Design and construction of a profile density measurement system for the composite wood products industry

The authors discuss the profile density measurement system (PDMS), an instrument that can determine profile density quickly and easily using gamma-ray density-measurement techniques. They discuss design techniques used in precision gamma-ray instruments, construction difficulties, and mathematical methods used to interpret the data. The PDMS has proven to be a useful quality-control instrument for the hot-pressed-panel industry. One prototype and 5 second-generation units have been built. All have an excellent reliability record. The major advantages of gamma-ray profile-density measurement for hot pressed panels are: (1) the sample is not destroyed; (2) the results are highly repeatable; (3) the result are in computer form, and thus, two samples or a sample and a standard can be compared accurately; (4) gamma-ray cross-sectional density measurement is much faster than with manual methods; and (5) application of simple image-processing techniques to the PDMS will allow the system to do a better job of analyzing the edges of hot pressed panels as well as allowing for more detailed analysis of laminated material