การลดของเสียในกระบวนการผลิตชิ้นงานความเที่ยงตรงสูงโดยใช้หลักแนวคิดของลีน กรณีศึกษา : บริษัท อาร์แอนด์ดี พรีซิชั่น จำกัด

R & D PRECISION CO.LTD manufactures various types of work. Yet there were defects of work in previous working and the company was unable to deliver products to customers as required and some might have been destroyed. As the information referred to the waste detected each month from January 2014 to June 2014 it is found that the volume of defect rate was 9.56 percent resulting in losing cost of production and other business opportunities. This research aims to reduce waste in the production of high precision with lean concepts. The study starts from the analysis of employees working information by creating a value stream mapping. The study found that cylindrical grinding takes the longest time. Then the study explored and determined the root cause of the problem by using a Pareto Diagram together with a Fish-Bone Diagram to analyze the minor causes. It is found that most wastes are caused by measuring control especially for the work that has a shaft hole with thickness of 2.25 mm. Thus the study and experiment were conducted to determine the flow rate of the coolant for the work piece in the cylindrical grinding machine and a fixed value is the rate of decreasing the size of work speed of stone wheel and work type of coolant and type of grinding stones. The goal is to reduce waste by not less than five percent and to improve the process of reducing waste effectively which will affect the environment having lesser wastes from production. It also supports competitiveness and rapid change of industry manufacturing highprecision parts in the future even better.