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reason:
1. The workpiece will move downward under the action of drill bit penetration force, and the bit will bounce back after drilling
2. The rigidity of machine tool is insufficient
3. The drill material is not strong enough
4. The drill bit jumps too much
5. The clamping rigidity is not enough, and the drill bit slides
measures:
1. Reduce cutting speed
2. Increase the feed rate
3. Adjust cooling direction (internal cooling)
4. Add a chamfer
5. Check and adjust the coaxiality of drill bit
6. Check whether the rear angle is reasonable
2、 Ligament collapse
reason:
1. The workpiece will move downward under the action of drill bit penetration force, and the bit will bounce back after drilling
2. The rigidity of machine tool is insufficient
3. The drill material is not strong enough
4. The drill bit jumps too much
5. The clamping rigidity is not enough, and the drill bit slides
measures:
1. Select a bit with larger back cone
2. Check the runout range of spindle bit (< 0.02mm)
3. Drill the top hole with the preset center drill
4. Use more rigid drill bit and hydraulic chuck with necking sleeve or heat shrinkable set