A Design of Experiment Approach for Surface Roughness Comparisons of Foam Injection-Moulding Methods.

The pursuit of polymer parts produced through foam injection moulding (FIM) that have a comparable surface roughness to conventionally processed components are of major relevance to expand the application of FIM. Within this study, 22% talc-filled copolymer polypropylene (PP) parts were produced through FIM using both a physical and chemical blowing agent. A design of experiments (DoE) was performed whereby the processing parameters of mould temperatures, injection speeds, back-pressure, melt temperature and holding time were varied to determine their effect on surface roughness, Young's modulus and tensile strength.

High Temperature Adiabatic Heating in µ-IM Mould Cavities-A Case for Venting Design Solutions.

Micro-injection moulding (µ-IM) is a fabrication method that is used to produce miniature parts on a mass production scale. This work investigates how the process parameter settings result in adiabatic heating from gas trapped and rapidly compressed within the mould cavity. The heating of the resident air can result in the diesel effect within the cavity and this can degrade the polymer part in production and lead to damage of the mould.

A Novel Hybrid Foaming Method for Low-Pressure Microcellular Foam Production of Unfilled and Talc-Filled Copolymer Polypropylenes.

Unfilled and talc-filled Copolymer Polypropylene (PP) samples were produced through low-pressure foam-injection molding (FIM). The foaming stage of the process has been facilitated through a chemical blowing agent (CHNaO and CaCO mixture), a physical blowing agent (supercritical N) and a novel hybrid foaming (combination of said chemical and physical foaming agents). Three weight-saving levels were produced with the varying foaming methods and compared to conventional injection molding.

Distal hereditary motor neuropathy with vocal cord paresis: from difficulty in choral singing to a molecular genetic diagnosis.

Patients presenting with distal weakness can be a diagnostic challenge; the eventual diagnosis often depends upon accurate clinical phenotyping. We present a mother and daughter with a rare form of distal hereditary motor neuropathy type 7 in whom the diagnosis became apparent by initial difficulty in singing, from early vocal cord dysfunction. This rare neuropathy has now been identified in two apparently unrelated families in Wales.