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| Diamond / CBN - Vitrified - Marking of Vitrified CBN and daimond grinding wheels |
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It is general practice in the grinding wheel industry that vitrified CBN and diamond grinding wheels are marked with manufacturer specific designations, often quite unintelligible for the user. In order to make the marking and designations on grinding wheels more transparent and comprehensible for the user, two typical Winterthur specifications, one of CBN and one of diamond, are “decoded” and explained in detail:
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| Grain CBN |
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19B
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126
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P
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13
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C
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VPMF
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600
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C100
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S55
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50m/s
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type
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Type of grain |
Colour |
Size |
Properties |
Application |
| 1B |
Black |
46 - 252 |
Regularly shaped micro-crystalline grain |
External cylindrical and surface grinding on machines of high rigidity. For nickel alloyed steel. |
| 3B |
Black |
46 - 252 |
Semi-blocky grain of medium resistance |
Universal application, can be easily dressed and crush-dressed. |
| 8B |
Light grey to black |
1 - 40 |
Blocky grain |
For finishing and super-finishing operations |
| 19B |
brownish |
46 - 181 |
Mono-crystalline grain of medium to high toughness |
For cylindrical grinding, creepfeed grinding, high metal removal rates, and high-alloy tool steel |
| 20B |
brownish |
46 - 252 |
Mono-crystalline blocky grain of high wear resistance |
For cylindrical grinding, creepfeed grinding, high metal removal rates, and high-alloy tool steel | | |
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| Diamond |
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1D |
126 |
P |
13 |
C |
VPMF |
634 |
C100 |
S55 |
50m/s |
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type |
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Type of grain |
Colour |
Size |
Properties |
Application |
| 1D |
yellowish |
46 - 252 |
Micro-fracturing properties, blocky crystal shape, high thermal resistance |
Universal application for tungsten carbide and ceramic materials |
| 76D |
yellowish |
46 - 252 |
Irregular shaped, friable grain |
Universal application for tungsten carbide and ceramic materials |
| 86D |
yellowish |
46 - 252 |
Blocky grain, high thermal stability, excellent resistance to breakage |
Cool grinding, ideal for grinding brittle materials, for large contact areas. |
| 81D |
light green to yellowish |
1 - 30 |
Blocky grain with sharp cutting edges |
Polishing and fine grinding of ceramic materials, PCD, PCBN and tungsten carbide |
| 84D |
grey |
2 - 40 |
Sharp cutting edges, brittle, low toughness |
Polishing and fine grinding of ceramic materials, PCD, PCBN and tungsten carbide |
| 87D |
light green to yellowish |
9 - 40 |
Natural diamond, free-cutting, brittle |
Fine grinding of ceramic materials and tungsten carbide | | |
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| CBN and diamond grain size |
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19B |
126 |
P |
13 |
C |
VPMF |
600 |
C100 |
S55 |
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size |
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FEPA grain size in mm |
US grain in mesh |
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251 |
60/70 |
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213 |
70/80 |
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181 |
80/100 |
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151 |
100/120 |
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126 |
120/140 |
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107 |
140/170 |
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91 |
170/200 |
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76 |
200/230 |
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64 |
230/270 |
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54 |
270/325 |
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46 |
325/400 |
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40 |
600 |
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30 |
700 |
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25 |
800 |
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20 |
1100 |
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15 |
1200 |
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9 |
1800 | | |
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In Europe, grain sizes of CBN and diamond are given as a statistical average in mm. For example, grain size B126 means that the average statistical grain diameter measures 0.126 mm (0.005”inch). The US system for sizing superabrasives is the same as for conventional abrasives such as aluminium oxide and silicon carbide and is given in mesh. Mesh sizes refer to the number of openings per linear inch on bronze sieves or silk screen cloth.
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Surface finish in relation to grain size
The achievable surface finish is not only a function of grain size selection but also depends on the material to be machined, the dressing conditions, depth of cut and other machining parameters, and on the grinding fluid in use.
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| Hardness grade |
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19B |
126 |
P |
13 |
C |
VPMF |
600 |
C100 |
S55 |
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wheel grade |
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Wheel grade letter |
Hardness |
Application |
| L,M,N,O |
soft |
Heat sensitive materials |
| P,Q,R |
medium |
General |
| R,S,T |
hard |
excellent profile and edge holding | | |
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| Structure |
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19B |
126 |
P |
13 |
C |
VPMF |
600 |
C100 |
S55 |
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structure |
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Structure |
Application |
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3 - 5 |
Standard structure for cylindrical and tool grinding |
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13 - 18 |
Induced porosity for heat-sensitive steel; surface and creepfeed grinding, tool grinding (flutes) | | |
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Supporting grain
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19B |
126 |
P |
13 |
C |
VPMF |
600 |
C100 |
S55 |
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Within the grinding wheel’s matrix CBN and/or diamond grains are often structurally supported by conventional abrasive grains. The designation of these supporting grains is given by letters ranging from A to F.
A = coarse supporting grain
F = fine supporting grain |
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Porosity
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19B |
126 |
P |
13 |
C |
VPMF |
600 |
C100 |
S55 |
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Porosity |
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Porosity |
Pore size |
| P Low porosity |
Induced porosity |
| PM_ Medium porosity |
F |
Fine pores |
| M |
Medium pores |
| G |
Coarse pores |
| PH_ High porosity |
F |
Fine pores |
| M |
Medium pores |
| G |
Coarse pores | | |
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Bond System CBN
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19B |
126 |
P |
13 |
C |
VPMF |
600 |
C100 |
S55 |
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Designation |
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Designation |
Hardness |
Application |
| V300 |
Soft |
Good surface finish, "soft" grinding properties |
| V |
Medium (Standard) |
Universal Application |
| V400 |
Hard |
Universal Application , high performance |
| V500 |
Very hard |
High metal removal rates and long life, excellent profile holding, medium surface speed operation up to 80 m/s (16,000 sfpm) |
| V600 |
Extremely hard |
High metal removal rates and long life, excellent profile holding, medium surface speed operation up to 125 m/s (25,000 sfpm) | | |
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Diamond
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1D |
126 |
P |
13 |
C |
VPMF |
634 |
C100 |
S55 |
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Designation |
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Designation |
Hardness |
Application |
| V334 |
Soft |
Good surface finish, "soft" grinding properties |
| V |
Medium (Standard) |
Universal Application |
| V434 |
Hard |
Universal Application , high performance |
| V534 |
Very hard |
High metal removal rates and long life, excellent profile holding, medium surface speed |
| V634 |
Extremely hard |
High metal removal rates and long life, excellent profile holding, higher surface speed |
| V11 |
Soft |
For PCD and PCBN grinding | | |
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Concentration
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19B |
126 |
P |
13 |
C |
VPMF |
634 |
C100 |
S55 |
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Designation |
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Designation |
Carat/cm3 |
Volume% |
Concentration |
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25
50 |
1.1
2.2 |
6.25
12.5 |
low |
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75
100 |
3.3
4.4 |
18.8
25 |
Standard |
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125
150 |
5.5
6.6 |
31.25
37 |
high |
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175
200 |
7.7
8.8 |
43.8
50 |
Highest concentration | | |
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Additional information
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19B |
126 |
P |
13 |
C |
VPMF |
634 |
C100 |
S55 |
50m/s |
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Suffix |
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Suffix |
Significance |
| /Sx (here S55) |
The rim is made up of x number of segments (here 55) |
| /H |
Tungsten carbide quill for mounted points |
| /K |
Plastic based dampening element |
| /KP |
Polypropylene dampening element in wheel body | | |
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Wheel peripheral (surface) speed
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19B |
126 |
P |
13 |
C |
VPMF |
634 |
C100 |
S55 |
50m/s |
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Vc | |
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Vc (m/s) |
Approval |
Colour code |
| 40 |
Not required |
Not applicable |
50
63 |
Clarify whether machine is considered open or fully enclosed |
blue /
yellow / |
80
100
125 |
Only for fully enclosed machines |
red /
green /
green/Blue // | | |
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