Genetic equation for the prediction of tool–chip contact length in orthogonal cutting

In metal cutting, it has been acknowledged that the tool–chip contact length significantly affects many aspects of machining such as chip formation, cutting forces, cutting temperatures, tool wear and tool life. Important decrease in the tool–chip contact length, decreases the thickness of the secondary shear zone, which leads to a decrease of the cutting temperature and cutting force. As a result, it has a great effect on finish surface and tool life. Several ways have been proposed in different works to find its value, which have given discordant results for the same set of cutting conditions. In this paper, the genetic equation for the tool–chip contact length is developed with the use of the experimentally measured contact length values and genetic programming. The suggested equation has shown to correspond well with experimental data in various machining conditions with associated cutting parameters and this model predicts tool–chip contact length better than other known solutions.

► We performed machining experiments to gain data about tool–chip contact length in machining.
► Using GP methodology, a new model for tool–chip contact length in terms of cutting parameters was developed.
► The results of GP model corresponds well with associated experiments.
► Decreasing trend for the contact length will occur with increasing cutting speed which it is due to thermal softening effect.
► Noticeable rise was observed in the contact length as feed rate increased because of increasing in chip thickness.