Generally speaking, when we talk about the thermal deformation of CNC cutting machine, many people will focus on the scale deformation of cutting materials, etc., but as a thermal cutting processing equipment, CNC cutting machine itself may also cause structural deformation due to the change of temperature in frequent use and processing. Although as a production and processing equipment, CNC cutting machine will adopt a series of processes in the production and manufacturing process to minimize the impact of thermal deformation, as a user, in the ordinary use process, we should know more about this knowledge, standardize the operation procedures, and reduce the possible impact of thermal deformation.
1. Reduce fever
The main heat source that causes thermal deformation when the machine is heated inside should be separated from the main machine as far as possible.
2. Control temperature rise
After a series of measures are taken to reduce the heat source, the thermal deformation will be improved. But it is very difficult, even impossible, to completely eliminate the internal and external heat sources of machine tools. Therefore, it is necessary to control the temperature rise through good heat dissipation and cooling to reduce the influence of heat source. The most effective method is forced cooling at the heating part of the machine tool, or heating at the low temperature part of the machine tool, so that the temperature of each point of the machine tool tends to be the same, which can reduce the warpage caused by the temperature difference.
3. Improve machine tool mechanism
Under the same heating condition, the mechanism of machine tool also has a great influence on the thermal deformation. For example, the single column mechanism used by CNC machine tools in the past may be replaced by the double column mechanism. Due to the left and right symmetry, the main axis of the double column mechanism after heating has little deformation in other directions except for the translation in the vertical direction, and the axis movement in the vertical direction can be easily compensated by a coordinate correction.
The thermal deformation of the shaft occurs in the vertical direction of the cutting tool. This can minimize the influence of spindle thermal deformation on machining diameter. In the structure, the distance between the spindle center and the spindle to the ground should also be reduced as far as possible to reduce the total amount of thermal deformation. At the same time, the front and rear temperature rise of the main axle box should be consistent to avoid the inclination of the spindle after deformation.
The ball screw in CNC machine tools usually works under the condition of large load, high speed and poor heat dissipation, so it is easy to heat. The result of ball screw hot production is serious, especially in the open-loop system, it will make the feed system lose the positioning accuracy. At present, some machine tools use pre drawing method to reduce the thermal deformation of the lead screw. The thermal deformation which can not be eliminated by the above measures can be corrected by the compensation pulse sent by the CNC system according to the measurement results.