Investigations on mechanics-based process planning of micro-end milling in machining mold cavities

In this article, a model-based micro-end milling process planning for machining micromold cavities is proposed. The goal is to facilitate proper selections of the process parameters for a given workpiece material, cavity geometry, and micro-end mill. Specifically, the axial depth of cut and the feed per tooth are critical in achieving performance objectives in terms of low cutting forces and high surface accuracy and material removal rate. An analytical model based on process mechanics is used to select feed per tooth range in micromilling to avoid size effects. Further, a time-domain simulation model is utilized to provide predictive capability in practical micromachining performance, such as cutting forces, surface form, and surface roughness. The generalized process planning strategy consists of two steps: roughing and finishing. In roughing, the objective is to control the cutting force within a predefined threshold to prevent premature tool breakage and to maximize the material removal rate. In finishing, the primary objective is to control the form error within the tolerance and to obtain satisfactory surface roughness.