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Diamond

- Excellent hardness and wear resistance

- Breakable by impact

- Easy chemical reaction with ferrous metal -> unfavorable for grinding of steel

CBN(Cubic Boron Nitride)

- Excellent hardness

- Similar hardness, Young's modulus, thermal conductivity with diamond

- Stabe in the air up to 1200 degrees(Celsius)

- No chemical reaction with ferrous metal

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Type of Abrasive

Symbol Abrasive Bond
D Natural Diamond
SD Synthetic Diamond Resinoid, Metal, Vitrified, electroplated
CBN Cubic Boron Nitride
SDC Diamond coated with metel Resinoid
CBNC CBN with coated with metal

Grit Size

1) unit of abrasive size: mesh

 - The bigger mesh is, the smaller grit size is

ex) 140/170: Passing through 140mesh &  Not going through 170mesh mean 140mesh

Sort Grit size of Diamond & CBN
"Coarse grit size" #60 #80 #100 #120 #170 #200 #230 #270 #325
"Fine Grit size" #400 #600 #800 #1000 #1200 #1500 #2000 more than #30000

Grade

This means grade of abrasive binding power.

The standard is N

Close to A, it's soft & Close to Z, it's strong

 

J - L N - P R - T
Soft Medium Hard

 

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Wear Resistance is very important in grinding process

1) Good Bond: G/W with proper wear resistance shows long life

span & low grinding resistance as shown above

 

2) Hard Bond: G/W with hard bond has poor grindability

as shown above(No abrasive dropping out of bond after wearing)

 

3) Soft Bond: G/W with soft bond has short life span as shown above(Abrasive drops out of bond fastly and G/W’s wear is fast too)

Concentration

Quantity of Abrasive per unit area

As per high concentration, grinding tool's life span & quality(shipping, surface roughness) are improved. But, grindability  gets worse and tooling cost increases.

Concentration : 100 = 4.4cts/cc

Grit vol=25%

 

Bond type

Material for binding abrasive.

Classfied into Vitrified, Resinoid, Metal and Electroplated according to bond material.

Resinoid(B) non-pore type

Mainly used as bond, which is made of thermosetting phenol resin

Advantage: making the wheel efficient in grinding

process & making the wheel fine in surface roughness, chipping.

Demerit: Low wear resistance Polyamide resin with heat

resistance is used rather than phenol resin.

Metal(M) non-pore type

Binder made of copper, tin, tungsten carbide, iron and nickel

Retaining power & wear resistance of abrasive is high.

Used for precision cutting of concrete, stone, ferrite, glass, crystal, semi-conductor

Vitrified(V) pore type & non-pore type

No elastic deformation, excellent grindability,

intermediate performance between resinoid and metal

3 requisites for G/W(abrasive, binder, pore)

Excellent in strength, fragmentation, heat resistance, chip emission

Superb in truing, dressing

For workpiece with difficulty in grinding

Electroplated(P) non-pore type

Production of complicated shaped G/W is available.

Overhang from electroplated bond by 1/3 ~ 1/2 of abrasive diameter

Good chipping emission & grindability

Monolayer abrasive makes G/W's life span short.

Used for brake lining, ferrite, microscope, camera lens etc.

Applied Material

* CBN & Diamond Grinding Wheel for various materials

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