Study of thread milling cutter chip flutes inclination angle based on condition of thread milling uniformity

Abstract

The paper presents a study of thread milling cutter chip flutes inclination angle based on the condition of internal thread milling uniformity. “Uniform Thread Milling” software was developed using an analytical cut layer model and the thread milling uniformity criterion. Based on input parameters of threads, tools and feed rates during machining, a plan was drawn up and a computational experiment was conducted to determine their influence on the chip grooves tilt angle ω. The computational experiment results showed that the uniform machining process required the chip flutes inclination angle ω ≠ 0° (ω = 17°… 37°). The study obtained partial dependences and developed a general multiplicative model of the chip flutes inclination angle ω. The study of the multiplicative model showed that ω angle was mostly influenced by the number of teeth z, followed in descending order by the length of the thread-creating part of the milling cutter lr, thread diameter D, feed Sz, pitch of thread P, and thread-forming mill part diameter dr. In this case, the angle ω monotonically goes up with increasing diameter D and pitch of thread P, and monotonically decreasing when other parameters go up. The angle ω changes insignificantly with increases in mill diameter dr.