Built up edge

A built-up edge is an artificial cutting of editorial tools, which is formed by " Materialaufbackung ". It occurs mainly in the processing tough materials, especially at relatively small cut - and high feed speed on the chip, but also on the clearance face of the tool. The built-up edge is made possible by the smallest particles of material, the layer-like build up to a greater accumulation of material by pressure welding and adhesive phenomena. This has such a strong attachment that they can take over the function of the cutting edge.

Due to the built-up edge, the geometry of the cutting wedge changes towards a cutting wedge with small angle and large positive rake angle. The building up on the cutting material protrudes above the cutting out, breaks from time to time and becomes entrained by the flowing chip.

Such a cutting edge approach is to be avoided because it brings several disadvantages:

• The constant up and dismantling of the built-up edge has a vibration concern. By the Fort tearing of the built-up edge and the engagement of the original cutting, the cutting force decreases. This results in fluctuating cutting forces that can under poor conditions have a premature tool failure result.
• When shearing of the built-up edge usually break out, parts of the cutting edge, so that reinforced cutting tool wear.
• The built-up edge can tear up the workpiece surface and the structure adversely change ( Blank braking).
• The modified blade geometry leads to dimensional errors on the workpiece, the tool conditions must be corrected.

The formation of built-up edges can be reduced by:

• Increase the cutting speed
• Use of coated cutting tool materials
• Smooth, lapped clamping surfaces and sharp poor cutting
• Ample use of cooling lubricants
• Cutting materials with enhanced thermal conductivity
• Transition to carbide tools
• Enlargement of the Spanungsquerschnittes