Comparison of the accuracy of two on-line industrial veneer moisture content and density measurement systems

Abstract

The accuracy and precision of moisture content (MC) and specific gravity (SG) measurements were tested on two industrial on-line measurement devices using microwave technology: the Metriguard DME 2800 and the Mecano MVA. Both devices were installed in a laboratory measurement line, and to obtain accuracy and precision of measurements, in total 137 spruce veneer sheets and 51 birch veneer sheets were tested. Before measurement, the spruce veneer sheets were conditioned to four different nominal MC classes between 4 and 16 % and birch veneers to three classes between 4 and 10 %. The veneer sheets were passed through the measurement devices three times. After measurement, the MC and SG of each veneer sheet were assessed gravimetrically. Using microwave technology the MC and SG of spruce and birch veneers can be measured with good accuracy and precision. The root mean square error (RMSE) for MC measurements of the spruce veneer sheets was 0.2 % on both devices and for birch veneers it was 0.7 % for DME and 0.5 % for MVA. The RMSE for the spruce SG measurement was 0.008 for both devices and for birch veneers it was 0.013 for the DME and 0.022 for the MVA.

Contactless moisture content measurement on green veneer based on laser light scattering patterns

“…Metriguard DME and Mecano MVA are two commercially available devices for online measurement of veneer MC by means of microwave methods. Antikainen et al (2015b) have performed the MC measurement on beech veneers using both devices and reported that both provide high accuracy of MC measurement with RMSE of less than 2% of MC on birch and spruce veneer. Indeed, microwave methods provide better accuracy of MC measurement than laser methods.…”

“…Nowadays, there are many portable devices that use electrical and microwave methods. However, the resolution is often higher than 10 cm 2 (Antikainen et al 2015b).…”