Reduction of waiting and throughput times of cement trucks in cement-loading processes generally requires additional input resources, such as cement-loading machines and operators. However, a superfluous number of input resources can increase idle time. On the other hand, minimizing input server resources can significantly save costs for cement plants, but would result in excessive waiting time and throughput time of trucks, limiting the number of trips that trucks could travel to transport cement. To maximize the utilization of cement trucks and input resources, a trade-off between truck waiting time and server idle time is necessary. This study developed a simulation model maximizing the utilization factor of truck waiting time and machine idle time. By using EZStrobe software, the current operations of the cement-loading process were simulated based on data obtained between August 2012 and June 2013 at Asia Cement Plant, Thailand. The results show that a new design of operations with alternate layout, which operates by using four regular cement-loading channels with two extra channels during the 8-hour peak duration, is recommended for the cement-loading process to optimize performance, since they reduce truck waiting time, throughput time, and queue length, with the lowest machine idle time possible.
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