Self-piercing clinch fastener installation press

Abstract

A fastener clinching press includes a frame supporting a die having a hole that engages the fastener to produce a slug from the workpiece. A punch has a head assembly that engages the fastener. A first sensor determines a punch position relative to the die. A pin is slidably mounted within the head assembly and extends from the head assembly to a tip that positions a fastener relative to the die. The pin is movable between a plurality of pin positions, including a slug ejection position. A second sensor is disposed within the head assembly and operatively connected to the pin. The sensor monitors the plurality of pin positions related to a pin travel signature.A controller communicates with the first and second sensors and determines a result of the clinching operation based on the punch position and the pin travel signature.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application No. 63 / 425,447, filed November 15, 2022. TECHNICAL FIELD

[0002] The present disclosure relates to a clinching press for securing a fastener (e.g., a nut) to a workpiece, such as a metal sheet. More specifically, the present disclosure relates to a head assembly for pressing the fastener while detecting the position of the fastener, and a feeder for loading the head assembly with the fastener. BACKGROUND

[0003] Clinching presses are used to secure clinch fasteners to metal objects such as automotive body panels. A fastener, such as a nut, is loaded onto a head assembly. The head assembly moves to press a fastener against the sheet metal until the sheet metal engages a die with sufficient pressure to pierce and mechanically lock the fastener into the sheet metal.

[0004] Loading the fastener into the clinching press head assembly is typically an automated process, minimizing fastener loading time, improving process reliability, and reducing pinch point hazards. Occasionally, the fastener is not loaded into the head assembly properly, or the fastener is not loaded into the head assembly at all. When an operator positions a sheet metal part for fastener application, the operator can visually detect fault conditions before or after the clinching press installation cycle.

[0005] Sensors were used in an effort to determine the presence and orientation of the fastener in the clinching press. Additional switches or sensors were used to detect the position of the ram and ensure that the clinching press was closed. Typically, a linear variable differential transformer (LVDT) was connected to an outer side of a ram that supports the head assembly to measure the movement of the head assembly. When no nut is present, the head assembly moves a greater amount than when a fastener is present and in the correct orientation. When the fastener is not correctly aligned, the head assembly moves slightly less than with a correctly aligned fastener. In this way, the presence and orientation of the fastener were detected.However, it was difficult to accurately capture the correct orientation of the fastener, especially with increasing automation speed. SUMMARY OF THE INVENTION

[0006] In an exemplary embodiment, in a clinching press for performing a clinching operation for securing a fastener to a workpiece, the fastener clinching press includes a frame supporting a die having a hole configured to cooperate with the fastener to produce a waste piece from the workpiece. A punch has a head assembly configured to engage the fastener. A first sensor is configured to determine a punch position relative to the die. A pin is slidably mounted within the head assembly and projects from the head assembly to a tip configured to position a fastener relative to the die, the pin being movable between a plurality of pin positions, including a waste piece ejection position.A second sensor is disposed in the head assembly and operatively connected to the pin, the sensor configured to monitor the plurality of pin positions relative to a pin travel signature. A controller is in communication with the first and second sensors, the controller configured to determine a result of the clinching operation based on the punch position and the pin travel signature.

[0007] In a further embodiment of any of the preceding embodiments, the head assembly includes a cavity, and the pin is slidable within the cavity and includes a stop. A spring is disposed within the cavity and cooperates with the stop to bias the pin to a fully extended position.

[0008] In a further embodiment of any of the above embodiments, the punch comprises a cylinder, the head assembly comprises a head having a bore that slidably receives the pin, and a body operatively attached to the cylinder. The head is operatively secured to the body to enclose the cavity.

[0009] In a further embodiment of any of the above embodiments, the second sensor is a linearly variable differential transformer having a core attached to the stop for determining the movement of the pin therewith.

[0010] In a further embodiment of any of the preceding embodiments, the head assembly includes a magnet configured to hold the fastener in engagement with the head assembly during the clinching process.

[0011] In a further embodiment of any of the preceding embodiments, the clinching press includes a fastener feeder having a carriage with one end configured to receive a fastener. The carriage is mounted to a carriage cylinder configured to move the carriage between an extended carriage position and a retracted carriage position. A lift cylinder is configured to pivot the carriage cylinder between a first position configured to space the fastener from the head assembly and a second position configured to engage the fastener with the head assembly.

[0012] In a further embodiment of any of the above embodiments, the first sensor is a switch.

[0013] In a further embodiment of any of the preceding embodiments, the clinching press includes a fastener proximity sensor disposed in the head assembly on a surface of the head assembly configured to support the fastener during the clinching operation.

[0014] In a further embodiment of one of the above embodiments, the clinching press has a waste piece exit sensor connected to the hole. The waste piece exit sensor is connected to the controller. The controller is configured to detect the passage of the waste piece with the waste piece exit sensor.

[0015] In a further embodiment of any of the above embodiments, the assembly chamber comprises a multi-axis robot configured to move the workpiece to and from the clinching press for the clinching process.

[0016] In a further embodiment of any of the above embodiments, the assembly chamber comprises a conveyor configured to feed the workpiece to the multi-axis robot.

[0017] In another exemplary embodiment, in a clinching press for performing a clinching operation for securing a fastener to a workpiece, the fastener clinching press includes a frame, a ram movable relative to the frame and having a head assembly configured to engage the fastener, and a fastener feeder having a carriage with an end configured to receive a fastener. The carriage is mounted to a carriage cylinder configured to move the carriage between a retracted carriage position and an extended carriage position in which the fastener is disposed below the head assembly.A lifting cylinder is configured to pivot the carriage in the extended position between a first position configured to position the fastener at a distance from the head assembly and a second position configured to position the fastener in engagement with the head assembly.

[0018] In a further embodiment of any of the preceding embodiments, the clinching press includes a pin slidably mounted in the head assembly and extending from the head assembly to a tip configured to position a fastener. The pin is movable between a plurality of pin positions. A sensor is disposed in the head assembly and operatively connected to the pin. The sensor is configured to monitor the plurality of pin positions. A controller is in communication with the sensor. The controller is configured to determine a result of the clinching operation based on the plurality of pin positions.

[0019] In a further embodiment of any of the preceding embodiments, the carriage has one end with a pocket configured to receive the fastener from a chute. A fastener proximity sensor is attached to the fastener feeder and configured to detect the presence of the fastener in the pocket.

[0020] In a further embodiment of any of the preceding embodiments, the head assembly includes a magnet configured to maintain the fastener engaged with the head assembly after the carriage has moved from the second position back to the first position.

[0021] In a further embodiment of any of the preceding embodiments, the clinching press includes a fastener proximity sensor disposed in the head assembly on a surface of the head assembly configured to support the fastener with the carriage returned to the second position.

[0022] In another exemplary embodiment, a method for clinching a fastener to a workpiece includes positioning a fastener under a head assembly, magnetically holding the fastener to the head assembly with a pin extending into and engaging the fastener, advancing the head assembly toward a die, engaging a workpiece between the die and the head assembly to pierce the workpiece with the fastener during a clinching operation, and measuring the movement of the pin with a sensor located within the head assembly to monitor the clinching operation.

[0023] In a further embodiment of any of the above embodiments, the sensor is a pin sensor and a step of detecting a position of the head assembly with a punch sensor during the feeding step is provided.

[0024] In a further embodiment of any of the preceding embodiments, the positioning step comprises pivoting a carriage toward the head assembly, thereby triggering the magnetically retaining step.

[0025] In a further embodiment of the above embodiments, the method includes a step of detecting the presence of the fastener on the head assembly with a proximity sensor within the head assembly during the magnetically retaining step. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The disclosure can be better understood from the following detailed description when taken in conjunction with the accompanying drawings, in which: Fig. 1 a schematic view of a chamber with at least one clinching press according to the disclosed embodiments. Fig.2A to 2C are perspective, front and side cross-sectional views of an exemplary clinching press, respectively. Fig. 3A and Fig. 3B is a perspective and enlarged cross-sectional view of a head assembly, a die, and a fastener feeder. Fig. 4 a control scheme of the Fig. 1 shown chamber. Fig. 5A and Fig. 5B is a side view and a cross-sectional view of the head assembly and the feeder. Fig. 6A to 6C are cross-sectional views of the feeder in an extended position relative to the head assembly in a pre-loading position, a loading position, and an unloaded position, respectively. Fig. 7A and Fig. 7B the condition with an incorrectly loaded or unloaded fastener. Fig.8A to 8Q are cross-sectional views of the head assembly relative to the die in various states that can be detected with the disclosed sensor configuration.

[0027] The embodiments, examples, and alternatives of the preceding paragraphs, the claims, or the following description and drawings, including their various aspects or respective individual features, may be used independently of one another or in any combination. Features described in connection with one embodiment apply to all embodiments, unless these features are inconsistent. Like reference numerals and designations in the various drawings indicate like elements. DETAILED DESCRIPTION

[0028] The disclosed system provides cost-effective automation for clinching fasteners on sheet metal stampings or other materials at high speeds.

[0029] A fastener clinching system 10 is in Fig. 1 schematically shown. A first and a second conveyor 12a, 12b feed various parts, such as stamped parts, to a robot 14 within a chamber 15. The robot 14 transfers the parts from the conveyors 12a, 12b to clinching presses 16a, 16b (generally clinching press 16). One clinching press 16a secures a fastener fed from a vibrating feed hopper 17a, and the other clinching press 16b secures nuts fed from a vibrating feed hopper 17b (generally vibrating feed hopper 17). The Fig. The chamber arrangement shown in Figure 1 is merely exemplary and may be designed differently than shown, for example with fewer or more operations, which may include operations other than clinching.

[0030] With reference to Fig.2A, a fastener clinching monitor 41 is connected to a controller 39 which is in communication with various disclosed sensors (see, for example, Fig. 4). The sensors track movements of components on the clinching press 16 related to the movement of the fastener throughout the clinching process. The sensor data is used to determine useful information about the clinching process, as will be apparent from the following description. A monitor programming interface is connected to the fastener clinching monitor 41, and its data is analyzed, for example, using statistical analysis software.

[0031] With reference to the Fig.2A to 2C, the clinching press 16 comprises a frame 20 carrying a linearly movable punch 22, which serves to press a fastener F against a die 28 into a workpiece W under high forces in order to clinch the fastener F onto the workpiece W, which is usually a sheet metal. During the clinching process, the fastener F pierces a hole in the workpiece W and creates a waste piece S, which is ejected (see Fig. 8G). As the workpiece W is pierced with the fastener F, the waste piece S moves through a hole 37 in the die 28 and is collected in a basket 38. A waste piece sensor 48 may be used to detect the waste piece S as it passes through the hole 37, thereby confirming that the waste piece S has become detached from the workpiece W.

[0032] A head assembly 24 is attached to one end of the punch 22, which is typically positioned above the die 28 supported on the frame 20. The head assembly 24 is provided with a head 26, which serves as the upper die and engages and holds the fastener F. The fastener F is loaded onto the head 26 by a feeder 36, which receives correctly aligned fasteners F from the vibratory feed hopper 17. All of these operations occur at relatively high speed and must be performed with precise reproducibility. Because many sources of error exist due to the complexity and speed of the fastener clinching process, it is desirable to design the system 10 to be as error-free as possible. However, previous efforts at error prevention and monitoring have been inadequate for a production environment.

[0033] In operation, the ram 22 is actuated by a cylinder 30, which is supplied with compressed air from an air source 32 via an accumulator 34. The cylinder 30 may, for example, be an air-over-oil booster cylinder. A control valve 31 selectively supplies air to the cylinder 30 to extend and retract the ram 22 in response to a command from the controller 39 ( Fig. 4). A punch sensor 40, a linear variable differential transformer (LVDT), is typically mounted externally on the frame 20 and connected to the outside of the head assembly 24 to monitor the stroke of the punch 22. Traditionally, this punch sensor 40 was used to provide overall monitoring of whether a clinching operation was successfully completed or whether an error occurred during the attempted clinching operation.

[0034] The feeder 36 is loaded with fasteners F from the vibratory feed container 17 and must deliver these fasteners F individually to the head 26. The feeder 36 positions the fastener to be loaded onto the head 26 for subsequent engagement with the workpiece W. With reference to the Fig. 3A to 3B, the feeder 36 is mounted on a bracket 50 that is attached to the frame 20. The feeder 36 includes a chute 52 that conveys fasteners from the vibratory feed container 17 to one end 62 of a carriage 60. The end 62 has a pocket 64 ( Fig. 5B) that receives a fastener F from the chute 52. A proximity sensor 58 may be provided relative to the feeder 36 to ensure that a fastener F has actually been properly loaded into the pocket 64.

[0035] The feed device 36 has a feed carriage cylinder 54 which, as shown in Fig. 4, is pneumatically actuated by a valve 55. The slide cylinder 54 moves the slide 60 between the positions shown in the Fig. 5A and Fig. 5B shown retracted positions (ie the first position) and those shown in the Fig. 6A to 6C. When the feed device 36 is in the retracted position, a valve 57 ( Fig. 4) actuated lifting cylinder 56 in a retracted position.

[0036] In one example, the head assembly 24 secures the head 26 to a body 66 with a nut 68 to facilitate assembly and disassembly for maintenance and replacement of wear parts. The head 26 may, if desired, be secured to the body 66 with bolts (not shown) instead of the large nut 68. A pin 44 (or "stripper pin") extending to a tip 45 is slidably received in the head 26 such that the tip 45 projects from the head 26 to retain the fastener F against a surface of the head 26 ( Fig.6B). A pin sensor 46 is disposed within the head assembly 24 and coupled to the pin 44. In one example, the pin sensor 46 is a linear variable differential transformer (LVDT) having a core 78 attached to a stop 74 provided on the pin. The stop 74 and the core 78 are disposed within a cavity 72 within the head assembly 24. A spring 76, such as a coil spring, is disposed within the cavity 72 and surrounds the core 78. The spring 76 biases the pin 44 to a normally fully extended position, which, during normal operation, serves to push the waste piece S through the die 28 and into the hole 37.

[0037] The pin 44 moves in a unique manner during operation, depending on the fastener loaded on the tip 45, the orientation and presence / absence of the fastener, the wear of the pressing components, and the quality of the clinching process (e.g., measurement of the lowering travel, which results in a clinch signature that includes both travel and speed).

[0038] One problem with a conventional LVDT sensor as the punch sensor 40 is its accuracy over the long stroke of the punch, as the LVDT sensor is unlikely to have sufficient resolution to detect fastener height and upset distances with an accuracy high enough to detect fastener problems and confirm the reliability of the installation process. The disclosed pin sensor 46 and associated pin 44 solve this problem.

[0039] As can be seen, the described pin sensor 44 provides greater accuracy with a much smaller pin stroke compared to the punch stroke, which also allows for the use of a simplified punch sensor 40. For example, it is possible to use a single position switch (e.g., a limit switch) as the punch sensor 40 to indicate that the punch 22 has been reset or is sufficiently closed to detect a pinch hazard condition. In one example, the punch sensor 40 is a high-precision sensor that only engages the punch in close proximity to the fastener installation position. The punch sensor 40 may be provided as part of a servo-electric actuator used as the cylinder 30, which can provide the punch positioning function without a separate, discrete punch position sensor.If the plunger sensor 40 is a simple switch (or multiple switches), the controller 39 can, in many cases, consider the travel time before making a decision to determine whether the plunger 22 has reached the plunger sensor 40 within the expected time. The additional integrated pin sensor 46 works in conjunction with the plunger sensor 40, significantly improving accuracy and functionality. For example, high-resolution data from both sensors 40, 46 facilitates the identification of specific conditions to facilitate automatic troubleshooting and process verification, as well as trend analysis, for example, for preventive maintenance.

[0040] The Fig.6A to 6C illustrate a fastener head loading sequence in which the fastener F is loaded onto the head 26 without the fastener F losing its engagement during its transport, thereby reducing the incidence of misloaded fasteners. Once the punch 22 has been raised after the previous clinching operation, the feeder 36 actuates the carriage 60 with the carriage cylinder 54 to an extended position (i.e., a second position, Fig. 6A to 6C) to position the end 62 and the fastener F held by it immediately below the head 26 in a "preloading position." The lift cylinder 56 is actuated to extend the carriage cylinder and pivot about a pivot point 65 ( Fig.5A) to raise the end 62 and engage the fastener F with the head 26 in a "loading position." The head 26 includes one or more magnets 71 (e.g., three or four discrete, circumferentially spaced magnets) that hold the fastener F against the head assembly 24 and centered with respect to the pin 44 when the lift cylinder 56 is retracted to move the end 62 downward to an "unloaded position."

[0041] The Fig. 7A and Fig. 7B show exemplary error conditions in which the fastener F is incorrectly loaded relative to the head assembly 24 ( Fig. 7A) or is not present ( Fig.7B). The sensor used to check whether the feeder 36 has been raised to deposit the fastener onto the pin 44 is usable for detecting a position error. The sensor that detects that the feeder has been raised to the correct position will trigger an error if the position cannot be reached. Examples include a misalignment between the feeder 36 and the pin 44, if the fastener (e.g., a nut) cannot be placed onto the pin 44, or if the fastener has shifted into an unacceptable orientation during the transfer movement. These conditions can be detected, for example, by detecting a pressure deviation in the lift cylinder 56 or by detecting an angular position of the carriage 60. A proximity sensor 70 ( Fig.5B) can, if desired, be integrated into the head 26 to check whether the fastener F has been loaded onto the head 26.

[0042] Once the fastener F has been loaded onto the head 26, the robot 14 positions the workpiece W between the fastener F and the die 28. The punch 22 is then lowered to engage the fastener F and the workpiece W under low pressure between the head 26 and the die 28. The pin position data is used to determine if the correct fastener and workpiece (stamping) are present before a high installation force is applied. Assuming no errors are detected, the punch 22 continues to advance under high pressure until the fastener F pierces the workpiece W, creating a separate waste piece S. Once the fastener is installed, the pin pushes the waste piece S created by the fastener into the die 28.This fully extended pin position is detected by the pin sensor 46 to determine that the waste piece S has indeed been released from the finished assembly. During clinching, a position / force signature can be used for further validation of the fastener and the installation process.

[0043] A typical clinching press operation is complex and performed at relatively high speeds. Therefore, it is desirable to detect both the successful completion of a clinching operation and numerous fault conditions that may occur. To this end, several disclosed sensors (e.g., the punch sensor 40 and the pin sensor 46) are integrated into the clinching press 16 to monitor the clinching operation, thus significantly improving the overall accuracy and functionality of the clinching press 16. Likewise, additional sensors (e.g., the scrap sensor 48, the feeder proximity sensor 58, and / or the head proximity sensor 70) may be integrated for further functionality and verification.

[0044] The pin position measurement enables high-resolution measurement of the process for detecting a variety of conditions, as shown in Table 1 below, based on a pin travel signature using the measured position of the pin 44 by the pin sensor 46.

[0045] Information from other sensors can also be used to provide additional data and improve fault detection and monitoring functionality. Clinch tool stripping pin Feeding device Recorded state sensor FIG . Stamp position Pen position Feeding device raised Postponed Fully extended Lowered Starting position X(Stamp reset switch at minimum) X Detection of the raised position would be an error 8A Postponed Not fully extended (or pushed out) Lowered Movement error of the stripper pin - collision (e.g. when loading the workpiece); clinching tool loose; stripper spring broken O X 8A (with pin movement) Postponed Not fully extended (or pushed out) Raised 1. Incorrect fastener (hole too small for stripper pin or fastener too thin) 2. Incorrect fastener (too small) or feeder not aligned with stripper pin O X X (Switch for raised position at minimum) 7B (with pen movement) Postponed Fully extended Not fully raised 1. Feeding device misaligned 2. Fastener too thick 3. Contamination on the stamp surface or fastener O X X (Switch for raised position at minimum) 7A Pushed forward with little force Fully extended N / A 1. No workpiece or fastening element present 2. No workpiece present ○ × 8B,8C Pushed forward with little force Pressed N / A No fastening element available O X 8D Pushed forward with little force Not fully extended or pressed N / A Workpiece and fastening element present O(minimum feed duration) X 8E,8F Pushed forward with little force Not fully extended or pressed N / A Workpiece present but fastener misaligned O(minimum feed duration) X 8Y, 8K, 8M Pushed forward with little force Not fully extended or pressed N / A No workpiece and fastener misaligned ○(Minimal feed time) × 8N,8O,8Q Pushed forward with little force Pressed on fastener thickness position * N / A Fastening element present O(minimum feed duration) X 8F Pushed forward with little force Pressed on wrong thickness position * N / A 1. Fastener upside down 2. Incorrect fastener thickness O(minimum feed duration) X 8I,8L,8P With clinch force advanced Before partially extending, pressed to the desired thickness * N / A Clinching successful and waste piece not cleanly removed (die button misaligned or worn; defective fastener) O (closed position of the switch for detecting low pressure at minimum) X 8H With clinch force advanced fully extended N / A Clinching successful and waste piece removed X(Punch feed switch at minimum) X 8G With clinch force advanced Fully pressed N / A no fastening element available X(Punch feed switch at minimum) X 8D * The detection of the position of the stripper pin must be used in conjunction with the detection of the upper punch stroke position. X = Required; minimum requirements given in parentheses O = Optional; minimum requirements given in parentheses

[0046] Because the sensor monitors pin 44 within head 26, the accuracy is far higher than when using external punch position switches or sensors, which are not sensitive enough to variations in workpiece and fastener thickness and where the punch stroke is increased by machine deflection. Because pin sensor 46 is integrated into clinching press 16, it is protected from damage and inaccessible to tampering. Furthermore, as described, the higher accuracy achieved by pin sensor 46 allows for a much simpler punch sensor 40.

[0047] It should also be understood that although a particular arrangement of components is disclosed in the illustrated embodiment, advantage may be taken in other arrangements. Although specific sequences of steps are shown, described, and claimed, it should be understood that the steps may be performed in any order, separately or in combination, unless otherwise indicated, and still obtain advantage of the present invention.

[0048] Although the various examples in the figures depict specific components, embodiments of this invention are not limited to these particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another of the examples.

[0049] Although an embodiment has been disclosed, those skilled in the art will recognize that certain modifications fall within the scope of the claims. Therefore, the following claims should be examined to determine their true scope and content. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 425,447

[0001]

Claims

[1] A clinching press for performing a clinching operation to secure a fastener to a workpiece, the fastener clinching press comprising: a frame supporting a die having a hole adapted to cooperate with the fastener to produce a waste piece from the workpiece, a punch having a head assembly configured to engage the fastener, a first sensor designed to determine a punch position relative to the die, a pin slidably mounted in the head assembly and extending from the head assembly to a tip configured to position a fastener relative to the die, the pin being movable between a plurality of pin positions, including a waste piece ejection position, a second sensor disposed in the head assembly and operatively connected to the pen, the sensor configured to monitor the plurality of pen positions with respect to a pen travel signature, and a controller in communication with the first and second sensors, the controller configured to determine a result of the clinching operation based on the punch position and the pin travel signature. [2] A clinching press according to claim 1, wherein the head assembly includes a cavity and the pin is slidable within the cavity and includes a stop, a spring disposed in the cavity and cooperating with the stop to bias the pin to a fully extended position. [3] A clinching press according to claim 2, wherein the punch comprises a cylinder, the head assembly comprises a head having a bore slidably receiving the pin, and a body operatively attached to the cylinder, and the head is operatively secured to the body to enclose the cavity. [4] Clinching press according to claim 2, wherein the second sensor is a linear variable differential transformer having a core which is attached to the stop for determining the movement of the pin therewith. [5] The clinching press of claim 1, wherein the head assembly includes a magnet configured to hold the fastener in engagement with the head assembly during the clinching operation. [6] A clinching press according to claim 1, comprising a fastener feed device comprising a carriage having an end configured to receive a fastener, the carriage being mounted on a carriage cylinder configured to move the carriage between an extended carriage position and a retracted carriage position, and a lift cylinder configured to pivot the carriage cylinder between a first position configured to position the fastener at a distance from the head assembly and a second position configured to position the fastener in engagement with the head assembly. [7] Clinching press according to claim 1, wherein the first sensor is a switch. [8] A clinching press according to claim 1, comprising a fastener proximity sensor disposed in the head assembly on a surface of the head assembly configured to support the fastener during the clinching operation. [9] Clinching press according to claim 1, comprising a waste exit sensor connected to the hole, wherein the waste exit sensor is connected to the controller and the controller is configured to detect a passage of the waste with the waste exit sensor. [10] An assembly chamber comprising the clinching press according to claim 1, wherein the assembly chamber comprises a multi-axis robot configured to move the workpiece to and from the clinching press for the clinching operation. [11] Assembly chamber according to claim 10, comprising a conveyor adapted to feed the workpiece to the multi-axis robot. [12] A clinching press for performing a clinching operation to secure a fastener to a workpiece, the fastener clinching press comprising: a frame, a punch movable relative to the frame having a head assembly configured to engage the fastener, and a fastener feeder comprising a carriage having an end configured to receive a fastener, the carriage being mounted on a carriage cylinder configured to move the carriage between a retracted carriage position and an extended carriage position in which the fastener is disposed beneath the head assembly, and a lift cylinder configured to pivot the carriage in the extended position between a first position configured to position the fastener at a distance from the head assembly and a second position configured to position the fastener in engagement with the head assembly. [13] Clinching press according to claim 12, comprising: a pin slidably mounted in the head assembly and extending from the head assembly to a tip configured to position a fastener, the pin being movable between a plurality of pin positions, a sensor disposed in the head assembly and operatively connected to the pin, the sensor configured to monitor the plurality of pin positions, and a controller in communication with the sensor, the controller configured to determine a result of the clinching operation based on the plurality of pin positions. [14] The clinching press of claim 12, wherein the carriage has one end with a pocket configured to receive the fastener from a chute, a fastener proximity sensor mounted on the fastener feeder and configured to detect the presence of the fastener in the pocket. [15] The clinching press of claim 12, wherein the head assembly includes a magnet configured to maintain the fastener engaged with the head assembly after the carriage has moved from the second position back to the first position. [16] A clinching press according to claim 15, comprising a fastener proximity sensor disposed in the head assembly on a surface of the head assembly configured to support the fastener with the carriage returned to the second position. [17] A method for clinching a fastener to a workpiece, comprising: Positioning a fastener below a head assembly, magnetically holding the fastener to the head assembly with a pin that extends into and engages the fastener, Advancing the head assembly towards a die, Engaging a workpiece between the die and the head assembly to pierce the workpiece with the fastener during a clinching operation, and Measuring the movement of the pin with a sensor located inside the head assembly to monitor the clinching process. [18] The method of claim 17, wherein the sensor is a pin sensor and it comprises a step of detecting a position of the head assembly with a punch sensor during the feeding step. [19] The method of claim 18, wherein the positioning step comprises pivoting a carriage toward the head assembly, thereby triggering the magnetically retaining step. [20] The method of claim 18, including a step of detecting the presence of the fastener on the head assembly with a proximity sensor within the head assembly during the magnetically retaining step.

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