Jamming and more Jamming

#1

I’ve been having a lot of trouble with the extruders and cartridges jamming up. I had one of the provided PLA cartridges jam to the point of breaking trying to extract filament. Tonight I had a jam in the extruder to the point that I could not retract the filament, nor force it through, and final ended up disassembling the print head to clear it. I hate the thought of repeating this process, as the extruder nozzle holders are very soft aluminum, and the threads took about an hour to get to mesh by hand without striping/cross threading.

Is anyone else encountering an inordinate number of jams with this machine? I’m curious if there are any tricks to work around the issue. I’m going to give it a couple of more goes and then enter a support ticket if it continues. It’s my first 3d printer, so I’m not sure what is normal for these things.

#2

I’m currently fighting to get mine to feed as well. I had it stop feeding and have taken the top apart but still can’t get it to feed correctly. If I manually pull the filament out of the cartridge and put it into the top of the extruder its fine. It just won’t feed it through the teflon tube. It was working fine and then it just stopped working at all on Sunday. I’m going to try using a different cartrige and see if that fixes it before I tear the bottom section apart. If you find a solution let me know.

#3

When I disassembled the head, I found the heatshrinked heater wire connection on the jammed extruder was loose, only held together by the heat shrink. I’m hoping this was making a poor connection and causing the jams in the “jammed extruder” case. A few more prints will tell. Certainly the cartridges also jam easily, and the design of using such a small diameter spool seems a bit suspect to me.

#4

Found the problem with my printer jamming was the plastic tip on the cartridge had broken so it wasn’t getting good contact with the little drive gear. Switch cartridges and it fixed the problem, but now I have a broken cartridge that is mostly full.

#5

I’ve had every cartridge I put in the zim become either very stressed (I.e.plastic discoloring/cracking around stress point), or break at the tip that inserts under the stepper gear. The refillable cartridges wont last given the stress issue. This is certainly a weak point in the design. I was thinking of making up some little shim that could be printed or machined to sit under that stepper gear and relieve some stress. I’ll post if I have any results.

#6

That would be very helpful. I have found that if I feed the plastic through the teflon tube by hand that allows me to use the damaged cartridges but if you find something we can print to fix the problem that would be great.

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#8

@jpod and @scientsit434 I had jamming problems as well… normally when I’m jamming it’s a good thing, good beat, lots of work getting done… but in this case, not so much.

I was getting the PLA completely melted inside of the print head.

Turns out that my feeder fan, the one that keeps the feed compartment cool, was not running… and in the case of short prints it was fine. But longer prints allowed that compartment to heat up to the point where PLA would just come in and melt, thereby jamming.

The large ribbon cable that goes up to the print head has a connection to control that fan, and it just so happened to have a terminal without a locking tab on it (so that pin that controls the fan had popped loose and was an open connection). After fixing this, it printed long prints just fine.

With the latest firmware (or since v1.1), your feed fan should turn on whenever either extruder temperature is above 70C, and only turn off when both extruders are below 45 or something… I forget the exact turn off temp. So as your extruders are warming up, pay attention and see if your fan kicks on or not.

#9

Thanks BDub, good to know. I’ve been getting fairly consistent results now that I’ve learned a bit about the Zim and fixed some of the manufacturing flaws. That ribbon cable to the head looked like another area of concern. We’ll have to watch that area. Certainly the printer cartridge weakness and bottom feed stepper need a bit of thought.

We be jammin! Hope you like jammin too, but not while print-in!

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#10

Something else I’ve noticed on the subject of jamming. It is very clear the Zim sometimes gets it’s left extruder and right extruder backwards. I haven’t found a reproducer yet, but when starting a print, if I see the wrong extruder start to heat up, I usually cancel the print and reset the Zim. I’m curious if this were allowed to proceed, if the correct feed tube would actually be used (i.e. the unheated one). If so, that seems like another potential cause for jams.

#11

I’ve had it heat up the wrong head before. The one time I didn’t catch that it was the wrong extruder, it started printing the previous print that I had done (using the wrong extruder AND wrong file/gcode).

I haven’t had any jamming yet and hope not to. Disassembling the head seems like a chore.

#12

I’ve had it print with the wrong head as well. For me it actually just prints the entire last print with which ever head it feels like. I just watch to see which head is heating up and if its the wrong one I just restart the Zim.

On the jamming note I have discovered that the bottom feed motor is mostly useless, I have to let it pull in a few inches of filament when loading them take the cartridge out and manually feed the filament to the head by hand them put the cartridge back in.

On this note I have ordered two small maker bot spools from newegg and am going to try and see if I can build a mount for them that goes on top of the zim and feeds directly to the extruder skipping there entire feed system. If I have any luck I will post directions and files.

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#13

Great idea scientist. I’ve thought about creating an entirely new feed mechanism as well. Having the spools hidden away down there is not really all that important to me, as long as the feed works, and the long teflon tube wrapped all over the place is causing more problems than it esthetically solves IMHO. I’ll be curious to hear what you find out with a remount, and will post if I can come up with any alternatives as well.

One thing I think I’ve noticed is that it only gets the extruder wrong after I’ve already printed something. The first print after a restart always works for me. Choosing a preselected model always fails on extruder 2. I’ve taken a look at the Perl code that manages the extruders on the 1.2 image, but nothing jumped out at me. If we can come up with steps to reproduce, it may be easier to at least avoid the issue. It is certainly a hassle when you have the platform all prepped, model sliced, and getting ready for a print, and then you see the wrong extruder heating up. I’ll try to make some notes and see if I can identify when the wrong extruder is being selected.

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#14

I’m back in the doghouse, jammed after trying to print an xmas ornament. I didn’t even get the first part printed and it jammed after 20 minutes or so of printing. Different failure mode this time. I believe the o-ring that goes around the filament jammed it up and the filament broke down near the bottom of the feed tube. I then just tried to fix the cartridge and reload it (but did not clear the piece of filament that was still in the nozzle) … this prevented it from working again because the filament was not able to engage with the feeder motor in the extruder. Good thing too, because if it had it surely would have not pushed that broken piece through and would have gotten all tangled up in the feeder area. This stuff is hard to describe, so if you know what I’m talking about you get it… if not you are probably like WTF is he talking about??? Pardon me for not elborating on Xmas Eve… I have stuff to do! :smile:

Despite clearing the broken piece, reloading the filament at 230C, finding the new zim/extruder_control menu that replaced the zim/pronterface# menu, this thing still won’t squirt black PLA. Sigh…

#15

I hear ya BDub. I’ve had the filament break inside the teflon tube above the gantry a couple of times when not using that particular extruder. I’ve found simply running the prime sequence still works, even with the break in filament going through the extruder. I usually run through the break prior to attempting to print with that extruder.

I had my black PLA cartridge jam and pulled it apart, and that small black o-ring was totally floating around inside the cartridge and wasn’t even wrapped around the filament. I relegated this to kickstarter “gotta ship before Christmas” quality control, and reseated it in the slot around the PLA, and that cartridge has worked since for several prints.

These printers still take a bit of TLC. Do your x-mas eve stuff, then give it another shot. It will probably work this time. Good luck, and Merry Christmas!

#16

I tried a bit longer to debug it… and pulled the nozzle out again and tried to get PLA feed through the extruder. It kept stopping right at the stepper motor in the print head. I’m guessing it’s not operating, likely due to a bad main cable that I patched up. I got a new cable to replace it from Zeepro, so that’s next on my holiday break list of things to do :wink: I don’t see how this problem is related to the PLA breaking near the cartridge though and then the broken off piece being consumed in a print. So it’s failing wickedly.

I am also honestly considering just feeding this printer from the top with a spool on a caddy hung on the back of the printer. However that kind of screws up the awexomeness of the design… so if I can just get it working and keep it working for a long period of time it won’t have to come to that.

BTW: The plastic that the cartridges are made out of is very soft… so those tabs break off way too easily. Be careful if you have to open one up!

I’m good at TLC when I can spare the time… so hopefully that will be over the next couple days. Merry Christmas @jpod and also the rest of you Zeeproers!

#17

You might try putting a small black mark on the axles on the back of the extruder steppers using a Sharpie. I did this to mine, and makes it clear which stepper is running and how fast. One thing to be aware of about the design is that the stepper is used on the opposite side of the head assembly from the extruder being used (i.e left extruder is being used, look at the axle on the right stepper to ensure it is moving).

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#18

That’s smart! I’ll definitely put some marks on mine. Still haven’t got back to this with all of the Holiday Cheer going around :slight_smile: