Looking for a general recommendation

Well here is the story:

I bought a Taz4, late last year. Pretty early on, I had an extrusion issue (filament stripping). It had turned out that a small section of the filament guide tube was accidentally pinched off and slid down inside the extruder. But, before I found that, I had assumed it was a nozzle clog. I hastily removed the nozzle when the nozzle was too hot and I damaged the threads of the nozzle and the threaded extension. Furthermore, I carbonized some plastic in the nozzle, trying to heat it up to clear the clog (forgive me, at the time I was quite new to all this).

Since then, the only change I made to the printer was a PEI bed surface (which, unfortunately seems, as I suspect, to be a little thicker in the center of the sheet than at the edges).

The recommendation I’m looking for is mainly: what to do now. Should I just break down and replace the nozzle and threaded extension?

It seems that I cannot get consistently good prints. I constantly am readjusting Slic3r settings. And am usually successful (eventually) at getting a few good quality prints. But, then all of a sudden, the quality drops severely and I have to fiddle some more. This usually results in me dropping speeds. It is now at the point that I am printing ABS at very low speed (20-60mm/s). The nozzle does not fully clog often, but I get all kinds of weird stuff happening.

I just removed my nozzle again, because I did get a clog. More carefully (as I am now) I meticulously brushed away every bit of carbonized plastic I could reach with a brush and then picked away the rest with a needle the gunk that was way down next to my .35mm hole.

However, I am still not getting great quality. My plan tonight is to go back to some Lulzbot recommended Slic3r configs and restart there, the see if I actually managed to revitalize my nozzle, and maybe the configs I was using is just now too modified to print well with the cleaned up nozzle.

So, how does this sound? Does replacing the nozzle and extension make sense? Can damaged threads really make for such unreliable prints, even after a careful cleanup inside the nozzle? I’m worried I’ll replace the nozzle and find I’m still not printing well (I couldn’t possibly go through all the quality issues I have at random).

I’d buy one of the new Hexagon hotends or maybe an E3D V6 if I was in your shoes there.

How did you damage the threads? Can you post photos. I can’t imagine that slightly damaged threads would be the cause of these issues unless you are getting nozzle leakage from them OR you ross threaded the nozzle and it is not on straight.

Good photos would help a lot.

Unfortunately I don’t have any photos for you. I’m away for the day, so I can’t take any.

But, I can say that the damage to the threads was relatively minor. The parts still thread together smoothly. I think the issue I had as a result of the thread damage might have been limited to burrs getting into the flow of plastic.

The carbonized plastic was pretty intimidating though. I don’t know what others consider “bad,” but it looked pretty dirty.

Anyway, 99% of that is cleaned up. And, like I said, I’m gonna try some Slic3r configs available for download from Lulzbot as a baseline to start over. I think maybe I was compensating for lots of friction.

However, I am beginning to feel hopeless with this extruder. After cleanup last night, I ran a print. It finished, but the top surface was bumpy and rough. Perimeters on the holes were raised in comparison to the top infill, even though they are supposed to be level. The external perimeter was a bit blobby. It just seems every time I get a slic3r profile that prints an item of good quality, the quality lasts for a while and then my prints all of a sudden look crappy again.

Hard to tell. Could be as simple as calibrating your esteps. It could be a bunch of other rabbit holes as well. If I had a problem that was intermittently happening I wouldn’t start with software. I would use a stock slicer profile and moderate speeds and actually watch the machine work, like really closely. Print a test piece that can test all sorts of different aspects of a printer–like x axis backlash, y axis backlash, wobble etcetera.

I would venture to guess that something hardware related is loose or weird in some way. Maybe start with checking the backlash on the x,y,&z axes. It only takes a couple of minutes and requires no tools or only a machinists ruler. There are a few threads on issues with slop in the IGUS bearings messing up peoples prints.

You may be on to something with your nozzle being messed up. In my little experience I’ve found that the condition of the nozzle plays a big part in print quality. One of the best things I’ve done for my print quality is get a hexagon nozzle–still working with the E3D-V6 but it is working out really well so far.

Yep. All great suggestions…you WILL get the problem fixed, just have to take your time and cover all the bases, go through things systematically, first step I would do are to make sure everything is in alignment, no bearings loose, belts tight, all the routine stuff, then go further into software and slic3r settings, step by step, check marks as you go.

Well, I think I have eliminated most of what my problems were. I got a little tired with making small adjustments, so I did some major tune-up, hoping for good results, and I’m happy with the improvement (so far - cross fingers for continued success)

I took my nozzle off and went mad on it. I ground down some damage on the top surface (wrench deformed it a tad) so it sits flush again against the heater block. Then I proceeded to remove all possible crap I could, despite it being very difficult to reach way down in the nozzle, even with a small brush. A needle left some marks in the nozzle, as I was picking out some charred plastic, so I polished the inside with a q-tip and some aluminum polish.

I put the nozzle back on and ran some eSun cleaning filament through it. To my surprise, I was still pushing gunk out of the nozzle. But after about a meter, I stopped seeing black specks come out.

Then, I tried to adjust the tension on my idler now that the nozzle should have been free of constrictions and much friction. Unfortunately, I may just need more practice with this part. Extruding filament at 150mm/s (Lulzbot’s recommended speed for adjust idler tension to), I could not extrude without hearing a distinct clicking noise, even over a wide range of adjustments.

Anyway, I moved on, because I could not see that the filament was slipping any, just making an occasional click-click sound. It turns out my E-steps/mm were slightly off. I just sort of trusted the factory calibration to this point, but apparently it was either mis-calibrated, or it went out of whack at some point. The difference was about 3% (extruded only 97mm when I gave a command for 100mm).

I also cleaned the x and y shafts off of any debris. However, I did not change any belt tightness. I’m not sure if there is any better way of knowing if things are tight enough, but I moved the carriage around my hand, and there seemed to be no slop at all.

Finally, I hit my PEI bed with some 800 Grit and then 2000 Grit sandpaper. gave it a fresh surface.


The problems with the surface quality now are such that I can at least say what my issue probably is. The surface quality of my parts had been much worse at times, so this is a delightful improvement over some other parts I have seen. I noticed my blue filament popping out the nozzle like it has picked up some moisture. Also, my blue filament seems to have some pretty poor tolerances. It is quite oval (calipers show changing dimensions when rotating in a single spot around the center axis). Also, the blue filament seems to range anywhere from 2.75mm to 3.2mm, yikes. I got the filament from IC3D because it is an inexpensive ABS and I had heard a few good things as far as acceptable quality for the price, but I don’t think I’ll be buying any more of it.

You’re coming along…still sounds like there’s something going on with the extruder, if you’re clicking at 150mm/s, that’s sort of fast, is that the speed you are printing with? I usually don’t go past 80, if it’s a large print, few details and I don’t care about surface quality, then I’ll do 100, I’ve never went higher…

belts sounds tight, check pulleys and set screws, and also all the screws like for the Y belt holder and your bearing holders…

Those prints don’t look too bad, just looks like a bit of wave in the surfaces, almost like it’s cooling in a non uniform way, could be the extruder actin up also, but overall, I’ve seen worse.

by the way, with regards to crappy filament. Oval, distorted, $hitty filament can RUIN extruders and it can RUIN your printing experience, I’d just chuck it. I never realized how crucial filament quality was until I ran into a bad roll… check out this thread…

https://forum.lulzbot.com/t/rough-prints-weird/1434/1

I couldn’t figure out why all of a sudden are started to get bad prints on the same roll when I was getting perfect prints a little while earlier and everything on my Taz was tip top…turned out it was the filament. Apparently they discontinued it due to quality issues. It was the creative series from filaments.ca

Just wanted to poke my head in here - I noticed a complaint about the PEI being thicker in the center than the sides, and I think it’s a different problem - X-axis droop. I just (literally about an hour ago) swapped out my pillow bushings and guide rods for ball bearing bushings and hardened rods, and OH MAN, what a difference. I printed a nearly flawless 80mm/s print at .3mm layer height, on the ‘floppier’ (front) extruder of a dual extruder, with my acceleration jacked up to about 1300.

Also, my ‘bed’ is now totally level. Especially with the heavier dual extruder, I’d noticed a lot of droop in the center - that’s gone now.

For reference, I’d previously been printing this material closer to 30mm/s, as it was the only way to get good results with it.

I also recently recalibrated my esteps - I guess I’d somehow been using the default esteps, even though I was now using a totally different (half height) motor. I went from something like 834 to 772. Somewhere in the range of 8% off!

As to filament - these days I just get all my filament from matterhackers.com. They’ve never sent me a bad roll. I tried IC3D and Jet when I first got the printer, and had nothing but problems with them.

@mushoo
Glad to hear the upgrade worked out for you dude. I feel the same way about jet filament. I ordered ABS from them and got two rolls of HIPS. What are you using as a mount for your E3D? You were right about the other one coming loose.
@jb
I hear you there I’m now trying to print on the crappy section of what used to be a good roll. Super frustrating!

@brew: My E3D mount is the same as the one you’re using, I think. Well, one of them is. I have a Volcano and a regular E3D - the regular E3D has my custom mount plate, but the Volcano is taller so I printed up a new extruder just for that one - basically the same extruder body as the Hexagon hotend, no need for a custom plate. I did have to print up a J-head plate for it, though.

Once I move on to the Chimera it’s going to have to be a totally custom X-chassis mount, though. That thing is weird.

obviously you guys seen my thread on the crappy creative series filament from filaments.ca…half roll ok, bottom half was oval :slight_smile: frustrating indeed if you don’t know what’s going on. Can reek havic on your extruder too if it’s bad enough.