A Comparison of Four Techniques For Producing High-Grade Furniture Core Material From Low-Grade Yellow-Poplar

Four methods of converting low-grade yellow-poplar lumber into highgrade furniture core material (lumber core) were compared. High-grade core material is used in tops, shelves, doors, and drawer fronts and only minor defects are allowed. Three gang-rip first and the conventional crosscut-first manufacturing sequences were evaluated in combination with 1 Common, 2A Common, and 2B Common lumber. Results based on costs and yields indicate that 2A and 2B Common lumber and either of two gang-rip first techniques would be the most effective choices. INTRODUCTION Crosscut-rip I In this traditional method, the lumber is skip N RECENT YEARS, yellow-poplar lumber has planed and then crosscut to required lengths (Fig. become abundant, especially in the lower grades. 1). The crosscut saw operator uses a back-gage in Because of this increase in availability and current deciding where to cut a board to the required lumber costs, the continued use of yellow-poplar length while maximizing usable material. Ranas furniture core material would be assured if the dom-width cuttings are ripped from the cut-tocurrent cost of lumber core could be maintained length boards. Pieces containing defects are sent or lowered. Achieving this goal requires the use of lowgrade lumber in combination with an efficient low-cost manufacturing technique. Failure to do this would result in the loss of the furniture core market to particleboard, fiberboard, and other substitute materials. Core panels are used as center fill material for laminated products. High-grade lumber core cuttings—such as those used in tops, shelves, doors, and drawer fronts—can contain only minor defects such as stain, small bird pecks, small burls, pin knots, and pinworm holes. In this study, I attempted to determine the most efficient techniques for producing furniture core from low grades of yellow-poplar. In actual cutup tests or through computer simulation, I compared the following manufacturing sequences: Ž Crosscut-rip • Gang-rip crosscut • Gang-rip longest length • Gang-rip finger joint. In all tests I used kiln-dried 4/4 yellow-poplar lumber in grades 1 Common (l C), 2A Common (2AC), and 2B Common (2BC). In making the comparisons, I also considered the: • Optimum ripping width when gang ripping • Costs for lumber, transportation, drying, handling, rough milling, and overhead • Ease of manufacture and the frequency of operator error. Figure l.-Crosscut-rip manufacturing sequence.