Selection of chipper engine size based on business scale and optimised cost of chipping and transportation

Abstract

ABSTRACTThe best chipper engine size was obtained by optimising the chipping operation according to business scale and transportation cost. The total chip supply cost could be reduced by improving the rate of machine utilisation of chippers. From regression analysis, the engine power of chippers expressed well the chipping and transportation costs, and the trade-off relationship between these costs was proved by the model supply chain in Iwate Prefecture, Japan. The chipper with a middle-sized engine, with an engine power of 200–400 kW, was the best choice in the perspective of economy and transportation management while the business scale needed to be at least 20,000 solid m3 year−1. The total supply cost by a chipper with a smaller engine was not the best but it could be recommended to attract small-scale companies that produce less than 10,000 solid m3 year−1. Chippers with a larger engine could be introduced if the business scale was about 50,000 solid m3 year−1. However, even if the chipping cost could be reduced, the supply chain would require larger trucks or trailers on such a large business scale. The shuttle transportation system needs to be improved to reduce the unloading time that occupies one-fifth to one-fourth of a cycle time and empty drives.