Identification system of diamond & CBN wheels

Abrasive Type	Mesh Size	Hardness of Bond	Concentration	Bond Type	Depth of Super Abrasive Section
D: Natural Diamond SD: Synthetic Diamond SDC: Coated Synthetic Diamond cBN: Cubic Boron Nitride cBNC: Coated Cubic Boron Nitride	16 100 400 18 120 600 20 140 800 30 170 1000 40 200 1500 50 230 2000 60 270 2500 80 325 3000	J Softer  L N Medium P R Harder	25  Lower 50 75 100 125 150 175 200  Higher	B: Resin V: Vitrified M: Metal P: Electroplated	1.5 mm 2.0 mm 3.0 mm 5.0 mm

Grit size 
Diamond and CBN grit are available in many sizes and types.  The grit size is dependent upon the desired surface finish. In addition, the grit size also has an important effect on the grinding behaviour of the wheel. 
As far as the grit size is concerned, More SuperHard diamond complies with the FEPA standard.

Grit	Rough Grinding	Finish Grinding	Fine Grinding	Lapping
Diamond	D181 - D151	D126 - D91	D64 - D46	D30 - D15
CBN	B151	B126	B91	B46

Concentrations 
The content of diamond or CBN in the grinding rim is heavily dependent upon the application. Generally, where rapid stock removal of tungsten carbide or hardened steel is intended, a concentration of 75 to 125 is selected. When a good surface finish is demanded, lower concentrations in combination with finer diamond or CBN powder are required. Concentrations of up to 150 are used for profile grinding wheels and cylindrical wheels which have a small contact area. 

Degree of Concentration	Grain Content ct/cm³
200	8.8
175	7.7
150	6.6
125	5.5
100	4.4
75	3.3
50	2.2
25	1.1

Hardness Structure

The hardness of a CBN or diamond grinding wheel is identified by a letter after the grit size. Superabrasive however, do not cover the total range found in conventional wheels i.e. very soft A to very hard Z.
The hardness of resin bonded superabrasive is defined as follows:

Vitrified bonded wheels lie mainly in the hardness range from M to maximum R.
Harder specifications for 
► Long chip materials
► Narrow width of diamond & CBN layer
► Grinding where highly effective coolant used

Softer specification for
► Short - chip materials
► Wider layer of diamond & CBN
► Dry grinding or low concentration soluble
► Fine grit sizes

Basic ShapeS of Grinding Wheels
The standard code employs a series of numbers and letters to designate the shape of a diamond wheel. Its use involves four simple steps shown at right. In this example, the complete grinding wheel shape number would read: 6A2C




Workpiece surface finish and roughness clist

Ra μm	Rt μm	Rz μm	Roughness Class
0.025 0.05 0.06 0.08 0.1 0.12 0.16 0.2 0.25 0.31 0.4 0.5 0.6 0.8 1.0 1.25 1.6	0.2 0.4 0.5 0.6 0.8 1 1.25 1.5 2 2.5 3.2 4 5 6.3 8 10 12.5	0.16 0.32 0.38 0.5 0.6 0.75 1 1.25 1.6 2 2.5 3.2 4 5 6.3 8 10	N1 N2 N3 N4 N5 N6 N7

In actual industrial production, each shape of the grinding wheel can be replaced by a specific English code, and different shapes are used for different purposes. Here, you can know the shape codes of common grinding wheels and their applications:
 

Grinding Wheels Shape	Products Code	Application
Flat grinding wheels	P	External grinding, internal grinding, flat grinding, centerless grinding, thread grinding, and free grinding, etc.
Double beveled grinding wheels	PSX	Grinding gears, tooth surfaces, single threads, and grinding end faces in the round
Single bevel grinding wheels	PDX	Grinding various serrations, sharpening milling cutters, reamers, gear cutters, etc.
Single convex grinding wheels	PDT	Mainly to solve the manufacturing difficulties of grinding wheels with large diameter and thin thickness, same as flat grinding wheels
Single-face concave grinding wheels	PDA	Internal grinding and surface grinding, and external grinding for larger external diameter
Double-sided concave grinding wheels	PSA	External grinding, tool sharpening, and also for centerless grinding wheels and guide wheels
Cylindrical grinding wheels	N	Vertical shaft grinding
Cup wheels	B	Sharpening milling cutters, reamers, reaming drills, broaches, paper cutters, etc. Also used for flat and internal grinding
Bowl shaped grinding wheels	BW	Sharpening milling cutters, reamers, broaches, disc-type turning tools, inserting tools, reaming drills, etc. Also can be used for grinding machine guides, etc.
Dish grinding wheels	D	Grinding milling cutters, reamers, broaches, shaper cutters and other tools, large size is generally used for grinding gear teeth