1. Dimensional stability of incoming substrate materials, especially the dimensional consistency between each laminating CYCLE of the supplier; Even if the dimensional stability of different cycles of the substrate of the same specification is within the specification requirements, due to the poor consistency between them, the graphic size of the subsequent mass production of the plate is out of line due to the difference between different batches of plate materials after the first plate trial production has determined a reasonable inner layer compensation. At the same time, there is a material anomaly that the board is found to shrink in the process of the outer pattern transfer to the shape process; In the production process, it was found that the width of the panel and the length of the shipping unit had a serious contraction in relation to the outer pattern transfer ratio during the pre-shape processing data measurement process, and the ratio reached 3.6mil/10inch. The specific data are shown in the following table. After tracing, it is found that the X-RAY measurement and the graph transfer ratio of the outer layer of the abnormal batch plate are both within the control range, and no good method has been found in the process monitoring at present.

　　2, panel design: the conventional panel design is symmetrical design, in the case of normal graphic transfer ratio has no obvious impact on the graphic size of the finished PCB; However, some board parts use the design of asymmetric structure in the process of improving the utilization rate of board materials and reducing costs, which will have a very obvious impact on the graphic size consistency of finished PCB in different distribution areas. Even in the PCB processing process, we can find that the alignment of such asymmetric design plates in each link is more difficult to control and improve than that of conventional plates in the process of laser blind hole drilling and outer graphic transfer exposure/solder resistance exposure/character printing;

　　3, an inner layer graphics transfer process: here the finished PCB board size meets customer requirements plays a very critical role; For example, if the film rate compensation of an inner LAYER graphic transfer has a large deviation, it can not only directly lead TO the finished PCB graphic size failing to meet customer requirements, but also cause the subsequent laser blind hole and its bottom connection disk to align abnormally, resulting in decreased insulation performance between LAYER TO LAYER until short circuit. As well as through/blind hole alignment problem in the process of outer pattern transfer;

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