Finger printing is one of the major scourge of PCB, which is also one of the main reasons for the bad PCB scrap and the deterioration of the reliability of the end users. Almost every link in PCB board manufacturing is run through manual operation. Only if every member in the manufacturing industry develops good habits and eliminates bare hand touchpad, will it reduce or cure the harm of finger print to PCB board. In the process of PCB processing, hand and board contact is frequent, so finger printing has become the most difficult problem in the industry.
1, finger print: finger print is hand perspiration, its main ingredients are as follows:
A, water B, inorganic salts (such as Nacl, etc.)
C, fat fat (non mineral)
D, cosmetics and skin care products E, bare hands (or dirty gloves) of all kinds of dirt
2. The harm of finger printing in the process of PCB manufacturing
A and bare material touch the plate in a very short time to make the copper chemical reaction on the surface of the plate, resulting in the oxidation of the copper surface. After a long time, there is a clear fingerprint after electroplating, and the unevenness of the coating causes serious bad appearance in the appearance of the product.
B, the bare hand contact plate before the resistance welding will lead to the resistance to welding, which leads to the poor adhesion of green oil, and will fall off when the hot air is leveled.
C, gold plate in the process of welding until after the packaging, bare hands touch the plate will lead to the plate surface is not clean and cause bad weldability, or bad state.
D, India wet film and film or screen printing line before the board with fingerprint of grease, extremely easy to cause the dry / wet film adhesion decreased, resulting in separation of plating and coating in electroplating, gold Banyi caused surface pattern, make the surface oxidation in resistance welding production, color appearance of yin and yang.
If the above phenomenon is not standardized and eliminated, it will damage the pass rate of products. The pass rate will lead to a long production and processing cycle, high rework rate and low on time delivery rate, which will damage the image of the company in the mind of customers.
3. How to eradicate the bare hand touch plate is the key link to cure the finger printing
A, requires each employee to develop a board, good habits, B carries C, gloves and finger gloves in the process can be sure to wear gloves.
B, by example, words and deeds, set up the image model, engraved in the minds of a doggerel "two hand plate edges, flat flat, palm axis coaxial rotation".