Cause: under the influence of internal and external heat sources, various parts of the gantry milling machine will have different degrees of thermal deformation, which will break the relative motion relationship between the workpiece and the cutter. For the gantry milling machine, because the whole processing process is controlled by the calculation command, the impact of thermal deformation is more serious.

In order to reduce the thermal deformation, the following measures are usually adopted in the structure of gantry milling machine.

1. After taking a series of measures to reduce the heat source, the thermal deformation will be improved. But it is very difficult or even impossible to completely eliminate the internal and external heat sources of gantry milling machine. Therefore, the temperature rise must be controlled by good heat dissipation and cooling to reduce the influence of heat source. The most effective method is forced cooling in the heating part of the gantry milling machine, or heating in the low-temperature part of the gantry milling machine, so that the temperature of each point of the gantry milling machine tends to be the same, which can reduce the warpage caused by the temperature difference.

2. In order to reduce the main heat source of thermal deformation, the heat source should be separated from the main machine as far as possible.

3. Improvement of headstock for the headstock of gantry milling machine, the thermal deformation of the spindle should occur 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 be reduced as much as possible to reduce the total amount of thermal deformation. At the same time, the temperature rise of the front and back of the main axle box should be consistent to avoid the inclination of the spindle after deformation.

4. Under the same heating condition, the improvement of gantry milling machine mechanism also has a great influence on the thermal deformation. For example, the single column mechanism used by gantry milling machine in the past may be replaced by double column mechanism. Because of the symmetry between the left and the right, the deformation of the main axis of the double column mechanism in other directions is very small except for the translation in the vertical direction, and the movement of the axis in the vertical direction can be easily compensated by a coordinate correction.