The processing technology of CNC lathe is similar to that of ordinary lathe, but because CNC is clamped once and completes all turning processes continuously and automatically, the following aspects should be paid attention to.
1. Reasonable selection of cutting amount
For efficient metal cutting, the material to be processed, the cutting tool, and the cutting conditions are the three major factors. These determine the processing time, tool life, and processing quality. An economical and effective processing method must be a reasonable choice of cutting conditions.
The three elements of cutting conditions: cutting speed, feed rate, and cutting depth directly cause tool damage. With the increase of cutting speed, the temperature of the tool tip will rise, and mechanical, chemical, and thermal wear will occur. The tool life will be reduced by 1/2 when the cutting speed is increased.
The relationship between feed conditions and tool back wear occurs within a very small range. However, when the feed rate is large, the cutting temperature rises, and the back wear is large. It has less impact on the tool than the cutting speed. Although the impact of cutting depth on the tool is not as great as cutting speed and feed rate, when cutting at a small cutting depth, the cut material produces a hardened layer, which also affects the tool life.
Users should choose the cutting speed to be used according to the material to be processed, hardness, cutting state, material type, feed rate, cutting depth, etc. The selection of the most suitable processing conditions is based on these factors. Regular and stable wear to reach the life is the ideal condition. However, in actual operation, the choice of tool life is related to tool wear, change in the size of the workpiece, surface quality, cutting noise, processing heat, etc. When determining the processing conditions, it is necessary to study according to the actual situation. For difficult-to-process materials such as stainless steel and heat-resistant alloys, coolants can be used or blades with good rigidity can be selected.
2. Choose the right tool
- When rough turning, choose tools with high strength and good durability to meet the requirements of large back cutting amount and large feed amount during rough turning.
- When fine turning, choose tools with high precision and good durability to ensure the requirements of processing accuracy.
- In order to reduce tool change time and facilitate tool setting, machine clamping tools and machine clamping blades should be used as much as possible.
3.Choose the fixture reasonably
- Try to use general fixtures to clamp workpieces and avoid using special fixtures;
- The positioning datums of parts should be overlapped to reduce positioning errors.
4. Determine the processing route
The processing route refers to the trajectory and direction of the tool relative to the part during CNC machine tool processing.
- The processing accuracy and surface roughness requirements should be guaranteed;
- The processing route should be shortened as much as possible to reduce the tool idle travel time.
5. The relationship between processing route and processing allowance
At present, under the condition that CNC lathes have not yet been widely used, the excess of blanks, especially those containing forging and casting hard skin layers, should generally be processed on ordinary lathes. If CNC lathes must be used for processing, attention should be paid to the flexible arrangement of the program.
6. Key points for fixture installation
At present, the connection between the hydraulic chuck and the hydraulic clamping cylinder is achieved by a pull rod. The key points of hydraulic chuck clamping are as follows: first use a wrench to remove the nut on the hydraulic cylinder, remove the pull tube, and pull it out from the rear end of the spindle, then use a wrench to remove the chuck fixing screw to remove the chuck.
The finishing edge on the tool refers to a small section of the blade parallel to the tip of the tool ground in the direction of the secondary deflection angle behind the tool blade. It is mainly used for a secondary cutting after the blade cutting, which is equivalent to the finishing process to remove burrs and other scars. The purpose is to improve the surface roughness of the workpiece and is mostly used for finishing tools.
