In die and mold manufacturing, automatic feedrate-adjustment (AFA) is a key requirement for increasing productivity and accuracy of its NC machining process.
Proposed in this thesis is a model-based AFA method for maintaining smooth cutting-loads (i.e., cutting-force) during 2D-profile machining. A series of cutting experiments has been conducted to find a functional form for representing cutting-force as a function of chip-load (i.e., effective cutting-depth) and feedrate. During cutting experiments, X-axis and Y-axis forces were measured by using a tool-dynamometer and then they were combined to obtain the joint cutting-force. From the data obtained during the cutting experiments, a "chip-load/cutting-force model" representing cutting-force as a function of chip-load and feedrate is proposed.
Based on the chip-load/cutting-force model, an AFA scheme for maintaining smooth cutting-force by adjusting the feedrate (i.e., F-code) according to the changes in chip-load is presented. To check the validity of the proposed AFA scheme, another set of cutting experiments has been conducted by using feedrate-adjusted NC-data while monitoring the actual machining processes using an accelerometer. The experimental results showed that the proposed AFA-scheme was quite effective.
