Shahrul Azam Abdullah

Effect of Die Gap and Punch Travel on Springback in Air V-Bending Process Using Taguchi Method

Springback is a serious problem for the manufacturing industry due to error in the appearance of the final product especially in bending process. Therefore, its important to investigate the factors that affect the springback behavior . This paper focused on the effect of two parameters, namely die gap and punch travel on springback behavior in air V-die bending process for stainless steel sheet metal. Different values of die gap and punch travel were experimentally used and the final bent angle was measured. Design of Experiments (DoE) was based on Taguchi Method (TM) and the optimum parameters was obtained using signal-to-noise (S/N) ratio. Further analyzed, Analysis of Variance (ANOVA) techniques was carried out to investigate which of the factors are significance on springback effect. The result show that punch travel is the most significance factor than die gap factor based on p-value for punch travel and die gap were 0.003 and 0.045, respectively. From this two factors, punch travel is most considered to reduce springback phenomenon compared to die gap and the effect could be improved through modification of this parameter.

Dimensional and Thermal Stabilities of Nanomodified-Epoxy Systems

The effect of nanosilica, multiwalled carbon nanotubes (MWCNT) and montmorillonite (MMT) nanoclay on thermal properties of Epikote 828 epoxy polymer was studied. Thermo-mechanical analysis was conducted on three types of nanocomposites which contain 5-25 wt% nanosilica, 0.5-1 wt% MWCNT and 1-5 wt% MMT nanoclay. The effect of nanofillers on the coefficient of thermal expansion (CTE), thermal strain and glass transition temperature (Tg) of the modified and unmodified resins was investigated. It was found that the addition of nanofiller improved the dimensional stability of the polymer. All nanomodified-polymer systems have lower CTE compared to that of the unmodified resin.

Thermal and Electrical Conductivities of Carbon Fibers and Carbon Nanotubes Incorporated Polyurethanes Composites

Single filler polyurethane composites with carbon fibers (CFs) and multi-walled carbon nanotubes (MWNTs) were prepared by melt mixing methods and its thermal as well as electrical resistivity characteristics were investigated. The influences of fillers and mixing methods on thermal and electrical conductivity of CF/- and MWNT/polyurethane composites were investigated and the result shows that the addition of carbon fillers improved the thermal conductivity of the polyurethane composites. Higher filler concentration results in better thermal conductivity because better formation of thermally conductive networks along polymer matrix to ensure the thermal was conducted through the matrix and the network along the polymer composites. The presence of carbon additives improves the electrical resistivity of the materials as well. The present study revealed the potential of carbon as agent for better thermal and electrical conductivities and their properties depend strongly on the dispersion and distribution of the fillers in the polymer matrix.

Simulation and Experimental Investigation of Springback in Air V-Bending Process Using Finite Element Method (FEM)

This paper presents an investigation on cold bending process using simulation and experimental study. The experimental and simulation was performed on stainless steel 304 sheet metal in air V-bending. The factors involved in the process are punch radius, die radius, die gap, punch travel and punch velocity. The aim of this paper is to investigate the factors that affect the springback behavior of stainless steel in air V-bending using Finite Element Method (FEM) software Simufact-FormingTM version 11.0 and material database MatILDa. The simulation parameters followed the actual setting under consideration of the machine characteristic and friction. The simufact.formingTM simulation was further verified using hydraulic press machine with determine the desired speed of the forming punch. As the final result, comparison effect of springback between simulation and experiment is presented. It can be concluded that Simufact.formingTM software can gave fast solution analysis time in prediction of springback affact with good agreement between simulation and experimental.

An Overview of the Impacts of Material Parameters on Springback

Springback is a serious problem in the manufacturing industry due to errors that effects the appearance of the final product especially in the sheet forming process. This paper presents the review on past literature regarding factors that affects the amount of springback that occurs after the forming operation. This paper focus on 5 major elements that affects the value of springback including yield stress (σy), Young’s modulus (E), strain hardening exponent (n), Poisson’s Ratio (v) and thickness of the sheet (t). This 5 elements show that, increases in the value of (σy), (n), will increase the value of springback. The springback decreases with increasing of (t) and (E). While (v) has a small significant effect on springback. The effects of these factors can be used as a guide when considering further research on springback.

New mouth spacer design for dental application

Mouth spacer is designed to keep the mouth open wide enough for the dentist during dental procedures. Designing and developing a mouth spacer that able to open mouth wide enough and limit the tongue movement is the main objectives for this paper. The new mouth spacer design is expected to reduce gums and jaws pain. This paper incorporates problem identification, idea generation and conceptualization stage in order to generate two design concepts for new mouth spacer designed. The mouth spacer conceptual design with dual function that complied with these project objectives was selected. This design was modeled by using of CATIA software and the suggested material is polyvinylacetate polyethylene (EVA) copolymer and application of silicone sponge gel on the side for patient comfort and satisfaction. The mock up design was prepared using RP machine to visualize the conceptual design. Above all, this paper gives detailed description function of the mouth spacer that may improve the dental surgery application towards a better procedure.