(Part A) Machinerys Handbook 31st Edition Pages 1-1484

Machinery's Handbook, 31st Edition

Microcutting Tools

1165

Microtool

Laser displacement sensor

z

h 2 h 1 0

Part

Fixture

x

Vice

Fig. 9. Indirect Vertical Tool Offset Detection Technique. Microtool Damages

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10.0 μ m 1

3

50.0 μ m Fig. 10b. Built-up-edge at a cutting lip (label “2”) and side (label “3”) of a microdrill.

Fig. 10a. Abrasion with progressive wear from center to edge (label “1”) due to different cutting speed on a microdrill.

10.0 μ m

10.0 μ m

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6

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Fig. 10d. Chipping at the cutting edge of a carbide micromill due to local depletion of cobalt binder.

Fig. 10c. Adhesion wear (label “4”) due to built-up-edge on a micromill (label “5”).

Thermal effect is the second cause of tool damage. A cutting tool edge is softened at high machining temperature, deformed plastically, and removed from the tool. Both high-speed steel tools and carbide tools with high cobalt content are vulnerable to thermal damage. High temperature also promotes diffusion, i.e., atoms from the tool and workpiece move

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