Heat Management for High Precision Processing

The thermal deformation caused by the heat generated when the machine is running will have a great impact on the processing accuracy. Ultra-precision machine tools because the total quality of the machine is much higher than the material being cut, and the amount of cutting per unit of time is small, so only need to maintain the temperature of the machine environment constant, can avoid the problem of thermal deformation. However, the use conditions of high-precision machine tools are medium-volume and high-volume production, requiring high speed, large-cut processing, machine tools, tools, screws, spindles and other components in the process of processing will produce considerable heat, must be carefully considered in the machine tool design.

Taking DIXI's JIG series coordinate boring machine as an example, in order to control thermal deformation, a temperature control point is set up at the main heat source 7 of the machine tool, and a separate cooling cycle circuit is designed in each heat source and the heat generated by each heat source is calculated. The distribution of the machine temperature control points is shown in the figure above. The control points in the figure are: (1) ball nut, (2) screw bearing, (3) spindle bearing and motor, (4) B, C shaft direct drive motor, (5) electrical cabinet, (6) hydraulic system, (7) cooling circulation system.    During machine work, the coolant circulation system supplies coolant at a temperature of 2 degrees C lower than room temperature, depending on the heat generated from each heat source. Ensure that each cycle circuit provides a cooling amount slightly greater than the heat generated by the heat source to keep the thermal deformation of the machine within the per allowable range. Since the thermal deformation of the tool during cutting can not be completely avoided, the machine's nuncical control system can compensate for the Z-axis error caused by the tool. Finally, it must be pointed out that in addition to advanced functional components and technology, the manufacture of ultra-precision machine tools can not be separated from traditional technology, the assembly of an ultra-precision machine tools requires hundreds of hours of scraping work.