Общий каталог Sumitomo 2018 - 2019 - страница 558

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Tool Failures and Tool Life

Forms of Tool Failures

Cat.No.Name of FailureCause of Failure
Resulting from Mechanical causes1~5 6 7Flank Wear Chipping FractureDue to the scratching effect of hard grains contained in the work material. Fine breakages caused by high cutting loads or chattering. Due to the impact of an excessive mechanical force acting on the cutting edge.
Resulting from Chemical reactions8 9 10 11Crater Wear Plastic Deformation Thermal Crack Built-up EdgeSwaft chips removing tool material as it flow over the top face at high temperatures. Cutting edge is depressed due to softening at high temperatures. Fatigue from rapid, repeated heating and cooling cycles during machining. Work material is pressure welded on the top face of the cutting edge.

Tool Wear

Forms of Tool Wear

Flank wear Crater wear Bad chip control Cutting edge fracture Burrs occur Creater wear KT Initial wear

Poor surface finish Side flank wear Sudden

VN increase 1 in wear Face flank wear Steady wear VN

2 Flank wear VB Cutting Time T (min) Cutting Time T (min) Edge wear VC Higher cutting force Wear is rapid initially, then it proceeds Poor machining accuracy more gradually in proportion with Crater wear is more progressive with

Burrs occur cutting time until a certain limit, beyond no sudden breakdown pattern.

which it increases rapidly again.

Tool Life (V-T)

Measure the relative tool lives of the specified wear, over a range of cutting speeds, then plot the tool life along the X-axis and the cutting speed along the Y-axis on a double logarithm graph. Flank wear Crater wear

V1 V2V3VVVV
1234
V4
VBKT
T 1 T2T 3T 4T’ 1 T’2T’3T’ 4
Cutting Time T (min)Cutting Time T (min)
VV1
1
VV2
2
VV3
3
VV4
4
T 1 T 2T 3T 4T’1T’2T’ 3T’4

Tool life (min) Tool life (min)