Hey everyone!

I just recently decided to build a enclosure for the taz for several reasons, but I’m having an issue with the filament getting chewed by the extruder. The question arises will the excessive heat contribute to the possibly of the filament becoming more malleable for the bolt to “chew” into it, the filament in question is abs. If this is due to the heat would a simple grid exhaust area fix this issue or would a small exhaust fan be more worthwhile. Thanks, Prime!
Picture of the case: Image url too bighttps://dl.dropboxusercontent.com/u/118631871/2015-05-18%2011.51.12.jpg

If you are getting filliament chewing, there are a couple possibilities.

  1. Your springs on your extruder idler arm are too loose or too tight.
    You want the spring width on the idler arm tensioning screws to be about 8mm. There is a printable guide available in this thread: https://forum.lulzbot.com/t/hobbed-bolt-clogging-filament-stuck/1739/1 that you can use as a template.

  2. Your extruder / hobbed bolt is clogged by stripped plastic and can no longer get a proper bite in the filliament so it ends up just sanding the filliment down. You want to make sure you clean all the shavings out of the idler arm chamber on the extruder. Make sure the bearings all turn properly. Use a small metal pointy thingy to get the plastic out of the grooves, etc.

  3. Your nozzle is too close to the bed / printed part. This is the most common reason for stripping. Plastic is a noncompressable liquid. if it can’t flow out the end at a sufficient rate, it builds up in the melt chamber and essentially acts as a brick wall when the extruder tries to put more melted plastic in that same area. If the parts are lifting off the bed at all, they can also cause that issue.

The heated enclosure should help with ligting. Be aware that you want to make sure your RAMBO board in the control box and the power supply should either be outside, or at least able to bring in cold air from outside, the enclosure. otherwise they can melt.

Great, not 100% sure on the tension for the idler arm but everything else should be working properly. The bolt has been cleaned of any “plastic shavings” in and around especially the grooved sections. I was thinking there would two options for the Rambo board plus the power supply unit; either i can move both outside with the Rambo in an external housing unit or i can add an intake/exhaust ports on the enclosure. Little quick paint up of the RED intake (possible low powered fans) Green exhaust slots(air scrubber?). https://dl.dropboxusercontent.com/u/118631871/2015-05-18%2011.51.12%20-%20Copy.jpg Any ideas on what the maximum temp for these two that would be tolerable, as it stands the case doesn’t seem to store heat with the only “hotspots” of air being around the hotbed*. The control box does blow out some cold air with the psu blowing slightly warmer air.

*Printing abs at regular temps

Edit: Now that I’m looking at the control box I may just be able to"transplant" the entire control box outside the enclosure given the cables are long enough. Any ideas if this would void warranty and if I should move the display as well?

I don’t know the maximum temperature, I do know that on just ambient air with a failed fan in the electronics box it is possible for the board to cook itself. The MOSfets seem to be the main culprit. No idea if moving the enclosure would void the warranty, but that’s what most people in that situation end up doing. That or building the enclosure with a cutout for the controller and sealing around it, using the back of the box as the inner wall. Power supplies are also prone to cooking inside an enclosure, but that should be easy enough to route outside.

The LCD “should” be fine as is. It is electronics so it is possible it will get annoyed with extra heat, but a failure there shouldn’t impact the machine, and a replacement board there is fairly inexpensive. The Rambo board on the other hand is not inexpensive.

Do you know the temp inside the enclosure? Any other method of heating up the interior besides the heated bed, motors and hotend?

I’m planning to build a similar enclosure from lexan. Venting the control board is definitely important… otherwise they wouldn’t fan right in front of it. The higher ambient temp will build up heat in the hobbed bolt… but I’d try increasing extrusion temps along with a turn or two on the idler. This should make sure the hotend is keeping up with your feed rate.

IT’s going to vary based on the size of your enclosure, ambient temperature, heat bed and hot end type and temperature, how well it’s sealed, etc. A small mostly conformal enclosure will probably keep the surrounding air 15-30 degrees above ambient.

Some people have experemented with sun lamps, with limited success. They either tend to only spot heat in one place, or raise the heat too much resulting in deformed parts.

You can always test the effects of an enclosure by taping a couple turkey roasting bags around your TAZ and printing something. That actually works pretty well.

Yeah… I have to agree. Probably unlikely that an enclosure is trapping enough heat for the hobbed bolt to soften the filament. I’d still play on the safe side and allow the electronics enclosure fan to suck in some cooler air.

Maybe I’ll try a garbage bag to trap heat as a compare and contrast to efficiency of acrylic. As the temps warm in the house the enclosure project is not as urgent. I’m shooting for an ambient temp of 80-85F (27-30C) in the enclosure… I think that’s all I need to cure my minimal warping on large parts.

I tend to aim for around 85-90F as that has seem to be warm enough to prevent most delamination and adhesion issues I have had so far. I figure that is within the safe operating temps for the Rambo. Otherwise I think I would have to stop printing during the summer time when it gets hotter than that. :cry:

I don’t have any way to measure the average temp while running sorry! I can tell you for sure though that the enclosure is far from being air tight and should leak a fair amount of hot air in the corners and joints. (you could use a high grade silicone to secure the corners, but i like to be able to take mine apart) If it helps at all the printer is being used in Florida at around a 80-90F ambient room/outside temp. I would estimate that the temp inside especially around the hotbed can be in the higher 90’s with the air around control box/psu hovering around lower 90’s- mid 80’s. Of course this would change depending on the time the printer was running, but the hottest i have felt would be the above temps.

This was the exhaust/air scrubber i was looking to install which would remove some of the internal heat and abs fumes from the enclosure. Still haven’t had time to test if the filament was still getting chewed, so i will reply back if it is still getting chewed later today! Link for airscrubber: http://www.thingiverse.com/thing:125264

Edit-Just finished moving the control box and the panel outside of the enclosure. Would recommend finding/making an extension for the wires for better fitting. Started a print time to see what happens!

During a 13 hour print around the 9-10ish hour mark the filament again began to get chewed by the bolt, any ideas on somehow cooling the bolt? The filament does not become clogged in the nozzle at all, just simply starts to get “eaten” by the grooved section of the hobbed bolt. The grooves are all cleaned any other ideas, thanks Prime!

Hmm… that sucks. Maybe the 80x80 fan mount created by a user could help… I think the user name was JLC_Designs. It allows for an 80x80 box fan to be mounted in front of the extruder and more specifically the hotend heatsink. A bit overkill if you ask me, but could be he only way to cool the hobbed bolt.

Have you tried venting the enclosure a bit? Remove a few screws from the top and crack by half an inch… Sucks to experiment on a 18hr print. Get a thermometer to get a quantitative reading.

The bolt becming too warm probably isn’t the issue. If it were getting that hot (200 degrees c at least) you would also be getting a huge amount of heat transfer to the bearings, which would in turn be melting your extruder body.

What you might be running into instead is either lifting, overextrusion, or retraction related issues particularily if you are printing a honycomb infill pattern.

Lifting on a large print like that is often what scuttles them. the top layer only has to raise a very small amount before it can effectivly block the nozzle long enough for the fillament to strip out. Check your base and layers for any separation. if there is any, that might be the culprit right there.

Overextrusion is a bit harder to nail down. if you are printing something with a high level of infil and failing fairly far into the print, you might have the filliament diameter or even the extruder firmware esteps slightly off. When printing a very large object, that very small excess fillament builds up each layer. The first 40 layers are at the 95% infil you specified, but by layer 200 you are actually effectivly printing 100% infil, and as soon as it gets above 100% the nozzle starts having difficulty getting rid of the excess plastic and eventually blocks. If your printer prints fine on smaller prints but only has issues on larger prints and isn’t lifting at all, that might be what you need to look at.

the retraction issue is another one that is very hard to nail down, but I find it usually shows up when printing hexagon infil since the nozzle wants to retract on every single leg of the hexagon shape. If your infil has a bunch of short sharp retractions in a very small amount of space, the fillament basically gets sanded down to nothing. You can try adjusting your retraction rates to counter that, but I just avoid printing hexagon infil on large parts whenever I can.

I tried to print in a different material and so far have experienced similar results. Both types of filament thus far (abs/pla) have experience chewing with the abs facing much more definition in the amount worn off. Reading over the suggestions I have several things to attempt primarily looking into lifting of the print OR the chance of a unleveled bed somehow. Piercet stated some excellent points of why the bolt wouldn’t be getting hot and it is fairly cool to the touch upon inspection while the printer is still running. The over extrusion shouldn’t be the issue as I tried three different prints with different models and plastics and have achieve similar results. One said print was attempting to print a hallow tube with 0% infill that “jammed” half way through; so I’ll try to see if the printer is somehow unleveled overnight which could of cased an issue.

Also i have left the printer door open during a print with similar results, next step i could try is completely removing the front panel for the duration of a print.

If you’ve tried printing with the door open then it’s not the hobbed bolt heating up. What temp ate you extruding the ABS? The Cura profiles from LB might be a little low for the hexagon hotend… I print ABS between 240-245C.

Also petform the normal checks:

  • Sample the filament diameter and check the settings I’m slicing software.
  • Make sure the heatsink fan is on all the time.

I haven’t had the chance to perform the other checks on the printer yet, so I’ll go ahead and tell you the temps I print the filaments at Abs 240 Pla 205. I’m also using cura and a print that was printing fine before the machine was introduced into the enclosure. The fans are all still operating at their intended capacity. Gonna check on the bed level and perhaps turn the temp up on some of the filaments later today will post back with the results! Thanks, Prime.

Edit: The bed is perfectly leveled and there shouldn’t be any areas that “block” the extruder. Attempted a print with lower feed rate/ higher movement rate in attempts to “clear” the plastic from the nozzle faster which achieved similar results as before. Contacted support to get their two cents on this issue. Attempting to reprint the slower feed rate print to see results again.

Thought i would update this post if anyone was having similar issues. Any who i found out the culprit was this residue which I have begun calling “sap” that can only be the result of using this wood filament. No idea how old the wood filament is or any possible other reason it has left this really sticky clear residue. The filament would build up on this slowly depending on the temp eventually clogging the nozzle. At least i believe that this is cause I’ll update this post if anymore issues occur!

Hi, Sorry can you clarify please. I thought you said you were printing in ABS/ PLA? I have been having major clogging issues and have spent more time fixing my TAZ5 than printing since purchasing in April. I have had “clogs” with ABS, PLA and HIPS on the hexagon head and original Budaschnozzle2. Started without enclosure, thought it might be drafty so enclosed. Have gradually implemented the lulzbot guides, mhackney guides https://forum.lulzbot.com/t/strategies-for-resolving-print-artifacts/1400/1 richrap guides http://richrap.blogspot.com.au/2012/01/slic3r-is-nicer-part-1-settings-and.html, Triffid Hunters guide http://reprap.org/wiki/Triffid_Hunter’s_Calibration_Guide and alexrj’s guide https://github.com/alexrj/Slic3r/wiki/Calibration among others. I have made separate copies of the firmware with settings (e-steps, PID autotune settings etc) for each extruder. As one clogs i swap it out to clean it. I have measured the filament diameter and recorded the average (all filament still that bought with printer from lulzbot). I have adjusted the idler tension to ~4mm (saw this in forum/ lulzbot guides somewhere and supported by richrap i think, but above suggests 8mm between washers. For the hexagon the fan is constantly on and aimed more towards the base of the cooling fins. I have setup individual slic3r configs for each combination of filament and extruder and quality (though only using medium so far) based on the lulzbot slic3r profiles. I re-level my bed using 80gsm sheet of paper starting with all corners mid level, z-stop at home, 2 circuits around the corners, then 2 or 3 circuits around the middle of each edge useing a “buble level” to adjust the corresponding corners up or down, then another corner circuit followed by finally adjusting the z-stop in the center of my print area so the nozzle is not touching and there is some perceptible resistance at the corners (bowing of z axis bars). I thought i had it solved this time, was getting almost perfect calibration prints. 10mm cube at 9.97 +/- 0.05, 40x10mm single width wall adhering beautifully and wall width within 0.01mm of 0.35 on all 4 sides. Printed a number of small items without problems, all <1 hour prints. Ran a 3 hour print http://www.thingiverse.com/thing:756215 without problems, its dimensions a little out so adjusted and ran again. Found printer happily in finished position with the print having only half completed. Checked model/ gcode seems OK. nozzle extruding poorly, pulls off to one side much finer than should be. Cold pulls, scrub nozzle with isopropyl alcohol, clear hobed bolt, manual extrude. Appears to have fixed it so print another couple of small items without any problems. try the longer print again (re-sliced), pay closer attention at 1.5 hour mark, extruder suddenly doing “dry print”. Repeat above with similiar results. Third attempt to clean can’t get it to extrude properly, remains thin stream and pulling off to side. Unfortunately using HIPS ad have been unable to clear nozzle after soaking in limonene (and acetone and alcohol and caustic soda …) and heating with heat gun/ blow torch/ solder iron. broken 2 0.35mm drill bits and 1 0.3mm bit trying to clear nozzle. Now waiting for new nozzle (nozzle’s :frowning: ) to arrive. All of the clogs have followed a similar pattern starting with the hexagon hot end straight out of the box, prints well for a while then clogs on long print, continues to print small items OK but fails on big items. I noted a slight mis-alignment of the hobed bolt teeth with the extruder hole initially and removed a washer for better alignment, now check this each disassembly - reassembly and have a length of ABS to maintain alignment when tightening. I noticed on one occasion that there was some "spreading’ of filament into a small gap at the junction of the aluminium base plate and plastic extruder with the hexagon head and this last clog there was difficulty advancing the filament beyond what appeared to be this point but easy to pull it out. I haven’t yet addresed the “heat creep” possibility because it was happening with both extruder types, but once i get an extruder up and running i am intending to put a bigger fan on to try this.

I can not think of anything else and was hopeing someone might have some further suggestions or could direct me to further information on the topic. i am being driven to drink by this damn thing, and i cant afford to be an alcoholic!


Wow… You need to start a new thread… Copy your post and paste in a new topic. You’ll get more traction.

A few more things to try:

  • increase extrusion temp
  • tighten the idler.
  • make sure filament is coming off the spool properly… no binding

Are you able to print one filament material better than the other… ABS seems to print the easiest on the TAZ. PLA seems to be subject to heat creep… Havent heard as Mich about HIPS.

The last thing to check is the align!entire of the extruder body to the hotend opening. If not aligned, the filament could rubbing against the wall of hotend or extruder… More friction means more force to feed the filament. Tighteing the idler may solve this, but disassembling and reassembling could fix the alignment issue (use a small length of filament in the hotend to act as a guide to align the extruder.

Hope that helps… Sounds like you nailed any other issues.

Hey! Sorry for the late reply, but was/am printing in ABS/PLA. Prior to these clogging issues i was printing in a filament trial test that included woodfill. The woodfill left a residue that would be akin to sap and would clog the nozzle. Another note that i think you should check is the filament and its overall quality. Checking the quality of the filament would be easily done via cutting several sections from the spool with a pair of pliers/cutters. Once a few sections of around 8-10 inches each have been cut away from one another bend the sections in half until the filament snaps without binding/smashing the filament(the may be repeated until the sections snaps off naturally). This should achieve a “clean” unaltered breakage of the inside of the filament allow you to see any errors or voids. A poor grade of filament may have these voids causing air pockets and clogs to appear. Continue snapping the filament sections into about a total of 4-8 pieces per sections to check for any errors or voids. The following photo shows illustrations of the voids that can appear and will range in size. A better grade filament or trusted supplier would be your best bet in getting no voided filament. This is the only other thing that i can find that is causing my clogging issues. If you need anymore info let me know!

I have personally experience several clogs again due to the cheap filament possessing voids that can be seen in the “bubbled” end of the filament where the clog occurs.

Cheers @kcchen_00, i was having a bad day…
I have had the idlers as tight as i can get them by hand, just getting to 4mm between washers. Doesn’t seem to make a difference as initially i had them pretty loose.
I have tried turning the temp up (to over 250 degC) on some of the bad days :cry: but it didn’t seem to make a difference to the partial clog already present.
I have had a few issues with spool binding, i think i solved that with the enclosure and overhead spool holder but not 100% sure!
I have disassembled and re-assembled 4 extruders so many times i think i could do it with my eye’s closed, i generally use a bit of ABS or the 2.5mm/ 3.0mm allen key to “hold” the alignment though i am looking at finding something a little “Tighter”. My first extruder did seem to have an extra washer pushing the “hole” a little off to one side of the ?“hobbs” of the hobbed bolt, so i check that alignment constantly now.
i have noticed an apparent catch at the border between the aluminium base and the body which i haven’t figured out yet. Going to work on the “heat creep” when i “calm down” :slight_smile: .

Thanks @primewire All of the filament i have came from lulzbot with the printer (though i do have some PVA on the way from an alternate supplier). Looking at your photo i haven’t seen that, with all the clogs i have had the “opportunity” to chop and snap bits of ABS/ PLA/ HIPS up regularly!
The reason i asked about the “residue” is that i have noticed that the nozzle seems to develop a “sappy” (lucent yellowish) residue on it and i have only printed with ABS, PLA and HIPS. i hadn’t really payed any attention to which filament produces it or if there is any difference.

Anyway, i had shut the door of the workshop before i posted above and haven’t been back in! Should have calmed down in another couple of days. Got to figure out windows again (new computer) and lost my “custom” (PID settings/ e-steps etc) firmware in the swap so should have sorted that out before my new “stuff” arrives.
Have bought an entirely new single extruder, a couple of AO hexagon heads and a pile of nozzles and wapping big fans! (think ill need to upgrade the power supply!) so that should arrive soon.
Think the best thing is to stick to one extruder and one material and learn it “intimately” (so to speak).

BTW any hints as to unclogging PVA - soaking it alternately in Acetone/ D-Limonene/ MEK/ Caustic Soda (?Lye) but not much luck so far. Might have to “borrow” some Hydrochloric Acid from work.

Thanks for the help