Introduction of pcba conformal coating
2023-07-28
PCBA conformal coating is also known as PCBA protective oil, PCBA waterproof glue, PCBA insulating paint, because of the
three functions of waterproof, moistureproof and dustproof on PCBA, it is called "pcba conformal coating".
What are the coating methods of PCBA conformal coating?
1.dipping: It is more economical for large equipment, but the thickness after coating will be affected by factors such as the
temperature, time, extraction speed, vertical flow time, and whether to add an air knife.
2.spraying: spraying is economical for small and medium-sized equipment. When spraying is used, just like painting, the uniformity
2.spraying: spraying is economical for small and medium-sized equipment. When spraying is used, just like painting, the uniformity
of the coating depends on the relative speed of movement, the spraying position, the spraying pressure, and whether there are higher
parts. In addition, the bottom of the part cannot be sprayed and may require additional processing.
3.brushing: It is economical for small devices. When coating, it is easy to cause uneven coating because of the skill proficiency of
3.brushing: It is economical for small devices. When coating, it is easy to cause uneven coating because of the skill proficiency of
coating, and pay attention to the problem of brushing off the hair. The bottom of the part is also more difficult to coat.
4.Selective Coating: Although coating has many benefits, it is often time-consuming and laborious, and you can also choose the
4.Selective Coating: Although coating has many benefits, it is often time-consuming and laborious, and you can also choose the
required part of the coating.
What tools do you need to apply PCBA conformal coating, paint box, rubber gloves, mask or gas mask, brush, paper, tweezers, ventilation
equipment, drying rack, oven.
What are the technical requirements for coating PCBA conformal coating?
1.Brush conformal coating protection must be tested, inspected and thoroughly cleaned before PCBA assembly.
2.The brush used should be kept clean and prohibited from being used for other operations; When painting the brush, be careful not to
drip into the parts that do not need painting; The brush should be cleaned with thinner after use.
3.The coating layer should be transparent, and evenly cover the PCB board and components, with uniform color and consistency.
4.Process steps: brushing side A → surface dry → brushing side B → room temperature curing
3.The coating layer should be transparent, and evenly cover the PCB board and components, with uniform color and consistency.
4.Process steps: brushing side A → surface dry → brushing side B → room temperature curing
5. Spraying thickness: 0.1mm-0.3mm
6. All coating operations shall be performed at a temperature of not less than 16 ° C and relative humidity less than 75%. PCB as a composite
material will absorb moisture, if not moisture, the conformal coating can not fully play a protective role, pre-drying, vacuum
drying can remove most of the moisture.
What are the process requirements for coating PCBA conformal coating?
1.Clean and bake the board to remove moisture and moisture. Before brushing, the dust, moisture and rosin on the surface of the PCBA
board must be cleaned to make the conformal coating stick well on the surface of the circuit board. Drying conditions :60°C, 30-40 minutes,
after taking out in the oven and applying while hot, the effect is better.
2.According to the size of the product and the layout of the panel components, correctly select the brush, pour the conformal coating into the
2.According to the size of the product and the layout of the panel components, correctly select the brush, pour the conformal coating into the
container, and then use the brush to stick the appropriate adhesive liquid to evenly brush the circuit board.
3.The brushing area should be larger than the area occupied by the device to ensure full coverage of the device and pad.
4.When brushing PCBA board as flat as possible, there should be no dettol after brushing, the brushing should be smooth, and there should
3.The brushing area should be larger than the area occupied by the device to ensure full coverage of the device and pad.
4.When brushing PCBA board as flat as possible, there should be no dettol after brushing, the brushing should be smooth, and there should
be no exposed part, and the thickness of the brushing is between 0.1-0.3mm.
5.After brushing, one side of the plug-in component is placed horizontally on the air drying rack for dry curing (the coating can be accelerated
5.After brushing, one side of the plug-in component is placed horizontally on the air drying rack for dry curing (the coating can be accelerated
by heating).
6.When applying tri-resistant paint to the PCB, all connected devices, sockets, switches, radiators (pieces), cooling areas, etc., are not allowed
6.When applying tri-resistant paint to the PCB, all connected devices, sockets, switches, radiators (pieces), cooling areas, etc., are not allowed
to brush tri-resistant paint, and need to use decorative paper to cover and protect when painting.
7. If a thicker coating is desired, it can be obtained by applying two thinner coats (it is required that the first coat must be completely dried before
the second coat is allowed to be applied).
What are the operation requirements for coating PCBA conformal coating?
1.The three prevention work should be carried out in a separate closed room, and the operation room must have good ventilation facilities.
2.Smoking, eating, drinking and drinking are prohibited in the operation room. Do not use alcoholic beverages before work.
3.Wear a mask or gas mask, rubber gloves, chemical protective glasses and other protective equipment during operation to avoid injury to the
body.
4.After the work is completed, the used utensils should be cleaned in time, the tools and equipment should be arranged and sassafras tested,
4.After the work is completed, the used utensils should be cleaned in time, the tools and equipment should be arranged and sassafras tested,
and the container with conformal coating covers should be tightly covered.
5.The workplace should be clean and dust-free, no dust flying, and no unrelated personnel are prohibited from entering.
6.Properly ground tools and devices, and take ESD measures.
7.Do not overlap PCBA during operation; The PCB board should be placed horizontally.
8.Before each batch of raw materials is used, small sample curing test (3-5pcs) should be done.
5.The workplace should be clean and dust-free, no dust flying, and no unrelated personnel are prohibited from entering.
6.Properly ground tools and devices, and take ESD measures.
7.Do not overlap PCBA during operation; The PCB board should be placed horizontally.
8.Before each batch of raw materials is used, small sample curing test (3-5pcs) should be done.
What are the quality requirements for coating PCBA conformal coating?
1.PCB surface can not have paint flow, dripping phenomenon, can not have semi-wetting phenomenon.
2.The conformal coating layer should be smooth, bright, thin and thick, and protect the surface of the pad, mount component or conductor.
3.The surface of the paint layer should not have orange peel shape, bubbles, pinholes, ripples.
4.Devices or components that do not need protection do not need to be brushed with conformal coating.
5.The printed board after the three defenses should be clean and tidy, and there is no damage to components.
6.There are no dirt, handprints, ripples, shrinkage holes, dust and other defects and foreign objects on the board and components, no powder,
no peeling phenomenon.
What are the storage requirements for coating PCBA conformal coating?
1.Raw materials should be stored in a cool and dry warehouse (room temperature should not exceed 30 degrees), installed with explosion-proof
ventilation system and equipment, and should be away from heat sources.
2.To be stored separately from other types of chemicals, and to have a clear material identification, do not mix storage.
3.Pay attention to fire prevention and equip with fire fighting equipment.
4.The storage warehouse shall be equipped with leak emergency equipment and reasonable containment materials (such as sand).
5.The warehouse should be ventilated to prevent the accumulation of leaking gas and cause accidents.
6.The storage container should be marked with the expiration date.
7.Storage shelves or equipment should be well grounded. Do not use equipment and tools that are prone to spark.
2.To be stored separately from other types of chemicals, and to have a clear material identification, do not mix storage.
3.Pay attention to fire prevention and equip with fire fighting equipment.
4.The storage warehouse shall be equipped with leak emergency equipment and reasonable containment materials (such as sand).
5.The warehouse should be ventilated to prevent the accumulation of leaking gas and cause accidents.
6.The storage container should be marked with the expiration date.
7.Storage shelves or equipment should be well grounded. Do not use equipment and tools that are prone to spark.
What are the precautions for coating PCBA conformal coating?
1.Conformal coating beyond the shelf life, prohibited use.
2.The storage container should be sealed after opening.
3.Do not pour the remaining conformal coating back into the original storage container, and store it separately and tightly.
4.If the working room or storage room is not opened for a long time (more than 12 hours), ventilate it for 15 minutes before entering.
5.If accidentally splashed into the glasses, immediately open the upper and lower eyelids, rinse with running water or normal saline, and then
seek medical treatment.
6.If you feel uncomfortable when brushing, leave the job site quickly to a place with fresh air, give oxygen when breathing is difficult, and then
6.If you feel uncomfortable when brushing, leave the job site quickly to a place with fresh air, give oxygen when breathing is difficult, and then
seek medical treatment.
PCBA Which components can not be coated with conformal coating?
1.High power with cooling surface or radiator assembly, power resistor, power diode, cement resistor.
2.Dip switch, adjustable resistor, buzzer, battery holder, safety holder (tube), IC holder, touch switch.
3.All types of sockets, pins, terminals and DB heads.
4.Plug-in or stick LED, digital tube.
5.Other parts and devices that cannot use insulating paint as specified in the drawings.
6.PCBA card screw holes can not be brushed with conformal coating.