Grinding Wheel and Grinding Related Knowledge

(20) H7 Tolerance Table (Axis & Hole)

2016-06-13T15:40:07+00:00

Axis Tolerance Table (ISO)
≥	<	c9	d8	e7	e8	f7	g6	h5	h6	h7	h8	js6	js7	k6	m6	n6	p6	p7	r6	s6
—	3	-60 -85	-20 -34	-14 -24	-14 -28	-6 - 16	-2 -8	0 -4	0 -6	0 -10	0 -14	±3	±5	+6 0	+8 +2	+10 +4	+12 +6	+16 +6	+16 +10	+20 +14
3	6	-70 -100	-30 -48	-20 -32	-20 -38	-10 -22	-4 -12	0 -5	0 -8	0 -12	0 -18	±4	±6	+9 +1	+12 +4	+16 +8	+20 +12	+24 +12	+23 +15	+27 +19
6	10	-80 -116	-40 -62	-25 -40	-25 -47	-13 -28	-5 -14	0 -6	0 -9	0 -15	0 -22	±4.5	±7	+10 +1	+15 +6	+19 +10	+24 +15	+30 +15	+28 +19	+32 +23
10	18	-95 -138	-50 -77	-32 -50	-32 -59	-16 -34	-6 -17	0 -8	0 -11	0 -18	0 -27	±5.5	±9	+12 +1	+18 +7	+23 +12	+29 +18	+36 +18	+34 +23	+39 +28
18	24	-110 -162	-65 -98	-40 -61	-40 -73	-20 -41	-7 -20	0 -9	0 -13	0 -21	0 -33	±6.5	±10	+15 +2	+21 +8	+28 +15	+35 +22	+43 +22	+41 +28	+48 +35
24	30	-110 -162	-65 -98	-40 -61	-40 -73	-20 -41	-7 -20	0 -9	0 -13	0 -21	0 -33	±6.5	±10	+15 +2	+21 +8	+28 +15	+35 +22	+43 +22	+41 +28	+48 +35
30	40	-120 -182	-80 -119	-50 -75	-50 -89	-25 -50	-9 -25	0 -11	0 -16	0 -25	0 -39	±8	±12	+18 +2	+25 +9	+33 +17	+42 +26	+51 +26	+50 +34	+59 +43
40	50	-130 -192	-80 -119	-50 -75	-50 -89	-25 -50	-9 -25	0 -11	0 -16	0 -25	0 -39	±8	±12	+18 +2	+25 +9	+33 +17	+42 +26	+51 +26	+50 +34	+59 +43
50	65	-140 -214	-100 -146	-60 -90	-60 -106	-30 -60	-10 -29	0 -13	0 -19	0 -30	0 -46	±9.5	±15	+21 +2	+31 +11	+39 +20	+51 +32	+62 +32	+60 +41	+72 +53
65	80	-150 -224	-100 -146	-60 -90	-60 -106	-30 -60	-10 -29	0 -13	0 -19	0 -30	0 -46	±9.5	±15	+21 +2	+31 +11	+39 +20	+51 +32	+62 +32	+62 +43	+78 +59
80	100	-170 -257	-120 -174	-72 -107	-72 -126	-36 -71	-12 -34	0 -15	0 -22	0 -35	0 -54	±11	±17	+25 +3	+35 +13	+45 +23	+59 +37	+72 +37	+73 +51	+93 +71
100	120	-180 -267	-120 -174	-72 -107	-72 -126	-36 -71	-12 -34	0 -15	0 -22	0 -35	0 -54	±11	±17	+25 +3	+35 +13	+45 +23	+59 +37	+72 +37	+76 +54	+101 +79
120	140	-200 -300	-145 -208	-85 -125	-85 -148	-43 -83	-14 -39	0 -18	0 -25	0 -40	0 -63	±12.5	±20	+28 +3	+40 +15	+52 +27	+68 +43	+83 +43	+88 +63	+117 +92
140	160	-210 -310																	+90 +65	+125 +100
160	180	-230 -330																	+93 +68	+133 +108
180	200	-240 -355	-170 -242	-100 -146	-100 -172	-50 -96	-15 -44	0 -20	0 -29	0 -46	0 -72	±14.5	±23	+33 +14	+46 +17	+60 +31	+79 +50	+96 +50	+106 +77	+151 +122
200	225	-260 -375																	+109 +80	+159 +130
225	250	-280 -395																	+113 +84	+169 +140
250	280	-300 -430	-190 -271	-110 -162	-110 -191	-56 -108	-17 -49	0 -23	0 -32	0 -52	0 -81	±16	±26	+36 +4	+52 +20	+66 +34	+88 +56	+108 +56	+126 +94	+190 +158
280	315	-330 -460	-190 -271	-110 -162	-110 -191	-56 -108	-17 -49	0 -23	0 -32	0 -52	0 -81	±16	±26	+36 +4	+52 +20	+66 +34	+88 +56	+108 +56	+130 +98	+202 +170
315	355	-360 -500	-210 -299	-125 -182	-125 -214	-62 -119	-18 -54	0 -25	0 -36	0 -57	0 -89	±18	±28	+40 +4	+57 +21	+73 +37	+98 +62	+119 +62	+114 +108	+226 +190
355	400	-400 540	-210 -299	-125 -182	-125 -214	-62 -119	-18 -54	0 -25	0 -36	0 -57	0 -89	±18	±28	+40 +4	+57 +21	+73 +37	+98 +62	+119 +62	+105 +114	+224 +208
400	450	-440 -540	-230 -327	-135 -198	-135 -232	-68 -131	-20 -60	0 -27	0 -40	0 -63	0 -97	±20	±31	+45 +5	+63 +23	+80 +40	+108 +68	+131 +68	+166 +126	+272 +232
450	500	-480 -635	-230 -327	-135 -198	-135 -232	-68 -131	-20 -60	0 -27	0 -40	0 -63	0 -97	±20	±31	+45 +5	+63 +23	+80 +40	+108 +68	+131 +68	+172 +132	+292 +252

315	355	-360 -500	-210 -299	-125 -182	-125 -214	-62 -119	-18 -54	0 -25	0 -36	0 -57	0 -89	±18	±28	+40 +4	+57 +21	+73 +37	+98 +62	+119 +62	+114 +108	+226 +190
355	400	-400 540																	+105 +114	+224 +208
400	450	-440 -540	-230 -327	-135 -198	-135 -232	-68 -131	-20 -60	0 -27	0 -40	0 -63	0 -97	±20	±31	+45 +5	+63 +23	+80 +40	+108 +68	+131 +68	+166 +126	+272 +232
450	500	-480 -635																	+172 +132	+292 +252

Hole Tolerance Table (ISO)
≥	<	B10	C9	D8	E7	E8	F7	G7	H6	H7	H8	JS7	K7	M7	N7	P7	R7	S7	T7
—	3	+180 +140	+85 +60	+34 +20	+24 +14	+28 +14	+16 +6	+12 +2	+6 0	+10 0	+14 0	±5	0 -10	-2 -12	-4 -14	-6 -16	-10 -20	-14 -24	—
3	6	+188 +140	+100 +70	+48 +30	+32 +20	+38 +20	+22 +10	+16 +4	+8 0	+12 0	+18 0	±6	+3 -9	0 -12	-4 -16	-8 -20	-11 -23	-15 -27	—
6	10	+208 +150	+116 +80	+62 +40	+40 +25	+47 +25	+28 +13	+20 +5	+9 0	+15 0	+22 0	±7	+5 -10	0 -15	-4 -19	-9 -24	-13 -28	-17 -32	—
10	14	+200 +150	+138 +95	+77 +50	+50 +32	+59 +32	+34 +16	+24 +6	+11 0	+18 0	+27 0	±9	+6 -12	0 -18	-5 -23	-11 -29	-16 -34	-21 -39	—
14	18	+200 +150	+138 +95	+77 +50	+50 +32	+59 +32	+34 +16	+24 +6	+11 0	+18 0	+27 0	±9	+6 -12	0 -18	-5 -23	-11 -29	-16 -34	-21 -39	—
18	24	+244 +160	+162 +110	+98 +65	+61 +40	+73 +40	+41 +20	+28 +7	+13 0	+21 0	+33 0	±10	+6 -15	0 -21	-7 -28	-14 -35	-20 -41	-27 -48	—
24	30	+244 +160	+162 +110	+98 +65	+61 +40	+73 +40	+41 +20	+28 +7	+13 0	+21 0	+33 0	±10	+6 -15	0 -21	-7 -28	-14 -35	-20 -41	-27 -48	-33 -54
30	40	+270 +170	+182 +120	+119 +80	+75 +50	+89 +50	+50 +25	+34 +9	+16 0	+25 0	+39 0	±12	+7 -18	0 -25	-8 -33	-17 -42	-25 -50	-34 -59	-39 -64
40	50	+280 +180	+192 +130	+119 +80	+75 +50	+89 +50	+50 +25	+34 +9	+16 0	+25 0	+39 0	±12	+7 -18	0 -25	-8 -33	-17 -42	-25 -50	-34 -59	-45 -70
50	65	+310 +190	+214 +140	+146 +100	+90 +60	+106 +60	+60 +30	+40 +10	+19 0	+30 0	+46 0	±15	+9 -21	0 -30	-9 -39	-21 -51	-30 -60	-42 -72	-55 -85
65	80	+320 +200	+224 +150	+146 +100	+90 +60	+106 +60	+60 +30	+40 +10	+19 0	+30 0	+46 0	±15	+9 -21	0 -30	-9 -39	-21 -51	-32 -62	-48 -78	-64 -94
80	100	+360 +220	+257 +170	+174 +120	+107 +72	+125 +72	+71 +36	+47 +12	+22 0	+35 0	+54 0	±17	+10 -25	0 -35	-10 -45	-24 -59	-38 -73	-58 -93	-78 -113
100	120	+380 +240	+267 +180	+174 +120	+107 +72	+125 +72	+71 +36	+47 +12	+22 0	+35 0	+54 0	±17	+10 -25	0 -35	-10 -45	-24 -59	-41 -76	-66 -101	-91 -126
120	140	+420 +260	+300 +200	+208 +145	+125 +85	+148 +85	+83 +43	+54 +14	+25 0	+40 0	+63 0	±20	+12 -28	0 -40	-12 -52	-28 -68	-48 -88	-77 -117	-107 -147
140	160	+440 +280	+310 +210														-50 -90	-85 -125	-119 -159
160	180	+470 +310	+330 +230														-53 -93	-93 -133	-131 -171
180	200	+525 +340	+355 +240	+242 +170	+146 +100	+172 +100	+96 +50	+61 +15	+29 0	+46 0	+72 0	±23	+13 -33	0 -46	-14 -60	-33 -79	-60 -106	-105 -151	-149 -195
200	225	+565 +380	+375 +260														-63 -109	-113 -159	-163 -209
225	250	+605 +420	+395 +280														-67 -113	-123 -169	-179 -225
250	280	+690 +480	+430 +300	+271 +190	+162 +110	+191 +110	+108 +56	+69 +17	+32 0	+52 0	+81 0	±26	+16 -36	0 -52	-14 -66	-36 -88	-74 -126	-138 -190	-198 -250
280	315	+750 +540	+460 +330	+271 +190	+162 +110	+191 +110	+108 +56	+69 +17	+32 0	+52 0	+81 0	±26	+16 -36	0 -52	-14 -66	-36 -88	-78 -130	-150 -202	-220 -272
315	355	+830 +600	+500 +360	+299 +210	+182 +125	+214 +125	+119 +62	+75 +18	+36 0	+57 0	+89 0	±28	+17 -40	0 -57	-16 -73	-41 -98	-87 -144	-169 -226	-247 -304
355	400	+910 +680	+540 +400	+299 +210	+182 +125	+214 +125	+119 +62	+75 +18	+36 0	+57 0	+89 0	±28	+17 -40	0 -57	-16 -73	-41 -98	-93 -150	-187 -244	-273 -330
400	450	+1010 +760	+595 +440	+327 +230	+198 +135	+232 +135	+131 +135	+83 +20	+40 0	+63 0	+97 0	±31	+18 -45	0 -63	-17 -80	-45 -108	-103 -166	-209 -272	-307 -370
450	500	+1090 +840	+635 +480	+327 +230	+198 +135	+232 +135	+131 +135	+83 +20	+40 0	+63 0	+97 0	±31	+18 -45	0 -63	-17 -80	-45 -108	-109 -172	-229 -292	-337

(19) Safety Operation of Grinding Wheels [3]

2014-06-27T09:05:15+00:00

Safe Operation

- Every piece of equipment comes with an owner's manual. The operator is advised to read the owner's manual to become familiar with the machine. Familiarization with the grinder will help you to know what the parts of the grinder, the uses of the grinder, the limitations of the grinder and warnings pertaining to the grinder. Before installing an abrasive wheel you should inspect it for damage and then use the ring test to listen for faults in the wheel.

Ring Test

- The ring test is used to test the integrity of the wheel. Faulty wheels can disintegrate and since they are rotating at high speeds can cause great damage and physical harm. To ring test, tap the wheel lightly with a non-metallic instrument, such as a screwdriver handle or plastic mallet. There should be ringing sound. If you hear more of a dead thud, then the wheel is probably faulty and should not be used.

The OSHA regulation 29 CFR 1910 sets the safe standard for "portable grinder" operation. Though these regulations pertain to operators of the grinder in the work force, they are good standards in the private sector as well. One of the biggest hazards of the operation is the wheel and its protections. The guard is designed to keep the operator safe from flying debris, from getting self or clothing caught in the wheel and to keep the operator safe if the wheel should prove faulty and come apart.

Personal Protective Equipment

- When operating the grinder several pieces of personal protection is recommended. Always protect your eyes. The eyes are some of the most sensitive and easily damaged organs of the body.

OSHA recognizes safety glasses that have Z87.1 on the lenses or inside leg. These glasses have passed rigorous testing and will not shatter when struck. Use a face shield if the operation will have a high probability of injuring your face. Protect your hearing. Grinding can be very loud. It is always a good idea to use hearing protection during loud operations.

Working Environment

- When working with a hand grinder you should consider the environment in which you work.

(1) Make sure that you have good lighting in order to see your work.
(2) Make sure that the area is free from hazards and clutter. Most accidents are from slips, trips and falls.
(3) Make sure that your clothing is not loose. Tuck in your shirt and have tight sleeves or roll them up. Be sure you are not wearing jewelry or other items like lanyards that can be caught in your work.
(4) Make sure that the area around you does not have slippery surfaces or fuels that may ignite. Be mindful of others around you. The wheel should be up to full speed before applying it to the work.

(18) Safety Operation of Grinding Wheels [2]

2014-06-27T08:44:07+00:00

Safety Guards
- All grinding wheels should feature safety guards or protection hoods. According to the United States Department of Labor, grinding wheel safety guards need to be durable enough to withstand the impact of a bursting grinding wheel. Grinding wheels can break without warning; safety guards keep broken fragments from injuring the operator. Side guards should cover a grinding wheel's spindle, flange, nut and about 75 percent of the diameter of the grinding wheel, according to Beacon Mutual Insurance.

Injury
- Wheel grinder operators always work with the risk of injury. Properly operating and maintaining wheel grinders greatly reduces the risk of injury linked with using them. According to Beacon Mutual Insurance, lacerations are the injury most commonly associated with wheel grinder accidents. Grinding wheels explode typically when a tool or piece of material gets stuck between the guard and the grinding wheel. Injuries to the groin and lower legs are common with wheel grinder accidents.

All grinding wheels feature a maximum operating speed provided by the manufacturer, never run grinding wheels at higher speeds than recommended by their manufacturers. Incorrectly or loosely holding a work piece against a wheel grinder can result in injury.

Personal Safety
- All wheel grinder operators should employ eye protection to prevent shards from a work piece flying off and severely damage the eyes. Eye goggles and hoods or shields are eye protection options. Clothing that comes in contact with the moving parts of a wheel grinder may get caught in the machine and cause injury. Do not wear neckties and loose clothing near active wheel grinders.

Components
- Not all grinding wheels are created equal; some grinding wheels are very brittle and can easily break if they are handled improperly, according to United States Department of Labor, consumers should be familiar with exactly what type of grinding wheel they are dealing with before attempting to operate the device.

(17) Safety Operation of Grinding Wheels [1]

2014-06-27T08:02:34+00:00

Eyes and hands injuries represent the most common types of injuries caused by using a grinding wheel. Most of the time, these injuries are caused by neglecting to observe proper safety procedures or inattention while the grinder is operating. If you follow the safety rules, you can almost entirely eliminate accidents and injuries with today's grinding wheels in the most secure way.

Mounting

- A grinding wheel, properly mounted and used, is relatively safe. In operation, the outside of the wheel may rotate at speeds in excess of 60 mph. Improper mounting can cause the wheel to vibrate and break apart at high speeds.

If the mounting is too tight or the grinding wheel mounting hole is too small or too large for the arbor, the wheel can break under pressure and at speed. Pieces of the fractured wheel can be flung off; they are responsible for most eye injuries associated with grinder accidents. Manufacturers recommend that you wear goggles and a face shield to protect your eyes. A face shield alone is not sufficient to protect from small particles that might ricochet up under the shield.

Wrong Wheel For The Job

- Grinding wheels come in varying strengths and textures for different kinds of jobs. Relatively soft wheels are used to prevent burning or distorting expensive or high-grade steels. Harder wheels are used for grinding or sharpening high-strength steel like cutting tools and drill bits. Cutter grinding wheels are used for cutting steel casings, steel plate, rods or sheet metal.

Using the wrong wheel can cause the wheel to wear too quickly and become unbalanced or fall apart. The metal being ground can be damaged and shed pieces of metal. If using a wet wheel, be sure to spin it dry afterward to prevent the coolant from breaking up the wheel.

Diamond Grinding Wheels & CBN Grinding Wheels

- Diamond tools, Grinding wheels, Rotary dresser, Diamond powder and Wrong Speed for the Grinding wheels are rated for specific speeds. The maximum working speed for each wheel is printed on a tag that comes with the wheel. Know what speed your grinder operates at. If it is a variable-speed grinder, know how fast each setting spins the wheel and do not exceed the manufacturer's recommended speed for the wheel you have mounted.

Poor Grinding Technique

- Poor grinding technique can result in abrasions or injuries. Among the causes are failing to hold your work correctly or brace your work agains a proper work rest; grinding on the side of a wheel not designed for that purpose; pressing too hard; forcing the grind too quickly on a cold wheel; grinding too high above the wheel center; failing to use wheel washers; or accidentally contacting unguarded moving parts. You can also cause wheel failure or accidents by trying to reach switches or controls that are out of reach while grinding or reaching across the wheel to make adjustments or manipulate controls while the grinder is spinning.

Side Pressure

- Too much side pressure, especially on thin straight wheels. Most wheels can stand up to a lot of straight on radial pressure, but too much side pressure or heavy pressure can overheat the wheel and break it. Bumping or pounding on the grinding wheel as its turning is dangerous.

Failure To Use Safety Hood

- Most modern grinders come with a clear plastic safety shield to deflect bits downward as they are ground off. The shield would not stop everything, but it is the first line of defense.

(16) Grinding Wheel and Its Binder

2014-06-26T13:46:02+00:00

STANDARD TYPES OF GRINDING WHEELS

There are various Standard Types of Grinding Wheels, Most Commonly Types are:

STRAIGHT
Straight wheels are commonly applied to internal, cylindrical, horizontal spindle, surface, tool, and offhand grinding and snagging.Type number 1 (1A1) wheels from 0.006-inch to 1/8-inch thick are used for cutting off stock and slotting.

CYLINDER
Cylinder wheels are to be arranged for grinding on either the periphery or side of the wheel.

TAPERED
Tapered wheels take tapered safety flanges to keep pieces from flying if the wheel is broken while snagging.

STRAIGHT CUP(CUPULATE)
The straight cup wheel is used primarily for surface grinding, but can also be used for offhand grinding of flat surfaces. Plain or beveled faces are available.

FLARING CUP(CUPULATE)
The flaring cup wheel is commonly used for tool grinding. With a resinoid bond, it is useful for snagging. Its face may be plain or beveled.

DISH
The chief use of the dish wheel is in tool work. Its thin edge can be inserted into narrow places, and it is convenient for grinding the faces of form-relieved milling cutters and broaches.

SAUCER(DISK-SHAPE)
The saucer wheel is also known as a saw gummer because it is used for sharpening saws.

ABRASIVE MATERIALS

The abrasive grains are the essential took of a grinding wheel. They actually cut small pieces or chips off the work as the wheel rotates. The shape of each grain is irregular with several sharp cutting edges. When these edges grow dull, the forces acting on the wheel tend to fracture the abrasive grains and produce new cutting edges.

ABRASIVES
Most grinding wheels are made of silicon carbide or aluminum oxide, or superhard materials like Diamond or CBN, both of which are artificial (manufactured synthetic) abrasives. Silicon carbide / Diamond is extremely hard but brittle. Aluminum oxide / CBN is slightly softer but is tougher than silicon carbide / Diamond. It dulls more quickly, but it does not fracture easily therefore it is better suited for grinding materials of relatively high tensile strength.

ABRASIVE GRAIN SIZE
Abrasive grains are selected according to the mesh of a sieve through which they are sorted. For example, grain number 40 indicates that the abrasive grain passes through a sieve having approximately 40 meshes to the linear inch. A grinding wheel is designated coarse, medium, or fine according to the size of the individual abrasive grains making up the wheel.

BOND

The abrasive particles in a grinding wheel are held in place by the bonding agent.
The percentage of bond in the wheel determines, to a great extent, the "hardness" or "grade" of the wheel. The greater the percentage and strength of the bond, the harder the grinding wheel will be. "Hard" wheels retain the cutting grains longer, while "soft" wheels release the grains quickly. If a grinding wheel is "too hard" for the job, it will glaze because the bond prevents dulled abrasive particles from being released so new grains can be exposed for cutting.
Besides controlling hardness and holding the abrasive, the bond also provides the proper safety factor at running speed. It holds the wheel together while centrifugal force is trying to tear it apart. The most common bonds used in grinding wheels are vitrified, silicate, shellac, resinoid, and rubber.

VITRIFIED
A vast majority of grinding wheels have a vitrified bond. Vitrified bonded wheels are unaffected by heat or cold and are made in a greater range of hardness than any other bond. They adapt to practically all types of grinding with one notable exception: if the wheel is not thick enough, it does not withstand side pressure as in the case of thin cutoff wheels.

SILICAYE (METALLIC / BRONZE)
Silicate bond releases the abrasive grains more readily than vitrified bond. Silicate bonded wheels are well suited for grinding where heat must be kept to a minimum, such as grinding edged cutting tools. It is not suited for heavy-duty grinding. Thin cutoff wheels are sometimes made with a shellac bond because it provides fast cool cutting.

RESINOID (RESIN)
Resinoid bond is strong and flexible. It is widely used in snagging wheels (for grinding irregularities from rough castings), which operate at 9,500 SFPM. It is also used in cutoff wheels.

RUBBER
In rubber-bonded wheels, pure rubber is mixed with sulfur. It is extremely flexible at operating speeds and permits the manufacture of grinding wheels as thin as 0.006 inch for slitting nibs. Most abrasive cutoff machine wheels have a rubber bond.

ELECTRO-PLATED
The electro-plated binder is adopting of Electro deposition method, to deposite the diamond/CBN powder upto the surface of the substrate (mostly in steel). The merits for such binder is mostly the very good shaping-kept, can achieve to vairous irregular grinding & polishing in irregular surfaces, angles etc.

GRADES OF HARDNESS

The grade of a grinding wheel designates the hardness of the bonded material. A soft wheel is one on which the cutting particles break away rapidly while a hard wheel is one on which the bond successfully opposes this breaking away of the abrasive grain.

Most wheels are graded according to hardness by a letter system. Most manufacturers of grinding abrasive wheels use a letter code ranging from A (very soft) to Z (very hard). Vitrified and silicate bonds usually range from very soft to very hard, shellac and resinoid bonds usually range from very soft to hard, and rubber bonds are limited to the medium to hard range.

The grade of hardness should be selected as carefully as the grain size. A grinding abrasive wheel that is too soft will wear away too rapidly, the abrasive grain will be discarded from the wheel before its useful life is realized. On the other hand, if the wheel is too hard for the job, the abrasive particles will become dull because the bond will not release the abrasive grain, and the wheel's efficiency will be impaired.

If the grain and bond materials in each of these are alike in size and hardness, the wheel with the wider spacing will be softer than the wheel with the closer grain spacing. Thus, the actual hardness of the grinding wheel is equally dependent on grade of hardness and spacing of the grains or structure.

(15) Brief Introduction about Diamond & CBN Materials

2014-06-26T09:45:08+00:00

Diamond & Cubic Boron Nitride (CBN) Materials

All grinding wheels with an abrasive layer of Synthetic Diamond or Cubic Boron Nitride (CBN) are grinding tools in the sense of DIN 8589. Their “cutting edges” are formed by the abrasive grits of Diamond or CBN.

Diamond and CBN grinding wheels are known and Diamond abrasives feature unsurpassed hardness and resistance to wear; hence their usage in the abrasive machining of hard, brittle and short-chipping materials such as glass, ceramics, quartz, ferrites, semiconductor materials, graphite,wear-resistant spray-on or weld-on alloys, glass fibre reinforced plastics and similar hard-to-machine materials. In special cases diamond tools may also be economical for machining cast steel and cast iron.

The properties of grinding wheels can be modified to enable them to perform both rough grinding and finish and fine grinding. Diamond wheels feature low wear even at high material removal rates; thus they can achieve the required shape, dimensional and surface tolerances even with difficult-to-grind materials.

Cost comparisons between conventional abrasives (aluminium oxide and silicon carbide) and diamond show that diamond used on appropriate grinding machines is more economical for the grinding of cemented carbides and similar hard-to-grind materials.

Cutting fluid should be used wherever possible in order to achieve high material removal rates coupled with low wear of the diamond grinding wheels.

Cubic Boron Nitride (CBN), like synthetic diamond, is produced high-pressure,high-temperature synthesis. The process used for incorporating it in grinding wheels is almost identical with that used for diamond.

CBN is the second hardest abrasive, surpassed only by diamond. Compared with diamond it offers economic advantages in the grinding of ferrous materials, such as steel. Compared with conventional abrasives it offers advantages especially in the grinding of hard-to-machine steels with large proportions of alloy and hardness ratings of 55 HRC and above, e.g. high-speed steels and chrome steels.

CBN wheels feature considerably lower wear, making it easier to achieve the necessary shape and dimension accuracies. A particular advantage in the grinding of hard-to-machine materials is that CBN wheels cause less damage to the surface integrity of the workpiece; thus HSS tools ground with CBN wheel often have longer life than those ground with conventional abrasives.

(14) Grinding Methods

2014-06-26T08:25:56+00:00

Grinding, or abrasive machining, once performed on conventional milling machines, lathes and shapers, are now performed on various types of grinding machines.

Grinding machines have advanced in design, construction, rigidity and application far more in the last decade than any other standard machine tool in the manufacturing industry. Grinding machines fall into five categories: surface grinders, cylindrical grinders, centerless grinders, internal grinders and specials.

Surface grinding

Surface grinders are used to produce flat, angular and irregular surfaces. In the surface grinding process, the grinding wheel revolves on a spindle; and the workpiece, mounted on either a reciprocating or a rotary table, is brought into contact with the grinding wheel.

Four types of surface grinders are commonly used in industry: the horizontal spindle/reciprocating table; the horizontal spindle/rotary table; the vertical spindle/reciprocating table; and the vertical spindle/rotary table.

Horizontal spindle/reciprocating table — This surface grinder is the most commonly used type in machining operations. It is available in various sizes to accommodate large or small workpieces. With this type of surface grinder, the work moves back and forth under the grinding wheel. The grinding wheel is mounted on a horizontal spindle and cuts on its periphery as it contacts the workpiece.

Horizontal spindle/rotary table — This surface grinder also has a horizontally mounted grinding wheel that cuts on its periphery. The workpiece rotates 360 degrees on a rotary table underneath the wheelhead. The wheelhead moves across the workpiece to provide the necessary cross feed movements.

Vertical spindle/reciprocating table — This type is particularly suited for grinding long and narrow castings, like the bedways of an engine lathe. It removes metal with the face of the grinder wheel while the work reciprocates under the wheel. The wheelhead assembly, as on most other types of surface grinders, moves vertically to control the depth of cut. The table moving laterally accomplishes cross feed.

Vertical spindle/rotary table — This grinding machine is capable of heavy cuts and high metal-removal rates. Vertical spindle machines use cup, cylinder, or segmented wheels. Many are equipped with multiple spindles to successively rough, semi-finish, and finish large castings, forgings, and welded fabrications.

Workholding devices — Almost any workholding device used on a milling machine or drill press can be used on surface grinders. However, the most common workholding device on surface grinders is a magnetic chuck.

Cylindrical grinding

Cylindrical grinding is the process of grinding the outside surfaces of a cylinder. These surfaces may be straight, tapered or contoured. Cylindrical grinding operations resemble lathe-turning operations. They replace the lathe when the workpiece is hardened or when extreme accuracy and superior finish are required. As the workpiece revolves, the grinding wheel, rotating much faster in the opposite direction, is brought into contact with the part. The workpiece and table reciprocate while in contact with the grinding wheel to remove material.

Workholding devices — Workholding devices and accessories used on center-type cylindrical grinders are similar to those used on engine lathes.

Independent, universal and collet chucks can be used on cylindrical grinders when the work is odd-shaped or contains no center hole. These also are used for internal grinding operations.

Centerless grinding

Centerless grinding machines eliminate the need to have center holes for the work or to use workholding devices. In centerless grinding, the workpiece rests on a workrest blade and is backed up by a second wheel, called the regulating wheel. The rotation of the grinding wheel pushes the workpiece down on the workrest blade and against the regulating wheel. The regulating wheel, usually made of a rubber-bonded abrasive, rotates in the same direction as the grinding wheel and controls the longitudinal feed of the work when set at a slight angle. By changing this angle and the speed of the wheel, the workpiece feed rate can be changed.

Internal grinding

Internal grinders are used to finish straight, tapered or formed holes accurately. The most popular internal grinder is similar in operation to a boring operation in a lathe: The workpiece is held by a workholding device, usually a chuck or collet, and revolved by a motorized headstock. A separate motor head in the same direction as the workpiece revolves the grinding wheel. It can be fed in and out of the work and also adjusted for depth of cut.

Special grinding processes

Special types of grinders are grinding machines made for specific types of work and operations, for example:

Tool and cutter grinders. These grinding machines are designed to sharpen milling cutters, reamers, taps and other machine tool cutters. The general-purpose cutter grinder is the most popular and versatile tool-grinding machine. Various attachments are available for sharpening most types of cutting tools.

Jig grinding machines. Jig grinders were developed to locate and accurately grind tapered or straight holes. Jig grinders are equipped with a high-speed vertical spindle for holding and driving the grinding wheel. They utilize the same precision locating system as do jig borers.

Thread grinding machines. These are special grinders that resemble the cylindrical grinder. They must have a precision lead screw to produce the correct pitch, or lead, on a threaded part. Thread grinding machines also have a means of dressing or truing the cutting periphery of the grinding wheel so that it will produce a precise thread form on the part.

Creep-feed grinding

Traditionally, grinding has been associated with small rates of metal removal and fine finishing operations. However, grinding also can be used for large-scale metal-removal operations, similar to milling, broaching, and planning. In creep-feed grinding, developed in the late 1950s, the wheel depth of cut is as much as 0.25 in. and the workpiece speed is low.

Its overall competitive position with other material-removal processes indicates that creep-feed grinding can be economical for specific applications, such as in grinding shaped punches, twist-drill flutes, and various complex super alloy parts. The wheel is dressed to the shape of the workpiece to be produced. Although generally one pass is sufficient, a second pass may be necessary for improved surface finish.

Grinding wheel wear

The wear of a grinding wheel may be caused by three actions: attrition or wearing down, shattering of the grains, or breaking of the bond.

In most grinding processes, all three mechanisms are active to some extent. Attritions wear is not desirable because the dulled grains reduce the efficiency of the process, resulting in increased power consumption, higher surface temperatures, and surface damage. However, attrition must go on to some extent, with the forces on the grit being increased until they are high enough to shatter the grit or break the bond posts holding the dulled grit. The action of particles breaking away from the grains serves to keep the wheel sharp without excessive wear. However, the grains must eventually break from the bond or the wheel will have to be dressed. Rupturing the bond post that holds the grit allows dull grains to be sloughed off, exposing new sharp edges. If this occurs too readily, the wheel diameter wears down too fast. This raises wheel costs and prohibits close sizing on consecutive parts.

G-ratio — The G-ratio is the ratio of the amount of stock removed versus the amount of wear on the wheel, measured in cubic inches per minute. This ratio will vary from 1.0 to 5.0 in very rough grinding, and up to 25.0 to 50.0 in finish grinding.

Even though grinding wheels are fairly expensive a high G-ratio is not necessarily economical, as this may mean a slower rate of stock removal. It often takes some experimenting to find the wheel-metal combination, which is most economical for a job.

Attritions wear — Attritions wear is responsible for the so-called "glazed" wheel that occurs when flat areas are worn on the abrasive grains but the forces are not high enough to break the dull grains out of the wheel face. Attritions wear of the wheel occurs most often when fine cuts are taken on hard abrasive materials. Taking heavier cuts or using a softer wheel that will allow the grains to break out can often avoid it.

Grain fracture — The forces that cause the grain to shatter may arise from the cutting forces acting on the wheel, thermal conditions, shock loading, welding action between the grit and the chip, or combinations of these factors. In finish grinding, this type of wheel wear is desirable, because it keeps sharp edges exposed, and still results in a low rate of wheel wear. In time, the wheel may become 'loaded' and noisy, and require dressing.

A loaded wheel should be dressed by taking a few deep cuts with the diamond so that the metal-charged layer is removed, and the chips are not just pushed further into the wheel. Then, it should be finish-dressed according to the application requirements.

Bond fracture — It is desirable to have worn grit break out of the wheel so that new cutting edges will be exposed. This breaking down of the bond should progress fast enough so that heat generation is sufficiently low to avoid surface damage. On the other hand, bond breakdown should be slow enough so that wheel costs are not prohibitive. Normally, this means choosing the proper wheel grade for the job. Certain bond hardness is required to hold the grain in place. Softer wheels crumble too fast, while harder wheels hold the dull grit too long.

Coded abrasives

Typical examples of coated abrasives are sandpaper and emery cloth. The grains used in coated abrasives are more pointed than those used for grinding wheels. The grains are electro-statically deposited on flexible backing material, such as paper or cloth. The matrix or coating is made of resin.

Coated abrasives are available as sheets, belts and disks and usually have a much more open structure than the abrasives on grinding wheels. Coated abrasives are used extensively in finishing flat or curved surfaces of metallic or nonmetallic parts, and in woodworking. The surface finishes obtained depend primarily on the grain sizes.

Abrasive belt machining — Coated abrasives are also used as belts for high-rate material removal. Belt grinding has become an important production process, in some cases replacing conventional grinding operations such as the grinding of camshafts. Belt speeds are usually in the range of 2,500 to 6,000 ft/min. Machines for abrasive-belt operations require proper belt support and rigid construction to minimize vibration.

Grindability

Grindability, in a like manner as machinability, may be thought of as the ease with which material can be removed from the workpiece by the action of the grinding wheel. Surface finish, power consumption, and tool (wheel) life can be considered as fundamental criteria of the grindability of metals. In addition, there are the important factors of chip formation and susceptibility to damaging the workpiece. Chip formation, which leads to a ‘loaded’ wheel, is detrimental.

The most important machine setting affecting machinability, the cutting speed, is not as important an influence on grindability because grinding is done at more or less constant speed. Instead, the important factor becomes the nature of the grinding wheel. The type of grit, grit size, bond material, hardness and structure of the wheel all influence the grindability of the workpiece. The problems of tool material and configuration variables were discussed in connection with machinability.

In grinding operations like snagging and cut-off work, the surface finish, and even the metallurgical damage the workpiece, may become relatively unimportant. Wheel life and the rate of cut obtainable then become the criteria of grindability.

The best way to determine grindability is to start with the selection of the proper wheel. Beginning with the manufacturer's recommended grade for the conditions of the job and then trying wheels on each side of this grade will do this. Any improvement or deterioration in the grinding action, as evidenced by wheel wear, surface finish, or damage to the workpiece, can be noted. After the proper wheel has been chosen, wheel life data may be obtained. Usually, this can be done during the production run.

Some of the factors to consider in establishing grindability ratings are discussed in the following examples relative to the performance metals.

Cemented carbide material cannot be ground with aluminum-oxide grit wheels. Although it can be ground with pure silicon-carbide wheels, the grinding ratio is very low and the material is easily damaged. Carbide is easily ground with diamond wheels if light cuts are taken to prevent damage to the workpiece material. However, diamond-grit wheels are quite expensive, and the overall grindability of this material is very low.

High-speed steel can be ground quite successfully with aluminum-oxide grit wheels. The grinding ratio is low, the relative power consumption is high, and the possibility of damage to the workpiece is always present. Overall grindability is quite low.

Hardened steel (medium hard alloy or plain carbon steels) is easily ground with aluminum-oxide wheels. The grinding ratio is good, and damage to the workpiece is not a serious problem. The grindability rating is good.

Soft steels (annealed plain carbon steels) grind with relatively low power consumption. Aluminum-oxide wheels are satisfactory, and the grinding ratio is quite high, but surface damage may be encountered. As a group, these materials are rated as having good grindability.

Aluminum alloys (soft) grind with quite low power consumption, but they tend to load the wheel quickly. Wheels with a very oven structure are needed. Grinding ratios are good. Silicon-carbide grit works well, and belt grinding outperforms wheel grinding in many cases.

(13) SAFETY IN THE USE OF ABRASIVE WHEELS-2

2014-06-24T07:41:31+00:00

SAFETY IN THE USE OF ABRASIVE WHEELS

Introduction

Abrasive wheels are extensively used in industries for various purposes. The use of abrasive wheels in an unsafe way often causes accidents leading to personal injuries and/or damage to properties. The main dangers are —

(12) Safety Guide for Grinding Wheel Users-1

2014-06-23T15:38:37+00:00

Safety Guide for Grinding Wheel Users

▲WARNING

Improper use may cause grinding wheel breakage and serious injury. Comply with ANSI B7.1，OSHA and Safety Guide furnished with package.

(11) Grinding Wheel Background

2014-06-23T14:12:00+00:00

Grinding Wheel Background

Grinding wheels are made of natural or synthetic abrasive minerals bonded together in a matrix to form a wheel. While such tools may be familiar to those with home workshops, the general public may not be aware of them because most have been developed and used by the manufacturing industry. In this sector, grinding wheels have been important for more than 150 years.

(10) A Wide Variety of Grinding

2014-06-23T13:32:33+00:00

A Wide Variety of Grinding

Grinding is a large and diverse area of manufacturing and toolmaking. It can produce very fine finishes and very accurate dimensions; yet in mass production contexts it can also rough out large volumes of metal quite rapidly.

It is usually better suited to the machining of very hard materials than is "regular" machining (that is, cutting larger chips with cutting tools such as tool bits or milling cutters), and until recent decades it was the only practical way to machine such materials

(9) Grinding Wheels and Operations

2014-06-23T12:44:42+00:00

Grinding Wheels and Operations

Grinding or abrasive machining is the process of removing metal in the form of minute chips by the action of irregularly shaped abrasive particles. These particles may be in bonded wheels, coated belts, or simply loose.

(8) Grinding Wheel: Definitions & Related Knowledge

2012-03-30T17:31:36+00:00

Grinding Wheel

Definition: The product is made of the combination of mixed abrasive and binder. After compaction, drying and calcination, it will become loose coils, round-shaped and other shapes of abrasive tools.

The grinding wheel is a round bonded abrasive tool made of abrasive and resin binder with a central through-hole. The grinding wheel is the most frequently and widely used tool among the abrasive products. Its high-speed rotation can work on metal or non-metallic workpieces with round, flat, and a variety of surface for rough grinding, semi-fine grinding, grooving and cutting.

The grinding wheel is the most important type among the abrasive products. It has binder added into the abrasives to make a porous body after compaction, drying and calcination.

Due to the differences among abrasive, binder and manufacturing process, the properties of grinding wheel varied a lot, so that the quality, production and economical efficiency of abrasive designing are greatly influenced. The property of abrasive wheel is mainly decided by many factors such as abrasive, grain size, binder, hardness, pattern, shape and dimensions.

Category: The grinding wheels can be classified into average grinding wheels (corundum, carborundum and so on), natural abrasive and extra-hard grinding wheels (diamond, cubic boron nitride and so on) according to the abrasive types;
And straight-type wheels, tapered wheels, cylinder wheels, cup wheels and saucer wheels according to the shape;
And ceramic wheels, resin wheels, rubber wheels and metal wheels according to the binder.

The characteristic parameters of grinding wheel mainly include abrasive, viscosity, hardness, binder, shape, dimension and so on. Since the grinding wheel always works in high speed, a rotating test (ensure that the grinding wheel will not split under high rotating speed) and static balancing test (prevent machine vibration when it starts) are required before using. After a period of functioning, the grinding wheel needs repair and maintainance to restore its grinding properties and correct physical shape.

Property: Grinding wheel is a round bonded abrasive tool with a hole in the center, which is made of abrasives and binder. The properties of grinding wheel are decided by the abrasive, grain size, hardness, binder, shape and dimensions.

[Followings are in Chinese Version]

砂轮是用磨料和结合剂混合经压坯、干燥、焙烧而制成的，疏松的盘状、轮状等各种形状的磨具。

砂轮是用磨料和结合剂树脂等制成的中央有通孔的圆形固结磨具。砂轮是磨具中用量最大、使用面最广的一种，使用时高速旋转，可对金属或非金属工件的外圆、内圆、平面和各种型面等进行粗磨、半精磨和精磨以及开槽和切断等。

砂轮是磨削加工中最主要的一类磨具。砂轮是在磨料中加入结合剂，经压坯、干燥和焙烧而制成的多孔体。

由于磨料、结合剂及制造工艺不同，砂轮的特性差别很大，因此对磨削的加工质量、生产率和经济性有着重要影响。砂轮的特性主要是由磨料、粒度、结合剂、硬度、组织、形状和尺寸等因素决定。

砂轮种类繁多。按所用磨料可分为普通磨料（刚玉和碳化硅等）砂轮和天然磨料超硬磨料和（金刚石和立方氮化硼等）砂轮；按形状可分为平形砂轮、斜边砂轮、筒形砂轮、杯形砂轮、碟形砂轮等；按结合剂可分为陶瓷砂轮、树脂砂轮、橡胶砂轮、金属砂轮等。

砂轮的特性参数主要有磨料、粘度、硬度、结合剂、形状、尺寸等。
由于砂轮通常在高速下工作，因而使用前应进行回转试验（保证砂轮在最高工作转速下，不会破裂）和静平衡试验（防止工作时引起机床振动）。砂轮在工作一段时间后，应进行修整以恢复磨削性能和正确的几何形状。

属性: 砂轮是用磨料和结合剂等制成的中央有通孔的圆形固结磨具。砂轮的特性由磨料、粒度、硬度、结合剂、形状及尺寸等因素来决定。

(7) Grinding Wheel Specifications: Features

2012-03-19T23:31:56+00:00

Features

	Features:
	Open Structure / Low Concentration		Bonded Abrasives - Open Structure Coated Abrasives - Open Coat Superabrasives - Low Concentration
	Closed Structure / High Concentration		Bonded Abrasives - Dense Structure Coated Abrasives - Closed Coat Superabrasives - High Concentration
	Angle / Double Bevel (E Face)		Abrasive wheel face having a pointed, "Vee" or double beveled shape for threading or similar applications.
	Radius Face (F Face)		Radius face wheels have a face that is rounded such as type 1F1 shapes.
	Tapered / Fluting (V, B Face)		Tapered face wheels have a face that is angled back such as type 1V1P shapes. Tapered face wheels are used for fluting applications.
	Specialty / Other		Other specialty, proprietary or patented features.

(6) Grinding Wheel Specifications: Mounting

2012-03-19T23:31:05+00:00

Mounting

	Mounting:
	Bore / Center Mount		Central hole or bore for mandrel, arbor, spindle or shaft mounting.
	Integral Mandrel (Mounted)		Abrasive tool is supplied as mounted onto an integral mandrel, pin, arbor or shaft.
	Plate Mounted		Abrasive wheel is mounted on a
	Quick Change		Abrasive product or disc designed for mounting using a quick change mechanism such as Norton's SpeedLoc^TM.
	Quill Mount		Grinding wheel designed for mounting using a quill.
	Specialty / Other		Other specialty, proprietary or patented mounting method.

(5) Grinding Wheel Specifications: Bond Type

2012-03-19T23:30:12+00:00

Bond Type

	Bond Type:
	Metal		Metal bond between the abrasive grains and between the grains a metal substrate. Metal bond systems are used mainly for superabrasive or tungsten carbide grit products. Three metal bond types are sintered, MSL and electroplated metal bond systems. Sintered metal bond systems are used when a thicker layer of superabrasive is required. Metal single layer (MSL) wheels consists of a specialized braze layer that forms a single layer of superabrasive and bond. The electroplated bond system is used to produce fine grit superabrasive products.
	Resin / Plastic		Bonded abrasive product with a resin, resinoid or plastic bond system between the abrasive grains.
	Rubber		Bonded abrasive product with a rubber or elastomer bond system between the abrasive grains.
	Shellac		Bonded abrasive product with a shellac bond system between the abrasive grains.
	Silicate / Oxychloride		Bonded abrasive product with a bond system using a silicate, magnesium oxychloride, magnesite or Sorel cement. These low strength bonds keep heat generation to a minimum, but may lack the life and durability of vitrified or resin bonded wheels. The chloride in the oxychloride may provide a grinding aid action.
	Vitrified		Bonded abrasive product with a vitrified or glass bond system between the abrasive grains.
	Other		Other specialty, proprietary or patented bond type.

(4) Grinding Wheel Specifications: Applications

2012-03-19T23:27:28+00:00

Applications

	Material Removal / Roughing (Coarse Grits)		Typically coarse grit abrasive products designed for heavy cutting or stock removal applications with rougher commercial finish compared to finer grit wheels. Vitrified or bonded abrasive wheels with 46 grit and coarser grain and 100S grit superabrasive wheels would fall into this category.
	Intermediate Cut & Finish (Medium Grits)		Medium or medium fine grit products are typically used for moderate stock removal combined with a better finish compared to coarser grits. Vitrified or bonded abrasive wheels with in the 54 to 80 grit grain size and 120 grit superabrasive wheels would fall into this category.
	Finishing / Light Cutting (Fine Grits)		Fine grit abrasive products designed or suitable finishing with light cutting or stock removal. Vitrified or bonded abrasive wheels with in the 100 to 120 grit grain size and 150 grit superabrasive wheels would fall into this category.
	Corner Holding / Finish Generation (Very Fine Grits)		Very fine to ultrafine abrasive products are used to improve finish and provide good corner holding characteristics. Ultrafine grit may be used for honing type applications. Vitrified or bonded abrasive wheels with 150 grit or finer grain and 180 grit superabrasive wheels would fall into this category.
	Cleaning / Surface Prep		Abrasive products such as non-woven wheels suitable for cleaning, stripping coatings, descaling, deburring or other surface preparation applications.
	Bench / Pedestal		Abrasive product designed for use on bench or back stand grinders or sanders with offhand (handheld) presentation of the parts to the abrasive.
	Cylindrical / Centerless		Grinding between centers of shafts, threaded shafts, large rolls, cams or similar components.
	Dry Grinding		Abrasive products designed or suitable for dry grinding applications.
	Form / Gear Grinding		Form, profile, gear, and other processes where the surface of the grinding wheel is shaped by dressing to create a specific profile. By dressing an inverse profile of the desired component surface on to a grinding wheel, complex sequencing of multiple steps can be avoided. Form grinding is also possible with coated abrasives and nonwoven products using specialized accessories.
	Internal / Bores		Internal grinding utilizes smaller diameter wheels or abrasive products for grinding or finishing the surface on the inner diameter of a part.
	Portable Grinder / Handheld		Abrasive product designed for use on portable or handheld grinders or sanders such as weld grinding on a large fabrication.
	Surface / Creepfeed Grinding		Abrasive products designed or suitable for Blanchard, surface or creepfeed grinding applications.
	Toolroom / Sharpening		Abrasive products designed or suitable for toolroom or precision grinding applications
	Wet Grinding		Waterproof abrasive products designed or suitable for grinding using a water or water-oil coolant mixture.
	Specialty / Other		Abrasive products designed or suitable for other specialty, proprietary or patented applications.

	Product / Materials Abraded:
	Metalworking		Abrasive products designed for metal grinding or finishing applications.
	Automotive		Abrasive products designed or suitable for automotive applications such as part or weld grinding and paint sanding.
	Ceramics / Glass		Abrasive products designed or suitable for ceramics and glass grinding or finishing.
	MRO / Construction		Abrasive products designed or suitable for cutting, grinding or finishing in maintenance & repair operations (MRO) such as the grinding of repair welds.
	Ophthalmic / Optical		Abrasive products designed or suitable for cutting, grinding or finishing applications in optical lens or component fabrication as well as for eyeglass or ophthalmic production.
	Plastics / Composites		Abrasive products designed or suitable for cutting, grinding or finishing plastics or composite materials.
	Semiconductors / Electronics		Abrasives wheels and blades designed for semiconductors or electronics such as back grinding, finishing, CMP pad dressing, IC die cutting, wafer slicing or other electronics applications.
	Specialty / Other		Abrasive products designed or suitable for cutting, grinding or finishing other unlisted specialty or proprietary materials.

	Rotary Speed:		The maximum rotary speed or speed range recommended by the supplier.

(3) Grinding Wheel Specifications: Grit Size

2012-03-19T23:26:12+00:00

Grit Size

	Grit / Micron Size:		Applies to products using abrasive grains held in a matrix or bonded to a surface such as coated abrasives, MSL superabrasives, vitrified grinding wheels, dressing sticks, honing stones or grit dressers. Grit sizes are based on ANSI, FEPA, JIS or proprietary grading system standards. Grading system standards define a grit size through specified upper and lower limits at certain points in the size distribution.

	Grading / Grit System:
	ANSI - Bonded		American or U.S. grading or grit size standards for abrasive grains used in bonded abrasives or grinding wheels.
	FEPA - F		European grading or grit size standards for abrasive grains used in bonded abrasives or grinding wheels.
	JIS		Japanese grading or grit size standards for abrasive grains.
	Micron Graded		Very fine abrasive grain graded to micron size ranges usually based an average particle size.
	Specialty / Other		Other unlisted, proprietary, or specialized grading or grit system.

(2) Grinding Wheel Specifications: Abrasive Grain Type

2012-03-19T23:20:32+00:00

Abrasive Grain Type

	Abrasive Grain Type:
	Aluminum Oxide		Aluminum oxide is the most common industrial mineral in use today. Fused aluminum oxide is produced synthetically by melting bauxite and additive in an arc furnace to form a fused aluminum oxide ingots, which are later crushed and sized. Fused aluminum oxide is also produced synthetically by chemically purifying The various types of fused aluminum oxides are distinguished by the levels of chemical impurities remaining in the fused mineral. Titanium and chromium oxides are typical additives. Other techniques to make industrial abrasive start with treating bauxite ore with a sol gel process to create alumina that is sintered to produce with an extremely fine crystalline structure typical of the sol gel or Seeded Gel products available by Saint Gobain Abrasives. Fused aluminum oxide is available in several variations depending on composition and processing such as white (high purity), brown or regular (titanium oxide modified) and pink (chromium oxide additions). Titanium oxide additions can toughen the abrasive and enable heat treating process, which changes brown aluminum oxide to a blue colored grain as TiO₂ precipitates form. Aluminum oxide abrasives are also produced with chemical precursors and precipitation, calcination and/or sintering processes. Calcined or platelet aluminas as used in fine grit or polishing applications. Sol-gel aluminum oxide is produced in using chemical ceramic technology, but this abrasive has very high performance and is usually referred to as Ceramic abrasive grain to distinguish the grain from lower performing fused aluminum oxide. Aluminum oxide occurs naturally in the form of the mineral corundum, but the mineral is not used as a commercial abrasive except as a component of emery.
	Ceramic (e.g., Norton SG®, Norton Quantum®)		Ceramic abrasives typically consist of aluminum oxide with or without additional modifiers produced using a sol-gel and sintering process. The ceramic processing route results in a hard, dense abrasive with an extremely fine crystal size and outstanding grinding performance on a variety of workpiece materials. Norton SG® and Norton Quantum® are examples of ceramic alumina grain manufactured by the Saint-Gobain Group. The patented alumina seeding process used in manufacturing Norton SG® abrasive grain produces a sub-micron crystal structure resulting in superior performance.
	Silicon Carbide		Silicon carbide is a synthetic abrasive first developed in the late 1800s. SiC is harder than aluminum oxide, but more friable than fused aluminum oxide grains. Silicon carbide is typically applied to nonferrous applications (brass, aluminum, titanium). The high solubility of carbon and silicon in iron would result in a reaction of silicon carbide with the iron base alloy and poor grinding performance. Levels and types of impurities distinguish the green and black forms of silicon carbide. The sharp and easily fractured abrasive grains for abrading other non-metals such as the stone, glass, wood, and leather. SiC, like diamond, is susceptible to oxidation at higher temperatures.
	Zirconia (e.g., Norzon®)		Alumina-zirconia abrasive grain consists of a fused alloy of aluminum oxide and zirconium oxide. NorZon® is widely used variation proprietary to Norton Company, which consisting of a fused and quenched eutectic mixture of aluminum oxide and zirconium oxide. The resulting fine structure and higher hardness contributes to improved grinding performance on stainless steel, titanium and other exotic metals.
	Superabrasive - Diamond		Synthetic diamond is produced synthetically in a high temperature, high pressure process anvil press. Diamond is superabrasive grain with the highest known hardness and a cubic crystal structure. Diamond is used for grinding nonferrous metals, ceramics, glass, stone, and building materials. Diamond is not useful in grinding steel or ferrous alloys because carbon or diamond readily dissolves or reacts with iron. Diamond pastes are useful in ferrous polishing or lapping applications where heat and reactivity are not a factor. Diamond is susceptible to oxidation at higher temperatures
	Superabrasive - CBN		Cubic boron nitride (CBN) is superabrasive grain with hardness second to diamond and a cubic crystal structure. CBN provide super grinding performance on carbon and alloy steel. Diamond is not useful in grinding steel or ferrous alloys because carbon or diamond readily dissolves or reacts with iron. CBN is produced synthetically in a high temperature, high pressure process anvil press a process similar to synthetic diamond production.
	Tungsten Carbide		Crushed tungsten carbide grit is utilized in metal bonded products for abrasion of tough materials such as composites, fiberglass, reinforced plastics, rubber and other specialized materials.
	Other		Other specialty, proprietary or patented abrasive grain, grit or abrasive material.

	Metal Clad / Armored?		Abrasive grain with a metal layer or coating. Certain superabrasive products utilize metal clad grain to dissipate heat or enhance bonding.

(1) Grinding Wheel Specifications: Type & Dimensions

2012-03-19T23:17:14+00:00

Type & Dimensions

	Type:
	Straight Wheel		Grinding wheels consist of abrasive grains bonded together by a matrix of resins, epoxy, rubber, metal, and vitrified glass materials. Straight wheels have a simple, flat disc shape without any recesses, flaring or cups. ANSI B74.2 Type 1 wheels fall under this group. Type 1A1, 1A8 are designations for straight superabrasive wheels with a straight face and no recess. 1A1R wheels are recessed for cut-off or slot cutting applications. 1A8, 1B1, 1E1, 1EE1, 1F1, 1FF1, 1V1, 1V1P are straight superabrasive wheels with modified faces (beveled, included angle or radius).
	Blank / Custom		Blank or custom wheels are designed for customization to a user's shape requirements.
	Cone / Plug		Small bonded abrasives wheel with a cone, cylinder or bullet shape that is mounted on a pin or mandrel for portable grinder applications. ANSI B74.2 Types 16, 17, 17R, 18, 18R, and 19. Type 16 - Cone wheels with a curved side and a nose radius · Type 17, 17R - Cone wheels with straight sides and optionally a nose radius · Type 18, 18R - Plug wheels with a cylindrical shape and either a square or curved grinding end · Type 19 - Combination cone and plug shaped wheels
	Cylinder		Cylinder wheels are long wheels with a simple, can shape without any recesses or cups. The length of the wheel is equal or greater than the thickness of the wheel. ANSI B74.2 Type 2 wheels fall under this group. Cylinder wheels are mounted (bolted or cemented) to a backing plate, which drives the wheel.
	Depressed Center		Grinding wheels with a depressed center, which helps keep the mounting hardware out of the grinding process. ANSI type 27, 28 and 29 wheels fall under this category. ANSI type 27 wheels have a flat configuration with a depressed center. ANSI type 29 wheels fold back away from the workpiece and wheel center while ANSI type 28 wheels project out in front of the wheel center toward the workpiece. Depressed center wheels are applied is rough offhand grinding or snagging of castings, weld beads, flash or parting lines or defects in metal parts.
	Dish Wheel		Wheels with a dish or saucer shape such as ANSI type 12 wheels. Types 12V9, 4A2P, 12A2 and 15V9 are examples of superabrasive dish shapes.
	Flaring Cup		Cups have a cup or bowl shape. Type 11 wheels are often called “flaring cups” since the sides flare out. Types 11V9, 11A2 and 12A2 are examples of superabrasive flaring cup shapes.
	Mounted Point / Abrasive Burr		Very small bonded abrasives or superabrasive wheels with a round ball, point, cone, cylinder or bullet shape that are mounted on a pin or mandrel for portable die grinder and deburring applications. Types DW, IG, IGJ, IGA, IGI and IGR are examples of superabrasive mounted point shapes.
	Recessed / Relieved		Recessed wheels having an ANSI 5 or 11 shape fall under this category. Type 5 wheels are only recessed on one side. Type 7 wheels are recessed on both sides.
	Ring / Disc Wheel		Ring wheels have a donut or toroid shape. Ring or disc grinding wheels are mounted (bolted or cemented) to a backing plate, which drives the wheel. Superabrasive type 2A2 wheels fall into this category. Conventional bonded abrasive type 35, 36 and 37 fit into this category.
	Straight Cup		Cups have a cup, bowl or double cup shape. ANSI type 6 wheel are referred to as straight cups, since they have a cylindrical configuration. Types 6A2, 6A9, 6A2C and 6A2H are examples of superabrasive straight cup shapes. ANSI type 9 or superabrasive type 9A1 wheels have a double cup shape.
	Tapered Body		Tapered body wheels have a thicker cross section at the bore, which becomes thinner or tapers toward the outer diameter. ANSI Type 3 or 4 wheels fall under this group. Superabrasive types 14A1and 3A1 wheels fall into this category.
	Specialty / Other		Other specialty, proprietary or patented abrasive or abrasive product.

	Superabrasive Wheel?		Superabrasives and diamond tools consist of grinding wheels, wheel dressers, single point tools and other products utilizing diamond or cubic boron nitride (CBN) abrasive grain.

	Outer Diameter (OD):		The OD is the outer diameter of the abrasive product.

	Bore ID / Shank Diameter:		The bore is the inner diameter of the center mount of the abrasive product. The bore is used to mount or hold the abrasive on a spindle or mandrel. The shank diameter is the diameter of the integral shank, pin, shaft or mandrel on mounted points or wheels.

	Thickness:		The wheel face thickness or the overall thickness of the abrasive products such as stones, segments, hand pads, etc.

Grinding Wheel and Grinding Related Knowledge

(20) H7 Tolerance Table (Axis & Hole)

Axis Tolerance Table (ISO)

Hole Tolerance Table (ISO)

(19) Safety Operation of Grinding Wheels [3]

(18) Safety Operation of Grinding Wheels [2]

(17) Safety Operation of Grinding Wheels [1]

(16) Grinding Wheel and Its Binder

(15) Brief Introduction about Diamond & CBN Materials

(14) Grinding Methods

(13) SAFETY IN THE USE OF ABRASIVE WHEELS-2

SAFETY IN THE USE OF ABRASIVE WHEELS

(12) Safety Guide for Grinding Wheel Users-1

Safety Guide for Grinding Wheel Users

(11) Grinding Wheel Background

(10) A Wide Variety of Grinding

A Wide Variety of Grinding

(9) Grinding Wheels and Operations

Grinding Wheels and Operations

(8) Grinding Wheel: Definitions & Related Knowledge

(7) Grinding Wheel Specifications: Features

(6) Grinding Wheel Specifications: Mounting

(5) Grinding Wheel Specifications: Bond Type

(4) Grinding Wheel Specifications: Applications

(3) Grinding Wheel Specifications: Grit Size

(2) Grinding Wheel Specifications: Abrasive Grain Type

(1) Grinding Wheel Specifications: Type & Dimensions