%0 Research article
%T Operational efficiency and damage to sawlogs by feed rollers of the harvester head
%A Nuutinen, Yrjö
%A Väätäinen, Kari
%A Asikainen, Antti
%A Prinz, Robert
%A Heinonen, Jaakko
%D 2010
%J Silva Fennica
%V 44
%N 1
%R doi:10.14214/sf.165
%U https://silvafennica.fi/article/165
%X In mechanical cutting, deep damage caused by feed rollers can reduce the  yield of good quality timber for the sawmill and plywood industries.  Additionally the feeding and energy efficiency of feed rollers are  important for the profitability of harvester cutting. The objectives of  this study were to compare the damages to sawlogs, as well as the time  and fuel consumption of stem feeding with six different steel feed  rollers during the processing of stems using a single grip harvester.  This study tested two rollers with big spikes, two rollers with small  spikes, one roller with studs in v-angle and one roller with adaptable  steel plates in the ring of the roller. A highly detailed, and accurate  processing and fuel consumption projection was recorded using the  harvester’s automated data collector on a log and stem level. The roller  adaptable plate averaged, for unbarked sawlogs, the lowest damages of  3.7 mm. While the damages of the roller with big spikes were the deepest  with an average of 7.8 mm. For medium stems, volume of 0.35 m3, the  range of differences between the maximum and minimum effective feeding  time per roller was 6–19%, which would increase the effective time  consumption of cutting by 1–3%. Corresponding differences in fuel  consumption during total stem processing were in the range of 7–15%.  According to this study it can be concluded that the traditional rollers  with spikes were most effective in processing and fuel consumption, but  at the same time they caused the deepest damages to the sawlogs. The  roller type with adaptable steel plates was the most effective for small  stems, additionally it also caused the least damage to the sawlogs.