Método de Fabricação Rápida de PCB em Laboratório

PCB is the basic component of electronic components. fabricação de is a basic experimental skill for electronics professionals and electronic engineers. Although PCB manufacturing technology has matured sufficiently, if they just want to prove their design, it is unrealistic and unnecessary to produce circuit boards that conform to professional PCB fabrication processes because it is time-consuming and costly. Therefore, this article will provide a simple method to produce double-sided PCB, so that electronics professionals and engineers can have a better alternative.

Rapid PCB fabrication method

There are two main methods of fabricação de : chemical mode and physical mode. Today, the most popular fabricação de PCB methods in high school are thermal transfer and physical engraving. The former belongs to the field of chemistry, the latter belongs to the field of physics.

Thermal transfer printing

For thermal transfer, the first is the use of ordinary laser printers to print PCB images onto special thermal transfer paper. Then, the PCB image that has been printed on the thermal transfer paper is transferred to the copper-clad laminate (CCL) by the thermal transfer device. Finally, high-precision PCBs are produced after subsequent processes (including etching and PCB drilling). In the high school laboratory, thermal transfer printing can be used to produce high-precision PCBs and can be completed within an hour. When it comes to double-sided PCB manufacturing, a prominent problem is that misalignments that have not been successfully resolved using current manufacturing methods are not used. Therefore, the double-sided PCB manufactured by the thermal transfer method cannot achieve the best work on electronic products.

Thermal transfer printing adheres to the following PCB manufacturing process:

1. The bottom PCB image is printed on a sheet of thermal transfer paper by an ordinary laser printer.
2. The top PCB image is printed on another thermal transfer paper by a common laser printer.
3.  Two sheets of thermal transfer paper are closely attached to the well-cut double-sided CCL. Scotch tape can be used to fix the position of paper and printing plates to avoid misalignment.
4. Thermal transfer printing is performed by sticking CCL and thermal transfer paper in a thermal transfer device. Then, after cooling, the CCL printed with the PCB image is obtained.
5. Then etching and PCB drilling are performed.

The process can be summarized as the following figure:

In all stages of thermal transfer printing in PCB manufacturing, the application of step 3 can accurately lead to the alignment of two sheets of thermal transfer paper. However, when step 4 is involved, misalignment often results in heat transfer equipment. Therefore, unless several trials are conducted, double-sided PCBs are difficult to manufacture successfully.

Physical engraving

De acordo com os princípios básicos da gravação física, a gravação física está em conformidade com o princípio da fresagem. Fresagem de partes extras ou desnecessárias do CCL. O equipamento de aplicação é, na verdade, uma pequena furadeira e fresadora CNC, também conhecida como máquina de gravação de placas de circuito. No processo de fabricação de PCB, após fresar em um lado, a placa deve ser virada para fresar no outro lado da placa. O processo de inversão pode causar desalinhamento, que deve ser corrigido por meio de software e hardware para reduzir a taxa de refugo de PCBs de dupla face.

Comparação de transferência térmica e gravação física

De acordo com a comparação dos dois métodos, a transferência térmica é superior à gravação física nos seguintes aspectos:

1. As furadeiras e fresadoras CNC têm um custo mais alto e ocupam mais espaço do laboratório. No entanto, a máquina de transferência térmica tem as características de menor custo e menos espaço do que a máquina de furação e fresagem CNC.
2. Ao usar a impressão por transferência térmica, a PCB de dupla face pode ser concluída em uma hora. Embora possa haver desalinhamento de impressão por transferência térmica múltipla, uma PCB de dupla face pode ser fabricada em até 3 horas. No entanto, as máquinas de perfuração e fresagem CNC requerem mais tempo, pelo menos 4 horas. Além disso, as máquinas de perfuração e fresagem CNC podem processar apenas uma placa PCB ao mesmo tempo. A transferência térmica pode produzir várias PCBs de dupla face ao mesmo tempo.

Um método de transferência térmica aprimorado

In order to solve the problem of misalignment in traditional thermal transfer, an improved fabricação de PCB thermal transfer method will be provided, the following steps:

1. The bottom PCB image and the mirror PCB image are printed on the same thermal transfer paper. And the holes of the bottom PCB image and the top PCB image are linearly symmetrical.
2. The thermal transfer paper is folded along the line of symmetry and covered on the well-cut double-sided CCL.
3. Then put the double-sided CCL with thermal transfer paper into the thermal transfer printing device for thermal transfer. The folded part first enters the thermal transfer device, and after cooling, the CCL printed with the PCB image can be obtained. Etching and PCB drilling.

By printing the top and bottom PCB images on the same thermal transfer paper. The above process can effectively solve the misalignment problem used for PCB manufacturing in traditional thermal transfer printing. Therefore, a reliable double-sided PCB can be smoothly manufactured at one time.

The printing of PCB images on the same thermal transfer paper can be done based on any software that holds different PCB designs. All in all, this improved PCB manufacturing thermal transfer printing method is most effective for electronic professionals or engineers who can be used in the laboratory to produce double-sided PCBs.