The Influence of Rotational Speed on the Wall Thickness and Mechanical Characteristic of Rotomouldable Plastics

Abstract

This study is interested in the main parameter of this technique that uses a cubic container with an internal dimension of 100 mm and a cylindrical container 100 mm in diameter. We implemented the work in the fifth stage: In the first stage, we designed and manufactured the multi-axial system. In the second stage, the specimens were moulded from polyester, PVC, and polyethylene at a rotational speed axis of 5–120 rpm. The results from this stage indicated that the optimal rotational speed of the steady quality in dimensions and properties of the parts are 85, 100 and 115 rpm. The third stage was concerned with the effect of the speed of rotation on the thickness of the wall. The rotational speed of the axes was changed, and the thickness of the moulded walls was measured. The laboratory measurements revealed that the maximum compression ratio with the change of speed is at the speed of 115 rpm. The fourth stage was concerned with the effect of the speed of rotation on the value of tensile strength. The rotational speed of the axes was changed, and the tensile strength of the mould was measured. The tests revealed an improvement in the tensile strength at the speed of 115 rpm compared with the other speeds. The fifth stage utilised a cylindrical mould, which was re-worked in the previous stages, to investigate the effect of the speed of rotation on the thickness of the wall and mechanical specifications. Based on the conducted experimental tests, the influence of the rotational speed, which characterized the moulding process, on selected geometrical features of the mould was studied and analysed theoretically and numerically. The results showed an increase of about 5% in the compression ratio with increased rotation speed within the range of 85 to 115 rpm. There was also an improvement of about 7% in the tensile strength with increased rotational speed from 85 to 115 rpm. These results are due to the increase in the centrifugal force on the wall of the mould during the process. Also, the study was characterized by the production of the composite of polyethylene reinforced by iron screen wire, with improvement in the mechanical properties by about 300% compared to the base material.Â