The influence of helix angle of router bits on chip flow, roughness and noise level in milling different grain angle orientation of teak wood

This study was done to investigate surface roughness, noise level, chip shapes and chip flows characteristic in milling teak wood by conventional and helical router bits. Down-milling process compared to up-milling process produced better surface roughness, lower noise level, and flow chip. Better surface roughness (R-a value) was produced by the router bits with higher helix angle compared to lower helix angle. Noise level decreased with increasing in the helix angle of the router bits. The increasing in the angle of the wood grain would increase the values of surface roughness and noise level. With increasing helix angle of the bits the amount of spiral and flow chips increased and granule chips were reduced. The investigations have clearly confirmed that the helical edge is considered to be a valuable design to improve upon the performance of the straight edge for wood milling applications.