A dimensional comparison between embedded 3D-printed and silicon microchannels

J O'Connor,J Stafford,N Jeffers,J Punch

doi:10.1088/1742-6596/525/1/012009

J O'Connor, J Stafford + Show 2 more

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https://doi.org/10.1088/1742-6596/525/1/012009

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Abstract

The subject of this paper is the dimensional characterization of embedded microchannel arrays created using contemporary 3D-printing fabrication techniques. Conventional microchannel arrays, fabricated using deep reactive ion etching techniques (DRIE) and wet-etching (KOH), are used as a benchmark for comparison. Rectangular and trapezoidal cross-sectional shapes were investigated. The channel arrays were 3D-printed in vertical and horizontal directions, to examine the influence of print orientation on channel characteristics. The 3D-printed channels were benchmarked against Silicon channels in terms of the following dimensional characteristics: cross-sectional area (CSA), perimeter, and surface profiles. The 3D-printed microchannel arrays demonstrated variances in CSA of 6.6-20% with the vertical printing approach yielding greater dimensional conformity than the horizontal approach. The measured CSA and perimeter of the vertical channels were smaller than the nominal dimensions, while the horizontal channels were larger in both CSA and perimeter due to additional side-wall roughness present throughout the channel length. This side-wall roughness caused significant shape distortion. Surface profile measurements revealed that the base wall roughness was approximately the resolution of current 3D-printers. A spatial periodicity was found along the channel length which appeared at different frequencies for each channel array. This paper concludes that vertical 3D-printing is superior to the horizontal printing approach, in terms of both dimensional fidelity and shape conformity and can be applied in microfluidic device applications.

Highlights

Industry has benefited greatly from the introduction of microfluidic technologies including thermal management, biotechnology, and health care
The vertical 3D-printed channel produced good shape conformity and lends itself to microchannel manufacture when compared to the horizontal printing approach
The cross-sectional area (CSA) of the vertical channels were consistently less than the nominal dimensions due to curvature present at corners

Summary

Introduction

Industry has benefited greatly from the introduction of microfluidic technologies including thermal management, biotechnology, and health care. When developing microfluidic devices or structures, a number of different channel manufacturing techniques exist for both thermal management and Lab-on-a-chip(LOC) applications. Chemical etching of Silicon wafers using deep reactive ion etching (DRIE) or wet-etching techniques (KOH) is the conventional method of channel fabrication. Anodic bonding is used to create a permanent seal between a glass slide and the Silicon wafer [2]. In LOC applications, Polydimethlysiloaxane (PDMS) or Poly(methyl methacrylate) (PMMA), casted from a Silicon mold, is the conventional method of microchannel fabrication and was initially demonstrated by Martynova et al.[3]. The channels are sealed by bonding the microchannel to a glass slide using PDMS or some other Silicone based polymer.

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