Application of Spraying Surface Treatment

In the CNC machining industry, Weimi mainly manufactures precision milling and milling parts for metal materials according to the design drawings provided by customers, and the parts are used in various industrial OEM projects. Some CNC parts need to be painted or receive surface treatment after processing to fit the customer’s requirements – this can be done in several ways.

After the surface is treated, an oxide film is formed to protect the aluminium profile from oxidative corrosion, which can be used for a wide range of environmental conditions. For example, in the LED industry, if the lamps are often exposed to the sunlight, wind and rain, it is very easy to fade. To meet the external conditions or extend the surface effect of the products after the milling, some CNC parts will need powder spraying.

This is because, by electrostatic spraying (powder spraying), one can get a thicker coating, such as 100 to 300 um coating, with ordinary solvent coating you would need to work on the area 4 to 6 times, but with powder coating can be done once to reach this thickness. The corrosion resistance of the coating is very good, mainly used in metal surface coating.

The main features of electrostatic spraying are: manual, automatic or manual + automatic. The sprayed material is 100% solid powder, the free powder can be recycled, and the paint recycling rate can reach 98%. So it is also very environmentally friendly! Because of this, the electrostatic powder coating method is a powder coating method that is dominant in the industrial coating field.

To achieve a better surface finish, the CNC parts need to be pre-sprayed. After pre-treatment, not only is the surface free from oil, rust or dust, but it also has a uniform and rough grey phosphating film (chromium film) which will not rust easily.

Due to environmental factors, coating equipment, operator factors and pre-treatment effects, the disparity rate is 80-90%, while the powder coating itself accounts for only 10-20%. The following examples show sprayed steel processing parts, completed by Weimi:

Stoving varnish, similar to powder coating. Metal stoving varnish is an industrial lacquer, which is divided into water-based metal stoving varnish and oily metal stoving varnish. Paint spraying can also cover the film layer to protect the appearance and life of the product. Paint spraying is a way to spray paint on the surface of the product and dry it naturally.

There are other ways, such as electroplating or electrophoresis. As for which surface treatment to choose, the most important thing is to look at the use and actual needs of the metal CNC parts! For example, if the requirement for corrosion resistance is high, you can consider paint spraying; if there are requirements for a bright surface and with a metal texture, you can consider electroplating; if the overall requirements for decorative and corrosion resistance are high, you can choose electrophoresis.

It is a crucial first step to choose a quality and experienced supplier whether it is based on the structural requirements of the product itself or the choice of the appropriate surface treatment according to the place. Here, I would like to introduce you to our company – Dongguan Weimi Hardware Technology Co., Ltd.

Weimi is a factory specialized in the precision machining of CNC machine tools of turning and milling CNC parts and provides a one-stop service for customers. From raw material procurement to surface treatment, we will help customers with customer requirements.

Customers who have been clients of Weimi for many years know that we have always been very strict on quality control and pride ourselves in the products we produce.

Dongguan Weimi will carry out the following test contents for spray products:

1.Product cleaning: the internal and external visible surface parts of the product shall be clean, free from any dirt, oil stain and other dirt that may affect the appearance, and shall not have any left white trace after the finger is scratched.

2.Product appearance: check whether the product has wrinkle, shrinkage, blistering, whitening, skin cleaning, sagging, particles and other adverse phenomena, which greatly affects the appearance of the product.

3.Characteristic inspection: check the color difference (color difference meter), film thickness (film thickness meter) and glossiness of spraying according to the standard color plate.

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