The reason why the PLC programming of CNC lathes is more complicated than that of milling machines is that the lathes have working requirements for tool change, hydraulic chuck and hydraulic tailstock.
The general CNC milling machine does not require tool change.
CNC lathe tool change can be programmed by macro program or directly in PLC program. Because the lathe tool changer has three tool change modes: "panel manual tool change", "screen manual tool change", and "automatic tool change". In comparison, it is easier to program the tool change program directly in the PLC program, while the tool change program in the machining center is simpler.
Using CNC machine tools to process workpieces is mainly to operate the CNC panel system. It is necessary to memorize the instructions on the panel and grasp the meaning of the instructions and the programming sequence of the workpiece.
The hydraulic chuck clamps the workpiece by hydraulic pressure acting on the chuck. However, it must be noted that there are two working methods for hydraulic chuck clamping workpieces on some lathes: one is the inward movement of common jaws to clamp the workpiece. The other is the outward expansion type, where the claw moves outward to tighten the workpiece.
Safe working requirements of the chuck: After entering the automatic cycle, the chuck cannot be loosened. After the automatic working cycle is over (still in automatic working mode), the chuck can be released to exchange the workpiece.
When the PLC program is processed, there is a problem of judging whether the working state of the chuck is internally tight or externally expanded.
