Abstract:
A plastic forming mold is important equipment for producing plastic products. Selection of a suitable material for producing the mold can improve life time of the mold and product quality. This research aims to investigate properties of three different types of mold steels and to compare the machinability among them.
Materials used in experiments were three types of mold steel with their commercial names: Daido-Nak80, Bohler-M202 and S50C by using 9 samples per each specimen. These three steels were machined using an automatic milling machine with different sets of process parameters. The sets were combinations of a feed rate of 45, 50 and 55 mm/min, a rotating rate of 510, 572 and 637 rpm, and a step cutting depth of 3, 5 and 10 mm. The cutting tool used in this experiment was an end-mill cutting tool that had a diameter of 10 mm and two cutting blades. The surfaces of the
steel machined with the given process parameters, was investigated for quality assessments including surface roughness and tool wear evaluations.
Experimental results are summarized as follows. The minimum surface roughness values of each subject were 0.593, 2.120 and 2.627 micrometers (μm) for Daido-Nak80 steel, S50C steel and Bohler-M202 steel, respectively. All of them were machined with the feed rate of 45 mm/min, the rotating rate of 637 rpm, and the cutting depth of 3 mm. The process parameter that produced the maximum degree of tool wear of the end-mill cutting blade was the feed rate of 55 mm/min, the rotating rate of 510 rpm, and the cutting depth of 10 mm when applied to the Bohler-M202 steel.