In the process of making PCB, we will encounter the problem of composition. Therefore, today I want to talk to you about the current composition methods of PCB, including the following:
1、 No space mosaic
Spacing free composition is to remove the spacing between small unit PCB boards. In this way, there is no spacing between small unit PCB boards in the board, which may lead to out of tolerance of PCB board shape. Therefore, this composition mode can be used for PCB boards with lax shape requirements. For PCB board design with strict shape requirements, it is recommended to avoid this composition mode as far as possible.
2、 Zigzag mosaic
Back form composition is a composition method adopted by the engineering preparation personnel before production in order to maximize the utilization rate of single chip and reduce the waste of each gap of single chip. As shown in Figure 1, it can effectively improve the utilization rate of materials.
3、 Reverse stitching
Reverse stitching is a way of making full use of the template space by combining the back stitching. There are two common cases of flip flopping: first, the shape of small unit PCB is “L-shaped” and flip flopped with each other, and then the shape of small unit PCB is “T-shaped” and flip flopped with each other.
4、 Program composition
Program composition is to compile a macro program in cam to import the maximum shape of small unit PCB circuit board, and directly click the composition operation to complete the composition work. Note: in the process of closing the PCB, it needs to be used as the maximum outline of the circuit board. Otherwise, it needs to be used as the outline of the circuit board. In the process of closing the circuit board, it needs to be automatically corrected as the outline of the circuit board. This way reduces the mistakes caused by human factors and improves the efficiency of making up. Make up the program with the “T-shaped” board in Figure 3, and the results are shown in Figure 4. Because there are not many special-shaped boards, application assembly is carried out in most cases in PCB circuit board factories.
5、 Mixed composition
Hybrid composition is to select the best of the above composition methods and absorb the advantages of various composition methods, which can effectively improve the utilization rate of layout and single chip. Take the “T-shaped” reverse stitching composition in Figure 3 as an example. If this composition method is slightly changed, the utilization rate of a single chip will be improved.
Firstly, the small unit PCB circuit board is combined to form an “L-shaped” large unit, and then the assembly is carried out according to the back shape assembly. Finally, the small unit is supplemented to complete the assembly.
For different PCB manufacturers, the way to choose the composition is also different. For the case of small batch and multiple types, the program composition can be considered, with short composition time and low error rate; For mass production, we need to consider the utilization rate of materials and bottleneck equipment, as well as other ways of composition.