The embodiments described and claimed herein relate generally to bottom forming methods, systems, and devices for can manufacturing.
The present embodiments relate generally to assemblies used in the manufacture of metal containers. In the bottom forming process, there are a number of critical alignments and forces that affect the quality and repeatability of making cans of acceptable quality. In prior systems, the set up of the bottom-forming machinery relied in large part to the skill and experience of the person setting up the machinery. To improve this, there is a need for equipment that removes the guesswork from the setup process and eliminates detrimental variances due to inaccurate measurements, wear and other factors.
In one aspect, an embodiment of the present system allows for positional adjustment of a bottom-former die set. Off-center hits from a can-forming punch can be detected using sensors, and as a result, the die set may be automatically or manually moved in a direction that more closely aligns the die set with the punch.
In another aspect, an embodiment allows for measurement and adjustment of air pressure that is in turn used to set or change the clamping force of the bottom former's clamp ring. The pressure can be automatically or manually adjusted to compensate for different can types, sizes, bottom geometry, etc.
In yet another aspect, an exemplary embodiment allows for the force applied by a dome-setting spring to be measured and adjusted, either manually or automatically. The measurement and adjustability provides the benefit of quantification of the setting force applied during the can-making process. In previous systems, the setting force was not measured, thus changes in the bottom former due to wear and age could have a detrimental impact on the quality of cans being produced.
The figures show a die set comprising a clamp ring 4 and a dome die 5. These act together, in conjunction with the can-forming punch 45, to form the structure of the bottom of a two-piece can.
Still referring to
Assuming the punch 45 strikes the bottom former die set 4 & 5 perfectly straight along the center axis, the motion of the die set 4 & 5 will be straight back into the bottom former. This condition is ideal for can making, but not obtainable in practice due to wear and tear on the can making equipment, initial set up inaccuracies, equipment speed changes and other variables. The floating die set 4 & 5 is designed to “float” around the center axis to match the position of the punch 45 as it engages the bottom former die set 4 & 5. In some embodiments of a floating clamp ring design, the fit between the clamp ring 4 and the dome die 5 may be a taper. Such a taper fit allows the clamp ring to rock on the fixed dome die 5 to facilitate the alignment feature. As shown in the embodiment of
The processed signals from the strain sensors 38 can be utilized by the operator during initial equipment setup to align the bottom former to the punch. The data can also be utilized to monitor the alignment during the can making process to indicate process and equipment problems and maintenance requirements. The data can also be utilized for process trending.
Information from the strain sensors 38 can be utilized as well to make offset hit centering adjustments of the die set, within the bottom former itself, either manually or automatically in a feed-back loop. For example, the sensor information can be used to make adjustments to the position of the bottom former die set 4 & 5 dynamically during the can making process. As long as the sensors 38 continue to provide information that indicates punch 45 is making off-center hits, the information can be used to drive (electrically, pneumatically, or hydraulically) one or more of the actuators to improve the alignment of the die set 4 & 5 relative to the punch. As shown in
The actuators 44, through their linkage mechanisms 48, provide a linear force, in either direction, corresponding to the direction and distance required to center the bottom former die set 4 & 5 relative to the punch 45. In the case of manual manipulation, the offset hit information can be displayed for an operator to use during adjustment. To accomplish an adjustment of the x-y position of the dome die and clamp ring, the actuators 44 may be rotated or otherwise actuated, and movement of the linkage mechanisms 48 is transferred to the cross linkage shuttles 43. For example, if the top actuator in
The cross linkage shuttles 43 actuate the torsion rod linkages 42 through a common pin. As the torsion rod linkages 42 rotate, a torsional force is applied to the torsion bars 35. In the example described above, if the cross linkage shuttle moves up, a clockwise torsion will be applied to bar 35A, while a counterclockwise torsion will be applied to torsion bar 35C. It should be noted that, although a single, common shuttle 43 is shown, which can apply torque to two torsion bars at once, other configurations are possible. For example, an arrangement involving a single actuator providing torque to each torsion bar is possible.
The torsion bars 35 (four in the illustrated embodiment) extend through the die set sensing and adjustment assembly 2 to a position near the can-forming dies 4 & 5. The end of the torsion rod linkages 35 are formed in a manner to transfer the torsional force on them into a linear force that will act upon the sensor support tube 31 by way of a hole in the support tube through which the torsion rods pass near the bends in the rods. The linear force in turn moves die set 4 & 5 relative to the punch 45.
The torsion bar anchor ring 36 provides an anchor point for the opposing linear force produced by the torsion bars 35. The torsion bar anchor ring 36 is held in place in cylinder housing 7 (see
The actuating force from the torsion bars 35 is applied to the sensor support tube 31 near, and providing motion radially, to the die set 4 & 5. Referring to the torsion bar detail in
The torsion bars 35 can be utilized alone or in combination to provide the desired deflection distance and direction required to center the die set 4 & 5 to the punch, while at rest or during the can making process. Because the torsion bars 35 and the sensor support tube are mechanically allowed to deflect while in any operational position, the strain sensors 38 remain functional and continue to sense die set 4 & 5 position changes applied to them from the punch 45, such as from off-center hits. The torsion bar anchor ring 36 contains an anchor ring seal 37 that provides protection from coolant and lubricant intrusion into the mechanisms behind it. The anchor ring seal 37 also allows the sensor support tube 31 to deflect. The linkage cover 6 protects the mechanism from contaminants utilizing a cover seal 16 between the linkage cover 6 and the sensor support tube 31.
The sensor support tube 31 is hollow to allow the passage of trapped coolant and lubricants, that are used in the can making process, from the coolant relief ports 29 in the dome die, to the coolant exhaust port 30. The coolant and lubricant is then expelled from the bottom former through an opening in the cylinder housing exhaust port 47 (
Monitoring and Adjusting the Bottom Former Die Set Alignment
The die set sensing and adjustment assembly 2 in combination with the floating dome die 29 and the floating clamp ring 4 create a mechanism that allows adjustment to the alignment between the can-forming punch 45, the floating clamp ring 4 and the floating dome die 5. The changes in this alignment can be enacted either manually or automatically.
During the initial setup of the bottom former into the body-maker, standard mounting methods will be used. This will align the centerline of the can-forming punch 45 to the centerline of the floating clamp ring 4 and the floating dome die 5. This alignment is crucial to making proper cans. Any deviation of this alignment, in any direction, will adversely affect the quality and rate of production of cans through the body maker. During the can-making process, this alignment can shift due to many variables in the equipment. Variances in the speed of can production can also lead to misalignment problems.
The die set sensing and adjustment assembly 2 has a strain sensor array 38 surrounding a portion of the sensor support tube 31 as shown in
While the body maker is creating cans and the bottom former is creating the bottom geometry, the can-forming punch 45 alignment to the bottom former die set 4 & 5 may be monitored and displayed on the controller. This information can be displayed in such a fashion to allow the user to determine the direction and magnitude of the misalignment offset. As misalignment occurs during can production, the operator may manually adjust the alignment utilizing one or more of the actuator linkages 48, or the controller can send signals to one or more of the motion actuators 44 to adjust the alignment dynamically. This realignment process allows the can forming punch 45 to stay in alignment with the bottom former die set 4 & 5.
As the rate of can production through the body maker changes, the alignment between the can forming punch 45 and the bottom former die set 4 & 5 tends to change. Automatically readjusting the alignment can result in a higher rate of can production. In addition, the result of the components being aligned results in the creation of more cans within the proper specification. The alignment data collected can be stored and trended for determining longer term problems. These long-term problems may include body maker component wear, bottom former setup and alignment issues, bottom former components wear and variances in can material. The data can be stored and reproduced for use during change-out of can geometries and shared between body-makers and can plants.
Setting the Clamp Ring Force
During the bottom forming process, the punch 45, with the can material wrapped around it, strikes the clamp ring 4 first. As shown in
Clamp Ring Pressure Control
The air pressure supplied to the compressed air inlet 18 can be set either manually or automatically. Air pressure can be supplied from an air pressure regulator and adjusted, as needed, manually. The air pressure, in this configuration, can be manipulated manually if there are changes to the can size, can bottom configuration or bodymaker can production rate. This leaves open the possibility that unacceptable cans will be created after can style changeout or bodymaker speed changes during production. By adjusting the air pressure introduced into the compressed air inlet 18 automatically, the pressure on the floating clamp ring 4 can be modified during a can geometry change over, or bodymaker speed change, without operator intervention. During an adjustment, in the automatic configuration, the pressure is manipulated by a controller. The pressure to be sent to the bottom former can be specified through a programmed look-up table or manipulated and stored by the operator through the controller's interface. The controller can constantly measure the air pressure and make adjustments in a feedback loop. The lookup table in the controller also has stored pressure data that corresponds to differing bodymaker speeds and differing can geometries and styles. These pressure settings can be used to adjust the pressure in accordance to the speed of the bodymaker during operation, as well as differing can geometries. This allows the floating clamp ring 4 force to be manipulated dynamically, during can production, to assure cans are made to specification. If the pressure falls out of a programmed tolerance window at any time, a fault can be logged in the controller. This fault signal can be used to inform the operator that maintenance must be performed on the bottom former or other equipment such as the bodymaker. The controller can also monitor the flow of the air being sent to the bottom former through the compressed air inlet 18. If the air flow is measured higher than a preprogrammed level, an error condition can be logged to warn the operator of potential clamp ring pressure piston 17 wear.
Monitoring and Adjusting the Dome Setting Force
Referring again to
The force produced by the dome setting spring 10 (
Adjustments can be made to the dome setting force manually by loosening the force setting screw jam nut 21, adjusting the dome setting force by turning the spring force setting screw 20 in or out, and retightening the force setting screw jam nut to lock in the setting, which as discussed herein can be measured by sensor 27. The dome setting force can also be manipulated automatically by utilizing an electrical, pneumatic of hydraulic actuator. The dome setting force is critical to creating cans to the customer's specifications. This force, typically, is a set value and cannot vary during installation or operation. The ability to change this force, either during initial setup, can geometry changeover, or during the can-making operation, enhances the ability to produce better cans at any production speed.
By adjusting the dome setting force automatically, the force produced to set the dome in the bottom former can be modified during a can geometry change over, or bodymaker speed change, without operator intervention. During an adjustment, in the automatic configuration, the dome setting force is adjusted by the controller. The force to be sent to the bottom former can be specified by a programmed lookup table or manipulated and stored by the operator through the controller's interface. The controller is constantly measuring the force utilizing the force sensor 27 located in the setting force adjustment assembly 1 and making adjustments in a feedback loop. A lookup table in the controller also has stored force data that corresponds to differing bodymaker speeds. These force settings can be used to adjust the applied force in accordance to the speed of the bodymaker during operation. This allows the dome-setting force to be manipulated dynamically, during can production, to assure cans are made to specification. If the measured force falls out of a programmed tolerance window at any time, a fault can be logged in the controller. This fault signal can be used to inform the operator that maintenance must be performed on the bottom former or other equipment such as the bodymaker. The signal being received at the controller from the force sensor 27 can be analyzed for its signal shape. The shape of this waveform can be analyzed by the controller to indicate faults in the can making process induced by material changes, equipment components wear or other factors.
As the spring force setting screw 20 is advanced, increasing pressure is applied to the dome setting spring 10 through the force sensor 27 and the inner end plate 26. The adjustment can be locked in place with the force setting screw jam nut 21. A ball bearing 22 may be used to limit the torque applied to the force sensor during adjustment. The force sensor signal can be used to display the forces applied by the dome setting spring 10 or be processed to show the forces obtained throughout the over-travel event. This information can be fed back into the setting force adjustment assembly 1 for automatic adjustments required during operation. The force adjustment assembly 1 utilizes an inner environmental seal 23 and an outer environmental seal 24. These seals prevent coolant and lubricant from entering the force sensing and adjustment assembly 1, and also supply mechanical radial stability.
The setting force adjustment assembly allows the user to adjust the force being applied by the dome setting spring 10. During initial bottom former setup in the can plant, the user can adjust the amount of setting force, applied to the can material during the can-making process, by turning the spring force setting screw 20. The spring force setting screw 20 applies force to a force sensor 27. The force sensor 27 sends a signal to a device that displays the force readings. The user may then increase or decrease the setting force applied during the bottom-forming process. This benefits the user by being able to quantify the setting force being applied during the can making process. This knowledge is valuable for creating consistently accurate cans across all of the body maker machines in the can plant. The information can be used, as well, to bring consistency to multiple can plants if the data is shared between them.
The method for use, during initial bottom former setup, is to first assure the spring setting force screw 20 is backed out to the point that there is no force being applied to the dome setting spring 10. This is accomplished by backing out the setting force screw 20 and watching the displayed data from sensor 27 until the force displayed is near or at zero. The bottom former is then installed, and aligned, into the body maker in usual fashion. Assuring that the can forming punch 45 is retracted from the bottom former assembly, adjustments can be made to the setting force. These adjustments are made by turning the spring force adjustment screw 20 into the setting force adjustment assembly 1 while watching the force increase on the display. When the force reading on the display reaches the desired level, the adjustment is complete. If the body maker is to be changed over to create a different can geometry, the initial setting force can be changed to meet the requirements of the new can.
During the can-making process, the setting force may be monitored, at a high frequency, and displayed on the display unit as a pulse, for every can made, during the over-travel portion of the bottom forming process. The initial force, maximum force, and the presence of the force are monitored by the display unit. The data collected during the can making process can be utilized to indicate anomalies in the bottom former process. Changes to the initial setting force, as indicated by the level measured while not in over travel, and anomalies such as dome setting spring 10 wear may be witnessed. This allows the user to either adjust the force to a higher level or change the dome setting spring 10. Changes to the maximum force, as indicated by the measurement at the peak of the force pulse, may indicate anomalies such as can material thickness changes, body maker driveline equipment changes or other changes occurring in the process. These long-term problems may include body maker component wear, bottom former setup and alignment issues, bottom former component wear and variances in can material. The data can be stored and reproduced for use during change-out of can geometries and shared between body-makers and can plants.
The over-travel distance is measured through the use of an over travel distance sensor 11 (see
Number | Name | Date | Kind |
---|---|---|---|
5378010 | Marino | Jan 1995 | A |
5380028 | Ferris | Jan 1995 | A |
7124613 | McClung | Oct 2006 | B1 |
7290428 | Zauhar | Nov 2007 | B2 |
8434988 | Tonti | May 2013 | B2 |
20080302166 | Frattini | Dec 2008 | A1 |
20100251799 | Gogola | Oct 2010 | A1 |
20130037554 | Monro | Feb 2013 | A1 |
Number | Date | Country |
---|---|---|
WO 03072482 | Sep 2003 | WO |
Entry |
---|
PCT International Search Report and Written Opinion; PCT/US2018/013522; Printed & Received Mar. 18, 2018. |
Preliminary Report on Patentability for PCT/US2018/013522; Received Aug. 1, 2019. |
Number | Date | Country | |
---|---|---|---|
20180207706 A1 | Jul 2018 | US |