CNC drilling machines are indispensable equipment in modern manufacturing, and their drilling efficiency directly affects production efficiency and costs. Drilling efficiency is mainly affected by the type of drill bit used, and there are usually two main forms.

The first is to use high-speed steel drill bits, which are cheap but relatively inefficient. When used to drill plain carbon steel (Q235), the linear speed of the drill bit is about 25m/min, and the feed rate is about 0.2-0.3mm/r. Therefore, the single drilling time can be calculated by the following formula:

t (seconds) = drill diameter (mm) × workpiece thickness (mm) × 3/100.

The second is to use carbide drill bits, which are expensive but highly efficient. Carbide drill bits provided by companies such as Dijet, Sandvik, Kennametal, etc. have different linear speeds, ranging from about 80-250m/min. Compared with high-speed steel drill bits, its efficiency is increased by 3-10 times. However, due to the high price, its current application in China is not very common.

In addition to the single drilling time, some auxiliary time also needs to be considered, such as CNC movement positioning time and the initial rolling time of the drill bit. The positioning speed of CNC movement is generally between 8-12m/min. Taking all things into consideration, the drilling time is usually 1.3-1.5 times that of a single drilling time.

To sum up, the drilling efficiency of CNC drilling machines is affected by many factors, but choosing the appropriate drill bit type and reasonable process parameters can effectively improve the drilling efficiency, thereby improving production efficiency and reducing costs.