Waterjet cutting system with standoff distance control

Patent metadata

Field	Value
Publication number	US-9003936-B2
Application number	US-201113194579-A
Country	US
Kind code	B2
Filing date	Jul 29, 2011
Priority date	Jul 29, 2011
Publication date	Apr 14, 2015
Grant date	Apr 14, 2015

Abstract

A cutting head of a waterjet cutting system is provided having an environment control device and a measurement device. The environment control device is positioned to act on a surface of a workpiece at least during a measurement operation to establish a measurement area on the surface of the workpiece substantially unobstructed by fluid. The measurement device is positioned to selectively obtain information from within the measurement area indicative of a position of the cutting head relative to the workpiece. A control system is further provided and operable to position the cutting head relative to the workpiece at a standoff distance based at least in part on the information indicative of the position of the cutting head relative to the workpiece obtained by the measurement device. A method of operating a waterjet cutting system is also provided.

First claim

The invention claimed is:

1. A cutting head of a waterjet cutting system, the cutting head comprising:
a nozzle having an orifice through which fluid passes during operation to generate a high-pressure fluid jet for processing a workpiece;
an environment control device positioned to act on a surface of the workpiece at least during a measurement operation, the environment control device configured to establish a measurement area on the surface of the workpiece via a discharged fluid stream or suction; and
a measurement device positioned relative to the environment control device to selectively obtain information from within the measurement area with a laser beam dischargeable by the measurement device to impinge on the workpiece, the obtained information being indicative of a position of a tip of the nozzle of the cutting head relative to the workpiece.

2. The cutting head of claim 1 , further comprising:
a wrist manipulable in space to position and orient the nozzle relative to the workpiece, and wherein the environment control device and the measurement device are positioned on the wrist to move in unison with the nozzle.

3. The cutting head of claim 2 wherein an axis of the nozzle and a rotational axis of the wrist define a reference plane, and wherein the measurement device is positioned to selectively obtain information in a location offset from the reference plane.

4. The cutting head of claim 1 wherein the environment control device is configured to selectively generate an air stream, a centerline of the air stream oriented to intersect a path of the laser beam at a position below the surface of the workpiece.

5. The cutting head of claim 1 wherein the environment control device is configured to selectively generate an air stream, a centerline of the air stream oriented to impinge on the surface of the workpiece within the measurement area at a position aft of a path of the laser beam and to flow across the path of the laser beam during the measurement operation.

6. The cutting head of claim 1 wherein the environment control device is configured to selectively generate an air stream such that a centerline of the air stream and a path of the laser beam define an acute angle.

7. The cutting head of claim 1 wherein the laser beam is oriented parallel to a centerline of the nozzle.

8. The cutting head of claim 1 wherein the cutting head operates within a surrounding waterjet cutting environment, and wherein the environment control device is configured to establish the measurement area on the surface of the workpiece such that the measurement area is unobstructed by fluid, vapor or particulate material of the surrounding waterj et cutting environment.

9. The cutting head of claim 1 , further comprising:
a shield to protect portions of the cutting head and surrounding components during operation, the environment control device passing through a portion of the shield.

10. The cutting head of claim 9 wherein the environment control device is configured to generate a vacuum to establish the measurement area beneath the shield by evacuating a space generally enclosed by the shield and the surface of the workpiece.

11. The cutting head of claim 9 wherein the environment control device is configured to generate an air stream to establish the measurement area beneath the shield.

12. The cutting head of claim 9 wherein the measuring device is configured to selectively generate the laser beam to pass through a void in the shield.

13. The cutting head of claim 1 , further comprising:
a shutter mechanism configured to selectively isolate an operative portion of the measurement device from a surrounding environment of the waterjet cutting system.

14. The cutting head of claim 13 wherein the shutter mechanism includes a shutter movable between an open position and a closed position, the shutter isolating the operative portion of the measurement device from the surrounding environment when in the closed position and enabling the measurement device to obtain the information indicative of the position of the tip of the nozzle of the cutting head relative to the workpiece when in the open position.

15. The cutting head of claim 14 wherein the shutter is movably coupled to a linear actuator for selectively moving the shutter between the open position and the closed position.

16. The cutting head of claim 14 wherein the shutter is a deformable member coupled to a pressure generating source for selectively transitioning the shutter between the open position and the closed position.

17. The cutting head of claim 14 wherein the shutter is positioned in a housing to selectively isolate an internal cavity of the housing from the surrounding environment, the housing including a passageway to route pressurized air into the internal cavity.

18. The cutting head of claim 17 wherein the passageway is oriented to route pressurized air into the internal cavity of the housing across a face of an operable portion of the measurement device.

19. The cutting head of claim 17 wherein the passageway is connected to another passageway configured to feed pressurized air to the environment control device, and wherein, when pressurized air is fed to the environment control device to generate an air stream, pressurized air is simultaneously fed to the internal cavity of the housing.

20. The cutting head of claim 14 wherein the shutter is positioned in a housing to selectively isolate an internal cavity of the housing from the surrounding environment, and wherein the shutter is biased toward the housing.

21. A waterjet cutting system, comprising:
a cutting head having a nozzle with an orifice through which fluid passes during operation to generate a high-pressure fluid jet for processing a workpiece;
an environment control device positioned to act on a surface of the workpiece at least during a measurement operation, the environment control device configured to establish a measurement area on the surface of the workpiece via a discharged fluid stream or suction;
a measurement device positioned to selectively obtain information from within the measurement area with a laser beam dischargeable by the measurement device to impinge on the workpiece, the obtained information being indicative of a position of a tip of the nozzle of the cutting head relative to the workpiece; and
a control system to move the cutting head relative to the workpiece, the control system operable to position the tip of the nozzle of the cutting head relative to the workpiece at a standoff distance based at least in part on the information indicative of the position of the tip of the nozzle of the cutting head obtained from the measurement device.

22. The waterjet cutting system of claim 21 wherein the control system is configured to filter out information obtained by the laser beam from target areas of the workpiece having pre-cut kerfs and to use information indicative of the tip of the nozzle of the cutting head relative to the workpiece only from uncut target areas of the workpiece when calculating the standoff distance.

23. The waterjet cutting system of claim 21 wherein the cutting head operates within a surrounding waterjet cutting environment, and wherein the environment control device is configured to establish the measurement area on the surface of the workpiece such that the measurement area is unobstructed by fluid, vapor or particulate material of the surrounding waterjet cutting environment.

Assignees

• Chillman Alex M
• Eide Kirby J
• Schuman Bruce M
• Tanuma Aki
• Vaughan Sean A
• Chenoweth Ii Raymond L
• Hageman Iii Richard B
• Craigen Steven J
• Hashish Mohamed A
• Burnham Charles D
• Flow Int Corp

Inventors

• Chillman Alex M
• Eide Kirby J
• Schuman Bruce M
• Tanuma Aki
• Vaughan Sean A
• Chenoweth Ii Raymond L
• Hageman Iii Richard B
• Craigen Steven J
• Hashish Mohamed A
• Burnham Charles D

Classifications

• B24C5/00

  Devices or accessories for generating abrasive blasts · CPC title

• B26F3/004

  by means of a fluid jet (methods for use of abrasive blasting for cutting B24C1/045; guns for abrasive fluid jets B24C5/02; perforating by non-mechanical means, e.g. by fluid jet B26F1/26) · CPC title

• B26D5/00

  Arrangements for operating and controlling machines or devices for cutting, cutting-out, stamping-out, punching, perforating, or severing by means other than cutting · CPC title

• B24C9/00

  Appurtenances of abrasive blasting machines or devices, e.g. working chambers, arrangements for handling used abrasive material · CPC title

• B24C5/02

  Blast guns, e.g. for generating high velocity abrasive fluid jets for cutting materials {(perforating by fluid jet B26F1/26)} · CPC title