COORDINATE MEASURING MACHINE AND METHOD FOR COMPENSATING FOR LARGE WORKPIECE MASSES

• US 20170241760A1
• Filed: 05/10/2017
• Published: 08/24/2017
• Est. Priority Date: 11/25/2014
• Status: Active Grant

• Current Assignee: Carl Zeiss Industrielle Messtechnik GmbH (Carl-Zeiss-Stiftung)
• Original Assignee: Carl Zeiss Industrielle Messtechnik GmbH (Carl-Zeiss-Stiftung)
• Inventors: ROTH, Roland, LEITENBERGER, Werner, GRUPP, Guenter, JACOBS, Oliver, WUERFEL, Carsten
• Granted Patent: US 10,451,398 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 21/045 Correction of measurements G01B9/02055 takes precedence
• CPC Class Codes: G01B 5/0004 Supports G01B5/025 takes precedence
• CPC Class Codes: G01B 5/0016 due to weight on machine tools B23Q11/001
• CPC Class Codes: G01B 5/008 using coordinate measuring machines

Abstract

The present invention relates to a coordinate measuring machine with a measuring system for measuring a workpiece, a carrier structure for carrying the measuring system and a base plate for supporting the workpiece. The carrier structure is movably guided in at least one direction on the base plate. The coordinate measuring machine also has a first support system with at least three supports for supporting the base plate, a second support system and a control device for controlling the second support system dependent on a force application to the first support system. The present invention also relates to a method for compensating for large workpiece masses on a coordinate measuring machine.

Claims

1. A coordinate measuring machine, with a measuring system for measuring a workpiece, a carrier structure for carrying the measuring system and a base plate for supporting the workpiece, wherein the carrier structure is movably guided in at least one direction on the base plate, and wherein the coordinate measuring machine also has a first support system with at least three supports for supporting the base plate, wherein the coordinate measuring machine also has a second support system and a control device for controlling the second support system dependent on a force application to the first support system.

2. The coordinate measuring machine as claimed in claim 1, wherein the at least three supports of the first support system are respectively formed by a main air spring device.

3. The coordinate measuring machine as claimed in claim 2, wherein the first support system has at least three control valve arrangements for controlling the at least three main air spring devices.

4. The coordinate measuring machine as claimed in claim 3, wherein the at least three control valve arrangements are in each case a mechanical control valve arrangement

5. The coordinate measuring machine as claimed in claim 1, wherein the first support system has four main air spring devices wherein a first and a fourth main air spring device are assigned a shared first control valve arrangement, wherein a second main air spring device is assigned a second control valve arrangement, and wherein a third main air spring device is assigned a third control valve arrangement.

6. The coordinate measuring machine as claimed in claim 1, wherein the first support system has at least three force application sensors for determining a variable that represents a force applied to at least one support.

7. The coordinate measuring machine as claimed in claim 6, wherein the determined variable is an air pressure.

8. The coordinate measuring machine as claimed in claim 6, wherein each control valve arrangement of the first support system is assigned a force application sensor.

9. The coordinate measuring machine as claimed in claim 1, wherein the second support system has at least one secondary air spring device, which forms a support of the second support system.

10. The coordinate measuring machine as claimed in claim 1, wherein the second support system has at least three supports, and wherein each support is formed by a secondary air spring device.

11. The coordinate measuring machine as claimed in claim 10, wherein the second support system has at least three control valve arrangements for controlling the at least three secondary air spring devices.

12. The coordinate measuring machine as claimed in claim 11, wherein the at least three control valve arrangements are in each case an electronic control valve arrangement.

13. The coordinate measuring machine as claimed in claim 1, wherein the second support system has four secondary air spring devices, wherein a first and a fourth secondary air spring device are assigned a shared first control valve arrangement, wherein a second secondary air spring device is assigned a second control valve arrangement, and wherein a third secondary air spring device is assigned a third control valve arrangement.

14. The coordinate measuring machine as claimed in claim 1, wherein the second support system has at least four secondary air spring devices, wherein the coordinate measuring machine also has a number of control valve arrangements corresponding to the number of secondary air spring devices, and each control valve arrangement is assigned to precisely one secondary air spring device.

15. The coordinate measuring machine as claimed in claim 1, wherein a number of supports of the first support system corresponds to a number of supports of the second support system, and wherein a number of control valve arrangements of the first support system corresponds to a number of control valve arrangements of the second support system, and wherein a number of control valve arrangements of the first support system corresponds to a number of force application sensors for determining a variable that represents a force applied to at least one support of the first support system.

16. The coordinate measuring machine as claimed in claim 1, wherein the supports of the second support system are arranged between the supports of the first support system on the base plate.

17. The coordinate measuring machine as claimed in claim 1, wherein the supports of the first support system create a supporting area on the base plate, wherein the supports of the second support system are arranged within the supporting area on the base plate.

18. The coordinate measuring machine as claimed in claim 1, wherein the base plate has a geometrical center, and wherein a greatest distance of a support of the second support system from the geometrical center is less than a smallest distance of a support of the first support system from the geometrical center.

19. The coordinate measuring machine as claimed in claim 1, wherein an area enclosed by the supports of the second support system includes a geometrical center of the base plate.

20. The coordinate measuring machine as claimed in claim 19, wherein the area enclosed by the supports of the second support system corresponds to between 20% and 40% of the size of an area enclosed by the supports of the first support system.

21. The coordinate measuring machine as claimed in claim 1, wherein the carrier structure is a gantry construction.

22. The coordinate measuring machine as claimed in claim 21, wherein the gantry construction has a gantry movably guided in a first direction (Y) on the base plate, a carriage movably guided in a second direction (X), perpendicular to the first direction (Y), on the gantry and a quill movably guided in a third direction (Z), perpendicular to the first (Y) and second (X) directions, on the carriage.

23. A method for compensating for large workpiece masses on a coordinate measuring machine with a measuring system for measuring a workpiece, a carrier structure for carrying the measuring system and a base plate for supporting the workpiece, wherein the carrier structure is movably guided in at least one direction on the base plate, and wherein the coordinate measuring machine also has a first support system with at least three supports for supporting the base plate, a second support system and a control device for controlling the second support system dependent on a force application to the first support system, comprising the following steps:

calibrating a reference state of the base plate by means of the first support system,

arranging on the base plate a workpiece to be measured by means of the coordinate measuring machine,

determining variables that represent the forces applied to the at least three supports of the first support system by the workpiece, and

controlling the second support system by means of the control device in such a way that the reference state is restored.

24. The method as claimed in claim 23, wherein, before the controlling step and after the determining step, it is established that the forces applied by the workpiece to the at least three supports of the first support system lie above a predetermined threshold value.