Method for correcting an angular deviation in the operation of a coordinate measuring machine

Patent metadata

Field	Value
Publication number	US-10466029-B2
Application number	US-201414773457-A
Country	US
Kind code	B2
Filing date	Mar 13, 2014
Priority date	Mar 15, 2013
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A method for correcting an angular deviation between a real angle and an ideal angle between motion axes of a coordinate measuring device. The angular deviation depends on position, temperature, and/or loading mass. Values of a position-dependent angular deviation for partial measurement ranges of the coordinate measuring device are determined, and/or a difference between the angular deviation in a partial measurement range and a total measurement range, and the position-dependent angular deviation is corrected by using these values. Values of the temperature-dependent angular deviation for at least two different temperatures are determined and the deviation is corrected based on these. Values of the loading-mass-dependent angular deviation for loading the coordinate measuring device with at least two different loading masses are determined in a range of loading masses and/or information is obtained for correcting the loading-mass-dependent angular deviation in a temperature range and the deviation is corrected by using one of the values or information.

First claim

The invention claimed is:

1. A method for improving accuracy in measuring coordinates of a workpiece in a coordinate measuring machine, the method comprising correcting an angular deviation of a real angle from an ideal angle between movement axes of the coordinate measuring machine, wherein the angular deviation is dependent on a location, the method comprising the following steps:
a-1) determining values of a location-dependent angular deviation by carrying out one or both of the following:
i) in each case determining at least one value for at least two partial measurement regions of the coordinate measuring machine which form only part of a total measurement region of the coordinate measuring machine, wherein values of the location-dependent angular deviation determined for different partial measurement regions of the coordinate measuring machine differ or may differ; and/or
ii) determining at least one value for at least one partial measurement region and determining at least one value of the angular deviation for a total measurement region of the coordinate measuring machine, wherein the at least one determined value for a partial measurement region of the coordinate measuring machine differs or may differ from the at least one value for the total measurement region,
a-1a) measuring coordinates of the workpiece with a measuring head or sensor of the coordinate measuring machine, the coordinate measuring machine including a controller configured to determine or to receive notification from a computer whether a measurement region lies in one of the partial measurement regions for which at least one value of the angular deviation was determined, the method further including determining, by the controller, whether a current position of the measuring head or sensor is situated in the one of the partial measurement regions;

b-1) correcting the location-dependent angular deviation in the one of the partial measurement regions of the coordinate measuring machine for which at least one value of the location-dependent angular deviation was determined, using the at least one determined value from step a-1), the correction being done by the controller and/or the computer during or after the movement of the measuring head or sensor, with values of the positions of the measuring head or sensor being corrected depending on the location;
b-1a) obtaining corrected measurement results from the coordinate measurement of the workpiece.

2. The method of claim 1 , wherein the angular deviation is further dependent on at least one of a temperature or a loading mass, the method further comprising the steps of:
a-2) determining values of a temperature-dependent angular deviation for at least two different temperatures by determining values of the temperature-dependent angular deviation in a temperature range and/or obtaining information for correcting the temperature-dependent angular deviation in a temperature range;
a-2a) measuring coordinates of the workpiece with a measuring head or sensor of the coordinate measuring machine, and determining the temperature;
b-2) correcting the temperature-dependent angular deviation using one of the determined values and/or the obtained information from step a-2) with the controller and/or the computer during or after the movement of the measuring head or sensor, with values of the positions of the measuring head or sensor being corrected depending on the temperature;
and/or the steps of:
a-3) determining one value or a plurality of values of a loading mass-dependent angular deviation upon the loading of the coordinate measuring machine with one loading mass or with at least two different loading masses by determining a value for the loading mass-dependent angular deviation or values of the loading mass-dependent angular deviation in a range of loading masses and/or obtaining information for correcting the loading mass-dependent angular deviation;
a-3a) measuring coordinates of the workpiece with a measuring head or sensor of the coordinate measuring machine and determining the loading mass;
b-3) correcting the loading mass-dependent angular deviation using one of the determined values and/or the obtained information from step a-3) with the controller and/or the computer during or after the movement of the measuring head or sensor, with values of the positions of the measuring head or sensor being corrected depending on the loading mass.

3. The method according to claim 1 , wherein at least one of the partial measurement regions is a continuous linear region, a continuous planar region or a continuous volume region.

4. The method according to claim 1 , which comprises:
taking into account the angular deviation in a partial measurement region together with a rotational guidance deviation of a real movement of parts of the coordinate measuring machine along a movement axis from an ideal movement of the parts of the coordinate measuring machine along the movement axis by forming a correction function for correcting the angular deviation and the axis deviation; and
using values of the angular deviation in the at least one partial measurement region and values of the rotational guidance deviation for forming the correction function.

5. The method according to claim 1 , wherein the step of correcting the location-dependent angular deviation in the at least one partial measurement region comprises determining a difference between the at least one value of the angular deviation for the total measurement region and the at least one value of the angular deviation for the partial measurement region, and using the difference when correcting the angular deviation.

6. The method according to claim 1 , wherein the step of correcting the location-dependent angular deviation comprises disregarding the at least one value of the angular deviation for the total measurement region and using the at least one value of the angular deviation in the at least one partial measurement region when correcting the angular deviation.

7. The method according to claim 1 , wherein the coordinate measuring machine has a rotary table and one of the partial measurement regions in step a-1) i) or the partial measurement region in step a-1) ii) is the measurement region above the rotary table.

8. The method according to claim 7 , which comprises loading the rotary table with a workpiece mass and carrying out a correction of the location-dependent angular deviation and a correction of the loading mass-dependent angular deviation.

9. The method according to claim 1 , which comprises defining the partial measurement region in which the at least one value of the angular deviation is determined with dimensions equal or similar to dimensions of a workpiece to be measured.

10. The method according to claim 1 , which comprises carrying out the step of determining the at least one value of the angular deviation with a test object adapted to a size of the workpiece to be measured.

11. The method according to claim 1 , which comprises carrying out the step of determining the at least one value of the angular deviation with a test object adapted to a mass and/or a position and/or an orientation of a workpiece to be measured.

12. The method according to claim 1 , which comprises storing in the coordinate measuring machine the following:
for at least two partial measurement regions of the coordinate measuring machine in each case at least one value of an angular deviation, or for at least one partial measurement region of the coordinate measuring machine and a total measurement region of the coordinate measuring machine in each case at least one value of an angular deviation; and
using the at least one valu

Assignees

• Zeiss Carl Industrielle Messtechnik Gmbh

Inventors

• Fuchs Andreas
• Held Tobias
• Sagemueller Rainer
• Seitz Dominik

Classifications

• G01B5/0016

  due to weight (on machine tools B23Q11/001) · CPC title

• G01B5/0014

  due to temperature (on machine tools B23Q11/0003) · CPC title

• G01B5/004 Primary

  for measuring coordinates of points · CPC title

• G01B21/045 Primary

  Correction of measurements (G01B9/02055 takes precedence) · CPC title