The effect of raw material, cut length, and chip discharge on the performance of an industrial chipper

In this study we examined the effect of specific factors on chipper performance by using a mobile industrial chipper in a real-life commercial setting. The comprehensive experimental design consisted of five replications per each combination of two types of raw material, two chip discharge systems, and two cut lengths (i.e., 5 × 2 × 2 × 2 = 40 replications). Each replication consisted of a full 18-m3 trailer load. Cut length was manipulated by using different drum types. When all else was equal, the doubling of cut length resulted in a 50 percent increase of average chip length, a 15 percent increase of net productivity, and a 15 percent decrease in fuel consumption. The handling characteristics of the raw material had a strong impact on chipper productivity', causing variations on the order of 20 percent. The discharge system had no significant effect on fuel consumption or productivity, but it did impact product quality and bulk density. Using a blower allowed increasing bulk density between 4 and 7 percent, whereas the installation of a belt conveyor reduced the incidence of small chips and fine particles by up to 30 percent.