Analysis of selected functional parameters of saw chains

Results obtained from the research study focused on the functional parameters of five saw chains tested on a test bench equipped with an electrically driven chain saw brought a number of findings. One of the most important of them is the significant difference between the cutting rates of round and square chains. The cutting rate of square chains R = 27.9 cm2.s-1 is about 12% higher than the cutting rate of round chains. The influence of the chain construction on the chain cutting rate was conclusively demonstrated - the cutting rate of chains with a square profile is higher than the cutting rate of round-profile chains. It was further found out that although the specific energy Em = 77.8 Ws.cm-2 is by ca. 7% lower in the square chain than in the round chain, Student's t-test did not reveal any statistically significant difference in the data on the specific energy consumption of round and square chains, i.e. the influence of the chain design on the specific energy consumption of the chain at cutting was not clearly demonstrated. Other findings, for example, showed that working with a loose saw chain on the guide bar impairs parameters of the chain operation or that energy demands of cutting with the saw chain are directly proportional to wood density (hardness) and increase with the decreasing wood moisture. Yet another finding was learning the energy flow structure, which indicated that 46% of total power input is consumed by the electric motor alone for its operation while only about 7% goes for driving the chain movement along the bar (without cutting) and power input required for cutting is approximately 46%.