The aim of the project was the development of an electroforming process for the production ofrnmedical implants out of gold. To prove the applicability of this technology, tympanostomy tubesrnwere chosen as demonstrators.rnThese barbell-shaped tubes are usually produced mechanically; of silicone or, for higherrntherapeutic demands, of metal – gilded silver or gilded stainless steel. Gold electroforming of therntubes as an alternative manufacturing process would reduce the expenditures for the mechanicalrnpreparation and lower the corrosion susceptibility significantly.rnTo obtain electroformed gold tubes of the desired shape, the following steps are necessary:rnfabrication of a negative template by drilling holes with countersinks in an insulated aluminiumrnsheet, electroforming process, removal of the aluminium by using a sodiumhydroxide solution.rnFor the optimisation of the shape and surface quality of the tubes respectively the simplificationrnof the manufacturing process, various parameters were tested, e.g. Aluminium quality and sheetrnthickness, type of insulation layer, substrate processing, hydrodynamic conditions, type ofrnelectroforming electrolyte, electrodes position, etc.rnThe manufactured tubes were characterised in view of thickness distribution, hardness, surfacernroughness and purity in comparison to mechanically produced reference tubes.rnFrom the results obtained during the project it can be concluded that electroforming processesrncan be easily adopted for the manufacture of medical implants. The time-consumingrnelectroforming process is by far compensated by the simultaneous production of an arbitraryrnnumber of implants.
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