Experimental assessment of hybrid mould performance

Hybrid moulds are a novel approach for rapid tooling of injection moulds that combines conventional machining for the mould structure and rapid prototyping techniques for the moulding blocks (core and cavity). In this study, two routes were used for producing the moulding blocks: selective laser sintering of stainless steel-based powder (hard tool) and epoxy resin vacuum casting (soft tool). The experimental work was based on a complex tridimensional commercial part. Themouldings were made in polypropylene, and the processing performance was monitored online in terms of pressure and temperature at the impression. The performance of the moulding blocks was analysed in terms of thermal and cycle performance and structural integrity. The epoxy tooling route is more adequate for fine detailing than selective laser sintering but is not adequate for parts with extensive ribs or deep bosses. The structural integrity of the less costly epoxy composite can be compromised during ejection, this suggesting the need to evaluate the stress field by simulation at the design stage of the mould.Fundação para a Ciência e Tecnologia (FCT) - POCT

Disquieting uncertainty. Three glimpses into the future

Abstract The article sketches three major realms - the realm of world order, the realm of work, and the realm of social policy - that will in all likelihood undergo fundamental change in the years and decades ahead, raising deeply unsettling questions about their future. The account is framed by the concept of global modernity, which, while not spelled out in detail, guides the presentation of data and other secondary materials in the aim to demonstrate connections between, and, at least to some extent, common roots of, phenomena and developments that might otherwise appear to be quite disparate. The author does not present any solutions for the problems and challenges discussed in the article, but hopes to sensitize readers to their urgency and to stimulate fruitful ideas for what will ultimately have to be a collective endeavor involving not only scholars from around the world but also the general public