Microfabrication of PDMS based microfluidic devices involves fabrication of micromolds which need expensive infrastructure, such as clean room, photolithography equipment, photoresists, substrates, masks etc. In this paper, we present fabrication of micromolds using three dimension (3D) printing for soft lithography [1, 2]. By employing 3D printing technology overcomes the challenges posed by time consuming and difficult to manufacture, with state of the art 2-D MEMS fabrication technology [3]. Compared to the conventional method of microfabrication, 3D printed mold can be processed more rapidly, augment use of materials, intricate design which is challenging by photolithography [4,5]. Here, we designed and fabricated micro features using binder jetting printer (Objet30 Pro) and photopolymer jetting printer (Formlabs Form 2). Objet30 Pro uses the technique of depositing adhesive liquid onto the powder photopolymer on the build tray. Binding process between the powdered particles make a solid structure. During the printing of master no support structures where used. The master was also printed using the deposition of photopolymer using the Formlabs Form 2 printer. Concept behind the fabrication is curing the photopolymer by UV light which is deposited pointwise layer-by layer. Since, the fabrication of the master is done in slices the surface of the master was rutted which gave bumpy replication but, were able to print the feature (Round trench, Hexagonal trench) size of 200μm (Fig 1 and 2). Mold fabricated using the Objet30 pro printer gave fine structures with resolution of 300μm in depth and feature size of 500μm were printed flawless. This technique forms a 3D printed structure by holding the particles and does not require support structure.

References:

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2. Khosla, A. (2011). Micropatternable multifunctional nanocomposite polymers for flexible soft MEMS applications (Doctoral dissertation, Applied Science: School of Engineering Science). http://summit.sfu.ca/item/12017
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