STEM Wind Tunnel Flush Interior Windows Modification

This is a 3D printed frame into which you can glue/silicone sealant mount a laser cut acrylic window. This allows the windows to sit flush to the interior wall of the test section. This significantly improves flow quality. A 1/16 inch or 1.6 mm O-ring groove is included to improve the face seal of the test section. Cut a custom o-ring to size using 1/16 inch o-ring cord stock (e.g. https://www.theoringstore.com/store/index.php?main_page=product_info&cPath=117_119&products_id=24727).

Instructions:

1. Print four frames from the 3mf and four laser cut the windows using the svg. I recommend keeping the protective film on the acrylic during cutting and gluing processes. I recommend a somewhat flexible/tough filament such as PETG or PCTG.

2. Run a bead of silicone sealant or your adhesive of choice around the inner groove of the window frame. I used Permatex Blue Gasket Maker (https://a.co/d/0dy4zHJP) but any rubbery and moderately sticky adhesive you have on hand will do.

3. Place the inside (smaller) edge of the frame down on a flat, easy release sheet. I recommend parchment paper or aluminum foil. Insert the window such that it sits flush to the inside edge.

4. Wipe up any extra adhesive and allow it to cure. Remove the protective film on the windows after adhesive if fully cured.

Files Included Included:

• .3mf File ready for your slicer

• Solidworks files if you want to make edits

• Inkscape .svg for laser cutting 1/8 inch or 3mm thick acrylic windows.