Carbon fiber composite material has become an advanced aerospace material due to its high strength and high-temperature resistance. However, it also has its disadvantages. The interlaminar shear performance and transverse tensile performance of carbon fiber composites are relatively low. Therefore, in the drilling process of carbon fiber composite materials, defects in carbon fiber processing such as burrs, tearing, fiber pull-out, and interlayer delamination are likely to occur, which affect the wide application of carbon fiber. At present, there are carbide drill bits for carbon fiber on the market, which are specially used for processing carbon fiber composite materials.
For carbon fiber as a material, considering the production efficiency, production cost and processing quality, cemented carbide bit is the most popular one at present. Some data show that the carbide drill bits for carbon fiber is more suitable for the processing of carbon fiber composites. The reason is that the axial force is small and the drilling quality is good when drilling carbon fiber composites.
Next, we will explain the process of processing carbon fiber with carbide drill bits for carbon fiber.
1. It is generally believed that the greater the axial force, the greater the impact on the tool. Therefore, in the process of drilling, the spindle speed can be appropriately increased to reduce the feed rate per revolution within the allowable range; the production efficiency can be improved and the axial force can be obtained at the same time, so as to minimize the vibration as well as wear of the tool and prolong the service life of the tool.
2. The axial force tends to decrease as the spindle speed increases, and it increases as the feed per revolution increases. And the influence of spindle speed on axial force is less than the influence of feed. As the feed speed increases, the feed distance of the drill bit per unit time is whipped, and a larger tear is easily formed on the exit side. In addition, the processed surface quality of the hole wall is basically not affected by axial force.
3. According to the empirical formula of drilling force and exit tear length, the drilling force and exit tear length can be predicted when drilling process parameters are selected to ensure that the drilling force and outlet tear length are within the allowable range.