Budaschnozzle + Wade's = Kinky?

I completed my build of a MendelMax 1.5 (parts from Techpaladin) and am running a Budaschnozzle v1.1 (w/1.75mm PTFE liner), 50mm nozzle with Marlin firmware. First off let me say that, when working, this thing prints fantastic. Now, on to the issue:

I have been printing with 1.75mm filament from Ultimachine at 185C @ 60mm/sec and am running into an issue where 30min. into a print the filament will jam. The jam occurs in a cavity between the extruder assembly and the hotend (see attached image). I initially thought it was the hotend that was clogged, causing the filament to back up into this cavity. After disassembling the hotend and finding nothing amiss (nozzle and PEEK were clear, no obvious jams), I double checked my firmware to make sure that the E-steps were correct (sure enough, 30mm of requested filament from the host software resulted in 29.8mm of filament driven through the hotend). Something else must be going on here. After clearing a jam mid print, I can re-feed the filament into the hotend and push it through easily. The only thing I can surmise after all of this is that heat is seeping up into the PTFE and causing the PLA to expand, adding friction and causing everything to jam up in the cavity. Has anyone else ever had this issue? Would a fan blowing on the heatsink help? I have tried several combinations of speed (30mm/sec. - 150mm/sec, 180C-195C) and always the same result, the grinding and kiniking of PLA between the extruder and hotend.

I have also noticed that PLA seems to be seeping out from the threads between the PEEK insulator and the threaded extension resulting in a puddle of nasty, molten PLA sitting on top of my heater block. Again, is this normal?

Thanks for the help!

My guess is that the filament gets too soft in the upper part of the hotend. Either try to print at a slightly lower temperature (if that's possible) or add a cooling fan aimed at the upper part of the hotend.

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regards,
Tom

You need to get rid of the cavity. It looks like the extruder block was designed for a different hot end that fitted internally. The feed path should be just a little bigger than the filament all the way down.

No leakage is not normal and usually complete failure follows soon afterwards.

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[www.hydraraptor.blogspot.com]

That's disappointing to hear. I've only been using the hotend for a combined total of 10hrs. I am able to disassemble down to just the heating block, threaded extension and PEEK insulator. Past that I cannot separate the PEEK from the threaded extension to try and reseat the connection and stem the flow of super-molten PLA. A conversation w/ Lulzbot suggested that this was merely a cosmetic issue and should be cleaned only if is was visually bothersome.

Quote

"The leaked PLA on the threaded extension above the heater block can stay unless you would like to clean it for aesthetic reasons."

Sounds like it might be otherwise. I've never abused the hotend (never been above 195C and/or 150mm/sec) so its disappointing to hear that imminent death is a possibility, especially for such an expensive hotend. Anyone else experiencing similar leaking issues?

I will have to try and mount a fan tonight and see how that impacts this issue. Thanks all!

I have never used a Budaschnozzle, but my own experience is that when there is a leak it means there is a gap somewhere and that usually causes a jam.

Also the leak usually does not stop, so it slowly flows over the heater block and starts to put brown bits on the object being built. If it doesn't continue to grow then perhaps you will get away with it.

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[www.hydraraptor.blogspot.com]

We have about 12 of these hotends and they are fantastic. Took one apart to check this out. There is a printed cylinder that should go in that space. Might want to grab the file from Aleph Objects website.

I installed a 40mm fan last night to blow across the heat sink in hopes that this will help keep the temps inside the hotend from causing the PLA to expand too much. I'll have to try adding one of those printed cylinders to help keep the filament straight. Guess this is one of those (many) learning moments where there is no documentation on needing this part on any of the tutorials I looked at while building / running the machine. Trial and error is fun and all, but I cant wait to get this thing up and running reliably. With a newborn in the house I get 1.5 - 2hrs a night to monkey with it before I'm too tired to think straight.

Atac572 - You say that you are running 12 or so of the Budaschnozzle, do you notice any leaking PLA between the PEEK insulator and the Heating block? I can definitely tell that it is actively leaking as the color changes depending on what filament I am using at the time. I can clean it well enough by running a cotton swab around the threads while up to temp, but it seems a little unnecessary.

We have a mix of this version and the older ones. Looking closer at the ones like yours the only thing I can think is that the nozzle isn't seating all the way up against the end of the threaded piece. Effectively creating a cavity between the end of it and the backside of the nozzle. If a cavity exists here the pressure pushes the plastic out through the threads.

I would take the nozzle off and then screw the heater block up a few turns so that you know the nozzle will bottom out before it contacts the heater block. Tighten the nozzle. Then run the heater block down till its touching the nozzle.

I hope that helps, like I said we have had no issues with these so I'm just thinking of the most likely cause.

This is probably a little late, but I also had the exact same problem. The budaschnozzle doesn't have sufficient cooling ability when used with a hot bed so its pretty much required to use a cooling fan somewhere around the nozzle with PLA. With ABS its fine without the fan. I bought a cheap small desk fan ($5) at a local store and placed it next to the printer, that seemed to work enough to keep the PLA from jamming, and my prints went up in quality.

Thats pretty much the same conclusion I came to. I added a 40mm fan on the x carriage and since then have had no problems jamming. Still have the leaking issue but cannot seem to separate the PEEK insulator from the threaded tube.

We have printed hundreds if not thousands of parts in PLA (Ultimachine's) and don't use a fan. If you are using a fan, your temp is probably too high. Make sure you are using thermistor #7 in your firmware so you are getting the correct temp readings.

I have been able to cure most of the issues concerning jamming with the addition of a ducted fan which blows on the Copper heatsink. The jamming issue typically arises if I am printing too slow with the fan turned off. I print with Ultimachine PLA at 185C (with thermistor #7 selected in firmware) and get absolutely amazing print quality so long as I am printing fast enough that heat does not creep up the filament and cause die-swell / jam. Some other culprits might be a insufficiently grippy hobbed bolt which cannot force the swollen filament through the extruder. I purchased a Trinity Labs micro extruder (http://store.mendelmax.com/trinitylabs-micro-extruder-gearhead-motor-and-options/) to replace the Wade's that I have been using.

If you continue to have issues with it jamming in the gap between the Wades and the hotend, you can do what Chowderhead(A member on this forum) did, design a cylinder with a hole in it that fits in the gap between the Wades & the Budhaschonzzle.

Just download the scad file and remove the hole. It's what I ended up doing after I had the same issue.

You could try http://www.thingiverse.com/thing:21412 - this is ment to go in the hole in the bottom of the extruder. I haven't actually used this so I don't know if it actually works as I didn't really experience the problems your having. I would also (as someone else did) suggest checking that you have the right thermister selected in the firmware. It may also be an idea to put some heatsink compound around the thermistor as mine didn't have any and I noticed that the temperature of the heat block would vary 5 to 8 degrees C around the set temperature. I put this down to the fact that the thermistor was probably not making very good contact with the heater block. My Budaschnozzle never leaked and I was able to completely dismantale it. If the PLA is leaking out the PEEK thread it sounds like the PTFE sleve is not butting up against the threaded extension tight enough. The PTFE goes through a hole in the top of the PEEK which centers it on the threaded extension.

I had a similar problem with my budaschnozzle 1.1 leaking and causing the pool of burnt PLA on top of the heater block. This didnt happen when I got the buddaschnozzle, only after I changed the tip from 0.5 to 0.35 did it start leaking...I obviously did something wrong when tightening the new tip.

I thought screwing it on until it became tight with the aluminum heater block was what should be sealing it. What should seal it is the tightness between the nozzle and the threaded rod, NOT the nozzle and the heater block. I solved the problem as described below, and now I have a gap between the heater block and the nozzle tip (results in less heat transfer, but I am still testing the seal to make sure everything is completely leak free before screwing it back down)

While the end is hot, try moving the heater block "up" the threads, so you can screw the nozzle on tighter. I did this by rotating the heat sink while holding the heater block with a pair of pliers. This had the effect of rotating all the hot parts except the heater block, resulting in the heater block climbing up the threaded rod. I could then tigheten the nozzle on about 1/4 turn more, which solved my leaking issues.

I just wish I had known that before scratching up the aluminum heater block while trying to tighten the nozzle end "extra tight" to solve the leaking.

My leaking was definitely not cosmetic, as it would start to drip down onto the prints after about an hours worth of printing if I didn't clean it.

As for the jamming, try adding a fan? I don't have a jamming issue with my Wades extruder assembly, but I have a fan mounted on my electronics board, and some of the wind from this fan leaks across the build platform and also would have a cooling effect on the nozzle.

Just a follow up, I took my budaschnozzle completely apart to clean it, and I found that although it looked like it was leaking down from the peek insulator to the heater block, the threads which were in the peek were completely clean (no leaked material in the threads above the peek). It appears as if the leak that I had was all in the nozzle not being fastened on tight enough, and it climbed the threads via capillary action so it "appeard" as if it was flowing downwards but it was actually flowing uphill from the tip.

Move your heater block up a bit on the threads and then tighten your nozzle tip. Do this while the nozzle is hot and the plastic is goopy.

Mitchese: Thanks for the tip! I surmised as much over the Holiday break when I disassembled the hot end and found the same thing. After cleaning all the threads I was able to seal up the nozzle super tight and have since stopped much of the leaking.

Chris_NZL: Printed this over the weekend and it fit great! Nice find!

If anyone from Lulzbot or AlephObjects is following this thread there is one suggestion I would like to make. Would it be possible to add a hex keyed end to the threaded tube or a flattened section of threaded tube that we can get purchase on to tighten the nozzle. It was fairly difficult for me to get the nozzle tight enough to prevent oozing as there isn't anything to use to provide counter pressure when tightening the nozzle. This is especially true when everything is too hot to hold with your bare hands. My two cents. Thanks everyone for your help.

--Edit-- Can we label this thread as "solved" for other people who might have / be having this issue?

Edited 1 time(s). Last edit at 07/05/2012 11:17AM by archistrong.

This is Seth from AlephObjects/Lulzbot,

We are certainly following this thread. We are continuing to improve the Budaschnozzle all the time and really appreciate all the feedback, tips and ideas you guys come up with.

Seth,

Glad to see AlephObjects taking an active roll in the community. Keep up the good work guys! Apart from the couple of hiccups with the Budaschnozzle early on, it has been producing amazingly high quality prints and is very reliable. I also love seeing your updates on Thingiverse and your willingness to share source files for the products that you develop and sell in your online store. Wish I still lived in Colorado (grew up outside Denver), would like to see your operation. Do you have a physical store location? If so, I will swing by the next time I'm out there.

We sell things out of our shop all the time.
You can feel free to come by and check things out if you make it to the area.

Keep up all the good feedback guys!

I got exactly the same pb when I try to print with a 0.25 nozzle and 0.1 layer. the 3mm pla get soft and get stuck in the entrance hole (even if I have no gap except the conical entrance, it's where the molten pla get in contact with the cooler part and get hard again getting stuck )

I also got leaks
I also got big difficulties trying to go back to 0.5 nozzle, the use of aluminum nozzle on a threaded aluminum part is against the habits as it get griped quite easily because it not anodised aluminum and brut aluminum on aluminum is not self lubrification.

the better solution could be to have the ptfe tubing going through the mounting plate to the inside of the threaded part with a machined step inside the threaded part to assure against the leak, to use brass threaded part or brass nozzle

and to give the advice to use a fan like that : [www.thingiverse.com] when printing with pla and slow extrusion (slow speed or very thin layer)

also a good idea could be to add a nut on the threaded part to block the rotation inside the peek and to give more strength to fit and unfit the nozzle.

an option for the use of the fan could be to add an another resistor to double the heating power and tu use the fan to cool the heat sink and the part, because with the fan the max temp of the hotend is on the low side

That's too bad, I found it a nice idea,