Detailed die process severity analysis and optimization methodology

• US 6,466,840 B1
• Filed: 11/01/1999
• Issued: 10/15/2002
• Est. Priority Date: 11/03/1998
• 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): NOLAND, THOMAS
• Application Number:
  US09/431,355
• Time in Patent Office: 1,079 Days
• Field of Search: 700/206, 702/56, 702/113, 702/189, 702/190, 735/93, 735/79, 73/110.1, 73/120.1, 736/49, 736/58, 738/699, 100/99, 100/48, 100/43
• US Class Current: 700/206
• CPC Class Codes: B30B 15/28 Arrangements for preventing distortion of, or damage to, presses or parts thereof
• CPC Class Codes: G05B 19/4065 Monitoring tool breakage, life or condition
• CPC Class Codes: G05B 2219/37435 Vibration of machine
• CPC Class Codes: G05B 23/0232 based on qualitative trend analysis, e.g. system evolution

Abstract

A system is provided for monitoring the operation of a press machine over a series of press running cycles. A plurality of press operating events associated with the operation of the press machine are defined. Each press operating event has a modifiable control function associated therewith. An arrangement of accelerometers measures the press machine vibrational activity associated with each press operating event that occurs during the series of press running cycles. A processor processes the vibration measurements associated with the press operating events to identify the presence of a vibration trend therein meeting a defined trending criteria. A controller is responsive to trend identification signals generated by the processor for modifying the respective control function of each press operating event which is associated with identification of the vibration trend.

Claims

1. A method of monitoring the operation of a press machine, comprising the steps of:

running the press machine through a plurality of press running cycles;

defining a plurality of press operating events associated with the operation of said press machine, each respective one of said plurality of press operating events having a modifiable control function associated therewith;

providing for each respective one of said plurality of press operating events a respective measure of the vibrational activity associated therewith present in the press machine during each respective one of said plurality of press running cycles and generating a respective vibration measurement signal representative thereof;

processing the respective vibration measurement signals associated with each respective one of said plurality of press operating events to identify the presence of a vibration trend therein meeting a defined trending criteria; and

modifying the respective control function of each press operating event determined by said processing step to be associated with the identification of said vibration trend.

2. The method as recited in claim 1, wherein said plurality of press operating events includes stripper plate impact on the downstroke of the press machine slide, punch impact on a workpiece, snap-through activity, and stripper plate impact on the upstroke of the press machine slide.

3. The method as recited in claim 1, wherein said step of providing vibrational activity measurements further includes the step of:

providing at least one accelerometer coupled to said press machine.

4. The method as recited in claim 1, wherein said defined trending criteria involves a rate of change in the vibration measurement signals exceeding a predetermined threshold level.

5. The method as recited in claim 1, wherein the step of running the press machine through a plurality of press running cycles further includes the step of varying the press running speed.

6. The method as recited in claim 1, wherein the step of running the press machine through a plurality of press running cycles further includes the step of varying the load developed within said press machine.

7. A method of monitoring the operation of a press machine, comprising the steps of:

running the press machine through a plurality of press running cycles;

providing a respective measure of the vibrational activity present in said press machine during each respective one of said plurality of press running cycles and generating a respective vibration measurement signal representative thereof;

defining a plurality of press operating events associated with the operation of said press machine, each respective one of said plurality of press operating events having a modifiable control function associated therewith;

resolving the respective vibration measurement signal associated with each respective one of said plurality of press running cycles into a corresponding set of component vibration signals each associated with a respective one of said plurality of press operating events;

processing the respective set of component vibration signals associated with each respective one of said plurality of press running cycles to identify the presence of a vibration trend therein meeting a defined trending criteria, the identification of said vibration trend being made in relation to component vibration signals associated with the same press operating event; and

modifying the respective control function of each press operating event which corresponds to the component vibration signals associated with identification of said vibration trend.

8. The method as recited in claim 7, further includes the steps of:

correlating the respective vibration measurement signal associated with each respective one of said plurality of press running cycles to a preselected press operating parameter; and

correlating the occurrence of each respective one of said plurality of press operating events to said preselected press operating parameter.

9. The method as recited in claim 8, further includes the step of:

correlating the respectively corresponding set of component vibration signals of each respective vibration measurement signal to respective ones of said plurality of press operating events based upon the vibration measurement signal correlation involving said preselected press operating parameter and the press operating event correlation involving said preselected press operating parameter.

10. The method as recited in claim 9, wherein said preselected press operating parameter includes a measure of the press machine slide displacement relative to bottom dead center.

11. The method as recited in claim 7, wherein said plurality of press operating events includes stripper plate impact on the downstroke of the press machine slide, punch impact on a workpiece, snap-through activity, and stripper plate impact on the upstroke of the press machine slide.

12. The method as recited in claim 7, wherein said step of providing vibrational activity measurements further includes the step of:

providing at least one accelerometer coupled to said press machine.

13. The method as recited in claim 7, wherein said defined trending criteria involves a rate of change in the component vibration signals exceeding a predetermined threshold level.

14. The method as recited in claim 7, wherein the step of running the press machine through a plurality of press running cycles further includes the step of varying the press running speed.

15. The method as recited in claim 7, wherein the step of running the press machine through a plurality of press running cycles further includes the step of varying the load developed within said press machine.

16. A system for monitoring the operation of a press machine over a plurality of press running cycles, comprising:

means for defining a plurality of press operating events associated with the operation of said press machine, each respective one of said plurality of press operating events having a modifiable control function associated therewith;

measurement means for providing, with respect to each one of said plurality of press operating events, a respective measure of the vibrational activity associated therewith present in the press machine during each one of said plurality of press running cycles and for generating a respective vibration measurement signal representative thereof;

processor means for processing the respective vibration measurement signals associated with each respective one of said plurality of press operating events to identify the presence of a vibration trend therein meeting a defined trending criteria and to generate trend identification signals representative thereof; and

controller means, responsive to the trend identification signals generated by said processor means, for modifying the respective control function of each press operating event associated with identification of said vibration trend.

17. The system as recited in claim 16, wherein said plurality of press operating events includes stripper plate impact on the downstroke of the press machine slide, punch impact on a workpiece, snap-through activity, and stripper plate impact on the upstroke of the press machine slide.

18. The system as recited in claim 16, wherein said measurement means further includes at least one accelerometer coupled to said press machine.

19. The system as recited in claim 16, wherein said defined trending criteria involves a rate of change in the vibration measurement signals exceeding a predetermined threshold level.

20. The system as recited in claim 16, wherein the press running speed is varied over said plurality of press running cycles.

21. The system as recited in claim 16, wherein the load developed within said press machine is varied over said plurality of press running cycles.

22. A system for monitoring the operation of a press machine over a plurality of press running cycles, comprising:

measurement means for providing a respective measure of the vibrational activity present in said press machine during each respective one of said plurality of press running cycles and for generating a respective vibration measurement signal representative thereof;

means for defining a plurality of press operating events associated with the operation of said press machine, each respective one of said plurality of press operating events having a modifiable control function associated therewith;

signal resolving means for resolving the respective vibration measurement signal associated with each respective one of said plurality of press running cycles into a corresponding set of component vibration signals each associated with a respective one of said plurality of press operating events;

processor means for processing the respective set of component vibration signals associated with each respective one of said plurality of press running cycles to identify the presence of a vibration trend therein meeting a defined trending criteria and to generate trend identification signals representative thereof, wherein the identification being made in relation to component vibration signals associated with the same press operating event; and

control means, responsive to the trend identification signals generated by said processor means, for modifying the respective control function of each press operating event which corresponds to the component vibration signals associated with identification of said vibration trend.

23. The system as recited in claim 22, further comprises:

a first correlation means for correlating the respective vibration measurement signal associated with each respective one of said plurality of press running cycles to a preselected press operating parameter and for generating a first correlation signal group representative thereof; and

a second correlation means for correlating the occurrence of each respective one of said plurality of press operating events to said preselected press operating parameter and for generating a second correlation signal group representative thereof.

24. The system as recited in claim 23, further comprises:

a third correlation means, responsive to the first correlation signal group generated by said first correlation means and to the second correlation signal group generated by said second correlation means, for correlating the respectively corresponding set of component vibration signals of each respective vibration measurement signal to respective ones of said plurality of press operating events.

25. The system as recited in claim 24, wherein said preselected press operating parameter includes a measure of the press machine slide displacement relative to bottom dead center.

26. The system as recited in claim 22, wherein said plurality of press operating events includes stripper plate impact on the downstroke of the press machine slide, punch impact on a workpiece, snap-through activity, and stripper plate impact on the upstroke of the press machine slide.

27. The system as recited in claim 22, wherein said measurement means further comprises:

at least one accelerometer coupled to said press machine.

28. The system as recited in claim 22, wherein said defined trending criteria involves a rate of change in the component vibration signals exceeding a predetermined threshold level.

29. The system as recited in claim 22, wherein the press running speed is varied over said plurality of press running cycles.

30. The system as recited in claim 22, wherein the load developed within said press machine is varied over said plurality of press running cycles.