Studies on the Characteristics of Wood Cutting Force of the Whole Saw-chain Used in a Chain-saw Machine (3)
Effect of Incorrectly Filed Saw-chain Tooth
1981 Volume 43 Issue 3 Pages 401-407
Details
1981 Volume 43 Issue 3 Pages 401-407
Based on the results obtained in Part 2, the effect of incorrectly filed saw chain tooth which lately has become a major point of interest among the people involved in forest operations, was investigated in this report. Taking five kinds of remodeled cutter teeth in which one of the functional factors was filed incorrectly, experiments were carried out according to a similar procedure as described before. The magnitude of the difference of cutting resistance forces between the tested cutter teeth and the standard teeth was examined. The results were as follows:
1) The relations between the velocity ratio λ and the tangential cutting resistance force FH and the normal cutting resistance force FV were expressed by hyperbolic curves same as the results obtained in the previous report.
2) The relation between the velocity ratio λ and the force ratio FV/FH which is equivalent to the angle of resultant cutting force was a straight line as shown in Fig. 7. Comparing these five regression curves it was clear that the force ratio was proportional to the velocity ratio and differed in its magnitude as shown in Fig. 8. In other words, it can be said that the type of back slope on the side plate cutting edge aggravates the worst due to incorrect filing, this followed in the order of the blunt type of the top filing angle, the blunt type of top plate cutting angle, the type of hook in the side plate cutting edge, and the type exceeding the depth gauge.
3) A similar tendency as described above can be seen in the relation between undeformed chip thickness δ and specific cutting resistance force fH and the specific normal cutting resistance force fV Above all the lattar appears clearly.
4) When a square-shaped cutter tooth is filed with a round file, other dimensions may be changed. Therefore, when cutter teeth are resharpened to maintain their original dimensions, special attention should be paid to the functional factors provided with each cutter tooth.
5) In other words, points to which special attention should be paid are the top plate cutting angle, top plate filing angle and depth gauges in that order. From the view point of proper filing method, as a matter of course, each cutter tooth on the whole saw chain must be maintained at their original dimensions.
