Studies on a measurement method of surface roughness in wood machining I. Ehe effect of stylus types on the roughness profiles

A measurement method of surface roughness was investigated by using spruce and sassafras sanded by abrasive papers of grit # 60, 240 and 1000. A stylu s instrument with a cone type of stylus with tip radius of 5, 250, and 800 mu m, and an axe type of stylus with tip radius of 5 mu m were used to meas ure the roughness profile on spruce, and the roughness profile and center l ine average roughness (R-a75) on sassafras. The roughness profile of spruce distinguished differences in roughness due to the different grit numbers o f abrasive paper when the cone type of stylus with tip radius of 5 mu m was used. The roughness profile of sassafras was affected by it's anatomical s tructure when the cone type of stylus with tip radius of 5 mu m was used fo r the surface sanded by the abrasive paper of grit #1000. The effect of rou ghness due to the anatomical structure was reduced for the cone type of sty lus with the tip radius of 250 mu m, and was small for the cone type of sty lus with the tip radius of 800 mu m and the axe type of stylus with the tip radius of 5 mu m on sassafras. The roughness profile drawn by the axe type of stylus with the tip radius of 5 mu m expressed more clearly the differe nce of the surface sanded by the abrasive paper of grit # 60, # 240 and #10 00 than that by the cone type of stylus with the tip radius of 800 mu m on sassafras. The value of center line average roughness (Rn,,) and its scatte r were decreased with increasing tip radius of the cone type of stylus on s assfras, and were lowest for the axe type of stylus among the styluses inve stigated. The effect of the anatomical structure on the roughness profile o f planed surfaces was reduced when the axe type of stylus was used.