Monitoring of can body manufacturers

Abstract

A can bodymaker for producing can bodies from cups. The can bodymaker includes a ram configured to reciprocate along an axis, a punch mounted on the ram, a cradle, and a tool pack including a plurality of tools positioned within the cradle for squeezing and squeezing a cup mounted on the punch during a forward stroke of the ram. The can bodymaker further includes a bolster plate secured to the can bodymaker, an adapter plate secured to the bolster plate, a stripper assembly secured to the adapter plate for removing the can body from the punch during a return stroke of the ram, and a clamping mechanism for biasing the tools against a front face of the adapter plate. The can bodymaker further includes one or more load cells disposed in or on the adapter plate and configured to generate one or more output signals indicative of an axial force acting on the tool by the cup passing therethrough.

Description

[Technical Field]

[0001] The present invention relates to monitoring can body makers. In particular, the present invention relates to an apparatus and method for monitoring the forces acting on components in a tool pack of a can body maker as the can body maker is driven. [Background technology]

[0002] In a known can bodymaker for producing two-piece thin-walled metal can bodies by the "draw and iron" (DWI) process, a metal cup is fed into the bodymaker, then carried by a punch at the end of a tamping rod and passed through a series of dies to produce a can body of the desired size and thickness. The series of dies may include a redraw die for reducing the cup's diameter and extending its sidewall, and one or more ironing dies for ironing the cup into a can body. The area or cradle of the bodymaker frame in which the dies are placed is known as the "tool pack." The can body carried on the punch may eventually come into contact with a bottom forming tool or "domer" to form a dome or other shape at the base of the can. An exemplary bodymaker is described in U.S. Patent No. 5,629,999.

[0003] Can body makers are typically operated at high production rates of greater than about 300 to 400 can bodies per minute for extended periods of time. However, the quality of the can bodies produced can vary significantly over time due to, for example, changes in the alignment of machine components, coolant temperature and flow rate, machine lubrication, and / or the quality of the incoming cup (e.g., due to variations in the quality of the metal coil from which the cup is made).

[0004] During the DWI process, the punch experiences loads as it forces the metal through the ironing die. However, the magnitude and distribution of these loads vary both during and between strokes, leading to variations in the quality of the can bodies produced. For example, frictional forces and general wear can cause slight changes in the alignment of the ram over time. In addition, the rapidly reciprocating ram typically experiences at least some vibration due to the ram's impact with the can body and its variable "gravity bow" as it moves to and from its fully extended position.

[0005] As a further example, when the poker carries the can body into contact with the domer, any misalignment can lead to cracking of the end of the can body, especially when the can body is made from aluminum. If the misalignment is slight, the crack (often known as a "smile") may not be immediately visible to the naked eye and may lead to the can bursting after the can body has been filled. This may also occur after the filled can has been purchased.

[0006] Poor quality can bodies can lead to waste and downtime in the can maker. This can result, for example, from having to realign or repair the body maker itself, or from other machinery further down the production line being adversely affected by the poor quality cans being produced. Unfortunately, the high-speed, high-volume nature of the can making industry means that lost production time can be very costly to manufacturers.

[0007] Traditionally, aligning and realigning bodymakers has been a complex and time-consuming process that requires labor by skilled operators (who are often in short supply) and is undertaken only after serious problems have developed. When setting up a can bodymaker, the ram and its drive components are typically secured in place on the bodymaker's frame. This aligns the ram's axis with the bodymaker's main axis. Other components, including, for example, redraw and ironing molds and domers, are then aligned with the ram. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 9934942 Summary of the Invention [Means for solving the problem]

[0009] According to a first aspect of the present invention, there is provided a can bodymaker for producing can bodies from cups. The can bodymaker includes: a ram configured to reciprocate along an axis; a punch mounted on the ram; and a tool pack including a cradle and a plurality of tools located within the cradle for squeezing and squeezing a cup mounted on the punch during the forward stroke of the ram. The can bodymaker further includes: a bolster plate secured to the can bodymaker; an adapter plate secured to the bolster plate; a stripper assembly secured to the adapter plate for removing the can body from the punch during the return stroke of the ram; and a clamping mechanism for biasing the tools against a front face of the adapter plate. The can bodymaker further includes one or more load cells located in or on the adapter plate and configured to generate one or more output signals indicative of the axial force acting on the tools due to the cup passing therethrough.

[0010] The term "axial force" means a force having a component directed along the axis along which the tamping rod reciprocates.

[0011] The can body maker can include an encoder configured to provide a measurement of the position of the tamper one or more times during each reciprocation. The encoder can be a linear encoder. Alternatively, the encoder can be a rotary encoder configured to be rotated by a shaft used to drive the tamper.

[0012] The one or more load cells may be piezoelectric load cells.

[0013] The one or more load cells can include two or more load cells, the load cells being equally angularly spaced from one another about the axis.

[0014] The can bodymaker can include a processor configured to adjust one or more operating parameters of the bodymaker, such as the speed of reciprocating movement of the poker, in response to the output signal.

[0015] The adapter plate can be secured to the bolster plate by one or more pressure bolts, each of which passes through a corresponding one of the load cells and secures the load cell between the adapter plate and the bolster plate.

[0016] The stripper assembly may include a radial offset monitor for detecting axial misalignment of the ram and / or punch.

[0017] The radial offset monitor can include a bore configured to allow passage of the punch and tamping rod, and one or more spaced eddy current sensors around the bore.

[0018] According to a second aspect of the present invention, there is provided an apparatus for improving a can bodymaker comprising: a ram configured to reciprocate along an axis; a punch mounted on the ram; a tool pack including a cradle and a plurality of tools located within the cradle for squeezing and squeezing a cup mounted on the punch during the forward stroke of the ram; a bolster plate secured to the can bodymaker; an adapter plate secured to the bolster plate; a stripper assembly for removing the can body from the punch during the return stroke of the ram; and a clamping mechanism for biasing the tools against the front face of the adapter plate. The apparatus also includes: a replacement adapter plate for securing to the bolster plate in place of the adapter plate of the can bodymaker; and one or more load cells located in or on the replacement adapter plate and configurable to generate one or more output signals indicative of the axial force acting on the tools due to the cup passing therethrough.

[0019] The replacement adapter plate can include a stripper assembly including a radial offset monitor for detecting axial misalignment of the tamping rod and / or punch. The radial offset monitor can include a bore configured to allow passage of the punch and tamping rod and one or more spaced eddy current sensors about the bore.

[0020] According to a third aspect of the present invention, there is provided a method of calibrating the apparatus of the second aspect after it has been retrofitted to a can bodymaker. The method includes mounting a calibration fixture in a cradle of the can bodymaker, the calibration fixture including one or more reference load cells configured to generate one or more output signals indicative of an axial force acting on a tool located in the cradle. The axial force is applied to the tool and the one or more reference load cells using a clamping mechanism of the can bodymaker. The one or more output signals of each of the reference load cells are used to determine a calibration coefficient or function for estimating the force on the tool from the output signals generated by the load cells of the apparatus.

[0021] According to a fourth aspect of the present invention, a method of operating a can bodymaker is provided that mitigates the effects of tool wear, damage, and / or misalignment during the production of can bodies. Each can body is formed by forcing a cup attached to a punch on an axially reciprocating tread through a tool housed in a cradle in a tool pack of the can bodymaker. The method includes obtaining output signals from one or more load cells, i.e., load cells located in or on an adapter plate attached to a bolster plate secured to the can bodymaker, indicative of the axial force acting on the tool due to the cup passing through it. The output signals are processed to obtain data indicative of one or more of the tools being worn, damaged, and / or misaligned with respect to the tread. One or more operating parameters of the can bodymaker or another component of the production line in which the bodymaker is located are adjusted based on the data to mitigate the effects of one or more tools being worn, damaged, and / or misaligned with respect to the tread.

[0022] One or more of the operating parameters are: can making rates and; Tool pack operating temperature and; Coolant supply rate or temperature to the tool pack; The supply rate of lubricant to the tool pack; the position of the domer in relation to the axis of the ram; It may include one or more of:

[0023] The one or more operating parameters can include parameters of a manufacturing line component upstream or downstream of the body maker, such as a cup press.

[0024] The method may include removing the can body from the punch during a return stroke of the punch using a stripper secured to the adapter plate.

[0025] The stripper can be provided in a stripper assembly that includes a radial offset monitor, and the method further includes obtaining an output signal indicative of a position of the ram and / or punch perpendicular to the axis using the radial offset monitor, and adjusting one or more operating parameters based on the data and the output signal obtained from the radial offset monitor. [Brief explanation of the drawings]

[0026] [Figure 1] FIG. 2 is a schematic perspective view illustrating a can body maker. [Figure 2] FIG. 2 is a schematic cross-sectional perspective view of the can body maker tool pack of FIG. 1; [Figure 3] FIG. 2 is another schematic cross-sectional perspective view of the can body maker of FIG. 1. [Figure 4] FIG. 10 is a schematic rear perspective view of the adapter plate and stripper assembly. [Figure 5] FIG. 5 is a schematic cross-sectional side view of the adapter plate and stripper assembly of FIG. 4. [Figure 6] FIG. 5 is a schematic front perspective view of the adapter plate and stripper assembly of FIG. 4. [Figure 7]FIG. 1 is a schematic cross-sectional side view of a load cell mounted between the adapter plate and bolster plate of a tool pack. [Figure 8] 1 is a flow chart illustrating a method of operating a can bodymaker that reduces the effects of tool wear, damage, and / or misalignment during the production of can bodies. DETAILED DESCRIPTION OF THE INVENTION

[0027] FIG. 1 is a schematic perspective view of a modular bodymaker 101 for creating can bodies from cups drawn from sheet metal. The bodymaker 101 includes a machine bed 103 with a work surface and a base 102 supporting a ram assembly 105. The ram assembly 105 includes a reciprocating ram 106 with a punch (not shown) attached to one end. During the forward stroke of the bodymaker 101, the punch contacts a cup (not shown) held in a ram passage in a tool pack 107 located on the work surface. The punch forces the cup through a redraw mold (not shown) housed in the tool pack 107 to form an elongated can body. The can body contacts a bottom-forming tool 108 carried on the punch and housed by a domer module 109, resulting in the formation of a dome or other shape at the base of the can. On the return stroke of the bodymaker 101, the can body is removed from the punch by a stripper (not shown) in the tool pack 107. The can body is carried off the ram shaft by a can discharge turret 110 in an infeed-discharge module 111 located between the tool pack 107 and the domer module 109.

[0028] The tool pack 107 also includes a redraw sleeve module 112 located in front of the redraw mold (not shown) for positioning the cup during the redraw process. The redraw sleeve module 212 includes a support structure 113 with a cup locator (not shown) that receives the cup from the infeed mechanism 114 of the infeed-discharge module 111. The support structure 113 supports a reciprocating redraw sleeve 115 that is coaxially aligned with the ram and has a central bore that allows the punch to pass through. The rear end of the redraw sleeve 115 is coupled to a reciprocating redraw carriage 116 driven by a pair of push rods 117a, 117b located on either side of the ram 106. Before the punch contacts the can, the redraw sleeve 115 penetrates the open end of the cup, forcing the cup into contact with the redraw mold. The redraw sleeve 115 holds the cup in place and securely against the redraw mold as the punch pushes the cup through an opening in the redraw mold that is smaller in diameter than the cup. As the cup is drawn by the punch through the redraw mold, its diameter is reduced and its sidewalls are stretched. Tool pack 107 may also contain one or more ironing molds or other tooling for forming the can body after the redraw mold. The punch then carries the stretched cup away from the redraw sleeve module through the remaining ironing molds and tooling.

[0029] 2 and 3 are cross-sectional perspective views of the tool pack 107, which includes a housing 219 with a cradle 220 mounted therein and a stripper assembly 221. The stripper assembly 221 is attached by an adapter plate 225 to a bolster plate 223, which is attached to the housing 219 and provides the rear wall of the tool pack 107. The dashed line A-A' in FIG. 2 indicates the axis along which the punch (not shown) moves. The cradle 220 has a cylindrical inner surface and a wear bar 229 used to support the ironing die (not shown), as well as spacer rings (226A, B) inside the housing 219. The redraw die (not shown) is attached to the front of the housing 219, forming the entrance to the housing 219 into which the punch moves during the advancement stroke of the ram 106.

[0030] The stripper assembly 221 includes a stripper 233 mounted within a stripper housing 235 attached to the adapter plate 225. The stripper 233 includes stripper fingers extending radially inward, i.e., toward the axis A-A'. As a can body carried on the punch 106 moves through the stripper 233 during the forward stroke of the ram 106, it deflects the stripper fingers. On the return stroke, i.e., away from the bottom forming tool 108, the stripper fingers prevent the can body from returning with the punch, and the can body is stripped from the punch and then removed from the bodymaker 201 by the can discharge turret 210. In other embodiments not shown, the can bodies can be removed from the bodymaker 201 by compressed air (alternatively, compressed air can be used to assist the stripper in removing the can bodies).

[0031] Adapter plate 225 is located between bolster plate 223 and tool pack housing 219. Adapter plate 225 contains three load cells 237A-C (see FIGS. 4-6) equally spaced about axis A-A', each with its axis toward cradle 220 oriented along axis A-A', to measure the force generated by the punch passing through the die. In this example, load cells 237A-C are piezoelectric load cells, and each generates an electrical signal when compressed along its axis (which is preferably aligned parallel to axis A-A').

[0032] FIG. 4 shows the back of adapter plate 225 with bolster plate 223 (and the remainder of tool pack 107) removed to reveal each of the three load cells 237A-C. The ring 301B of each of load cells 237A-C sits in a recess formed in the edge and back of adapter plate 225 (i.e., the face of adapter plate 225 farthest from tool pack cradle 220). In this example, each recess is shaped to accommodate a wired connection to the side of ring 301B. Load cell 237A also includes a pressure bolt 301B that passes through adapter plate 225, through the center of ring 301B, and into bolster plate 223. Cylinder 301A protrudes from the recess so that it contacts bolster plate 223 across the small gap between adapter plate 225 and bolster plate 223 (see FIG. 7). Preload bolt 301B is used to bias adapter plate 225 toward bolster plate 223 so that annulus 301A is held in compression between adapter plate 225 and bolster plate 223. Application of a force to adapter plate 225 in the direction of bolster plate 223 results in further compression of annulus 301A (i.e., preload 301B does not prevent adapter plate 225 from moving toward bolster plate 225).

[0033] FIG. 5 shows a vertical cross section through adapter plate 225 and stripper assembly 221 along axis A-A'.

[0034] FIG. 6 shows a perspective view of the front of adapter plate 225 (i.e., the side closest to tool pack cradle 220).

[0035] 7 shows adapter plate 225 bolted to bolster plate 223 using pressure bolt 301B that passes through cylinder 301A of load cell 237A. Cylinder 301A is held in compression between the back of adapter plate 225 and the front of bolster plate 223.

[0036] In the particular embodiment shown in FIGS. 4-7, the stripper housing 235 includes four eddy current sensors 401A, B (one or more than four eddy current sensors could be used) spaced around a central bore through which the tampers travel to monitor the radial offset of the punch / tampers. The radial offset data from the eddy current sensors can be correlated with force data acquired from load cells 237A-C. This correlation helps identify the cause of radial misalignment between the tampers / punches and tool pack components. For example, an abnormally high force resulting from a punch passing through one of the molds could result from a misaligned tamper / punch or from misalignment of the mold itself; these two possibilities can be clearly distinguished from each other using the radial offset data.

[0037] 2 and 3, as the punch moves through cradle 220 (i.e., from left to right in FIG. 2), the can body is forced through the redraw and ironing dies, which creates a longitudinal force that is transmitted through the dies and spacer rings to load cells 237A-C. Thus, the time-varying signals produced by load cells 237A-C provide a measure of the longitudinal force acting on the dies as the sidewall of the can body is drawn and / or ironed.

[0038] The load cells 237A-C may be provided in an equiangular arrangement about axis A-A' to provide optimal sensitivity. A minimum of three load cells 237A-C is preferred to provide sufficient spatial detail, with the maximum number of load cells 237A-C limited only by cost and available space in adapter plate 225. Other types of load cells 237A-C, such as capacitive load cells, may also be used in place of or in addition to the piezoelectric load cells.

[0039] The adapter plate 225 can be retrofitted to existing can body makers without modifications to the tool pack, for example, by replacing the existing adapter plate.

[0040] Because the load cells 237A-C are located outside the cradle 220, force measurements can be made without requiring reconfiguration or replacement of components (tools) within the cradle 220. For example, in principle, it would be possible to attach a fixture to the load cells 237A-C instead of one of the spacer rings, but this would require the fixture to be manufactured to high tolerances, and multiple versions of the fixture may be required depending on the molds included in the tool pack. Also, such an arrangement could have a detrimental effect on the cooling provided to the molds. Including the load cells 237A-C inside the cradle 220 can also be problematic because the attachment and removal of components to and from the cradle 220 could be prone to damaging the load cells 237A-C.

[0041] While it is possible to make force measurements using a single load cell 237A, it is preferable to have two or more transducers to obtain information about how the forces acting on the mold are spatially distributed. For example, using multiple load cells 237A-C, it is possible to determine that the relative alignment between one or more of the ram / punch and mold requires correction, e.g., using an iterative procedure in which the forces measured by each of the load cells 237A-C are compared and the alignment of the ram and / or mold is changed until the forces are balanced and / or each of the measured forces is minimized. In practice, this procedure can be implemented using a computing device (not shown) that includes an analog-to-digital (ADC) converter, processes the time-varying electrical signals generated by the load cells 237A-C, and generates a graphical display or reading of the forces that can be viewed by an operator to make any necessary adjustments.

[0042] In some cases, the computing device can be configured to detect when a force exceeds a threshold and / or whether there is an imbalance in the measured forces that exceeds a threshold (e.g., whether one of the measured forces is greater than the others) and respond by generating a visual or audible alarm and / or stopping operation of the can body maker 201. The computing device can also control one or more operating parameters of the can body maker 101 to ensure that it is operating safely and efficiently. For example, the computing device can reduce the repetition rate of the can body maker 101 if a problem begins to develop.

[0043] The time-varying measurements obtained from the load cells 237A-C can be recorded (e.g., stored in a database) to allow monitoring of gradual changes in alignment caused by wear and vibration. The time resolution provided by the ADC is sufficient to resolve the temporal fluctuations in force measured over the course of a single stroke. This data can be correlated with longitudinal position data for the ram during each stroke (i.e., data indicating the movement of the ram along axis A-A'). This data can be obtained, for example, from a high-resolution rotary encoder rotated by the shaft used to drive the reciprocating motion of the ram, or from a high-resolution rotary encoder that more directly measures the longitudinal position of the ram. Correlating the force measurements with the position data allows specific features in the force measurements to be attributed to the passage of the ram through specific components of the tool pack, for example, identifying a particular mold as poorly aligned or damaged, or inferring the wear of each mold from the total force on each mold integrated over multiple strokes. This analysis can be performed automatically by a computing device that can generate a warning signal or alert indicating that one or more molds need realignment or replacement. The number of passes can also be recorded so that the measured force data can be associated with a particular can or cans produced by bodymaker 201, for example, to qualify a particular can or batch of cans as defect-free or, conversely, to prevent others from being shipped to a customer.

[0044] It is not essential that the load cells 237A-C be calibrated, as it is still possible to obtain useful information from the relative forces measured by each of the load cells 237A-C (e.g., detect changes in the relative alignment of components over time). Nevertheless, calibrating the load cells 237A-C can allow a more accurate model of the forces acting on the mold to be constructed, thereby allowing for more sophisticated processing of measurements to be performed and for potential problems to be detected earlier. As used herein, "calibration" refers to the conversion from the electrical signals produced by the load cells 237A-C and the actual longitudinal forces acting on the tool pack components. This may involve determining a mathematical conversion function that takes the electrical signals as input and provides a corresponding force as output. In some cases, this function may consist of a multiplication factor used to scale the electrical signals by a certain amount. Calibration is generally required for accurate measurements because the ratio of forces transferred to the load cells 237A-C will vary depending on how the adapter plate 225 is mounted and / or the transfer of forces from the mold may vary depending on how the tool pack is configured, e.g., what "pressure" is applied to the tool pack (see below).

[0045] To calibrate the load cells 237A-C, a fixture containing one or more reference load cells (not shown) can be mounted within the cradle 220 (e.g., in place of one of the spacer rings or ironing molds). A load is then applied to the reference load cells along axis A-A', and the electrical signals produced by the load cells 237A-C and the reference load cells are measured. A transfer function is then determined from the measured signals, for example, by fitting a polynomial or spline interpolation function to the reference signals plotted against the load cell signals. The load applied to the reference load cells and load cells 237A-C can be generated by a tool pack clamp 241 (see FIG. 2 ), which provides a compressive load between the adapter plate 225 and the front wall 239 of the housing 219. A percentage of this load (called "preload") is applied when the bodymaker 101 is actuated to rigidly and properly secure the tool pack components. Calibration of the load cells 237A-C can therefore be used to offset (i.e., compensate for) variations in pressurization between can body manufacturers. Calibration of the load cells 237A-C also allows the portion of the longitudinal load that bypasses the load cells 237A-C through the pressurization bolt 301B to be compensated for.

[0046] Force measurements obtained from the load cells 237A-C during can making can be analyzed using machine learning, analytics, and / or artificial intelligence techniques to determine how, for example, one or more operating parameters of the can body maker can be adjusted to improve the operation of the can body maker. For example, an evolutionary algorithm (or another type of optimization algorithm) can be used to modify the operating parameters of the can body maker according to a fitness metric based on the measured forces, such as a fitness metric that penalizes measured forces that exceed a predefined threshold and / or forces measured by the load cells 237A-C that differ from each other by a predefined threshold or relative percentage.

[0047] The operating parameters for the can bodymaker provided to the algorithm may include one or more of: the can making rate (the set speed of the can bodymaker), the operating temperature of the tool pack, the rate at which coolant is supplied to the tool pack, the rate at which lubricant is supplied to the tool pack, and the position (alignment) of the domer relative to the axis of the ram. The algorithm may also take as input other types of data, such as the time since the can bodymaker was last serviced or reconfigured, the number of cans made using the current set of molds, and / or measurements of the quality of the feedstock, such as the thickness or weight of the cups supplied to the bodymaker.

[0048] Feedback control can also be used to adjust one or more of the operating parameters of the can body maker to compensate for changes in the can body maker over time caused by wear or movement of components within the can body maker. For example, a proportional-integral-derivative (PID) controller can be used to change one or more of the operating parameters of the can body maker to minimize an error signal determined from the measured force.

[0049] 8 illustrates steps involved in a method of operating a can body maker to mitigate the effects of tool wear, damage, and / or misalignment during the production of can bodies using the can body maker described above, for example. A first step 801 involves obtaining output signals from one or more load cells 237A-C indicative of the axial force acting on the tool due to the cup passing therethrough, the load cells being located in or on an adapter plate 225 attached to the bolster plate 223 of the can body maker. These output signals are then processed in 802 to obtain data indicative of one or more of the tools being worn, damaged, and / or misaligned with respect to the ram 106. This may involve, for example, determining that the force due to the cup acting on the tool exceeds a threshold, or that the output signals obtained from two or more of the load cells are different and the difference or ratio thereof exceeds a predetermined threshold. One or more operating parameters of the can body maker, or another component of the production line in which the body maker is located, are adjusted at 803 based on the data to mitigate the effects of one or more tools that are worn, damaged, and / or misaligned with respect to the ram 106. This process can be repeated iteratively in a feedback loop at 804, as described above.

[0050] As will be appreciated by those skilled in the art, various modifications can be made to the above-described embodiments without departing from the scope of the present invention. [Explanation of symbols]

[0051] 101 Modular Body Maker, Can Body Maker, Body Maker 102 base 103 Machine Bed 105 Thrust assembly 106 Goad 107 Tool Pack 108 Bottom forming tool 109 Dorma Module 110 Can discharge turret 111 Infeed-Discharge Module 112 Redraw Sleeve Module 113 Support structure 114 Feeding mechanism 115 Redrawn Sleeve 116 Redraw carriage 117a Push rod 117b Push rod 201 Body Maker, Can Body Maker 210 Can discharge turret 212 Redraw Sleeve Module 219 Housing, Tool Pack Housing 220 Cradle, Tool Pack Cradle 221 Stripper assembly 223 Bolster Plate 225 adapter plate 226A Spacer Ring 226B Spacer Ring 229 Wear Bar 233 Stripper 235 Stripper housing 237A Load Cell 237A-C Load Cell 239 Front wall 241 Tool Pack Clamp 273A-C Load Cell 301 Annular 301A Cylinders and annular bodies 301B Pressurized bolt, annular, pressurized 401A, B Eddy Current Sensor A-A' axis

Claims

1. A can body maker for manufacturing a can body from a cup, a ram configured for reciprocal movement along an axis; a punch mounted on the ram; a tool pack including a cradle and a plurality of tools located within the cradle for squeezing and squeezing a cup mounted on the punch during forward travel of the ram; a bolster plate providing a rear wall of the tool pack; an adapter plate secured to the bolster plate; a stripper assembly secured to the adapter plate for removing the can body from the punch during the return stroke of the shove; a clamping mechanism for biasing the tool against a front surface of the adapter plate; one or more load cells located in or on the adapter plate and configured to generate one or more output signals indicative of the axial force acting on the tool due to the cup passing therethrough; This includes can body manufacturers.

2. 10. The can body maker of claim 1, including an encoder configured to provide a measurement of the position of the poker one or more times during each reciprocation.

3. 3. The can bodymaker of claim 2, wherein the encoder is a linear encoder.

4. 3. The can bodymaker of claim 2, wherein the encoder is a rotary encoder configured to be rotated by a shaft used to drive the tamper.

5. 10. The can bodymaker of claim 1, wherein the one or more load cells are piezoelectric load cells.

6. 2. The can bodymaker of claim 1, wherein the one or more load cells include two or more load cells, the load cells being equally angularly spaced from one another about the axis.

7. 10. The can body maker of claim 1, including a processor configured to adjust one or more operating parameters of the can body maker, such as a speed of reciprocating movement of the poker, in response to the one or more output signals.

8. 2. The can bodymaker of claim 1, wherein the adapter plate is secured to the bolster plate by one or more pressure bolts, each pressure bolt passing through a corresponding one of the load cells and securing the load cell between the adapter plate and the bolster plate.

9. 2. The can bodymaker of claim 1, wherein the stripper assembly includes a radial offset monitor for detecting misalignment of the tack and / or punch relative to the axis.

10. 10. The can bodymaker of claim 9, wherein the radial offset monitor includes a bore configured to allow passage of the punch and tamping rod, and one or more spaced eddy current sensors about the bore.

11. 1. An apparatus for retrofitting a can body maker, the apparatus comprising: a ram configured for reciprocal movement along an axis; a punch mounted on the ram; a tool pack including a cradle and a plurality of tools located within the cradle for squeezing and squeezing a cup mounted on the punch during forward travel of the ram; a bolster plate providing a rear wall of the tool pack; an adapter plate secured to the bolster plate; a stripper assembly for removing the can body from the punch during the return stroke of the shove; a clamping mechanism for biasing the tool against a front surface of the adapter plate; and wherein the device comprises: a replacement adapter plate for fastening to the bolster plate in place of the can bodymaker's adapter plate; one or more load cells located in or on the replacement adapter plate and configurable to generate one or more output signals indicative of the axial force acting on the tool by the cup passing therethrough; a stripper assembly for securing to the replacement adapter plate and for removing the can body from the punch during the return stroke of the shove; The device includes:

12. 12. The apparatus of claim 11, wherein the replacement adapter plate includes a stripper assembly including a radial offset monitor for detecting misalignment of the tampers and / or punches with respect to the axis.

13. 13. The apparatus of claim 12, wherein the radial offset monitor includes a bore configured to allow passage of the punch and tamping rod, and one or more eddy current sensors spaced about the bore.

14. 12. A method of calibrating the apparatus of claim 11 after it has been retrofitted to a can body maker, comprising: mounting a calibration fixture within the cradle of the can bodymaker, the calibration fixture including one or more reference load cells configured to generate one or more output signals indicative of axial forces acting on the tool located within the cradle; applying an axial force to the tool and one or more reference load cells using the clamping mechanism of the can bodymaker; determining a calibration factor or function using the one or more output signals of each of the one or more reference load cells to estimate the forces on the one or more tools from the output signals generated by the one or more load cells of the apparatus; The method includes:

15. 1. A method of operating a can bodymaker that reduces the effects of tool wear, damage, and / or misalignment during the production of can bodies, wherein each can body is formed by pushing a cup attached to an axially reciprocating ram punch through a tool housed in a cradle in a tool pack of the can bodymaker; obtaining an output signal indicative of an axial force acting on the tool by the cup passing therethrough from one or more load cells located in or on an adapter plate attached to a bolster plate providing a rear wall of the tool pack; processing the output signals to obtain data indicative of one or more of the tools being worn, damaged, and / or misaligned with respect to the tack; adjusting one or more operating parameters of the can body maker or another component of the production line in which the can body maker is located based on the data to mitigate the effects of the one or more tools being worn, damaged, and / or misaligned with respect to the tampers; It encompasses The can bodymaker includes a stripper assembly attached to the adapter plate for removing the can body from the punch during the return stroke of the shovel.

16. The one or more operating parameters are: Can making rate and an operating temperature of the tool pack; and a supply rate or temperature of coolant to the tool pack; a supply rate of lubricant to the tool pack; and the position of the domer relative to the axis of said ram; 16. The method of claim 15, comprising one or more of:

17. 16. The method of claim 15, wherein the one or more operating parameters include parameters of a component of the production line upstream or downstream of the can bodymaker, such as a cup press.

18. 16. The method of claim 15, including using a stripper secured to the adapter plate to remove the can body from the punch during the return stroke of the shod rod.

19. 20. The method of claim 18, wherein the stripper is provided in a stripper assembly including a radial offset monitor, the method further comprising: using the radial offset monitor to obtain an output signal indicative of a position of the tamping rod and / or punch perpendicular to the axis; and adjusting the one or more operating parameters based on the data and the output signal obtained from the radial offset monitor.

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