Experimental study on the fracture morphology of chips in 50 steel internal chip removal deep hole drilling

Abstract

Relying solely on experience and trial cutting to determine the range of main process parameters for deep hole machining in order to control the cutting shape is time-consuming, laborious, and costly. This article simplifies chips into three-dimensional curved beams with rectangular cross-sections, and theoretically analyzes the stress states at different stages of their formation process, clarifying the mechanical causes of the three-dimensional shape of chips; A self-developed internal chip removal deep hole drilling device was used to drill 50 steel φ 30 mm deep hole machining experiment determined that the values of chip breakage rate and compression rate for small diameter deep hole drilling were less than 10 by calculating the chip breakage rate and compression rate of each tooth. This is a key quantitative indicator for controlling chip shape to achieve good chip breakage and removal; By using scanning electron microscopy, the microscopic morphology characteristics of the chip fracture surfaces of each tooth under different process parameter combinations were analyzed in detail, and the effects of feed rate and speed on chip morphology were explored, providing data reference for the rational selection of process parameters for small diameter inner chip removal deep hole machining.