Saturday, January 24, 2015

Fix for Filament Getting Onto Air Vents Beside Wiper Tray

I received an e-mail from Ibrahime Abraham recently and it sent me off on another quest.
"One re-occurring issue I have been having with the printer though is bad wiping of filament into the waste bin. ...  Once print jobs are completed I notice that filament that has been wiped is sent behind the waste bin and actually enters the inside of the printer housing..."
Early Cube owners observed that bits and pieces were dropping onto their print tables.  There were two issues causing that.  Some of the wiper trays were designed so that the wipers were too high, dragging the underside of the print housing.  In newer Cube 3's that has been fixed.  The wipers are just the right height to barely brush against the print housing.  The fix for this, if your printer has the taller wipers is to simply trim them a bit with an Exacto knife.  Just be careful you don't trim too much.

The other issue, early on, was the path of the head just prior to beginning to print.  That issue was fixed by early firmware and Cubify Software updates.  If you have faithfully updated both the Cubify Software and the firmware this should no longer be a big issue.

But, one issue still remains.  And, that is the issue that Ibrahime wrote about.  Sometimes, filament fails to drop into the wiper bin and, instead, falls onto the vents behind the wiper bin.  The risk, of course, is that filament will fall through the vents and into the machine... over time having some adverse affect.

Having a 3D printer, my first thought was to try to design and print a fix.  But, that was applying the wrong hammer to the problem.

Sometimes the old bailing wire and duct tape approach beats the high tech approach.  And, in this case, that exactly how I tackled the problem.

Goal:  Keep filament from falling on the vents behind the wiper tray

The goal was simple enough.  I needed to come up with a barrier that would prevent filament from ending up on the vents.  It had to be flexible enough not to impede the print head housing; but, tall enough to touch the housing.  After several failed 3D printed designs (not flexible enough) the solution came from observing the wipers... which met the criteria of flexibility.  I quickly abandoned the 3D printed approach for the bailing wire and duct tape approach that has served us all so well over out lifetimes.  It was time to apply "Tom's Rule"
Tom's Rule:  When all else fails... get out the glue gun.
Admittedly, applying Tom's Rule on a high tech 3D printer can be a bit scary.  But, being braver than I am smart, I forged ahead anyway.

Solution:  Wide Rubber Band, 1 pair of Scissors & a Glue Gun

The solution came in the form of 1 wide (1/4") rubber band, a pair of barber's scissors and an old and trusted glue gun.

Given the fact that rubber bands have a bad history of deteriorating rapidly, It's quite possible that I will regret my choice of working materials.  But, the rubber band was, in fact, flexible.  It was wide enough to be used.  And, best of all it was right in front of me.  That has to count for SOMETHING.

The scissors were right here, too.  Only the glue gun had to be found by rummaging through draws.  But, once found, the task took off with few hitches.  The idea was to hot glue a section of rubber band to the back of the wiper tray housing so that the rubber band formed a barrier between the wiper housing and the vents.  Here is the result.

Rubber Band Barrier
As you can see, I wrapped the rubber band around the back of the wiper housing as well as along the back side as I had observed that some filament seemed to escape out the back at times.  The rubber is attached so that one edge will make contact with the print head housing.  It is flexible enough not to be a problem at all.  

Here is what it looks like when installed.

Rubber Band Barrier in Use

Will it Work?

Who knows.  It appears to be working right now.  But, not enough time has passed to call it a resounding success.  And, the question is still open about the longevity of the rubber band, itself.  I don't THINK it will be a harmful modification; but, even that isn't proven thus far.

I'm guessing that it may void the warranty... which is why I pointed out that I'm more brave than smart.  But, if it does all that I hope it does, it should lengthen the lifetime of the printer by keeping the filament from dropping down into the innards of the machine.  (Note:  Those of us from the south are particularly fond of using the word 'innards' whenever we can.)

I put this out there for what it is... my solution to an issue that may or may not be all that useful.  Hot gluing things to their products is rarely something that manufacturers like to embrace.  Hopefully, at some point, the designers will revisit the wiper and vent issues.  But, it is well down on the list of priorities right now.

I'll post updates on the effectiveness after I've had time to actually assess it.  In the meantime, I just want to thank Ibrahime for setting me off on the chase for a solution!    



  1. I have also experienced this filament issue. If you find this solution works, I'll try it out!

    I've had my cube 3 for 2 weeks. Customer support at 3d systems has been great! I had a clogged cartridge and a cartridge that the printer wouldn't recognize. They are sending me a replacement for the one that isn't recognized and sent me instructions on how to unclog the other one. The unclog procedure works like a charm!!!!

    A couple of things I have discovered:

    As you have stressed in your blog, "Do not try to print until you have calibrated your printer!" I always recalibrate after changing out cartridges.

    Also I have found that if I let the glue completely dry to the touch, I never have a problem with the model coming unstuck during the print. I'm thinking about using my wife's blow drier to speed up the process. Or... I should probably buy my own.:-)

    Question.... When printing multi color prints, does the printer always have to stop between colors to heat the print jets? Or am I doing something wrong?

    1. No. That is the way both the Cube 3 and the CubePro work. I'm assuming that they cannot keep the idle color print jet at full temperature because (1) it would drip and (2) it might toast the filament not being extruded.

      By moving over to the wiper tray they are heating the newly selected tip and COOLING the previously selected tip.

      That means color prints take a LOT longer for the same volume than monochrome prints.

    2. While the rubber band and hot glue is ugly. It does work. I put in HOURS trying to design a 3D printed solution; but, the tolerances are SO close in that area that nothing so far has been as successful and safe to the printer as the rubber band solution. Sometimes ugly just plain works. :)

      But, I will try to find a more permanent replacement for the rubber band itself. I'm thinking that gasket material might be the better answer.

      Fortunately, the hot glue is relatively easy to clean off the wiper tray.

  2. I've had the same problem, and my solution is to use some "window" material from packaging that is thick enough to hold the shape but thin enough to fit there - such as you find in a lot of computer accessory packaging. It is generally the same plastic as soda bottles, so it is pretty rugged (and clear!).

  3. That's a great idea. The material is flexible enough not to impede the print jet housing. Nice!

  4. Do any of you guys know where to purchase the wiper clips themselves?

  5. Does anyone know where to purchase new wiper clips themselves without buying the entire bin?

    1. Sorry I didn't get back to you right away. I was teaching all week.

      Try calling the support line. I'm guessing they just might send you some since there is no way to order it that I know about.