madoverlord

I just tried this out, and it seems to work very well. I just went to the HW store and had them cut me a rectangle that fits on top of my acrylic build plate (going to the edges left/right, but not top/bottom so it does not interfere with the leveling holes. You can attach the glass to the build plate with ordinary binder clips, and have multiple plates and swap them in 20 seconds. I accidentally bought the other type of wood glue (Aliphatic Resin Emulsion) but it seems to work well. You will probably need to readjust your z-limit switch position, of course. There may be some borderline cases where you now need to use brim when using glass+glue, because the adhesion properties are a bit different from tape. tl/dr: looks like a great $5 upgrade!

Confirmed... Even with preferences set to English you get German, and after a relaunch with prefs set to English you can't get the Prefs window to come up again. On initial launch, after going through the setup in german, if you open preferences you find it says it is set to english. If you change it to Dutch you get Dutch on restart, but cannot access preferences at that point. Also, to exit the app you need to force-quit.

I'm doing one more cast to refine my instructions (hoping I can reduce the delamination issue), and absent any disasters the files will go up on thingiverse middle of the week.

Here are https://www.dropbox.com/sh/gwvrk66fgntoe9e/VQS-8oIHaB#/ of the injection-mold variant of the booty. I used a higher-temp (750F max) silicone, and got a fair amount of delamination of the mold surfaces. This may be because this type of silicone releases acetic acid during the cure, or because I cooked the mold in a mason-jar inside a rice cooker. I'll do an experiment to see if I can improve on that. On the plus side, I got a complete casting that literally fits like a glove. Side note: you can make plastic parts close to the hot end more heat-resistant if you stick on some aluminum foil tape. It reflects some of the heat and rapidly conducts some of it away from the heat focus.

I wonder if the silicone hot-end booty that I've been working on (lastest version, injection-molded, is in the dishwasher right now) would let you get closer to the hot end with a PLA duct. Or perhaps a couple of these with printed mounts that put their outlets close to the hot end: http://www.amazon.com/Brushless-Blower-40x40x20mm-Sleeve-bearing-Skywalking/dp/B00BKDV7JO

One rough way to guesstimate it is to feel the relative pressure coming out of the end of the hose vs. what's backing out of the fan itself. An Adda AD2012LB-K70 20mm fan generates 0.6CFM unconstricted. and a AD0312HB-D50 30MM x 15MM (pretty chunky) fan gives 4.2, and an AD0212LX-K50-LF 25MM gives about 1.8. Given the constraints on the stock hot end, you could only mount 3 fans on it, of up to 40mm size. Your big issue is going to be mass. The bigger fans are very heavy. But maybe 3 of the 30mm fans blowing in a triangle?

PS: foehnsturm, have you posted your design files for your fan setup anywhere? I would certainly like to take a look and experiment with them.

My injection mold had a few problems. A couple of the bolts interfered with the insertion of the silicone nozzle (which did work) which meant there were some leaks, and I need some more vent holes (and I'm going to thread them this time so I can use small bolts to seal them). On the bright side, the silicone was definitely flowing through the mold. Anyone got any tips before I print up another mold? WRT cooling fan design, it occurs to me that assuming you have good general area cooling and have minimized the heat transfer from the hot end -- and foehnsturm seems to be on the right track in this regard -- the real gains are going to be in making the slicer more aware of the physics. In the meantime, there may be a bit of a win by using more of the air for general area cooling.

The entire top (it's made out of two-subparts) of the current mold is open, I was just spreading silicone into the bottom part, adding the insert and screwing it down, adding more silicone to the edges and the top parts and clamping them in place, and then just scraping off the excess. I am currently printing a completely enclosed injection mold. When finished, it will have an injection port that is threaded 7/16NF20 to fit the tube of silicone, and several small 1mm exit vent holes on the diagonally opposite faces. Hopefully this will be enough to avoid trapped air bubbles. I also printed a toothpaste key to use as an injection device. I'll do the injection test tomorrow morning so it will probably be Wednesday before I can report results.

Did another pass at the mold, it's getting close to publishable. This version (https://www.dropbox.com/sh/ou1z52iwtq4hbtl/XhhmSoJJEN) is a boot that slides around the hot end and wires. Noticed that the nozzle of the tube containing the silicone appears to be threaded 7/16NF20; if so I should be able to make an injection mold version, screw in the tube, and fill the mold that way. Might improve the surface quality a bit, and eliminate mold lines and flash. Comments / suggestions?

I have updated the gallery in my previous post with some pictures of my v2 shield, which more completely covers the hot end and the wiring. I need to make some updates to the design (for example, the tunnel for the wires is too small), but it appears to be an improvement. Things I've learned: You need to completely clean the inside of the shield and remove all traces of the vaseline, otherwise it will burn and cake on your hot end. The cornstarch trick for curing works. Go easy on it, it works really well. I'd suggest maybe 10-20% cornstarch mixed in. Tiewraps become brittle when kept warm. The shield made only a minor improvement in the quality of supported overhangs using the stock fan. Those big triangular paperclip things make excellent clamps.

OK, I cooked my silicone shield for 30 hours in the rice cooker and it came out fine. https://www.dropbox.com/sh/ou1z52iwtq4hbtl/XhhmSoJJEN. Interestingly, I got a bit of delamination on the mold, but not on the z-axis layers. Flakes of the surfaces in direct contact with the silicone detached (but were easily removed). One thing I did do is dip the mold in water after lubing it up with vaseline, in the hopes this would speed the cure. I cut a rectangle out of the top of the shield so that the top edges overlapped the top of the hot-end, then punched holes for the heater and thermocouple wires, and added a slit up to the top so that the shield could be wrapped around the hot-end. I also had to chop off the bottom of the nozzle part to get adequate clearance. After putting the shield in place I added a tie-wrap for extra security. Temperature measurements (sorry for the mixed units) using the stock fan and duct at speed 255 with Z=0, using a crappy meat thermometer. Hot End Off: 78F Hot End On, No Shield: 92F Hot End On @ 210C, Shield: 80F (!) I'm currently doing an overhang print test to see if the shield actually makes a significant difference.

TIL, excellent bit of info. I'll have to add this to my evil bag of tricks.

Sugru is only good to +180c, and likes to bond to metals and some plastics, including ABS.

Just an update of my own. I've https://www.dropbox.com/sc/ilt34t2thwoqfxh/HuBbezJX_Y for creating silicone hotend sheathes and have a test sample curing. One issue with HTV silicones is that they cure by exposure to atmospheric moisture, so it may take a while for the part to cure given all the internal surfaces -- patience is a bitch. I cooked it overnight in a rice cooker set to warm inside a jar with some water in it to provide humidity, but I think I'm going to let it go another 24 hours before I crack it open. Worst case I'll have to get some of the 2-part mold-making silicone that uses a catalyst, or perhaps http://www.tapplastics.com/product/mold_making_materials/mold_making_supplies/silicone_putty/563.

Why not make an oversized shell (2-part), fill it with some of the silicone, and use the actual hot end to cast the inner surface of the silicone. Then unbolt and remove the shell, do a little trimming, and you should have something that fits like a glove.

Can you give more details about the silicon(e?) jacket?

I agree it is a very complex issue, and the design of the UM hotend does not make it easy to come up with good shroud solutions, because the heat block really gets in the way. One thing I have played with but need to work on some more is isolating the hot end from the cooling airflow, because the last thing you want is air passing the hot-end, heating up, and then flowing over the part -- it defeats the purpose. I have tried several solutions but I think perhaps the most promising one is a box that fits around the hot end with a fan that sucks air into the box via the nozzle area, thus blowing the hot air up and away from the part. Then we might be able to go with some fans or ducts that are attached to the UM frame, which would have the nice side-effect of slightly reducing the hotend mass.

Playing around with cooling fan arrangements has been sort of a mini-hobby for me, but while I've come up with some interesting and pretty designs that move a lot of air, the results are not significantly better than the stock fan. Thus, I am wondering if I am perhaps going at it all wrong. So, back to basics, and a question: What is the role of the cooling airflow? Is it important to cool the filament right as it comes out of the nozzle, or is it more important to cool the entire layer over a longer period of time?

So after reading the http://www.protoparadigm.com/blog/2013/06/vapor-smoothing-and-polishing-pla-with-tetrahydrofuran-thf/ about smoothing PLA with http://en.wikipedia.org/wiki/Thf, I got some of the solvent and started playing. It goes without saying that this stuff, like acetone, is nasty and should only be messed with outdoors, with a respirator, googles, and nitrile gloves on. Anyway, I built a simple vapor smoother but I was not particularly happy with the results. Also it can form explosive peroxides if you let it dry out, and that's always a risk with vaporizing the stuff. I tried the el-cheapo cold vapor method (solvent in the bottom of a jar, nuts and bolts to form a platform that keeps the part out of the solvent, no heat) but my initial results were not promising. By the time you get significant smoothing, the parts start to crack. There may be a sweet spot in timing but I flashed on a different idea. This was inspired in part by a that bathes the part in a flow of solvent, which struck me as very complicated. But I put it together with some previous experiments I'd done in mechanical smoothing, and came up with this system. Fill a small jar about 1/3 full of THF. Insert part and seal lid (I made a gasket out of a sacrificial nitrile glove). Use a rock-tumbler to ensure an even coating. Here's https://www.dropbox.com/s/q5vkfa2ehv0pcmj/CIMG3121.jpg and https://www.dropbox.com/s/duly97d4fwuvrxo/CIMG3127.jpg pics of my first attempt, which was 5 minutes of agitation of a broken scrap part. Let me know what you think and what suggestions for improvements you might have. Update: here's what the https://www.dropbox.com/s/uwincyw1dy48ulm/CIMG3130.jpg after another 5 minutes in the chemical jacuzzi...

I've been doing some design exercises to teach myself Viacad, and one of the things I've come up with is a cooling shroud for the X, Y and Extruder steppers. One size fits all, it just slides on with an optional tension lock-bolt. It accepts 40mm fans -- I am running 1 24v and 2 12v fans in series-parallel off the 19v LED output. With some tiny quiet fans sucking air out of the shrouds, my steppers have gone from almost too hot to touch to body-temperature or a little higher. Hope it helps, and if you have suggestions for improvements, let me know. http://www.thingiverse.com/thing:139882

I've gotten myself most of the way up the learning cliff with Viacad. It's got some rough edges to be sure (I ran into some anomalies when doing fairly extreme operations like splitting a solid with another solid), but at <$100 the bang-for-buck is clearly there if you are building parts. I've been playing with replacement fan ducts as a way to learn the program, here's a recent example... https://www.dropbox.com/s/r6uk0vg98h2uz5t/40mm%20Front%20Duct2-v32.jpg

I'd like to know where to get decent 6" tape. In my experience, only the Scotch-brand blue tape is worth a damn, every other brand I've tried has stuck to the parts like glue. And the widest I can find locally is 2".

As I was replacing the painter's tape on my bed for the 8th time today (I get great adhesion, what can I say?), it occurred to me that it would be nice if Cura was aware of the tape boundaries and tried to place objects on a minimum number of strips. ie: you could enter tape width and offset of the second strip from the front (because the first one is going to be a partial). Even something as simple as just displaying the strips in the UI so you could drag the objects would be very nice.

Just a followup. After some months of flawless operation I finally got another clog. I tried the usual things -- heating, candling, THF, but couldn't get whatever it was that was blocking the nozzle out of the tip. After trying to poke stuff free with a thin strand of wire like last time (a royal pain in the ass), I decided to use my head. I went to McMaster.com (probably the best place in the US for getting parts and tools online) and got a selection of very, very tiny drill bits.. #80, #79 and .0150 (the Ultimaker nozzle hole is .0157 IIRC). They are about $3.00 each. I clamped the nozzle to a soldering iron tip with a binder clamp, let it heat up, and then, holding them with needlenose pliers, gently pushed the drill bits into the nozzle (without rotating them, as I did not want to damage the nozzle hole) and moved them up and down a few times, first the #80 and then the .0150. After letting the nozzle cool, I blew some air through it using my Mk.1 compressor (lungs!), reinstalled it, and it prints fine (so far, cross fingers)