Abdullah Wagiman

Development of Wood-Based Composites Material for 3D Printing Process

This paper presents the development of wood-based composites material for 3D Printing process. The aim is to characterize the waste material from wood powder (WD) as an alternative material and low cost production for rapid prototyping product. The powder blends containing wood powder (90-120µm) with commercial ZP102 material from Z Corporation was used as the composite material. The materials were mechanically blended to produce composition of WD/ZP102(vol.%) 25:70, 50:50 and 75:25 respectively. The material was successfully processed on 3D printers machine, to produce three-dimensional components and followed by post-treatment with ZMax solution to enhance the mechanical properties. The mechanical properties, dimensional accuracy and surface quality of the components were evaluated and the results were compared with the standard ZP102 material. The result shows that the mechanical properties improved with the increased of wood powder content up to 50 (vol.%). However, dimensional accuracy and surface quality were decreased as the wood content increased. Further work on powder preparation is continued for surface quality improvement.

Effect of GMAW-CMT heat input on weld bead profile geometry for freeform fabrication of aluminium parts

In developing a new method for weld based freeform fabrication, parameter affecting the geometry of single-pass need to be determined as it has great influence on dimensional accuracy and mechanical property of metallic part. In this paper, profile geometry and microstructure of single pass weld bead developed using Gas Metal Arc Welding Cold Metal Transfer (GMAW-CMT) was investigated. Observation on cross sectional weld bead indicates GMAW-CMT has capability to produce free spatter and crack defect weld bead. Profile geometry measurement shows weld bead develop at higher heat input has width size larger than the weld bead develop at lower heat input. Microstructure examination in the substrate reveals formation of columnar dendritic, cellular and planar structure while at buildup layer exhibit equiaxed dendritic structure

Effect of Heat Treatment Parameters in Plasma Arc Surface Hardening of AISI 4340 Steel

Flame hardening has been traditionally used for selective surface hardening of steel. This technique frequently resulting in imprecise harden area and part distortion when overheated. Focused heating source such as plasma arc can be an alternative to overcome this problem. In this work, plasma arc is scanned at the 4340 steel surface to improve the hardness. The variable parameters investigated were at scanning speed and operating current. Four types of surfaces were observed after they are scanned with plasma arc. They are fully-melted, partially-melted, non-melted continuous and non-melted intermittent where each type of surface has different roughness value. This work found that scanning speed and operating current has significantly influence the type of surface and roughness values. Analysis on non-melted surface gives the maximum depth of hardened layer of about 187 μm as well as hardness values of about 990 HV50. It is also observed that the depth of hardened layer and hardness value is significantly decreasing with increase in scanning speed or the decrease in operating current. Microstructure examination on hardened layer revealed that the increase of hardness is due to formation of fine grain martensitie structure.

Titanium Alloy Welding Using Middle Range Power Pulsed Wave Laser

Laser welding are well reported to be excellent in precision parts joining with high reputations in external finishing. However, the process in obtaining the best processing parameters is not an easy task. In the case of pulse wave laser, the parameter setting constrained by the laser generator specification. Each laser parameters such as pulse width tp, pulse repetition rate fp and average laser power Pavg has relation which others. Increasing one parameter will directly decreases the maximum value of other parameters. The limited applicable combination and rage of processing parameters make it difficult to obtain the optimized processing parameters. This study is conducted to investigate the influence of each lasing parameters on the welding penetration capability. The range of applicable parameters for titanium alloy sheet metal has been successfully clarified

Improving Surface Smoothness of Aluminium Alloys Multi-Bead Weld for Welding Rapid Forming Application

Understanding the interference of multi-bead parameters on surface smoothness is essential for accuracy of the formed parts made by welding rapid forming. This paper presents an investigation on surface smoothness of multi-bead aluminium alloys. Deposition path planning and overlap ratio is manipulated in order to improve surface smoothness. Observation on bead cross section indicates that deposition path planning has remarkable effect on the surface smoothness. Multi-bead that developed using continuous path planning has surface smoothness of 0.46 mm – 1.34 mm and most bead present wavy type surfaces. The surface smoothness is improved by increasing the overlap ratio. Meanwhile, skip path planning produced good surface smoothness of 0.11 mm – 0.28 mm. An improved surface smoothness featuring flat surface type is obtained with this path planning.