The processing technology of CNC lathe is similar to that of general lathe. However, since CNC is one-time clamping and automatic processing, it can complete all turning processes. Therefore, attention should be paid to the following aspects.
- Select cutting parameters reasonably
For high efficiency metal cutting, the processed data, cutting tools and cutting conditions are the three major elements. These determine the processing time, tool life and processing quality. The economical and effective machining method must be the reasonable choice of cutting conditions.
The three factors of cutting conditions: cutting speed, feed rate and cutting depth directly cause tool damage. With the progress of cutting speed, the tool tip temperature will rise, which will produce mechanical, chemical and thermal wear. With the increase of cutting speed, the tool life will be reduced by 1 / 2.
The feed condition is related to the tool back wear in a very small range. But the feed rate is large, the cutting temperature rises, and the back wear is large. It has less effect on the tool than the cutting speed. Although the influence of cutting depth on the tool is not as great as the cutting speed and feed rate, but when the cutting depth is small, the hardened layer generated by the cutting data will also affect the tool life.
The user should select the cutting speed according to the processed data, hardness, cutting state, data type, feed rate, cutting depth, etc. As shown in the table below:
The most suitable processing conditions are selected on the basis of these elements. Regular, stable wear and tear to reach the longevity is the condition of ambition.
However, in practice, the selection of tool life is related to tool wear, dimension change, surface quality, cutting noise and processing heat. When confirming the processing conditions, the requirements should be studied according to the actual situation. For stainless steel and heat-resistant alloy and other difficult to machine data, you can choose coolant or choose a good rigid blade.
- Select cutting tools reasonably
1) In rough turning, the tool with high strength and good durability should be selected to meet the requirements of large back cutting amount and large feed rate.
2) When finishing turning, the tool with high precision and good durability should be selected to ensure the machining accuracy.
3) In order to reduce the tool changing time and facilitate tool setting, the machine clamping tool and machine clamping blade should be selected as far as possible.
CNC machining
- Select fixture reasonably
1) Try to select general fixture to clamp workpiece, and avoid using special fixture;
2) Parts positioning datum coincide to reduce positioning error.
- Confirm the processing road
Machining path refers to the path and direction of the tool relative to the parts in the process of NC machining.
1) The machining accuracy and surface roughness requirements shall be ensured;
2) The processing road should be shortened as far as possible and the tool idle travel time should be reduced.
- Contact between machining road and machining allowance
At present, under the condition that the CNC lathe has not been widely used, the excessive allowance on the blank, especially the allowance containing forging and casting hard layer, should be processed on the general lathe. If it is necessary to use CNC lathe processing, it is necessary to pay attention to the flexible organization of the program.
- Key to fixture installation
At present, the connection between the hydraulic chuck and the hydraulic clamping cylinder is completed by the pull rod. The key points of clamping the hydraulic chuck are as follows: firstly, remove the nut on the hydraulic cylinder with a handler, remove the pull pipe, and pull it out from the rear end of the spindle, and then remove the chuck fixing screw with the handler to remove the chuck.
The polishing edge on the cutting tool refers to a small section of the edge parallel to the tool tip grinded out in the direction of the offset angle behind the tool edge. It is mainly used for the secondary cutting after the cutting edge, which is equivalent to removing the burr and other scars in the finishing process. The purpose is to improve the surface roughness of the workpiece, and is mostly used in the tool for finishing.
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