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Thermoplastics processing usually involves the non-uniform cooling of molten polymer, which results in the presence of residual stresses in the final product. The magnitude of these stresses can be high enough to induce severe shape changes in the product, as well as changes in the overall material performance. Because of this, it is important to be able to accurately predict and measure them. In this study, the effect of coupling a kinetic model of crystallization on the prediction of thermal and pressure-induced residual stresses using the residual temperature field and formation pressure concepts is investigated. In addition, the effect of packing pressure on the deflection of injection molded polymer plates after ejection is reported. Simulation results were compared with experimental data, and it was found that considering crystallization in the prediction of residual stresses decreased the % error between predicted deflection and experimental results, from 0.52–7.34 to 3.0–56.3%. Also, good agreement between experimental results and the simulations performed using the residual temperature and pressure fields concepts in 2D while including a kinetic model of crystallization with different packing pressures. [ABSTRACT FROM AUTHOR]

ABSTRACT: The versatility of plastic materials allows engineering components of very complex geometries and functionalities to be injection molded from them. Because the manufacturing cost of a mold increases with the complexity of the cavity, it is important to optimize the design of component and mold concurrently. In this study, a methodology for determining the optimum parting direction (PD) considering mold‐manufacturing factors such as tool accessibility and the amount of material to be removed is presented. The methodology starts with an accessibility analysis in which a three‐dimensional part is discretized, and candidate PDs are selected based on maximizing the accessible area, that is, the area that can be machined with a single workpiece orientation or setup. Then, the rough machining process is considered, and an optimum PD that minimizes the rough machining time for both the cavity and core plates is selected. The methodology is applied to four different automotive components: a mirror cover, an interior panel, a pillar, and a fender splash shield. [ABSTRACT FROM AUTHOR]

• Recycled polyvinyl butyral reduces wear of glass fiber reinforced polyamide. • Recycled polyvinyl butyral reduces friction coefficient of polyamide composites. • Recycled polyvinyl butyral behaves as a solid lubricant in polyamide composites. The current global environmental situation makes plastics' recycling necessary. In this work, the effect that adding recycled polyvinyl butyral (r-PVB) from laminated safety glass on a glass fiber reinforced polyamide (PA-GF) has on its tribological performance is investigated, to envisage potential new applications for r-PVB. PA-GF blends containing 10%, 15%, and 20% of r-PVB were obtained by melt-mixing and injection molding. Pin-on-disc tests were performed with a normal load of 10 N, sliding speed of 0.5 m/s, track diameter of 15 mm, and sliding distance of 500 m. A reduction between 9 and 13% for the coefficient of friction, and of 38–50% for mass loss, was found when r-PVB was added to the matrix, indicating that r-PVB might be acting as a solid lubricant. SEM images showed that r-PVB reduced fiber fracture and promote the formation of a transfer film that reduced the contact between the polymer composite and the steel ball. [ABSTRACT FROM AUTHOR]