Zenith Aluminum & Brass Casting Foundry
China sand casting and gravity casting manufacturer

Lacquering and lacquer varnishing

Lacquering and lacquer varnishing is often used fro aluminum casting pasts after pearl shooting, polishing or plating. The lacquer on surface of the aluminum casting parts can be protective and increase the luster of polishing finish.

Retaining the nature color of the aluminum alloy will be of much modern style. But the nude aluminum casting parts will be oxidized in atmosphere, then becoming ugly dark and gray. Thus, a simple lacquering are applied to protect the aluminum casting part from oxidization in air and much importantly to retain its nature shining silver. Zenith aluminum casting offers simply lacquering service for foreign customers, which are compliant to Rosh and CE regulation.

Stove varnishing for aluminum casting parts

Stove varnishing here are referred to color lacquer painting in stove. For some decorative parts, a transparent lacquering shows more dully. Thus a large portion of aluminum casting parts like lamp cover or another light accessory are required to paint in various colors. Such parts are mostly aluminum die casting parts, painting preferable for their fine surface quality. Zenith aluminum casting as an experienced manufacturer in this field can offer stove varnishing service to meet your fancy requirement for various colors.

Stove varnishing samples by zenith aluminum casting

Stove varnishing for aluminum casting parts introduction by zenith aluminum casting

Aluminum casting parts always have grease and dust on its surface should be pre-treated before stove varnishing:

1. De-fatting

aluminum casting parts are cleaned by acid liquid to remove the oil and dirt on the surface of the aluminum casting parts. The technology is sediment. The ingredients of the liquid is mainly consist of phosphorus acid, hydrogen fluoride acid ( HF acid), nitric acid and soap pharmaceutical and some other chemical pharmaceutical.

2. Pure water washing

After degreasing, the aluminum casting parts are cleaned in pure water, to remove the acid and any other harmful chemical materials from its surface. When we use sediment technology, oil is cleaned and there is chemical reaction on the surface of the aluminum and formed closely film. Considering environment protection, now most enterprises adopt non-chromate technology. We suggest to use German Hankel Alodine 5200 liquid. This liquid PH‹7, using temperature from 5 centigrade to 50 centigrade. Replace traditional chromate technology with Ti technology, we can reduce the cost and difficulty of waste water treatment.

3. Dry and cool in air

A oven and some wind blowing machine are used to dry the water on the surface of the aluminum casting part. After the aluminum casting part goes through the oven, it will be cooled with wind to reach room temperature.

4. Precision painting

Dry and clean aluminum casing parts are then painted in particular chamber. During the operation, the coating color and layer thickness are achieved by precise control.

5. Stove varnishing

The painted aluminum casting parts gains stable physics and chemical characteristics after it goes through the oven, stoving and solidifying. The stoving oven is composed of three heating unit. The temperature of each unit can be adjusted. The stoving oven adopts circuit hot air. We can choose three kinds of heating methods: oil, gas and electricity. We set different temperature to the three units according to the kind of paint, line speed, shape of aluminum casting parts. Acrylic acid paints needs the temperature of the aluminum casting part reach 170 centigrade to 205 centigrade; Polyester paints needs the temperature of the aluminum casting part reach 185 centigrade to 220 centigrade; PVDF paints needs the temperature of the aluminum casting part reach 240 centigrade to 260 centigrade.

6. Cooling

After the aluminum casting part goes out of the stoving oven, it should be cooled. First by wind and than by water cooled roller, and reaches room temperature.