Production of 3D Parts from Wood Chips in a Closed Mold Process

Abstract

The application-oriented distribution of wood chips is a major obstacle in the production of 3D molded composite parts made of plastics and wood. Similar to fibers in conventional fiber-reinforced plastic components long chips can be used for force transmission. Short chips and wood powder can be distributed homogeneously between longer chips to increase the wood volume percentage and to allow post-processing-free edge areas. The applied process parameters during the incorporation of the matrix material determine the filling of the cavity and the impregnation of the chips. Different formaldehyde-free resin and adhesive systems, as well as thermoplastic powders are used as matrix material. By controlling the subsequent pressing process of the oriented and impregnated chips the density and wall thickness of the molded part can be influenced. In this work different production process variants and a concept for a modular 3D experimental mold are investigated. The flowability and bulk density of the wood chip fractions are characterized and the compression pressure required in the production process is determined. Initial tests with a panel mold are carried out and the bending strength of the manufactured specimen is examined.

Numerical Simulation of the Deformation Behavior of Softwood Tracheids for the Calculation of the Mechanical Properties of Wood–Polymer Composites

“…Wagenführ also describes how new types of hybrid composites with outstanding material properties can be produced through particle decomposition, press treatment and hybridization of wood, and emphasizes that it is advantageous to preserve the cell structure of the wood as far as possible and to view the wood cell microscopically as a fiber composite material [7]. To implement this recommendation, this publication uses numerical simulation methods for filament wound hollow profiles to model the compaction deformation behavior of tracheids to estimate achievable mechanical properties of highly densified, elongated softwood particles such as veneer strips and OSB strands, which are already used successfully to manufacture wood-polymer composites (WPC) [8,9].…”