Carbon fiber composite materials are formed in one go during production and can generally only achieve relatively regular shapes, which cannot achieve all design features. This requires a large amount of secondary mechanical processing to complete the remaining design. The main secondary mechanical processing for carbon fiber composite materials includes hole processing, special shape cutting processing, blind groove processing, and surface polishing processing.

The secondary processing methods of carbon fiber composite materials mainly include traditional mechanical processing and special processing. Currently, traditional mechanical processing methods are still the main means of composite material processing. However, more and more problems are encountered in the cutting process, such as rapid tool wear and drilling delamination.

Practice has shown that due to the different properties of carbon fiber composite materials from metals, it is not possible to simply use metal cutting tools and processes in the processing of carbon fiber composite materials. Instead, many studies have mainly focused on the drilling direction of carbon fiber composite materials, which is one of the key processing techniques for carbon fiber composite materials.

The drilling processing characteristics of carbon fiber composite materials are mainly manifested in:

1. The interlayer strength of carbon fiber composite materials is low. During the drilling process, if the composite components are subjected to excessive axial drilling force, the interlayer stress will be too high, exceeding the strength of the matrix resin and causing defects such as delamination;

2. Carbon fiber composite materials belong to anisotropic materials, and the direction of fiber layup has a significant impact on hole making, especially when making holes in unidirectional plates. The stress concentration at the drilling site is high, which can easily cause defects such as splitting;

3. Carbon fiber composite materials have high hardness, and the drill bit wears out quickly during drilling;

4. Carbon fiber composite materials have poor thermal conductivity, and a large amount of frictional heat is generated between the drill bit and the composite material during drilling. However, carbon fiber composite materials have low thermal conductivity, making it difficult to eliminate heat during processing, resulting in a rapid increase in cutting zone temperature and accelerating drill bit wear.

Process measures to prevent fiber delamination at the outlet end during drilling: Under the condition of an open structure, the outlet surface of the hole should be supported and compacted with a hard high-density board, which can effectively prevent delamination and splitting at the outlet. If conditions permit, when manufacturing carbon fiber composite components, it is possible to consider adding one to two layers of glass cloth on the exit surface, which will solidify simultaneously with the component. After drilling the hole, the glass cloth can be torn off to prevent delamination at the exit surface of the hole.