Survey in the local industry
An on-line survey was carried out in the local industry, in which a total of thirteen companies participated. Key results:
- machining technology is not fully exploited with regards to micro injection moulding locally
- very small features are avoided in the design of micro injection moulded parts
- very few multi material micro parts are produced locally via injection moulding
- the most significant challenge concerning the fabrication of plastic parts at the micro level is the limited local market of micro plastic parts
- the strongest potential of multi material micro injection moulding is perceived to be in the biomedical device fabrication.
Typically polymer endoscopic lenses (for imaging, illumination and even transmission) are often fabricated using injection moulding and then assembled to a polymer housing using adhesives. In view of this, a modular endoscopic micro optical component fabricated by multi-material micro injection moulding was considered. It was designed using a number of design tools in different activities of the design cycle.
Design Synthesis: The optical component consists of a common base with three protrusions: one for the curved plano concave lens and two for the illumination windows. The optical component is housed within a threaded housing component to allow for interchangeability.
Design analysis: a filling simulation analysis was carried out on both the optical and housing component. This analysis was carried out for visualization of the flow and predictions of defects such as weld lines. Also a simulation of the thermal conditions during the filling was performed to identify post processing properties such as shrinkage and residual stress.
Design evaluation: The injection mould was design concurrently with the part and fabricated. Several moulding trials and experiments were carried out to ensure that the part produced meets the quality requirements. A Design of Experiments Approach (DOE) was also adopted to identify the effects of each process parameter on the replication of the micro features.
The final part produced after the DOE experiments were carried out. The red arrow highlights a small protruded part which is a reference to indicate the position of the objective lens.
- publication of survey results in an article in the magazine issued by the Malta Chamber of Professional Engineers
- a snippet on the THINK magazine - issue 6, published by the University of Malta - on page 21 of this magazine it is mentioned how research in the EX-MMIM project contributes to the manufacturing of micro components which can be utilized in biomedical devices
- article in the Times of Malta published on Thursday 24 April 2014
- Dr Farrugia presented a paper entitled ‘Design of an endoscopic micro optical part for fabrication with micro shot injection moulding’ at the ASME 2014 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (IDETC/CIE 2014), August 17-20, 2014, Buffalo, USA, co-authored by Ing. L Said, Dr A. Rochman and Ing. P Vella
- a half-day seminar on multi-material micro injection moulding was held on the Thursday 22 October 2015 at MCST premises in Kalkara - the seminar was addressed by a number of speakers, who treated various aspects related to high-value added manufacturing, micro fabrication and the EX-MMIM project in general.