Study On Non-destructive Testing System For Density Of Veneer Based On Beta Ray

Density of veneer is an important index which affects physical mechanics performance of veneer and overall performance of LVL. Seeking a rapidly non-destructively on-line testing way for density of veneer is an effective approach to monitoring the quality of LVL.This paper analyzes the status quo of non-destructive testing techniques home and abroad, and beta-ray is adopted to study non-destructively on-line testing of veneer density based on advanced techniques from abroad, mainly taking technical feasibility, safety and cost into account.The paper analyzes physical basis of beta-ray testing for density of veneer, thus ⁹⁰Sr-⁹⁰Y was chosen as radiation source on the ground of law of radiation and G-M tube as radiation testing apparatus. According to above research, testing circuit is designed and the whole non-destructive testing system is completed for density of veneer including thickness testing, density testing and related control units. At last, three types of veneer(Masson pine, Poplar,Larch) were chosen as objects, applying the system to measure the density of objects, meanwhile measuring the density of the same objects by traditional means, it is proved this system is feasible by comparing experiments.