Publicação
Evaluation of subtractive microtechnologies for injection micromoulding
| Resumo: | The development of new microsystems is highly dependent on manufacturing technologies that can economically produce microparts without defects in large production runs. In this context, microinjection moulding of polymer materials emerges as one of the most capable techniques for serial micromanufacture. In the mouldmaking industry, the term micromanufacturing refers to the generation of high precision three-dimensional (3D) microstructures using a variety of materials and microtechnologies. The late century saw extremely small feature sizes being produced relying on techniques, like etching and lithographic technologies. However, some of these microtechnologies lack the ability to produce complex 3-dimensional shapes with high-quality surface finishing. These limitations result from the critical dimensions up to which the surface structure at the microscale can be manufactured with good performance. Besides the creation of 3D microstructures with high aspect ratio, the achievable accuracy, the surface texture and integrity and the possibility to produce microdetails are also a challenge in micromachining. In this work, the performance of the main micromachining techniques used for creating 3Dstructures at the microscale in injection moulding blocks are discussed, evaluated and compared. In particular, laser beam machining, mechanical micromachining, electro-discharge micromachining and electron beam machining were considered. These techniques were used to produce moulding blocks for microparts that were injection moulded in polypropylene and polyacetal. These blocks were assembled in injection moulds specifically designed and manufactured for this study. |
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| Autores principais: | Selada, António Cordeiro Baptista |
| Ano: | 2011 |
| País: | Portugal |
| Tipo de documento: | tese de doutoramento |
| Tipo de acesso: | acesso restrito |
| Instituição associada: | Universidade do Minho |
| Idioma: | inglês |
| Origem: | RepositóriUM - Universidade do Minho |
| Resumo: | The development of new microsystems is highly dependent on manufacturing technologies that can economically produce microparts without defects in large production runs. In this context, microinjection moulding of polymer materials emerges as one of the most capable techniques for serial micromanufacture. In the mouldmaking industry, the term micromanufacturing refers to the generation of high precision three-dimensional (3D) microstructures using a variety of materials and microtechnologies. The late century saw extremely small feature sizes being produced relying on techniques, like etching and lithographic technologies. However, some of these microtechnologies lack the ability to produce complex 3-dimensional shapes with high-quality surface finishing. These limitations result from the critical dimensions up to which the surface structure at the microscale can be manufactured with good performance. Besides the creation of 3D microstructures with high aspect ratio, the achievable accuracy, the surface texture and integrity and the possibility to produce microdetails are also a challenge in micromachining. In this work, the performance of the main micromachining techniques used for creating 3Dstructures at the microscale in injection moulding blocks are discussed, evaluated and compared. In particular, laser beam machining, mechanical micromachining, electro-discharge micromachining and electron beam machining were considered. These techniques were used to produce moulding blocks for microparts that were injection moulded in polypropylene and polyacetal. These blocks were assembled in injection moulds specifically designed and manufactured for this study. |
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