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mhackney wrote:

dpmacri wrote:

mhackney wrote:Have you ever tried to move a stepper that is powered up? You have to overcome the holding force which is quite high on these little buggers. The "retract" that I observe is a lot more than the spring effect of compressed PLA could provide. It's an odd thing!

Yeah, they're tough little buggers . But perhaps the skipping is due to an overheated mosfet and so the motor loses all of it's holding power momentarily while the mosfet shuts itself down for a split second .

Well, I've been running 100% reliably now and feel confident (after some confirming tests) that I know the root cause of my and probably other's EZStruders skipping steps. The culprit? heat! My attempt to install a heatsink on the extruder driver was almost a disaster but luckily I did not do damage to my RAMBo. But, I did remove it. I then installed a 40mm fan in the cutout LCD opening in the door in the chamber when're the RAMBo resides:

[img]http://mhackney.zenfolio.com/img/s10/v9 ... 8937-4.jpg[/img]

This fan is wired to my E3D barrel fan on a switch so I turn it on when I start up and leave it on all the time. The fan is simply glued into the slot, it is almost a perfect friction fit. Now with the fan directed at my RAMBo, the board stays cool and I've printed for 100s of hours with many looooong 16+ hour prints with no "tat, tat, tat"! And, just to verify my hypothesis, I switched off the fan part way through a print and in about 10 minutes I started hearing the "tat, tat, tats" again. I flipped on the fan, manually assisted the extruder until the RAMBo cooled and I was back into flawless operation.

Now I think the symptoms make sense, I was seeing the stepper/extruder reverse during these skipped steps. Probably the thermal shutdown shuts off power from the stepper coils allowing the compressed filament to push back, thus reversing the rotation a few degrees.

Printed all weekend including 2 12hr prints with the grey filament with no issues. This seems to have solved my skipping extruder issue , I will ALWAYS have fans running on the board. THANKS!!!

Great, thanks for the update! Now we have 2 confirmed cases of extruder skipping that was caused by hot stepper drivers. Maybe something to add to the manual Gene?

I'll be posting this to thingiverse later today, but thought I'd share it here.

It's a new fan shroud for the E3D v5. I hated having to use kapton to secure the shroud, and I also got sick of having to move it every so often because it would start rattling/vibrating.

This fits the whole heatsink and has a c-clip that holds the whole shroud in place.

Tough thing to photograph, so hopefully you can see it clearly enough.

Cheers.

Good job on that! The C-Clip should make a world of difference.

Very nice and I'll probably print one for myself.

It would be nice though to have a E3D fan shroud that clips onto the hotend risers in the way that the SeeMeCNC one does, to keep it from rotating.

It doesn't rotate unless you want it to rotate. It's very snug.

Won't the c clip get hot there?

barry99705 wrote:Won't the c clip get hot there?

The bottom (hottest) cooling fin on an E3D is barely above room temperature with the stock fan blowing.

Eaglezsoar wrote:You did a nice looking and a neat job with the wires.
Great job!

Thanks

So this thread is becoming huge. It contains a lot of great information, but it's covering a lot of e3d topics now (extruder skips, mounting options, fan etc) Is there a possiblity of creating a new forum area dedicated to the e3d head?

McSlappy wrote:Is there a possiblity of creating a new forum area dedicated to the e3d head?

Please don't.

Some enterprising individual just needs to pull the good stuff from the thread, summarize it into a good first post and then start a new thread. There's a V5 now after all.

A good place to put relevant information about the E3D is in the wiki. Forum threads aren't quite as good for that.

Really? Couldn't we say the same for all of the separated threads we have? Slic3r etc?

The reason I suggest is that this thread is an awesome resource, but at 40 pages is a little daunting to read through. Where's the wiki?

Well ABS seemed to run beautifully through my e3d, but I'm having a heck of a time with PLA, which keeps jamming.

I've run it at temps from 165 to 220 (on the stock head I was running it at 180 if I remember) and I can get it to run fine with a manual extrusion through the nozzle all day, but as soon as I go to print I will get extruder skipping on the first layer, or very early on if that. So far I'm only managing to get the first layer even printed on about 1 of 5 prints.

It seems to jam after being idle for about 10 seconds, and when it does jam I can usually clear it by releasing the extruder roller and manually pulling it in reverse by 10mm then manually pushing it downward through the nozzle. It might take a few tries for this to work, but I can feel the initial resistance melting on the downward push and I'm able to keep manually pushing it through the nozzle as fast as I like. This works most of the time, but not always. I can guarantee a fix, by removing the filament, cutting of the melt-zone portion and reinserting it.

I've run it on Repetier Host .90 through to .95F and with slic3r up to 1.0RC3
My speed settings are 20mms on each (external perimeters and first layer are 80%) though I've tried it at 30mms as well.
Default extrusion width is .44mm and most others are set at .5mm
3mm retraction with no z lift
I have the e3d fan running all the time (hard wired to 12v on board)

Thoughts?

Also, why on earth is the latest slic3r now about 10 times slower than the version bundled with .90? This object I'm printing takes 12 seconds to slice in .90, but 1:50 in .95F! Others are taking 30 minutes and they aren't even complex.

McSlappy wrote: Also, why on earth is the latest slic3r now about 10 times slower than the version bundled with .90? This object I'm printing takes 12 seconds to slice in .90, but 1:50 in .95F! Others are taking 30 minutes and they aren't even complex.

It seems to get even worse with the 1.0 release candidates. The startup times are real bad for those compared to .99. Cura is many times faster but is missing some key features(mainly bridge detection/seperate bridging speed).

McSlappy, read my post about running a cooling fan on the RAMBo board to cool the extruder driver chip. When I was running ABS I never had a skipped step problem but then it started showing up randomly and then more consistently in PLA. It turned out to be the driver chip overheating causing momentary shut downs that appear as skipped steps (but if you watch the extruder, it actually reverses a bit).

I have a theory on this that has to do with the difference in shear thinning between PLA and ABS. I don't have the equipment time or inclination to test it though! But basically, start-stops and retracts impart a sudden force to the fluid filament. Materials behave differently when this happens. Assume that ABS behaves like most materials and actually thins when this force is applied - the extruder motor doesn't have to do more work. Now assume that PLA is different and either doesn't sheer thin at all, as much or actually thickens (a well known phenomenon) - in this case, the extruder has to do more work at each and every instance of this. If you just manually push the filament at the same rate by hand, all might seem well but the stat-stops and retracts are going to add up.

You also don't mention your extruder current setting in Repetier. Again, if the current is set too low, this effect could cause true skipped steps.

Cheers,
Michael

So, you're suggesting that PLA acts as a (*edit) NON-Newtonian fluid, but ABS does not? That would make so much sense based on when it seems to jam.
I read through the troubleshooting you did on that again (I admit I skimmed it before I had my e3d installed :/ ) Yes it sounds like you had the same issue as me. I've opened the door on the Rostock and have installed a 50cm fan in front of it. I have the fan wired to a wall outlet and I've set it to the '2' setting, which I assume is half speed. I tried '3' but it blew everything off my desk.

I am now preheating and running the print again.... Oh I hope it works

Also, the extruder current settings? Never even knew about that. It's set to:
#define MOTOR_CURRENT {175,175,175,200,0} // Values 0-255 (RAMBO 135 = ~0.75A, 185 = ~1A)
I think this is the correct line.

McSlappy wrote:Really? Couldn't we say the same for all of the separated threads we have? Slic3r etc?

The reason I suggest is that this thread is an awesome resource, but at 40 pages is a little daunting to read through. Where's the wiki?

FYI, there is a wiki: http://wiki.seemecnc.com that was created last fall. But there just hasn't been a lot of people adding material to it .

PLA is more likely to jam than ABS because it likes to enter a viscous (but not quite melted) state, in which it becomes fluid and swells due to heating. If it swells enough, it will sieze up inside the hot end. A key indicator that this is happening is that the filament will flow fine initially, but if left alone for a minute, becomes more and more resistant to being fed through the hot end.

Two things to look at are the barrel fan and the hot end. The fan shroud is very good at keeping the fins cool, and you should make sure the BOTTOM fin gets at least some air. If you don't install the fan shroud flush with the bottom of the hot end, which is a very easy mistake to make, it won't get enough cooling. I recommend taping the bottom with kapton so that no air can leak down and wash the hot end.

The second issue is fans blowing on the hot end. PLA does well with part cooling fans (especially on thin and overhanging features) but those cooling fans can easily remove heat from the hot end so fast that the heater has to stay on more to keep up with it. Part fans should never blow directly onto the hot end. You can try insulating the hot end on the sides with copper RTV. It's designed with radiative, uninsulated cooling in mind, so I don't know that it's a good idea to cover the whole thing, but at least the sides should help.

Finally, you could just have some filament that's particularly sensitive to humidity. Some filaments do best when kept in an airtight container with dessicants.

dpmacri wrote:FYI, there is a wiki: http://wiki.seemecnc.com that was created last fall. But there just hasn't been a lot of people adding material to it .

Ah, ok, thanks. Still 'wiki' seems like a manual in my mind and I'd hesitate adding to it since most of what I discuss here is work-in-progress-theoretical-type-stuff

626Pilot wrote:PLA is more likely to jam than ABS because it likes to enter a viscous (but not quite melted) state, in which it becomes fluid and swells due to heating. If it swells enough, it will sieze up inside the hot end.

Two things to look at are the barrel fan and the hot end. The fan shroud is very good at keeping the fins cool, and you should make sure the BOTTOM fin gets at least some air. If you don't install the fan shroud flush with the bottom of the hot end, which is a very easy mistake to make, it won't get enough cooling. I recommend taping the bottom with kapton so that no air can leak down and wash the hot end.

The second issue is fans blowing on the hot end. PLA does well with part cooling fans (especially on thin and overhanging features) but those cooling fans can easily remove heat from the hot end so fast that the heater has to stay on more to keep up with it. Part fans should never blow directly onto the hot end. You can try insulating the hot end on the sides with copper RTV. It's designed with radiative, uninsulated cooling in mind, so I don't know that it's a good idea to cover the whole thing, but at least the sides should help.

Finally, you could just have some filament that's particularly sensitive to humidity. Some filaments do best when kept in an airtight container with dessicants.

Funnily enough I'm actually trying to print a shroud (the awesome one that Cope posted), it's not that I need it, but it's a good test (overhang, small parts etc). The one I'm using now, does seem to cover it all, the lower fin is not hot at all, and it seems to have airflow over it.

Apart from this morning with this massive fan, I've not had a parts fan running at all (next upgrade) and I've been using some thin PVC sheeting to provide a breeze shield as it ran.

As of right now:
At 180 the filament seems to extrude no problems, but after about 10 seconds idle will skip, or if I begin the print, it'll skip straight away.
190 seems to allow it to extrude even after some time idle.
With the large fan running on the open door I have had no skipping.
I just turned off the large fan and closed the door, I'll see what happens in a few minutes.

Well it ran fine for 15 minutes, then it started skipping. Although it's not skipping, as in reversing or stopping the extruder, it seems to be turning fine, just stripping the indents off the filament, like there's a mechanical blockage at the hot-end. It seems to be having trouble with the parts that require lots of retraction - the small parts.

The extruder seems to be running very hot now too... Possibly the strain it's under - though it's not actually stopping it which is a plus I suppose.

... I canceled the print since I wasn't able to get it to feed nicely again by manually pushing/pulling the filament.
I restarted the exact same print file, and it skipped from the first layer. This would suggest to me a heat problem, since the extruder still seems to have no trouble turning, even if the filament wont.

Here's the canceled print, showing the point where it begins to skip lots with retraction or maybe heat.. or maybe not enough heat lol
[img]http://i.imgur.com/FoqOvEF.jpg?1[/img]

Here's a video showing the extruder skipping (is that even the right word, since it's really stripping the filament, not skipping) ... well I'll upload once my internet starts behaving...

Here's the vid:
http://videobam.com/AsivX

McSlappy wrote:Well it ran fine for 15 minutes, then it started skipping. Although it's not skipping, as in reversing or stopping the extruder, it seems to be turning fine, just stripping the indents off the filament, like there's a mechanical blockage at the hot-end. It seems to be having trouble with the parts that require lots of retraction - the small parts.

The extruder seems to be running very hot now too... Possibly the strain it's under - though it's not actually stopping it which is a plus I suppose.

have you tried the dust wiper/oily rag combo?

I have not tried the oily rag combo, though I did look at it for my last printer. Let me make sure I am talking about the same thing first I guess. You mean the rag/sponge with oil on it to pass the filament through so that it has less friction when it goes through the head right?

I really don't like this solution (sorry :/) it seems like it's patching a problem that shouldn't exist in the first place. I know that the e3d was designed with PLA in mind, so there must be some other issue I'm having with it... Do you use this setup with the e3d?

Don't suppose Sanjay still checks this? Perhaps I should message them directly.

if you print that shroud oriented that way, the c clip will snap, and you'll likely snap the main body.

Print it the way it's oriented, and use support.

I know this because I tried

McSlappy wrote:I have not tried the oily rag combo, though I did look at it for my last printer. Let me make sure I am talking about the same thing first I guess. You mean the rag/sponge with oil on it to pass the filament through so that it has less friction when it goes through the head right?

I really don't like this solution (sorry :/) it seems like it's patching a problem that shouldn't exist in the first place. I know that the e3d was designed with PLA in mind, so there must be some other issue I'm having with it... Do you use this setup with the e3d?

Don't suppose Sanjay still checks this? Perhaps I should message them directly.

I think it happens alot with the e3d, but its more has to do with the filament. i keep the oily rag on all the time now, i just drip a couple of drops in at the installation of the roll and forget about it. better safe then sorry