Aluminum alloy has the properties of low hardness and strength, high ductility, and large linear expansion coefficient. It is most prone to blockage, scratches, strains, etc. during the grinding process. In order to avoid these phenomena, the grinding wheel and grinding fluid must be selected in the grinding process, and the grinding process and parameters must be optimized.

一、Properties of aluminum alloy

Among the 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、The 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℃). Under the high temperature of 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.

二、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、Binder: Use a ceramic bond with higher strength, and is resistant to oil, acid, alkali and corrosion.

3、Granularity: Use a 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, reducing 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 hold 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 used, which has a better grinding effect.

三、Grinding fluid:

Adopt grinding fluid with good cleaning performance, good lubrication performance and cooling performance. And the grinding fluid supply should be sufficient to ensure a good cleaning and cooling effect. It is recommended to use special grinding fluid for aluminum alloy grinding, such as Castrol’s ALUSOL series. If the conditions do not allow the use of diesel as grinding fluid, the practice effect is more ideal. But diesel oil is easy to produce oil mist and volatilize during use. Note: a small amount of oil or carbon tetrachloride can be added to diesel oil.

四、Grinding skills:

1、in the grinding process feed speed should be uniform, especially transverse feed.

2. Grinding wheel is easy to block and passivate in the grinding process of aluminum, so grinding wheel scratches and burn marks are easy to appear on the surface of the grinding wheel. Therefore, lubrication is needed when grinding wheel surface is processed: lubricating fluid, oil and paste can be appropriately added externally. You can choose the grinding wheel above the diesel oil, but dirty. You can put candles, industrial wax, lubricants, ointments, etc. Can reduce clogging caused by burns, scratches, etc.

3. For aluminum chips attached to the grinding wheel, whetstone or a sharp blade may be used. Scrape the muck.

4. The grinding wheel must be dressed in time. The dressing must be rough but sharp to prevent blockage.

5. The edge Angle of the grinding wheel can be lowered with the grinding wheel knife. Facilitate the timely discharge of aluminum chips.