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US 5,623,857 AGranted
Method and apparatus for compensating for thermal distortion for a machine tool
AssigneeHitachi Seiki Co., Ltd.
InventorHajime Sakuraba
Life of this patent
Estimating the term…
Abstract
A temperature change of a machine tool which is influenced by a heat generating source is detected by a temperature sensor. A temperature change having substantially the same time constant as a time constant of a thermal distortion of the machine tool is calculated by using the detected temperature change. A machining error is corrected on the basis of the thermal distortion corresponding to the calculated temperature change. According to a method and an apparatus for compensating for the thermal distortion in the machine tool, it is possible to perform the compensation relative to the thermal distortion with high precision. The invention is applied to a machine tool such as a machining center and an NC lathe.
Claims26
A method for compensating for a thermal distortion of a machine tool, comprising the steps of:
- detecting a temperature change of a machine structure which is influenced by a heat source;
- calculating a temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool by using the temperature change detected;
- and
- correcting a machining error on the basis of a thermal distortion that changes in correspondence with the calculated temperature change.
1 more element
A method for compensating for a thermal distortion of a machine tool, comprising the steps of:
- detecting a temperature change of a machine structure which is influenced by a heat source;
- calculating a temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool by using the temperature change detected;
- calculating a thermal distortion that changes in correspondence with the calculated temperature change;
- detecting a temperature change at a predetermined position of said machine structure;
- calculating a delay temperature change having substantially the same function of time as a lagging characteristic in which the thermal distortion is gradually offset from the calculated thermal distortion, by predicting a time lag to the detected temperature change;
- and
- correcting a machining error on the basis of a total value obtained by adding the lagging characteristic, that changes in correspondence with the delay temperature change, to the calculated thermal distortion.
4 more elements
A method for compensating for a thermal distortion of a machine tool, comprising the steps of:
- detecting temperature changes of a machine structure at at least two positions which are influenced by a heat source and in which the temperature changes have different time constants each other;
- mixing each temperature change detected, and then calculating a mixed temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool;
- and
- correcting a machining error on the basis of a thermal distortion that changes in correspondence with the mixed temperature change.
1 more element
A method for compensating for a thermal distortion of a machine tool, comprising the steps of:
- detecting a temperature change of a machine structure in the vicinity of a heat source;
- calculating a delay temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool, by predicting a time lag of the detected temperature change;
- and
- correcting a machining error on the basis of a thermal distortion that changes in correspondence with the delay temperature change.
1 more element
A method for compensating for a thermal distortion of a machine tool, comprising the steps of:
- detecting a temperature change at a predetermined position of a machine structure which is influenced by a heat source;
- calculating a temperature change of the heat source by using the detected temperature change;
- calculating a new temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool by using the temperature change of the heat source;
- and
- correcting a machining error on the basis of a thermal distortion that changes in correspondence with the new temperature change.
2 more elements
A method for compensating for a thermal distortion of a machine tool, comprising the steps of:
- detecting temperature changes of a machine structure at at least two positions which are influenced by a heat source and in which the temperature changes have different time constants each other;
- mixing each temperature change detected, and then calculating a mixed temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool;
- calculating a thermal distortion that changes in correspondence with the mixed temperature change;
- detecting a temperature change at a predetermined position of the machine structure;
- calculating a delay temperature change having substantially the same function of time as a lagging characteristic in which the thermal distortion is gradually offset from the calculated thermal distortion, by predicting a time lag to the detected temperature change;
- and
- correcting a machining error on the basis of a total value obtained by adding the lagging characteristic, that changes in correspondence with the delay temperature change, to the calculated thermal distortion.
4 more elements
A method for compensating for a thermal distortion of a machine tool, comprising the steps of:
- detecting a temperature change of a machine structure in the vicinity of a heat source;
- calculating a first delay temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool, by predicting a time lag to the detected temperature change;
- calculating a thermal distortion that changes in correspondence with the first delay temperature change;
- detecting a temperature change at a predetermined position of the machine structure;
- calculating a second delay temperature change having substantially the same function of time as a lagging characteristic in which the thermal distortion is gradually offset from the calculated thermal distortion, by predicting a time lag to the detected temperature change;
- and
- correcting a machining error on the basis of a total value obtained by adding the lagging characteristic, that changes in correspondence with the second delay temperature change, to the calculated thermal distortion.
4 more elements
A method for compensating for a thermal distortion of a machine tool, comprising the steps of:
- detecting a temperature change at a predetermined position of a machine structure which is influenced by a heat source;
- calculating a temperature change of the heat source by using the detected temperature change;
- calculating a new temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool by using the temperature change of the heat source;
- calculating a thermal distortion that changes in correspondence with the new temperature change;
- detecting a temperature change at a predetermined position of the machine structure;
- calculating a delay temperature change having substantially the same function of time as a lagging characteristic in which the thermal distortion is gradually offset from the calculated thermal distortion, by predicting a time lag to the detected temperature change;
- and
- correcting a machining error on the basis of a total value obtained by adding the lagging characteristic, that changes in correspondence with the delay temperature change, to the calculated thermal distortion.
5 more elements
An apparatus for compensating for a thermal distortion of a machine tool, comprising:
- temperature detecting means for detecting a temperature change of a machine structure which is influenced by a heat source;
- temperature calculating means for calculating a temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool by using the temperature change detected by said temperature detecting means;
- thermal distortion calculating means for calculating a thermal distortion that changes in correspondence with the temperature change calculated by said temperature calculating means;
- and
- compensating means for correcting a machining error on the basis of the thermal distortion calculated by said thermal distortion calculating means.
2 more elements
An apparatus for compensating for a thermal distortion of a machine tool, comprising:
- temperature detecting means for detecting a temperature change of a machine structure which is influenced by a heat source;
- temperature calculating means for calculating a temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool by using the temperature change detected by said temperature detecting means;
- thermal distortion calculating means for calculating a thermal distortion that changes in correspondence with the temperature change calculated by said temperature calculating means;
- temperature detecting means for separately detecting a temperature change at a suitable position of said machine structure if necessary;
- and
- delay temperature calculating means for calculating a delay temperature change having substantially the same function of time as a lagging characteristic in which the thermal distortion is gradually offset from the thermal distortion calculated by said thermal distortion calculating means, by predicting a time lag to the temperature change detected by any of said temperature detecting means;
- wherein a lagging characteristic that changes in correspondence with the delay temperature change is calculated, and at the same time, the lagging characteristic is added to the thermal distortion to thereby calculate a total value by said thermal distortion calculating means;
- and
- wherein a machining error is corrected on the basis of the total value by a compensating means.
6 more elements
An apparatus for compensating for a thermal distortion of a machine tool, comprising:
- temperature detecting means for detecting temperature changes of a machine structure at at least two positions which are influenced by a heat source and in which the temperature changes have different time constants each other;
- mixed temperature calculating means for mixing each temperature change detected by said temperature detecting means, and then calculating a mixed temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool in a predetermined axial direction;
- thermal distortion calculating means for calculating a thermal distortion that changes in correspondence with the mixed temperature change calculated by said mixed temperature calculating means;
- and
- compensating means for correcting a machining error on the basis of the thermal distortion in the predetermined axial direction calculated by said thermal distortion calculating means.
2 more elements
An apparatus for compensating for a thermal distortion of a machine tool, comprising:
- temperature detecting means for detecting a temperature change of a machine structure in the vicinity of a heat source;
- delay temperature calculating means for calculating a delay temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool in a predetermined axial direction, by predicting a time lag of the temperature change detected by said temperature detecting means;
- thermal distortion calculating means for calculating a thermal distortion that changes in correspondence with the delay temperature change calculated by said delay temperature calculating means;
- and
- compensating means for correcting a machining error on the basis of the thermal distortion in the predetermined axial direction calculated by said thermal distortion calculating means.
2 more elements
An apparatus for compensating for a thermal distortion of a machine tool, comprising:
- temperature detecting means for detecting a temperature change at a predetermined position of a machine structure which is influenced by a heat source;
- new temperature calculating means for calculating a temperature change of said heat source by using the temperature change detected by said temperature detecting means, and then calculating a new temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool in a predetermined axial direction by using the temperature change of said heat source;
- thermal distortion calculating means for calculating a thermal distortion that changes in correspondence with the temperature change calculated by said new temperature calculating means;
- and
- compensating means for correcting a machining error on the basis of the thermal distortion in the predetermined axial direction calculated by said thermal distortion calculating means.
2 more elements
An apparatus for compensating for a thermal distortion of a machine tool, comprising:
- temperature detecting means for detecting temperature changes of a machine structure at at least two positions which are influenced by a heat source and in which the temperature changes have different time constants each other;
- mixed temperature calculating means for mixing each temperature change detected by said temperature detecting means, and then calculating a mixed temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool in a predetermined axial direction;
- thermal distortion calculating means for calculating a thermal distortion that changes in correspondence with the mixed temperature change calculated by said mixed temperature calculating means;
- temperature detecting means for separately detecting a temperature change at a suitable position of said machine structure, if necessary;
- and
- delay temperature calculating means for calculating a delay temperature change having substantially the same function of time as a lagging characteristic in which the thermal distortion in the predetermined axial direction is gradually offset from an output of said thermal distortion calculating means, by predicting a time lag to the temperature change detected by any of said temperature detecting means;
- wherein the lagging characteristic that changes in correspondence with the delay temperature change is calculated, and at the same time, the lagging characteristic is added to the thermal distortion to thereby calculate a total value by said thermal distortion calculating means;
- and
- wherein a machining error is corrected on the basis of the total value by a compensating means.
6 more elements
An apparatus for compensating for a thermal distortion of a machine tool, comprising:
- temperature detecting means for detecting temperature change of a machine structure in the vicinity of a heat source;
- first delay temperature calculating means for calculating a delay temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool in a predetermined axial direction, by predicting a time lag of the temperature change detected by said temperature detecting means;
- thermal distortion calculating means for calculating a thermal distortion that changes in correspondence with the delay temperature change calculated by said first delay temperature calculating means;
- temperature detecting means for separately detecting a temperature change at a suitable position of said machine structure, if necessary;
- second delay temperature calculating means for calculating a delay temperature change having substantially the same function of time as a lagging characteristic in which the thermal distortion of said machine tool in the predetermined axial direction is gradually offset from the output of said thermal distortion calculating means, by predicting a time lag to the temperature change detected by any of said temperature detecting means;
- wherein the lagging characteristic that changes in correspondence with the delay temperature change calculated by said second delay temperature calculating means is calculated, and at the same time, the lagging characteristic is added to the thermal distortion to thereby calculate a total value by said thermal distortion calculating means;
- and
- wherein a machining error is corrected on the basis of the total value by a compensating means.
5 more elements
An apparatus for compensating for a thermal distortion of a machine tool, comprising:
- temperature detecting means for detecting a temperature change at predetermined positions of a machine structure which is influenced by a heat source;
- new temperature calculating means for calculating a temperature change of said heat source by using the temperature change detected by said temperature detecting means, and then calculating a new temperature change having substantially the same time constant as a time constant of the thermal distortion of said machine tool in a predetermined axial direction by using the temperature change of said heat source;
- thermal distortion calculating means for calculating a thermal distortion that changes in correspondence with the new temperature change calculated by said new temperature calculating means;
- temperature detecting means for separately detecting a temperature change at a suitable position of said machine structure, if necessary;
- delay temperature calculating means for calculating a delay temperature change having substantially the same function of time as a lagging characteristic in which the thermal distortion in the predetermined axial direction is gradually offset from the output of said thermal distortion calculating means, by predicting a time lag to the temperature change detected by any of said temperature detecting means;
- wherein the lagging characteristic that changes in correspondence with the delay temperature change is calculated, and at the same time, the lagging characteristic is added to the thermal distortion to thereby calculate a total value by said thermal distortion calculating means;
- and
- wherein a machining error is corrected on the basis of the total value by a compensating means.
5 more elements
Dependencies are inferred from the claim text.