Fabrication and Design of a Nanoparticulate Enabled Micro Forceps

Abstract

A novel fabrication process and design optimization method for a micro forceps is presented. This work is part of a larger research effort to design and fabricate nanoparticulate enabled surgical instruments. The micro forceps is a monolithic compliant mechanism that due to its two-dimensional design can be manufactured using the new fabrication process. The process begins with fabrication of an array of molds on refractory substrates using a modified UV lithography technique. In parallel, engineered ceramic nanocolloidal slurries are prepared for gel-casting into the molds. Mold infiltration takes place via a squeegee technique adapted from screen printing with excess slurry removed using an ethanol wipe. Finally, the photoresist molds are removed with a reactive ion etch (RIE) step, and ceramic parts sintered to full density. Employing this manufacturing technique for the compliant micro forceps design is advantageous because a large number of parts can be produced with a large aspect ratio (≥40:1), sharp edges (∼ 1 μm), and a resolution of 2 μm. Two optimization problems are formulated to determine the effect of dimensional parameters and material strength on the performance of the compliant micro forceps. First, performance is sensitive to small changes in the geometry, indicating that dimensions and shrinkage rates must be carefully controlled during processing. Second, performance can also be improved by using very large aspect ratios and/or improvements in material strength. A sample part manufactured using the new process is presented.