What should be paid attention to in the process of NC lathe machining. The machining process of CNC lathe is the same as that of ordinary lathe. However, since CNC is a clamping process, all the turning processes are finished continuously and automatically, the following aspects should be paid attention to.
1. Correct selection of cutting parameters
In terms of high efficiency metal cutting, the raw materials to be processed, cutting equipment and cutting conditions are three major factors. These decisions determine machining time, tool life and machining quality. The economic and useful machining method must be the correct choice of cutting conditions.
Three factors of cutting conditions: cutting speed, feed rate and cutting depth directly lead to tool damage. With the increase of cutting speed, the temperature of tool tip will rise, and mechanical, chemical and thermal wear will occur. If the cutting speed increases, the tool life will be reduced by 1 / 2.
The relationship between the feed condition and the wear of the back edge of the tool occurs within a very small boundary. But the feed rate is large, the cutting temperature rises, and the rear edge wear is large. It has less influence on the cutting tool than the cutting speed. Although the influence of cutting depth on the tool is not as high as the cutting speed and feed rate, when the cutting depth is small, the hard layer of the material to be cut will also affect the tool life.
Users should choose the cutting speed according to the raw material, hardness, cutting shape, raw material variety, feed rate, cutting depth, etc. The following table:
The selection of suitable processing conditions is based on these factors. Regular and stable wear and tear is the condition of dream.
However, in the essential work, the choice of tool life is related to tool wear, dimension change, surface quality, cutting noise, machining heat, etc. When confirming the processing conditions, the requirements are discussed according to the nature. As for stainless steel and heat-resistant alloy and other hard to process raw materials, it is advisable to choose a coolant or a rigid blade.
CNC lathe
2. Select tools correctly
1) During rough turning, the cutter with high strength and good durability shall be selected to meet the requirements of large back draft and large feed during rough turning.
2) When finishing, the cutting tools with high accuracy and good durability shall be selected to ensure the requirements of machining accuracy.
3) In order to reduce the time of tool change and make the tool setting easier, we should choose the clip knife and clip knife.
3. Select fixture correctly
1) Although the general fixture is used to clamp the workpiece, the special fixture shall not be used;
2） The positioning datum of parts are overlapped to reduce the positioning deviation.
4. Confirm the processing route
Machining route refers to the moving track and target of the tool relative to the part in the process of NC machining.
1) It shall be able to meet the requirements of machining accuracy and surface roughness;
2) It is necessary to reduce the processing route and the time of tool empty travel.
5. Correlation between machining route and machining allowance
At present, under the condition that the CNC lathe has not been widely used, it is usually necessary to place too much allowance on the blank, especially the allowance containing forging and casting hard skin layer on the ordinary lathe for processing. If the CNC lathe must be used for machining, it is necessary to pay attention to the sensitive placement of the program.
6. Key points of fixture installation
At present, the connection between hydraulic chuck and hydraulic clamping cylinder is completed by pull rod. The key points of hydraulic chuck clamping are as follows: first, remove the nut on the hydraulic cylinder with the handle, remove the pull tube, and pull it out from the rear end of the main shaft, and then remove the constant screw of the chuck with the handle to remove the chuck.
The polishing edge on the tool refers to a small section of the edge which is parallel to the tool tip milled by the target of the deviation angle of the back edge pair of the tool edge, which is mainly used for the second cutting after the cutting of the tool edge, which is equivalent to the direction burr in the finishing process. The goal is to increase the surface roughness of the workpiece, which is mostly used for the tool of finishing.
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