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Extrusion Issues: Cleaning and Lubricating Filament

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I have two Ultimaker 2+ (upgraded from 2's) that I have been running for 18 months.  Prior to these printers I had built a Prusa I3 and had a Makerbot Clone.  

My number 1 recurring issue on my Ultimakers always seems to come back to extrusion.  I do a lot of atomic cleans, I regularly replace the teflon coupler, I keep the extruder gear clean, and with the advent of removable nozzles, I change nozzles a lot.

What I have not done until recently is lubricate the bowden tube.  I did replace them with more slippery versions prior to the "+" upgrade which of course did come with new tubes.

The "+" upgrade certainly improved extrusion.  Startups are much more reliable without my attention (prior to the upgrade I often manually primed the nozzle just to be sure of a good startup).  

Recently, however, my "+"'s have started to sputter a little on the extrusion front.  Having done all of the normal things that I have been doing I looked for something new that I have not tried and came across a suggestion to lubricate the bowden tube.  This suggestion was made on the 3D Hubs forum and since I had not seen it on the Ultimaker Forum I did a couple of searches and did find some references suggesting the use of dust filters that also lubricate.  The feedback was very mixed with recommendations that you not lubricate stuff going into the feeder.

I had used a filament cleaner on my Makerbot Clone and it did not seem to hurt so I decided to go ahead and try it on my Ultimakers.  The results have been profound (in a good way).  The only difference between the failed print, due to under extrusion, on the left and the near perfect print on the right was the addition of a filament filter that also lubricates:

IMG_5210.jpg

The questions this leaves me with are:  

First, is there a reason that I should NOT be doing this (as in will I see some long term harm)?

Second, what lubricant should I be using (right now I am using a high smoke-point temperature nut oil)?

As I mentioned, I am now doing this on both of my printers and am really happy with the result though I have had to adjust my profiles to lower my extrusion adjustments as compensation for stuff getting to the nozzle more easily!

I do question myself as to why I have not done this before and wonder if my extrusion issues have been threshold related.   Meaning that I start to see issues at a certain threshold of resistance.   Say that "R" is resistance and R=100 is the point where problems start to occur.   Say that changing a nozzle gives you a benefit of -10, an atomic clean might add a little to that as it may also clean the boundary between the nozzle and the teflon coupler so maybe a -15 with a nozzle change.   Changing the teflon coupler gives you another boost, maybe a -30, depending on how bad it was.  In the meantime, however, the bowden tube has been adding resistance.   Say a +5 every month.   Once you hit the 100 you can improve things with nozzle changes, atomic cleans, and new teflon couplers, but the inexorable creep of resistance building inside the bowden tube will ultimately take you to the threshold and beyond.  Enter lubrication?

So...am I making any sense?   Why is lubricating the bowden tube not a more popular suggestion?  Thanks for listening!

Edited by Guest

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I my mind it just feels so wrong to add a oil into the extrusion system, i am no polymer chemist, but that added oil has to go somewhere, and extra oil in the plastic will probably make for less layer adhesion etc...

 

That is why I am asking! It does seem like it could be problematic but the prints that I have done to this point, and there have been quite a few, show no issues as of yet. I have a layer adhesion test that I will try to do today or tomorrow but based on my observations to date I don't expect to see a difference from when I did it some months ago.

Hopefully someone that is a polymer chemist will chime in!

Will

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I have added oil when printing ninjaflex and it doesn't seem to affect the print quality. It certainly looks great but is it weaker? I don't know. I don't think it hurts anything. I think the oil stays apart (ends up mostly on the outside of the print) from the print. But I don't know. I have a stress/strain analyzer machine. So one of the things I will test is prints with and without oil to see if this affects flexibility or strength of the printed part. Some day.

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I have added oil when printing ninjaflex and it doesn't seem to affect the print quality.  It certainly looks great but is it weaker?  I don't know.  I don't think it hurts anything.  I think the oil stays apart (ends up mostly on the outside of the print) from the print.  But I don't know.  I have a stress/strain analyzer machine.  So one of the things I will test is prints with and without oil to see if this affects flexibility or strength of the printed part.  Some day.

 

Thanks gr5, I was going to tag you for an opinion but you beat me to it. I will do my rudimentary stress test today. The amount of residual oil ending up coming through the nozzle has be pretty tiny so I would be surprised if there was a difference. Of course both of my printers are now filtered so my baseline will have to be the data from a heat related test that I did some months ago. Not the best scientific method!

I am just amazed at the difference that it has made,

Will

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I did a rudimentary strength test with results that while contestable in terms of them being "apples to apples" would still indicate that strength is not an issue.   The test was not apples to apples for two reasons, first that I can only base my before strengths on data collected months ago, and second because the test prints I used back then look like they might have suffered from a wee bit of under extrusion themselves!  So, when I printed two new test pieces and put them to the test one destructed at 17.59kg and the other lifted my desk off the floor so I gave up.  In my original test the break point average was 14.3kg.  Whether apples to apples or not I am satisfied that strength is not an issue!

BTW, here is a link to the dust filter that I am using. Obviously there can only be a little oil entering the system.

Edited by Guest

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Interesting that I had recently seen Barnacules Nerdgasm had a video episode on this.

 

I find the guy hugely obnoxious but he is right about the difference this can make.  Not sure why he felt the need to cobble a filter together when there are dozens to choose from that can be printed!

In any case, he is focused on the dust aspect until the end where he mentions the benefit of lubrication.  It might be a combination of both but I think the lubrication is the bigger benefit.

Edited by Guest

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Interesting that I had recently seen Barnacules Nerdgasm had a video episode on this.

I had also stumbled upon this guy and this video, I don't remember how.

His filter concept may need a bit of refining, but I like the simplicity of the basic idea. And for sure silicone oil does not get ransic like vegetable oil, which might become a tough mess over time. And it doesn't seem to make the filament slip in the feeder either (which is a bit surprising to me).

Off-topic: also have a look at his gaming computer in the background: with four huge screens and 24 CPU-cores, I guess it will make any flight sim, or a GTA V race game, a whole new experience. Slightly above an average setup... :)

And if you use Windows 10, also have a look at his videos concerning the creepy privacy issues; it is very well explained.

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Interesting that I had recently seen Barnacules Nerdgasm had a video episode on this.

I had also stumbled upon this guy and this video, I don't remember how.

His filter concept may need a bit of refining, but I like the simplicity of the basic idea. And for sure silicone oil does not get ransic like vegetable oil, which might become a tough mess over time. And it doesn't seem to make the filament slip in the feeder either (which is a bit surprising to me).

And if you use Windows 10, also have a look at his videos concerning the creepy privacy issues; it is very well explained.

 

IMG_5268.jpg Here is a picture of the dust filter / lubricator that I am using. Pretty simple, quick print, that looks nice hanging on the back of my expensive printers!

Maybe it is because I am a yank living in the UK but I am sensitive to the stereotypes that occur to people when the think about an American...and Barnacules Nerdgasm hits the majors: Too loud, too large, and too over the top! Regardless of the quality of his content it pains me to watch his delivery!

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Ha! You should meet him in real life! He is the same. But I love all people and he is easy to love. You have to look for the good in everyone. He is a very nice and honest person. Warm, friendly, loving. He knows he is lucky to have a wife that puts up with him. He always shows a happy face even when (almost always) he is in physical pain. I'd rather hang out with him than someone who is depressed.

But I know exactly what you guys mean. Over the top. Crass. Jokes not funny. But that covers up a genuinely kind person. He's quite smart also and somehow finds patience when alone.

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The amount of work he puts into those videos is impressive (I love the snarky side comments he makes) I recall he was laid off from Microsoft a year ago and has done a good job with the content of his channel. I've never met the guy but imagine he's hilarious to be around.

I didn't mean my comment as a dig on him....I like his content...just not one I could watch every day :) I follow Thomas Sanladerer's channel too. With his engineering background I really like how he breaks down the technology for the viewer

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But I know exactly what you guys mean.  Over the top.  Crass.  Jokes not funny.  But that covers up a genuinely kind person.  He's quite smart also and somehow finds patience when alone.

 

Funny that you should know him in person. As with all things that you post I will bow to your knowledge on the topic of him being a top tomato. :-o As a casual bystander I wonder if he would have more viewers if he kept up the great work on content but maybe rebranded himself a little...? But you do have to be true to yourself and maybe his followers that he has today would bail on a more boring version of himself? BTW, I can very personally appreciate the comment on playing through pain.

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Just doing some experiments on the lubrication issue. Using rapeseed oil certainly reduced friction in the bowden tube, whether it will improve prints - time will tell.

I am going to try glycerine as the lubricant. I'm a bit worried that over time, oil will get onto the build plate and reduce the sticking effect of the PVA glue. Glycerine is water soluble, so should wash off easily.

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Didn't see any obvious change to a print after lubrication, maybe my |Robert| feeder is doing its stuff.

 

My environment is pretty dusty which may have contributed to friction in the bowden tube but the impact for me was profound (as you can see from the picture at the start of the thread). If you can feel a smoother feed then I would suggest that somewhere down the road you will avoid some under extrusion!

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