nick-foley

PLA I use 65deg and blue painters tape. Sticks great, rarely need to use a brim. ABS I tried 110 and blue painters tape, seemed to work ok, but only printed a few times.

Bummer, wrecked my fair share of stepper drivers for sure. The fact that they blow instantly if you install them backwards should definitely be screened on the board... or... even better... the standard for a stepper driver should be an asymmetrical connector. Anyway, seems like you're in the US... get your replacements from Pololu. Shipping is quick and the Black or Purple versions are both significant upgrades since they don't need fragile heatsinks. Purple ones are quieter too, but you have to mod your firmware to double your steps per mm.

Hahah, was cursing the forum yesterday for the same reason - abs is too short (or too common?) of a string for the forum search to use it. So searching for ABS related pages is a real pain. Pretty dumb/unfortunate. Anyway, yes, you can do it. Brim and Raft both work fairly well, the crux of the operation is getting the first layer smeared aggressively right on to the acrylic. It should also be very very hot... 260+? I've done it with a dozen or so medium-to-small parts and the results are ok. Honestly though, ABS is sort of a pain to get right, and even though I now have a HBP it is proving difficult to get the right balance of low fan for good layer adhesion vs. some cooling for good overhangs. If you need the thermal performance, ABS may be worthwhile, but my feeling now is that if you want ABS parts that are actually stronger than PLA, you probably need some sort of heated chamber.

Steps per mm will be double whatever you have in the firmware already, since the resolution is being doubled from 1/16 to 1/32. This means 2*70-something-ish for a stock ultimaker (forget the value since it's long) or 2*80 if you've upgraded your Ultimaker to GT2 belts. Regarding the stuttering issue - I haven't seen any issues since shifting away from the RC7 beta of Cura. I think it was an issue with that beta, since my printer with normal stepper drivers was also having the stuttering issue with files coming from that version of Cura.

Yeah, getting the exact same results here, 14.03 is unusable. Posted about it in another thread already, but will actually take a photo of a comparison I did the other day. 14.03, whether USB or via Ulticontroller, slows down drastically during curved sections and causes massive overextrusion there. The same files print fine using 14.01, USB or Ulti.

My understanding is that stepper motor temp isn't very representative of the energy it's consuming while printing in a traditional M=AV sort of way, but more of the amount of current being used as holding force in order to make sure it isn't skipping steps when trying to move at all. Which is to say I suspect your motor is just hotter because the stepper driver potentiometer for your X axis is simply tuned for a higher current than the one for the Y axis. Any uneven amount of friction in X vs Y is usually pretty easily diagnosed by moving the printhead by hand when the machine is off. Oiling axes works well but it's also short lived solution in my experience - whether you use great or mediocre lubricants, it eventually ends up as sticky gunk on your axes after a few months, either because of collecting dust or because of hardening itself. I've now washed everything in acetone and live with the slightly higher but rarely problematic friction of dry axes and bushings, just letting the bronze and polished steel do their thing. Lubrication can be a good diagnostic tool for isolating the source of gantry resistance, though - lubricate one motion point at a time until you find the problem spot.

Whoa, sorry everyone. After more testing, it's clear that this isn't a hardware issue or a firmware issue at all, it's an issue with the latest Cura release candidate. That's what I get for using the latest beta (14.03 RC7). Problem disappears completely when printing with 14.01. Will do a little more testing and post a photo comparing different printing methods and Cura versions.

Cool. Where did you get them? Do they seem to be any better?

Hey everyone - After a few of my stepper drivers started acting up (and the flimsy heatsinks were knocked off), I decided to upgrade all of my drivers to something that could handle more current without overheating. I'd previously swapped to the Pololu (Purple) DRV8825 drivers, since they can handle higher currents and run quieter. It seemed that the only significant difference when installed on a UM1 would be that they would be using 1/32nd microstepping instead of 1/16th, and I would have to update my firmware to reflect that. After installing them, tuning them to provide a good amount of torque, and doubling my steps per mm in the firmware, it seemed like things were going well - noise was definitely lower and movements seemed to be accurate. Once I started printing, however, it became apparent that something is wrong. Straight sections print extremely well - whether diagonal or orthogonal. Curved sections, however, are slow and jagged - the machine stutters as it goes through them, causing overextrusion in those areas and very uneven output. Can anyone with more electronics experience than me offer some suggestions as to what could be going on? I'm pretty confident it isn't velocity/acceleration/jerk settings in the firmware, since I've been playing around with those values and matching them to a known-good machine that does not have this problem (but has the Pololu Black Drivers). I have a few other suspicions, but I'm not confident enough in PCB design to say that there isn't something obvious and dumb I'm missing about the compatibility of these stepper drivers and the UM1 electronics. There is a helpful list on the Pololu DRV8825 page (linked above) which describes the differences, but without a better understanding of the UM1 electronics, I have a hard time knowing which are meaningful. Thanks for any help anyone can provide. Figuring these out would be a sweet upgrade for the community, because who doesn't want a quieter, more reliable machine for $30 in parts??

Depends a lot on your scale, I wouldn't try to print wires thinner than 1.5mm or so, and you'd have to expect a learning curve to get your print settings really dialed in in order to get usably good results at jewelry scale. I've printed nice and delicate bracelets but rings would probably be pushing it. Getting a smaller nozzle may completely change this though... haven't tried it. If I were aiming to mostly print Jewelry I would probably get a Form1 or move upstream a bit to get a wax printer.

Noctua 40mm are silent, powerful and come with a 2 to 3 pin adapter. Not exactly cheap ($15 US) compared to other fans this size but worth it.

I designed a fan shroud with a hook built into it, added a loop to the top of a print, and wrote a test piece of gcode which I ran after a print to hook the loop and pull the print off the bed. It worked, and with more tweaking could have been very effective, but I ultimately decided that it was a better use of my time to use one of the 5-axis arms I was born with to pull prints instead. Having printed a lot more since then, I now know that large prints frequently stick to the build platform extremely well... so well that the printer could easily be damaged pulling the part from the build platform if you don't do it carefully. I think a build platform with a hopper of ejectable build platforms might be a better direction, or maybe something like the original TOM. They bring their own problems, though, I'm sure...

Wow, mysterious. I always assumed that the sound wasn't implemented. I guess my Ulticontroller had a broken piezo right out of the box! Luckily I prefer a silent printer.

Bummer! I'd been wondering if that was a possibility, but have yet to see it on any of my printheads. That's an indicator that you could be printing hotter if you want to get the full strength of the material across the build lines.

Looking way better... it seems like there is a very slight amount of overextrusion happening. I generally try to do all of my debugging prints in non-transparent filament because of how much more difficult it is to identify problems with clear filament...

Hmm. I've also shortened my bowden tube by 5cm or so, since less of it is locked up inside this printhead compared to stock. Could be making a difference...

Merlin prints look excellent. I wonder what I'm doing differently to have such drastically lower stringing on the UBIS... maybe temperature?

Sure - it's just some stock JST connectors on a circuit board we're using in an electronics assembly. STL is here: https://www.dropbox.com/s/oizet1nofi5xx6d/Inner%20Housing%20v1.8%20-%20PCB.STL You need to drop it 1mm or so into the bed or it tries to print the PCB floating in thin air.

This looks like some overextrusion + too high of temperature. I haven't tried the torture test, but I was printing some mockup electronics connectors that are definitely a challenging print for stringing and retraction: As a scale reference, those screws are T7's and the columns are just under 1mm in diameter. There are 40ish of them. Came off the printer looking like this. Ultimachine Green PLA.

I'll try to find a good piece of gcode but most of my prints are only on my SD card, far away from me right now. I've never tried PHA/PLA, but once I upped the retraction settings, stringing with PLA was completely eliminated... Will try to post something more specific than that tomorrow.

I'm going to assume that you have updated firmware installed, due to the custom hotend, but just want to make sure that you have the retraction speed fix. If so, maybe try the retraction settings I posted above? Is that Printbl Emerald filament or someting else? What temps are you using? I'm usually around 205C / 0.1mm / 50mm/s with this UBIS. If you think it might be a cooling problem, printing two copies at once is usually a good way to alleviate any print issues while you test that as a cause. Sorry for grilling you with questions. I'm away from my printers now, so I can't give exact settings, but some of the last prints I did before I left were that pyramid, and they came out almost breathtakingly perfect. Zero strings, blobs, or curling, and an almost needle-sharp point at the top with no bulging from heat....

Sounds like you're getting uneven extrusion, maybe from a feeder mechanism that isn't working as smoothly as it should. Are things smooth when you handcrank some filament through the hotend? And to the previous poster who made the fan mount of the hotend, please , of course share your mods with everyone else. Also worth noting is that with the UBIS you can increase your retraction settings to get perfect, string free prints at all settings... I use 35mm/s and 4.5mm (with updated firmware) and get very clean results.

Looks great!

Having installed 3 UBIS hotends now, my experience is that the thermistor reports temps around 20° lower than what the filament is actually seeing. Probably due to an improper thermistor table. Isn't a problem in practice though... the "temps" we print with are really just learned abstractions anyway.

Post some prints? Looks good.