The primary purpose of this study was to evaluate short length lumber (less than 8 feet long) utilization opportunities within the furniture and cabinet industries. In the first part of the study a data bank of mapped red oak lumber was used to search for differences in lumber characteristics between lumber length groups. The same data was used to evaluate opportunities for improving the value of a piece of lumber by trimming a lower grade, longer length piece to obtain a shorter, higher grade board. The defect data indicated that wane makes up a slightly higher percentage of the total defect area for short boards than for long boards but the degree of crook deviation for short boards is significantly less than for long boards. The value improvement analysis indicated that fifteen percent of the 1 Common, and 49 percent of the 2A Common, 8 and 9 foot long boards could be trimmed to a higher grade, higher value short board.
The effect of lumber length on random width dimension yields was examined using the CORY lumber cut-up program. For 10 of the 18 cutting bill combinations examined, the regression between total yield and lumber length was significant. In the significant crosscut-first relationships total yield decreased with increasing lumber length. In the significant rip-first relationships total yield decreased as lumber length increased. The variable which showed the strongest and most consistently significant relationship to lumber length was the average volume of parts produced per furniture rough mill sawing operation; the regression of board feet per sawing operation was significantly and negatively related to lumber length in 14 of the 18 cutting bill combinations tested. Regression results indicated that as crook decreases, total cutting yield, average cutting length, part volume per sawing operation, and part value tend to increase.
Short and longer length lumber yields were also compared in mill studies. The mill studies were conducted at a crosscut-first furniture rough mill and at a rip-first cabinet rough mill. Total yield, the yield of the longest length cutting on the cutting bill, the percentage of total yield made up of the three longest length cuttings, average cutting length, and crosscut and rip saw rates were investigated. The only significant regression relationships detected were: 1 - for the crosscut-first, 2A Common analysis the percentage of total yield made up of the three longest length cuttings was inversely related to lumber length, and 2 - for the rip-first, 1 Common and 2A Common analyses the ripsaw volume throughput rate improved with increasing lumber length.
Simulation studies based on models of these same two rough mills indicated that the volume and value of parts cut from short length lumber in a crosscut-first rough mill compares favorably with the volume and value recovery obtained from longer length lumber. In the “worst case” crosscut-first production alternative the breakeven short length lumber price was only $129 less per thousand board feet than the going market price for longer length lumber. For the rip-first model the volume and value of parts produced from short lumber was only 60 percent that of the longer length lumber. The breakeven short length lumber prices calculated for this model ranged between $373 and $653 per mbf. / Ph. D.
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/39517 |
| Date | 02 October 2007 |
| Creators | Wiedenbeck, Janice K. |
| Contributors | Wood Science and Forest Products, Youngs, Robert L., Araman, Philip A., Deisenroth, Michael P., Kline, D. Earl, Lamb, Fred M., Wengert, E.M. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | English |
| Detected Language | English |
| Type | Dissertation, Text |
| Format | xvii, 255 leaves, BTD, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 26064330, LD5655.V856_1992.W532.pdf |
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