Modelling of Energy Consumption for Milling of Circular Geometry

Abstract

Machine tools are dominant end users of electrical energy in manufacturing, and responsible for high carbon emissions. There is hardly any research work on the energy modelling for curved surface milling. The present study aims to develop energy consumption model for milling of circular geometries as a part of process planning for machining operations to reduce cost, improve energy efficiency and general productivity. The circular geometry may have concave or convex shape which leads to change in magnitude of curvature. Therefore, the magnitude and distribution of cutting forces and concerned cutting powers are quite different in both these machining situations. This necessitates the need to investigate this aspect comprehensively. A process geometry model is developed based on process geometry variables of feed per tooth along cutter contact path, entry and exit angles of tooth, engagement angle, undeformed chip thickness, etc. Next, the process geometry variables in conjunction with mechanistic cutting constants are used to develop a force model for estimating the feed force and normal force components. Lastly, a power consumption model is developed based on the instantaneous force component and velocity of milling cutter to estimate both the instantaneous and average power consumed during the milling process. Machining experiments are performed to conform the validity of the proposed model by comparing the measured power to their predicted counterpart. The developed model can be used for estimating the power consumption for milling of circular geometries reliably and efficiently without conducting the costly experiments. In addition to this, the proposed model extends the existing model by considering the effect of workpiece curvature and aims at providing a useful aid for prediction of power consumption in peripheral milling of circular surfaces. Therefore, an attempt has been made to provide a basic platform for in-depth comprehension and characterization of energy consumption. The proposed model has many applications particularly in die-mold manufacturing and aircraft industry and it can be extended to curved geometries having variable curvatures