Method for precision temperature controlled hot forming

• US 6,223,573 B1
• Filed: 06/25/1999
• Issued: 05/01/2001
• Est. Priority Date: 06/25/1999
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Couture, Richard L., Demichele, Stephen R., Grewal, Sukhminder S.
• Primary Examiner(s): TOLAN, EDWARD THOMAS
• Application Number:
  US09/340,271
• Time in Patent Office: 676 Days
• Field of Search: 72/16.1, 72/16.2, 72/16.5, 72/17.3, 72/18.1, 72/18.3, 72/19.1, 72/342.5, 72/342.6, 72/342.94, 72/352, 72/358, 72/364, 72/37, 29/889, 29/889.6, 29/889.7
• US Class Current: 72/19.1
• CPC Class Codes: B21C 51/00 Measuring, gauging, indicating, counting, or marking devices specially adapted for use in the production or manipulation of material in accordance with subclasses B21B - B21F
• CPC Class Codes: B21J 13/00 Details of machines for forging, pressing, or hammering
• CPC Class Codes: B21J 13/08 Accessories for handling work or tools
• CPC Class Codes: B21J 5/02 Die forging; Trimming by making use of special dies ; Punching during forging
• CPC Class Codes: B21J 9/20 Control devices specially adapted to forging presses not restricted to one of the preceding subgroups

Abstract

Methods and apparatus for operating a press, such as a forge or trim press, are directed at activating a ram in a press having a lower die and an upper die connected to a ram by heating a workpiece to a first temperature above an impact temperature. The workpiece then is placed on the lower die, monitored during chill down of the workpiece from the first temperature, and the ram actuated based upon the monitoring in a controlled manner to effect an impact of the upper die against the workpiece. The monitoring includes measuring a characteristic parameter of the workpiece and the actuating includes actuating the ram after a predetermined fixed value of the measured parameter is measured. The placing of the workpiece on the lower die is done manually in the preferred embodiment. In a more particular embodiment, the characteristic parameter is a contact time period of the workpiece with the lower die and the measuring includes starting to measure the contact time period of the workpiece with the lower die as soon as contact is made between the workpiece and the lower die, and actuating the ram to effect the impact occur at a predetermined fixed period of time after the contact is made.

Claims

1. A method for activating a ram in a press having a lower die and an upper die connected to a ram, said method comprising:

heating a workpiece to a first temperature above an impact temperature,

placing the heated workpiece on the lower die,

monitoring the workpiece during chill down of the workpiece from the first temperature, and

actuating the ram based upon said monitoring in a controlled manner to effect an impact of the upper die against the workpiece.

2. A method as claimed in claim 1 wherein said monitoring comprises measuring a characteristic parameter of the workpiece, and

said actuating the ram based upon said monitoring comprises actuating the ram after a predetermined fixed value of the measured parameter is measured.

3. A method as claimed in claim 2 wherein said placing the workpiece on the lower die is done manually.

4. A method as claimed in claim 3 wherein the characteristic parameter is a contact time period of the workpiece with the lower die and said measuring includes starting to measure the contact time period of the workpiece with the lower die as soon as contact is made between the workpiece and the lower die, and

actuating includes actuating the ram to effect said impact occur at a predetermined fixed period of time after the contact is made.

5. A method as claimed in claim 4 further comprising:

an operator manually placing the workpiece on the lower die with a holding tool,

having the tool make and stay in contact with a wire near the lower die as the workpiece is placed onto the lower die, and

the starting to measure the contact time period is initiated by completing an electrical starting circuit from the wire through the tool, the workpiece, and the lower die.

6. A method as claimed in claim 3 wherein the characteristic parameter is an actual transient temperature and said measuring comprises measuring the transient temperature with an infrared detector aimed at a predetermined and fixed position on the workpiece, and

actuating includes actuating the ram to effect said impact after a predetermined fixed temperature is sensed by the infrared detector.

7. A method as claimed in claim 3 wherein the characteristic parameter is a location of the workpiece on the lower die and said measuring comprises detecting whether the workpiece is at a predetermined and fixed location on the lower die, and

actuating the ram to effect said impact is initiated after the workpiece is at the predetermined and fixed location on the lower die.

8. A method as claimed in claim 7 wherein an electric eye is used to detect when the workpiece is at the predetermined and fixed location on the lower die and to start a timer to actuate the ram to effect said impact at a predetermined fixed period of time after the timer starts.

9. A method as claimed in claim 8 further comprising breaking a light curtain of the electric eye during the placing the unformed workpiece on the lower die and starting the timer by re-establishing the light curtain after placing the unformed workpiece on a lower die.

10. A press apparatus for forming a workpiece, said apparatus comprising:

a press hating spaced apart lower and upper dies,

said press having a ram operably connected to said upper die,

a measuring means for measuring a characteristic parameter of the unformed workpiece on said lower die during chill down of the workpiece from a first temperature above an impact temperature, and

a control means for actuating said ram to effect an impact of said upper die against the workpiece after a predetermined fixed value of said measured parameter is measured.

11. An apparatus as claimed in claim 10 wherein;

said characteristic parameter is a contact time period of the workpiece with said lower die and said measuring means includes a timing means for starting to measure the contact time period of the workpiece with said lower die as soon as contact is made between the workpiece and said lower die, and

said control means is operable to actuate said ram to effect the impact at a predetermined fixed period of time after the contact is made.

12. An apparatus as claimed in claim 11 further comprising:

a wire near said lower die, and

an electrical starting circuit including said wire for starting said timing means after said circuit is completed wherein said circuit includes in serial relationship said wire, said workpiece, and said die.

13. An apparatus as claimed in claim 11 further comprising:

a wire near said lower die,

an electrical starting circuit including said wire for starting said timing means after said circuit is completed,

a manually operated holding tool for an operator to place the workpiece on said lower die, and

said circuit having in serial relationship said wire, said tool, said workpiece, and said die.

14. An apparatus as claimed in claim 10 wherein;

said characteristic parameter is an actual transient temperature,

and said measuring means includes an infrared detector aimed to locate a predetermined and fixed position on the workpiece, and

said control means is operable for actuating said ram to effect the impact after said predetermined fixed temperature is sensed by said infrared detector.

15. An apparatus as claimed in claim 10 wherein;

said characteristic parameter is a location of the workpiece on said lower die,

and said measuring means includes a location detecting means for detecting whether the workpiece is at a predetermined and fixed location on said lower die, and

said control means is operable for actuating the ram to effect said impact after the workpiece is detected at said predetermined and fixed location on the lower die.

16. An apparatus as claimed in claim 15 wherein;

said position detecting means includes an electric eye,

said control means is operable to detect when the workpiece is at the predetermined and fixed location on said lower die and start a timer, and

said timer is operable to actuate said ram to effect the impact at a predetermined fixed period of time after said timer starts.

17. An apparatus as claimed in claim 16 wherein said control means is operable to detect a breaking of a light curtain of said electric eye when workpiece is placed on said lower die and starting said timer when said light curtain is re-established after the workpiece is placed on said lower die.