chopmeister

And one more question, suppose I don't get this ATX PSU to work, what should I buy? Is something like this appropriate?

Oh. I guess I should have known that earlier. I found a ceramic 10W resistor I think it was around 50 Ohm and hooked that up to the 5V rail, and another smaller one on the 3.3 Rail. Connected the green wire to the ground to start the PSU, and repeated the procedure from above. The fan twitched for a milisec and that was that. Now whatever I try to do with the PSU (like connect peltiers and fans like I used to do before) the PSU fan just twitches and nothing happens, I can't get any voltage readout on the wires. I'm presuming I accidentally burned something in the PSU in my previous attempt?

Hi guys, I just got a Prusa MK2 heated bed. I've got an quality ATX PSU I'd like to use from a PC I don't use anymore. It is rated for 350W and 12V/16A. I suppose that should be enough. I wired the thing according to the ultimaker Wiki. I first uploaded Marlin from marlin-build. I tested the thermistor and it works. So I continued to wire stuff up. Now, I connected one side of the PCB to the 12V (yellow) wire of the PSU, and the other side of the PCB to heated bed pin 2, as instructed. I soldered the PSU ground to the UM ground on the UM power supply jack (on the side pin, towards the power switch). I turn on the printer, connect the USB and turn on the ATX PSU. Everything works, and the ATX fan spins. I also get a temp readout in printrun. But as soon as I set a temperature for the bed, the ATX PSU switches off. What to check, and what to do? I know there's electronic experts here (I'm definitely not one of them) so any help would be much appreciated, I'd like to get this thing running as soon as possible. Thanks!

Hehehe, no problem. I've already done the models, and I'm uploading them to the thingiverse page right now. Just print it like everything else 0.2 layers, whatever infill. First push the spacer bit into the bearing hole so that the opening is toward the inside of the extruder. It will slide in relatively easy. Then hold the spacer in place and push the bearing inside. That will be a bit harder to do but it will hold it in place. The rest is the same as with the normal setup, except replace the standard clip with the one provided. You can print another spacer if you don't want to use the 608ZZ bearing on the gear side, just install it the other way around so that the bearing points outwards, and you're set. Let me know if there's anything else, and of course, some pics of the final setup would be nice.

3mm you say? Hmmm... that changes things, I had absolutely no clue that they changed that too. Mine are 5mm. Well, It's basically the same deal I suppose only the spacer has to be wider and that's it. I'll print and test the bearing spacer now and upload it on the 'verse. Just tell me how deep is the groove for the V3 bolt clip, so I can adjust that too.

I'm sad to say it seems that it won't work as is. I had no clue they moved the knurled part. On my V2 bolt it's almost 8mm from the bolt head, and here it's 5mm from the clip. The sides of the H3 are 7mm thick to accommodate the 608ZZ bearings, so that would offset the 'good' part of the knurled pattern away from the filament path. But! Where there's a will there's a way. Using a smaller bearing from the stock extruder would get you just enough space to bring that nasty knurling where it belongs. See attached diagram and pics. The V3 would retain it's easy-to-remove function with the new clip. The only thing that matters here is that the bearing spacer is a really tight fit with the 688 bearing, and it should work. I know the number of parts on this beast is already through the roof, hehe, but these are just 2 very small additions. Now since I don't own a V3 bolt, what I can test is the bearing spacer, so that it fits nicely. What I can't do is test how the new clip would work. So if you want to give it a shot, that'd be great.

Hi! Thanks for the kind words. I know I'm not "anybody else", hehe, but I'm here to help. If you can measure the V3 bolt and draw me a sketch with the dimensions, how long it is, the length of the thread and all that, I can tell you if it works, but I assume it has the same dimensions as V2 in general except the clip goes where the bolt head used to be. If that assumption is correct, it should work without a problem. The quick release system for cleaning the H3 is made for pre-V3 bolt folks so you don't have to unscrew the whole thing just to clean it, but the V3 just slides out if I'm correct so it's of no use there. But' it shouldn't get in the way. Once I got a hold of a V3 bolt I was planning to do an update on the extruder with smaller overall dimensions. On my motor the small gear seemed glued on, but I used a big screwdriver as a lever to slide it off the shaft. The length of the M4 bolt is proportional to the length of your spring. It should be a spring you can't easily compress with your hands. Mine is ridiculously oversized but that's what I had. I'm no engineer though, and about springs I know next to nothing, but whatever works on any other spring loaded extruder should work here. My extruder was behaving strangely the last few days but I have isolated the problem and a small update will be on the 'verse today or tomorrow. But overall, I've printed at least a hundred prints on it so far. It is by far the easiest printing I've done since I got my UM. I know I'm probably subjective but I would love to see other people testing it out so I can improve on the design faster.

Where could I find some info on that E3D "v3" hotend? Tried googling around and found nothing. Thanks. EDIT: Nevermind, found it. Guess their SEO sucks.

If you're using 0.2 layers, then I think your head is definitely too close to the bed. Also this could be a combination of that, and over-extruding. To be absolutely sure, recalibrate the extruder in Cura, extrude by hand before prints, and start printing immediately after doing the hand extrusion (remove excess plastic before printing, of course). Also raise the platform a bit. If you are using opaque filament, then at 0.2 layer thickness, you shouldn't really have any semi-transparent lines like you have on the video. At least in my experience.

Well, the spring loaded system is what makes the lock work so well. I had a version without the spring but it was abandoned because tension adjustment was a mess. I designed at least four different idlers and never got it to work properly. I think the bearing and the spring are well worth the trouble. When I started I wanted to use as much of the original extruder as possible but that proved to be really frustrating, so I just went with what I thought best.

I've added the instructions finally.

Great stuff! I really admire your tinkering skills And I see you've printed a KNRLR, hehe. Have you used it? I like your nozzle hack with the steel part, I've never had a plug, but I suppose it could solve the issue many are having. Your prints look great and I suppose they will look even better with time. I also like the Audi bushings, . It would be cool if they were from an Audi R8 so you could have race car parts in your printer, haha.

I would bet that it has perfect thickness all around. But it's too soft. I got a roll of white PLA from Ultimaker last year when I got my printer. I spent a month tuning the printer thinking I was doing something wrong, but as soon as I swapped that white filament for something else, it became obvious that the printer worked perfectly. I don't really get why this happens, but beside the UM white, one other roll of material I ordered from reprapworld, i think, demonstrated the same properties. The bolt just grinds it too easily and too often.

So I've been silent about this for a while, but I was busy testing and redesigning. After this version which is on the photos in previous posts, I've made a second version which I used for the last month or two. It worked good but I wanted to add more features to it and change some things based on gathered experience. So, here it is. Hextruder V3 or H3. I won't spam the forum with pictures since everything is on the 'verse already, but here's a sneak peek: http://www.thingiverse.com/thing:27626 So check it out. All comments and questions welcome.

Hi guys, Does anybody here know how to design spur gears in Autodesk Inventor? Being an Inventor noob I'm kinda stuck at the spur gear designer window. I can't seem to get what I want from it. And that is 2 helical gears 47 and 9 teeth or something similar, 45,8 mm away from each other from center to center. Whatever I try to do, I get all sorts of Unit correction errors which I don't have a clue about. Any help andor explanation would be much appreciated.

I used to lubricate the rods on my UM with multi purpose grease, something similar to what shipped with the UM. And I thought it worked fine. Yesterday I found a bottle of Michelin precision oil for bicycle chains I bought a while ago and forgot about, so I cleaned all the grease and put on a generous amount of this instead, and WOW! My UM just got twice as fast. I used to be able to print at 90ish mm/s and move at 150, yesterday I printed at 150 and moved at 300 without any hiccups. It never sounded better and the head moves effortlessly when the motors are off. So my advice to everybody who hasn't yet done it - ditch the grease and get yourself some precision machine oil, your UM will thank you. Oh and one more thing while we're on this subject. Don't use WD40 to lubricate the rods. It will seem very good at first, but in the long run it will ruin your rods.

The shape is a blocky and sharp mostly on purpose, I come from an architectural background so my definition of pretty mostly consists of blocky shapes with sharp edges. I'm not sure I get what you mean by depth here. The extruder body is a bit shorter than the stock UM extruder, and also a bit taller. But the whole thing with the idler and screw is roughly the same size. I also tried to avoid the springs since I was too lazy to order some. The thingie is actually just a spacer and the bolt is my own spiked bolt (see first post). It has one problem though, it tends to twist the filament around while pulling it, so it's not really good for very long prints. I have to change the design of the bolt a bit. The gears are the same size as the ones on wade's extruders seen on thingiverse. I'll mirror them so the orientation is correct. Although the difference is probably small, everything counts here I suppose. I've printed many objects with it now and I'm very satisfied. It is not ready for publication yet, I still want to perfect some features. But, most of the small problems I had come from the custom bolt and not the extruder design, which is good.

I'm a bit short of time due to work, but I was thinking of modifying this design to make real knurled bolts when I catch some time off. The main operating principle would stay the same - a printed gear as a guide (but a more precise one), but you would cut the bolt twice, at 45 degree and -45 degree angles, to produce a knurled pattern. If anybody has any suggestions on that, let me know.

Now this is exciting news. I'm sure you'll have it up and running in no time. Can't wait to see it working.

Yeah well, I did. But grid rectangular isn't really what I want, Netfabb's infill is more of a line infill which looks like grid rectangular without the massive amount of jerky moves. And I can't even begin to understand the logic behind grid hexagonal, it does have hexagons here and there but isn't much of a grid really. At least from what I sliced with it so far. @Daid: Ah, I was kinda afraid you would say that, haha. Thanks anyway.

Daid, I know this might be a dumb question, but the thing I came to love most about Netfabb is the way it does infill (and since I started using Cura, that and raw speed are pretty much the only things I miss from Netfabb). I print a lot with transparent plastic and it really looks good on those, plus, it seems more sturdy than the default line infill in Skeinforge, at least in my experience. Now, I know this is a Skeinforge feature but since I presume you delved into Skeinforge quite a lot while programming Cura, I have some hope you could do something like that. Is it possible? And thanks for an awesome piece of software. :mrgreen:

Well, here it is in action: I noticed a few problems after printing for a while so I have to modify some details before publishing, but nothing serious so far.

I made a new extruder design for my UM - the Hextruder. No, it does not extrude six filaments. It's named like that because I'm a huge board game fan and I love hexagons. Also it has a honeycomb pattern on it. There are some aspects of the original UM extruder which I hated: -I had to turn the thumb screw till my thumb bled to get decent grip on the filament. -Some filaments I have would strip instantly however tight or loose the thing was. -The margin between loose and too tight is very small. -It always gives me problems when I try to open it. And so on and so forth... I think most of us hate something about it. So, I wanted to make a different design which fixed some of the above, while requiring no fancy parts (it's a hassle to get anything CNC'd in Croatia), and recycling some non-plastic parts from the stock extruder. -It has fishbone gears, mostly because they look ubercool, and also because they seem to be very precise. (Did I say they were pretty?) (Maybe stupid question for engineers: do fishbone gears have a preferred direction of rotation?) -It has an idler with a 608ZZ bearing, which is very easy to obtain anywhere. -You don't have to break your finger to tighten it, and it opens easily. I printed it out yesterday, and my initial test was great! The little gear on the pics is actually printed with this extruder. It's tough, pushes the filament like crazy and requires very little force to tighten. I used a spiked bolt made with the KNRLR(http://www.thingiverse.com/thing:21782) and it works pretty well, especially since the bolt I used was a test one, and not cut very precisely. I have to do some more testing before I publish it but I wanted to brag about it here first. The only problem so far is that I missed a fraction of a mm on the part that holds the bowden clip and have to fix that to be a little tighter. So expect a more detailed report soon.

The gear is designed to be a bit tight so it screws on with a bit of effort, then you secure it by tightening the M8 bolt to it. The same way the UM extruder gear is secured in place.

As the title says, I designed a small contraption for easy DIYing of spiked extruder bolts. Really comes in handy if you are designing your own extruder and the UM bolt doesn't fit your needs. I'd be really grateful if some body could port this to OpenSCAD and send me the files to add to my thing, since this isn't really customizable. The name is cheesy and a bit misleading but it kinda grew on me so I left it like that. Hope you all like it. http://www.thingiverse.com/thing:21782 Edit: Doh, forgot to paste the link!