Cutting forces and noise in helical planing black spruce wood as affected by the helix angle and feed per knife
Paul Wellenreiter, Roger E. Hernández, Claudia B. Cáceres, Carl Blais
Abstract
A conventional straight knife cutterhead and three helical knife cutterheads were tested for planing black spruce wood (Picea mariana (Mill.) B.S.P.). Effects of helix angle and feed per knife (FK) on maximum cutting forces and sound level were evaluated. A 3-axis dynamometer and an array microphone were used to simultaneously record the forces and the sound level, respectively. Parallel (FP), lateral (FL), resultant (FR) forces, and sound level increased as FK increased. Helical tools produced lower FP, positive and negative normal forces (FNP and FNN), and FR. Parallel forces tended to decrease as helix angle increased at high FK (4.7 mm). Differences among helical tools were not significant for normal and resultant forces. Cutterheads with the two highest helix angles (50° and 60°) produced higher FL at low (1.3 mm) feed per knife. Impacts of these cutting forces on the production of surface defects and ways to reduce them were discussed. Helical cutterheads considerably generated lower sound pressure level, with a maximum difference of up to 11.5 dB(A).