Method and apparatus for detecting defects or deterioration in a tank side wall

Abstract

A method of detecting defects or deterioration in a side wall of a can body during production of the can body in a bodymaker. Each can body is formed by pushing a cup mounted on a punch of a reciprocating ram through one or more dies housed in a tool pack of the bodymaker. The method includes obtaining output signals from one or more eddy current sensors arranged around the ram axis and adjacent an exit end of the tool pack, processing the output signals to detect the passage of an open end of the can body side wall past the one or more sensors to determine a measure of the height or thickness of the can body side wall, and then analyzing the determined measure to identify defects or deterioration in the can body side wall.

Description

Technical Field

[0001] This invention relates to diagnostics for can-making machines. Specifically, this invention relates to a method and apparatus for monitoring the cans produced by a can-making machine. Background Technology

[0002] In known can-making machines that produce thin-walled two-piece metal cans using a "drawing and wall-ironing" (DWI) process, a metal cup is fed to the machine and carried by a punch at the end of a ram through a series of dies to produce a can of the desired size and thickness. This series of dies may include redrawing dies and one or more ironing dies, the redrawing dies used to reduce the diameter of the cup and lengthen its sidewalls, and the ironing dies used to iron the cup's can wall into the can. The area or bracket in the can-making machine frame where the dies are located is referred to as the "toolkit." The can carried by the punch may eventually contact a bottom forming tool or "domer," thereby forming a dome-like shape at the bottom of the can. An exemplary can-making machine is described in WO9934942.

[0003] Can-making machines typically operate at high speeds for extended periods, producing more than approximately 300 to 400 cans per minute. However, the quality of the produced cans can vary considerably over time due to changes such as: the alignment of machine parts, the temperature and flow rate of the coolant, the lubrication of the machine, and / or the quality of the incoming cups (e.g., due to variations in the quality of the metal coils used to make the cups).

[0004] In the DWI process, the metal is subjected to loads as the punch forces it through a thinning rolling die. However, the magnitude and distribution of these loads change during and between strokes, leading to variations in the quality of the produced can. For example, friction and general wear can cause slight changes in ram alignment over time. Furthermore, high-speed reciprocating rams are typically subjected to at least some vibration due to the impact of the ram on the can and the variable "sag" of the ram as it moves back and forth from its fully extended position.

[0005] For example, when the ram carrying the can comes into contact with the dome assembly, any misalignment can cause the can end to crack, especially if the can is made of aluminum. If the misalignment is slight, the crack may not be immediately visible to the naked eye (sometimes referred to as a "smile"), but once the can is filled, the crack can cause it to burst. This may not happen until a full can has been purchased.

[0006] Substandard cans can lead to waste and downtime in can production. This could be because the can-making machine itself must be recalibrated or repaired (which requires skilled operators), or because other machines on the production line are adversely affected by the substandard cans produced. Unfortunately, the high-speed, high-volume nature of the can-making industry means that lost production time can be very costly for manufacturers.

[0007] One type of can defect is a bent, untrimmed edge on the can body, often referred to as a "sugar spoon" because the can body resembles the bowl-shaped end of this type of vessel. Sugar spoon defects can occur in several ways: (i) the cup itself supplied to the can-making machine is bent (this defect can be amplified by the DWI process); (ii) the cup is not properly centered relative to the punch (e.g., because the punch is not aligned with the cup locator and / or the redrawing sleeve); (iii) the thinning calender die is misaligned relative to the punch, resulting in the can body's sidewalls being thinner on one side than the other; or (iv) the redrawing die and / or one or more thinning calender dies are damaged or worn.

[0008] In some cases, can defects can be so obvious that they cause mechanical failure, resulting in what is known as a "short can" or "tear," where a portion of the can remains as a fragment inside the can-making machine. Typically, can production must be halted until the fragment is removed to avoid damaging machine components or producing defective cans. Therefore, it is crucial to be able to diagnose can defects before such catastrophic failures occur.

[0009] One known method for assessing can quality involves pressing the arm of a mechanical measuring instrument against the edge of the can and rotating the can about its axis, causing the arm to displace to varying degrees depending on the height of the edge. While this method allows for precise measurement of the can, it is too slow to measure every single can produced and requires periodic removal of cans from the production line (sampling). Therefore, problems may go undiagnosed for a period, resulting in the production of a large number of defective cans and increasing the risk of tearing.

[0010] Diagnostic methods and devices for can bodies are known. For example, WO2018 / 020207 describes a stripper assembly for a can-making machine that includes a radial offset monitor for detecting radial misalignment of the ram and / or punch of the can-making machine, or for detecting can bodies fixed to the punch. "Short Can Sensor" products are commercially available from Sencon (UK) LTD. Summary of the Invention

[0011] According to a first aspect of the invention, a method is provided for detecting defects or deterioration of the sidewall of a can during can production in a can-making machine. Each can is formed by pushing a cup-shaped object mounted on a punch of a reciprocating ram through one or more molds housed within a can-making machine toolkit. The method includes: obtaining output signals from one or more eddy current sensors located outside the toolkit, arranged around the ram axis, and adjacent to the toolkit's outlet end; processing the output signals to detect the passage of an open end of the can sidewall through the one or more sensors, thereby determining a measurement of the height or thickness of the can sidewall; and analyzing the determined measurement to identify defects or deterioration of the can sidewall.

[0012] One or more sensors may include multiple sensors spaced angularly apart around the axis of the slide block. The determined measurements may include measurements of the height or thickness of the tank sidewall at more than one location around the circumference of the tank.

[0013] An eddy current sensor, or each eddy current sensor, can be installed within a peeler housing, which includes a peeler provided with peeling fingers.

[0014] The method may include determining whether each measurement is within a predetermined range. The measurement may be a measurement of the tank sidewall height, with the predetermined range having a width less than 10 mm, less than 5 mm, or less than 2 mm.

[0015] The method may include associating one or more signals with data indicating the position of the ram along its axis. The position data may be obtained from a linear encoder or a rotary encoder configured to rotate by a shaft used to drive the ram.

[0016] This method may include generating operator alarms or notifications when defects or deterioration of the tank sidewalls are identified.

[0017] According to a second aspect of the invention, a method for operating a can-making machine is provided. The method includes using the method described in the first aspect of the invention to detect defects or deterioration of the can sidewalls during production, and, upon detection, adjusting one or more operating parameters of the can-making machine or one or more operating parameters of the production line in which the can-making machine is located to mitigate the occurrence of the defects or said deterioration.

[0018] One or more operating parameters may include production rate.

[0019] The operating parameters can be parameters of upstream or downstream components of the can-making machine production line, such as cup-shaped presses.

[0020] According to a third aspect of the present invention, a computer device is provided, the computer device including a processor configured to perform the methods of the first and / or second aspects of the present invention described above.

[0021] According to a fourth aspect of the present invention, a computer program product is provided, the computer program product comprising instructions that, when executed by a computer, cause the computer to perform the methods of the first and / or second aspects of the present invention described above.

[0022] According to a fifth aspect of the invention, an apparatus is provided for detecting defects or deterioration of the sidewall of a can during can production within a can-making machine. Each can is formed by pushing a cup-shaped object mounted on a punch of a reciprocating ram through one or more molds housed within a can-making machine toolkit. The apparatus includes a housing disposed adjacent to the toolkit, within which one or more eddy current sensors are mounted. The housing and sensors are configured to be attached within the can-making machine such that the sensors, or each sensor, are arranged about the ram axis and adjacent to the outlet end of the toolkit. The apparatus further includes a computer processing unit that communicates with the sensors, or each sensor, via wired or wireless communication to receive output signals from the one or more sensors and is configured to process the output signals to detect the passage of an open end of the can sidewall through the one or more sensors, thereby determining a measurement of the height or thickness of the can sidewall, and analyzing the determined measurement to identify defects or deterioration of the can sidewall.

[0023] According to a sixth aspect of the invention, a system is provided comprising a can-making machine combined with the apparatus of the fifth aspect of the invention. The can-making machine includes a punch mounted on a reciprocating ram and one or more molds housed within a tool kit, with housings and sensors attached within the can-making machine such that the sensors, or each sensor, are arranged about the ram axis and adjacent to the outlet end of the tool kit.

[0024] According to a seventh aspect of the invention, a method is provided for operating a can-making machine to reduce the occurrence of can sidewall defects or deterioration during can production within the can-making machine. Each can is formed by pushing a cup-shaped object mounted on a punch of a reciprocating ram through one or more molds housed within a can-making machine toolkit. The method includes obtaining output signals from one or more eddy current sensors located outside the toolkit and arranged around the ram axis and adjacent to the toolkit's outlet end, and processing the output signals to detect the passage of an open end of the can sidewall through one or more sensors, thereby determining a measurement of the height or thickness of the can sidewall. The method further includes analyzing the determined measurements to identify can sidewall defects or deterioration, and adjusting one or more operating parameters of the can-making machine, or adjusting one or more operating parameters of other components of the production line in which the can-making machine is located, to mitigate the occurrence of defects or said deterioration.

[0025] One or more operation parameters can be selected from:

[0026] The rate of can production (the set speed of the can-making machine);

[0027] Operating temperature of the tool kit;

[0028] The rate or temperature at which coolant is supplied to the tool kit;

[0029] The rate at which lubricant is supplied to the tool kit; and

[0030] The position of the dome component relative to the axis of the slide block.

[0031] According to an eighth aspect of the invention, a system for producing cans from cup-shaped objects is provided. The system includes a can-making machine that forms cans by pushing cup-shaped objects mounted on punches of a reciprocating ram through one or more molds housed within a can-making machine toolkit. The system also includes a housing disposed adjacent to the toolkit and housing one or more sensors. The housing and sensors are attached within the can-making machine such that the sensors, or each sensor, are arranged about a ram axis and adjacent to an outlet end of the toolkit. The system further includes a computer processing unit that communicates with the sensors, or each sensor, via wired or wireless communication to receive output signals from the one or more sensors and is configured to process the output signals to detect the passage of an open end of the can sidewall through the one or more sensors, thereby determining a measurement of the height or thickness of the can sidewall. The computer processing unit is also configured to analyze the determined measurements to identify defects or deterioration in the can sidewall and adjust one or more operating parameters of the can-making machine, or one or more operating parameters of other components of the production line in which the can-making machine is located, to mitigate the occurrence of the defects or said deterioration.

[0032] One or more operation parameters can be selected from:

[0033] The rate of can production (the set speed of the can-making machine);

[0034] Operating temperature of the tool kit;

[0035] The rate or temperature at which coolant is supplied to the kit;

[0036] The rate at which lubricant is supplied to the tool kit; and

[0037] The position of the dome component relative to the axis of the slide block. Attached Figure Description

[0038] Figure 1 A schematic perspective view of a can-making machine; and

[0039] Figure 2This is a schematic cross-sectional view of a portion of a can-making machine, showing a can moving at the end of a slide between two sensors.

[0040] Figure 3 To explain from Figure 2 A graph showing the change of the output signal of one or more sensors over time;

[0041] Figure 4 A graph illustrating the measurement results derived from the output signal generated by the sensor array.

[0042] Figure 5 A schematic perspective view of multiple sensors integrated into the stripper housing; and

[0043] Figure 6 for Figure 5 A schematic cross-sectional perspective view of the peeler housing, wherein the peeler is mounted on the housing. Detailed Implementation

[0044] Figure 1 This is a perspective view of a modular can-making machine 101 for manufacturing cans from cups drawn from sheet metal. The can-making machine 101 includes a base 102 supporting a machine tool 103 with a ram assembly 105. The ram assembly 105 includes a reciprocating ram 106 with a punch (not shown) mounted at one end. During the forward stroke of the can-making machine 101, the punch contacts a cup (not shown) on the ram path within a toolkit 107. The punch pushes the cup through a redrawing die (not shown) housed within the toolkit 107 to form an elongated can. The can is carried on the punch to contact a bottom forming tool 108 housed by a dome module 109, thereby forming a dome-like shape at the bottom of the can. During the return stroke of the can-making machine 101, the can is removed from the punch by a stripper (not shown) in the toolkit 107. The tank is moved away from the slide axis by the tank unloading turntable 110 of the feed-unload module 111 located between the tool kit 107 and the dome module 109.

[0045] Tool kit 107 also includes a redrawing sleeve module 112, located in front of the redrawing die (not shown), for positioning the cup during the redrawing process. The redrawing sleeve module 112 includes a bearing 113 with a cup positioner (not shown) for receiving the cup from the feed mechanism 114 of the feed-unload module 111. The bearing 113 supports a reciprocating redrawing sleeve 115, which is coaxially aligned with the ram and has a central bore allowing the punch to pass through. The rear end of the redrawing sleeve 115 is connected to a redrawing carriage 116, which is driven in a reciprocating motion by a pair of push rods 117a, 117b located on opposite sides of the ram 106. Before the punch contacts the can, the redrawing sleeve 115 enters the open end of the cup, forcing the cup into contact with the redrawing die. As the punch pushes the cup through the orifice of the redrawing die, which is smaller in diameter than the cup, the redrawing sleeve 115 firmly holds the cup against the redrawing die in the correct position. As the cup is drawn by the punch through the redrawing die, its diameter decreases and its sidewalls lengthen. Tool kit 107 may also contain one or more thinning calendering dies or other tools for forming the can after the redrawing die. The punch then carries the elongated cup away from the redrawing sleeve module and through the remaining thinning calendering dies and tools.

[0046] Figure 2 The diagram shows some internal components of a partial can-making machine 101, including a sensor array 3 located after the thinning calendering die 4 and comprising eight sensors 2 (only two sensors 2A and 2B are visible in the figure). These eight sensors 2 are equidistantly distributed on the circumference of a circle centered on axis A-A', and the slide 106 reciprocates along axis A-A'. The figure shows the instantaneous positions of the punch 10 and the slide 106 during the forward stroke of the slide 106 after the can 8 mounted on the punch 8 passes through the thinning calendering die 4.

[0047] Sensor 2 is an eddy current sensor, such as those made of Micro-Epsilon. TM Manufactured eddyNCDT TMThis series of sensors can be used to measure the distance to conductive objects with very high accuracy, for example, less than 1 micrometer. Advantageously, no contact with the object is required, making the measurement wear-free. Each eddy current sensor 2 includes a coil (not shown) located within a housing. The coil is supplied with high-frequency alternating current to generate an electromagnetic field. The electromagnetic field of the coil induces eddy currents in a conductive material (such as the material of the can 10), which generates an opposing magnetic field that cancels out the magnetic field generated by the coil according to Lenz's law. The sensor 2 is configured to generate a voltage output that depends on the strength of the opposing magnetic field, which is determined by the distance between the conductive material and the coil. The sensor 2 has an effective area or "spot size" within which the conductive material needs to be located to generate a detectable output signal. For example, when the sensor is used to detect conductive material at a distance of approximately 3 millimeters, the effective area can be approximately 1 cm. 2 Although shielding can be used to reduce the size of the area if necessary. Figure 2 The diagram shows the effective areas 12A and 12B of two sensors 2A and 2B. Sensors 2 are oriented toward axis A-A', such that the tank passes through their respective effective areas when carried by the punch 8 along axis A-A'.

[0048] Eddy current sensors are superior to other types of sensors, such as inductive proximity sensors, which are typically limited by the frequency response of the ferromagnetic core used in these sensors and thus have a lower time resolution, for example, less than about 50 Hz (i.e., measurements per second).

[0049] As mentioned above, eddy current sensors have previously been used to monitor the radial alignment (or offset) of the punch / slide. To do this, the output signal from the sensor is typically processed to generate an angular deflection trajectory of the punch / slide over time, whether in a single stroke or multiple strokes. Since the signal is dominated by the sensor that detects the punch / slide, this trajectory can provide useful diagnostic information about the radial alignment of these components relative to the sensor. For example, radial misalignment of the slide relative to the dome can be identified by the relatively large vibratory motion generated in the slide due to the punch striking the dome off-center. However, surprisingly, the eddy current output signal can also be used to obtain useful diagnostic information about the height of the tank sidewalls (as described below). This is possible, although the signal generated from the thin tank sidewalls is smaller in amplitude and shorter in duration than the signal generated from the punch / slide. Eddy current sensors are particularly advantageous for these types of measurements because they can operate at much higher frequencies (e.g., MHz) than other types of inductive sensors, which allows for a time resolution high enough to accurately distinguish the movement of the tank past the sensor. Another advantage of using eddy current sensors is that they do not need to be calibrated to account for changes in the punch composition.

[0050] Figure 3 An exemplary output signal 300 (shown on the vertical axis) obtained from one of the sensors as a function of time (shown on the horizontal axis) is shown. Signal 300 includes (in ascending order of time): a low value (e.g., zero) initial portion 302, corresponding to the time before the bottom of the can enters the effective area of ​​the sensor; a rising edge 304, caused by an increase in the proportion of the can filling the effective area; a) a steady portion 306, in which the signal is approximately constant, with a value of s1, corresponding to the can fully filling the effective area of ​​the sensor; b) a falling edge 308, related to a decrease in the proportion of the can and the punch leaving the effective area; and b) a later steady region 310, in which the signal is approximately constant, with a value of s2, corresponding to the case where the sensor only detects the punch.

[0051] The output signal 300 generated by the sensors is processed to determine the entry time t0 related to the given angular position of the tank entering the effective area and the subsequent exit time t1 related to the angular position of the tank exiting the effective area 12. Figure 3 In the example shown, the entry time t0 is determined from the rising edge 304 of the output signal 300 by identifying a value associated with the stationary portion 306 of the signal (e.g., by fitting a line through the data points of the signal 300), and then determining the time when the signal reaches half (or some other fraction) of the value s1 within the rising edge portion 304, for example, by fitting an interpolation function (such as a polynomial or spline function) to the rising edge 304 and using a root-finding algorithm (such as Newton's method) to determine the entry time t0. A similar procedure can be used to determine the exit time t1 from the falling edge portion 308 of the signal 300 using values ​​s1, s2 associated with adjacent stationary regions 306, 310. Other methods can also be used to locate the rising and / or falling edges of the signal 300. The entry and exit times t0, t1 can also be corrected using a heuristic function obtained by calibrating the entry and exit times of tanks at different known heights.

[0052] The contribution of the punch and / or ram to signal 300 can be eliminated by recording a "background" signal (when the can-making machine is operating without a can on the punch) and then subtracting the background signal from signal 300 obtained during normal operation of the can-making machine. In some cases, the background signal may be the average of more than one signal obtained when there is no can on the punch (e.g., the mean).

[0053] Figure 4This is a graph showing the exit time 400 (vertical axis of the graph) obtained by processing signals 300 from each of the eight sensors in the sensor array, and then plotted based on the variation of the angle of each sensor around the axis A-A' of the slide (horizontal axis of the graph). The variation of the exit time 400 relative to the angle comes from the tank sidewall (in... Figure 2 The height variation around its axis (indicated by reference numerals 14A and 14B in the attached diagram). For example, the exit time 400A determined from the signal 300 of sensor 2A precedes the exit time 400B determined from the signal 300 of sensor 2B because the side wall height 14A of the tank is less than the side wall height 14B on the opposite side of the tank diameter.

[0054] The exit time 400 of each can in a series cans can be compared to each other to assess the quality of the sidewalls of the series cans (either by preserving angular information or by looking at the average sidewall height of each can). For example, measurements of the dispersion of exit times 400 can be calculated, such as the difference between the maximum and minimum exit times 400, or the standard deviation / variance of exit times 400. This measurement can be converted into a distance measurement by multiplying it by the speed of the ram. If the measurement (or distance measurement) falls outside a predetermined range, the produced cans can be deemed to have a specific quality grade; for example, a distance measurement less than or equal to 50 micrometers can be considered acceptable, while a distance measurement greater than 50 micrometers is considered to indicate poor edge uniformity of the can, such as the presence of a "sugar scoop" defect.

[0055] Additionally, exit times 400 can be monitored to ensure that none of them fall outside a predetermined range. For example, outliers or trends in exit times 400 obtained for different (e.g., consecutive) cans can be monitored, which may indicate wear or damage to the can-making machine's tools (e.g., thinning calendering dies) or a lack of uniformity in the cups supplied to the can-making machine, which may be caused by variations in the metal coils used to manufacture the cups.

[0056] Signal 300 and / or exit time 400 can be correlated with longitudinal position data of the ram (and therefore the punch) during each stroke. This data can be obtained, for example, from a high-resolution rotary encoder or a high-resolution linear encoder, which rotates via a shaft used to drive the reciprocating ram, and the linear encoder directly measures the longitudinal position of the ram. This correlation makes it easier to identify features in the signal data corresponding to the tank, rather than other features generated by noise or parts of the punch / ram that might be detected by the sensor. For example, position data can be used to process signal 300 as a function of ram position rather than time; therefore, only the portion of signal 300 corresponding to the punch end near or within the effective area of ​​the sensor needs to be analyzed. Furthermore, the processing described above for signal 300 that varies with time can be similar to the processing of signal 300 that varies with ram position, allowing direct evaluation of the height of each tank sidewall to be evaluated without needing to evaluate the ram speed (which may vary with the stroke).

[0057] While multiple sensors around the ram axis allow for the determination of changes in tank sidewall height, useful data can still be obtained using only a single sensor. For example, data from a single sensor can be used to monitor trends and / or outliers between strokes, which may indicate deteriorating alignment, wear, and / or variations in feed metal.

[0058] The processing of signals 300 obtained from the sensor array is performed by a computer device (not shown) that digitizes the signals 300 using an analog-to-digital converter (ADC). These signals are provided to the computer device via a wired or wireless connection. The computer device includes a memory storing instructions for processing the signals 300 according to the described method and a processor for executing those instructions. The instructions may be provided to the computer device from computer-readable non-transient storage media or other computer program products (e.g., computer programs downloaded from the Internet). The sensor data 300 and / or the time obtained by processing the data may be recorded by the computer device, for example, in a database, for later retrieval and analysis or for generating “quality control” reports for a specific stage of can production or can batch. The computer device may also be used to control the can-making machine based on the exit time 400 obtained from processing the sensor signals 300, for example, stopping can production if the exit time 400 does not meet one or more criteria, or adjusting one or more operating parameters of the can-making machine (such as setting speed / repetition rate) based on the exit time 400.

[0059] Measurements 300 obtained from sensor array 500 during can production can be analyzed using machine learning, analytics, and / or artificial intelligence techniques to determine how to improve the operation of the can-making machine. For example, evolutionary algorithms (or other types of optimization algorithms) can be used to change the operating parameters of the can-making machine (e.g., based on the fitness level based on exit time 400) to determine the percentage of sidewall height in the produced cans that falls within a predetermined range.

[0060] The operating parameters provided to the algorithm and / or control of the can-making machine may include one or more of the following: the can production rate (the set speed of the can-making machine), the operating temperature of the tool kit, the rate of supplying coolant to the tool kit, the rate of supplying lubricant to the tool kit, the rate of supplying blanks to the can-making machine, and the position (alignment) of the dome relative to the ram axis. The algorithm may also take other types of data as input, such as the time elapsed since the can-making machine was last serviced or reconfigured, the number of cans produced using the current set of molds, and / or measurements of raw material quality, such as the thickness or weight of the cups supplied to the can-making machine.

[0061] In some cases, optimization algorithms can be used to optimize (e.g., maximize) specific parameters, constrained by the tank sidewall height determined from the data 300 of the sensor array 500. For example, if the sidewall height remains within an acceptable range (and other operating parameters also remain within acceptable / safe ranges), tank productivity can be optimized.

[0062] Feedback control can also be used to adjust one or more can-making machine operating parameters to compensate for changes in the can-making machine over time due to wear or movement of can-making machine components. For example, a proportional-integral-derivative (PID) controller can be used to change the can-making machine operating parameters to minimize the error signal determined by the variation of the outlet time 400 with the can-making machine's operating parameters.

[0063] Feedback control can be extended to other upstream and downstream components of a can production line, including the can-making machine. For example, feedback can be used to control components such as the upstream cup press. When several sources of billet are located upstream of the can-making machine, the detection of a defect can be traced back to a specific cup press, and that cup press can be controlled accordingly, such as by shutting it down. Defects can also be traced back to a specific supply of metal coils.

[0064] Tracing the sources of defects identified using the system described above can be aided by markings or other readable data on the blanks supplied to the can-making machine. For example, laser-etched markings can be read inside the can-making machine or at its output and correlated with can quality data.

[0065] Clustering or other types of classification algorithms can also be used to identify quality variations in cans being produced, for example, as a result of damage to one or more kit components (such as a mold) or misalignment of the slide.

[0066] Figure 5 An exemplary sensor array 500 is shown, comprising a plurality of sensors 500A-D housed within the outer circumference of a peeler housing 502, which is generally annular. In this example, four sensors 500A-D are equidistantly distributed around the peeler housing 502, although fewer, or additional, sensors may be used (as described above). The housing 502 includes an inner bore configured to receive a canister of a specific diameter located on the punch. The peeler housing 502 is mounted to a tool kit 107 following a tool kit bracket (not shown). The placement of the sensors 500A-D within the peeler housing 502 keeps the tools (i.e., tool kit components) stationary and provides a degree of protection for the sensors when changing tools.

[0067] Figure 6 This is a three-dimensional cross-sectional view of the adapter plate 600, which is attached to the tool kit 107 (not shown), and the peeler housing 502 is mounted on the adapter plate 600. A steel peeler 604 is held in place on the peeler housing 502 by a retaining ring 604 and a peeler adapter ring 606. Although a steel peeler 8b is shown in this example, a plastic peeler or other peelers may also be used. An air gap is provided around each sensor face 608 so that the sensor face 608 does not contact the peeler housing 502.

[0068] The stripper housing 502 is configured to accommodate four adjustment mechanisms, one near each of the eddy current sensors 500A-D. In this example, each adjustment mechanism includes a miniature high-precision ball screw 610 and a guide mechanism 612. The ball screw 610 converts rotary motion into linear motion. Each screw 610 includes a movable collar 614 attached to the guide mechanism 612, which in turn is attached to the adjacent eddy current sensor 500A-D.

[0069] When the ball screw 610 is adjusted manually or automatically, the collar 614, guide mechanism 612, and eddy current sensor 500A can be adjusted in a direction orthogonal to the inner surface of the stripper housing 502. In other words, the eddy current sensor 500A can be adjusted, screwed in or out, so that the surface of the sensor 608 protrudes from, is flush with, or recessed into the inner surface of the stripper housing 502. Understandably, the position of the sensor surface 500A can be adjusted according to the diameter of the slide 106 to be used, or to optimize the signal 300 obtained from the sensor 500A-D to minimize the "background" signal generated by the punch rather than the can.

[0070] In principle, other sensors besides eddy current sensors (or similar sensors) can also be used to obtain suitable output signals. For example, optical sensors (e.g., photodiodes) can be used to image a tank or measure changes in reflectivity caused by the tank passing in front of the optical sensor. Optical sensors should be cleaned regularly (e.g., by continuously passing a cleaning fluid) to prevent the accumulation of oil, dust, and dirt. Therefore, non-optical sensors (such as eddy current sensors) are preferred.

[0071] Those skilled in the art will understand that various modifications can be made to the above embodiments without departing from the scope of the present invention.

Claims

1. A method for detecting defects or deterioration of the sidewalls of cans during can production in a can-making machine, each can being formed by pushing a cup-shaped object mounted on a punch of a reciprocating ram through one or more molds housed within a can-making machine toolkit, the method comprising: The output signal is obtained from one or more eddy current sensors located outside the tool kit, arranged around the axis of the slide, and adjacent to the exit end of the tool kit; The output signal is processed to detect the passage of one or more sensors through the open end of the tank sidewall, thereby determining the measured value of the tank sidewall height; as well as The determined measurements are analyzed to identify defects or deterioration in the tank sidewalls.

2. The method according to claim 1, wherein, The one or more sensors include a plurality of sensors spaced angularly apart around the axis of the slide block, and the determined measurements include measurements of the height of the tank sidewall at more than one location around the circumference of the tank.

3. The method according to claim 1, wherein, The eddy current sensor, or each eddy current sensor, is installed inside the peeler housing, which includes a peeler provided with peeling fingers.

4. The method of claim 1, further comprising determining whether each measurement is within a predetermined range.

5. The method according to claim 4, wherein, The measured value is the height of the tank sidewall, and the predetermined range has a width of less than 10 mm, less than 5 mm, or less than 2 mm.

6. The method of claim 1, further comprising associating one or more signals with data indicating the position of the slide along the slide axis.

7. The method according to claim 6, wherein, Position data is obtained from a linear encoder or a rotary encoder configured to rotate by a shaft used to drive the slide.

8. The method of claim 1, further comprising generating an operator alarm or notification upon identification of defects or deterioration in the tank sidewall.

9. A method of operating a can-making machine, comprising using the method of claim 1 to detect defects or deterioration of the can sidewall during production, and, upon detection of such defects, adjusting one or more operating parameters of the can-making machine or one or more operating parameters of the production line in which the can-making machine is located to mitigate the occurrence of the defects or said deterioration.

10. The method according to claim 9, wherein, The one or more operating parameters include production rate.

11. The method according to claim 9, wherein, Operating parameters are the parameters of upstream or downstream components in the can-making machine production line.

12. The method according to claim 11, wherein, The upstream component of the can-making machine production line is the cup-shaped press.

13. A computer device comprising a processor configured to perform the method of claim 1.

14. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the method of claim 1.

15. A device for detecting defects or deterioration of the sidewalls of cans during can production in a can-making machine, each can being formed by pushing a cup-shaped object mounted on a punch of a reciprocating ram through one or more molds housed within a can-making machine tool kit, said device comprising: A housing disposed adjacent to the tool kit, wherein one or more eddy current sensors are installed, and the housing and sensors are configured to be attached to the can-making machine such that the sensors, or each sensor, are arranged about the ram axis and adjacent to the outlet end of the tool kit; and A computer processing unit, which communicates with the sensors or each sensor via wired or wireless communication, to receive output signals from one or more sensors and is configured to process the output signals to detect the passage of the open end of the tank sidewall through one or more sensors, thereby determining a measured value of the height of the tank sidewall, and analyzing the determined measured value to identify defects or deterioration of the tank sidewall.

16. A system comprising a can-making machine in conjunction with the apparatus of claim 15, the can-making machine comprising a punch mounted on a reciprocating ram and one or more molds housed within a tool kit, a housing and sensors attached within the can-making machine such that the sensors, or each sensor, are arranged about the ram axis and adjacent to the outlet end of the tool kit.

17. A method of operating a can-making machine to reduce the occurrence of can sidewall defects or deterioration during can production within the can-making machine, each can being formed by pushing a cup-shaped object mounted on a punch of a reciprocating ram through one or more molds housed within a can-making machine toolkit, the method comprising: Output signals are obtained from one or more sensors located outside the toolbox, arranged around the axis of the slide, and adjacent to the exit end of the toolbox; The output signal is processed to detect the passage of one or more sensors through the open end of the tank sidewall, thereby determining the measured value of the tank sidewall height; Analyze the determined measurements to identify defects or deterioration in the tank sidewalls; as well as Adjust one or more operating parameters of the can-making machine, or adjust one or more operating parameters of other components on the production line in which the can-making machine is located, to mitigate the occurrence of defects or said deterioration.

18. The method according to claim 17, wherein, The one or more operating parameters are selected from: The rate of can production; Operating temperature of the tool kit; The rate or temperature at which coolant is supplied to the kit; The rate at which lubricant is supplied to the tool kit; as well as The position of the dome component relative to the axis of the slide block.

19. A system for producing cans from cup-shaped objects, the system comprising: A can-making machine that forms a can by pushing a cup-shaped object mounted on a reciprocating ram through one or more molds contained in a can-making machine tool kit; A housing disposed adjacent to the tool kit, wherein one or more sensors are installed, the housing and sensors are attached to the can-making machine such that the sensors, or each sensor, are arranged around the ram axis and adjacent to the outlet end of the tool kit; and A computer processing unit, which communicates with the sensors or each sensor via wired or wireless communication, receives output signals from one or more sensors and is configured to process the output signals to detect the passage of the open end of the tank sidewall through one or more sensors, thereby determining a measured value of the height of the tank sidewall, analyzing the determined measured value to identify defects or deterioration of the tank sidewall, and adjusting one or more operating parameters of the can-making machine or one or more operating parameters of other components in the production line where the can-making machine is located to mitigate the occurrence of defects or said deterioration.

20. The system according to claim 19, wherein, The one or more operating parameters are selected from: The rate of can production; Operating temperature of the tool kit; The rate or temperature at which coolant is supplied to the kit; The rate at which lubricant is supplied to the tool kit; as well as The position of the dome component relative to the axis of the slide block.

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