Establishment of Real-Time Adaptive Control Strategy for Milling Parameters

Abstract

The traditional method of milling which uses constant spindle speed and feedrate to prevent machine, workpiece, and machining tool failure. However, this method prevents engineers from further improving machining efficiency. It is possible to increase machining efficiency by appropriately adjusting feedrate during the machining process. Although there are plenty of researches regarding adaptive machining force control, those researches focus on the design of controller, and few of them discuss the relation between control signals and tool wear for parameters setting. This study presents a method for setting process parameters in constant load machining, including feedrate upper and lower limits, as well as reference spindle current. The reference spindle current and feedrate upper limit were selected to sustain cutting force up to tool strength. The feedrate lower limit was established to maintain tool wear conditions within a given range, preventing severe and unstable tool wear. The experimental results showed that when the feedrate was reduced to the lower limit value, the machining parameters setting method presented in this study could keep the tool wear within the set value, avoiding the risk of tool failure. The strategy for setting the machining parameters can be used to end milling, slot milling, or a combination of both milling processes. The constant load machining parameters presented in this study outperformed constant feedrate machining of the identical milling conditions in terms of tool life and material removal rate. The traditional method estimated tool life by cutting lengths, but we used the feedrate change to estimate the tool wear for change. The result showed that this method had better tool life than traditional way.

Keywords

• Adaptive machining
• constant load machining
• force control
• spindle current
• tool wear