Development of a measuring system to determine particle dimensions

Background and Objective

Depending on the technology applied, wood particle dimension measurement in the context of process control and optimization is less meaningful, incomplete or very time-consuming. The sieve analysis provides a combined characteristic of  dimension and shape, which is referred to as particle size. The two-dimensional, image-analytical measurement of put down particles is limited to particle length and width, the measurement in free-falling particles (2D and 3D) is differently precise depending on the particle orientation to the camera. Although the three main geometric particle axes can be determined with manual caliper measurement, this method is labour-intensive, time-consuming and has limited reproducibility. Since the particle geometry has a significant influence on the panel properties and thus on the possibility of process optimization, the "3D-Span" project intends to develop an image analysis system for the automated, three-dimensional determination of wood particle dimensions and a technique for taking samples.

Target Group

Wood-based panel industry

Approach

A laser profile scanner is to be used to measure the wood particles. It records a digital height profile of the particles separated on a conveyor belt. In contrast to the use of a line scan camera, the particle thickness, surface area and volume can be determined in addition to particle length and width. On the basis of this data, various characteristics are calculated with which particles can be characterized and compared. The functionality of the measuring device is to be tested and its suitability for process optimization is demonstrated by the experimental measurement of various particles. A reproducible sampling, which is also developed within the scope of the project, is important for a high selectivity of the measuring instrument.

Our Research Questions

The Thünen Institute is interested in finding out how reliably and precisely the measuring device developed determines the particle dimensions. This is particularly true with regard to sampling. The basic question is whether the new technology can be used to increase material and energy efficiency in particleboard production and thus conserve resources.