Valve Spring Production Process for Motorcycles

The valve spring serves as a vital component in the valve system of an internal combustion engine, functioning to return the valve to its original closed position and maintain an effective gas-tight sealing. This academic paper aims to examine the manufacturing and production process of compression springs at PT. Trijaya Sukses Sejahtera, focusing on the critical stages of coiling, annealing heat treatment, grinding, oiling, and rigorous quality control. The research methodologies applied throughout this study include literature study, direct empirical observations during practical internship activities, and detailed interviews conducted with company representatives. The primary raw material utilized in this process is specialized SWOSC-V steel wire, a high-strength alloy steel with excellent fatigue resistance. The production sequence begins with precision spring winding using an advanced CNC coiling machine, followed by an annealing heat treatment conducted at 400°C for 8 minutes to effectively relieve internal residual stresses. Furthermore, grinding is meticulously performed to flatten spring ends to achieve a highly precise final length of 38 ± 0.5 mm, while an oiling process is subsequently carried out to prevent surface corrosion and significantly extend service life. Strict quality control protocols are systematically implemented to carefully inspect dimensional accuracy, mechanical strength, and visual defects. The final internship findings indicate that the initial accuracy of the mechanical coiling process greatly determines the ultimate spring quality, whereas operational defects occurring during the grinding stage remain the primary cause of Not Good (NG) products. With proper standard operating procedures and continuous quality supervision, these manufactured springs consistently meet automotive industry standards and perform optimally under very extreme working conditions.