How to reduce the influence of thermal deformation of NC lathe?

The thermal characteristic of NC lathe is one of the important factors affecting the machining accuracy. Because the spindle speed and feed speed of NC lathe are much higher than those of ordinary machine tools, and the hot cutting caused by large cutting parameters has a far more serious impact on the heat conduction of workpiece and machine tool components than ordinary machine tools, and the impact of thermal deformation on machining accuracy is often difficult to be corrected by the operator.

There are three main reasons for thermal deformation of CNC lathe:

1. Friction heat will be generated between the high-speed spindle and rolling bearing in the spindle box, resulting in thermal deformation of the spindle;

2. Friction heat is generated between the ball screw and the nut, causing thermal deformation of the guide rail;

3. Friction heat between guide rail and worktable causes guide rail heat.

How to reduce the thermal deformation of CNC lathe?

1. Improve the structural layout of CNC lathe

If the heat source is relatively symmetrical, the thermal symmetrical structure shall be adopted; The CNC lathe adopts the structure of inclined bed, flat bed and inclined sliding plate; Some heavy CNC machine tools adopt heat balance measures due to structural constraints.

2. Control temperature rise

For the heating part of NC lathe (such as spindle box, hydrostatic guide rail hydraulic oil, etc.), the methods of heat dissipation, air cooling and liquid cooling are adopted to control the temperature rise to absorb the heat emitted by the heat source. It is a measure to reduce the influence of thermal deformation, which is widely used in all kinds of NC machine tools.

3. Take strong cooling measures for cutting parts

When cutting with large cutting amount, the amount of hot chips falling on the worktable, bed and other parts is an important heat source. Modern CNC machine tools, especially machining centers and CNC lathes, generally use multi nozzle and large flow coolant to cool and remove these hot chips, and use large-capacity circulating heat dissipation or cooling device to control the temperature rise.

4. Thermal displacement compensation

Predict the law of thermal deformation, establish a mathematical model and store it in the computer for real-time compensation.