With the development of electronic communication technology continues to improve, more and more traditional manufacturing method for circuit board can not meet the high-speed development of the era, you really want to quickly produce high precision, good performance, and can save the cost of the PCB circuit board, this is undoubtedly the biggest challenge for the circuit design engineering division.
First: the rapid production of circuit board method
There are many ways of making and processing circuit board, but the main methods are two kinds of physical and chemical methods:
Physical method: by using a variety of tools and power tools, hand on the circuit board does not need to cut copper.
Chemical methods: by covering the protective layer on a blank copper clad laminate, the removal of unwanted copper in a corrosive solution is the most popular method currently used by developers. There are a variety of methods to cover the protective layer, mainly the most traditional manual painting method, paste custom adhesive method, film sensitization method and the development of the heat transfer printing PCB plate method in recent years.
Hand painted paint: paint with a brush or a hard pen in the blank on the copper plate to describe the shape of the line, after drying can be put into the solution of the direct corrosion.
Adhesive: there are all kinds of stickers are made of strip and the wafer in the blank on the circuit board according to the needs of different combinations of adhesive can be cemented after corrosion.
Film: the PCB circuit board by laser printer to print on the film, the blank CCL pre coated with a layer of photosensitive material (CCL is coated with the market sale), exposure in the darkroom environment, developing and fixing, immediately after cleaning in solution corrosion.
Heat transfer: through the thermal transfer printer to print the line directly on the blank circuit board, and then into the corrosion of corrosive liquid.
Second: the advantages and disadvantages of two kinds of fast circuit board method
Physical method: this method is laborious, and the accuracy is low, only relatively simple lines can be used. The main drawback of time-consuming, the precision is not easy to control and there are no recoverability, high operational requirements, at present has rarely been used.
Chemical methods: the process is relatively complex, but the accuracy of control, is currently the most widely used rapid plate making method, but there are still many problems.
1) printing accuracy depends on the accuracy of the printer cartridges used. Poor performance of the printer print out the line is not uniform, the process of corrosion prone to disconnection, adhesion.
2) the exposure and development time of photosensitive plate is not easy to control, and the optimal exposure time of each batch of plate will be different, which needs to be controlled through repeated experiments.
3) the difficulty of controlling the corrosion process: high corrosion can not be monolithic plate equipped with circuit board factory mass production of professional equipment and corrosion control, solution temperature, concentration and pH will have a greater impact on the quality of corrosion. Want to do a circuit board, there must be a number of experience accumulation. Otherwise, scrap material is very serious.
4) plate to higher environmental requirements, must be kept in the dark under the condition of low temperature, the exposure process must be carried out under the condition of darkness.
(5) silver halide photosensitive material) and copper salt (corrosion) are toxic, be very careful in the corrosion process, with human body or clothing is difficult to clean, and because of environmental reasons, corrosion after wastewater treatment more trouble.
6) the finished product must be operated manually, and the manual drilling is difficult to control.
At present, digital electronic products, automobile, medical etc. these products for circuit board production process and speed requirements are more stringent, so, as a design engineer must have a solid foundation to consolidate and circuit production and skilled operating skills, and slowly accumulated and summarized.