Investigation on ball end milling of P20 die steel with cutter orientation

Abstract

The generation mechanism of machininginduced residual stresses is a complex nonlinear and thermal-mechanical coupling problem. The cutting forces and cutting temperature produced in machining process must be considered simultaneously. The influence of cutter orientation and feed per tooth on the cutting speed, cutting forces, cutting temperature, and residual stresses is discussed in the present study. Effective cutting speed in accordance with the inclination angle in feed direction is analyzed. The cutting forces are gained by milling experiment, and the cutting temperature is obtained by finite element method. Moreover, the influence of the effective cutting speed on the cutting forces and cutting temperature is stated, and the relationship among the cutting forces, cutting temperature, and residual stresses is discussed. The experimental and numerical methods are both adopted in this study to give a better understanding of the milling process. After analysis of the phenomenon, several conclusions are made. The inclination angle in feed direction affects the effective cutting speed, and then the cutting forces, cutting temperature, and residual stresses are affected. Priority selection of inclination angle in feed direction is suggested from 5°to 30°in order to reduce the cutting forces. The overall trend of the workpiece temperature presents the parabolic shape, while the chip temperature increases with the increasing inclination angle in feed direction. Residual stress in feed direction almost increases with the increasing feed per tooth, which is not obvious in the general scope of the feed rate. The inclination angle of 5°and 15°is the priority in order to produce residual compressive stresses in cross feed direction.

Optimisation of machining parameters during ball end milling of hardened steel with various surface inclinations

“…In turn, the growth of rotational speed causes the reduction of cutting time and simultaneously an increase of the material removal rate. However, in this cutting mode, cutting forces are usually higher than those obtained during milling with α>0 [22,7] and hence the quality of the machined surface is reduced. Thus, the surface inclination angle during ball end milling of free form surfaces should be optimized to minimise cutting forces and maximise material removal rate.…”

“…According to Rybicki [21], an increase in surface inclination angle from 10° up to 60°, during ball end milling with constant cutting speed mode, resulted in an approximately 55% increase in cutting time. In addition, Chen et al [22] have shown that surface inclination angle has a significant influence on the cutting forces, due to variations in edge force values along the length of the cutting edge. Therefore, reliable optimisation of the ball end milling with variable surface inclinations should focus both on cutting forces and process efficiency.…”

Hybrid machining of P20 die steel masters for the development of polymer-based microfluidic devices to study the effect of surface roughness on bacterial activity

“…The properties are detailed in Table 1. 11, 29 P20 die steel is considered for the experiments because of its availability, machinability and resilience during the die casting and micro-injection moulding processes.…”

The analysis of instantaneous tool displacements during precise ball end milling

“…damping, stiffness) of machine-toolholder-tool system [8 ,9]. Moreover, in case of a ball end milling process, the variations of surface inclination angle along the toolpath cause the changes in tool's effective cutting speed and thus significantly affect the process dynamics [10]. Therefore, the identification of the crucial factors influencing the tool's instantaneous displacements during milling is important in terms of machined surface quality improvement.…”