The thermal characteristics of CNC machine tools are one of the main factors affecting machining accuracy. Because the spindle speed and feed speed of CNC machine tools are much higher than those of ordinary machine tools, and the heat conduction of workpieces and machine parts caused by large cutting amount is much more serious than that of ordinary machine tools. The influence of thermal deformation on machining accuracy is often difficult for the operator modify. Therefore, special attention should be paid to methods to increase the influence of thermal deformation of CNC lathes.
There are several commonly used methods:
1. Improve the structure and structural design of CNC lathes: For example, the heat source adopts a thermally symmetrical structure; the CNC lathe adopts an inclined bed, a flat bed and an inclined slide structure; some heavy-duty CNC machine tools adopt a thermal equilibrium method due to structural limitations
2. Control the temperature rise: Use heat dissipation, air cooling and liquid cooling methods to control the temperature rise for parts of CNC machine tools that have a fever (such as the spindle box, hydrostatic guide rail hydraulic oil, etc.) to receive the heat recovered by the heat source. A countermeasure to increase the influence of thermal deformation is widely used.
3. Adopt strong cooling method for cutting parts: When cutting large amount of cutting, the fiery chip falling on the task table, bed and other parts is a main heat source. CNC machine tools, especially machining centers and CNC lathes, widely use multi-nozzle, large-flow coolant to cool and remove these hot chips, and use large-capacity cycles to dissipate the coolant or use a cooling device to cool the coolant to control the temperature rise.
4. Thermal displacement compensation: guess the discipline of thermal deformation, set up a mathematical model and save it in the computer to stop timely compensation.