Papers by Keyword: Injection Moulding

Abstract: Plastic injection moulding is widely used for manufacturing due to variety of plastic product. In this study, plastic part defects such as air bubble and gas mark defect are commonly occurs in thermoplastic part, specifically acrylonitrile butadiene styrene (ABS). In order to optimize the process parameters of injection moulding, design of experiment (DOE) with Response Surface Methodology (RSM) model was used. Process parameters such as melt temperature, mould temperature and injection pressure were selected for the DOE development. The experiments were conducted with melt temperature range from 200 °C to 240 °C, mould temperature from 60 °C to 80 °C and injection pressure from 90 to 99%. The result indicates that, all the selected parameters were significantly influence the rejection rate of the automotive ABS part. The optimum melt temperature, mould temperature and injection pressure were 220 °C, 70 °C and 98% respectively, in obtaining minimum rejection rate.

Abstract: Recent developments in the field of tissue engineering recommend the 3D printing to obtain the complex shape of the final alloplastic grafts (for soft or hard tissues). The medium pressure injection moulding (MEDPIM) technology could be a cost-effective alternative to 3D printing. This paper presents the first studies for the MEDPIM applicability in the case of some alloplastic bone grafts manufacturing. Two biocomposite feedstocks have been researched in order to obtain the injected parts (herein after named green parts). The Ti6Al4V respectively TiH₂, both as powder particles, were mixed with hydroxyapatite (HAP) powders in the W 50 EHT measuring mixer. Both powder mixtures contain NaCl as foaming agent as well as some wax-based binders. The MEDPIM process is developed in the laboratory-scale device, designed and manufactured in the frame of the research project BONY. This device replicates, at lab-scale, the MEDPIM process developed by the Goceram MEDPIMOULD equipment, able to work at mass-production scale. The injection moulding tests were performed at the temperature range of 50…110°C, respectively at 30-45 MPa as injection pressure. The green parts quality was evaluated by means of the physical characteristics (dimensional and density measurements) as well as macroscopic evaluation using the stereomicroscope NIKON SMZ 745T. The influence of the biocomposite feedstock type as well as the injection temperature on the green pats quality is studied in this research.

Abstract: Acrylonitrile Butadiene Styrene (ABS) polymer and Polytetrafluroethylene (PTFE) polymer has different properties individually. In this work ABS is used as matrix and PTFE is used as particle reinforcement. ABS is a copolymer containing butadiene, styrene and acrylonitrile. This work is to focus about the thermal property of ABS copolymer by adding PTFE as particle in polymer composites. From the analysis PTFE fit into a perfect particle reinforcement material for a broad assortment of utilizations. The samples is prepared with 100% ABS and 10% PTFE by weight, 20% PTFE is added to ABS and fabricated with Injection molding process. The addition of PTFE to ABS has improved on thermal properties. Experiment results shows that PTFE filler added composites exhibited high thermal conductivities and good coefficient of linear thermal expansion when compared with pure ABS copolymer.

Abstract: In this Paper, the application of Taguchi Method (TM) on the process parameters of Injection Moulding of Polybutylene Terephthalate (PBT) is presented. The influence of process parameters, such as Injection Pressure, Suckback Pressure, Injection Time, Cooling Time, Zone 1 Temperature & Zone 2 Temperature (Barrel Temperatures) on Dark Spots and Short Shots (defects) were investigated using the Orthogonal Array L₁₆ of Taguchi Method for 6 factors at 2 levels each with the response being percent defectives. It was found that Injection Pressure, Injection Time & Zone 1 Temperature had a major effect on the response. After the application of Taguchi Method, the rejection rate dropped down to 5.84% from 11.33%, which is a 48.45% reduction.

Abstract: The purpose of this research is to reduce the defect rate from the manufacturing process of in-mould decoration (IMD), the process combining PET film with decorative patterns are moulded together with ABS resins, which has been developed to reduce the secondary process of decorative screen printing. Recently, the case study company has produced components with a high defect rate, which increased sharply to 22.3% in June 2018. The major causes of the defect resulting from PET film peeled off. In order to reduce the defect rate, the five steps of the DMAIC Six Sigma methodology are implemented. The detail of the IMD manufacturing process was studied to identify appropriate measurement methods and factors affecting PET film peeled off by using the cause and effect diagram and its scoring matrix. Then the prioritized factors were analyzed and selected from FMEA to conduct the design of experiment (DOE) to find significant factors and optimal parameter settings for improvement and control process to prevent reoccurrence. After improvement of PET film peeled off by setting appropriate parameter as well as implementing control plans and Standard Operation Procedure (SOP) to eliminate other defects from in-mould decoration process, the result shows that the defect rate of in-mould decoration process decreased from 22.3% to 0.7% in July 2018.

Abstract: The existing metallic solutions used for vertical traffic signs are associated with higher costs and environmental issues due to their manufacturing and degradation, when compared with polymeric solutions. Thus, the development of vertical signs considering the injection from polymeric materials in order to overcome problems related with sustainability, maintenance costs, and to achieve higher resistance to corrosion assumes nowadays an important role. The use of eco-friendly and innovative products considering the industrial waste combined with synthetic polymers performing the appropriate mechanical properties, can also be studied to find out new solutions that allow to solve the aforementioned problems. Additionally, these innovative vertical signs can contribute to avoid vandalism events related with theft and graffiti activities. This work presents the prior materials investigation and the structural design of vertical signs that are intended to be produced through polymer injection. Three main steps were considered: i) materials research, ii) materials characterisation through the analysis of polycarbonate resin isolated and in different sets of mixtures with different concentrations through tensile testing and static water contact angle measurements to find the optimal material composition; and iii) structural numerical simulation considering polycarbonate resin and using the current standard EN 12899-1 [1] to compute wind resistance, temporary and permanent deflections. Both experimental and numerical results led to an optimized proposal of the vertical signposting structural design.

Abstract: A Continuum (filled polymer) is inhomogeneous and anisotropic. The Continuum is used in an injection moulding simulation at first (generally unnewton type of fluid). Then the continuum is solid (after cooling) and it is possible to carry out ordinary structural analysis with it both static and dynamic. The solid continuum has different mechanical properties for each of discrete element. The consequent values of mechanical characteristics (after simulation of load) will generally have different values when influence of injection moulding is taken into account for analyses.

Abstract: The raw material to be compacted by moulding is represented by aluminium alloy (ALUMIX 321) powder particles as metallic matrix and carbamide as foaming agent. The raw material to be injected is represented by the mixture (feedstock) between the wax-based binder system (40-60% mass) and the aluminium alloy (ALUMIX 321) powder particles (balance). The binder system is made of paraffin wax and stearic acid. The foaming effect is generated by addition of carbamide as foaming agent. Both categories of raw samples were washed in the ultrasonic machine and the aim of research was to study the physical properties and the macroscopic analysis of this materials.

Abstract: The purpose of this research is to optimise the processing condition of injection moulding towards samples made from polypropylene-nanoclay-bamboo fibre with compatibilizer. The defects that have been controlled upon the optimisation were shrinkage and warpage. The selection of injection moulding processing condition was packing pressure, melt temperature, screw speed and filling time. The research started by drying the bamboo fibres at 120°C. Then, the 1 wt. % fibres were mixed with 79 wt. % of polypropylene, 15 wt. % of compatibilizer and 5 wt. % of nanoclay. The mixing process was performed by using Brabender Plastograph machine. After that, pallets were produced by using Plastic Granulator machine for injection moulding process. The optimisation process was accomplished by adopting the Taguchi method. According to the results, the value of warpage defect between compounding for 1 wt. % fibre and without fibre content was not significant. However the optimum setting of 170°C melt temperature, 35% packing pressure, 30% screw speed and 2 seconds filling time can significantly reduce shrinkage. In conclusion, the optimum processing condition of polypropylene-nanoclay, fibre bamboo had been achieved, and the existence of fibre obviously giving a promising manufacturing opportunity to improve the quality of the injected moulding products.

Abstract: The characterization of CIM feedstock consisting 58, 59, 60vol% of YSZ powder with binder system comprising a palm stearin (PS) and low density polyethylene (LDPE) were studied. The effects of powder loading and temperature (°C) on the rheological behavior of the YSZ were investigated by using Rosand RH2000 Capillary Rheometer. The results showed all the feedstock achieved desirable injection moulding characteristics such as pseudoplastic behavior, flow behavior index (n) less than 1 and low activation energy (E). The rectangular parts were successfully injected moulded at optimum temperature of 170°C with the highest green strength was 12.7 N, obtained from 60 vol% powder loading which correspond to greater density and low porosity of the samples.