Position measurement method of object in machine tool and position measurement system of the same

Patent metadata

Field	Value
Publication number	US-10359266-B2
Application number	US-201715481548-A
Country	US
Kind code	B2
Filing date	Apr 7, 2017
Priority date	Apr 19, 2016
Publication date	Jul 23, 2019
Grant date	Jul 23, 2019

Abstract

A position measurement method to measure a position of an object in a machine tool includes a tool sensor position acquisition stage, a reference block position acquisition stage, a relative position calculation stage, a reference tool position acquisition stage, a position measurement sensor measurement stage, a length compensation value calculation stage, and a position measurement stage. In the position measurement stage, the measurement position of the object is compensated using a length direction compensation value of a position measurement sensor calculated in the length compensation value calculation stage. The object is measured by the position measurement sensor installed to a main spindle.

First claim

What is claimed is:

1. A position measurement method of object in machine tool for measuring a position of the object secured on a table by a position measurement sensor using the machine tool, the machine tool including three or more translational axes, a rotatable main spindle to which a tool is to be installed, and the table, the position measurement sensor being installable to the main spindle, the position measurement method comprising:
a tool sensor position acquisition stage of installing a reference tool for a length reference of the tool to the main spindle and acquiring a sensing position of a distal end of the reference tool using a tool sensor;
a reference block position acquisition stage of acquiring positions of the translational axes when the reference tool installed to the main spindle is directly or indirectly brought into contact with a reference block disposed at the tool sensor side;
a relative position calculation stage of calculating a relative position of the reference block with respect to the sensing position from the sensing position acquired in the tool sensor position acquisition stage and the positions of the translational axes acquired in the reference block position acquisition stage;
a reference tool position acquisition stage of installing the reference tool to the main spindle and acquiring a reference tool position using the tool sensor, the reference tool position being a distal end position of the reference tool;
a position measurement sensor measurement stage of installing the position measurement sensor to the main spindle and measuring a position of the reference block using the position measurement sensor;
a length compensation value calculation stage of calculating a length direction compensation value of the position measurement sensor from the reference tool position acquired in the reference tool position acquisition stage, the position of the reference block measured in the position measurement sensor measurement stage, the relative position calculated in the relative position calculation stage, and the length of the reference tool; and
a position measurement stage of compensating the measurement position of the object using the length direction compensation value of the position measurement sensor calculated in the length compensation value calculation stage, the object being measured by the position measurement sensor installed to the main spindle.

2. The position measurement method of object in machine tool according to claim 1 , wherein
the tool sensor position acquisition stage to the relative position calculation stage are configured to be executed once, the reference tool position acquisition stage to the position measurement stage being configured to be executed several times.

3. The position measurement method of object in machine tool according to claim 1 , wherein
in the position measurement sensor measurement stage and the position measurement stage, the positions measured by the position measurement sensor are positions of the translational axes when the position measurement sensor senses a contact with the object.

4. The position measurement method of object in machine tool according to claim 1 , further comprising
a diameter compensation value acquisition stage of acquiring a radial direction compensation value of the position measurement sensor as a contact type sensor to the object, the diameter compensation value acquisition stage being performed before the execution of the position measurement stage, wherein
the position measurement stage includes compensating the measurement position of the object also using the diameter compensation value acquired in the diameter compensation value acquisition stage.

5. A position measurement system of object in machine tool for measuring a position of the object secured on a table by a position measurement sensor in the machine tool, the machine tool including three or more translational axes, a rotatable main spindle to which a tool is to be installed, the table, the position measurement sensor installable to the main spindle, and a control device configured to control the translational axes and the main spindle, the position measurement system comprising:
a reference tool for a length reference of the tool;
a tool sensor configured to detect a distal end position of the reference tool installed to the main spindle;
a reference block installed to the tool sensor side;
a tool sensor position acquisition unit configured to move the reference tool installed to the main spindle in the translational axes, the tool sensor position acquisition unit being configured to acquire and store a sensing position of the distal end of the reference tool using the tool sensor;
a reference block position acquisition unit configured to move the reference tool installed to the main spindle in the translational axes to directly or indirectly bring the reference tool into contact with the reference block, the reference block position acquisition unit being configured to acquire and store positions of the translational axes at the contact;
a relative position calculation unit configured to calculate and store a relative position of the reference block with respect to the sensing position from the sensing position acquired in the tool sensor position acquisition unit and the positions of the translational axes acquired in the reference block position acquisition unit;
a reference tool position acquisition unit configured to move the reference tool installed to the main spindle in the translational axes, the reference tool position acquisition unit being configured to acquire and store a reference tool position with the tool sensor, the reference tool position being the distal end position of the reference tool;
a measurement position acquisition unit configured to measure and store a position of the reference block with the position measurement sensor installed to the main spindle;
a length compensation value calculation unit configured to calculate and store a length direction compensation value of the position measurement sensor from the reference tool position acquired in the reference tool position acquisition unit, the position of the reference block acquired in the measurement position acquisition unit, the relative position acquired in the relative position calculation unit, and the length of the reference tool; and
a position calculation unit configured to compensate the measurement position of the position measurement sensor using the length compensation value stored in the length compensation value calculation unit and calculate the position of the object.

6. The position measurement system of object in machine tool according to claim 5 , wherein
the position measurement sensor is configured to measure the positions of the translational axes when the position measurement sensor senses the object with or without considering a signal delay.

7. The position measurement system of object in machine tool according to claim 5 , further comprising
a diameter compensation value acquisition unit configured to acquire and store a radial direction compensation value of the position measurement sensor as a contact type sensor to the object, wherein
the position calculation unit is configured to compensate the measurement position of the position measurement sensor using the length compensation value acquired in the length compensation value calculation unit and the diameter compensation value acquired in the diameter compensation value acquisition unit and calculate the position of the object.

8. A position measurement method of object in machine tool for measuring a position of the object secured on a table by a position measurement sensor using the machine tool,

Assignees

• Okuma Machinery Works Ltd

Inventors

• Kanbe Reiji
• Matsushita Tetsuya

Classifications

• G01B5/008

  using coordinate measuring machines · CPC title

• G01B5/016 Primary

  Constructional details of contacts · CPC title

• B23Q17/22 Primary

  for indicating or measuring existing or desired position of tool or work {(B23Q16/005 takes precedence)} · CPC title

• B23Q17/2461

  Length · CPC title

• B23Q17/0923

  Tool length · CPC title