Thermal displacement compensating device and method for a machine tool

A thermal displacement compensating method for a machine tool, comprising:

• obtaining temperatures of respective blocks based on temperature information detected by temperature sensors arranged at predetermined portions on a structural body of the machine tool, the structural body of the machine tool divided into the respective blocks;
• performing a structural analysis by a finite element method based on the temperatures of the respective blocks obtained during the obtaining and inferring thermal displacement amounts of the structural body of the machine tool based on the structural analysis, wherein the finite element method analysis utilizes a plurality of nodes within each of the blocks, each node associated with a respective nodal temperature, each block associated with a respective range of temperatures within the block, and the temperatures in each of the respective blocks are assigned a uniform value;
• calculating a compensation value for a command position by a numerical control (NC) program of a movable body of the machine tool based on the thermal displacement amounts of the structural body of the machine tool inferred during the performing;
• compensating the command position by the compensation value obtained during the calculating, and
• changing a division mode of the blocks based on temperature information detected by the temperature sensors and so that the range of temperatures associated with each block is covered within a preset range.

A thermal displacement compensating device for a machine tool, comprising:

• temperature sensors arranged at predetermined portions on a structural body of the machine tool;
• and
• circuitry configured to:
• obtain temperatures of respective blocks based on temperature information detected by the temperature sensors, the structural body of the machine tool divided into the respective blocks;
• perform a structural analysis by a finite element method based on the temperatures of the respective blocks obtained by the circuitry and infer thermal displacement amounts of the structural body of the machine tool based on the structural analysis, wherein the finite element method analysis utilizes a plurality of nodes within each of the blocks, each node associated with a respective nodal temperature, each block associated with a respective range of temperatures within the block, and the temperatures in each of the respective blocks are assigned a uniform value;
• calculate a compensation value for a command position by a numerical control (NC) program of a movable body of the machine tool based on the thermal displacement amounts of the structural body of the machine tool inferred by the circuitry;
• and
• compensate the command position by the compensation value obtained by circuitry and so that the range of temperatures associated with each block is covered within a preset range.