This paper will involve optimization of the parameters of the 3D printing process of ASTM D638 test samples with Polylactic Acid (PLA) to produce fixtures to support a quad bike chas-sis that supports 155 kg. The experiment measures the effects of layer height, printing rate, nozzle size and infill density on production time, weight, cost and mechanical characteristics, such as hardness, tensile strength and roughness of the surface. The findings indicate that higher layer height, speed and nozzle diameter lead to less time spent on manufacturing with the most significant effect on manufacturing time being the layer height and the speed of printing. The dimensional accuracy of specimen 1 and 6 was close to 100%. The best surface roughness was topographically at a layer height of 0.2 mm, infill density of 100, nozzle diam-eter of 0.4 mm, and a print speed of 80 mm /s. When it comes to hardness, the most positive results were reached due to a layer height of 0.08 mm and a nozzle diameter of 0.2 mm. The peak tensile strength was obtained using the layer height of 0.4 mm, infill density of 80 per-cent, nozzle diameter of 0.15 mm, and a printing speed of 120 mm/s. The originality of this assignment consists in its use in automotive engineering where specially designed 3D-printed fixtures are used instead of standard metal parts, which are lightweight and economical. This study is very insightful and can be applied to improve quality and efficiency of 3D printing in manufacturing of quad bike fittings and further include more additive manufacturing.