INTERRELATION BETWEEN INTERNAL BOND, DENS ITY DISTRIBUTION AND ULTRASONIC VELOCITY OF PARTICLEBOARD

For predicting Internal Bond (IB) of particleboards two different non- destructive testing methods were applied. Density profile and ultrason ic velocity perpendicular to the board surface were determined on pane ls from industrial production. Characteristic values were calculated f rom the density profile. They usually show higher correlations to the IB than the mean density. The characteristic value for the area around the minimum density (RohMin4) shows the best correlations with the IB . Ultrasonic velocity however shows the highest correlation coefficien ts with the IB (0.70 less than or equal to r less than or equal to 0.9 8). IB can be predicted with high reliability by multiple correlation using the ultrasonic velocity and the characteristic value RohMin4. Th e relationship between the results of non-destructive testing and IB d epends on type and thickness of the board as well as of various proces sing parameters.