Patent Number: 6,293,152

Title: Method for determining twist potential in wood

Abstract: A method for determining twist potential of wood is described. One embodiment of the method comprises nondestructively obtaining a grain angle of wood, such as trees or lumber, and then determining twist potential of the wood based on the grain angle. Where the wood comprises lumber, grain angle determinations typically are made on at least one major surface of the lumber. The method typically comprises determining grain angle at at least two measuring locations separated by a predetermined distance, such as at substantially one-foot intervals along the board. The method also can further comprise obtaining at least one fiber dive angle. Particular embodiments of the present invention determine grain angle using infrared radiation, microwave radiation, light energy (such as by using a laser), electricity, ultrasound energy, and combinations thereof. Working embodiments of the method used light energy and ultrasound energy to determine grain angle. For example, a first transmission speed of an ultrasound pulse through the board was determined along a first path and along a second path. Grain angle was then determined by comparing the first and second transmission speeds. Plural grain angles also can be determined using this ultrasound method. Twist potential can be correlated to empirically determined twist angle. The method of the present invention provides can determine twist potential that correlates with empirically determined twist potential with an R.sup.2 value of at least 0.50.

Inventors: Stanish; Mark A. (Seattle, WA), Floyd; Stan L. (Enumclaw, WA), Cramer; Steven M. (Lodi, WI)

Assignee: Weyerhaeuser Company

International Classification: G01N 29/44 (20060101); G01N 29/07 (20060101); G01N 29/36 (20060101); G01N 29/04 (20060101); G01N 29/42 (20060101); G01N 33/46 (20060101); G01N 033/46 (); G01N 029/00 (); G01R 027/26 ()

Expiration Date: 09/25/2018