Improved Tube Holder for Circulating Flow Circuits: Free STL available for download

Summary

To improve the consistency of µSiM experiments involving circulating flow with peristaltic pumps, I designed a 3D-printable implement that securely holds small tubes in place. This simple design iterates on 3D printed tube holders or improvised tube holders that others have used previously. The purpose of this blog post is to share this tool with anybody intending to study pump driven circulating flow with µSiM devices.

Design Changes

The diameter of each tube slots is 8 mm wide, matching these 5 mL vials that are suitable for usage as fluid reservoirs in circulating flow experiments (Product Link, Premium Vials). A larger gap, with clearance for adhesives (i.e. hot glue) exists at the bottom of each tube slot to allow for fluidic connections to jut outward. In previous iterations or improvised tube holders, the existence of fluidic connections at the bottom of the tubes could obstruct full insertion and make it difficult to secure the tubes in place. The outward angle of the slots helps prevent tangling of microfluidic tubing. The height of each slot was increased to prevent tubes from being knocked loose during device set-up/handling. The wide surface area of the base also helps prevent the tube holder from accidentally being flipped during a given experiment.

3D Printing Recommendations

For 3D printing, it is recommended that users select a smaller layer height (i.e. 0.08 mm), use smaller nozzles, and enable printing head retraction to make the surface of the printed device smoother if possible. This makes it easier to clean the tube holder with ethanol. To make the surface even smoother, consider acetone vapor smoothing.

Downloadable Files

I used eSun PLA and a Creality Ender 3 S1 Pro to print this part. The STL file, Cura Profile, and Solidworks Part file for this tube holder are available for download here: Box Link

Figure 1: Peristaltic Pump Circulating Flow Tube Holder. A) Photograph of Circulating Flow Tube Holder. B) Solidworks Drawing of Circulating Flow Tube Holder with Dimensions. C) 3D Solidworks render of Circulating Flow Tube Holder.