The parameters used to designate grinding wheels made of bonded abrasives follow DIN 69 100 und DIN 69 186 (Figs. 3-13 and 3-14). The following specifications are required in the order indicated for the designation of conventional grinding components:
1. name
2. DIN-main number
3. form number
4. profile shape
5. nominal size
6. material
7. maximum operating speed.
Abrasive tools that are not suitable for all purposes must also be clearly denoted with a corresponding use limitation. These are defined in VBG 49 and consist of the prefix VE followed by a number [N. N.94a].
Grinding wheel DIN 69100 — 5A — 500x250x304 — P390 x F20 A60 L — 5V -50
Name
DIN — main number——-
Form number———————
Profile shape———————
Nominal size (List depending on shape)—————
Material
Abrasive—————————————————————
Grain size Grade
Structure————————————————————————-
Bond——————————————————————————
Maximum operating speed———————————————————-
Fig. 3-13. The designation of conventional grinding wheels
The shapes of the tools are differentiated numerically, the profile with uppercase letters. Code letters are appended to the shape designation. The nominal size of the abrasive tools are in the order and notation specified by DIN 69 100. The latter also stipulates which letters must also be supplied to label the dimensions.
A further subdivision for the specification of the abrasive material is shown in Fig. 3-15. According to it, among abrasives, we presently only distinguish corundum A and silicon carbide C. In order to differentiate particular corundum and silicon carbide types, like monocrystal corundum, the norm allows for a two-digit number in front of the designation.
DIN 69186 — A 13 x 160 x A 150 — L 8 V S
I 
I
Name ——————
DIN — main number
A: Quadrate
B: Rectangle Nominal size ( List depending on shape) ■
Abrasive —————————————————————
Grain size ——————————————————————
Grade—————————————————————————-
Structure —————————————————————————
Bond ———————————————————————————-
Model ————————————————————————————
Fig. 3-14. The structure of a honing stone designation
Grit size, from the coarsest to the finest, are designated with index numbers that are identical with the mesh count per inch in grit classification. The number 4 (grit diameter 3 mm) represents the coarsest granulation, 1200 (grit diameter 3 pm) the finest. Manufacturers supplement the numbers of the grit magnitudes with signs for combinations of various granulations. For example, for the nominal grit of granulation F 60 (FEPA-Standard 60), the designation 60 1 is often chosen.
The hardness of the grinding component is designated with code letters A to Z. A corresponds to the softest degree, Z to the hardest. Hardness is understood as resistance to abrasive grit break out from the grinding wheel, contingent on the adhesiveness of the bond at the grit and on the strength of the bond bridges. It is thus directly determined by the grinding component structure, i. e. by the volumetric composition of grit, bond, pore space and their distribution. The designation of the structure extends from 0 (closed structure) to 14 (very open structure).
Subsequent to the classification of the grinding component structure, the bond is characterised by letters, e. g. V for vitrified or B for resin bonds.
Concluding the grinding wheel designation in accordance with DIN 69 100 is a number representing the maximum wheel speed. For grinding components for general maximum wheel speeds corresponding to UVV-VBG 7n6, this specification is unnecessary. For grinding wheels built for operation with increased rotational speeds, the maximum operating speed must be provided in the designation according to paragraph 4 of the accident prevention regulations of the employer’s liability insurance association (UVV). Moreover, according to VBG 49 of the accident prevention regulations, the colour markings shown in table 3-4 must be applied to the grinding component in the form of coloured lines. Grinding wheels
tested with a trial run according to paragraph 4 of the UVV also receive a label with the letter P [N. N.94].
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Table 3-4. Labelling grinding wheels in order to indicate the maximum operating speed
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