Method and machine for determining a shape contour on a measurement object

Patent metadata

Field	Value
Publication number	US-10060737-B2
Application number	US-201514872289-A
Country	US
Kind code	B2
Filing date	Oct 1, 2015
Priority date	Apr 2, 2013
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A coordinate measuring machine has a rotary table supporting a measurement object, a measuring head including a measuring element and a frame, on which the measuring head is arranged. The frame has first, second and third frame parts moveable relative to the workpiece holder along first, second and third movement axes, respectively. The measuring element is mounted via at least one fluid bearing, such as an air bearing, on one or more of the frame parts. The measuring head is positioned at a defined position along the first, second and third movement axes. Thereafter, the at least one fluid bearing is deactivated and the rotary table rotated around a further axis while the measuring head, using the measuring element, records current measured values. A shape contour of the object is determined on the basis of the measured values recorded while the at least one fluid bearing was selectively deactivated.

First claim

What is claimed is:

1. A method for determining a shape contour on a measurement object, comprising the steps:
providing a coordinate measuring machine having a rotary table, a measuring head with a measuring element and a frame on which the measuring head is arranged,
wherein the frame has a first frame part moveable relative to the rotary table along a first movement axis, a second frame part moveable relative to the rotary table along a second movement axis, and a third frame part moveable relative to the rotary table along a third movement axis, and wherein the rotary table can be rotated about a further axis,
arranging the measurement object on the rotary table and positioning the measuring element at a defined position along the first, second and third movement axes by moving at least one of the first, second and third frame parts,
rotating the rotary table while the measuring head, using the measuring element, records current measured values which represent spatial positions of measuring points on the measurement object relative to the measuring head, and
determining the shape contour on the basis of the current measured values,
wherein the measuring element is mounted via at least one fluid bearing in order to permit a movement of the measuring element relative to the rotary table, and
wherein the at least one fluid bearing is deactivated while the current measured values are recorded.

2. The method of claim 1 , wherein the first and the second movement axes span a plane which is perpendicular to the further axis, wherein the first frame part is mounted via at least one first fluid bearing, wherein the second frame part is mounted via at least one second fluid bearing, and wherein both the at least one first and the at least one second fluid bearing are deactivated while the current measured values are recorded.

3. The method of claim 1 , wherein the first and the second movement axes span a plane which is perpendicular to the further axis, wherein the first frame part is mounted via at least one first fluid bearing, wherein the second frame part is mounted via at least one second fluid bearing, and wherein the at least one first fluid bearing is deactivated during recording of the current measured values, while the at least one second fluid bearing remains activated during recording of the current measured values.

4. The method of claim 1 , wherein the third movement axis extends parallel to the further axis, wherein the third frame part is mounted via at least one third fluid bearing, and wherein the at least one third fluid bearing is deactivated while the current measured values are recorded.

5. The method of claim 1 , wherein the third movement axis extends parallel to the further axis, wherein the third frame part is mounted via at least one third fluid bearing, and wherein the at least one third fluid bearing remains activated while the current measured values are recorded.

6. The method of claim 1 , wherein the coordinate measuring machine has a first position controller, which controls a position of the measuring head relative to the rotary table along the first movement axis, and wherein the first position controller is deactivated while the current measured values are recorded.

7. The method of claim 1 , wherein the rotary table is mounted via at least one further fluid bearing, and wherein the at least one further fluid bearing remains activated while the current measured values are recorded.

8. The method of claim 1 , wherein the measuring head has a stylus for touching the measurement object and has at least one measuring force generator, which is configured to create a defined desired measuring force on the measuring object by means of the stylus.

9. The method of claim 1 , wherein the measuring head has a working range which defines a minimum desired measuring force and a maximum desired measuring force, wherein the measured values are recorded with a defined desired measuring force which amounts to at least 30% of the maximum desired measuring force.

10. The method of claim 1 , wherein first measured values which represent a position of the measurement object along the first, second and third movement axes are recorded before the at least one fluid bearing is deactivated, and wherein the measuring head is positioned at the defined position on the basis of the first measured values.

11. The method of claim 1 , wherein calibration data are provided, said calibration data representing a position change of the measuring head as a result of deactivation of the at least one fluid bearing, and wherein said calibration data are used in the step of determining the shape contour.

12. The method of claim 1 , further comprising a step of mechanically clamping the measuring element after and in addition to the step of deactivating the at least one fluid bearing.

13. The method of claim 1 , wherein the at least one fluid bearing is an air bearing.

14. A coordinate measuring machine for determining dimensional characteristics including a shape contour on a measurement object, comprising:
a workpiece holder having a rotary table,
a measuring head having a measuring element,
a frame on which the measuring head is arranged, and
an evaluation and control unit,
wherein the frame has a first frame part which can be moved relative to the workpiece holder along a first movement axis, and
wherein the frame has a second frame part which can be moved relative to the workpiece holder along a second movement axis,
wherein the rotary table can be rotated about a further axis,
wherein the evaluation and control unit is configured to position the measuring head at a defined position along the first and second movement axes and to rotate the rotary table while the measuring head, using the measuring element, records current measured values which represent spatial positions of measuring points on the measurement object relative to the measuring head,
wherein the evaluation and control unit is further configured to determine the shape contour on the basis of the current measured values,
wherein the measuring element is mounted via at least one fluid bearing in order to permit a movement of the measuring element relative to the workpiece holder, and
wherein the evaluation and control unit is further configured to deactivate the at least one fluid bearing during recording of the current measured values.

15. The coordinate measuring machine of claim 14 , wherein the at least one fluid bearing is an air bearing.

16. A method for determining a shape contour on a measurement object, comprising the steps of:
providing a coordinate measuring machine having a rotary table, a measuring head and a frame supporting the measuring head, the frame having a first frame part moveable relative to the rotary table along a first movement axis, a second frame part moveable relative to the rotary table along a second movement axis, and a number of air bearings enabling movement of said first and second frame parts relative to the rotary table,
arranging the measurement object on the rotary table,
positioning the measurement head relative to the rotary table along said first and second movement axes,
rotating the rotary table about a further axis and simultaneously recording current measured values using the measurement head, said current measured values representing spatial positions of measuring points on the measurement object, and
determining the shape contour on the basis of the current measured values,
wherein at least one air bearing from the number of air bearings is deactivated while the current measur

Assignees

• Zeiss Carl Industrielle Messtechnik Gmbh

Inventors

• Bernhardt Ralf
• Sagemueller Rainer
• Seitz Dominik

Classifications

• G01B5/008 Primary

  using coordinate measuring machines · CPC title

• G01B21/04 Primary

  by measuring coordinates of points · CPC title