Sunlu S2 Feed Redirect Bearing Roller Guide

Preface/Supplies

This model, just like the one from _bdjester, utilizes a 608 skateboard bearing that must be (somewhat forcefully) pressed into the spool. I used double-sided mounting tape just like they did; however, I got away with using the 15-pound indoor version from Scotch as well (link to Amazon). It's also recommended to have a length of at least 5cm PTFE bowden tubing, an explanation as to why this is included can be found below. This is the 1-meter section I bought from Creality.

Description

This filament guide roller was primarily modeled in an effort to make the iteration by _bdjester easier to print for everyone. The goal was to create the smoothest exit possible from the Sunlu S2 filament dryer in a downward direction. I tend to dry my filament while the printer is running, and I lack the space to keep the dryer on my desk alongside the printer, so I resorted to mounting the dryer to the gantry of my Sovol SV01 Pro (more on this later).

After mounting it above, I needed a fix for the lack of a bottom exit from the dryer. There are models out there that allow for a downward exit, but all that I could find required the lid to be partially open, and I never liked that solution. This fixes that issue without any drilling or other permanent modifications to the dryer.

I designed this guide explicitly to be used in conjunction with this brilliant model by killdaclick. The exit angle provided by their filament guide leads seamlessly into the roller for a smooth transition downward. It may not be required, but I highly recommend doing the simple print; and doing so in the most temperature-resistant material you can (PETG has worked fine for me).

Additionally, I remixed a base that attaches to the 10×10 extrusion on top of my printer, positioning the dryer so that the filament run sits precisely in the center of the build volume. On top of that, I created a filament guide to attach to the same 10×10 extrusion so the filament run from the top of the dryer to the print head will have minimal force applied along the axis that could cause the dryer to tip over. Links for these models will be included as soon as they are published.

All of this combined led to a system that works extremely well (in my biased opinion), with little to no extra load on the direct-drive print head.

Printing

I printed this in PETG, but I don't see a reason that you couldn't also print in PLA.

As stated above, I designed this model to be as simple to print as possible. Print in the orientation shown in the group photo and as provided in the 'All Parts' file (flat portion of base down, spindle on its side, pin on the long flat area). All overhangs are set at an angle ≥45°, all tight turns are filleted, and no model has a small footprint for contact with the build plate. I'd love to hear if anyone has any issues.

Pre-installation

Grab some masking tape to help with temporary positioning of the guide. Also, have your mounting medium of choice on hand.

The 608 bearing can simply be pressed into the spindle. If your tolerances are right, it should take some effort. I recommend starting by finding a sturdy flat surface around waist height. Put the spindle down first, then set the bearing in place. Position a large, flat, sturdy object on top of everything. Slowly use your body weight to press the bearing into place.

The section of PTFE tubing that I used was trimmed to a length of ~40 mm. This is recommended by the designer and works to smooth out the bends of travel, reduce friction, and help their filament guide stay in place within the dryer. It may work fine without the Bowden section, but I can't guarantee anything in that case.

Extra tip

Be sure that when cutting to length, you do your best not to smash the ends closed, as this will increase friction against the filament substantially. Try to cut a little, rotate the tubing, and cut more, continuing to rotate as you cut. If it smashes flat, you can insert a pencil, scribe, center punch, or any other conical-shaped object to open the end back up.

Installation

Start with the spindle in place on the base and push the pin in just enough to keep the spindle in place. It doesn't need to be pushed all the way through yet.

• When installing, I've found it's best to start with the filament guide by killdaclick. Slide it in from the inside of the dryer, then insert the section of PTFE tubing, allowing it to stick out slightly past the exterior face of the dryer.

• Insert a portion of filament through the guide so it sticks out past the PTFE tubing.

• Tear off two lengths of masking tape so they're ready to grab with one hand.

• Do a dry alignment (without any mounting medium) of the roller base to get it into a position that best aligns with the exit angle provided by the model from killdaclick.

  • If using mounting tape, go ahead and stick one side to the roller base while keeping the film on the side that will stick to the dryer itself (see below for placement). 

• Using one hand to hold the base, use your other to extend the filament out from the dryer over the spindle to check alignment and ensure a smooth transition.

• Center the base horizontally by pivoting around the exit hole and using the ridges in the lid to index the widest points of the base (they should land on a high ridge).

• Once in position, grab one length of masking tape and run it over the top of the guide's base just above the exit hole. The other will go under the base on the face that was in contact with the print bed during printing. This should hold the base to the face of the dryer's lid.

• Verify that everything is as you want it before removing the pin and spindle, removing the filament, and (potentially) pushing the PTFE tubing back to nearly flush with the face of the dryer's lid if you suspect it could get in the way during final attachment.

• Remove the top portion of masking tape so the whole base can hinge downward on the bottom section of tape.

• Remove the film from the second side of the mounting tape. Apply glue to the contact face of the base if that's what you're using. 

• Carefully hinge the base back up into position for final attachment.

• Follow the recommended wait period for the adhesive you used before putting the dryer into service.

That's everything!

If you have any suggestions for changes, leave them in the comments and I'll do my best to find time to implement them. Or, if you'd like to make changes yourself, continue on to the next paragraph.

Lastly, this model was designed in Onshape, a web-based 3D modeling software. Because of this, I've made the file available for everyone here. You can simply copy the file to your profile for any edits you'd like to make. However, I'm no expert in 3D modeling, so the file may be a bit messy and unprofessional. If you'd like help figuring it out, I'd be happy to offer pointers. Additionally, the file may change slightly over time. If I do make changes, I'll be sure to add new versions so anyone can roll back to iterations they prefer. I've also left a few notes in the document that can be found in the left column ribbon. You can also use the link to export the files in any format you prefer.

Ignore the pin the the photos, I originally designed it to be printed in two halves and did a redesign for the final model.