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As we all know, any electronic product must be processed by PCBA. After the components are mounted and plugged in the PCB , normal functional testing can be carried out, and then it can be marketed. However, the production process of PCBA needs to go through a series of processes to complete the production. Today, Shenzhen PCBA solution manufacturer Jingke Rui Precision will introduce the various processes of PCBA production to you.

PCBA production process can be divided into several major processes.

PCB design and development → SMT placement processing → DIP plug-in processing → PCBA testing → three-proof coating → finished product assembly.

Firstly, PCB design and development

1.Product requirements

A program can obtain a certain profit value in the current market, or enthusiasts want to complete their own DIY design, then the corresponding product demands appear.

2.Design and development

According to the customer’s product requirements, the R & D engineers will select a PCB solution composed of the corresponding chip and external circuit to achieve the product requirements. This process is relatively long, and the content involved here will be described separately;

3.Prototype and trial production

After the initial PCB was designed , the buyer will purchase the corresponding materials according to the BOM list provided by the R&D department for the production and debugging of the product, Trial production is divided into sampling (10pcs), secondary sampling (10pcs) ,small batch trial production (50pcs ~ 100pcs) , and large batch trial production (100pcs ~ 3001pcs) , then enter the mass production stage.

Secondly, SMT chip processing

The sequence of SMT chip processing is divided into: material baking → taking solder paste → SPI → mounting → reflow soldering → AOI → repair

1、Material baking

If the chips, PCB boards, modules and special materials have been in stock for more than 3 months, they must be baked for 24 hours at a high temperature of 120°C . For the objects of not resistant to high temperature, such as MIC microphone and LED lights, baked for 24 hours at a low temperature of 60°C.

2. Use of solder paste (rewarmed → stir → use)

Because our solder paste is stored in the environment of 2~10℃ for a long time, it needs to be rewarmed before being used. After rewarming, the solder paste needs to be stirred with a mixer before it can be used for printing;

3、SPI3D inspection

After the solder paste is printed on the circuit board, the PCB will reach the SPI device through the conveyor belt, and the SPI will detect the thickness, width, length of the solder paste printing and the good condition of the tin surface;

4. Mounting

After the PCB flows to the placement machine, the machine will select the appropriate material and paste it to the corresponding tag through the set program;

5. Reflow soldering

The pcb filled with the material flows to the front of the reflow soldering, and passes through ten step temperature zones from 148°C to 252°C in turn, and securely attaches our components to the PCB board;

6.on-line AOI inspection

AOI is an automatic optical detector. Through high-definition scanning, the newly released PCB board can be inspected, can check whether the PCB board is less material, whether the material is displaced, whether the solder joints are connected with tin, whether the components have riser ,offset and so on.

7. Repair

For the problems of PCB board found on AOI or manually , it needs to be repaired by a maintenance engineer, and the repaired PCB board

and the normal off-line board will be sent to DIP plug-in.

Thirdly, DIP plug-in

The process of DIP plug-in is divided into: shaping → plug-in → wave soldering → foot cutting → tinning → board washing → quality inspection.

1.Shaping

The plug-in materials we bought are all standard materials and they are different with and the length of the pins of the materials we need ,
so we need to reshape the pins of the materials in advance, so that the length and shape of the pins are convenient for us to carry out plug-in or post-welding;

2. Plugins

Insert the sorted components according to the corresponding templates.

3. Wave soldering

The plugged board is placed on the jig and comes to the front of the wave soldering. First, the flux that is helpful for soldering will be sprayed on the bottom. When the board comes to the top of the tin furnace, the tin water in the furnace will float up and touch the pins. When the water falls, our products are welded;

4.Cutting feet

As the pre-processing materials will have some specific requirements to leave a slightly longer pins, or the pins of the incoming material itself are not convenient for processing,the pins will be trimmed to a suitable height by manual trimming.

5.Execution of tin

Our PCB board passed the furnace, there are some pins appear

hollow, pinhole, leakage, false welding and other bad phenomena, our tinsman will repair it by manual repair;.

6.Wash the board

After wave soldering, repairing and other front-end links, there will be some flux residue or other swag attached to the pin position of the PCB board, and our employees need to clean the surface;

7.Quality inspection

To check components of the PCB board, Unqualified PCB boards need to be repaired, until qualified to enter the next step.

Fourthly, PCBA test

PCBA test can be divided into ICT test, FCT test, aging test, vibration test, etc.

PCBA test is a big test. According to different products and different customer requirements, the test methods used are different. The ICT test is to test the welding of components and the on-off of the circuit, while the FCT test is to test the input and output parameters of the PCBA board to see if they meet the requirements.

Fifthly, PCBA three anti-coating

The PCBA three-proof coating process steps are:

1. 1.Paint side A
2. 2.Surface dry
3. 3.Paint side B
4. 4.Room temperature curing
5. 5.Spray thickness: spray thickness: 0.1mm—0.3mm

All coating operations should be carried out under the conditions of not lower than 16°C and relative humidity lower than 75%. There are still many PCBA three-proof coatings, especially in some environments with relatively harsh temperature and humidity. PCBA coated three-proof paint has superior insulation, moisture-proof, anti-leakage, shock-proof, dust-proof, anti-corrosion, anti-aging, anti-mildew , Prevent parts loosening and insulation and corona resistance, which can prolong the storage time of PCBA and isolate external erosion and pollution. The spray method is the most commonly used coating method in the industry.

Sixthly, Finished product assembly

Assemble the outer casing of the PCBA board that has been coated and tested, and then carry out the aging and testing of the whole machine. Products that passed the aging test without problems can be shipped. PCBA production is a chain, and any problems in the PCBA production process will have a great impact on the overall quality, and each process needs to be strictly controlled.