What to do if the drill bit always breaks in the process?

- Apr 01, 2021-

What to do if the drill bit always breaks in the process? Today, let's talk about application problems and measures.

1. Drill point wear

1

reason:

(1) The workpiece will move downward under the drilling force of the bit, and the bit will rebound after drilling.

(2) The rigidity of the machine tool is insufficient.

(3) The bit material is not strong enough.

(4) The drill bit jumps too much.

(5) The clamping rigidity is not enough and the bit slips.

measures:

1. Reduce the cutting speed.

2. Increase the feed rate.

3. Adjust the cooling direction (internal cooling).

4. Add a chamfer.

5. Check and adjust the coaxiality of the drill bit.

6. Check whether the rear angle is reasonable.

2. Ligament collapse

2

reason:

(1) The workpiece will move downward under the drilling force of the bit, and the bit will rebound after drilling.

(2) The rigidity of the machine tool is insufficient.

(3) The bit material is not strong enough.

(4) The drill bit jumps too much.

(5) The clamping rigidity is not enough and the bit slips.

measures:

(1)Choose a bit with a larger back cone.

(2) Check the runout range of spindle bit (< 0.02mm).

(3) Top hole with pre-determined core drill.

(4) Use a more rigid drill bit, hydraulic chuck with necking sleeve or heat shrinking kit.

3. Chip lump

3

reason:

Chemical reaction between cutting material and workpiece material (low carbon steel with high carbon content)

measures:

(1) Improve lubricant, increase oil or additive content.

(2) Increase the cutting speed, reduce the feed rate, reduce the contact time.

(3) If drilling aluminum, a surface polished uncoated drill bit can be used.

4. Broken knife

4

reason:

(1) The spiral groove of the drill bit is blocked by cutting and the chips are not discharged in time.

(2) When the hole is fast drilling, the feed rate is not reduced or the motor is changed to manual feed.

(3) When drilling soft metals such as brass, the back angle of the drill bit is too large, and the front angle is not polished, so that the drill bit rotates automatically.

(4) The sharpening of the drill edge is too sharp, resulting in the phenomenon of edge collapse, but the tool can not be withdrawn quickly.

measures:

(1) Shorten the tool change cycle.

(2) Perfect the installation and fixation, such as increasing the support area and clamping force.

(3) Check the spindle bearing and sliding groove.

(4) Use high precision tool holder, such as hydraulic tool holder.

(5) Use stronger materials