System and method for temperature compensation of measurement machine

Patent metadata

Field	Value
Publication number	US-9702681-B2
Application number	US-201313802901-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Apr 28, 2012
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

A computing device connects with a measurement machine. The measurement machine includes a raster ruler and a measurement unit. The computing device reads environmental temperatures from a temperature sensor. Compensation coefficients of the standard workpiece and compensation coefficients of the raster ruler are calculated. The computing device calculates total compensation coefficients of the standard workpiece and the raster ruler. When the measurement machine measures an object workpiece, the computing device calculates a total error of the object workpiece according to the total compensation coefficients of the standard workpiece and the total compensation coefficients of the raster ruler. Coordinates of the object workpiece are calculated according to the total error and mechanism coordinates of each axis of the measurement machine.

First claim

What is claimed is:

1. A computing device, comprising:
a storage system;
at least one processor; and
one or more programs stored in the storage system and executed by the at least one processor, the one or more programs comprising:
a first reading module reading an environmental temperature, a temperature of a standard workpiece, and a temperature of a raster ruler of a measurement machine connected to the computing device, calculating a first difference between the temperature of the standard workpiece and the environmental temperature, calculating a second difference between the temperature of the raster ruler and the environmental temperature, and detecting whether the first difference and the second difference being in an allowable error range;
a recording module recording the temperatures of the standard workpiece and the raster ruler when the first difference and the second difference being in the allowable error range;
a controlling module controlling a measurement unit of the computing device to measure a length of the standard workpiece and a scale value of the raster ruler;
wherein the controlling module further calculates a first offset value of the standard workpiece according to the length and a predetermined length of the standard workpiece, and calculates a second offset value of the raster ruler according to the scale value and a predetermined scale value of the raster ruler;
a first detecting module calculating compensation coefficients of the standard workpiece and compensation coefficients of the raster ruler according to the first offset value, the second offset value, a first measuring time for measuring the standard workpiece, a second time for measuring the raster ruler, and coordinates of each axis of the measurement machine;
a second detecting module calculating total compensation coefficients of the standard workpiece and the raster ruler according to the compensation coefficients of the standard workpiece and the raster ruler, and a number of environmental temperatures under which the standard workpiece and the raster ruler being measured;
a second reading module calculating a total error of an object workpiece according to a temperature of the object workpiece, a current temperature of the raster ruler, a current environmental temperature, the total compensation coefficients of the standard workpiece, and the total compensation coefficients of the raster ruler; and
a compensating module calculating coordinates of the object workpiece according to the total error and coordinates of the measurement machine.

2. The computing device as described in claim 1 , wherein the one or more programs further comprises: a first counting module increasing the first measuring time when the measurement unit measuring the length of the standard workpiece, and increasing the second measuring time when the measurement unit measuring the scale value of the raster ruler.

3. The computing device as described in claim 1 , wherein the one or more programs further comprises: a second counting module increasing the number of the environmental temperature.

4. A method being executed by a processor of a computing device for temperature compensation of a measurement machine, comprising:
reading an environmental temperature, a temperature of a standard workpiece, and a temperature of a raster ruler of a measurement machine;
calculating a first difference between the temperature of the standard workpiece and the environmental temperature, and a second difference between the temperature of the raster ruler and the environmental temperature;
detecting whether the first difference and the second difference being in an allowable error range;
recording the temperatures of the standard workpiece and the raster when the first difference and the second difference being in the allowable error range;
controlling a measurement unit of the computing device to measure a length of a standard workpiece and a scale value of a raster ruler of the measurement machine;
calculating a first offset value of the standard workpiece according to the length and a predetermined length of the standard workpiece, and calculating a second offset value of the raster ruler according to the scale value and a predetermined scale value of the raster ruler,
calculating compensation coefficients of the standard workpiece and compensation coefficients of the raster ruler according to the first offset value, the second offset value, a first measuring time for measuring the standard workpiece, a second time for measuring the raster ruler, and coordinates of each axis of the measurement machine;
calculating total compensation coefficients of the standard workpiece and the raster ruler according to the compensation coefficients of the standard workpiece and the raster ruler, and a number of environmental temperatures that the standard workpiece and the raster ruler being measured;
calculating a total error of an object workpiece according to a temperature of the object workpiece, a current temperature of the raster ruler, a current environmental temperature, the total compensation coefficients of the standard workpiece, and the total compensation coefficients of the raster ruler; and
calculating coordinates of the object workpiece according to the total error and coordinates of the measurement machine of each axis.

5. The method as described in claim 4 , further comprising:
increasing the first measuring time when the measurement unit measures the length of the standard workpiece; and
increasing the second measuring time when the measurement unit measures the scale value of the raster ruler.

6. The method as described in claim 4 , further comprising:
increasing the number of the environmental temperature.

7. A non-transitory storage medium having stored thereon instructions that, when executed by a processor, causes the processor to perform a method for temperature compensation of a measurement machine, the method comprising:
reading an environmental temperature, a temperature of a standard workpiece and a temperature of a raster ruler of a measurement machine;
calculating a first difference between the temperature of the standard workpiece and the environmental temperature, and a second difference between the temperature of the raster ruler and the environmental temperature;
detecting whether the first difference and the second difference being in an allowable error range;
recording the temperatures of the standard workpiece and the raster when the first difference and the second difference being in the allowable error range;
controlling a measurement unit of the computing device to measure a length of a standard workpiece and a scale value of a raster ruler of the measurement machine;
calculating a first offset value of the standard workpiece according to the length and a predetermined length of the standard workpiece, and calculating a second offset value of the raster ruler according to the scale value and a predetermined scale value of the raster ruler,
calculating compensation coefficients of the standard workpiece and compensation coefficients of the raster ruler according to the first offset value, the second offset value, a first measuring time for measuring the standard workpiece, a second time for measuring the raster ruler, and coordinates of each axis of the measurement machine;
calculating total compensation coefficients of the standard workpiece and the raster ruler according to the compensation coefficients of the standard workpiece and the raster ruler, and a number of environmental temperatures that the standard workpiece and the raster ruler being measured;
calculating a total error of an object workpiece according to a temperature of the object workpiece, a temperature of

Assignees

• Hong Fu Jin Prec Ind (Shenzhen) Co Ltd
• Hon Hai Prec Ind Co Ltd

Inventors

• Chang Chih-Kuang
• Yang Hua-Wei

Classifications

• G01B5/0014 Primary

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

• G01B21/045

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

• B23Q11/0003

  Arrangements for preventing undesired thermal effects on tools or parts of the machine (B23Q11/10, B23Q11/12 and B23Q11/14 take precedence) · CPC title

• G05B2219/37193

  Multicoordinate measuring system, machine, cmm · CPC title

• G01B11/03

  by measuring coordinates of points · CPC title