Mill Conditions Effect on Roughness of Injection Molds’ Forming Surfaces

Abstract

Molds work in relatively loaded conditions with a large number of working cycles; therefore, to obtain the required quality of parts, it is necessary to achieve a high quality of the forming surfaces of the molds. The analysis of existing processing technologies for molds has shown that existing technologies for ensuring the quality of forming surfaces do not take into account the influence of microgeometry on forming surfaces that arise during the machining of parts of molds. The effect on roughness resulting from the selected milling trajectory during the machining of mold surfaces is not taken into account. This leads to rapid wear of the forming parts and an increase in wear of the mold. In this paper, we study the roughness of casting surfaces, depending on the definition of milling parameters. To determine the functional dependence of the degree of roughness on the milling conditions, a full factorial experiment was performed with varying parameters and optimization factors. The functions of independent variables were presented: cutting speed—V, feed per revolution—S_o, and cutting depth—t. A set of experiments was performed using a CNC machine. Mathematical models are obtained. These mathematical models are applied when machining the molding surfaces of molds based on the choice of the optimal milling trajectory. The use of such a method allowed one to obtain an effect, speed up the technological process, and minimize abrasion of cast surfaces.