Study on the negative chamfered edge and its influence on the indexable cutting insert's lifetime and its strengthening mechanism

The longevity of hard alloy indexable cutting inserts used to cut metal parts is significantly related to their proper geometric design. Such a relationship is outstanding in an intermittent cutting scenario. One solution is to use a strengthened cutting insert with a negative chamfered edge. This method has proven to be effective in avoiding chipping and brittle fractures. However, it does have other effects, like a larger cutting force and a higher cutting heat. In the present research, a set of intermittent cutting experiments were conducted through combinations of two grades of hard alloy indexable inserts and multiple geometric parameters of cutting edges. A three-dimensional dynamometer and a high-speed camera were used to monitor and collect data on the impact and cutting force during the process. A study over the strengthening mechanism of the negative chamfer to the cutting insert was conducted using statistical analysis, which revealed the influence of those geometric parameters of cutting edges on the insert's lifetime. Further, it gave a quantified relationship between the negative chamfer parameter and the feed. This conclusion serves as both data and technical support for the design enhancement of hard alloy indexable inserts.