Today we will talk about an essential process in the PCBA processing process -- coating three anti - paint
Why should PCBA be coated with three anti - paint?
Three anti-paint is a special formula of paint, used to protect PCBA circuit board and related equipment from environmental erosion, so as to improve and extend their service life, to ensure the use of safety and reliability, PCBA three anti-paint on PCBA with waterproof, moisture-proof, dust-proof three roles, so called "PCBA three anti-paint".
What tools do PCBA need to apply three anti - paint?
Three anti-paint, paint box, rubber gloves, mask or gas mask, brush, paper, tweezers, ventilation equipment, drying rack, oven.
What are the coating ways of PCBA three anti - paint?
1, dipping (dipping) : more economical for large equipment, but the thickness of the coating will be affected by dipping temperature, time, extraction speed, vertical flow time, whether to add air knife... And other factors.
2. spraying: spraying will be economical for small and medium-sized equipment. When using spraying, just like spray painting, coating uniformity depends on the relative speed of movement, spraying position, spraying pressure, whether there are higher parts. In addition, the bottom of the parts cannot be sprayed, which 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 coating. In addition, we should also pay attention to the problem of hair brushing off. The bottom of the parts is also more difficult to coat.
4. Selective Coating: although it has many advantages, coating is often time-consuming and laborious. It can also choose the parts that need coating.
What are the technical requirements of PCBA coating three anti - paint?
1. Brush three anti-paint protection must be tested, inspected and thoroughly cleaned before PCBA assembly.
2, the use of brush to keep clean, prohibited 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 diluent after use.
3, the coating layer should be transparent, and evenly cover PCB board and components, color and consistency is uniform.
4, the process steps are: brushing side A → surface dry → brushing side B → room temperature curing
5, spraying thickness: spraying thickness is 0.1mm - 0.3mm
6. All coating operations shall be carried out under the conditions of not less than 16℃ and relative humidity less than 75%. As a composite material, PCB will absorb moisture. If the moisture is not removed, the three anti-corrosion paint cannot play a full protective role. Pre-drying and vacuum drying can remove most moisture.
What are the process requirements of PCBA coating three anti - 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 cleaned to make the three anti-paint stick well on the surface of the circuit board. Drying plate conditions: 60°C, 30-40 minutes, after taking out in the oven while hot coating effect is better.
2, according to the size of the product and the layout of the board components, correctly choose to use the brush, pour the three anti-paint into the container, and then use the brush to stick appropriate adhesive liquid to evenly brush the circuit board.
3. The brushing area should be larger than the area of the device to ensure full coverage of the device and pad.
4. When brushing, PCBA board should be laid flat as far as possible. After brushing, there should be no dettol, the brushing should be smooth, and there should be no exposed part.
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 three-proof paint to PCB, all connecting and connecting devices, sockets, switches, radiators (pieces), cooling areas, etc. (do not apply three-proof paint components, see remarks) are not allowed to brush three-proof paint, and should be covered with beautiful paper protection.
7. If a thicker coat 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).
What are the operation requirements of PCBA coating three anti - paint?
1, the three prevention work should be carried out in a separate closed room, the operation room must have good ventilation facilities.
2. Smoking, eating 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 finished, clean the used utensils in time, arrange, Sassafras test tools and equipment, and cover the container with three anti-paint tightly.
5, the workplace should be clean and dust-free, no dust flying, and irrelevant personnel are prohibited to enter.
6. Fully ground tools and equipment, and take ESD preventive measures.
7. Do not overlap PCBA during operation; The PCB board should be placed horizontally.
8, each batch of raw materials before use, should do the small sample curing test (3 -- 5PCS).
What are the quality requirements of PCBA coating three anti - paint?
1, PCB surface can not have paint flow, dripping phenomenon, can not have semi-wetting phenomenon.
2, three anti-paint layer should be smooth, bright, uniform thickness, the welding pad, paste components or conductor surface protection.
3, paint layer surface can not have orange peel shape, bubble, pinhole, ripple phenomenon.
4, do not need to protect the devices or components do not need to brush with three anti-paint.
5. The printed board after the three defenses should be clean and tidy, without damage to components.
6. There are no dirt, handprints, ripples, shrinkage holes, dust and other defects and foreign objects on the board surface and components, no powder, no peeling phenomenon.
What are the storage requirements of PCBA coating three anti - paint?
1, raw materials should be stored in a cool, 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 kinds of chemicals, and to have clear material identification, do not mix storage.
3, pay attention to fire prevention, and equipped with fire equipment.
4. The storage warehouse shall be equipped with leak emergency equipment and reasonable holding materials (such as sand).
5. The warehouse should be kept 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 properly connected. Devices and tools that are easy to generate sparks are prohibited.
What are the precautions of PCBA coating three anti - paint?
1, three anti-paint over the shelf life, prohibited use.
2. Storage container should be sealed after opening.
3, do not use the remaining three anti-paint back to the original storage container, to separate sealed storage.
4. If the working room or storage room is not opened for a long time (more than 12 hours), it should be ventilated for 15 minutes before entering.
5, accidentally splashed into the glasses should immediately open the upper and lower eyelids, rinse with flowing water or normal saline, and then medical treatment.
6. If you feel uncomfortable while brushing, leave the site quickly to a place with fresh air. If breathing is difficult, give oxygen and then seek medical treatment.
Which components of PCBA cannot be coated with three-proof paint?
1, high power with cooling surface or radiator components, power resistance, power diode, cement resistance.
2, dip switch, adjustable resistance, buzzer, battery holder, safety seat (tube), IC seat, touch switch.
3. All types of sockets, pins, wiring terminals and DB heads.
4, plug or stick type LED, digital tube.
5. Other parts and devices that cannot use insulating paint according to the drawings.
6, PCBA board card screw hole can not brush coated with three anti-paint.
2. How to choose PCBA processing manufacturers
Friends from all industries, good afternoon! I am a small editor of PCBA processing plant. Today, what I want to share with my friends is how to choose PCBA processing manufacturers as PCBA purchasers.
Now PCBA processing outsourcing has gradually come into our sight, but for customers, how to find high-quality PCBA processing manufacturers may also become a problem, in the sight of many manufacturers, many people do not know how to make a choice, in fact, you should consider from the following aspects, Finally choose to let themselves at ease with the manufacturer.
First, whether there is a standard procedure flow; In the selection of PCBA processing manufacturers, we should first understand whether the other side has a standardized process, which is itself a rigorous production technology, so for the whole process should also pay attention to, if there is no detailed understanding, of course, will affect the quality of products. For example, in the normal production process, the first thing is to have PFEMA analysis, and then the engineering staff to make strict operating standards, and then into the production stage, of course, this step has some series of quality systems, such as ISO9001,ISO13485 and IATF16949 and other quality systems.
Second, whether the standard is implemented; If you really want to find a more professional PCBA processing manufacturers, we should first look at whether the other side has the implementation of standards, in fact, any enterprise for the corresponding content should be paid attention to, the processing standard itself is a big guarantee after the product is made, if there is no way to meet the corresponding standards, Of course, there is no way to have better qualified products, so if we choose the processing manufacturers can reflect the advantages from all aspects, of course, can bring us good results, generally in the selection of production in the process of each link can not be ignored, especially the content of this small details can not be missed.
Third, the delivery time; Many manufacturers choose PCBA processing manufacturers, perhaps in order to reasonably save their own problems in the process of daily operation, for example, sometimes it may be because of the time, so they will choose processing manufacturers to help themselves, so in the choice of time must value the strength of the other side, if the other side does not have the strength of this aspect, Of course, can not meet the delivery within the specified time, and in the delivery process must also see whether the quality can be guaranteed, these are very important, if you can complete the work within the specified time, but there is no better quality, of course, will have a certain impact, so in the usual selection process, these small details themselves should be paid attention to.
Today, kingford shares here. For more information about PCBA processing industry, please lock in the new electronic news column. Xiaobian will share the professional knowledge of the industry for you here. At the same time, if you also have SMT patch processing, and PCBA processing needs, welcome to call our professional customer service hotline, we will serve you wholeheartedly.