Thermal error compensation method for machine tools

1. A thermal error compensation method for machine tools, comprising the steps of:

disposing at least one thermal sensor at positions neighboring to at least one heat source of a machine tool;

driving the machine tool to operate under a specific operation condition for enabling the at least one heat source to generate heat;

generating a thermal signal according to a temperature detected by the at least one thermal sensor; using a heat conducting calculation unit to access the thermal signal and information relating to the specific operation condition to be used in a calculation for obtaining and thus outputting at least one node temperature; and

using an error compensation unit to access the at least one node temperature to be used in a calculation for obtaining thermal error compensation values for the machine tool:

wherein the heat conducting calculation unit has a finite element structural model of the machine tool registered therein;

wherein a calculation performed by the heat conducting calculation unit for obtaining the at least one node temperature comprises the steps of:

accessing the thermal signal and the specific operation condition of the machine tool;

setting positions and temperatures of the at least one heat source based upon the finite element structural model:

calculating a temperature distribution relating to heat transfer in a structure of the machine tool; and

outputting node temperatures relating to positions on the machine tool which are configured with geometrical features and are heat sinks of the machine tool.

2. The method of claim 1 , wherein the thermal signal is an analog signal, and the analog thermal signal is designed to be received by an analog to digital converter where it is converted into a digital signal to be received by the heat conducting calculation unit.

3. The method of claim 1 , wherein the finite element structural model includes parameters relating to the geometrical structure and material of the machine tool.

4. The method of claim 1 , wherein the error compensation unit is embedded with a thermal error compensation model database and the thermal error compensation model database being established from various experimental data is a database of functions capable of describing relationships between temperature and thermal error of the machine tool when the machine is operating under different operation conditions.

5. The method of claim 4 , wherein the calculation for obtaining the thermal error compensation values performed by the error compensation unit comprises the steps of:

accessing the node temperatures;

searching the thermal error compensation model database for locating a thermal error compensation model according to the specific operation condition; and

inputting the node temperatures into the located thermal error compensation model for calculating thermal error compensation values for the machine tool.

6. The method of claim 4 , capable of using statistical means including multi-variable regression analysis and artificial neural network for describing the relationships between temperature and thermal error of the machine tool.

7. The method of claim 1 , wherein the at least one heat source of the machine tool is a location on the machine tool engaging/corresponding to its ambient environment, spindle, servo, servo motors, bearings, units, nuts, sliding blocks, and other modular identifiable components.

8. The method of claim 1 , wherein the machine tool is configured with a controller, capable of compensating a machining of the machine tool according to the thermal error compensation values.