Method for processing workpiece in tool machine and behavior measurement device

• US 8,423,171 B2
• Filed: 10/23/2008
• Issued: 04/16/2013
• Est. Priority Date: 11/05/2007
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Heavy Industries, Ltd.
• Original Assignee: Mitsubishi Heavy Industries, Ltd.
• Inventors: Sato, Yoshikatsu, Honda, Shigeru
• Primary Examiner(s): Gaffin, Jeffrey A
• Assistant Examiner(s): LOPEZ ALVAREZ, OLVIN
• Application Number:
  US12/665,629
• Publication Number:
  US 20100145499A1
• Time in Patent Office: 1,636 Days
• Field of Search: 700/193, 352/152, 382/154, 356/493
• US Class Current: 700/193
• CPC Class Codes: B23Q 11/0003 Arrangements for preventing undesired thermal effects on tools or parts of the machine B23Q11/10, B23Q11/12 and B23Q11/14 take precedence
• CPC Class Codes: B23Q 15/20 before or after the tool acts upon the workpiece
• CPC Class Codes: B23Q 17/22 for indicating or measuring existing or desired position of tool or work B23Q16/005 takes precedence
• CPC Class Codes: G05B 19/404 characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia G05B19/19, G05B19/41 take precedence
• CPC Class Codes: G05B 2219/49219 Compensation temperature, thermal displacement

Abstract

In a method for processing a workpiece in a tool machine, a first step (Step S4) for continuously measuring a position of a tip portion of a tool attached to a main axis, a second step (Step S5) for computing a displacement amount of the position of the tip point of the tool based on a result of the measurement, a third step (Step S8) for observing a time period while the displace amount is belonged in arrange of allowable displace amount previously determined, a fourth step (Step S9) for keeping an idling operation in case that the time for which the displace amount is belonged in the range of the allowable displacement amount is shorter than a time period previously determined and intermitting the idling operation in the case that the time for which the displace amount is belonged in the range of the allowable displacement amount become the time period previously determined and a fifth step (Step S10) for starting a process with respect to the workpiece in the case that the idling operation is finished are operated in order.

Claims

1. A method of processing a workpiece in a tool machine for processing said workpiece by relatively moving a tool with respect to said workpiece, said method comprising:

a first step of continuously measuring a position of a tip point of a tool attached to a main axis;

a second step of computing a displacement amount of said position of said tip point of said tool based on a result of a measurement in order;

a third step of observing whether said displacement amount of said position of said tip point of said tool is within a range of an allowable accuracy previously determined for a certain time period in order to judge whether said position of said tip portion of said tool thermally displaced is converged or not;

a fourth step of keeping an idling operation in the case that a time period that said displacement amount is within said range of said allowable accuracy is shorter than said certain time period previously determined so as to judge whether said position of said tip portion of said tool thermally displaced is converged or not and intermitting said idling operation in the case that said period that said displacement amount is within said range of said allowable accuracy is equal or longer than said certain time period previously determined; and

a fifth step of starting processing said workpiece in the case that said idling operation is intermitted in said fourth step.

2. A method of processing a workpiece in a tool machine as claimed in claim 1, wherein said position of said tip point of said tool is measured in one of a two dimensional mode and a three dimensional mode.

3. A method of processing a workpiece in a tool machine as claimed in claim 1, said method further comprising:

between the second and third steps,

a step of maintaining a measurement of said position of said tip point of said tool until a time period from starting said measurement of said position of said tip point of said tool passing over a longest measurement time period previously determined and stopping said measurement of said position of said tip point of said tool after said period from starting said measurement of said position of said tip point of said tool passing over the longest measurement time period previously determined.

4. A method of processing a workpiece in a tool machine as claimed in claim 2, further comprising:

between the second and third steps,

a step of maintaining a measurement of said position of said tip point of said tool until a time period from starting said measurement of said position of said tip point of said tool passing over a longest measurement time period previously determined and stopping said measurement of said position of said tip point of said tool after said period from starting said measurement of said position of said tip point of said tool passing over the longest measurement time period previously determined.

5. A behavior measurement device for processing a workpiece by controlling a relative position of a tool with respect to said workpiece in a tool machine, said behavior measurement device comprising:

measurement means that continuously measures a position of a tip point of said tool in one of a two dimensional mode and a three dimensional mode; and

control means that computes a displacement amount of said position of said tip point of said tool based on a result measured by said measurement means, observes a time period for which said displacement amount is maintained in a range of allowable displacement amount previously set, keeps an idling operation in case that said time period for which said displacement amount is maintained in a range of allowable displacement amount previously set is shorter than an allowable displacement maintaining time period previously set, and stops said idling operation in case that said time period in which said displacement amount is maintained in a range of allowable displacement amount previously set is equal or longer than said allowable displacement maintaining time period previously set.

6. A behavior measurement device in said tool machine as claimed in claim 5, wherein said measurement mean is photograph means that periodically photographs said position of said tip point of said tool at a constant time interval and said control means compute a displacement of said position of said tip point of said tool based on an image photographed by said photograph means.

7. A behavior measurement device in said tool machine as claimed in claim 5, wherein said measurement means is a laser interferometer.