Reasons And Countermeasures For Tool Breakage

1. Improper selection of blade brand and specifications, such as blade thickness being too thin or selecting a brand that is too hard or too brittle during rough machining.

Countermeasure:

 Increase the thickness of the blade or install the blade vertically, and choose a brand with higher bending strength and toughness.

2. Improper selection of tool geometry parameters (such as excessive front and rear angles, etc.).

Countermeasures:

You can redesign the tool from the following aspects.

1) Reduce the front and rear corners appropriately.

2) Use a larger negative blade inclination angle.

3) Reduce the main deflection angle.

4) Use larger negative chamfers or edge arcs.

5) Grind the transition cutting edge to enhance the blade tip.

3. The welding process of the blade is incorrect, resulting in excessive welding stress or welding cracks.

Countermeasures:

1) Avoid using a three sided closed blade groove structure.

2) Correct selection of solder.

3) Avoid using oxyacetylene flames for heating welding, and maintain insulation after welding to eliminate internal stress.

4) Try to use a mechanically clamped structure as much as possible

4. Improper blade grinding method, resulting in grinding stress and grinding cracks; Excessive vibration of the PCBN milling cutter teeth after grinding can cause excessive load on individual teeth, which can also lead to tool breakage.

Countermeasures:

1) Use intermittent grinding or diamond grinding wheels for grinding.

2) Choose a softer grinding wheel and regularly trim to keep the wheel sharp.

3) Pay attention to the grinding quality and strictly control the vibration of the milling cutter teeth.

5. The selection of cutting amount is unreasonable, and if the amount is too large, the machine tool may become stuck; During intermittent cutting, when the cutting speed is too high, the feed rate is too large, and the blank allowance is uneven, the cutting depth is too small; When cutting high manganese steel and other materials with high work hardening tendency, the feed rate is too small.

Countermeasure: 

Re select the cutting amount.

6. Structural reasons such as uneven bottom surface of the groove or excessive extension of the blade of the mechanically clamped cutting tool.

Countermeasures:

1) Trim the bottom surface of the knife groove.

2) Reasonably arrange the position of cutting fluid nozzles.

3) Add a hard alloy gasket under the blade for the hardened cutter bar.

7. Excessive tool wear.

Countermeasure:

 Change the tool or cutting edge in a timely manner.

Insufficient cutting fluid flow or incorrect filling method, resulting in sudden heating and cracking of the blade.

Countermeasures:

1) Increase the flow rate of cutting fluid.

2) Reasonably arrange the position of cutting fluid nozzles.

3) Use effective cooling methods such as spray cooling to improve the cooling effect.

4) Using * cutting to reduce impact on the blade.

9. Improper installation of cutting tools, such as cutting tools installed too high or too low; The end face milling cutter adopts asymmetric forward milling and other methods.

Countermeasure: 

Reinstall the tool.

10. The rigidity of the process system is too poor, causing excessive cutting vibration.

Countermeasures:

1) Increase the auxiliary support of the workpiece to improve the clamping rigidity of the workpiece.

2) Reduce the overhang length of the tool.

3) Reduce the back angle of the tool appropriately.

4) Adopt other vibration reduction measures.

11. Inadvertent operation, such as excessive action when the tool cuts through the middle of the workpiece; Stop the vehicle before retracting the knife.

Countermeasure: 

Pay attention to the operating methods.