neobjavljeni prilog sa skupa
Additive manufacturing enables production of complicated geometries in a short time. With the possibilities of creating internal or external mesh structures and obtaining less mass while maintaining good mechanical properties, additive manufacturing has great advantages of being used in the automotive industry. Ceramics, metals, polymers, and composites can be used in additive manufacturing, whereby in this paper the emphasis is on polyamide reinforced with carbon fibres. Composite materials are one of the most common materials in the automotive industry, since in conditions of elevated temperatures they enable the achievement of much better properties. This paper describes the application of carbon fiber-reinforced polyamides for the production of a cylinder housing of the experimental internal combustion engine by additive manufacturing with fused deposition modeling – FDM. The Hatz 1D81 engine was modified and converted into an experimental engine for research of advanced combustion processes. Due to the high temperatures developed during its operation, the cylinder needs to be cooled. Standard Hat cylinder is made of gray cast iron and is air cooled. For research purposes liquid cooling could enable better cylinder temperature stability. The question arises whether the classic metal cylinder of the air-cooled engine can be upgraded to water cooling with addition of polymer housing made by the additive manufacturing process. To make this possible, a polymer housing with cooling channels was designed to fit the engine cylinder and made using a fused deposition modeling process with hexagonal internal infill on the Makerbot Method X Carbon Fiber Edition 3D printer. To ensure a good seal, a material addition for subsequent turning processing was left on the models, i.e. the number of external contours during production was increased to 5 contours. Due to the high temperatures on the inner walls of the cylinder (~ 180°C), polyamide reinforced with carbon particles was chosen for production of housing. Vicat softening temperature after annealing in an oven for 5 h at the temperature of 80 °C showed that PA6-CF has a shape retention (dimensional stability) temperature of 188 °C, while PA12-CF has a shape retention at the temperature of 170 °C. The cylinder housing was made with both of the two materials mentioned, although PA12-CF has a lower shape stability temperature than the one developed in the engine. This shortcoming was tried to be eliminated with the change of processing parameters such as higher infill density from 30% to 50% compared to PA6-CF. Due to the housing height of 160 mm, the housings were made with a layer thickness of 0.3 mm and the production took 22 h for PA6-CF and 24 h for PA12-CF. The mass of the manufactured PA6-CF housing is 370 g, while for the PA12-CF is 380 g because of the higher infill density.
additive manufacturing; composite materials; cylinder housing; design; engine
Razvojem virtualizacijskih tehnologija raste kompleksnost IT sustava, dok korisnici istovremeno zahtijevaju brži pristup resursima, napredne integracije i jednostavnost korištenja. Jedno od ključnih rješenja za ove izazove primjena je…
Ovaj rad istražuje i uspoređuje mogućnosti prosljeđivanja grafičkih kartica na Hyper-V i KVM hipervizorima prema virtualnim strojevima, detaljno opisujući metode, postupke i razlike u arhitekturi koje utječu na…
The ever-growing usage and adaptation of HTTP/3 in web traffic leverages Quick UDP Internet Connections (QUIC) as a transport protocol. QUIC is widely recognized for reduced latency, enhanced…