Tools to prevent breakage

3. Tools to prevent breakage

1) according to the characteristics of the materials and parts to be processed, the types and grades of the cutting tool materials should be reasonably selected

2) reasonable selection of geometric parameters of cutting tools. By adjusting the angle of front and back, the deflection angle of main and auxiliary parts, the inclination angle of Edge, etc.

Ensure that the cutting edge and tip have good strength. Grinding Negative Chamfer on cutting edge is an effective measure to prevent tool breakage

3) to ensure the quality of welding and edge grinding and avoid all kinds of defects caused by improper welding and edge grinding. The cutting tools used in key processes should be ground to improve the surface quality and checked for cracks;

4) reasonable selection of cutting parameters to avoid excessive cutting force and excessive cutting temperature to prevent tool breakage;

5) as far as possible to ensure that the process system has a good rigidity, reduce vibration;

6) take the correct operation method, as far as possible so that the tool does not bear or bear less mutation load.

The reason and countermeasure of cutting tool breakage

1) the blade number, specifications, such as the blade thickness is too thin or rough processing when the choice is too hard and too brittle brand.

COUNTERMEASURES: increase the thickness of the blade or the blade vertical installation, choose the bending strength and toughness of the higher brand.

2) improper selection of tool geometry parameters (e. g. too large front and back corners) .

Countermeasures: The following aspects can begin to redesign the tool. 1. Properly reduce the front and rear corners. 2 The negative edge inclination angle is larger. 3. Reduce the main deflection angle. 4 Use Large Negative Chamfer or edge arc. 5 repair the transition cutting edge, enhance the tip.

3) the blade welding process is not correct, resulting in excessive welding stress or welding cracks.

Countermeasures: 1 Avoid using three-sided closed blade slot structure. 2. Correct selection of solder. Avoid oxyacetylene flame heating welding, and after welding should be kept warm to eliminate the internal stress. 4 mechanical clamps are used as far as possible

4) improper grinding method, resulting in grinding stress and grinding crack, the PCBN milling cutter edge after grinding the tooth vibration pendulum is too large, so that individual teeth overload, will also cause beating cutter.

Countermeasures: 1 intermittent grinding or diamond grinding wheel grinding. Use a soft grinding wheel and trim frequently to keep the wheel sharp. 3 pay attention to the grinding quality and strictly control the oscillating quantity of the cutter teeth.

5) the amount of cutting is not reasonable, such as the amount is too large, the machine tool boring; intermittent cutting, cutting speed is too high, feed is too large, blank allowance is not uniform, cutting depth is too small; cutting high manganese steel and other materials with a greater tendency to work hardening, feed is too small, etc. .

COUNTERMEASURES: re-selection of cutting parameters.

6) the structural causes of the unevenness of the bottom surface of the groove or the overlength of the blade of the mechanical clamping and fixing tool.

Countermeasures: 1 repair the bottom of the knife groove. Reasonable arrangement of cutting fluid nozzle position. The hardened cutter bar is provided with a carbide gasket under the blade.

7) excessive tool wear.

COUNTERMEASURE: Change Cutter or change cutting edge in time.

8) the cutting fluid flow is insufficient or the filling method is incorrect, causing the blade to heat suddenly and crack.

COUNTERMEASURES: 1 increase the flow of cutting fluid. Reasonable arrangement of cutting fluid nozzle position. Effective cooling methods such as spray cooling were adopted to improve the cooling effect. Use * Cutting to reduce the impact on the blade.

9) incorrect tool installation, such as: cutting tool installation is too high or too low; end milling cutter using asymmetric forward milling and so on.

COUNTERMEASURE: Reinstall the cutter.

10) the rigidity of the process system is too poor, resulting in excessive cutting vibration.

COUNTERMEASURES: 1 increase the auxiliary support of the workpiece, improve the rigidity of the workpiece clamping. 2. Reduce the overhang length of the tool. Properly reduce the back angle of the cutter. 4 adopt other measures to eliminate vibration.

11) careless operation, such as: cutting tools from the middle of the workpiece, the Action Too Meng; has not been removed from the knife, that line stop.

COUNTERMEASURE: pay attention to the operation method.