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page 15

4. BASIC CUTTING TOOLS

4.1 CUTTING SPEEDS, FEEDS, TOOLS AND TIMES

Cutting is a balance between a number of factors,

-cutting slowly will add costly time to manufacturing operations.

-cutting faster will lead to decreased tool life, and extra time will be required to repair tools.

Some reasonable speeds and feeds for a single cutting point tool are given below [Krar],

MATERIAL

DEPTH (in.)

FEED PER REV. (ipr)

CUTTING SPEED (fpm)

 

 

 

 

Aluminum

0.005-0.015

0.002-0.005

700-1000

 

0.020-0.090

0.005-0.015

450-700

 

0.100-0.200

0.015-0.030

300-450

 

0.300-0.700

0.030-0.090

100-200

Brass, Bronze

0.005-0.015

0.002-0.005

700-800

 

0.020-0.090

0.005-0.015

600-700

 

0.100-0.200

0.015-0.030

500-600

 

0.300-0.700

0.030-0.090

200-400

cast iron (medium)

0.005-0.015

0.002-0.005

350-450

 

0.020-0.090

0.005-0.015

250-350

 

0.100-0.200

0.015-0.030

200-250

 

0.300-0.700

0.030-0.090

75-150

machine steel

0.005-0.015

0.002-0.005

700-1000

 

0.020-0.090

0.005-0.015

550-700

 

0.100-0.200

0.015-0.030

400-550

 

0.300-0.700

0.030-0.090

150-300

tool steel

0.005-0.015

0.002-0.005

500-750

 

0.020-0.090

0.005-0.015

400-500

 

0.100-0.200

0.015-0.030

300-400

 

0.300-0.700

0.030-0.090

100-300

stainless steel

0.005-0.015

0.002-0.005

375-500

 

0.020-0.090

0.005-0.015

300-375

 

0.100-0.200

0.015-0.030

250-300

 

0.300-0.700

0.030-0.090

75-175

titanium alloys

0.005-0.015

0.002-0.005

300-400

 

0.020-0.090

0.005-0.015

200-300

 

0.100-0.200

0.015-0.030

175-200

 

0.300-0.700

0.030-0.090

50-125

 

 

 

 

page 16

4.2 HIGH SPEED MACHINING

Usually spindle speeds above 10000 RPM, but this is highly relative to the cutting tool and work.

The cutting velocity is higher, but the feed/depth of the cut is reduced, the resulting mrr is still higher.

Higher spindle speeds call for new low inertia spindle, and tolerances as well. Small tolerance problems can result in unacceptable vibrations at these speeds.

The table below is an example of some cutting speeds [Ashley, 1995]

 

 

 

Solid tools - end mills, drills

Indexable tools - shell and face mills

 

 

 

WC, coated WC, PCD, ceramic

WC, ceramic, sialon, CBN, PCD

 

 

 

 

 

 

Work material

Typical

High

Typical

High

 

 

 

velocity

Speed

velocity

Speed

 

 

 

(fpm)

(fpm)

(fpm)

(fpm)

 

 

 

 

 

 

 

 

 

aluminum

1000+

10000+

2000+

12000+

 

 

 

 

 

(WC,PCD)

(WC,PCD)

 

(WC,PCD)

 

 

 

 

 

 

 

 

cast iron

 

 

 

 

 

 

 

 

soft

500

1200

1200

4000(sia.,cer.)

 

 

ductile

350

800

800

3000(cer.)

 

 

 

 

 

 

 

 

steel

 

 

 

 

 

 

 

 

free machining steel

350

1200

1200

2000

 

 

 

 

alloy

250

800

700

1200

 

 

 

 

stainless

350

500

500

900

 

 

 

 

hardness RC65

80

400

100(WC)

150(WC)

 

 

 

 

 

300(CBN,cer.)

600(CBN,cer.)

 

 

 

 

 

 

 

 

titanium

125

200

150

300

 

 

 

 

 

 

 

 

 

superalloy (Iconel)

150

250

275(WC)

1200(sia.,cer.)

 

 

 

 

 

700(sia.)