastener by the punch, The deflection coefficient DF corresponding to the deflection of the fastener set tool with respect to the peak force exerted on the fastener by the punch is determined as follows: [Math 3] In the formula, PF is the determined peak force, and the step and The computer implementation method according to claim 5 or 6, further comprising:

8. The computer implementation method according to claim 7, further comprising the step of storing the deflection coefficient.

9. A computer implementation method according to any one of claims 4 to 8, further comprising the step of applying a threshold test to the determined characteristics.

10. A computer-based method for determining the characteristics of a workpiece or a joint formed on the workpiece, The steps include bringing the blank holder of the fastening tool set into contact with the surface of the workpiece, The steps include: applying force to the blank holder in the axial direction toward the workpiece; The steps include detecting the movement of the workpiece by measuring the displacement of the blank holder, The steps include determining the characteristics of the workpiece or the joint formed on the workpiece based on the detected movement, Computer implementation methods including

11. The computer implementation method according to claim 10, further comprising the step of applying a threshold test to the determined characteristics.

12. The computer mounting method according to claim 10 or 11, further comprising the step of inserting a first fastener into the workpiece using the punch of the fastener set tool.

13. The computer mounting method according to any one of claims 3, 9, or 11, further comprising the step of determining, based on the results of the threshold test, that the fastener set tool requires maintenance.

14. A computer mounting method according to any one of claims 3, 9, 11, or 13, further comprising the step of determining, based on the results of the threshold test, that the workpiece should be inspected and / or replaced.

15. A computer implementation method according to any one of claims 3, 9, 11, 13, or 14, further comprising the step of determining that, based on the results of the threshold test, parameters associated with the fastener set tool should be adjusted.

16. The step of measuring the displacement of the blank holder is, A step of measuring the displacement of the components of the fastener set tool that are fixed to the blank holder, A computer implementation method according to any one of claims 2 to 15, including the method described in any one of claims 2 to 15.

17. The steps include comparing the determined characteristics with predetermined characteristics, and determining that the difference between the determined characteristics and the predetermined characteristics represents the state of the fastener set tool or the workpiece, A step of calculating an adjustment based on the comparison in order to compensate for the condition of the fastener set tool or the workpiece, The steps of applying the adjustment to the fastener set tool and / or the workpiece, A computer implementation method according to any one of claims 1 to 16, further comprising:

18. The steps of comparing the determined characteristics with the predetermined characteristics, calculating the adjustment based on the comparison, and applying the adjustment are each performed after inserting the first fastener into the workpiece using the punch, and the method is The computer mounting method according to claim 17, dependent on claim 12, further comprising the step of inserting a second fastener into the workpiece using the punch after the adjustment has been applied.

19. The steps of comparing the determined characteristics with the predetermined characteristics, calculating the adjustment based on the comparison, and applying the adjustment are each performed after inserting the first fastener into the workpiece using the punch, and the method is A computer mounting method according to claim 17, dependent on claim 12, further comprising the step of further inserting the first fastener into the workpiece using the punch after the adjustment has been applied.

20. The computer mounting method according to any one of claims 17 to 19, wherein the adjustment is an adjustment to the torque and / or force applied by the fastening set tool.

21. The computer implementation method according to any one of claims 17 to 19, wherein the adjustment is an adjustment to the speed of the fastening set tool.

22. Steps include: comparing the determined characteristics with predetermined characteristics, and determining that the difference between the determined characteristics and the predetermined characteristics represents the state of the fastener set tool and / or the workpiece; Based on the comparison, the step of determining that no adjustment is required to the fastener set tool and / or the workpiece, A computer implementation method according to any one of claims 1 to 16, further comprising:

23. A computer mounting method according to any one of claims 17 to 22 dependent on claim 1, wherein the determined characteristic is the determined head height of the first fastener, and the predetermined characteristic is the predetermined head height.

24. A computer mounting method according to any one of claims 17 to 22 dependent on claim 4, wherein the determined characteristic is the determined thickness of the workpiece, and the predetermined characteristic is the predetermined thickness.

25. A computer mounting method according to any one of claims 17 to 22 dependent on claim 5, wherein the determined characteristic is a determined tool deflection, and the predetermined characteristic is a predetermined tool deflection.

26. A computer mounting method according to any one of claims 17 to 22 dependent on claim 7, wherein the determined characteristic is a determined deflection coefficient, and the predetermined characteristic is a predetermined deflection coefficient.

27. A computer implementation method for determining the force required to insert a fastener into a workpiece using a fastener set tool, A step of receiving the required head height of the fastener, Steps to receive the thickness of the workpiece, Steps to receive the deflection coefficient, The steps include receiving the desired position on the upper end surface of the fastener, The force PF to be applied to the fastener by the punch of the fastener set tool is determined as follows: [Math 4] During the ceremony, HH is the required head height of the fastener, DF is the aforementioned deflection coefficient, MT is the thickness of the workpiece, ED is the position of the upper end surface of the fastener. Steps and Computer implementation methods, including those mentioned above.

28. A fastener set tool configured for use in the computer implementation method described in any one of claims 1 to 27.

29. A controller for a fastener set tool, configured to perform the computer implementation method described in any one of claims 1 to 27.

30. A fastening tool set comprising a first sensor configured to measure the displacement of a blank holder.

31. The fastening tool set according to claim 30, further comprising a member fixed to the blank holder, wherein the first sensor is configured to measure the displacement of the member.

32. The fastening tool set according to claim 30 or 31, wherein the first sensor is a contact displacement sensor.

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