#  Abrasive grain, hardness and concentration

### Diamond

Diamond is used in grinding wheels for grinding non-ferrous, non-metallic and composite materials. (Knoop hardness: 8,000–9,000).

 | **SD** | Used in our polyimide, hybrid and phenolic bonds.   The phenolic bond is suitable for dry grinding applications.   Available grit sizes: 1 to 35. |
|---|---|
| **ASD** | Its coating improves grain retention in the bond and heat dissipation, resulting in longer wheel life.   Used in our phenolic bonds for wet grinding.   Available grit sizes: 15 to 252. |
| **ASD6** | Specially coated to improve grain retention in the bond for wet grinding applications.   Used in our polyimide and hybrid bonds.   Available grit sizes: 46 to 252. |
| **DMD** | Used in our metal bonds.   Available grit sizes: 10 to 252. |
| **ASDC** | Specially coated for dry grinding applications.   Available grit sizes: 46 to 252. |
| **ASDK** | Ideal for grinding difficult-to-grind materials such as ceramics and cermets.   Used in our phenolic, polyimide and hybrid bonds.   Available grit sizes: 46 to 181. |

### Borazon

Cubic boron nitride (CBN) is used in grinding wheels for hardened ferrous materials and superalloys. (Knoop hardness: 4,600).

 | **B** | Used in our phenolic, polyimide and hybrid bonds.   Available grit sizes: 6 to 10. |
|---|---|
| **CBN** | Its coating improves grain retention in the bond and heat dissipation in the contact zone.   Used in our phenolic, polyimide and hybrid bonds.   Available grit sizes: 15 to 252. |
| **BM** | Used in our metal bonds.   Available grit sizes: 10 to 252. |

### Surface roughness (finish)

Approximate value, depending on the bond and workpiece material.

 | **Diamant** | D7 | D15 | D25 | D46 | D76 | D126 | D252 |  |
|---|:-:|:-:|:-:|:-:|:-:|:-:|:-:|:-:|
|  | D10 | D20 | D30 | D54 | D91 | D151 | - | - |
|  | - | - | - | D64 | D107 | D181 | - | - |
|  | **N1** | **N2** | **N3** | **N4** | **N5** | **N6** | **N7** | **N8** |
| **Ra (µm)** | 0,025 | 0,06 | 0,12 | 0,25 | 0,5 | 1,0 | 1,6 | 3,2 |
| **Rt (µm)** | 0,5 | 0,5 | 1,0 | 2,0 | 4,0 | 8,0 | 12,5 | 32,0 |
| **Rz (µm)** | 0,18 | 0,38 | 0,75 | 1,6 | 3,2 | 6,3 | 10,0 | 16,0 |
|  | **N1** | **N2** | **N3** | **N4** | **N5** | **N6** | **N7** | **N8** |
| **CBN** | - | B10 | B15 | B30 | B46 | B76 | B151 | B252 |
|  | - | B20 | - | B54 | B91 | B181 | B301 | - |
|  | - | - | - | B64 | B107 | - | - | - |

### Grit size

All our grit sizes are designated according to the FEPA standard.

 | **DIAMANT (FEPA)** | **CBN (FEPA)** | **MICRON** | **US MESH** |
|---|---|---|---|
| 1 | - | 1-2 μm | 14’000 |
| 3 | - | 2-4 μm | 8’000 |
| 5 | - | 4-6 μm | 6’000 |
| - | 6 | 4-8 μm | 3’000 |
| 7 | - | 6-8 μm | 2’500 |
| 10 | 10 | 6-12 μm | 1’800 |
| 15 | 15 | 10-20 μm | 1’200 |
| 20 | 20 | 15-25 μm | 1’000 |
| 25 | 25 | 20-30 μm | 800 |
| 30 | 30 | 22-36 μm | 700 |
| 35 | (40) | 30-40 μm | 600 |
| 46 | 46 | 38-45 μm | 325/400 |
| 54 | 54 | 45-53 μm | 270/325 |
| 64 | 64 | 53-63 μm | 230/270 |
| 76 | 76 | 63-75 μm | 200/230 |
| 91 | 91 | 75-90 μm | 170/200 |
| 107 | 107 | 90-106 μm | 140/170 |
| 126 | 126 | 106-125 μm | 120/140 |
| 151 | 151 | 125-150 μm | 100/120 |
| 181 | 181 | 150-180 μm | 80/100 |
| 252 | 252 | 212-250 μm | 60/70 |
| 301 | 301 | 250-300 μm | 50/60 |

### Grinding wheel grade

This letter is always placed before the concentration designation and indicates the modification of the base bond.

 | **Letter** | **Grade** |
|---|---|
| L | Soft |
| N | Medium |
| C | Hard (with diamond abrasive at concentration 100) |
| R | Hard (with CBN abrasive at concentration 100) |
| V | Very hard |

### Concentration

The same concentration values are used for both diamond and CBN abrasives and comply with international standards. The concentration indicates the amount of abrasive, expressed in carats per cm³.

(1 carat = 0.2 g)

 | **Concentration** | **CTS/CM3** |
|---|---|
| 25 | 1.1 |
| 50 | 2.2 |
| 75 | 3.3 |
| 100 | 4.4 |
| 125 | 5.5 |
| 150 | 6.6 |
| 175 | 7.7 |