MANUFACTURING GEARBOX HOUSING CASE MADE OF CARBON FIBER REINFORCED POLYMER COMPOSITE BY AUTOCLAVE METHOD

The aim of the study was to verify the possibility of reproducing a steel, welded gear body element, using an epoxy-carbon composite, as an adaptation project. The content includes a description of the design and manufacturing process along with an indication of the problems occurring at various stages. The design procedure included product optimization, mold design, and composite structure design. The molded element was to be a composite monolithic structure and was intended for vibroacoustic studies. The wall thickness of the element was to be 6-10 mm. Pre-impregnated fabric (so-called prepreg) with an areal mass of 240 g/m(2) (outer layers) and 800 g/m(2) (structural layers) was used as the material. The matrix was epoxy resin. The technological procedure included producing the mold and molding the product using the produced mold. The mold was made by milling with a 5-axis milling center (CNC), based on a block assembled of epoxy panels. The molding of the product was started by manually lining the mold with a layup of prepregs. During laying, consolidation was carried out several times using a vacuum bag. A full vacuum packet (vacuum foils, breather, delamination fabric) was applied to the layup. The preformed layup was cured in an autoclave at 120 degrees C, at the pressure of 4 bar and a set -1 bar vacuum inside the packet. The total process time was 4 hours. It was found that the obtained product very accurately reproduces the steel housing and meets the assumptions of the comparative element for vibroacoustic testing. The use of the composite allowed the weight of the element compared to the original to be reduced by over 80% without taking into account the weight of additional steel elements necessary for installation and by over 60% including the weight of those elements. The performed procedures and their effect confirm that polymer matrix composite materials are very well suited for reproducing products and creating prototypes.