Systems and methods for determining characteristics of a workpiece in a plasma arc processing system

Patent metadata

Field	Value
Publication number	US-11890693-B2
Application number	US-202117205821-A
Country	US
Kind code	B2
Filing date	Mar 18, 2021
Priority date	Mar 18, 2020
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

A computerized method is provided for automatically determining at least one characteristic of a workpiece for processing by a plasma arc processing system. The method includes electrically connecting the workpiece to the plasma arc processing system that includes a plasma arc torch. A distal tip of the plasma arc torch is configurable to be positioned proximate to the workpiece. The method includes supplying, by the plasma arc processing system, an electrical current with a low amperage to the workpiece, the low amperage current insufficient to cut the workpiece, and monitoring, by the plasma arc processing system, a path of the electrical current relative to the workpiece. The method further includes determining, by the plasma arc processing system, the at least one characteristic of the workpiece based on the electrical current path monitored.

First claim

What is claimed is:

1. A computerized method for automatically determining at least one characteristic of a workpiece for processing by a plasma arc processing system, the method comprising:
electrically connecting the workpiece to the plasma arc processing system that includes a plasma arc torch, wherein a distal tip of the plasma arc torch is configurable to be positioned proximate to the workpiece;
supplying, by the plasma arc processing system, an electrical current with a low amperage to the workpiece, the low electrical amperage current insufficient to cut the workpiece;
monitoring, by a processor of the plasma arc processing system, a path of the electrical current relative to the workpiece; and
determining, by the processor of the plasma arc processing system, the at least one characteristic of the workpiece based on the electrical current path monitored.

2. The computerized method of claim 1 , further comprising adjusting a cutting or marking process to be performed on the workpiece by the plasma arc torch based on the at least one characteristic of the workpiece determined.

3. The computerized method of claim 1 , wherein the plasma arc processing system supplies the electrical current to the workpiece via a plasma arc generated by the plasma arc torch.

4. The computerized method of claim 3 , further comprising supporting, by the plasma arc torch, the plasma arc with a non-oxidizing gas.

5. The computerized method of claim 3 , further comprising:
translating the plasma arc torch relative to the workpiece;
generating, by the plasma arc torch, the plasma arc during the torch translation; and
monitoring the path of the electrical current carried by the plasma arc as the plasma arc torch translates relative to the workpiece over time,
wherein the at least one characteristic of the workpiece is a boundary of the workpiece determined based on variations in the monitored electrical current path over time during the translation.

6. The computerized method of claim 5 , wherein determining the path of the electrical current comprises determining if the electrical current travels through the workpiece or through a nozzle of the plasma arc torch without contacting the workpiece.

7. The computerized method of claim 6 , wherein the electrical current traveling through the workpiece indicates the plasma arc impinging on the workpiece and the electrical current returning without contacting the workpiece indicates the plasma arc encountering a void region within an outer boundary of the workpiece or beyond the outer boundary of the workpiece.

8. The computerized method of claim 7 , further comprising adjusting a direction of translation of the plasma arc torch before the plasma arc torch translating more than a predefined distance into the void region.

9. The computerized method of claim 7 , wherein the plasma arc impinging on the workpiece marks the workpiece without cutting the workpiece.

10. The computerized method of claim 5 , further comprising mapping a perimeter of the workpiece by translating the plasma arc torch in at least one of a substantially serpentine or stepwise path relative to the workpiece.

11. The computerized method of claim 3 , wherein the at least one characteristic of the workpiece determined comprises a threshold of supplied electrical current at or above which the electrical current path travels through the workpiece such that the plasma arc marks the workpiece.

12. The computer method of claim 11 , further comprising:
translating the plasma arc torch relative to the workpiece;
generating, by the plasma arc torch, the plasma arc during the torch translation; and
controllably increasing or decreasing the electrical current supplied by the plasma arc torch relative to the threshold electrical current while translating the plasma arc torch to mark a desired pattern on the workpiece.

13. The computer method of claim 12 , wherein decreasing the electrical current below the threshold electrical current electrically disconnects the plasma arc from the workpiece to prevent marking of the workpiece, such that the electrical current path returns through a nozzle of the plasma arc torch without contacting the workpiece.

14. The computerized method of claim 11 , wherein the threshold electrical current is 5 amps.

15. The computerized method of claim 1 , wherein the plasma arc processing system supplies the electrical current to the workpiece via a work clamp connected to the plasma arc processing system.

16. The computer method of claim 15 , wherein the work clamp includes a sensor configured to determine a thickness of the workpiece based on the electrical current path.

17. The computer method of claim 15 , wherein the at least one characteristic of the workpiece is one of thickness, resistivity or material type of the workpiece.

18. The computer method of claim 15 , wherein the work clamp includes at least two wires for delivering the electrical current to the workpiece.

19. The computer method of claim 15 , further comprising controlling the supply of the electrical current to the workpiece via the work clamp using a switch of the plasma arc processing system in electrical communication with the work clamp, the switch configured to (i) permit the electrical current to flow through the work clamp for determining the at least one characteristic of the workpiece or (ii) prevent the supply of the electrical current to the work clamp such that the work clamp electrically grounds the workpiece.

20. A computer-implemented plasma arc processing system for automatically determining at least one characteristic of a workpiece for processing the workpiece in accordance with the method of claim 1 , the system comprising:
a work clamp configured to secure to the workpiece in preparation for processing by the plasma arc torch; and
a power supply in electrical communication with the plasma arc torch and the work clamp, the power supply configured to supply the low-amperage electrical current to the workpiece, the low amperage electrical current insufficient to cut the workpiece;
wherein the processor is in electrical communication with the plasma arc torch, the work clamp and the power supply, the processor configured to monitor the path of the electrical current relative to the workpiece and determine the at least one characteristic of the workpiece based on the electrical current path monitored.

21. The computer-implemented plasma arc processing system of claim 20 , wherein the power supply is configured to supply the electrical current via a plasma arc generated by the plasma arc torch.

22. The computer-implemented plasma arc processing system of claim 21 , further comprising a motion device connected to the plasma arc torch and in electrical communication with the processor, the motion device configured to translate the plasma arc torch relative to the workpiece while the plasma arc torch generates the plasma arc.

23. The computer-implemented plasma arc processing system of claim 22 , wherein the processor is configured to monitor the path of the electrical current carried by the plasma arc as the plasma arc torch translates relative to the workpiece over time to determine a boundary of the workpiece based on variations of the electrical current path monitored during the translation.

24. The computer-implemented plasma arc processing system of claim 23 , wherein the processor determines the path of the electrical current by determin

Assignees

• Hypertherm Inc

Inventors

• Peters John
• Ortakales Jeff
• Milaneschi Mirko
• Labrecque Dana
• Leblanc Norman
• Robinson Richard Glen
• Hansen Brett A
• Gkatzimas Georgios E

Classifications

• B23K10/006 Primary

  Control circuits therefor · CPC title

• H05H1/3494

  Means for controlling discharge parameters · CPC title

• H05H1/36

  Circuit arrangements (H05H1/38, H05H1/40 take precedence) · CPC title