A、Properties of aluminum alloy：

Among non-ferrous metal materials, aluminum alloy is a relatively common material. Its grinding processability, mechanical and physical properties are different from metal materials such as steel and cast iron. It has the following characteristics:

1、Low hardness and strength: the highest hardness of aluminum alloy is HB110～120, and the maximum tensile strength is generally 20～30kg/cm2. Due to the low hardness, the material has poor resistance to plastic deformation or scratches, and it is easy to scratch and scratch the surface of the workpiece during grinding.

2、Plastic ductility is large, and plastic adhesion occurs during the grinding process, which blocks the surface of the grinding wheel; at the same time, the melting point of aluminum alloy is low (660～780℃). At the high temperature in the grinding zone, the metal on the surface melts and adheres to the surface of the grinding wheel. Produce hot melt adhesion and increase the blockage of the grinding wheel.

3、Large linear expansion coefficient: under the action of grinding heat, it is easy to cause deformation of the aluminum alloy workpiece, thereby affecting the grinding accuracy of the workpiece surface.

4、Low grinding efficiency: In order to overcome the thermal deformation of the aluminum alloy workpiece during the grinding process, reduce the adhesion and blockage of the grinding wheel surface, and ensure the quality of the processed surface, the number of dressing must be increased, which is about 3 times that of ordinary steel, thus reducing Grinding productivity.

B、The choice of grinding aluminum alloy wheel：

The biggest problem in the aluminum alloy grinding process is “sticky” and “clogging”

a)、Aluminum alloy superfine grinding and mirror grinding: use “PVA” grinding wheel, which is equivalent to Japanese “UB” grinding wheel. A mirror effect can be achieved. This kind of grinding wheel is also similar in structure to the ceramic grinding wheel.

b). Aluminum alloy rough grinding and semi-finishing grinding:

1. Abrasive: Use brittle and sharp black silicon carbide.

2. Bonding agent: Use ceramic bonding agent with high strength, and it is resistant to oil, acid, alkali and corrosion.

3. Granularity: Use the thicker number if the requirements are met. Rough grinding: use 36～46#; fine grinding: use 60-80; the number of coarse grains is relatively small compared with the number of abrasive particles participating in the grinding, and the grinding heat is also less, which reduces the deformation of the workpiece and the blockage of the grinding wheel;

4. Hardness: A lower hardness should be selected to keep the grinding wheel good self-sharpening. Generally use H～J hardness.

5. Organization: A looser organization should be used to contain the grinding debris, so that the coolant can enter the grinding area, enhance the cooling effect, and reduce the temperature of the grinding area. The large hole grinding wheel with loose structure should be selected, which has a better grinding effect.

C、 grinding fluid

Use grinding fluid with good cleaning performance, good lubrication performance and cooling performance. And the supply of grinding fluid should be sufficient to ensure good cleaning and cooling effects. It is recommended to use the special grinding fluid for aluminum alloy grinding produced by the manufacturer, such as Castrol’s ALUSOL series. If the conditions do not allow, diesel oil can be used as the grinding fluid, and the practical effect is still relatively ideal. But diesel oil is prone to oil mist and volatile during use. In view of this: a small amount of engine oil or carbon tetrachloride can be added to diesel.

D、grinding skills

1. The feed speed should be uniform during the grinding process, especially the lateral feed.

2. The grinding wheel is easily blocked and passivated during the aluminum grinding process, so the grinding wheel scratches and burn marks are easy to appear on the processed surface, so the grinding wheel surface needs to be lubricated: the external lubricant, oil, and paste can be appropriately added. Diesel oil can be applied to the top of the grinding wheel, but it is dirty. Can be coated with candles, industrial wax, lubricants, lubricating paste, etc. It can reduce blockage causing burns and scratches.

3. For the aluminum chips sticking to the grinding wheel, use oilstone or a sharp blade. Scrape the sticky crumbs.

4. The grinding wheel must be trimmed in time to make it rougher, but must be sharp to prevent clogging.

5. The corners of the grinding wheel can be chamfered with a grinding wheel cutter. To facilitate the timely discharge of aluminum chips.