Where are the OEM manufacturers in Changsha? Circuit board proofing refers to the trial production of printed circuit boards before mass production. It is mainly used in the process of small batch trial production in the factory after the electronic engineer designs the circuit board, that is, circuit board proofing. Generally, there is no specific limit to the production of printed circuit board proofing. Before the product design is confirmed and tested, it is called printed circuit board proofing by engineers.
The method of judging the quality of PCB: distinguish the quality of PCB from its appearance. Analyze and judge through three aspects; And standard rules of size and thickness. The thickness of standard circuit boards is different, and customers can measure and check according to the thickness and specifications of their products.
2. Proofreading problems
1 speed
PCB products in the market are constantly changing. In this industry, time is a very important factor. Delivery time and quality are the hard strength of the factory, and they are also favored by engineers and factories. At present, the circuit board factory generally provides expedited service, and the normal delivery time of the express factory also has 2 days. For example, in the Yangtze River Delta region, the emerging Czech Republic promised not to increase any expediting fees, and all models were expedited by default. For example, single-sided and double-sided panels, large-board proofing and small batch, less than or equal to 30 pieces, with an area of more than 1 square meter, can now be shipped 24 hours a day! It cost 2-3 square meters. The delivery time for small batches of 1-5 square meters is changed to 72 hours (originally 3-4 days), and all orders are mailed by SF Express. Another example is the old model Huaqiang, Jieduobang, Jialicheng, etc.
2 quality
It is the trial production stage of engineers before PCB product design confirmation and testing, and its quality can not be ignored. From raw materials, surveying and mapping, to production, testing and quality control, every link needs to be strictly controlled. For example, common double panels, plates generally include FR-4, aluminum substrate, CEM-1, etc., and the thickness of plates is between to.
The thickness of copper is ounces to ounces. Different materials lead to great differences in quotations. At present, the better material used by manufacturers is imported Shengyi board.
Three. price
With the development of the industry, the price of PCB proofing and small and medium batch production is declining. At present, many proofing companies, such as jetpo, cancel all proofing/small-batch negative fees, and movie fees also withdraw from the historical stage. It will be the price trend of PCB proofing in the future to complete challenging tasks at challenging prices.
Gold deposition is to wrap a thick layer of nickel-gold alloy with good electrical properties on the copper surface, which can protect PCB； for a long time; In addition, it also has the endurance to the environment that other surface treatment processes do not have. In addition, gold deposition can also prevent copper from dissolving, which will be beneficial to lead-free assembly.
3. Pavement measurement
1 in high temperature environment, the copper sheet is not easy to fall off;
2 The line thickness, line spacing and line width of the line meet the design requirements to prevent the line from heating, short circuit and open circuit;
Three. PCB has no additional electromagnetic radiation;
4. In the process of PCB proofing, special environments such as high temperature and high humidity are considered;
5 The copper surface is not easy to oxidize, which affects the installation speed and cannot be used for a long time after oxidation;
6. Ensure that the plate shape is not deformed, so as to avoid dislocation of screw holes after installation. At present, mechanical installation is adopted. The hole position of the circuit board and the deformation error of the circuit design should be within the allowable range.
Circuit board production process: drilling. Objective: According to the engineering data, drill the required hole diameter at the corresponding position on the opened sheet metal meeting the required size. Process: stacking pin → upper plate → drilling → lower plate → inspection repair.
Combining the above six aspects, we can judge whether the printed circuit board is “excellent”. At present, there are tens of thousands of PCB manufacturers in the market. It is suggested that users should keep their eyes open in the process of purchasing and make choices on the basis of understanding PCB.