THE INFLUENCE OF CUTTING-BILI.J REQUIREMENTS ON LUMBER YIELD USING A FRACTIONAL-FACTORIAL DESIGN PART II. CORREI-JATION AND NUMBER OF PART SIZES

Abstract. Cutting-bill requirements. among other factors. influence the yield obtained when cutting lumber into parts. The first part of this 2-part series described how different cutting-bill part sizes. when added to an existing cutting-hill. uffect lumbcr yield. and quantified these observations. To accomplish this. the study employed linear least squares estimation technique. This second paper again looks at the influence of cutting-bill requirements but establishes a measure of how preferable it is to have a given part size required by the cutting-bill. The influence of the number of different part sizes to be cut simulta-neously on lumber yield is also investigated. Using rip-first rough mill simulation software and an orthogonal. i W- II fractional-factorial design of resolution V, the correlation between lengths, widths. and 20 part sizes as defined by the Buehl;;'ann cutting-bill with high yield was established. It was found that. as long as the quantity of small parts is limited. part sizes larger than the smallest size are more positively correlated with high yield. Furthermore. only 4 out of the 20 part sizes tested were identified with having a significantpositive correlation with above average yield (65.09/jd. while 10 were found with a significant negative correlation and above average yield. With respect to the benefit of cutting varying numbers of part sizes simultaneously, this study showed that there is a positive correlation between yield and the number of different part sizes bein