The CNC vertical lathe is designed with a high-rigidity structure. The X-axis of the machine tool is designed with an over-positioning movable column structure and equipped with three guide rails. It has a large load-bearing section, so that the machine tool has a high rigidity and shock absorption, which can ensure high-precision and high-load cutting. The design of high efficiency and low noise makes the spindle of the machine tool adopt frequency conversion or AC servo main motor direct drive, and some models can be equipped with stepless speed change gearbox to increase the slow cutting force of the spindle. The front and rear ends of the high-rigidity spindle adopt imported high-precision spindle bearings, select ideal span support, and apply appropriate pre-tightening load, so that the spindle has high precision, high rigidity and high-speed rotation capacity. The machine tool is equipped with imported high-rigidity hydraulic reliable turret, which has high reliability and repeated positioning accuracy.
The thermal characteristics of CNC vertical lathe is one of the important factors affecting the machining accuracy. Because the spindle speed and feed rate of vertical lathe are much higher than those of ordinary machine tools, and the influence of hot cutting caused by large cutting parameters on the heat conduction of workpieces and machine parts is much more serious than that of ordinary machine tools, and the influence of thermal deformation on the machining accuracy is often difficult to be corrected by operators.
Therefore, special attention should be paid to the measures to reduce the thermal deformation of the vertical lathe. The common measures are as follows:
1. Improve the layout and structural design of the vertical lathe
For example, a thermal symmetrical structure is adopted for the heat source; The numerical control vertical lathe adopt a structure of an inclined lathe bed, a flat lathe bed and an inclined sliding plate; Heat balance measures are adopted in some heavy duty CNC machine tools due to structural limitations.
2. Control the temperature rise
Heat dissipation, air cooling and liquid cooling are adopted to control the temperature rise of the heating parts of the vertical lathe (such as the spindle box, hydraulic oil of the hydrostatic guide rail, etc.) To absorb the heat emitted by the heat source, which is a countermeasure widely used in various CNC machine tools to reduce the impact of thermal deformation.
3. Forced cooling measures shall be taken for the cutting parts.
The amount of hot chips that fall on the worktable, bed and other components is an important heat source when cutting with large cutting volume. Modern CNC machine tools, especially machining centers and CNC vertical lathes, generally use multi-nozzle and large-flow coolant to cool and remove these hot chips, and use large-capacity circulation or cooling devices to cool the coolant to control the temperature rise.
4. Thermal displacement compensation
The law of thermal deformation is predicted, and the mathematical model is established and stored in the computer for real-time compensation?