How To Tell The Quality Of PCB??

Due to the fierce competition in the PCB market, PCB raw materials are also rising, so more and more PCB manufacturers in order to increase competitiveness, often use low prices to monopolize the market.

However, behind the low price is the reduction of material costs and production costs, which will make the PCB easy to crack, easy to scratch, precision unqualified and other problems, seriously affecting the weldability and reliability of the product.

Here we teach you how to judge the quality of the PCB board, so that you will not only focus on the price of the PCB, but not on the quality of the PCB.

The Ways to Judge PCB Quality

Identify the quality of the board from its appearance

1-Check the PCB ink

Good quality circuit board factories will choose big brands of ink, pay great attention to printing and baking process, so the gloss of the ink will be better. For high-quality plates, the ink thickness is thicker. The thickness of the ink is usually required to be about 20 microns, which can generally be identified by the eyes.

2-Check the silk screen text on the PCB

High quality PCB screen printing is very clear and three-dimensional. Even if you watch with a magnifying glass, you can not see the raw edge, especially some small font screen printing.

3-Check PCB pad processing

If it is a tin spray plate, you need to check whether the tin spray is smooth and whether the IC pin position is neat. If it is a sinking gold plate, see whether the gold surface is light yellow, dark yellow or bright. The yellower the gold surface, the better the gold plating process.

4-Check the BGA pad

When a good board factory deals with BGA, first of all, engineers will be very careful when optimizing the pads. Secondly, the best equipment, experienced workers made out of BGA pads, exposure alignment processing is very good.

In addition to the above 4 points, there are some other small details that can be identified, such as the smoothness of the V cut, the color of the plate, the material of the packaging, and so on.

Identify from the quality specification requirements of the PCB board itself

1.Meet electrical connection requirements.

2.?The width, thickness and distance of the line should meet the requirements 3.avoid high temperature, break or short circuit.

4.Copper surface should not be easy to oxidize, otherwise it will affect the SMT speed, and can not be used for a long time after oxidation.

5.?No other electromagnetic radiation.

6.The shape is not deformed, and the deformation error of the hole position and reference line of the circuit board should be within the allowable range.

7.High temperature, high humidity and resistance to special environments should also be considered.

8.?Mechanical properties of the surface shall meet installation requirements.

How to ensure PCB quality?

In order to ensure the quality of PCB, it is necessary to start from the following four aspects: PCB design, PCB materials, PCB processing technology, PCB quality detection.

PCB design

In the PCB design stage, the following points need to be paid attention to:

1) Circuit diagram layout is reasonable: a reasonable circuit diagram layout is conducive to PCB processing and assembly. In the layout, it is necessary to minimize the cable length, shorten the signal transmission time, and reduce the signal transmission delay and interference.

2) Avoid electromagnetic interference: the layout of the circuit diagram should minimize circuit loops and reduce electromagnetic field interference. At the same time, impedance matching is needed on the signal transmission line to reduce signal reflection and interference.

3) Avoid circuit board wiring difficulties: wiring difficulties include high-speed signal wiring, analog signal and digital signal separation, power supply and ground line processing, and so on. In the design, it is necessary to pay special attention to the processing of wiring difficulties, and do the relevant circumvention measures.

PCB material

In the selection and use of PCB materials, the following points need to be paid attention to:

1) Select the right substrate material: The selection of substrate material directly affects the performance and reliability of the PCB. Select the substrate material that meets the specifications according to the actual requirements.

2) Select excellent components: the quality of components directly affects the reliability and performance of the PCB. Components with reliable quality, accurate size and stable electrical performance should be selected.

3) Control the position, specifications and quantity of components on the PCB: in the design, the components should be arranged as centrally as possible, and the number of components should be reduced. This helps to reduce crosstalk and interference between components.

PCB processing technology

In PCB processing technology, the following points need to be paid attention to:

1) Control manufacturing process: PCB manufacturing process includes board making, molding, drilling, copper plating, covering layer, gold immersion , printing, patch, welding and other links. In each link, the process should be controlled, so that each link is stable and reliable, and the quality of the product is qualified.

2) Optimize welding process: PCB welding process is one of the key points of PCB surface mount technology. It is necessary to strictly control the welding process parameters and control the welding quality to ensure the stability and reliability of the welding process.

3) Reduce crosstalk and interference between components: Through the circuit board partition wiring, anti-ray surround and other processing, you can effectively reduce the crosstalk and interference between components.

PCB quality inspection

After the completion of PCB processing, strict quality testing is required, mainly including the following aspects:

1) Appearance inspection: check whether there are obvious scratches, scratches, cracks and other physical damage.

2) Dimensional inspection: check whether the length, width, thickness, aperture and hole spacing of the PCB meet the requirements of the specification.

3) Functional test: ensure the normal operation of the PCB through electrical performance test, resistance test and other test methods.

4) Reliability test: verify the reliability and stability of PCB through aging test, environmental test and other means.

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Above, we introduce several methods to judge PCB quality, and also explain how to ensure quality from four aspects: design, material, process and detection.?Although these details do not 100% indicate that the quality must be good, but if a board factory can control these details in place, it is enough to show that they attach importance to quality and rigorous quality management!

TDT-ele does just that, striving for excellence while continuously improving process capabilities. We can provide you with quality one-stop service, please feel free to contact us! E-mail: [email protected].

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