Nine requirements for the application of three proof paint

PCBA three proof paint is a common protective coating for circuit boards, which is an essential anti-aging protective paint for electronic equipment circuit boards working in harsh environments. It is also known as three proof glue, circuit board covering glue, PCBA protective oil, PCBA waterproof glue, PCBA insulation paint, because it has waterproof, moisture-proof, shockproof, anti-corrosion, dustproof, and anti-static effects on PCBA. The conventional requirement is PCBA waterproof, moisture-proof, and corrosion-proof three proof, so it is called "PCBA three proof paint", which is actually a multi proof paint.

Nine requirements for the application of three proof paint

Because the three proof paint is coated on the surface of circuit boards in a paint like form, more people call it three proof paint, and upon closer examination of its composition, there are actually many types of three proof paint, such as polyurethane, acrylic, and silicon. What are the requirements for applying three proof paint? Let's go into detail below:

1、 What are the coating methods for PCBA three proof paint?

1. Dipping: It is more economical for large equipment, but the thickness after coating is affected by factors such as the temperature, time, extraction speed, sagging time, whether to add an air knife, etc. Sometimes it is also affected by the characteristics of some components and cannot be impregnated.

2. Spraying: It is more economical for small and medium-sized equipment. When using spray painting, just like spray painting, the uniformity of the coating depends on the relative movement speed, spray position, spray pressure, and whether there are higher parts. Additionally, the bottom of the parts cannot be sprayed and may require additional treatment.

3. Brushing: It is more economical for small devices. When coating, it is easy to cause uneven coating due to the proficiency of the coating technique. In addition, it is also important to pay attention to the problem of brush shedding. The bottom of the parts is also difficult to apply.

4. Selective Coating: Although there are many benefits to coating, it is often time-consuming and labor-intensive. You can also choose to apply at the required positions. Some three proof paint spraying machines can selectively apply through program settings, which is much more convenient than manual coating.

2、 What are the operational requirements for applying PCBA three proof paint?

1. The three prevention work should be carried out in a separate room, but it cannot be completely enclosed, and there must be good ventilation facilities.

2. Smoking, eating, and drinking are prohibited in the operation room, and alcoholic beverages should not be used before work.

3. When operating, it is necessary to wear protective equipment such as masks or gas masks, rubber gloves, chemical protective goggles, etc. to avoid harm to the body. This also depends on the selected three proof paint product. If it is a product containing benzene, special attention should be paid to protection and fire prevention. If it is a TIS-NM environmentally friendly three proof paint product, it has much higher safety and no risk of combustion.

4. After completing the work, it is necessary to clean used utensils in a timely manner, organize and wipe tools and equipment, and tightly cover the container containing the three proof paint.

5. The workplace should be clean and dust-free, with no flying dust, and unrelated personnel are prohibited from entering.

6. Tools and equipment should be fully grounded and electrostatic protection measures should be taken.

7. Do not overlap the PCBA during operation; The PCB board should be placed horizontally.

8. Before use, each batch of raw materials should undergo a small sample curing test (3-5 PCS).

3、 What tools are needed to apply PCBA three proof paint?

Three proof paint, paint box, rubber gloves, mask or gas mask, brush, American adhesive paper, tweezers, ventilation equipment, drying rack, oven.

4、 What are the process requirements for coating PCBA three proof paint?

1. Clean and dry the board to remove moisture and moisture. Before brushing, the dust, moisture, and rosin on the surface of the PCBA board must be removed to ensure that the three proof paint adheres well to the surface of the circuit board. Drying conditions: 60 ° C, 30-40 minutes, take it out in the oven and apply it while it is hot.

2. Choose the appropriate brush according to the product size and layout of the board components, pour the three proof paint into the container, and then use the brush to apply an appropriate adhesive evenly to the circuit board.

Comparison of three proof paint before and after brushing

3. The brushing area should be larger than the area occupied by the device to ensure full coverage of the device and solder pads.

4. When brushing, the PCBA board should be placed flat as much as possible, and there should be no dripping after brushing. The brushing should be smooth and there should be no exposed parts. The brushing thickness should be between 0.1-0.3mm.

5. After brushing, the plug-in components are placed horizontally on the air drying rack with one side facing upwards for surface drying and curing (heating can accelerate the coating curing).

6. When applying three proof paint to a PCB, it is not allowed to apply three proof paint to all connected plug-in devices, sockets, switches, heat sinks (chips), heat dissipation areas, etc. (please refer to the remarks for components that cannot be coated with three proof paint). During the application, it is necessary to use masking paper to cover and protect them.

7. If a thicker coating is desired, it can be obtained by applying two thinner layers (the second layer must be allowed only after the * * layer has completely dried).

5、 What are the technical requirements for coating PCBA three proof paint?

1. The three proof paint 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 tasks; When painting with a brush, be careful not to drip onto parts that do not require painting; After use, the brush should be cleaned thoroughly with diluent or other ingredients.

3. The coating layer should be transparent and evenly cover the PCB board and components, with uniform color and consistency.

4. The process steps are: painting surface A → surface drying → painting surface B → room temperature curing

5. Spraying thickness: The spraying thickness is between 0.1mm and 0.3mm

6. All coating operations should be carried out under conditions of no less than 16 ℃ and relative humidity below 75%. PCB, as a composite material, will absorb moisture. Without removing moisture, the three proof paint cannot fully protect it. Pre drying and vacuum drying can remove most of the moisture.

6、 What are the precautions for applying PCBA three proof paint?

1. Three proof paint exceeding its shelf life is prohibited from use.

2. After opening the storage container, it should be sealed and stored.

3. It is prohibited to pour the remaining three proof paint back into the original storage container and store it separately and tightly.

4. If the workspace or storage room has not been opened for a long time (more than 12 hours), it should be ventilated for 15 minutes before entering.

5. If accidentally splashed into glasses, immediately open the upper and lower eyelids, rinse with flowing water or physiological saline, and then seek medical treatment.

6. If you feel uncomfortable during brushing, you should quickly leave the work site and go to a place with fresh air. If you have difficulty breathing, give oxygen and then seek medical treatment.

7、 What are the quality requirements for coating PCBA three proof paint?

1. The surface of the PCB should not have paint flow, dripping, or semi wetting.

2. The three proof paint layer should be flat, bright, and uniform in thickness, protecting the surface of solder pads, adhesive components, or conductors.

3. The surface of the paint layer should not have orange peel, bubbles, pinholes, or ripples.

4. Devices or components that do not require protection do not need to be painted with three proof paint.

5. The printed circuit board after the three protections should be clean and tidy, without any damage to components.

6. There are no defects or foreign objects such as dirt, fingerprints, ripples, shrinkage holes, dust, etc. on the board and components, and there is no powdering or peeling phenomenon.

8、 Which PCBA components cannot be coated with three proof paint?

1. High power with heat dissipation surface or radiator components, power resistors, power diodes, cement resistors.

2. DIP switch, adjustable resistor, buzzer, battery holder, fuse holder (tube), IC holder, touch switch.

3. All types of sockets, pins, wiring terminals, and DB heads.

4. Plug in or mount light-emitting diodes, digital tubes.

5. Other parts and components that are not allowed to use insulating paint as specified in the drawings.

6. The screw holes on the PCBA board cannot be painted with three proof paint.

9、 What are the storage requirements for coating PCBA three proof paint?

1. Raw materials should be stored in a cool and dry warehouse (room temperature should not exceed 30 degrees), equipped with explosion-proof ventilation systems and equipment, and kept away from heat sources.

2. It should be stored separately from other types of chemicals and have clear material labeling to avoid mixing.

3. Pay attention to fire prevention and equip with fire-fighting equipment.

4. The storage warehouse should be equipped with emergency equipment for leaks and reasonable containment materials (such as sand).

5. The warehouse should maintain ventilation to prevent accidents caused by the accumulation of leaked gases.

6. The effective date of use should be indicated on the storage container.

7. Storage shelves or equipment should be well grounded, and the use of equipment and tools that are prone to sparks is prohibited.