Alternative materials in moulding elements of hybrid moulds: structural integrity and tribological aspects

• Autor(a) principal: Martinho, Pedro
• Data de Publicação: 2021
• Outros Autores: Pouzada, António Sérgio
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.8/8264
• topic: Structural simulation; Ejection force; Shrinkage; Polypropylene; Vacuum casting; Rapid tooling; Injection moulding; Hybrid mould

Hybrid moulds are an increasingly considered alternative for prototype series or short production runs. This type of tools resorts on the use of Rapid Prototyping and Tooling (RPT) to produce the moulding elements (blocks or other inserts). This study was developed using a hybrid injection mould with exchangeable moulding elements that were produced by additive manufacturing (AM), namely vacuum epoxy casting, stereolithography and ProMetal. A full steel tool was also used as a reference. The processing conditions for the polypropylene moulded parts using the hybrid mould were monitored for pressure, temperature and ejection force. The hybrid mould performance was assessed in terms of pressure and temperature evolution during the injection cycle and the AM moulding elements for physical integrity. The data from the polypropylene moulded parts and the moulding inserts are compared with structural and rheological simulations using ANSYS Workbench and MOLDEX 3D. The results show that the hybrid mould performance and the structural integrity of the moulding elements depend on the properties of the materials used. The moulding shrinkage, when resin cores are used, is also affected by the core deformation caused by the injection pressure.