Conformal coating is a specially formulated coating used to protect circuit boards and related equipment from environmental erosion. In addition to anti-mildew, anti-salt spray and anti-humid heat, it also has many functions such as dust-proof, anti-aging, insulation, etc., which plays a vital role in enhancing the reliability and service life of PCBA boards. Different coating methods are suitable for different processing scenarios, so what are the ways to coat PCBA with conformal coating?
Spraying is the main coating method of conformal coating at present, which is divided into manual spraying and machine spraying. Among them, machine spraying belongs to the automatic spraying method, which is automatically sprayed by the machine, which has the advantages of uniform spraying, high efficiency and automatic detection of spraying effect. The disadvantage is that some blocked corners cannot be sprayed, such as the position under the electronic components, and its cost is relatively high, which is not suitable for small-scale PCBA board production.
Manual spraying is also relatively common. Manual spraying of three anti-paints is mainly carried out with the help of spray guns. The advantage is that it is easy to operate, but the disadvantage is that the accuracy and uniformity are not easy to control, and it will cost a lot of time.
2. Dip Coating
Dip coating is to immerse the entire PCBA board into a container filled with conformal coating liquid. When dipping, the PCBA needs to be immersed vertically and slowly and uniformly to avoid excessive bubbles in the conformal paint. After standing for a while, the bubbles are eliminated and then slowly and uniformly take it out. The advantage is that it is easy to operate and can completely cover the entire area of the PCBA.
The disadvantages of the dip coating method are also more obvious, because the dip coating method will increase the adhesion of the conformal paint, so the amount used is relatively large, which will increase the use cost of the conformal paint. However, as the number of dip coating increases, impurity problems will inevitably occur, and the paint needs to be replaced at this time.
Compared with other coating methods of conformal coating, brushing is the simplest coating method. The operation method is to use an anti-static soft brush to dip the conformal coating on the PCBA board. The advantage of brushing is that it is easy to operate and saves paint; The disadvantage is that it is prone to defects such as uneven thickness and poor consistency. Therefore, compared with the spraying method, the brushing method is more suitable for the conformal coating and repairing of the partially uncovered conformal paint.
4. Flow Coating
There are two operating modes of flow coating: machine flow coating and manual flow coating. Manual flow coating is suitable for small batch order production, and the operation method is also very simple, that is, pouring the PCBA board directly with conformal paint. The machine flow coating is an automatic coating method, which is more suitable for large-scale order production. Compared with other conformal coating methods, the flow coating method is relatively rare.
In addition, we need to pay attention to several issues when coating PCBA conformal coating:
1. Some electronic components that cannot be coated with paint need to be covered or removed in advance;
2. The PCBA board needs to be cleaned and dried before coating; third, it is necessary to always pay attention to the thickness and uniformity of the paint surface when coating, to prevent coating defects;
3. When coating, it is necessary to pay attention to the thickness and uniformity of the paint surface at all times to prevent coating defects.
SHENZHEN HOYOGO ELECTRONIC TECHNOLOGY CO., LTD. specializes in providing overall PCBA electronics manufacturing services, including one-stop services from upstream electronic component procurement to PCB production and processing, SMT, DIP plug-in, PCBA testing and finished product assembly.