As the PCB surface welding type to lead-free conversion, circuit board welding temperature rise under ultra-high, thermal shock resistance of the surface resistance welding layer demand is higher and higher, to end surface treatment and resistance welding layer (film) ink, cover of peel strength, and the adhesion strength of the base copper demand is higher and higher, we need a has better effect of pretreatment PCB process for security. Improve our process to improve product yield and gain profit growth. High quality pre-treatment potions will undoubtedly help us a lot at a low cost.
This paper mainly introduces the problems often encountered in the production of PCB rigid circuit board and FPB flexible circuit board and the countermeasures: 1. Side corrosion and concave corrosion phenomenon occur in the etching of the line after the treatment of dry film or wet film in the line section, leading to insufficient line width or uneven line. The reason lies in the improper selection of dry and wet film materials, improper exposure parameters and poor performance of the exposure machine. The development, etch section nozzle adjustment, the related parameter adjustment is unreasonable, the liquid concentration range is improper, the transmission speed is improper, and so on series may cause the problem cause. However, we often find that after checking the above parameters and related equipment performance is not abnormal, however, when making the board, there will still be problems such as over-corrosion of circuit board, concave corrosion and so on. What is the reason?
Second, the graphics are doing PCB electroplating, PCB, FPC terminal surface treatment such as heavy gold, gold, tin, tin and other technology processing, we often find to board on the edge of the wet film or resistance weld edge, the phenomenon of the plating layer, or most of the board, or places, in either case will bring unnecessary scrap or bad bring unnecessary trouble for section after processing, and ultimately discarded, it hurts! After analyzing the reasons, we usually think that the parameters of dry and wet film and the material properties have problems. Resistance welding such as hard plate ink, soft plate cover film problems, or in the printing, pressing, curing, etc. Indeed, every one of these places can cause the problem. Then we are also confused by the examination of the above step section and no problems or problems have been solved, but there will still be the phenomenon of seepage and plating. Is there anything else that hasn’t been found out?
Iii. Circuit board will be tested with tin before shipment. Of course, customers will apply tin welding components when using. Two stages will appear likely, or will appear on the stage or immersion tin solder is bubbly, stripping substrate, is to do the tape test ink peel strength, the tensile test of soft board covering film peel strength when there will be a printing ink can be obviously stripping or covering film peel strength is insufficient or inequality problems, especially to the customers of this kind of problem precision SMT SMT customer is absolutely not acceptable. Once the light stripping phenomenon occurs in the welding process, the original parts cannot be accurately mounted, leading to the loss of a large number of components and missed work of customers, and the circuit board factory will also face huge losses such as deduction, material filling, and even loss of customers. So when we usually encounter such problems in which aspects to start? We usually go to the analysis is not welding (ink, covering film) material problem; Is there any problem with screen printing, lamination and curing stage? Is there a problem with the electroplating solution? Wait… So we usually ask engineers to make sure that they look at these sections – find the cause and make improvements. We also wonder if it’s the weather? Recently more humid, plate moisture absorption? (substrate and obstacles are easy to absorb moisture) after a hard struggle, more or less can harvest some effect, the problem is temporarily resolved on the surface. But then this kind of problem happened again, and why? The section that those may produce a problem has checked clearly improved. Is there anything else you haven’t noticed?
For the above belongs to PCB, FPC industry wide confusion, problems. We have done a lot of experiments and research, and finally found that the poor line, seepage plating, stratification, bubbling, stripping strength is not enough and so on an important reason actually lies in the pretreatment part. It includes wet and dry film pretreatment, welding resistance treatment, electroplating pretreatment and so on. Here, perhaps a lot of industry people can not help but laugh. The pretreatment is the simplest, pickling, oil removal, micro erosion. Which one of the pre-treatment potion, performance, parameters and even formula, many technical personnel in the industry are clear.