Towards rapid 3D direct manufacture of biomechanical microstructures
King, Philip Huw (2009) Towards rapid 3D direct manufacture of biomechanical microstructures. PhD thesis, University of Warwick.
WRAP_THESIS_King_2009.pdf - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Official URL: http://webcat.warwick.ac.uk/record=b2339630~S15
The field of stereolithography has developed rapidly over the last 20 years, and commercially
available systems currently have sufficient resolution for use in microengineering applications.
However, they have not as yet been fully exploited in this field. This thesis investigates the
possible microengineering applications of microstereolithography systems, specifically in the
areas of active microfluidic devices and microneedles. The fields of micropumps and microvalves,
stereolithography and microneedles are reviewed, and a variety of test builds were fabricated
using the EnvisionTEC Perfactory Mini Multi-Lens stereolithography system in order to define its
A number of microneedle geometries were considered. This number was narrowed down using
finite element modelling, before another simulation was used to optimise these structures. 9 × 9
arrays of 400 μm tall, 300 μm base diameter microneedles were subjected to mechanical testing.
Per needle failure forces of 0.263 and 0.243 N were recorded for the selected geometries,
stepped cone and inverted trumpet. The 90 μm needle tips were subjected to between 30 and 32
MPa of pressure at their failure point - more than 10 times the required pressure to puncture
average human skin.
A range of monolithic micropumps were produced with integrated 4 mm diameter single-layer 70
μm-thick membranes used as the basis for a reciprocating displacement operating principle. The
membranes were tested using an oscillating pneumatic actuation, and were found reliable
(>1,000,000 cycles) up to 2.0 PSIG. Pneumatic single-membrane nozzle/diffuser rectified devices
produced flow rates of up to 1,000 μl/min with backpressures of up to 375 Pa. Another device
rectified using active membrane valves was found to self-prime, and produced backpressures of
up to 4.9 kPa.
These devices and structures show great promise for inclusion in complex, fully integrated and
active microfluidic systems fabricated using microstereolithography alone, with implications for
both cost of manufacture and lead time.
|Item Type:||Thesis or Dissertation (PhD)|
|Subjects:||T Technology > TS Manufactures|
|Library of Congress Subject Headings (LCSH):||Microlithography, Microfabrication, Microfluidic devices, Microinjections|
|Official Date:||December 2009|
|Institution:||University of Warwick|
|Theses Department:||School of Engineering|
|Supervisor(s)/Advisor:||Covington, James A., 1973-|
|Sponsors:||Engineering and Physical Sciences Research Council (EPSRC)|
|Extent:||xxiv, 234 leaves : ill., charts|
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