Form measuring machine and form measuring method

Patent metadata

Field	Value
Publication number	US-9719779-B2
Application number	US-201514929588-A
Country	US
Kind code	B2
Filing date	Nov 2, 2015
Priority date	Nov 6, 2014
Publication date	Aug 1, 2017
Grant date	Aug 1, 2017

Abstract

A form measuring machine includes: a scanning probe including a stylus with a tip ball and a probe body attached with the stylus; a movable slider supporting the scanning probe; a scale detecting a slider displacement of the slider; a tip ball displacement detector detecting a tip ball displacement of the tip ball; and an arithmetic unit calculating a measurement value based on the slider displacement, the tip ball displacement and a correction filter and comprising a correction filter setting section that: calculates a correction matrix diagonal component from the slider displacement and the tip ball displacement detected by calibration of the scanning probe; and calculates a correction factor of the correction filter from the correction matrix diagonal component to set the correction filter.

First claim

What is claimed is:

1. A form measuring machine comprising:
a scanning probe comprising: a stylus with a tip end provided with a tip ball that is brought into contact with an object to be measured; and a probe body attached with the stylus;
a movable slider configured to support the scanning probe;
a scale configured to detect a slider displacement of the slider;
a tip ball displacement detector configured to detect a tip ball displacement of the tip ball of the scanning probe relative to a support portion where the slider supports the scanning probe; and
an arithmetic unit configured to calculate a measurement value based on the slider displacement detected by the scale, the tip ball displacement detected by the tip ball displacement detector, and a correction filter configured to correct a measurement error, the arithmetic unit comprising a correction filter setting section configured to: calculate a correction matrix diagonal component from the slider displacement detected by the scale and the tip ball displacement detected by the tip ball displacement detector during measurement of a calibration reference piece; and calculate a correction factor of the correction filter from the correction matrix diagonal component to set the correction filter, the correction matrix associating the tip ball displacement with a coordinate system for the scale.

2. The form measuring machine according to claim 1 , wherein the correction filter setting section calculates the correction factor of the correction filter using a factor calculation function or table data that shows a relationship between the correction matrix diagonal component for the scanning probe and the correction factor of the correction filter for the scanning probe.

3. The form measuring machine according to claim 2 , wherein
the stylus comprises plural types of styli attached in turn to the probe body to define a plurality of scanning probes comprising the scanning probe, the scanning probes being used in turn to measure the calibration reference piece to calculate individual values of the correction matrix diagonal component and corresponding individual values of the correction factor of the correction filter for the scanning probes, and
the arithmetic unit further comprises a function generating section configured to generate the factor calculation function or the table data based on the individual values of the correction matrix diagonal component and the corresponding individual values of the correction factor of the correction filter for the scanning probes.

4. The form measuring machine according to claim 1 , wherein
the correction factor of the correction filter comprises a zero-point angular frequency, a pole angular frequency, a zero-point damping factor and a pole damping factor, and
the correction filter setting section calculates at least the zero-point angular frequency.

5. The form measuring machine according to claim 2 , wherein
the correction factor of the correction filter comprises a zero-point angular frequency, a pole angular frequency, a zero-point damping factor and a pole damping factor, and
the correction filter setting section calculates at least the zero-point angular frequency.

6. The form measuring machine according to claim 3 , wherein
the correction factor of the correction filter comprises a zero-point angular frequency, a pole angular frequency, a zero-point damping factor and a pole damping factor, and
the correction filter setting section calculates at least the zero-point angular frequency.

7. A form measuring method for a form measuring machine, the form measuring machine comprising:
a scanning probe comprising: a stylus with a tip end provided with a tip ball that is brought into contact with an object to be measured; and a probe body attached with the stylus;
a movable slider configured to support the scanning probe;
a scale configured to detect a slider displacement of the slider; and
a tip ball displacement detector configured to detect a tip ball displacement of the tip ball of the scanning probe relative to a support portion where the slider supports the scanning probe, the method comprising:
calculating a correction matrix diagonal component from the slider displacement detected by the scale and the tip ball displacement detected by the tip ball displacement detector during measurement of a calibration reference piece, the correction matrix associating the tip ball displacement with a coordinate system for the scale;
calculating a correction factor of the correction filter from the correction matrix diagonal component to set the correction filter; and
calculating a measurement value based on the set correction filter, the slider displacement detected by the scale, and the tip ball displacement detected by the tip ball displacement detector.

Assignees

• Mitutoyo Corp

Inventors

• Ishikawa Nobuhiro
• Nakagawa Hideyuki

Classifications

• G01B21/045 Primary

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