1, aluminum alloy shell CNC machining electroplated tin-cobalt alloy and electroplated cobalt similar to the tone, but softer, more popular. At present, it is mostly used to replace chromium in foreign countries. Cobalt plating is not easy to roll plating, while tin-cobalt alloy plating is suitable for small parts roll plating. In addition, tin-cobalt alloy plating has excellent uniform plating ability and roll plating ability, so it can be applied to workpieces with complex shapes. If double-layer nickel is plated on the bottom layer, its corrosion resistance is no less than that of chromium plating.

In the CNC machining of aluminum alloy shells, in order to prevent surface discoloration, they should be treated by chromate impregnation, which can also improve their corrosion resistance. If tin-nickel alloy is plated on a bright substrate or bright nickel plating, a good bright surface can be obtained. When the aluminum alloy shell is CNC machined, the original state of the surface can appear if the darkened surface (pearlescent) is plated. The plating ability of the plating layer is excellent, and there is almost no leveling effect, which is suitable for plating products requiring extremely fine lines and rotary processing.

2, aluminum alloy CNC machining plating copper - tin alloy aluminum alloy shell of low tin bronze plating layer color is pink or golden yellow, fine crystallization. It has high corrosion resistance and good spinning, and is often used as a protective and decorative nickel base layer in light industry, handicraft industry, and mechanical instrumentation industry. Medium bronze coating is golden yellow in color and has good corrosion resistance. It is mainly used as the base layer of decorative chrome plating.

Aluminum alloy has higher hardness and stability in air than low tin bronze coating. Aluminum housings are CNC machined. However, due to the high tin content in the coating, the protective decorative coating of the bottom layer of chrome plating is easy to frost, which is tin, the weakness of the medium-high bronze coating - tin bronze coating has a beautiful silver-white luster, good spinning, high hardness, wear-resistant, used as a reflective instrument, instrumentation, daily commodities, such as protective and decorative surface coatings, rather than the medium-industrial silver or chrome in design.