K omet Indonesia is a company that specialize in pla stic industry. Since it was first established in 1986, it has been striving to persi stently improving its quality while maintaining its cost of production as low as possible . The intention of this is not only fo!\" company profit , but it is also the company \'s mission to satisfy the customer\'s requirement on the quality of a plastic product so that its product can compete in the market. As a result of this, it is the objective of the company to make some improvements on the quality of its product, be sides the capability process in its production is low.With regard to this, some analysis and investigations have been done to identifythe major problems and types of deficiency of the current product, discover the optimum setting that leads to the improvement of the quality of the product, and then implement & analyze it in the real practice .The result of the investigations showed that the difference in the weight and thediameter of the product could happen due to the setting of the machine that is not optimum or not according to the standard. In adjusting the machine setting, Komet Indonesia has been using the conventional method, trial-and-error, which is based on its experience gained during all the years of operations. Not only some investigations and analysis have been done so far, but some experiments and data collection have also been done to improve its quality. The experiment s were done based on three factors: temperature, pressure, and speed. Each one of them consists of two levels. After some data have been gathered, the next steps are to calculate: Measurement System Analysis (MSA), Statistical Process Control (SPC), Capability Process, Design of Experiments , and Multi Response Surface Method.It was also discovered that the major types of defect include: color is notdistributed evenly; product is out of shape; and cracks are found in some parts of a unit. Moreover, temperature and pressure were found to be the most significant factors that can influence the quality of a product. Hence, the optimum setting obtained was found out to be 300°C (temperautre) and 74% or 1270 kgf/cm2 (pressure) with the speed was maintained from its original setting: 70 mm/s. From this optimum setting, there has been an increase in the process capability : the weight increases 83.61% from 0.61 to1.12 and the diameter increases 98.11% from 0.53 to 1.05.