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To further increase the environmental potential of renewable raw materials, a new construction concept for fully recyclable bio-based wall elements assembled by additive manufacturing, called 3DP Biowall, is presented. The proposed concept considers the entire life cycle from material converting, to manufacturing and application, over to recycling and restarting a new construction phase. With the help of this method the materials are kept significantly longer in a closed material cycle, with conceptually no waste production. A fully biobased material mixture of wood particles and Biomix (sodium lignosulfonate and starch) is used. The present paper describes the basic approach, first production experiments as well as the achieved mechanical performance within compression and flexural tests performed with first test specimens. Furthermore, the potential of the closed material loop approach is assessed through an LCA and by comparing the 3DP Biowall to other well-known exterior wall systems. All production life cycle phases were regarded and experimentally investigated. The successful production tests and the achieved mechanical characteristics prove the feasibility and potential of the new approach. The performed LCA points out further optimisation potential regarding the mixture with the starch component having a comparatively high impact at the environmental footprint of the material mixture.

Coating of steel is a frequently applied approach to increase the resistance of moving machine parts towards abrasion, surface oxidation, and corrosion. Here, we show that plating circular saw blades with certain metals can help to reduce the electrical charging of wood dust during cutting, which has significant implications for occupational safety, healthcare, and lifetime of filter systems. With the example of beech wood planks, machine net energy consumption EV (J cm−3) and cumulated field strength E→V (kV m−4) as caused by electrically charged particles were compared for cutting of 10- and 20-mm deep grooves (800 mm length) using saw blades of different toothing (24, 60 teeth) and surface coating (Cu, Ag, and Cr). To ensure uniform feed per tooth (fz = 0.063 mm), saw blades were operated at different rotation speeds (4000 vs. 1600 rpm). The results demonstrate that the extent of electrostatic sawdust charging can be manipulated to a certain extent by the type of saw blade plating. Coating with chromium turned out to be most effective in shifting the electrostatic charge of the wood particles towards neutralization. Lowering of rotation speed using circular saw blades of higher toothing was an additional measure significantly reducing electrostatic charging of wood dust. Hence, cutting with a chrome-coated blade with 60 teeth can be specifically recommended as the reduction of electrical saw dust charging is not associated with higher machine power consumption.