Papers by Author: J. Ramli

Abstract: Alumina (Al₂O₃) cutting tools have been coated with carbon coating using physical vapor deposition (PVD) to improve its wear resistance. The cutting tools were subjected to surface pretreatments namely blasting and acid etching to improve the coating adhesion onto the substrates. The effects of pretreatments on the cutting tools topography prior to deposition were investigated using atomic force microscopy (AFM) while the surface morphology was investigated using scanning electron microscopy (SEM). The adhesion strength of the carbon coating was investigated using microscratch. This study shows that although the coating were deposited evenly on the surface, the cutting tool that was blasted prior to deposition has better adhesion strength when compared to acid etching and no-pretreatment.

Abstract: The potential of recycled wood flour (r-WF) addition to the thermoplastics polypropylene (PP) matrix for the composites in structural application is evaluated. The effects of different r-WF loading to the tensile and impact mechanical structural properties are analyzed. Two types of polypropylene resin which are the virgin and the recycled resin and recycled wood flour as reinforcement materials are utilized as raw materials in the composites fabrication. Various mechanical testing was conducted in accordance to ASTM standard, to study the behavior of the composites mechanical properties to the applied load. The best compounding formulation of enviro-recycled composite was found at 60wt% of PP matrix and 40wt% of the wood flour addition for both of virgin and recycle matrix. Overall experimental results showed that, the increasing of r-WF loading had significantly increased the mechanical properties of produced composite which is suitable to be applied in the application of structural engineering, through the advantage of mechanical properties performance in tensile and impact behavior. Conclusively, this finding is hoped to lead for contribution in the development of newly advanced material that is environmental friendly for the use of structural application.

Abstract: This research presents performance of nitrogen gas as a coolant in machining titanium. Compressed nitrogen gas stored in a cylindrical tank is supplied to the cutting zone via the stainless steel tube of 2x8x25mm (inside diameter x outside diameter x length) connected to the flexible hose and specially-designed valve with pressure controller. Machining experiments are carried out on conventional turning center. The cutting tool used is triangular insert of ISO-TPGN160308 with the holder (ISO-CTGPR3232K). The cutting insert grade is KC5010 (TiAlN3 coated carbide) as recommended by Kennametal for machining titanium. During machining, the tube is manually directed to be just-above the tool rake face and the nitrogen gas is supplied with high pressure so that the cutting zone receives an effective cooling as well as the chip brakes easily. The effectiveness of this new cooling strategy is demonstrated by the cutting edge condition and surface finish after machining at various speeds, and also by comparing with performance of conventional coolant. The result is found to be excellent in terms of relative amount of tool wear and surface finish. The cutting insert has surprisingly remained almost intact when using nitrogen gas coolant whereas severe tool wear occurred with conventional coolant even at low cutting speed. This cryogenic strategy also improved machined surface quality greatly.