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PurposeThe paper examines the work and interactions of staff councils in German municipalities and the power resources the staff councils have at disposal. The paper also discusses the relationship between staff councils and trade unions and suggests a modification of the prominent concept of the “dual system of interest representation” to a “trimorphic system of interest representation” for the public sector.Design/methodology/approachThe paper draws on case studies of staff councils in municipalities and administrative districts, relying on semi-structured interviews, group discussions and document analysis.FindingsStaff councils operate in an extensively regulated field. The major task of staff councils is to monitor that employers follow collective agreements and the law. Staff councils' existence and co-determination rights of staff councils are provided by law; however, staff councils not only use institutional, but also organisational and – occasionally – political power resources, whereas structural and societal power resources are rarely actively used. The relationship between staff councils and trade unions often plays an important role and is in many cases characterised by mutual support.Originality/valueAlthough staff councils are a widespread and a very interesting type of representation because staff councils represent both employees and civil servants who are employed in two distinctly different employment systems, staff councils are widely under-researched. This paper enriches empirical knowledge about labour relations and introduces the notion of a “trimorphic system of interest representation”.

Polymers have a reputation for several advantageous characteristics like chemical resistance, weight reduction, and simple form-giving processes. The rise of additive manufacturing technologies such as Fused Filament Fabrication (FFF) has introduced an even more versatile production process that supported new product design and material concepts. This led to new investigations and innovations driven by the individualization of customized products. The other side of the coin contains an increasing resource and energy consumption satisfying the growing demand for polymer products. This turns into a magnitude of waste accumulation and increased resource consumption. Therefore, appropriate product and material design, taking into account end-of-life scenarios, is essential to limit or even close the loop of economically driven product systems. In this paper, a comparison of virgin and recycled biodegradable (polylactic acid (PLA)) and petroleum-based (polypropylene (PP) & support) filaments for extrusion-based Additive Manufacturing is presented. For the first time, the thermo-mechanical recycling setup contained a service-life simulation, shredding, and extrusion. Specimens and complex geometries with support materials were manufactured with both, virgin and recycled materials. An empirical assessment was executed through mechanical (ISO 527), rheological (ISO 1133), morphological, and dimensional testing. Furthermore, the surface properties of the PLA and PP printed parts were analyzed. In summary, PP parts and parts from its support structure showed, in consideration of all parameters, suitable recyclability with a marginal parameter variance in comparison to the virgin material. The PLA components showed an acceptable decline in the mechanical values but through thermo-mechanical degradation processes, rheological and dimensional properties of the filament dropped decently. This results in significantly identifiable artifacts of the product optics, based on an increase in surface roughness.

Additive Manufacturing (AM) as much as sustainability aspects gained increasing attention in the last couple of years. The vision of resource-efficient manufacturing at batch size one is often claimed as an outstanding property of AM. Fused Filament Fabrication, as one of the most used AM technologies, satisfies this statement only in a restricted sense, through simple handling for non-experts and low-cost materials and machines. Next to performance-driven and process-influencing attributes, the question of a general ecological improvement through thermo-mechanical recycling rises. Therefore, recycling options of the thermoplastics are mandatory to explore. Based on the ISO 14040/44 Life Cycle Assessment (LCA) methodology two different geometries were environmentally assessed during a primary process cycle, using, and recycling. Each geometry was manufactured by a bio-based polymer and internationally produced (PLA) and petroleum-based locally produced polymer (PP) with a corresponding support filament. The methodological approach demonstrates an option how to evaluate the field of AM and recycling regarding environmental aspects. Furthermore, an adaption of the sensitivity towards industrial parameters (material/energy efficiency) showed an ecological benefit concerning recycling.