PCB design Tips: Teach you how to quickly make a circuit board

Circuit board is the carrier to realize the function of electronic circuit. As a circuit design engineer, during the product design and development stage, have you ever encountered such problems: With the improvement of electronic communication frequency, the PCB circuit accuracy requirements are higher and higher, the selection of the best makes the product reliability requirements are higher and higher, research and development projects need to be repeatedly demonstrated and modified, the research and development cycle of electronic products is shorter and shorter, circuit design engineers have to face higher challenges, how to quickly make the circuit board in the shortest time. Shortening project development time becomes one of the keys to winning.

Traditional method of rapid fabrication of circuit board

Although there are many ways to make and process circuit boards, the traditional rapid board making methods can be mainly divided into physical methods and chemical methods:

Physical methods: By using a variety of tools and power tools, the board is manually carved off the unwanted copper.

Chemical method: By coating a blank copper sheet with a protective coating, the unnecessary copper is eroded away in a corrosive solution, which is currently used by most developers. There are a variety of methods to cover the protective layer, including the most traditional manual paint method, paste custom self-adhesive method, film sensitive method and recently developed thermal transfer printing PCB board method.

Paint by hand: Paint is painted on the blank copper coated plate by hand with a brush or a hard pen. After drying, it can be put into the solution for direct corrosion.

Sticker: There are various stickers on the market are made into strips and round sheets, and different stickers are combined on the blank circuit board according to the needs, which can be corroded after sticking.

Photographic film: the PCB circuit board is printed on the film through a laser printer, and the blank copper coated plate is coated with a layer of sensitive material in advance (there are already coated copper coated plates sold in the market). After exposure, development, fixing and cleaning in the darkroom environment, it can be corroded in the solution.

Thermal transfer printing: The circuit is printed directly on the blank circuit board by a thermal transfer printer, and then put into the corrosion solution.

The two methods of making a circuit board quickly have their own advantages and disadvantages:

Physical method: This method is more laborious, and low accuracy, only relatively simple lines can be used. The main shortcomings are time-consuming, precision is not easy to control and there is no recovery, the operation requirements are very high, so few people have adopted.

Chemical method: The process is relatively complex, but the precision is controllable. It is the most widely used rapid plate making method at present, but there are still many problems.

a. Printing accuracy depends on the accuracy of the printer cartridge used. Poor performance of the printer to print out uneven lines, corrosion process is easy to cause line break, adhesion.

b. The exposure and development time of photographic plates is not easy to control, and the best exposure time of each batch of plates will be different, need to be mastered through repeated tests.

c. The corrosion process is difficult to control: it is impossible for a single etching board to be equipped with the professional control equipment used in mass production of the circuit board factory, and the temperature, concentration and pH of the corrosion solution will have a great impact on the corrosion quality. Want to do a piece of circuit board, must have a lot of experience. Otherwise, the material scrap is very serious.

d. Photographic plates require high environmental requirements and must be kept in full black and low temperature, and the exposure process must be carried out in darkroom conditions.

e. Silver salt (sensitive materials) and copper salt (corrosion products) are toxic, corrosion process operation should be very careful, stained with human or clothing is difficult to clean, and due to environmental protection reasons, after corrosion waste liquid treatment is more troublesome.

f. The etched finished plate must be worked by hand, and it is difficult to control the accuracy of hand punching.

To sum up, the traditional physical plate making method is labor-intensive, time-consuming and has low precision, while the chemical rapid plate making method has a controllable precision, but the process is complicated and unfavorable to environmental protection. Both physical and chemical methods require a lot of skill, so neither is a good way to help engineers make plates "fast." So how can we really achieve fast, high precision, convenient and low cost circuit board manufacturing?