Under-workbench filament guide

I have a relatively small workspace for my two printers. To reduce workbench clutter and make my workspace more usable, I routed the filament from the spool holder, through the tubing guide to beneath the table top. From there it goes to a second tubing guide, where it goes back through the table top to the printer filament input. I use Creality's Multi-kilo Feeding Holder to hold the spools (up to three 1Kg rolls can be loaded or one 5Kg roll). (https://store.creality.com/products/3d-printer-multi-kilo-feeding-holder-black).

Beneath the table, I route the filament through PTFE tubing to avoid entanglements where it would be difficult to access them. I tried Creality's Bowden Tube, but there was too much friction for traveling 1 meter through the tubing. I bought PTFE tubing from Amazon with a slightly larger internal diameter and it worked great (https://www.amazon.com/UNIDO-Teflon-Creality-Extruder-Printer/dp/B0DP22LT24/).

There is one dimension you MAY have to modify, the table thickness. Sometimes, friction between the feed tube and the filament would try to pull the tubing guide out of its hole in the table. I added a tubing snap clip to hold the tubing guide in place. The groove that accommodates the snap clip has to be located a little more than YOUR table's thickness away from the tubing guide's flange, so that it is located correctly for your table instead of mine. The CAD model is in Onshape CAD and you can access a copy here: (https://cad.onshape.com/documents/6b61d41021cfaeee96a57192/w/2b24692c27f3bdb6b6074602/e/1ac46c7a61daf9ce3e7dbbb8).

Onshape is free to use. Once you have an Onshape account, copy the file to your workspace and open it.

1. In the left "Features" column, find "Sketch 1" and double-click it to edit it. A dialog box will open.
2. Double-click on the "Table thickness dimension (see image) of "30" in the graphics area and change it to about 1 mm larger than the table thickness. Enter your table's thickness (plus clearance)
3. Click the green check mark in the "Sketch 1" dialog box to incorporate the change. The model will regenerate.
4. Once the change has been made, export a new STL by right clicking on the "Part Studio 1" tab in the bottom-left corner of Onshape and select "Export." It defaults to an STL export, so just select a folder on your computer to store the STL file.

The hole size you need to drill in your table is 13mm. To get the best quality top surface for the guide, orient it for printing as shown in the images. The tubing length should be long enough to reach its destination and NOT turn sharp corners (where it could cause friction and bind). The PTFE tubing should be limited in length because the longer it is, the more friction it'll generate with the filament. I use about 1 meter of tubing per guide set and have experienced zero issues.

To install the guide:

1. drill a 13mm hole BUT TEST MULTIPLE LOCATIONS FOR YOUR SPOOL HOLDER BEFORE DRILLING!!! Make sure the spool holder and spool do to interfere with your printer's table travel.
2. insert one end of the PTFE tubing through the hole in the bottom of the guide and feed it in as far as you can or at least until it starts protruding through the top flange. It's a snug fit.
3. insert the opposite end of the PTFE tubing into the drilled hole in your table (from the top side) and feed it through. When you reach the tubing guide, press the tubing guide into the table top.
4. slide a tubing guide clip into the ring groove of the tubing guide, beneath the table top, to secure the tubing guide to the table.
5. drill another 13mm hole, where you want the filament to come up through the table and into the printer. This should be as close to the printer's filament input as possible so as to not clutter your work area or snag on other items on the table. BUT TEST MULTIPLE LOCATIONS FOR THIS TUBING GUIDE'S HOLE BEFORE DRILLING!!! Make sure the tubing guide and tube do not interfere with your printer's table travel or catch on any cables or tubing.
6. feed the free end of the PTFE tubing through the 2nd 13mm hole, from beneath the table top to above it.
7. insert the free end of the PTFE tubing through the hole in the bottom of the 2nd tubing guide and feed it in as far as you can or at least until it starts protruding through the top flange. When you reach the tubing guide, press the tubing guide into the table top.
8. slide a tubing guide clip into the ring groove of the second tubing guide, beneath the table top, to secure that tubing guide to the table.

Now, you're ready to print. Just mount a spool, guide the filament into the PTFE tube that protrudes from the top of the first tubing guide and feed it in manually until it protrudes through the second tubing guide. Pull the filament from where it is protruding and insert it into your printer as you normally would.