Prediction model for the pressing process in an innovative forming joints technology for woodworking

Abstract

To improve the efficiency of the joints formation, a new method of pressing in the longitudinal direction is proposed. This paper presents a predictive model for the pressing force depending on the state of the wood and the parameters of the pressed mortise. The most significant factors are the width of the mortise and the moisture content of the wood. Interestingly, the depth of the mortise formation is a less significant factor, which means that the pressing technology will allow to form a long glue line and accordingly high joint strength due to sufficient profile length. In the test range of factors, the best results in terms of energy costs are shown by a minimum mortise width of 4 mm. Further research should be devoted to the study of the formation of small width mortises (4 mm or less) and the investigation of their quality.

Modeling and multicriterial optimization of the mortise forming process in pine wood blanks

“…The aim of optimization was to find modes that ensure high quality processing with minimal energy consumption. Therefore, to develop the objective function, the previously obtained models (2), (3) for predicting F e , h 3 [12,14] were also used:…”

“…The punch has a profile with rectangular tenons and, in the process of intrusion into the butt-end of the workpiece, forms rectangular mortises [11,12]. The pressing technology allows to ensure high accuracy of the dimensions and shape of the mortises [12], to obtain a joint with a sufficient length of the glue line and, accordingly, high strength [10,14], to eliminate the appearance of waste in the form of chips [11], using a simple design, inexpensive and durable tool [12].…”

“…These include the dimensions of the formed mortises and the characteristics of wood blanks. In particular, for the same wood species, it's will be the moisture content [12,14]. The main output parameter is the pressing force as an energy-power indicator of the process.…”

“…The main output parameter is the pressing force as an energy-power indicator of the process. The methodology and results of the search for a predictive model for determining the pressing force, denoted as F e , were given earlier in the study [14]. To determine rational technological modes, it is also necessary to take into account the quality indicators of the formed rectangular mortises.…”