PCB Technical - PCB cover and backing plate micro-hole drilling technology

With the rapid development of the electronics industry, printed circuit boards, which are important original parts of electronic products, have also developed rapidly. The cover plate and backing plate, as auxiliary materials for drilling the printed circuit board, play a key role in optimizing the quality of holes, reducing tool wear, increasing the life of the drill bit, and improving processing efficiency, especially the high-end PCB products for the cover backing plate. Increasingly dependent on. This article reviews the research on the micro-hole drilling technology of the cover plate for PCB micro-hole drilling.

The evaluation criteria of hole quality are hole position accuracy, burr, nail head, hole wall roughness, hole wall staining and tearing. There are many factors that affect the quality of PCB hole processing, including drilling machine performance, drill pins, circuit board materials,

and the type and thickness of the cover plate, as well as drilling process parameters and drilling environment. During the PCB drilling process, different boards will have different problems, so it is necessary to study the drilling defects of each PCB in order to find a suitable cover plate for matching. At present, some scholars have made some explorations for the drilling of different types of PCB boards.

(A) In terms of rigid printed circuit boards.

Due to the high hardness of the rigid printed circuit board material, the drilling temperature during the drilling process and the serious wear on the drill bit are the key problems of the rigid board at present.

(B) In the field of drilling holes for flexible boards.

Flexible board drilling will cause problems such as difficult discharge of drill cuttings and nail heads, as well as the impact of these problems on the quality of drilling; Wang Sihua and others use the method of orthogonal test to analyze

Analyzed the key factor affecting the drilling quality of flexible boards is the combination of auxiliary materials.

Next is the type of copper foil. The flexible circuit board has been drilled due to its poor material rigidity

The nail head problem is very easy to occur during the process. The cover and backing plate of this kind of plate can be drilled as far as possible

Choose phenolic type. Analyzed the research of micro-hole drilling and drilling quality of flexible printed circuit boards.

(3) In terms of rigid-flex board.

The steel plate is made of FR4, and the soft plate is made of PI or PET. Due to the difference between the two materials, there will be problems such as different bonding and heat compression shrinkage, so the stability of the product is more difficult to grasp.

At present, there are few research literatures on the optimal combination of cover plates used when drilling different PCB boards. Domestic research is still in its infancy, and only a few corporate personnel have conducted partial research for actual production needs. And explore.

The preparation and performance of the glued aluminum substrate for PCB drilling were analyzed. It was pointed out that the heat absorption and water solubility of the glued aluminum plate was better, which could reduce the drilling temperature;

Based on the above research, at present, the specific effects of the backing plate in the PCB drilling process are rarely involved; there are few researches on the combination of different PCB drilling cover backing plates; in addition, the drilling characteristics of different PCB boards have not yet been developed. Comparative analysis, these all need further research.