Sumitomo General Catalog 2025-2026

CBN / Coated CBN CBN Grade Guidance

Sintered Alloy

SINTERED COMPONENT MACHINING

● Advantages of cutting sintered components with CBN - SUMIBORON CBN - SUMIBORON has much smaller edge wear than carbide or cermet, and also has better wear resistance and can form a sharp edge easily. CBN - SUMIBORON is able to prevent burrs and chipping on the edges of the workpiece, achieving good machining precision and surface roughness.

Sintered Components Recommended Grade

Grade

Binder CBN Content (%) Grain Size (μm) Hardness HV (GPa)

TRS (GPa)

Main Coating Components Coating Thickness (μm)

Features

L

Co Compound Co Compound Co Compound Co Compound

Grade balancing ultimate cutting edge sharpness with fracture resistance, suitable for finishing of sintered alloy. Grade maintaining good cutting edge sharpness, suitable for finishing of sintered alloy. Grade balancing ultimate fracture resistance with wear resistance, suitable for roughing of sintered alloy. Grade exhibiting improved wear and fracture resistance in roughing of sintered alloy.

BN7115

90 to 95

1

41 to 44

2.2 to 2.3

-

-

BN7500

90 to 95

1

41 to 44

2.0 to 2.1

-

-

BN7125

90 to 95

2

41 to 44

1.9 to 2.0

-

-

BN7000

90 to 95

2

41 to 44

1.8 to 1.9

-

-

Transverse rupture strength measured with test piece equivalent to insert CBN layer

Performance

● Grade Performance Comparison

Carbide

D

Carbide

.0275 .0236 .0197 .0157 .0118 .0079 .0039

12

.0197

D

Cermet

D

10 8 6 4 2

.0157

D

D

D

.0018

SUMIBORON

Cermet

D D

D D

D

.0079

Carbide

D

DD

D D SUMIBORON

■ D

■ D

D D

Cermet

.0039

SUMIBORON

D D

D D

500 650

0

0

0

165 330

165 330 500 650 Cutting Speed v C (SFM)

165 330 500 650 Cutting Speed v C (SFM)

Cutting Speed v C (SFM)

For general powdered metal, carbide and cermet grades can perform up to v c = 330 SFM. However, around v c =400 SFM, wear becomes rapid and surface roughness deteriorates with increased burrs. On the other hand, CBN (SUMIBORON) exhibits stability and superior wear resistance, burr prevention and surface roughness, especially at high speeds.

Work Material: SMF4040 equivalent Machining Details: ø80-ø100 heavy interrupted facing with grooves and drilled holes (after 40 passes) Tool Cat. No.: TNGA331 Cutting Conditions: f = .0039 IPR, a p = .0039" Wet

Valve Seat Ring (VSR)

*VSR has both (Intake: IN) and (Exhaust: EX) with the exhaust generally being hardened.

Recommended Grade

Recommended Cutting Conditions

● Recommended Grade by Machining Details

Gasoline VSR material

Diesel VSR material

Cutting Speed v c (SFM)

Feed Rate f (IPR)

Depth of Cut a p (inch)

BN7000 BN7500

BN7000 BN7500

BN350

BN350

Plunge cut

165 to 415 .0012 to .0079 .0020 to .0197

BN7000 BN7500

BN7000 BN7500

BN500

BN500

Traverse cut

Workpiece Hardness (HV)

Low

300HV

High

Low

300HV

High

Application Examples

With superior fracture resistance, the BN7000 can achieve double our competitors' tool life

BN7000

3,200 holes

Part Material: Powdered Metal (150 to 250 HV) Machining Details: VSR(IN) 45° Surface Finishing Tool Cat. No.: TBGN521B Cutting Conditions: v c =330 SFM, f = .0031 IPR Wet

Competitor's CBN

800 holes

L9

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