μ Injection Moulding, ESR1, ESR8, ESR13. State-of-the-art. Micro injection moulding (μIM) is the key processing technology for high throughput production of micro components.
A number of polymer materials can be processed by μIM for the manufacture of high accuracy micro 3D products, exhibiting sum-mm to μm features, 1-10 μm range dimensional tolerances, and sub-μm to 10 nm surface roughness finishes9. High temperatures, injection flow rates and pressures are needed to achieve such results, making the process window more restricted when compared to conventional injection moulding, and very sensitive to process variation. In these conditions, process optimization is key in order to ensure the required product quality at the micrometre level. μIM has been optimized in order to enhance filling of micro cavities, process repeatability, venting conditions, demoulding performance, etc.
The currently existing challenge is due to the fact that all these μIM processing conditions have been investigated, analysed and occasionally optimized as separated entities, and only for selected (and different) materials. As a result, an overall optimized μIM process is still relying on demanding and time consuming experimental investigations, always based on off-line measurement. A fast direct relation between processing conditions and final product dimensional and surface characteristics based on in-line measurements has not been achieved so far. Fingerprint concept implementation.
In ESR1, ESR8, ESR13 projects, the overall optimization of the μIM process will be achieved by an innovative approach based on:
1. Implementation of a process-sensitive and representative finger print feature into the micro moulded application product design so to make the inspection efficient and effective, but limiting the required inspection effort.
2. Establishment of the relation between the micro moulded product quality parameters, the finger print quality response, and the μIM processing conditions (both inputs and outputs).
3. Implementation of a real-time inspection tool in the μIM equipment using both 3D optical microscopy and moulding parameters monitoring.
Expected progress beyond current state-of-the-art. As result of ESR1, ESR8, ESR13 projects fast and robust optimization of the μIM process and of the micro moulded products. Once optimized, the integrated product/process quality control of the μIM will maintain the realized μIM process consistently within the optimal process window and will ensure high-throughput zero-defect net-shape manufacturing of polymer micro components.
Three applications will be targeted by the ESRs to validate the fingerprint research: micro component for non-invasive brain surgery (ESR1), polymer micro optics produced by tribologically optimized properties of tool surface (ESR8), micro-needles drug delivery device using both conventional micro-injection moulding and a novel ultrasonic injection moulding technique (ESR13).