Efficacy comparison of two methods for determining the position of the rebate edge (formed after MDF machining) during automatic monitoring of workpiece delamination

Abstract

: Efficacy comparison of two methods for determining the position of the rebate edge (formed after machining) during automatic monitoring of workpiece delamination. Delamination is one of the most common defects in the processing of wood-based materials. It has a huge impact on the quality of the final product. In order to determine the delamination indicators in a simple and reliable way, the automatic image processing method can be used (Śmietańska et al. 2020). Bator and Śmietańska (2019) proposed the special algorithm to estimate the straight line representing a milling edge. However, this algorithm is quite complicated. The aim of this article is to check whether the aforementioned (complicated) algorithmic way can be replaced by a much simpler idea – the precise manual positioning of the scanned sample on the scanner (using very simple device installed on the scanner). The special experimental research was carried out to compare the effectiveness of the two different methods. The straight line which represents the rebate edge identified by Bator and Śmietańska (2019) algorithm was usually accurate to 1 pixel (0.02 mm). The analogue line based on the assumption that the scanned samples were perfectly positioned on the scanner only sometimes fit just as well. At worst, the distance between these lines is 0.2 mm. Usually the distance did not exceed 0.16 mm but was significant and quite random. There was no statistically significant correlation between this parameter (Dmax) and tool condition (VB). It means that sample were not perfect positioned. They were placed more or less in the same position because of imperfect stiffness of the frame installed on the scanner and human errors.