Frustrating Filament ...

So, for a while, I've been having issues where everything is printing great! but then suddenly I'll start under-extruding and eventually stop extruding all together.

It's been very very frustrating to say the least. :/

Every time I've cut the filament, I've measured the end that's going into the hot-end. Each time I've read a diameter of > 1.90. This time around, however, I remembered that I have an extra E3D. So I broke it out and took some measurements.

You can see that the opening of the E3D as it enters into the active cooling block is 1.91.



and if I thread the bad filament into the block, it stops cold at where the filament grows too large. I took a couple of readings of the filament at this point.




elsewhere, before the block point, you'll see the diameter is good. I took a reading at one point



Now you don't see it in this cutting as you would in others but many times it looks as if the center part of the filament was pulled out and it formed a tube toward the hot-end.

Unfortunately this happens with nearly all of my filament. And they're from different makers and distributors. Very very very frustrating when you go for a few hours, you cross your fingers and then later, you start under-extruding and stopping. Which of course ruins the print.

Whenever I find a roll that prints well, I do NOT want to change it out. For all I know the next one will screw up.

Unfortunately, as I type this, it's screwed up again Didn't even make it past the first layer. *sigh*

I thought this *might* be an extruder issue, so I swapped out hobbed bolts. This happens with the new one too. The filament is just too wide to get past the initial narrowing.

 

Wow that's really bad luck, never heard of filament with more than 1,85 mm real Diameter (usually it's 1,75 +- 0,05)
But 2mm, that's really bad filament...
where did you get it?

 

Is this filament from the Robo 3d site?

 

Try drying it and remeasure.

 

According to the E3D drawing the inside diameter "should" be 2.0mm

 

Melody, I have been having the identical problem and feeling incredibly incompetent because I can't even get a first layer down right now. Two days ago, printed one thing great. ALL DAY yesterday - zilch. Today, no joy either. Just frustration. No, I haven't measured the filament or e3d though I have tried different nozzles with no real success. I swapped out all my pololu boards, calibrated over and over, tried wildly different temps, flow rates, extrusion multipliers, Slic3r settings, Cura settings... my filament is stored in a low humidity container (30%) in a low humidity basement and I have also tried multiple filament batches, types and manufacturers. I keep thinking that it can't be a big thing, but nothing I do seems to solve it. The flow is OK when I push it through or turn the gear by hand but when I go to do a part, it becomes erratic and leaves little blobs within a diminished stream of plastic that never works. This has been going on for a while, obviously. I have rebuilt the e3d, replaced thermistors, both boards, wiring.... I'm even contemplating, gasp, trying the stock hot end. Perhaps I'll drill that 2mm into my e3d first, though. And stop dancing around the house singing "someday my prints will come" with a crazy cant to my eye. Promise.

 

What happens to a noodle when it gets wet?

What happens to it when you dry it out?

 

So the filament I'm using is from different manufacturers. I have Robo 3D's filament here as well as filament from Zen Toolworks, Colorfabb, etc. They all exhibit this behavior.

Mike, the measurement of the ID of the hole is based upon me measuring, BUT my angle of measure may be off. I just know what the exhibited behavior is. :/

I'm not in a completely dry environment but it's not very wet either. In fact the SF Bay Area is having a drought at the moment. One of the dryest in the history of the area. We're all hoping for rain.

I've got some filament I haven't opened yet including some that are supposedly "pro" level (i.e. very accurate). Hopefully those will extrude right :/

 

Yeah I know that actual vs ideal can vary quite a bit. They list their tolerance as ±0.05mm so at worst it should be 1.95.

Worse comes to worst you could bore it out with a close fractional bit

 

Just sick one in oven for a few hours and remeasure. If nothing else its an easy experiment....much easier than drilling extruders...

 

And yes, I opened a brand new sealed and dehydrated batch of PLA - one print. Racegraphix: drying is not a big deal, you're right, but I have little faith that is the problem. I shall measure for a while before anything else. BTW, drilling the e3d isn't a problem. Not compared to the hassles!

 

From watching the news lately, it's not humidity, it's called ice!

 

I've just been measuring filament. The worst (and cheapest) was 1.86 and the best was 1.75-1.76 (Colorfabb XT). I live in Maine. Florida is not icy. Even when it is, it isn't.

 

Most vernier calipers are not accurate at small inside measurements as the thickness of the gauge gives a false reading. If you measured 1.92 it would more likely be closer to 2.0

 

Well, I just finished a tear down of the e3d. What I found was the answer, at least to my problems. There were two places where the filament was binding. One was at the very base of the heat sink where the filament meets the stainless guide into the heating block. It was minor, but appreciable. I drilled it out to 1.935, or so, and couldn't tell if it was filament or a burr left from the original drilling, but filament fit tightly, yet moved through after that. At the bottom of the stainless connector, there was a fair amount of filament, either XT or t-glase - the bits that came out were enough to show they were clear and not colored. This was a bigger blockage that stopped cold filament movement completely. It must have heated enough to allow some flow when in use, but not enough for decent printing. I drilled that out to the same diameter as the other, reassembled and tested. It works. Normal temps and plenty of flow. I am going to get a 2mm drill bit today and, if it starts happening again, take it out all the way. I'm also going to assemble the whole hot end with greater force than I previously used. Though I did it according to the instructions, I might have gone a bit easy on it for fear of breaking it. This may have led to filament leakage at the two joints discussed. While it may not be the whole story, it is enough to get me printing again and hopefully others who are experiencing the same symptoms. I hope this whole thread dies. Shrivels away to nothing.. ever again...for anyone.

 

The thread remains alive. Damn. Two prints (small ones), good feed, halfway through the third... crap. I'm headed for the 2mm solution. Will post results if it works. Not sure what I'll do if it doesn't. Not sure at all...

 

So, I think I am closer to the problem and solution. When I tried to print some wood PLA a while ago, I got repeated clogs and finally gave up on it. Those may or may not have been the reason for the diminished size of the e3d feed tube, but the fact of the obstructions is correct either way. In combination with irregular filament diameter, the feed would be diminished enough to destroy the prints. Worse, I measured and drilled a cold system, with the coefficient of expansion when hot, it exacerbated the problem. When I added more heat to try for an increased flow, more worse. I just managed a real print that isn't perfect but in comparison to what I was getting before? Fabulous.
My personal solutions: High quality, well dried filament. 2mm e3d filament feed. Periodic diameter maintenance. Random pleading. Let's hope this lasts.

 

Thread-end, for me at least. I went to the hardware store today and bought 2 springs exactly the same length as the extruder springs, but one gauge thicker. Replaced the two that came with ROBO and printed a totally perfect test of a complicated print and normal temps. For any of you experiencing filament problems, this might be a good, inexpensive and effective place to start looking at the problem. I cannot express just how glad I am to have discovered this.