Search

As a contribution of recycling of polymers in the automotive industry, recycled polyvinyl butyral (rPVB) from automotive windshields is being explored as a solid lubricant reinforcement for improving lubricity of engineering polymers. This work aims to evaluate the tribological behavior (coefficient of friction [CoF] and wear resistance) of polyamide 6 (PA6) and glass-fiber-reinforced polyamide 6 (PAGF) blended with rPVB as solid lubricant under two-body and three-body abrasive conditions. The different polymer blends were produced by adding recycled polyvinyl butyral (rPVB) into a matrix of either a commercial polyamide 6 (PA6) or a commercial 30% glass-fiber reinforced polyamide 6 (PAGF). The tribological tests were conducted in an instrumented microabrasion tester for generating wear and measuring the coefficient of friction (CoF) in both dry and microabrasion conditions. In the dry condition, rPVB was effective in reducing the CoF for both PA6 and PAGF. Two-body abrasion was found as the predominant wear pattern in the dry condition. On the other hand, in the microabrasion condition, the additions of rPVB were not totally effective since they produced a wear resistance increase for PAGF but a reduction for PA6, which was ascribed to a notable decrease in toughness for PA6 when adding rPVB. Well-defined plowing traces and several SiC particles embedded in the scars were the predominant patterns in all the materials. In both PA6 and PAGF, CoF increased with the rPVB additions. [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]

Abstract: A reverse analysis of the Vickers indentation fracture toughness was carried out to derive a numerical expression for estimating the fracture resistance of the Fe2B layer. The boride layers were created at the surface of AISI 1018 borided steels by the paste boriding process, in which a 4-mm-thick layer of boron carbide paste was applied to the material surface. The treatment was carried out at temperatures of 1123–1273K with exposure times of 4, 6 and 8h at each temperature. From the set of experimental conditions used in the boriding process, Vickers indentations were performed with an applied load of 1.96N at 25μm from the surface of the borided steels. The crack lengths created from the corners of the Vickers indentation prints were analyzed in the Palmqvist crack regime. The numerical expression of the stress intensity factor (K) of the Fe2B layer was assisted by both a dimensional analysis and the superposition principle. The analysis considered the residual stress field generated by the indentation load, which was superimposed upon different crack lengths; the stress intensity factor was expressed as a function of the elastic–plastic properties of the layer, the dimensionless crack length, and the location on the Palmqvist crack front. From an extensive numerical analysis, the results of the fracture toughness (K C) values of the Fe2B layer were estimated with the finite element method, and then compared with the values obtained by traditional Palmqvist crack models proposed by other researchers. [Copyright &y& Elsevier]

Plastic recycling in the automotive industry is a priority. In this study, the effect of adding recycled polyvinyl butyral (rPVB) from automotive windshields on the coefficient of friction (CoF) and specific wear rate ( k ) of a glass-fiber reinforced polyamide (PAGF) is investigated. It was found that, at 15 and 20 wt.% of rPVB, it acts as a solid lubricant, reducing CoF and k up to 27% and 70%, respectively. Microscopical analysis of the wear tracks showed that rPVB spreads over the worn tracks, forming a lubricant layer, which protects the fibers from damage. However, at lower rPVB content, fiber damage cannot be prevented as the protective lubricant layer is not formed.