PCBA Tech - What is PCBA proofing and process?

The so-called "PCBA proofing" refers to the trial production of printed circuit boards before mass production. It is mainly used by electronic engineers to design small circuits and complete PCBA, and then carry out small-scale trial production to the factory. As far as we know, this process is "PCBA proofing" before confirming the product design and testing the product design. Detailed process of PCBA proofing:

1. Contact the manufacturer

First of all, you need to inform the PCB manufacturer of the documents, process requirements and quantity. Take Nico Electronics as an example.

2. Opening

Purpose: According to the requirements of engineering data MI, cut into small pieces to produce panels on large pieces that meet the requirements. Small sheets that meet customer requirements.

Process: large pieces - cutting board according to MI requirements - simmering board - beer loin cover board - out board

3. Drilling

Purpose: According to the engineering data, drill the required hole in the corresponding position of the plate that meets the required size.

Process flow: laminate pin - upper board - drilling - lower board - inspection and maintenance

4. Shentong

Purpose: Copper immersion is to deposit a thin layer of copper on the wall of the insulating hole through a chemical method.

Process flow: rough grinding - hanging board - automatic copper wire - lower board - dip 1% dilute sulfuric acid - thickened copper

5. Image Transmission

Goal: Graphics transfer is to transfer the image from the production film to the circuit board

Process flow: (blue oil process): Grinding-Printing the first side-drying-Printing the second side-drying-exposure-imaging-inspection; position-exposure-still image-inspection

6. Graphic plating

Purpose: Pattern electroplating is to plate copper layer and gold nickel or tin layer on the exposed copper skin or hole wall of the circuit pattern.

Process flow: upper board - degreasing - secondary water washing - slight corrosion - water washing - pickling - copper plating - water washing - pickling - tin plating - water washing - lower board

7. Peeling

Purpose: Use NaOH solution to remove the anti-plating layer and expose the non-circuit copper layer.

Process flow: water film: insert frame - soak alkali - rinse - scrub - pass machine; dry film: release plate - pass machine

8. Etching

Purpose: Etching is to etch away the copper layer of non-circuit parts by chemical reaction.

9. Green oil

Purpose: Green oil is used to transfer the pattern of the green oil film to the board to protect the circuit and prevent tin on the circuit when welding parts.

Process flow: grinding plate-printing photosensitive green oil-translation plate-exposure-shadow; grinding plate-printing the first side-baking plate-printing the second side-baking plate

10. Personality

Purpose: Provide characters as recognizable marks

Process: After the green oil is finished, let it cool, put it on the screen, and print.

11.Gold-plated fingers

Purpose: Nickel/gold plated on the fingertips of the plug, and electroplated according to the required thickness to make it harder and more wear-resistant

Process flow: upper plate - degreasing - secondary cleaning - micro-etching - secondary cleaning - pickling - copper plating - cleaning - nickel plating - cleaning - gold plating

12. Tin plating (same place process)

Purpose: Spraying is to spray a layer of lead tin on the bare copper surface that is not covered with solder mask to protect the copper surface from corrosion and oxidation and ensure good soldering performance.

Process flow: micro-etching-air drying-preheating-rosin coating-solder coating-hot air leveling-air cooling-washing and air drying

13. Shaping

Purpose: To produce the shape required by customers by stamping or CNC gongs. Organic gongs, beer board, gongs, hand scissors

Note: Data gong board and beer board have higher accuracy, followed by manual gong, which can only make some simple shapes.

14. Testing

Purpose: To pass electronic 100% testing to detect open and short circuits that are not easy to visually detect.

Process: upper mold - stripping template - test - qualified - FQC visual inspection - unqualified - repair - return inspection - OK - REJ - scrap

15. Final inspection

Purpose: Perform 100% visual inspection on the appearance of the panel, repair the minor defects, and avoid the problem and outflow of the defective panel.

Specific work flow: feed - view data - visual inspection - qualified - FQA sampling - qualified - packaging - unqualified - processing - inspection OK

Let's take a look at how to choose a PCBA manufacturer

1. First of all, look at the demand for proofing, whether PCBA processing manufacturers can really meet:

1. Look at whether the products manufactured by the manufacturer are high-end, mid-range or low-end, and which field of products are manufactured, whether the manufacturer can provide PCBA proofing requirements.

For some high-precision PCBA processing, the general proofing company cannot provide such services due to technical capabilities and equipment reasons.

2. If the manufacturer can provide it, it depends on whether the manufacturer's delivery time is fast enough!

Many PCBA proofing needs attach great importance to the short delivery period, and the faster the product can be achieved. Many companies are unable to respond quickly to the delivery time. What I said quickly refers to delivery within 24 hours. In the case of urgency, it is faster, and the delivery time can be compressed to within 8 hours.

3. There are still some small batch orders, whether the PCBA processing manufacturer will accept it.

The basic needs are met. Next, we will mainly look at four points:

2. The degree of specialization of the factory

PCBA processing is a relatively complex process, from PCB proofing to subsequent patching, plug-ins, etc., requiring coordination and cooperation of various departments. Whether the factory has the ability to process products, the degree of professionalism is especially important.

1. Whether there is professional equipment.

PCBA processing and production require very professional equipment, such as high-speed mounting equipment, multi-temperature reflow soldering, ICT online tester, AOI tester and other equipment, which are the basis for ensuring production.

2. Whether there is professional process management

In addition to professional production equipment, PCBA proofing also requires process-based management to professionally control the quality. Better circuit board service manufacturers will pass ISO9001 quality management system, IAF, IPC-A-610E electronic assembly acceptance standards and other certifications, and will guide employees' behavior through SOP job instructions and other documents. By checking the factory's data files and qualification certification, you can roughly understand the strength of the factory's quality control.

3. Is there a complete inspection process?

In addition to professional equipment and professional process management, a complete inspection process is also required. Everyone knows that proofing is a delicate task. The mounting of many electronic components, DIP and even the plug-in soldering of many pins, the whole process is complicated and the quality may be problematic. Therefore, it is necessary to check at various levels, strictly inspect quality defects, and "check for deficiencies and make up for leaks." A PCBA proofing company that values quality will be equipped with a complete inspection process: IQC incoming inspection, SPI solder paste inspection, online AOI inspection, SMT first article inspection, appearance inspection, X-ray soldering inspection, BGA device repair, QA inspection, Anti-static warehousing

3. Service consciousness

A PCBA proofing manufacturer with a good sense of service can take the initiative to take responsibility when customers encounter problems, respond quickly, and solve problems for customers. PCBA proofing manufacturers provide processing services, not real products. Therefore, the service awareness of a PCBA proofing manufacturer is very important. The service awareness of PCBA proofing manufacturers can be used to understand the company's corporate culture and the attitude of business personnel to customers through its official website.

4. Industry experience

Nowadays, the PCBA industry is in a stage where some poorly managed PCBA proofing manufacturers have closed down one after another. PCBA manufacturers with many years of industry experience have stronger comprehensive strength and more advantageous services.

Five, the price

In the market, the price of PCBA proofing is relatively transparent, some are high, and some are relatively low, but the price is not as low as possible. Some PCBA proofing manufacturers choose to purchase genuine, original brand components and implement strict quality control, which will increase the cost of processing; and some PCBA proofing manufacturers may cut corners in order to reduce prices, resulting in unstable quality and delivery quality. Very poor, many defective products. As the saying goes, you get what you pay for, we should choose a suitable cost-effective PCBA proofing manufacturer based on our own situation.