Part receiving scheduling for a truck manufacturing company

Abstract

Truck manufacturing industry is one of the most important industries in Thailand. This industry impact to not only national economy but also an employment rate. Nowadays, a number of truck manufacturers (small, medium and large sizes) tend to increase which result in a higher competitive environment. Every manufacturer should improve their operation so as to be able to compete in an efficient way. Generally,each truck comprises of a large number of parts with many sizes. So, part receiving is the important process both part receiving planning and daily part receiving scheduling. If part receiving scheduling is not appropriate managed, there will be large number of supplier’s trucks waiting at a stop point in front of a warehouse which is very hard to control. Moreover, this waiting can delay other supplier delivery schedules. From data collection, it is found that, in a case study company, an averaged waiting time of supplier’s trucks is equal to 1,409 minute. This research aims to study and improve part receiving scheduling method for a case study company. The objective is to reduce total waiting time of part suppliers. The experiment is conducted to test an efficiency and effectiveness of 5 scheduling rules (Current Order(CO), Longest Processing Time(LPT), Shortest Processing Time(SPT), Lowest Standard Deviation(LSD) และ Highest and Lowest Standard Deviation(HLSD)). In this experiment, the part supply data in Monday which is the heaviest traffic day. It is found that the Lowest Standard Deviation (LSD) method result in a schedule with the lowest total waiting time. With LSD method, a total waiting time is reduced from 1,909.1 minute to 3.0 minute which is equal to 99.84% and the maximum waiting time is reduced from 94.1 minute to 4.3 minute which is equal to 95.43%.