With the advent of cemented carbide tools, the concept of drilling has also changed. Choosing the right carbide drill bit can greatly improve the drilling efficiency and reduce the cost of single-hole processing. Cemented carbide tool bits are divided into four basic types: solid carbide bits, cemented carbide indexable inserts, welded cemented carbide bits and replaceable cemented carbide roller bits. So, what should you pay attention to when choosing cemented carbide tools?
When choosing cemented carbide tools, the dimensional accuracy requirements of the tools must first be considered. Generally speaking, the smaller the processing aperture, the smaller the tolerance. Therefore, manufacturers usually classify tools according to the nominal diameter of the machined hole. Carbide indexable inserts are more suitable for rough machining. Although the processing cost is usually lower than other tools, the processing accuracy is relatively low, with a tolerance range of 0 to 0.3 mm.
When choosing cemented carbide tools, in addition to drilling accuracy requirements, the stability of the processing machine tool should also be considered. The stability of the machine tool is related to the safe service life and drilling accuracy of cemented carbide products. Therefore, it is necessary to carefully check the working status of the machine tool spindle, fixtures and accessories.
In addition, the stability of the cemented carbide tool itself should also be considered. For example, the hardness of the entire cemented carbide tool can achieve higher machining accuracy. However, the structural stability of cemented carbide indexable inserts is poor, and deviations are prone to occur.
Since only the inner cutting edge enters the cutting at the beginning of processing, the cemented carbide tool is in an unstable state, which is likely to cause deviation of the drill body. Therefore, when using indexable inserts of cemented carbide tools with a length greater than 4D, the feed speed should be appropriately reduced in the early stage of drilling, and the feed speed should be increased to a normal level after entering the stable cutting stage.
A common problem in the drilling process of cemented carbide tools is poor chip removal, which is inevitable no matter which tool is used. In the processing workshop, coolant is usually injected to assist chip removal, but this method is only effective when the depth of the processing hole is smaller than the hole diameter and the cutting parameters are reduced. And this requires a professional carbide manufacturer.
In order to improve productivity, cemented carbide tool manufacturers are working hard to study machining methods that can integrate various operating procedures, and develop tools that can achieve high-speed feed and high-speed machining.