Now showing 1 - 10 of 10
  • Publication
    Evaluation of shrinkage and weld line strength of thick flat part in injection moulding process
    ( 2021-10-01)
    Nasir S.M.
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    Sharif S.
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    Abdellah A.E.h.
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    This paper evaluates the shrinkage and strength of weld line using Design of Experiment and Response Surface Methodology in multi-objective optimisation utilising the injection moulding parameters. A simulation process was conducted to determine the recommended setting of injection moulding parameters and the range of the variable parameters. An experimental work was conducted according to the experimental design, where regression models were established to predict the shrinkage and weld line strength. A new set of process parameters setting was found to achieve the optimum shrinkage and weld line strength of the moulded part. The results of shrinkage and weld line strength using an optimal parameter setting after optimisation process were compared with the results obtained using the recommended setting from Autodesk Moldflow Insight software. It was found that the shrinkages in the normal to and parallel to the melt flow directions were reduced by 5.969% and 4.375%, respectively, through the predicted model generated using RSM. On the other hand, the weld line strength improved by 3.758% as compared to the weld line strength obtained from the recommended setting. The shrinkages in both parallel to and normal to the melt flow directions using multi-objective optimisation were reduced by 5.891% and 4.160%, respectively, while the weld line strength was improved by 3.756%, using the combination of the following parameters; 69.93 Â°C of coolant inlet temperature, 270 Â°C of melt temperature, 70 MPa of packing pressure and 8 s of cooling time. The predicted errors ranged between 0.2 and 14.5% during the validation experiments. The packing pressure was found to be the most significant parameter affecting the shrinkage in both parallel to and normal to melt flow directions. The coolant inlet temperature on the other hand was the most significant parameter affecting the weld line strength.
  • Publication
    Room Temperature Synthesis and Characterization of HKUST-1, Metal–Organic Frameworks (MOFs)
    ( 2023-01-01)
    Ahmad S.
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    Mahdi E.M.
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    Md. Akil H.
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    Nosbi N.
    In the present work, HKUST-1 has been synthesized at room temperature with 1:0, 1:1, and 0:1 ratio of ethanol and water. A wide range of reaction conditions were explored in order to understand the effects of solvent and temperature. It was discovered that various precursors yielded products with various BET specific surface areas. The effect of water may therefore be explained by the decrease in reaction rate with an increasing concentration of reactants. The XRD data and SEM analysis showed that both MOFs were very crystalline in the product.
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  • Publication
    Influence of filler surface modification on static and dynamic mechanical responses of rice husk reinforced linear low-density polyethylene composites
    Filler surface modification has become an essential approach to improve the compatibility problem between natural fillers and polymer matrices. However, there is limited work that concerns on this particular effect under dynamic loading conditions. Therefore, in this study, both untreated and treated low linear density polyethylene/rice husk composites were tested under static (0.001 s-1, 0.01 s-1and 0.1 s-1) and dynamic loading rates (650 s-1, 900 s-1and 1100 s-1) using universal testing machine and split Hopkinson pressure bar equipment, respectively. Rice husk filler was modified using silane coupling agents at four different concentrations (1, 3, 5 and 7% weight percentage of silane) at room temperature. This surface modification was experimentally proven by Fourier transform infrared and Field emission scanning electron microscopy. Results show that strength properties, stiffness properties and yield behaviour of treated composites were higher than untreated composites. Among the treated composites, the 5% silane weight percentage composite shows the optimum mechanical properties. Besides, the rate of sensitivity of both untreated and treated composites also shows great dependency on strain rate sensitivity with increasing strain rate. On the other hand, the thermal activation volume shows contrary trend. For fracture surface analysis, the results show that the treated LLDPE/RH composites experienced less permanent deformation as compared to untreated LLDPE/RH composites. Besides, at dynamic loading, the fracture surface analysis of the treated composites showed good attachment between RH and LLDPE.
      1
  • Publication
    A review on the potential of polylactic acid based thermoplastic elastomer as filament material for fused deposition modelling
    ( 2022-09-01) ;
    Krishna Kumar N.
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    Watson Rennie A.E.
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    Yousefi Kanani A.
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    Currently, a range of sectors are implementing three-dimensional (3D) printing, which is a part of additive manufacturing (AM) technology via the fused deposition modelling (FDM) approach. As of now, various filament materials are available in the market and have their limitations. Thermoplastic elastomer (TPE) blend as a filament material in 3D printing should be implemented to overcome the weakness of available filaments. TPE blend stands out due to its flexibility, thermoplastic-like processability, and renewability. Based on the findings, TPE blend filament can be made with polylactic acid (PLA) thermoplastic and elastomers such as natural rubber (NR) and epoxidized natural rubber (ENR). The TPE printed components will be flexible; tough with excellent thermal and mechanical properties. In this paper, the characteristics of TPE are being reviewed to show the potential of TPE material as filament.
      2
  • Publication
    Warpage optimisation using recycled polycar-bonates (PC) on front panel housing
    ( 2021-03-02)
    Tamizi N.A.M.A.
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    Abdellah A.E.H.
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    Nabiałek M.
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    Wysłocki J.J.
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    Jeż B.
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    Palutkiewicz P.
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    Many studies have been done using recycled waste materials to minimise environmental problems. It is a great opportunity to explore mechanical recycling and the use of recycled and virgin blend as a material to produce new products with minimum defects. In this study, appropriate processing parameters were considered to mould the front panel housing part using R0% (virgin), R30% (30% virgin: 70% recycled), R40% (40% virgin: 60% recycled) and R50% (50% virgin: 50% recycled) of Polycarbonate (PC). The manufacturing ability and quality during preliminary stage can be predicted through simulation analysis using Autodesk Moldflow Insight 2012 software. The recommended processing parameters and values of warpage in x and y directions can also be obtained using this software. No value of warpage was obtained from simulation studies for x direction on the front panel housing. Therefore, this study only focused on reducing the warpage in the y direction. Response Surface Methodology (RSM) and Genetic Algorithm (GA) optimisation methods were used to find the optimal processing parameters. As the results, the optimal ratio of recycled PC material was found to be R30%, followed by R40% and R50% materials using RSM and GA methods as compared to the average value of warpage on the moulded part using R0%. The most influential processing parameter that contributed to warpage defect was packing pressure for all materials used in this study.
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  • Publication
    Optimization of injection moulding process via Design of Experiment (DOE) method based on Rice Husk (RH) reinforced Low Density Polyethylene (LDPE) composite properties
    Optimal parameters setting of injection moulding (IM) machine critically effects productivity, quality, and cost production of end products in manufacturing industries. Previously, trial and error method were the most common method for the production engineers to meet the optimal process injection moulding parameter setting. Inappropriate injection moulding machine parameter settings can lead to poor production and quality of a product. Therefore, this study was purposefully carried out to overcome those uncertainty. This paper presents a statistical technique on the optimization of injection moulding process parameters through central composite design (CCD). In this study, an understanding of the injection moulding process and consequently its optimization is carried out by CCD based on three parameters (melt temperature, packing pressure, and cooling time) which influence the shrinkage and tensile strength of rice husk (RH) reinforced low density polyethylene (LDPE) composites. Statistical results and analysis are used to provide better interpretation of the experiment. The models are form from analysis of variance (ANOVA) method and the model passed the tests for normality and independence assumptions.
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  • Publication
    Optimisation of shrinkage and strength on thick plate part using recycled ldpe materials
    ( 2021-04-01)
    Roslan N.
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    Abdellah A.E.H.
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    Błoch K.
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    Pietrusiewicz P.
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    Nabiałek M.
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    Szmidla J.
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    Kwiatkowski D.
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    Vasco J.O.C.
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    Achieving good quality of products from plastic injection moulding processes is very challenging, since the process comprises many affecting parameters. Common defects such as warpage are hard to avoid, and the defective parts will eventually go to waste, leading to unnecessary costs to the manufacturer. The use of recycled material from postindustrial waste has been studied by a few researchers. However, the application of an optimisation method by which to optimise processing parameters to mould parts using recycled materials remains lacking. In this study, Response Surface Methodology (RSM) and Particle Swarm Optimisation (PSO) methods were conducted on thick plate parts moulded using virgin and recycled low-density polyethylene (LDPE) materials (100:0, 70:30, 60:40 and 50:50; virgin to recycle material ratios) to find the optimal input parameters for each of the material ratios. Shrinkage in the x and y directions increased in correlation with the recycled ratio, compared to virgin material. Meanwhile, the tensile strength of the thick plate part continued to decrease when the recycled ratio increased. R30 (70:30) had the optimum shrinkage in the x direction with respect to R0 (100:0) material where the shrinkage increased by 24.49% (RSM) and 33.20% (PSO). On the other hand, the shrinkage in the y direction for R30 material increased by 4.48% (RSM) and decreased by 2.67% (PSO), while the tensile strength of R30 (70:30) material decreased by 0.51% (RSM) and 2.68% (PSO) as compared to R0 (100:0) material. Validation tests indicated that the optimal setting of processing parameter suggested by PSO and RSM for R0 (100:0), R30 (70:30), R40 (60:40) and R50 (50:50) was less than 10%.
      2
  • Publication
    Recent developments in fire retardant glass fibre reinforced epoxy composite and geopolymer as a potential fire-retardant material: A review
    Glass fibre reinforced epoxy composites have been used in building area (cold store construction), aeroplanes, land and water vehicles, etc., due to their high-specific rigidity and strength, high damping, great resistance to corrosion, and inferior thermal expansion. Unfortunately, epoxy is flammable whilst releasing a substantial amount of smoke and gases, and therefore presenting a possible risk to lives as well as property. The reduction of their fire risks is normally fulfilled by enhancing the fire performance of composite components including the incorporation of fire retardant (FR) into the polymer matrix and by providing protective FR coatings around the composite. To date, two types of FR have been incorporated into the composite system including additive and reactive FR to improve the fire performance of the composite. This review focuses on the research works over the last ten years in improving fire retardancy of glass fibre reinforced epoxy composite through the incorporation of both types of FR. This work also summarises research works regarding geopolymer which is applied on enhancing fire retardancy of epoxy-based material. Finally, this work presents some future research opportunities as regards to the potential of geopolymer to be utilised as one of FRs to improve fire retardancy of glass fibre reinforced epoxy composite.
      2
  • Publication
    Producing Metal Powder from Machining Chips Using Ball Milling Process: A Review
    ( 2023-07-01) ; ; ;
    Yin A.T.M.
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    NemeÈ™ O.
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    Sandu A.V.
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    Vizureanu P.
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    Abdellah A.E.h.
    In the pursuit of achieving zero emissions, exploring the concept of recycling metal waste from industries and workshops (i.e., waste-free) is essential. This is because metal recycling not only helps conserve natural resources but also requires less energy as compared to the production of new products from virgin raw materials. The use of metal scrap in rapid tooling (RT) for injection molding is an interesting and viable approach. Recycling methods enable the recovery of valuable metal powders from various sources, such as electronic, industrial, and automobile scrap. Mechanical alloying is a potential opportunity for sustainable powder production as it has the capability to convert various starting materials with different initial sizes into powder particles through the ball milling process. Nevertheless, parameter factors, such as the type of ball milling, ball-to-powder ratio (BPR), rotation speed, grinding period, size and shape of the milling media, and process control agent (PCA), can influence the quality and characteristics of the metal powders produced. Despite potential drawbacks and environmental impacts, this process can still be a valuable method for recycling metals into powders. Further research is required to optimize the process. Furthermore, ball milling has been widely used in various industries, including recycling and metal mold production, to improve product properties in an environmentally friendly way. This review found that ball milling is the best tool for reducing the particle size of recycled metal chips and creating new metal powders to enhance mechanical properties and novelty for mold additive manufacturing (MAM) applications. Therefore, it is necessary to conduct further research on various parameters associated with ball milling to optimize the process of converting recycled copper chips into powder. This research will assist in attaining the highest level of efficiency and effectiveness in particle size reduction and powder quality. Lastly, this review also presents potential avenues for future research by exploring the application of RT in the ball milling technique.
      2
  • Publication
    Hydroxyapatite/Dolomite alkaline activated material reaction in the formation of low temperature sintered ceramic as adsorbent materials
    Hazardous pollutants, especially heavy metals in wastewater, have become a major concern due to the high potential of causing serious problems to humans and aquatic ecosystems, such as adverse health effects, environmental damage, and air pollution. The adsorption process is widely used to remove heavy metals because it is inexpensive, simple, and environmentally friendly. However, recent studies have shown that some adsorbents such as activated carbon, ion exchange resins, and carbon nanotubes are becoming more expensive due to their complex production. Considering these problems, alkali-activated materials (AAMs) can be considered as a new potential adsorbent material due to their excellent physical, chemical, and mechanical properties, which make them suitable for use in the field of civil engineering. Dolomite is one of the AAMs that is capable of adsorbing hazardous pollutants such as heavy metals in wastewater due to its unique structure. This material is also classified as a cost-effective adsorbent because it is abundant and can be found all over the world. Nevertheless, few studies have focused on the adsorption method using dolomite as a precursor material to remove heavy metals in wastewater, and currently only limited studies focus on the relationship between dolomite and hydroxyapatite (HAP). In addition, some studies have shown that the properties of geopolymers can be improved (up to 40%) when a moderate amount of calcium-containing material is added to the geopolymer. Although they have been used as a stand-alone material with excellent properties, combining them with another material could be another way to improve their properties. Therefore, this review provides an in-depth analysis on the properties of dolomite as a new potential precursor material in combination with HAP for contaminant removal. This would help to find the best parameters for the geopolymerization process between dolomite and HAP to meet the adsorption method requirements. This paper also investigated the ability of HAP as a carrier with the combination of bacterial strains via an immobilization process to improve the properties of dolomite as a geopolymer adsorbent. A microbial community can also act as an adsorbent for the removal of heavy metals and inorganic/organic contaminants from wastewater. This review can serve as a basis for understanding the ability of dolomite/HAP as a new alkali-activated material in geopolymer adsorbents in combination with immobilizing bacteria to remove heavy metals in wastewaters.
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