Three- dimensional (3D) printing as an emerging disruptive technology to manufacture new goods based on wood waste from local sources in a circular economy framework

To support the European Union (EU) Action Plan for Circular Economy, a set of successful three-dimensional (3D) printed demo cases is required for boosting multi-stakeholder incubation processes and supporting knowledge and tools (business models, legal and commercial agreements, successful case studies with time-lines, do’s and don’ts, etc). As a relevant indicator obtained in 2019 from the implementation progress of the EU Action Plan for Circular Economy, it highlights that comparing the number of 2012 jobs associated with the sectors involved with the circular economy compared to 2016, there is an increase of 6% (around 4 million jobs generated). In addition, it underlines that new business models have emerged and developed new markets within and outside the European Union space. Using 2016 again as a reference, the repair, reuse, and recycling activities generated an added value of 147 billion euros representing an investment volume of approximately 17.5 billion euros. However, how should a region address 3D printing technologies as an emerging disruptive technology to manufacture new goods from local sources in a circular economy framework? It has been found that not all regions have a strategic document regarding the implementation of the circular economy. In addition, the regions that own them can be classified by strategy, road map, and action plan. Thus, to answer this question, the region needs to understand the concept of Circular Economy and the development of strategic documents (strategies, roadmaps, action plans) for their proper application according to the characteristics and resources. In this vein, the manufacture of wood-based furniture by using the 3D printing technique, as aimed in the INEDIT project, is selected in this work as a route to accelerate the development of the circular bio-economy in Galicia/Spain. Wood as a building material is chosen because it is the only building material able to store CO2 instead of producing it since large quantities of biogenic carbon are embedded in the wood raw material. In fact, 1m³ of the wood has a global warming potential above -600 kg CO₂e. In addition, according to “A cadea forestal-Madeira de Galicia 2017”, Galicia represents 47% of total wood production in Spain, 1.9% of roundwood generated in the EU-28, and more than 3.5% of that obtained in the eurozone. To maximise the benefits, the proposed value chain is based on an innovative process that provides a double approach to sustainability: first, the conversion of wood waste mixture which can be derived from wood waste rejected by other processes, which in turn is biodegradable; and secondly, 3D printing technique is considered a zero-waste manufacturing technology. 3D printing helps cut costs, optimise production and increase environmental performance by using only the exact amount of material needed, including biomaterials. As a key indicator, using 3D printing meant construction material usage was cut by 30 to 60% and costs by half. Other relevant benefits are identified:

• Local production: instead of manufacturing the components at one location in the world and then shipping them around, they can be printed close to the customer, saving on emissions and transportation energy. Only digital files (3D CAD files, STL, GCode., etc.) and instructions for processing the wood beams and wood waste (sawing, conditioning, pretreatment, dispersion into polymeric matrices, etc.) are “crossing borders” in this process. Besides saving on transportation, it also creates local jobs.
• Remove waste: by working additively, you only use the material you effectively need for the final geometry, instead of starting from a larger billet. There is also less machining afterward, so less wasted material.
• Design freedom: With the design freedom that 3D printing offers, it is possible to design and create complex components, only applying material there where it is useful. Lightweight designs equal less material usage.
• Material characteristics: it is possible to create flexible and stiff characteristics with one material by modifying the geometry. This integration of functionality and parts minimises the number of materials used and eliminates fastening methods like bonding or screwing. This makes recycling easier and more effective.
• Recycling: 3D prints the product, use it and after its economic use take it back and reform the part into new material for new designs that can be printed again. However, SMEs companies must overcome many difficulties. These include among others the need for successful environmental and technical criteria to evaluate the development of initiatives; system-wide evaluation of performance; SMEs involvements despite possible constraining economic gains; bridging the physical material and energy flow analysis to the analysis of the economic effects; and a need for more data to improve local sources detection. On the other hand, there are many economic drivers in view of changing economic conditions in the EU and worldwide such as the volatility of resource pricing; the high prices of emerging technologies; etc. In addition, companies face challenges in commercialising the solution due to a lack of regulatory standards and the designers’, project developers’, and owners’ skepticism about the products’ safety.