Chip inward curl and its influence on dimensional accuracy in groove cutting with a novel restricted contact tool

Tool geometry has a significant influence on cutting force, cutting temperature, and surface quality. Restricted contact tools show good advantages in reducing cutting force, decreasing temperature, and improving surface quality. In this article, a new pattern of chip curl, “chip inward curl,” and its influence on dimensional accuracy were investigated using a novel restricted contact tool when cutting grooves. This novel restricted contact tool has symmetrical tool/chip contact length which varies along the main cutting edge and has a smaller tool land length in the middle of the rake face. In order to analyze the chip inward curl and its influence on dimensional accuracy with this novel restricted contact tool, a theoretical method to predict the chip back-flow angle using a slip-line model taking into consideration of cutting tool edge was proposed. Dimensional accuracy of the grooves achieved by this novel restricted contact tool in groove cutting tests was investigated and compared with those cut by a conventional flat-faced tool. Also, three-dimensional finite element models were developed to analyze the chip back-flow angle and chip inward curl. Results indicate that this new type of restricted contact tool has significant advantages in the control of chip curl and obtains better dimensional accuracy in groove cutting.