Injection moulding process is well known in plastic moulding industries. The development of this process had caused an increase in the plastic materials used to mould plastic product. Two types of waste were generated during processing, which are postindustrial waste and postcunsumer waste. The use of postindindustrial waste as the recycled material, mixed with virgin material typically has distinct advantages where it is clean and the composition of polymer is known. The quality of product produced by mixing virgin and recycled materials will be different from the product produced using virgin material only. Warpage is one of the defects that normally occur on moulded parts as affect the dimensions of parts and assembly process. The use of appropriate blends ration between virgin and recycled materials was reported as the effective way to improve the quality of moulded parts rather than using 100% recycled material. Other that the type of material used, setting of machine, processing parameters also influence the effect of the quality of moulded parts. However, most the previous researchers only focused on the impact of blend ratio (virgin and recycled material) on the mechanical properties of the moulded parts produced. There have been limited studies on the effect of blend ratio between virgin and recycled material on the quality (warpage) with optimal processing parameters. In this study, the existing design of front panel housing was used, Acrylonitrile Butadiene Styrene (ABS) materials widely used in the moulding industry were used to form front panel housing using existing mould. Evaluation on the performance in terms of quality (warpage) on the moulded part using R0 (100% virgin), R30 (70% virgin: 30% recyeld), R40 (60% virgin: 40% recycled) and R50 (50% virgin: 50% recycled) were conducted by simulation studies and experimental works. Next, optimisation methods were used in order to obtain the optimal setting of processing parameters to mould the plastic parts using the mixture blends of material. Response Surface Methodolgy (RSM) and Particle Swarm Optimisation (PSO) methods have been used as the optimisation methods. Results in simulation studies and experimental works of R0 indicate that there is no warpage on the front panel housing in x direction. Thus, this study only focuses on the warpage in y direction, while the warpage ib x direction is neglected. The optimised value of warpage in y direction for R0 using RSM and PSO are 0.245 mm and 0.242 mm, respectively, which improved 5.38% and 6.92% as compared to the recommended result from simulation studies, 0.26 mm. Meanwhile, the result of warpage in y direction on the front panel housing moulded by R30 is approximately 7.35% (RSM) and 8.25% (PSO) higher than R0. In addition, R30 is the best blend ratio compared to R40 and R50. The value of optimised warpage for R40 are 22.44% (RSM) and 23.98% (PSO) higher than R0. While the value of optimised warpage for R50 are 32.65% (RSM) and 33.42% (PSO) higher than R0. From the Analysis of Variance (ANOVA), the results show that melt temperature is the most significant processing parameter influencing the warpage in y direction for R0, R30, R40 and R50 mixture blends material. The findings indicate that, the quality (warpage) of the moulded parts produced using mixture blends of virgin and recycle material can be improved, thus offering more profit to the moulding industries.
