Improving the Quality of Hole Processing with a Combined Tool

This article focused on improving the quality of hole machining using a new design of a metal-cutting tool, referred as reamer-broach. Before conducting experimental studies, fixtures were designed, a turning and screw-cutting machine was tested for geometric accuracy, and methods for evaluating the quality of the processed surface were developed. A full-factorial experiment of the 22 type was conducted to determine the influence of technological factors (rotation speed, supply) on hole accuracy, roughness, and shape deviations when machining with both a machine reamer and a reamer-broach. Additionally, an analysis of the microstructure of hole surface was performed, to prove the machinability of the material. The results indicated that an increase in feed led to an increase in the radial forces, a stabilized tool position, and a decrease in hole breakdown. An increase in rotation frequency resulted in the rise of hole breakdown as well as in an increase in surface roughness. These findings demonstrated an increase in accuracy by 1-2 quality grades compared to machine reamer and a decrease in surface roughness by 1-2 grades when processing holes using a reamer-broach.