Monitorable and compensatable feedback tool and control system for a press

• US 4,945,742 A
• Filed: 08/12/1988
• Issued: 08/07/1990
• Est. Priority Date: 08/27/1987
• Status: Expired due to Term

• Current Assignee: The Minster Machine Company (Nidec Corporation)
• Original Assignee: The Minster Machine Company (Nidec Corporation)
• Inventors: Schoch, Daniel A.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US07/231,446
• Time in Patent Office: 725 Days
• Field of Search: 72/1, 72/19, 72/20, 72/21, 72/12, 72/37, 72/374, 72/453.13, 267/119, 267/130
• US Class Current: 72/17.2
• CPC Class Codes: B21D 51/383 scoring lines, tear strips or pulling tabs
• CPC Class Codes: B30B 15/0041 Control arrangements therefor
• CPC Class Codes: B30B 15/0094 Press load monitoring means B30B15/281 takes precedence

Abstract

A load control system and tool arrangements are disclosed for controlling the shutheight and back-up load on a mechanical press tool in response to a monitored or measured parameter indicative of press tool force or part quality, which monitored parameter is communicated to a controller for determination of a control signal to control a means for regulating the press tool back-up load and shutheight without interrupting press operations. The control system is operable to control a single station or multi station press and can be installed on either an individual press tool or the bolster or slide.

Claims

1. A method for monitoring and controlling a back-up load to at least one of an upper and lower tool in a press assembly comprising:

applying fluid at a pressure to said one tool to provide a back-up load thereto;

sensing the back-up load at said tool and producing a single signal correlated to the sensed load;

comparing a predetermined reference load signal and said sensed signal and producing an output control signal as a function only of said compared signals; and

dynamically controlling said fluid pressure and thereby said tool back-up load in response to only said control signal.

2. The method of claim 1 wherein the sensing of the back-up load is accomplished by sensing the fluid pressure applied to said one tool.

3. The method of claim 1 further comprising:

providing a display device; and

, coupling said output control signal to said display device for displaying said output control signal.

4. The method as claimed in claim 3 further utilizing said displayed output control signal for controlling said fluid pressure through a manually operable regulator valve.

5. In a press having a slide and bolster to which is attached tooling comprising a plurality of die stations, each die station performing a separate forming operation on a workpiece passing through the press, a method of controlling quality of the formed workpiece comprising:

moving a workpiece sequentially through said plurality of die stations,

sensing individual loads on the tooling in each of the die stations as the press is running and providing a single indication of each of said individual loads,

comparing the sensed loads with desired loads, and

while the press is running, modifying the back-up loads applied to those die stations where the sensed loads differ from the desired loads to achieve desired load conditions, the back-up loads for the die stations being modified independently of each other.

6. In a press having a slide and bolster to which is attached tooling comprising a plurality of die stations, each die station performing a separate forming operation on a workpiece passing through the press, a method of controlling quality of the formed workpiece comprising:

moving a workpiece sequentially through said plurality of die stations,

sensing the values of a plurality of predetermined dimensional parameters of the workpiece formed by the tooling that vary depending on the amount of force exerted on the workpiece by the tooling at the respective die stations,

comparing the sensed parameter values with desired parameter values, and

while the press is running, modifying back-up loads applied to those die stations where the sensed parameter values differ from the desired parameter values to achieve desired parameter values, said back-up loads for the die stations being modified independently of each other.

7. A method for monitoring and controlling a back-up load to a back-up load means with at least one of an upper tool and lower tool in a press assembly, said back-up load means including a fluid-backed tool support with at least one piston and cylinder arrangement, said upper tool and lower tool cooperating to define the shutheight therebetween, said method comprising:

applying fluid at a pressure to said piston and cylinder arrangement to provide a back-up load to said tool support;

sensing the back-up load at said least one of an upper tool and lower tool as the tools form a workpiece and producing a signal correlated to the sensed load;

comparing a predetermined reference load signal and said sensed signal and producing an output control signal as a function of said compared signals; and

utilizing said output control signal to control automatically said fluid pressure and said tool back-up load to elastically deform said tool support thereby varying said shutheight to thus control said tool load during forming of the workpiece.

8. In a press having tooling that performs a forming operation on a workpiece that passes through the press, a method for controlling the back-up force applied to the workpiece comprising:

applying a controllable back-up force to the tooling during forming of the workpiece,

sensing a predetermined parameter of the workpiece formed by the tooling that varies depending on the amount of force exerted on the workpiece by the tooling and producing a single sensed back-up load signal indicative of the force exerted on the workpiece that correlates to the value of the parameter that is sensed,

comparing the back-up load signal with a reference signal indicative of a back-up load that correlates to a desired value of said parameter, and

varying the back-up load applied to the tooling as the press is running in response to only the sensed and reference signals to achieve the desired tooling load and, therefore, the desired parameter value.

9. The method of claim 8 wherein the press tooling comprises a plurality of die stations that perform different forming operations on the workpiece and including:

sensing a plurality of parameters of the workpiece that vary depending on the force exerted on the workpiece at the respective die stations, and

independently controlling the back-up loads at the die stations in response to the sensed parameters.

10. The method as claimed in claim 8 wherein said tooling includes at least one upper tool and at least one lower tool, a fluid-backed bolster with one of said one upper tool and lower tool mounted on and operable therewith, said bolster having a fluid operable piston and cylinder back-up arrangement, said upper and lower tools defining a shutheight therebetween, said method further comprising:

varying the back-up load applied to said bolster through said cylinder and piston arrangement to elongate said bolster to vary the shutheight and thus control the load at said upper and lower tools during forming of said workpiece.

11. The method of claim 8 further comprising:

comparing the back-up load signal with a reference signal indicative of a back-up load signal that correlates to a desired value of said parameter,

producing an output control signal indicative of the compared sensed signal and reference signal, and

displaying said output control signal on a display device.

12. The method of claim 11 further comprising:

applying fluid at a pressure to provide said back-up force;

controlling said fluid at a pressure with a manually operable regulator; and

,

utilizing said displayed control output signal to vary said manually operable regulator to control said back-up force.

13. The method as claimed in claim 8 wherein said tooling comprises a plurality of tools and said method further comprises;

providing a controller means for receiving and comparing said sensed back-up load signal and reference signal, a manual input device and a display device, which controller means is coupled between the manual input device and the display device;

measuring by manual means said workpiece parameter;

entering said measured workpiece parameter to said controller means through said manual input device;

coupling a source of fluid at a pressure through a line to provide said back-up load, said fluid being nitrogen, said line including an intensifier means and a manually operable regulator valve, and said pressure is controllable to maintain a constant load to at least one tool of said plurality of tools;

displaying said compared back-up level signal and said reference signal on said display device; and

,

adjusting the fluid at a pressure to at least one of said plurality of tools by said manually operable regulator valve in response to said displayed signal while said press is running.

14. The method as claimed in claim 8 wherein said tooling comprises a plurality of tools, said method further comprising:

providing a controller means for receiving and comparing said sensed back-up load signal and reference signal, a manual input device, a display device and an automatically controllable regulator, which controller means is connected to said display device and coupled between the manual input device and the automatically controllable regulator means;

sensing by manual means said workpiece parameter which parameter is correlative to said back-up load parameter;

entering said sensed workpiece parameter to said controller means through said manual input device;

displaying said comparison of said back-up load signal and said reference signal or said display device;

coupling a source of fluid at a pressure through a line to provide said back-up load, said line including an intensifier means and said automatic regulator means therein; and

,

adjusting the fluid pressure to at least one tool of said plurality of tools by said automatic regulator in response to said compared signal from said controller.

15. The method as claimed in claim 8 wherein the press tooling comprises a plurality of tools to perform different forming operations on said workpiece;

providing said controllable back-up force by a variable fluid pressure circuit operable between a source of fluid at a pressure and back-up load means for providing said back-up force, said fluid circuit utilizing oil and including at least one variable regulating means;

providing a controller means, which is coupled to a display device for receiving and comparing said sensed predetermined workpiece parameter signal and said reference signal to provide an output signal;

displaying said output signal on said display device; and

,

manually adjusting said variable regulating means to control said fluid pressure and thus said back-up load in response to said displayed signal while said press is running.

16. The method as claimed in claim 8 wherein the press tooling comprises a plurality of tools to perform different forming operations on said workpiece;

providing said controllable back-up force by a variable fluid pressure circuit operable between a source of fluid at a pressure and back-up load means for providing said back-up load, said fluid circuit utilizing oil and including at least one variable regulating means;

providing a controller means coupled to a display device for receiving and comparing said sensed predetermined workpiece parameter signal and reference signal, said controller providing an output signal indicative of said compared workpiece and reference signals;

displaying said output signal on said display device;

coupling said controller means to said variable regulating means, which regulating means is operable to control said fluid pressure and said back-up load as a function of said output signal.

17. The method as claimed in claim 8 wherein the press tooling comprises a plurality of tools to perform different forming operations on said workpiece, said method further comprising;

monitoring said tool load with a load monitoring device;

providing said controllable back-up force by a variable fluid pressure circuit operable between a source of fluid at a pressure and back-up load means for providing said back-up load;

providing a controller means, which is coupled to a display device, for receiving and comparing said sensed parameter signal and said reference signal to provide an output signal, which sensed signal is automatically sensed by said sensing means;

displaying said output signal on said display device;

manually adjusting said variable regulation means while said press is running to control said fluid pressure and said back-up load as a function of said displayed output signal.

18. The method of claim 8 wherein said parameter is sensed by manual measurement and is input into a controller which in turn produces said back-up load signal.

19. The method of claim 18 wherein the step of varying comprises manually adjusting back-up pressure to the tooling.

20. A method for monitoring and controlling a back-up load to a tool means having a plurality of upper tools and a plurality of lower tools and a fluid-backed tool support having one of said plurality of upper and lower tools mounted thereon in a press assembly, said method comprising:

applying fluid at a pressure to said tool support to provide a back-up load to said plurality of tools thereon;

sensing the back-up load at least at one of said tools and producing a single signal correlated to the sensed load;

providing a display device;

comparing a predetermined reference load signal and said sensed signal and producing and displaying an output control signal on a display device as a function only of said compared signals; and

controlling said fluid pressure and thereby said tool back-up load in response to said control signal.

21. The method as claimed in claim 20 further utilizing said displayed output control signal for controlling said fluid pressure through a manually operable regulator valve.

22. In a press having a plurality of upper tools and lower tools, for performing forming operations on a workpiece passing through the press, which upper tools and lower tools define a shutheight therebetween, and a fluid-backed tool support coupled to a source of fluid at a pressure with a manually-operable regulator valve therebetween, a method for controlling the shutheight and thus the back-up force applied to the workpiece, said method comprising:

applying a controllable back-up force to said tool support during the forming operations on said workpiece;

sensing a predetermined parameter of the workpiece formed by the tooling that varies depending upon the amount of force exerted on the workpiece by the tooling;

producing a sensed back-up load signal indicative of the force exerted on the workpiece that correlates to the value of the sensed parameter;

comparing the back-up load signal with a reference signal indicative of a back-up load correlative to a desired value of said parameter;

producing and displaying an output control signal indicative of said compared signals; and

varying, by said manual regulator, the fluid pressure applied to said tool support to elongate said tool support thereby varying said shutheight and thus said back-up load at said tools.