Step 1: Clean the board surface. Keep the board surface free of oil and dust (mainly flux from the solder left in the reflow oven process). Because this is mainly acidic material, it will affect the durability of the components and the adhesion of the three-proof paint with the board.
Step 2: Drying. To clean the cleaning agent and water are dried to ensure that the board is dry.
Step 3: Deploy the three-proof paint according to the data provided by the manufacturer of the three-proof paint to deploy the appropriate viscosity of the three-proof paint, it is recommended that the appropriate ratio to adjust the viscosity of 15-18 seconds (coated 4 # cup). Stir evenly, and then let it stand for 3-5 minutes to let the bubbles disappear completely after you can be loaded into the spray gun inside the spray. If you use a brush, it is recommended to buy a soft wool brush.
Step 4: Spraying. Three anti paint with 200 purpose screen filter and pour into the spray pot, adjust the air pressure and spray shape of the gun, the air pressure is too small three anti paint atomization is not good spray out of the paint film will have small puddles, especially when the viscosity of the paint is a little larger, similar to the surface of the orange peel (when the board has oil stains will also appear orange peel like appearance), the air pressure is too large when three anti paint sprayed on the surface will be blown away by air pressure, in the drying process will appear hanging. It is recommended to adjust the spray gun spray shape for the fan, the nozzle and the board at an angle of 45 ° evenly moving the gun so that the spray evenly sprayed on the board, spray the first gun to go back to the second gun is to make the second gun of paint mist press the first gun of paint film, and so on until all sprayed board, so as to ensure that the uniformity of the paint film will not leak spray. The speed of the spray gun can not be too fast according to the data of the three-proof paint to ensure that the film can have a thickness of at least 50 microns.
Step 5: Bake the board surface after spraying into the baking oven inside baking. According to the data provided by the paint manufacturer, set the curve baking temperature. If the paint is self-drying, if it is a vertical oven, it is recommended to bake it for 5-10 minutes after it has been left outside for 3-5 minutes in an oven not exceeding 80 degrees. If it is a tunnel oven, it is recommended to set the front area at 60 degrees, the middle area at 80 degrees and the back area at 70 degrees. If the painted surface is directly baked at high temperature, the surface paint film will dry faster than the paint inside, which is equivalent to a film wrapping the bottom layer of paint inside. When the bottom layer of paint in the drying process of the solvent needs to evaporate out is not evaporated out will be the surface of the film drum through, it will form a lot of pores and bubbles.
Step 6: Test the board. The baking oven inside the board that out to detect whether there is a leak of air bubbles, the board surface paint film is uniform and complete without bubbles, then qualified.
Baking temperature of three-proof paint
At room temperature, 10 minutes of surface drying, 24 hours curing. If you want to be faster, you can use 60 degrees temperature baking 30 minutes, can reach the curing requirements. For a good quality paint, bake at 80 degrees for half an hour to fully cure.
Post time: Dec-30-2021