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billdempsey

Bowden tube pop unplugged the temperature regulator

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I've been battling with the Bowden tube for about 8 hours now. It continues to pop out when I try to print. Unfortunately, on one attempt where I left the room for 5 min, the Bowden tube pulled so far out that it pulled the connector on the temperature regulator out of its socket. The hot end got so hot that it partially melted the Peek. It's been oozing more and more around the brass, too. I pushed the brass back into the Peek as it cooled, and it stayed there (for now.) I've tried using nylon ties to hold the Bowden tube. I've tried roughing up the surface and wrapping coil winding wire around it below the clamp & blue horseshoe. I've gotten so desperate that I tried to drill a small hole in the top of the peek to put a set screw into a notch in the tube to hold it in place. Didn't work, just mangled it.

Nothing has worked, and the various parts are in poor condition now from all of my attempts at fixing the Bowden problem. Even the tube itself is scarred up from me using pliers over and over to shove it through to the peek. I've made a mess of it while trying to fix this issue. I so wish they had pre-assembled/tested units 9 days ago when I ordered. I would have bought one.

Ok, unless anyone has another idea I can try, it looks like I need to order a new print assembly and Bowden tube after all this. Anyone know do I go about doing that? The store doesn't list very much in the way of replacement parts.

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Yeah, that would definitely work or a nut on both sides of the top piece tightened toward one another.Would I use a die to thread the plastic tube? Any idea what the OD is on this tube?

If I could just get it to print a few times, I could print out a better clamp system I found on Thingiverse. This is definitely a chicken and egg situation. I'll keep trying to figure it out.

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Get in touch with UM. I had a run away on mine that was a result of the same problem and they replaced the PEEK for me. Given your troubles, they may provide you with an additional bowden. Also, check to make sure you have the comb part on the top of the print head over the amplification board DIRECTLY over the three prong socket. I believe the Wiki had it reversed at one point (maybe it still does).

After that, figure out why the tube is popping. The most common instance would be plugs forming at the PFTE to bowden. I would be sure to check your retraction settings, if you are using retraction, as you may be pulling molten PLA up into the PFTE piece, thus creating plugs. The next thing I would check too is that you aren't over tightening the four cap bolts that hold the print head together. I think that's a VERY easy thing to do because we are all worried about it leaking. In reality, this can overcompress the bowden, which can create plugs. There is not a lot of force necessary in tightening those four long screws to provide a leak free unit. The other thing I would check is that you haven't applied too much pressure with the extruder to deform the PLA as that can cause a plug as well. This is much more rare on the spring and bearing extruders. Then, consider printing faster so as to push the filament out quicker, thus not allowing as much of a molten PLA build up. Conversely, you could lower the temp you are printing at. Finally, consider active cooling.

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Finally yanked out the clamp up top and just put an M3 through the wood and into a hole on the side of the tube. Here is a pic of my butchered print head. 5a330d1c5fabf_Piceassembl.thumb.jpg.fb004a642ab90a5cb606ee7087e78271.jpg

It's ugly, but it's finally printing. Having trouble with globbing and brown ooze above aluminum block now. Been playing with settings to try to fix those issues now.

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Get in touch with UM. I had a run away on mine that was a result of the same problem and they replaced the PEEK for me. Given your troubles, they may provide you with an additional bowden. Also, check to make sure you have the comb part on the top of the print head over the amplification board DIRECTLY over the three prong socket. I believe the Wiki had it reversed at one point (maybe it still does).

After that, figure out why the tube is popping. The most common instance would be plugs forming at the PFTE to bowden. I would be sure to check your retraction settings, if you are using retraction, as you may be pulling molten PLA up into the PFTE piece, thus creating plugs. The next thing I would check too is that you aren't over tightening the four cap bolts that hold the print head together. I think that's a VERY easy thing to do because we are all worried about it leaking. In reality, this can overcompress the bowden, which can create plugs. There is not a lot of force necessary in tightening those four long screws to provide a leak free unit. The other thing I would check is that you haven't applied too much pressure with the extruder to deform the PLA as that can cause a plug as well. This is much more rare on the spring and bearing extruders. Then, consider printing faster so as to push the filament out quicker, thus not allowing as much of a molten PLA build up. Conversely, you could lower the temp you are printing at. Finally, consider active cooling.

Took your advice and sent support an email about my problems. Hopefully, they can help me get a print head that works as advertised without constant fiddling.

Another question: I'm using white PLA filament and the objects I'm printing out seem rather fragile. It feels like parts made of rice cakes. Is that normal? The crumble so easily, I don't know how they could be used in a real device. Maybe I'm using the wrong plastic. I just liked the bio-friendly aspect of PLA, but don't want to give up durability. Should I be printing with another type of filament?

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This all sounds as the nozzle or the hotend is somehow obstructed. That would lead to pressure building up that pushes the bowden tube back and out - and it will also lead to much too few material pushed out of the nozzle, making the whole print very fragile.

Is that PLA from Ultimaker that came with the machine? That one is usually _very_ reliable and unproblematic. But 3rd party PLA (especially very cheap one) tends to have impurities that quickly obstruct the hotend...

So check the nozzle/hotend if there is something (apart from PLA) that got in there.

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Is that PLA from Ultimaker that came with the machine? That one is usually _very_ reliable and unproblematic. But 3rd party PLA (especially very cheap one) tends to have impurities that quickly obstruct the hotend...

I can add a bit on that. Here on Ultimaker we test every new type of PLA we get. We already had a number of experimental rolls with different additives that we discarded because they clogged nozzles.

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PLA shouldn't be a problem. First, I would flip that comb (black F-shaped thing) around so that the f is covering that socket and holding the temp sensor into the board so that if you do get another plug and bowden pop it doesn't pull the sensor with it. Second, can you post a picture of your hotend? There can be some confusion in assembling the hotend on the v2 (new ones) and if incorrectly done it will lead to a blockage and plug almost every time. Third, have you gone through the first run wizard in Cura? That will get you close enough on your steps per e that you shouldn't have any problems. You can get some issues with that as the extruder is either under or over extruding which will lead to plugs from the material not getting forced out quickly enough and thus flowing upward into the PFTE/bowden junction or grinding of the filament followed by a plug (respectively). If you can upload a pic of your filament, that can aid in the diagnosis. Also, you should be able to slide the filament (with a clean cut end, not a mangled end from a previous print) through the bowden with ease. If you can't, measure your filament with some digital calipers. If they are 3 mm or less, measure the inside of the bowden, if you still can. The bowden should be close to 3.1 mm. Sander at UM is going to probably want those measurements if he's going to send you another bowden. Chin up! You'll get it working !

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PLA shouldn't be a problem. First, I would flip that comb (black F-shaped thing) around so that the f is covering that socket and holding the temp sensor into the board so that if you do get another plug and bowden pop it doesn't pull the sensor with it. Second, can you post a picture of your hotend? There can be some confusion in assembling the hotend on the v2 (new ones) and if incorrectly done it will lead to a blockage and plug almost every time. Third, have you gone through the first run wizard in Cura? That will get you close enough on your steps per e that you shouldn't have any problems. You can get some issues with that as the extruder is either under or over extruding which will lead to plugs from the material not getting forced out quickly enough and thus flowing upward into the PFTE/bowden junction or grinding of the filament followed by a plug (respectively). If you can upload a pic of your filament, that can aid in the diagnosis. Also, you should be able to slide the filament (with a clean cut end, not a mangled end from a previous print) through the bowden with ease. If you can't, measure your filament with some digital calipers. If they are 3 mm or less, measure the inside of the bowden, if you still can. The bowden should be close to 3.1 mm. Sander at UM is going to probably want those measurements if he's going to send you another bowden. Chin up! You'll get it working !

I'm using white PLA purchased with the machine from Ultimaker. I ran through all the steps in the Cura wizard. Everything checked out fine. Here is the hot tip photo:

untitled_24.thumb.jpg.b8560487fbdf1bf4a0875d6ecb2aaa4c.jpg

Based on what you're saying, I think my first couple Bowden pops (out of 50+ pops over the past week) and/or the Peek melting must have created some plugs in the feed path. That meltdown also melted a deep pit in my build platform, but I flipped it over to use the other side. My temporary fix for the Bowden was to put a screw through the wood and into the side of the tube. Here is a photo of that:

UM-forum-1.thumb.jpg.c72dc350e0bfb8d32d57b9e0d055f419.jpg

The Bowden doesn't move now, but it has created a new problem. The extruder is grinding the filament and unable to feed after a couple layers are printed. This again, supports your plugged feed path idea. If the Bowden isn't moving, then something else is preventing easy feed (it's not the screw, btw - double checked that it's not impeding the filament already). Also, there is massive leakage of brownish (burned?) plastic coming from around the brass/aluminum joint area. I figured it was because of the melted Peek but maybe that's another symptom of blockage? Would the leakage stop if I find the plugs?

Bottom line: I guess it's time for me to disassemble the print head to look for plugs.

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Yep, take that bad boy apart. You have massive leakage. Be sure to do so while the parts are all still hot, not just warm, but HOT to make sure that all that PLA that around your threads is liquefied enough to not snap the brass. Then, I'm betting things were not tight enough inside your hotend to provide a good seal. Your PEEK melting probably only exasperated this.

When you get everything apart, again, be careful to have plenty of heat, I would use a torch/lighter/heatgun to make sure you get everything completely cleaned up before trying to reassemble. I went through a heat, clean, heat, clean heat, clean process to get every bit of PLA I possible could out before trying to reassemble. Then, I would re-assemble it (again, use some heat) first on the bench before trying to assemble everything on the actual printhead because you are invariably going to have to heat it, screw it together, back it out, clean it, and repeat several times to get it to a point where it's not having any bits of PLA stuck in the threads and whatnot. When you are happy with it, then go ahead and reassemble it on the printhead. After you have reassembled it, I would heat and cool the hotend a couple times. After you have done that, heat it back up and carefully check to see if your assembly is still tight. Heat cycling it once or twice and checking "tightness" before you try to print should probably be in the Wiki for first assembly, but I would say definitely needs to be done if you are taking things apart that have had PLA in them. I would bet that's the source of your first leakage. Because your PEEK melted, you may need to put some Teflon tape in that section, but I would recommend NOT doing that unless it leaks. The tape just asks for an obstruction. With a V2, you shouldn't need any Teflon tape.

Did you check to see that you can easily slide the filament through the bowden, by the way? Not all the way through to the hot end, but just up to it? If you can, then we can eliminate the filament and bowden have too much friction for your feeder drive. If you can upload a picture of the filament showing the driven section and the ground section as well, that would be helpful!

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The Peek just crumbled apart. It was deformed so badly that it wouldn't come off the brass. I need to order some parts before I can proceed any further. Thanks for all of your help guys. It looks like this printer is on hold until I get the parts. I can't wait to join you among the happy ranks of fully functional Ultimaker owners.

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After removing the remaining pieces of the crumbled Peek, I noticed the brass had cracked badly inside the melted Peek. This was the source of the brownish plastic oozing out from the bottom edge of the Peek. I cleaned out the tip and aluminum block while they were hot and then tried to pull the thermocouple out of the block to set the metal parts aside. Of course, the heater had welded itself in place during the meltdown, so the wire came off and the heater is in the block permanently.

When I step back and look at this sequence of events, it just boggles my mind that this entire chain-reaction of printer self-destruction was started by something as simple as Bowden pops. The single pop that caused the meltdown created a seemingly unending string of problems for me. I got a reply from Ultimaker this morning. They told me to just buy the replacement parts and fix it. They seem to believe I'm retarded or something and that I caused all of this myself. My actions were all in reaction to a poorly-designed Bowden retention system. I mean seriously, a glorified plastic grommet and a little blue horseshoe is their retention system for a system which pushes solid filament through a tube?!? That's weak, at best. The forums have a bunch of posts about people having the same Bowden pop problem. Mine just escalated further than others'.

Anyway, I'm stuck waiting for a couple hundred dollars worth of parts to arrive so I can basically build a brand new print head and try again to make the Bowden stay put. Needless to say, I won't step away to take a phone call for 10 min during test prints this time around. Bowden pop = temp sensor pop = total meltdown. I learned that the hard way.

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For those who asked for pictures of my filament. This is what it looked like when I retracted it out of the Bowden tube to have a look.

3.thumb.jpg.86d5c41900d02b69defb5dec91ef2ec0.jpg

According to my digital caliper, the filament on the spool seems to hover around 2.86mm give or take 0.01mm. When I was trying to print, I had already adjusted this value in Cura. Unfortunately, I never got more than a few layers printed before the Bowden popped, until I finally screwed the Bowden in place. Of course, finally getting it to stop popping was long after the Peek/build surface/fan shroud/brass tube meltdown, so I could finally print more layers, but they were messed up by the massive leakage, so it was moot.

Anyway, the filament moves through the tube fairly easily, but with noticeable scratchiness/vibration. Once I pulled the filament back out of the tube, I could see that the feed mechanism is chewing up the filament a bit, which explains the vibration. The rim of the tube is catching on rough patches as the filament enters the tube. Once I get it working with all of the stock replacement parts, I'm going to print the parts to switch to a 4mm/6mm Teflon tube. Already picked up the tubing for it.

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You definitely have some issue with grinding the filament. That to me looks like it's facing an obstruction and trying to push through it, thus chewing bits and pieces, which will generate more friction in the bowden and create the plugs. We may need to take a look at your extruder settings if the problem persists after you reassemble.

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Just a quick update. I'm still waiting for the parts I ordered last week.

In the past few days I took the head completely apart and carefully checked the Wiki instructions again. I also examined each part carefully. I figured out what caused all the problems. The cause was that I followed the instructions perfectly. The instructions told me to use the top marked 8A. So, I did. When I finally forced the Bowden tube through the gray plastic with pliers (it was extremely difficult), I damaged the gray plastic part. This is because I followed the instructions and the instructions are wrong. I figured out yesterday that I was supposed to use the unmarked top piece which has a cone shaped hole for the gray plastic part to expand outward during insertion. The instructions told me to use the marked top and I did. The Wiki is also wrong about which direction to install the restraint for the temperature regulator wires. If the instructions showed the correct position, the plug wouldn’t have unplugged. So, the temperature wouldn’t have hit 460C+ and I wouldn't have melted my build platform, my Peek, and part of my fan shroud.

In addition, there are no instructions on building the PLA spool holder and no guidelines for the perfect settings for printing with Ultimaker's brand of PLA. I basically left my test prints set for 225C, which was the default in Cura. I've seen other printers advertise that 185C is good for their PLA. Anyone know what settings work best?

Having better instructions would probably solve 99% of the many problems people have listed on the forums.

Anyway, I guess it was my fault for following the Wiki V3 instructions exactly. Those instructions need to be updated. I won’t follow the instructions next time, since they are incorrect and incomplete. I understand how the printer is supposed to work, now. I'll be better off without the instructions.

I'll keep you posted after I get the parts and rebuild the printer. I'm guessing I won't have any issues this time around since I figured out where the instructions were wrong.

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My saga continues. There was a problem with me communicating my parts order. I originally asked for the long white wire that goes from the Arduino to the aluminum block. Not remembering the name, I accidentally later referred to it as the thermocouple, which was obviously incorrect. The parts arrived a couple days ago and the long white wire that goes to the Arduino wasn't in the order. Instead, there was a short thermocouple wire. Going to keep it as a spare. The other items were right, though. Since it's been over 2 weeks since I got the kit with nothing to show for it, and I will now have to wait another full week for parts, I emailed my annoyance. Then, I looked back at my emails and noticed my confusing description when I originally placed the order. So I emailed again to tell them it was my fault. I said I was sorry for the mix-up and just to send me the correct wire (heater wire) as soon as possible. I asked them how much money I should send via PayPal, so the order could get out the door. I'm guessing nobody answers emails on the weekend, because I haven't heard back on price since I sent the email on Friday. It's Sunday night.

This time difference is killing me. If I answer their email at 8AM my time, they're already gone for the day. When they get in, it's the middle of the night here. If they ask me a question, I don't get it until 8 am the next day, which means they're already gone again. If any prospective buyers are from the west coast U.S.A. timezone, be warned that your emails always take 24 hours minimum to get a reply. It works like this: Monday morning 8 am send email. Tuesday get an email back. Immediately send reply. Wednesday get email back. Send reply. Thursday get email back. If you send one Friday morning, you don't hear back until Monday, which really hurts. One email per day can get very old when troubleshooting. Speedy turn-around is just impossible unless you stay up until 2am to contact them.

Anyway, I went ahead and assembled the things I could and now I'm just waiting for them to ship me a heater wire, which probably won't happen until Tuesday, since I'll get the reply with the price on Monday morning and they'll already be gone for the day. *sigh* I already contacted Type A to buy one of their dual-extruder machines. Maybe I can make some parts with that one to get this Ultimaker working.

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You could print at 185C, but VERY slowly. The speed of the Ultimaker makes it need higher temperatures. Start out with 230, and if that works, drop down to 210. 210C is what we always use at Ultimaker HQ.

Thanks Daid.

Any chance you know the price on the heater cable/cartridge, so I can send the PayPal to get it shipped? Got up extra early this morning to check my email and still no reply.

Alternatively, do you know someplace in the U.S. where I can order it? (or any other parts for Ultimaker) This time difference is crazy frustrating.

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I understand the time difference is frustrating. But the heater cartridge is a custom part, so I do not think you could find an exact replacement in the US. It's not a difficult part, just a 40W 19V heater in a casing. But finding one with the proper dimensions could be a problem.

I don't deal with the money side of things (being R&D and all), so I do not know the costs. If you emailed support, they should mail you back today.

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Ok, just found some more Ultimaker web site strangeness. When I tell the Ultimaker Shop to list all parts and accessories, there is no heater cartridge/cable listed. When I Googled for another supplier, it listed an Ultimaker shop page for buying it!! So, I just ordered it using that page. I hope it's the right one, since it cost E45 to ship the E32 item. That's one more drawback of buying from the Netherlands. I've spent over $500 on shipping alone. *sigh*

The item I just ordered said 40W 18V. I hope that's the right one. I'm stumped why it doesn't show up in the shop.

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