The focus of this paper is to establish a characterisation method for seven polyamide (PA) grades to determine the major material to manufacture an automotive worm gear. The composite properties were measured according to the worm gear loadings: tensile strength, Young's modulus, abrasion and impact resistance. They were also correlated to the PA moisture absorption and its glass fibre (GF) reinforcement. The data from mechanical tests were applied in the finite element analysis (FEA) using the von Mises stress criterion. Before the rig tests of the PA worm gears, the injection process was evaluated, through the capillary rheometry. A higher difficulty to process PA 6/6 30% GF was found, due to its lower apparent viscosity. In the end, the influence of moisture absorption was as decisive to the gear's material selection as the GF to the pinion. Thus, the PAs with the best performance were: PA 6 with 30% GF (gear) and with PA 60% GF (pinion).

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International standards and original equipment manufacturers (OEM) procedures usually define wear tests in organic materials focusing on the brake lining temperature. The current work presents an approach combining different brake pads temperatures, vehicle speeds, and brake pressures for analyzing their effects and interactions in the friction material wear through dynamometer tests. Therefore, mechanical properties were evaluated, where internal shear strength had the most significant influence on wear; furthermore, compressive strength and flexural strength did not considerably change with variations on the test parameters. A 23 factorial design of the experiment (DOE) showed that the brake temperature alone was not the main factor for increasing wear, and the primary wear mechanism was abrasion. Furthermore, higher vehicle speed (80 km/h) along with greater brake pressure (3 bar) promoted the highest friction material mass loss (10.8 g).

This work analyzes the application of surface treatment of plasma nitriding with post-oxidation applied to injection mold extractor pins to reduce the injection cycle's interruptions for mold lubrication. For that, a device that simulates the operation of the injection mold extraction system was created. Wear was evaluated by mass loss and dimensional variation of the extraction pins and their bushings. The samples were characterized by microhardness and X-ray diffraction (XRD). The wear mechanisms were identified by scanning electron microscopy (SEM) and the coefficient of friction was analyzed employing a ball-on-plate tribological test. The results showed that the proposed system with plasma nitriding and postoxidation meets the requirements with a lubrication interval twice as long as the current system.

O presente trabalho tem por objetivo, a deposição de filmes finos de DLC sobre componentes do sistema extrator de moldes de injeção, verificando a influência deste revestimento superficial no desgaste desses componentes, sob diferentes configurações de lubrificação superficial. Para esta avaliação, pinos extratores, atualmente produzidos em aço AISI H13 e nitretados à gás, foram revestidos com um filme fino de DLC (carbono tipo diamante, do inglês Diamond Like Carbon) e buchas extratoras foram confeccionadas em AISI P20 e AISI H13, e, posteriormente, temperadas e revenidas. O filme fino de DLC foi depositado em uma câmara com sistema PECVD (deposição química a vapor assistida por plasma, do inglês Plasma Enhanced Chemical Vapor Deposition) auxiliado por confinamento eletrostático de plasma. Um dispositivo que simula o sistema de extração de um molde de injeção foi utilizado para testar o comportamento ao desgaste dos conjuntos pino-bucha propostos, em função do aumento do número de ciclos.  O desgaste nos pinos foi avaliado quantitativamente por perda de massa, após 100.000 ciclos. Os resultados da perda de massa mostram que para as amostras sem utilização de graxa lubrificante, a taxa de desgaste foi consideravelmente menor. Os pinos que menos apresentaram desgaste foram os dos conjuntos PS e HS, ambos sem utilização de graxa, com perda de 5,400 e 5,467 mg, respectivamente. Com isto, ficou evidenciado a possibilidade de utilização de pinos com revestimento de DLC sem a utilização de graxa lubrificante em sistemas extratores de moldes de injeção e que isto ainda propiciou uma redução considerável na taxa de desgaste.

Additive manufacturing, specifically 3D printing (3DP), is a trend of great relevance in industry 4.0. The objective of this work is presented as a systematic review of the available literature to define the main methods and standards towards analyzing the material properties, 3D printing filament extrusion variables, and polylactic acid (PLA) recycling. The research used the methodology of a mixed explanatory sequential review based on studies already published in books and journals.  These data have relevant information to serve as a guide for the recycling, extrusion, and 3D printing of the PLA.