Chipping Machining

Table of contents

- Classification of chipping machining

- The cutting edge

- How to choose proper cutting angles

- Properties of cutting-tool materials

- Survey of cutting-tool materials

Classification of chipping machining

Main group 3Cutting operations

With geometrically undefined cutting edges

With geometrically defined cutting edges

Turning Milling Drilling Shaping Broaching

Grinding Honing Lapping

The Cutting Edge

... clearance angle

... wedge angle

... rake angle

workpiece

chip

Cutting tool wedge

How to choose a proper clearance angle

small: 4° to 5° big: 8° to 10°

Used for

- high alloyed steel

- hardened steel

- short chipping materials

Used for

- aluminium, copper

- clastics

- long chipping materials

... clearance angle

: 5° to 8°

Standard for

steel and casting alloys

How to choose a proper rake angle

high positive

15° to 30°

positive

5° to 15°

much cutting force needed

great chip bending

Used for high alloyed steel, hardened steel

Little cutting force needed

easy chip removal

Used for aluminium, copper, plastics

... rake angle

negative

-5° to -25°

+ + -

Standard for

steel and casting alloys

How to choose a proper wedge angle

big small

strong cutting edge

Used for high alloyed steel, hardened steel

rough machining

weak cutting edge

Used for Aluminium, Plastics

finishing operations

... wedge angle

Depends on and

Cutting-tool materials

Properties

- Hardness:Sufficient hardness to resist wear and give an adequate life

- Hot hardness:The ability to retain its hardness at high temperatures generated at the tool point when cutting

- Compression strength:To avoid deformation and edge chipping

- Oxidation and diffusion resistance:To avoid build up edges and cratering

- Bending stability and ductility:To avoid insert breakage

- Resistance to temperature changes:To avoid insert fracture and breakage

Wear resistance Toughness

Cutting-tool materials

Toughness

Wea

r re

sist

ance

Ideal cutting-tool material

ceramicshigh-speed

steels (HSS)coated uncoated

Cemented carbide (hard metal)

coated

uncoatedhigh-carbon

steels

diamondpoly crystalline boron nitride (PKB), cubic boring nitride

(CBN)

Vocabulary

chipping machining Spanende Fertigung

cutting edge Schneide

cutting tool wedge Schneidkeil

turning, to turn Drehen, drehen

milling,to mill Fräsen, fräsen

drilling,to drill Bohren, bohren

shaping, to shape Stoßen, stoßen

broaching, to broach Räumen, räumen

grinding, to grind-ground-ground Schleifen, schleifen

honing, to hone Honen, honen

lapping, to lap Läppen, läppen

rake angle Spanwinkel

clearance angle Freiwinkel

wedge angle Keilwinkel

chip Span

alloyed steel legierter Stahl

hardened steel gehärteter Stahl

roughing, to rough Schruppen, schruppen

finishing, to finish Schlichten, schlichten

casting alloys Gusswerkstoffe

hot hardness Warmhärte

wear resistance Verschleißfestigkeit

compression strength Druckfestigkeit

toughness Zähigkeit

bending strength Biegefestigkeit

service life Standzeit

wear Verschleiß

edge chippingAusbröckeln der Schneide

cratering Kolkverschleiß

insert breakage Plattenbruch

fracture, crack Riss

tool point Werkzeugspitze

coated beschichtet

tungsten Wolfram

cemented carbide, hard metal Hartmetall

poly crystalline boron nitride polykristallines Bornitrid