The 4 th TSME International Conference on Mechanical Engineering 16-18 October 2013, Pattaya, Chonburi AMM1046 Improvement of Computer Numerical Control Machining Process to Reduce Cycle Time of The Water Pump Body Nuttapol Limjeerajarus 1, *, Patcharawat Charoen-amornkitt 1 , Kotchakarn Nantasaksiri 1 and Vitayakorn Khanviboon 2 1 Research Center for Advanced Energy Technology, Faculty of Engineering, Thai–Nichi Institute of Technology 1771/1 Pattanakarn, Suan Luang, Bangkok 10250, THAILAND 2 Engineering machining department, Asahi Tec Aluminium (Thailand) Co.,ltd. 361 Moo 1, Rattanaraj Rd., Bangbor, Bangbor, Samutprakarn 10560, THAILAND *Corresponding Author: Email: nuttapol@tni.ac.th, Tel.: +66-2763-2600 Ext. 2920, Fax.: +66-2763-2600 Ext. 2900 Abstract In 2012, Thai automotive industry growth rate increased greatly as high as the 1 st rank among the global ranking. Therefore, to serve such enormous customer demand, automotive manufacturers need to adapt themselves to increase their effectiveness and performance in manufacturing process. From the study of the manufacturing process of the water pump body at Asahi Tec Aluminium (Thailand) Co., Ltd., which is one of the most important aluminium automotive parts manufacturers in Thailand, it was found that the machining process is the most time-consuming process with the longest cycle time. In order to reduce the cycle time of the whole manufacturing process to increase the production capacity, Japanese philosophy called “Kaizen” and production line balancing, which can be done with minimal modification and investment, were applied. The original cycle time of the machining process was 2.58 min but after the improvement in computer numerical control (CNC) machining process by reducing wasted time and modifying machine tools, the new cycle time decreased for about 33 percent. As a result, the production capacity increased by 50 percent for which the company could satisfy the increasing customer demand and also the annual operating cost would be reduced for about 1,200,000 baht without any negative effect on the quality of the product. Keywords: Kaizen, CNC, Cycle time, Water pump body, Automotive parts manufacturing 1. Introduction Automotive industry is the main industry in Thailand which accounts for more than 12% of Thailand’s GDP [1]. In 2012, Thai automotive industry growth rate increased greatly as the first rank among global ranking, and became the 9 th biggest automotive producers in the world, as compared to the 15 th in 2011 [2]. The adaptation of automotive manufacturers is needed to increase their production capacity. Typically, this can be done by increasing production lines, however, the current domestic employment minimum wage, which is raised greatly by the government policy, would be its major obstacle