Section N Technical Guide

Technical Guidance High Speed Machining of Cast Iron with CBN - SUMIBORON Edition

■ Advantages of using CBN - SUMIBORON for cast iron machining

● Higher accuracy

● Longer tool life at higher cutting speeds

Gray Cast Iron

Ductile Cast Iron

1,650

BNS800 BN7000 BN500

BNX10

3,300

Ceramic Coated carbide Cermet

BNS800 BN7000 BNC500

BNC500

1,650

660

N

Ceramic Coated carbide Cermet

BN7000

660

Ceramic Coated carbide Cermet

10 Tool Life Ratio

0.4 0.8 1.6 3.2

1

1

10

20

Good ←

Surface Roughness Standard Ra (μm)

Tool Life Ratio

■ Turning ● Cast iron structure and wear shape examples

.016

10 8 6 4 2 0

Part material

: Continuous cutting with Ductile Cast Iron

Dry Wet (water soluble)

Grey Cast Iron Ductile Cast Iron

.012

Tool material Tool Shape

: BN500

: SNG432 Cutting Conditions :  v c = 1,500 SFM a p =.0098” f =.0059 IPR Dry & Wet (water soluble)

Structure

.008

.004

0

1.5 3 4.5 6 7.5

Cutting speed ( v c ) (SFM) 650

1,300

Matrix

Pearlite

Pearlite + Ferrite

Cutting Length (miles)

Wet

Machine

: N/C lathe

WET (Water soluble)

DRY

Part Material

: Ductile Cast Iron

200HB Holder

: MTJNP2525

Tool Grade Tool Shape

: BN500

: TNMA332 Cutting Conditions :  v c =360 to 925 SFM f =.0039 IPR a p =.0039” Wet

Dry

Crater wear

For turning cast iron with CBN, cutting speeds ( v c ) should be 660 SFM and above. Wet cutting is recommended.

( v c =660 to 1,650 SFM)

■ Milling

BN Finish Mill EASY (for high-speed finishing of cast iron)

· Enables cutting with v c of 6,600 SFM · Surface finish roughness 3.2Rz (1.0Ra) · Economical insert reduces running costs. · Unit style enables easy runout adjustment. · Employs safe, anti-centrifugal-force construction for high-speed conditions.

250

.010

Cutting Conditions a p =.0197”, f z =.0059 IPR

Ceramic v c = 1,300 SFM

Ceramic

v c = 2000 SFM

200

.008

Dry

150

.006

v c = 3,300 SFM

v c = 2000 SFM

100

.004

Thermal cracks occur.

50

.002

v c = 5,000 SFM

Wet

1,000 0

0.0

0

Number of passes (Pass) 20 40 60 80 100 120 140 160 180 200

Cutting Speed (SFM) 1,500 2,000 2,500 3,000 3,500 4,000 4,500 5,000

Dry cutting is recommended for high speed milling of cast iron with CBN.

· Part material: Gray cast iron (FC250) · Cutting conditions: a p =.0197”, f z =.0039 IPR dry · Tool grade: BN7000

N66

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