北美规格材机械分等综述

Machine Grading of Lumber in North America

规格材的机械分等方法是北美一种很重要的分等体系,即采用机械应力测定设备对木材进行非破坏性试验,按测定的木材弯曲强度和弹性模量确定木材的材质等级。用于机械分等规格材的分选参数可以因不同工厂机械的具体情况而进行调整,较目测分等更能适应现代化木材工业的发展要求。文中从分等方法的诞生、机械分等与目测分等相互关系、机械分等方法和标准、分等机构设置等方面介绍了北美规格材机械分等,在此基础上分析了中国规格材分等的现状并对中国规格材分等提出了参考建议。

Lumber grading engages in the design properties directly or in directly related to QC test levels. As one of the most important lumber grading systems in North America, machine grading does non-destructive test by stress rated machines, and then classify the lumbers into different grades according to their bending strength and the modulus of elasticity. The grading machine parameter settings vary from mill to mill, which is more efficient and flexible to modem wood industry than visual grading of lumber. This paper introduces some basic information about machine grading, such as the history of the machine grading of lumber in North America, the relationship between machine grading and visual grading, and the systems and standards of machine grading, then set up the grading agencies in North America. The authors provide some referential suggestions to China lumber grading.