The paper compares mechanical mill with the other kinds of smashing equipments in the producing process of filling aluminium hydrate,and points out that mechanical mill is not noly sure that the quality of aluminium hydrate is qualified,but also has advantages of high output and low consumption,so it should be used widely.

Properties of alumina filler can have a dominating effect on epoxy resin cast system, not only on viscosity of epoxy resin cast system, quantity, but on appearance, insulated property of product, dispersing of alumina in resin as well.