The influence of thermal deformation of CNC lathe system on accuracy

The characteristics of the thermal deformation of the spindle of the CNC lathe are analyzed, and on this basis, the relationship between the thermal deformation and the shape and position error of the processed parts is analyzed by using spatial analytical geometry, and the theoretical model of the processing thermal error is obtained, so as to provide a theoretical basis and technical basis for the realization of the thermal deformation error compensation of the spindle of the CNC lathe.

CNC lathe is a kind of high-performance, high-precision, low-noise tool walking automatic lathe. It can carry out uninterrupted repeated processing of copper, aluminum, iron, zinc alloy, plastic and other materials. It has the characteristics of automatic loading and unloading, and automatic feeding. Especially suitable for automobile and motorcycle parts, refrigeration accessories, plumbing valves, electronic appliances, mechanical hardware and other batch processing industries, can save a lot of labor. Commonly used automatic lathes include CNC lathes, hydraulic automatic lathes, pneumatic automatic lathes, cam automatic lathes, etc.

CNC lathe manufacturer's lathe thermal deformation caused by processing error lathe affected by the heat source, the temperature of each part will change, due to the uneven distribution of heat source and the complexity of the lathe structure, each component of the lathe will occur different degrees of thermal deformation, destroying the original geometric accuracy of the lathe, thus causing processing error. The main heat source of lathe-type lathes is the friction of bearing bearings, gears, clutches and other transmission pairs in the spindle box that increases the temperature of the spindle box and the bed, resulting in the raising and tilting of the spindle of the lathe. The displacement of the spindle in the horizontal direction is only lOμm, while the displacement in the vertical direction reaches 180~200μm. This has little impact on the machining accuracy of horizontal lathes with horizontal tool installation, but for automatic lathes and turret lathes with vertical tool installation, the impact on machining accuracy cannot be ignored.

In the cutting process, part of the kinetic energy of the tool or workpiece is consumed in the cutting work, and a considerable part is converted into the deformation energy of the cutting and the frictional heat between the chip and the tool, forming the tool, spindle and workpiece heating, and a large number of chip heat conduction to the lathe table fixture and other components. They directly affect the relative position of the tool and the workpiece.

Cooling is the reverse measure for the temperature increase of lathes, such as motor cooling, spindle component cooling, and infrastructure part cooling. Lathes often equip the electric control box with a refrigerator and force cooling.