PLA² fArMing: Additively manufactured PLA-continuous fibre reinforced PLA-composites for rural farming

keywords: additive manufacturing, 3D-printing, material extrusion, life cycle assessment, analysis of recycling potentials, farming, CAD, FEM analysis, UN sustainable development goals, close-loop, continuous fibre reinforced composite, biopolymer

As a response to the TU call for Pro Sustainability projects at TU Berlin, PLA² fArMing aims at addressing the United Nation's (UN) Sustainable Development Goals (SDG) with the 4 goals: No poverty, No hunger, Health and Welfare, Sustainable Consumption/Production. This is achieved through the application-oriented use of biopolymer composite (PLA fibres in PLA filament) in 3D printing along with emphasis and investigation on recyclability and life cycle analysis. This sustainable cooperation project consists of an international cluster of expertise with two faculties from TU Berlin, Fraunhofer IAP, Uppsala University (Sweden) and Michigan tech (USA).

Summary

In this project, a new type of mono-material combination with numerous application possibilities, social relevance and great potential with regard to sustainable application is being developed. Concrete product designs using this technology are developed during the project, with the focus being explicitly on usability and needs on-site as well as circular economy aspects. Scientific added value is created through the mechanical analysis of a new mono-material composite, which is underpinned experimentally and by model-building.

Whether the use of biopolymers will contribute to a more sustainable society is a question that will have to be studied by a representative life-cycle analysis (LCA) of each application and by comparison with existing applications. Representative LCAs are needed at material and product levels. They must make allowance for future developments in biopolymers and take account of all relevant environmental impacts associated with the complete product life cycle. This includes the depletion of raw materials, the agricultural use of fertilizers and pesticides, transportation, utilization, and waste disposal.

Aim

The central goals of this cooperation project are the production of a mono-material composite from PLA for 3D printing and the reliable prediction of its mechanical properties using analytical and numerical methods. A special focus is placed on the use of the mono-material for small-scale farming equipment.

Project

In this project, the mechanical properties of 3D-printed structures made of PLA continuous fiber-reinforced PLA filament are investigated analytically with the help of computer modeling and numerical analysis which is thereafter compared with the experimental results. The fiber is made from an LPLA-DPLA stereo complex (scPLA) with greater rigidity than the filament and a higher melting temperature. The printed structure therefore only contains PLA and can consequently be easily recycled to pellets or to re-extruded filament for 3D printing. Thus, this innovative mono-material combination offers great potential for the transfer of research work.

Important research questions

• Process optimization in the fibre extrusion and characterization of the Stereo-PLA fibre
• Production of the test-specimen from two different polymer manufacturing processes
• Characterization of the mechanical behaviour of PLA-PLA composite in 3D printing
• Modeling of the 3D printed fibre reinforced structure
• Research with regard to the SDGs

Numerous SDGs are addressed through the application orientation of the project with specific usage intentions and the corresponding cooperations, but also through the emphasis and investigation of recyclability and biocompatibility of the raw materials used. Over 70 percent of all people worldwide with food insecurity live in rural areas, the majority of them in smallholder and subsistence farming conditions [1]. By optimizing individual tools that can be manufactured on site, a contribution is made to improve living and working conditions in the short and medium term.

The SDGs and how this project addresses them

SDG 1 No poverty:

Lowering the running costs of maintaining subsistence agriculture frees up more resources for self-sufficiency and for the community.

SDG 2 No hunger:

Better use of the dwindling labor force in rural areas can increase yields and improve food security. On-site repairs/replacements using additive manufacturing reduce the dependency on manufacturers and lead time, potentially saving entire harvests.

SDG 3 Health and Wellbeing:

The improvement of physical working conditions through the availability of innovative and individual tools in the agricultural sector can contribute to the well-being of countless small-scale farmers.

SDG 12 Sustainable consumption / production

The special focus on life cycle analyzes and recycling concepts ensures that the entire development process, from use to recycling, is captured by sustainable product development. In addition, needs analysis ensure that no product is created that is not needed. This avoids unnecessary use of resources.

[1] FAO, “The State of Food and Agriculture” Food and Agriculture Organization of the United Nations (FAO), Rome, 2014