Workpiece edge detection using plasma arc cutting system

Patent metadata

Field	Value
Publication number	US-9630273-B2
Application number	US-201615173537-A
Country	US
Kind code	B2
Filing date	Jun 3, 2016
Priority date	Jun 4, 2015
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

Systems and methods can be provided to use an automated cutting system to identify an edge or multiple edges of a workpiece. An automated cutting system receives trace data for a test path to be traced over a workpiece. The automated cutting system includes a torch from which gas is flowed. The torch is controlled in accordance with the trace data to trace the test path over the workpiece. A set of back pressure values are obtained by monitoring a back pressure of the gas during the tracing of the path. The back pressure values are mapped to a set of coordinates. An edge of the workpiece is identified using the set of back pressure values and the set of coordinates.

First claim

What is claimed is:

1. A computer program product, tangibly embodied in a non-transitory, computer-readable storage device, for identifying an edge of a workpiece, the computer program product including instructions operable to cause an automated cutting system to:
receive trace data for a test path to be traced over the workpiece;
flow a gas from a torch of the automated cutting system;
control the torch in accordance with the trace data to trace the test path over the workpiece;
obtain a set of back pressure values by monitoring a back pressure of the gas during the tracing of the path;
map the set of back pressure values to a set of coordinates; and
identify an edge of the workpiece using the set of back pressure values and the set of coordinates.

2. The computer program product of claim 1 wherein the gas comprises air.

3. The computer program product of claim 1 wherein the gas is expelled from a shield line.

4. The computer program product of claim 3 wherein the gas comprises air.

5. The computer program product of claim 1 wherein the back pressure is monitored by a pressure sensor on a plasma gas supply line.

6. The computer program product of claim 1 wherein the set of back pressure values and the set of coordinates are used to identify a plurality of edges.

7. The computer program product of claim 6 wherein the plurality of edges of the workpiece and a scrap clearance are used to determine a working area of the workpiece.

8. The computer program product of claim 7 wherein the scrap clearance is less than or equal to 2 inches.

9. A computer-implemented method for finding an edge of a workpiece with an automated cutting system, comprising:
providing a computing device with trace data for a test path to be traced over the workpiece;
flowing a gas from a torch of the automated cutting system;
controlling the torch in accordance with the trace data to trace the test path over the workpiece;
wherein the controlling includes measuring a back pressure of the flowing gas during the tracing;

converting the measured back pressure into a set of back pressure values;
mapping the set of back pressure values to a set of coordinates; and
analyzing the set of back pressure values and the set of coordinates to obtain a subset of coordinates representing an edge of the workpiece.

10. The method of claim 9 wherein the gas comprises air.

11. The method of claim 9 wherein the gas is expelled from a shield line.

12. The method of claim 11 wherein the gas comprises air.

13. The method of claim 9 wherein the back pressure is measured by a pressure sensor on a plasma gas supply line.

14. The method of claim 9 wherein the computing device comprises a deterministic network.

15. The method of claim 14 wherein the deterministic network comprises an EtherCAT interface.

16. The method of claim 9 wherein the set of back pressure values and the set of coordinates are used to identify a plurality of edges.

17. The method of claim 16 further comprising defining a working area of the workpiece with reference to the plurality of edges and a scrap clearance.

18. The method of claim 17 wherein the scrap clearance is less than or equal to 2 inches.

Assignees

• Hypertherm Inc

Inventors

• Peters John
• Adams Richard

Classifications

• B23K10/006 Primary

  Control circuits therefor · CPC title

• B23K10/00

  Welding or cutting by means of a plasma · CPC title