First, the performance of aluminum alloy

Aluminum alloys are common materials used in nonferrous materials.Its grinding, mechanical and physical properties are different from those of steel, cast iron and other metal materials. It has the following characteristics:

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

2. High ductility leads to plastic adhesion during grinding and blocks the surface of grinding wheel; At the same time, the melting point of aluminum alloy is low (660 ~ 780℃). Under the high temperature of grinding zone, the surface of metal melts and adheres to the surface of grinding wheel, resulting in hot-melt adhesion and increasing the blockage of grinding wheel.

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

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

Second. Selection of aluminum alloy grinding wheel:

The biggest problem in the grinding of aluminum alloy is "adhesion" and "blockage".

A. Super fine grinding and mirror grinding of aluminum alloy: "PVA" grinding wheel is used, which is equivalent to "UB" grinding wheel in Japan. You can get a mirror effect. The wheel is also similar in structure to a ceramic wheel.

B. Coarse and semi-fine grinding of aluminum alloy:

1, abrasive: the use of brittle and sharp black silicon carbide.

2. Bonding agent: Ceramic bonding agent with high strength and resistance to oil, acid, alkali and corrosion.

3. Granularity: coarse code is used when the requirements are met.Coarse grinding: 36 ~ 46#; Fine grinding: adopt 60-80; The coarse-grain size is less than the number of grinding grains and less grinding heat, which reduces the deformation of the workpiece and blockage of the grinding wheel.

4. Hardness: Lower hardness should be selected to keep good self-sharpness of grinding wheel. Grade H ~ J hardness is generally selected.

5. Structure: Loose structure should be used to accommodate grinding chips so as to allow coolant to enter the grinding zone, enhance cooling effect and reduce grinding zone temperature.The large pore wheel with loose structure should be selected for better grinding effect.

Three. Grinding fluid. Adopt grinding fluid with good cleaning, lubrication and cooling properties

Four, 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. 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.