randyinla

Hey Jonny, do you have any photos of the underside of the circuit board? Curious how the plastic handles the heat of the soldering iron. Great idea, by the way! I was JUST thinking how expensive (and ugly) standard perf board is a few days ago.

I recently started getting perfect, non-warping ABS prints with my U2. I've been spreading a thin layer of Elmer's All Purpose Glue Stick, heating up my build plate to 105c (will start trying 110c), but the best thing (I believe) I've done is build an acrylic cover and added an acrylic door. The enclosure isn't air tight by any means, but it keeps enough of the heat in during the print. So much so that the PLA cable chain I printed before I built the enclosure melts a little bit with every ABS print! I use the Aquanet unscented hair spray for PLA with great success, but it wouldn't make ABS stick for me. I take the acrylic cover off when printing PLA.

I recently built an acrylic dome-like cover and acrylic hinged door to my U2 (no filter). The goal was a heated enclosure for printing ABS and it is working fantastically! Aside from the great, warp-free prints I am now enjoying, I noticed two things; 1) A lot less noise 2) A lot less smell. Are these nano particles only present when the filament(s) reach high temperature? ie.even though I don't have a filter, once the print cools down and I open the front door, are the nano particles now gone? Or are they collecting on the inside bottom of my U2? Seems if I added a filter with an exhaust fan of some sort, that would suck the warmth out of my heated enclosure, no?

Printed the black grenade part of the lightsaber standing up. That's just the pattern that printed. I've never had anything else display that kind of pattern, so I'm guessing it wasn't my machine? I kinda like it, actually

I will check the simple version out. I love the way the parts came out in the complex version, just wanted the tighter, more secure connection for that one section. Here's how it looks now. 2nd has bronzefill parts. I tried printing the heat sink out of flexible black PLA, but it had too much road rash on the outer surface. Couldn't get the material to print smooth enough, so just used black ABS instead. If you look closely, you'll see the switch is printed in transparent XT. I have a Hasbro Luke lightsaber and the bubble switch part is almost identical in size/shape! Excellent modeling, Valcrow!

I used the same stuff he used. He first tries with deck screws, then gets some tiny steel pins. I used the pins and the lemon bright soap stuff. I can try again and let it go for a few days and see if that helps. Oh, I also tried rubbing the model with brasso, which didn't seem to do anything at all.

I've been meaning to try my hand at editing the switch section so the pieces on either end of it interlock like the two top pieces do. I'm thinking the floating part inside that holds the two round switches in place could fill the area more and be solid with the female three-point connector on both ends, male connectors on the grenade and heat sink. Then the pin could go back to just being a pin that holds the outer clip in place and not the entire core of the hilt. LOVE the design and look/feel of it. Very happy it was one of the first things I printed.

I bought a large Thumbler tumbler because of that guy's videos, Nicolinux. Made a few parts of the light saber model out of bronzefill and let 'em tumble all night in water, steel pins and soap. They definitely came out shiny in some areas, but not nearly as light and bright as that guy's owl.

I have fallen in love with Architect's Stone! I think the neutral grayness goes with a multitude of other shades of white very well. I printed out iRobertl's cable chain parts for the build plate cable using this material and it blends into the inner U2 perfectly. However, since I've built an acrylic terrarium top for my U2 to print out ABS parts, I found it gets MUCH HOTTER inside than originally anticipated. My PLA-based Architect's Stone cable chain melts a little more every time I print ABS. :oops: The main part that screws into the back of the build plate gets the worst of the heat, pulling it directly off the Z plate. The smaller chain parts also get mushy just from the ambient temp in the enclosed print area. Does anyone know of any ABS anywhere that has a color close to Architect's Stone? It's a cool, off white... very light gray-ish. I already have a standard 'white' ABS (plain white from iMaker.com) print of the chain, but it looks a tad yellowish compared to the rest of the bright white innards of the U2. Thanks for any suggestions! -=Randy

Thanks, Daid! I ordered a few of those encoders to play around with for something else

Here is the thermistor part: http://www.newark.com/ist-innovative-sensor-technology/p0k1-0805-2p-b/sensor-pt100-0805-class-b-0-04/dp/24M9666?ost=1266934 I'm ordering one as a backup.

I received a new circuit board from fbrc8.com (thank you!) and can put away my button hack! Was (sort of) fun while it lasted, but am SO much happier with the encoder!!!

Not entirely true, from what I've read. The pitch and spacing of the fins has a lot to do with noise/air flow as much as speed. The bearings of the original small fan were extremely whiny, buzzing. The replacement I bought was made by Sunon, same as the original. It had a different model number, but the same CFM rating of 2.2. The difference between the noise of the original and the replacement is more than night and day. From what I've read in the forum, most people's rear fans are already quiet. Mine wasn't. Now it is.

I believe the tornadoes are the two fans on the side, not the back? I recently replaced my smaller fan behind the hotend and it was 2.2 CFM. I don't think I would replace the hotend fan with one that pushes more air. Does that fan get faster/slower at times? Or is it just on at a constant speed all the time? If constant and replacing with a fan with a higher CFM, it might cool it down too much? Here is the smaller hotend fan replacement from the same manufacturer. Model: MC25060V2-000U-A99 http://www.digikey.com/product-search/en?KeyWords=FAN%2025X6.9MM%205VDC%200.38W%202.2CFM&WT.z_header=search_go BTW, I replaced it because the original one was whining so loud, it drove me crazy. The replacement is whisper quiet at the same CFM.

You know, every time I've seen suggestions to use hairspray in the past, I imagine they meant to just spray it on the glass. I thought, "No WAY I'm spraying that stuff into the innards of my U2!" Imagine that gunking up my bearings and rods?! But now that you say to spray it onto a paper towel and act like you are cleaning the glass with it, that's different. I'll have to give it a try. I don't see myself keeping acetone around for making the slurry. The glue stick works fine with ABS for me with my covered chamber. But using a wipe-on hairspray for PLA sounds like it might be pretty cool. Not only easier to apply/remove than the blue tape, but much faster and no pattern on the bottom of my prints!

I have yet to have any PLA successfully stick to heated glass or heated glass with glue stick. My ABS sticks perfectly to the heated bed with glue. Blue tape is the only thing I've used that the PLA sticks to. My corners do not curl up one bit. That is why I use the blue tape. It's a bit of a pain that the blue fibers have to be scrubbed off and a little blue tint remains, but I'll take that over a warped print any day.

I had replied to another thread about my successful re-aligning. Didn't notice the question here until just now. I loosened all the screws around the top/bottom of the U2 box, just enough to force the cube to be more square against my counter top. After re-tightening the screws, getting rid of the 1mm gap under the front right foot, I then loosened the 8 screws around the linear bearings on the z-stage and leveled the bed against the bottom of the U2, like the manual says. Once I had it all back together, I went through the leveling routine and all of my first layers are MUCH better than they used to be. I was able to print out a propeller protector for a quad copter that had failed 3 times in the past. It stretches from the far back left up to the very front right and the first layer's thickness/width looked identical all around. Very happy with the results.

Maybe attach some foam rubber to the backside of your dome? Since it's so small of an area, if sound hits that plastic from the back, it could be resonating the entire dome, which then directs the sound down into the mic because of its shape. Maybe 1/2" to 1" thick might deaden anything from that side. If that does have an effect, then maybe printing your reflector in something softer, like soft pla, would also work better? If it does, then try making the dome thicker, say 1/4"~1/2" with maybe 25% infill. A solid object will pass sound better than one with an air cavity.

Success! I was reading another thread and learned that different valued thermistors were sometimes used. I connected a potentiometer to the board to hopefully find the proper range for my machine and it worked! 120ohm registered between 42c~43c and 138ohm as 110c. I soldered in a 120ohm and was able to print out a small part in ABS. Went into the tune menu during the print and alternated the desired temp between 40~45 to turn the bed off/on. Was purely guessing as to the actual temp but will try my Fluke meter's temp probe tomorrow to get a better sense of actual temp. I'm sure support will get me sorted out soon, but being able to print in the interim is a welcome relief.

Thank you for your information, gr5! My heated bed temp sensor died and I am awaiting a resolution from support. In another thread, someone mentioned soldering in a 220ohm resistor and that got the machine to work again, but it didn't work for me. I figured something more serious was wrong. After finding out there are different valued thermistors used, I decided to connect a potentiometer to the bed and see if I could find a range that worked. Jackpot! a 120ohm resistor registers as 42c~43c and 138ohm as around 110c. I put a 120ohm in and printed up a small 8 minute object in ABS. Went into the tune menu during printing and just kind of guestimated turning the heat on/off by alternating the desired temp between 40~45. Will attach my Fluke's temp probe tomorrow to hopefully get closer approximation of the temp of the bed. I hope Ultimaker either sends me another thermistor for my U2 (or tells me the value I should have so I can buy a few from Digikey) or another heated build plate soon... but being able to print again is awesome!! Thanks again!

Would be nice to use M3 standoffs so the motor always stays attached, then the feeder could be removed independently. But then the feeder would sit further away from the back panel and not align with the knobbed wheel anymore. Could countersink the standoffs... but not sure I want to hack on the back panel like that.

Meh. Didn't work for me. I soldered a 220ohm across the SMD part and nothing. Then removed the part and put the 220ohm in its place. Still nothing. Error - Stopped. Oh well. I have a few other things I can work on in the mean time

Well, a quick googling revealed that the melting point for electronic solder is typically much higher than 100c. I doubt it melted due to the heat of the plate itself. Good idea putting the resistors in there so you can at least print PLA! I might research that a little bit. Maybe use my Fluke to measure the actual temp of the bed too. It would be nice if there was a small LED on the back of the heated plate to know when the power was being applied to it. Hope you get your replacement fast!

My heated bed sensor for my U2 finally died just as well!! It's been acting up for about 10 days now. Thorvinus, was yours for an U1 or U2? Where did you order a new heated bed? I went through the exact same steps you did, short of running new wires. I noticed the ends of the wires that were screwed down to the bed's connection block were soldered/tinned. Bad idea! After years of wiring up recording studios, I can tell you first hand that you are never supposed to tin the ends of wire used in screw blocks. Ever. The solder doesn't compress under the screw and you end up with loose connections that can arc or become intermittent at best. I clipped off the soldered ends, stripped back the wire and re-attached. I then noticed through magnifying glasses that the four pads of the connector block were moving slightly in place. Cold solder joints! So I de-soldered, cleaned, re-soldered, but they just would not take the solder. So I took the connector block all the way off and soldered the wires directly to the pads on the heated plate. Beeped it out to make sure things were cleanly connected and when I rebooted, I had the same thing as you; The temp would go up/down if I wiggled the wire or tapped on the back of the heated bed. Something is just not right with this design. That was about 10 days ago and I have been printing happily since then. It seemed relatively stable as long as I didn't touch the cabling or tap on the build plate. Today, I printed a 3-hour ABS part with a cardboard box covering the U2. I let the part cool down on its own, about 1/2 hour, then took it off the build plate with ease. No warping due to the door on the front and the cardboard box on top. About 5 min after I had the part in my hands, not even touching the U2, the display changed to, "Error - Stopped, Temp bed sensor, contact support." I did all the usual things, tapping, wriggling of cabling... nothing worked. I then took out the main circuit board underneath the U2 for the first time ever to see if that end of the cable was loose. The connector beeped out perfectly back to the white SMD part on the heated plate, not a loose solder joint or short. Just for completeness, I checked the wires that go to screw block on the main circuit board and sure enough, the green wires for the extruder head heating element were also tinned (but not the other two white wires...strange). Clipped the green ones and re-screwed in place. So now everything is back together and I have a dead machine. Is there any way to reset everything while turning it on? It might start working again. I assume you can run the U2 without a heated bed, no? The heating element and sensor are such rudimentary parts/connections, it's hard to imagine so much trouble! Should be able to totally disconnect it and have the U2 still start up. It would be nice to know if the little white SMD part has blown or if the main circuitry is hosed. I've been running the heated bed around 105 ~ 110 for ABS. Combine that with the heated chamber effect of a front door and cardboard box on top... could it be too hot for the sensor? One last thought I have that could possibly contribute to this failed sensor state is that I broke my encoder on the front circuit board around the same time the heated bed sensor started failing. (yes, user error. Yes, another one is in the mail) I have a new one coming in the mail, but have the front circuit board detached from the back of the front panel and sitting on the desk in front of the printer. I have connected buttons to the circuit board so I can still control the printer. Could this circuit board be missing a ground connection via being screwed into the back of the panel? Both sides of the white panel material has thin metal sheets that the screws must come in contact with. Could that be throwing off the sensor circuits for the whole box? I suppose I could try connecting the standoffs of that circuit board to the standoffs of the main one and find out for myself. Guess I'll open a ticket for this heat sensor and see what happens. Crossing fingers...

If the build platform gets a little wobbly when it's larger, how about a matching worm gear attached to the front side that is directly linked to the original one in the back? Or in keeping with the three-point alignment, add a Z worm gear to the front left and right corners, again, linked to the back one? As for assuming faster printing has to occur for bigger builds, I don't agree with that. I am perfectly fine with the speed of the U2 as it is and wouldn't expect it to be faster just because I am printing larger things. It's my decision to print a larger object, I'm fine with the speed. I rarely ever print faster than 50mm per sec so I'm kinda used to it.