IP Library Granted Patent US 8,761,920
Granted Patent B2
US 8,761,920 · App. 13/048,992 · Granted Jun 24, 2014

Automatic probing, compensation, and adjustment of a flexible fixture for a CNC machine

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Quick Facts
Patent No.
US 8,761,920
App. No.
13/048,992
Granted
Jun 24, 2014
Kind
B2
Abstract

A method for properly locating a flexible fixture on a CNC machine comprises probing a plurality of locators on a flexible fixture to determine a locator position on a coordinate system for the CNC machine. The position for each of the plurality of locators is analyzed to determine if all of the plurality of locators are within a predetermined offset limit from a nominal position. A controller is programmed with an offset compensation amount based upon the probed position for each locator when each of the plurality of locators is within the predetermined offset limit. The locator positions are adjusted if one of the probed locations is not within the predetermined offset limit. The CNC probing programs are generated by a computer language to accommodate various fixture configurations.

Claims (22)

1. A method for properly locating a flexible fixture to a CNC machine comprising: mounting a flexible fixture on a table of the CNC machine; probing a plurality of locators on the flexible fixture to determine a locator position on a coordinate system for the CNC machine for each of the locators;

determining if each of the plurality of locators is within a predetermined offset limit from a nominal position;

programming a controller with an offset compensation amount based upon the determined locator position for each locator when all of the plurality of locators are within the predetermined offset limit;

adjusting the position of at least one of the plurality of locators to adjust a position of the flexible fixture when the determined locator position for any of the plurality of locators is not within the predetermined offset limit; and

wherein adjusting the position of at least one of the plurality of locators further comprises one of shimming the at least one of the plurality of locators, grinding the at least one of the plurality of locators and adjusting a spacer associated with the at least one of the plurality of locators.

2. The method of claim 1 , wherein adjusting at least one of the plurality of locators to adjust a position of the flexible fixture further comprises calculating an amount that the at least one of the plurality of locators must be adjusted in each direction with the controller, based upon the determined locator position for the at least one of the plurality of locators.

3. The method of claim 1 , wherein adjusting at least one of the plurality of spacers to adjust a position of the flexible fixture further comprises adjusting a spacer to reposition one of: a primary locator relative to one of a first and second axes, a secondary locator relative to one of a first and second axes, and a tertiary locator relative to a third axes of the coordinate system.

4. The method of claim 1 , wherein probing a plurality of locators on the flexible fixture to determine a locator position for each of the locators further comprises using the determined locator positions to determine a normal vector for a plane passing through three tertiary locators disposed on the flexible fixture.

5. The method of claim 1 , wherein probing a plurality of locators on the flexible fixture to determine a locator position for each of the locators further comprises measuring at least a primary locator, a secondary locator and three tertiary locators.

6. The method of claim 5 , wherein probing the primary and the secondary locators provides a xz-position for the primary and secondary locators when the flexible fixture is a horizontally mounted fixture, and probing the tertiary locators provides a y-position for each tertiary locator when the flexible fixture is a horizontally mounted fixture.

7. The method of claim 5 , wherein probing the primary and the secondary locators provides a xy-position for the primary and secondary locators when the flexible fixture is a vertically mounted fixture, and probing the tertiary locators provides z-positions for each tertiary locator when the flexible fixture is a vertically mounted fixture.

8. A method for properly locating a flexible fixture to a CNC machine comprising:

probing a primary locator, a secondary locator and at least three tertiary locators on a flexible fixture mounted to the CNC machine to determine a locator position on a coordinate system for the CNC machine for each of the locators;

determining if each of the primary locator, the secondary locator and the at least three tertiary locators is within a predetermined offset limit from a nominal position;

programming a controller with an offset compensation amount based upon the probed position for each of the primary locator, the secondary locator and the at least three tertiary locators when all of the primary locator, the secondary locator and the at least three tertiary locators are within the predetermined offset limit; and

adjusting the position of at least one of the primary locator, the secondary locator and the at least three tertiary locators to adjust a position of the flexible fixture when the determined locator position for any of the primary locator, the secondary locator and the at least three tertiary locators is not within the predetermined offset limit,

wherein adjusting the position of at least one of the primary locator, the secondary locator and the at least three tertiary locators further comprises one of shimming, grinding, and adjusting a spacer.

9. The method of claim 8 , wherein adjusting at least one of the plurality of spacers to adjust a position of the flexible fixture further comprises adjusting the spacer to move one of: the primary locator relative to one of a first and second axes, the secondary locator relative to one of a first and second axes, and any of the at least three tertiary locators relative to a third axes of the coordinate system.

10. The method of claim 8 , wherein adjusting at least one of the plurality of locators to adjust a position of the flexible fixture further comprises calculating an amount that the at least one of the plurality of locators must be adjusted in each direction with the controller, based upon the determined locator position for the respective one of the plurality of locators.

11. The method of claim 8 , wherein probing a plurality of locators on the flexible fixture to determine a locator position for each of the locators further comprises using the determined locator positions to determine a normal vector for a plane passing through the at least three tertiary locators.

12. The method of claim 8 , wherein probing the primary and the secondary locators provides a XZ-position for the primary and secondary locators when the flexible fixture is a horizontally mounted fixture, and probing the at least three tertiary locators provides a y-position for each of the at least three tertiary locators when the flexible fixture is a horizontally mounted fixture.

13. The method of claim 8 , wherein probing the primary and the secondary locators provides a XY-position for the primary and secondary locators when the flexible fixture is a vertically mounted fixture, and probing the at least three tertiary locators provides a z-position for each of the at least three tertiary locators when the flexible fixture is a vertically mounted fixture.

Assignments (3)
RELEASE OF SECURITY INTEREST Recorded Nov 7, 2014
From: WILMINGTON TRUST COMPANY
To: GM GLOBAL TECHNOLOGY OPERATIONS LLC
Reel/Frame 034287/0159 →
SECURITY AGREEMENT Recorded Jun 28, 2012
From: GM GLOBAL TECHNOLOGY OPERATIONS LLC
To: WILMINGTON TRUST COMPANY
Reel/Frame 028466/0870 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 16, 2011
From: GU, JIE; DEEDS, PAULA J.; KURGIN, SHERI K.; AGAPIOU, JOHN S.; OWEN, MICHAEL J.
To: GM GLOBAL TECHNOLOGY OPERATIONS LLC
Reel/Frame 025969/0007 →