Tuesday, November 11, 2014

Cosmetic Issue - Bits & Pieces of Filament on the Print Table

I noticed that when I printed two objects of different colors, little bits and pieces of filament would end up on the print table.  This puzzled me because I knew that the Cube 3 had two wipers that should have taken care of that problem.  So, I decided to investigate and send the Cubify engineers my observations.

As some of you know, I often use the tools I learned as a science teacher in my analytical efforts.  But, I also have a video production background that also comes in handy from time-to-time.  And, that is what I turned to in this case.

I first shot a sequence of video that captured what was happening.  My camera is not capable of true 200 frames per second high speed capture,   But, it is capable of shooting at high shutter speeds resulting in sharp images of moving objects.  So, I used video editor to slow the action down as much as it could.  This resulted in this video sequence.

As you can see, the action happens very quickly in real time.  So, even slowing it down a little bit was helpful in determining the sequence of events.  Even so, it still wasn't completely clear how those bits and pieces where forming.  So, using Camtasia to capture my screen as I operated the shuttle in my video editing application I was able to analyze the video, and document what was taking place, on a frame-by-frame basis in this next video.

The Cubify Team is aware of the issue and working on correcting it.

I expect it will be addressed in a future firmware update.

Observation Conclusion:
  • The issue is cosmetic only.
  • It involves the resting placement of the print jet and possibly the extruder control (Prevent dripping)
  • It affects both left and right print jets
  • Most commonly seen in SOME two color prints (same layer color changes)
  • It should be able to be addresses entirely in firmware
  • Should hardware changes be required, it will only be to user replaceable parts such as wipers or wiper try assembly
I consider this a very minor issue that will not be permanent to the Cube3 user experience as it appears to be something that can and will be addressed through firmware updates.  While it's ugly, it is definitely NOT a "show-stopper" in terms of making a purchase decision.  While it does affect the first layer of all pieces, it's not a big issue unless the design of the object requires same layer color changes. 

This is the kind of thing I expect to see in an entirely new product.  And, is typical of the issues discovered so far with the 3rd Generation Cube 3D printer in that they do not demonstrate any flaws, serious or otherwise, in the hardware design of the basic printer itself. 


  1. Tom,

    I do agree there is an issue from the time the wiper wipes to the time the printer begins printing that causes a crude first layer. I think the best fix would be to use a small section of the build plate to make an excess pile then begin printing. Thats kind of what other fdm printers do.

    As for your wiper, it looks much to high. It should not be bent over being squished by the housing of the jet. Mine is short enough that only the jet nozzle itself touches the wiper and only when the nozzle passes by does it make contact.

    May I suggest since the wipers are disposable just cut down your wiper slightly....maybe that will help.

    1. Interestingly, I'd already done that (crudely) and was waiting for some extra wipers to experiment to find the absolutely optimal height. But, the fact that in your machine the wiper height is already different, might mean that the height issue has already been addressed in printers delivered after mine.

      The method that you suggest, was the one that I used with the Cube2. I just created a small one <.5mm object and made it the first object added to the Cube Client.

      I like the way you think! :)

    2. It turns out that not only the height of the wipers might be different for machines built at different times; but, the bins that hold the wipers might show some differences from one side to the other. It's interesting to know; but, not a big issue since we can cut them down, as you suggest, so that they hit only the Print Jet and not the Print Jet housing. I'll let you know when I get the extra wipers with which to experiement; but, even my crudely cut wipers work better than before.

  2. Tom,

    I'm sure everyone so far has noticed that manually setting the gap is difficult to do one the cartridge has been used already as the nozzle has a slight bit of filament sticking out which is too small to cut or snap off. While the optical auto gap and level is nice it has difficulty with reflectivity and sanding is needed even after a single print for me as otherwise it fails.

    In my opinion I think 3dsystems should utilize there quick release print jet nozzles and simply have a pressure sensitive manual sensor that can be snapped into where the cartridge nozzle goes, let it do its thing to level and gap, then untwist and pop in the new cartridge. If you need to reset the gap mid cartridge the same step would be applied. Something like a test light would even work so you raise the bed manually on press at a time until the light turns on and presto. I think they overlooked the simplicity and also the beauty of the disposable print head and how that empty void where the nozzle goes could eliminate an expensive and tempermental optical sensor with a tried and true manual sensor.

    Anyone want to back me up? :-)

  3. Taking advantage of the plug & rotate jet lock for a manual gap gauge is a VERY interesting solution. I have no idea as to the comparative pros and cons; but, it sounds logical to me. :)

    In my machine, the print jets are a tiny bit uneven. But, I haven't had any failures since I calibrated using the 1.08B firmware additions. Again, I am using an early build machine and I believe that the head assembly is now slightly different than mine and auto gap should be easier.

    These are the kinds of issues they can improve over a very short period of time. The engineers at 3D Systems really hop on these things quickly.

    I do wish the up/down increments were more fine. I have fat fingers. :)