Effect of oil palm fibre addition on the mechanical properties of shell mould investment casting

Abstract

This research is aimed to investigate the effect of addition of organic fibre on the mechanical properties of the investment casting ceramic mould based on different length of fibres in the investment. Modulus of rupture (MOR) and permeability of the ceramic mould are evaluated. The MOR test contains three systems: green (undewaxed), green (dewaxed) and fired. The permeability test contains two systems: green (dewaxed) and fired. For the variation of fibre length, 3mm, 5mm, 7mm, 9mm are established. In each system, the MOR and permeability are compared between the fibre addition specimens and the non fibre addition specimen. Oil palm empty fruit bunch fibre is used as the additive in the investments. Colloidal silica and zircon sand are used to produce the ceramic mould. Firing temperature used is 700ºC. MOR three point bending testing machine is used to evaluate the strength of the mould. Permeability tester is used to evaluate the permeability of the mould upon the addition of fibres. The results obtained indicated that for the MOR test, the green (dewaxed) system has the highest MOR values than the fired and green (undewaxed) systems. The fired system is shown to have lowest MOR values among the three systems. For the permeability test, as expected. the fired system fibre addition specimens have higher permeability value than the green system.