Effect of Hardwood Sawmill Edging and Trimming Practices on Furniture Part Production
In a recent edging and trimming study at three hardwood sawmills, it was observed that the lumber volume produced was approximately 10 percent less than would be necessary to make the most valuable lumber. Furthermore, the excess portion of wood that was removed from the edging and trimming process contained a large percentage of clear wood. In light of rising costs and increasing environmental concerns, the option of producing furniture parts from unedged and untrimmed boards is explored. This research investigates the potential furniture part yields from unedged and untrimmed boards compared to both optimal and actual edging and trimming practices. The resulting volume of cuttings from unedged and untrimmed boards was found to be 25 percent higher than from the actual edged and trimmed lumber produced at the mills.
Optimum Edging and Trimming of Hardwood Lumber
Before the adoption of an automated system for optimizing edging and trimming in hardwood mills, the performance of present manual systems must be evaluated to provide a basis for comparison. A study was made in which lumber values recovered in actual hardwood operations were compared to the output of a computer-based procedure for edging and trimming optimization. The optimization procedure was based on National Hardwood Lumber Association grading rules and market prices for green lumber. Using a sample of 120 red oak boards obtained from three sawmills in southwest Virginia, it was found that the respective mills recovered only 78, 65, and 62 percent of the value yielded by the optimization procedure. Given the level of value recovery actually attained by sawmills, it was concluded that substantial increases in value can be expected from optimizing edging and trimming. Other aspects of interest were investigated, such as the quality (grade) of lumber that benefitted most from optimization, the effect of volume loss on value recovery, and the relative impact on lumber value if each operation were optimized independently of each other.
Does gang ripping hold the potential for higher clear cutting yields
Abstract : Cutting yields from gang ripping hardwood lumber graded by the National Hardwood Lumber Association standard grades are determined using the technique of mathematical modeling. The lumber used is the same as that in an earlier mathematically modeled determination of cutting yields from traditional rough mill procedures. Mechanical cutting factors such as kerf, cutting lengths, and minimum salvage size are also the same in both studies. A comparison of yields between the two systems is made. While gang ripping produces higher total yields in all grades, the gain tends to be in the medium and shorter cutting lengths. (Author)