How to use three glue-proof PCB correctly?
Sanfang gum does not contain evaporative substances such as acetone and xylene, which is more environmentally friendly and safe. Mainly used in electronic circuits and components to form a protective film, enhance the ability of electronic circuits and components to prevent moisture, pollution, mildew, waterproof, salt spray, avoid corrosion of solder joints and conductors, can also play the role of shielding and eliminating electromagnetic interference, avoiding short circuit of lines, and improve the insulation function of circuit boards. In addition, the coated protective film is also beneficial to the wear resistance and solvent resistance of circuits and components, and can release the pressure caused by the periodic change of temperature. Suitable spraying, painting, brushing, dipping and other processes. In order to give full play to the excellent function of the three anti-paint, the operation technology is a very important link. Many of our users always feel as if they have not reached the fantastic protective effect when using the three-proof paint. In fact, a large part of the reason is that the application process of the three-proof paint, so in order to better achieve the protective effect of the three-proof paint, we need to understand the application process of the three-proof paint. Circuit board manufacturers PCB circuit board three anti adhesive technology mainly used in the following four kinds: 1. brush coating: manual operation, the use of general simple and convenient, can play an excellent coating effect on the smooth appearance; 2. spray: spray cans type products, can be easily applied to maintenance and small-scale production, spray gun is suitable for large. Rule production, but these two spraying methods require high accuracy of operation, and may produce shadows (where the lower part of the equipment is not coated with three anti-paint); 3. Immersion: immersion can ensure a complete film coating, and will not constitute material waste caused by over-spraying; 4. Equipment selective coating: coating agent It is suitable for large-scale coating, but has high requirements for coating equipment. It is most suitable for large-scale production of PCB coating.
Three anti-paint operation process requirements:
A. First of all, in order to clean and bake PCB, remove moisture and moisture, dust, moisture, oil, flux and solder paste on the surface of the object to be painted must be removed, so as to make full use of its protective effect. A thorough cleaning ensures that corrosive residues are thoroughly removed and that the three-proof paint adheres well to the exterior of the circuit board. Drying plate conditions: 60 degree C, 10-20 minutes, when removed from the oven, hot coating effect is better; B. Brush coating method, brush coating area should be larger than the area of equipment, to ensure that all covering equipment and pads; C. Brush coating when the plate as flat as possible, no drip after brushing, brush coating should be flat, also can not be exposed part, 0.1-0.3 mm is suitable. D. Before brushing and spraying, make sure that the diluted product is well mixed, and before brushing or spraying, close and place for 2 hours to avoid solvent evaporation. Using high quality natural fiber brush, gently brush and dip at room temperature. If machinery is used, the viscosity of the paint should be measured (with a viscosifier or flow cup), and the viscosity can be adjusted with a diluent. E. Place it flat on the bracket after brushing and prepare for curing. It needs heating to accelerate the curing of the coating. If the coating is uneven in appearance or contains bubbles, solidification in high temperature furnace should be placed at room temperature for more time to allow the solvent to flash out. F. When dipping, PCB components should be immersed vertically in the paint residue. Connectors and related components should not be immersed. Unless carefully concealed, PCB should be immersed for 1 minute until the bubbles disappear, and then slowly removed. The PCB surface will form a uniform film. Much of the paint residue should be allowed to flow back from the circuit board to the dipping machine or furnace. The immersion speed of electronic circuit boards or components should not be too fast to avoid excessive bubbles. G. When used again after dipping, if there is skin crust on the surface, remove the epidermis and continue to use.
UV three anti-glue:
One-component UV/moisture two-layer curing adhesive can be cured rapidly under ultraviolet irradiation. After UV curing, the shading part can also be cured by moisture and has fluorescence display function. This product is suitable for RoHS compatibility test.
1955 is a low viscosity one-component room temperature curable silicone coating adhesive. The product has the following characteristics: curing constitutes a tough and wear-resistant surface; curing at room temperature, or accelerating curing after solvent evaporation (advocating curing temperature < 60 C); UV can indicate whether the coating is complete or not. Thick-film circuit system, porous substrates and printed circuit board cover protection.
1916 single-component room temperature curable silicone gel can be cured at room temperature or accelerated by heating; low viscosity, easy to spray, dip, brush or pour; colorless and clear, solvent-free, low odor, no corrosion to PC, copper, etc; good resistance to high and low temperatures, stable at - 60 ~200 C; completely in line with the EU RoHS, REACH finger. Requirements. It is widely used in various electronic components and circuit boards. It forms a protective film on the surface, which can prevent corrosion, dust, moisture, leakage, short circuit, cold and heat shock, aging and salt spray, and prolong its service life.
The article originated from Jiangmen single-sided and double-sided circuit boards. http://www.yonghongpcb.com