jonnybischof

I want to avoid that because there might be problems with this. See: http://umforum.ultimaker.com/index.php?/topic/4177-improved-z-stage/ And I don't want to add a whole other leadscrew and motor in the front, because when I'm done, the front will be the only accessible side left to reach into the printer (crossflow fan). It doesn't take that much more stiffness. The UM1 does work after all. Most important thing is to eliminate drooping by eliminating the wooden parts. And add as much stiffness as possible. But I don't think it's necessary to reinvent the wheel here.. /edit: Just to pick up some thoughts from that other thread: - I don't think that swinging in X direction (left - right) will be an issue with my current steel setup. The Misumi bearings are very tight, and the 12mm shafts definetly don't bend. They're rock solid. - It could be possible to add one shaft in the front which doesn't go all the way up to the top, but reaches only just under ther x-y-gantry. But I don't really see the benefit of this so I'll leave this out for now. - Adding more weight to the z-stage and the whole machine could make a big improvement. I will definetly experiment with that. There is some space in between the shafts and the leadscrew to add weights (Dim3nsioneer showed http://umforum.ultimaker.com/index.php?/topic/5541-let-your-um-original-gain-some-weight/ last week) This, plus moving the lever attack point a bit upwards, should improve things more than enough. I hope

What kind of filament do you use? Different filaments will need different printing temperatures... Some ABS prints well only at 260°C... I tried Ultimaker red ABS a few weeks ago. Part was completely useless, didn't take much force to rip it apart layer by layer. Smart ABS from Orbi-Tech however is strong enough that I have to beat it several times with a hammer in order to crush it. Even then it's hardly the layers which come apart, but the whole structure of the part. There is also good ABS and crappy ABS on the market Haven't done enough testing to say the Ultimaker red is bad, I probably just printed it a few degrees too cool. Also, don't use the fans! All fans off for ABS.

You mean like this? Sure, not pretty, but I mean the principle. Of course I'd make it more triangular than the "T" it is on the picture, but I was just scratching that up... I think I understand why that would make the arm stiffer. You move the attack point of the lever? The problem is, that for now I won't redesign the frame. I'd need to cut out that space in the bottom plate, make the 12mm z-shafts as well as the leadscrew longer, and add a construction which is sturdy enough to reattach these parts again a bit lower. The only reasonable thing would be to actually just lengthen all the side parts and make the shafts / leadscrew longer. So, in the short run, my only option is to just sacrifice more build height if I want to go triangular. Maybe some time I will redesign the frame, but right now I need a working printer as fast as possible. I'm already very pleased with lasercut metal parts ETH Zurich has some steel sintering technology (I don't recall how it was called exactly). The chief mechanical engineer at "my" last company showed me a part which was made there. 90% the strenght of regular steel, but with almost microscopically small structures (it was a nozzle for an epoxy dispenser, making lots of little dots and including a particle filter). Maybe.... What if I made the parts so that you can just choose whether if you want an L or T shape? I can make all the other parts in a way that they would fit both variants of side arms. This way I could make both versions and compare. I don't yet know how I'm going to get my chrome nickel steel lasercut, but if I get a somewhat reasonable price.... Or I could start with plywood dummies. I can do these at the FabLab almost for free. OR, maybe I can CNC-cut my beloved chrome nickel steel there... I doubt it, but I haven't asked yet (will visit the lab on friday evening). /edit: LOL Actually I don't have to change anything at all in order to make a T out of the L: Im using these bearings. (LHIFS12, choose 12mm and quadratic flange). I'm planning on mounting them the same way as the UM2 does it: sitting on top of the bottom plate (the shorter end goes through the hole in the bottom plate which takes care of precise alignment issues). Instead of that, I can just mount them to the bottom and / or turn them upside down, so that the longer side sticks out below. There you have the triangular shape I could even make the whole thing lower again, and give the option to turn around the top bearing for more stiffness, or keep it as it is for more build height. Jeez such freedom The arms themselves should well be stiff enough so that it doesn't matter if they stay "L" shaped.. By the way, I noticed that these bearings will stick out 4mm on the bottom even when mounted upwards. That's actually a mistake I made, but doesn't hurt much. However it does mean that I can add some more meat to the arms on the low edge. /edit: There are also longer versions of these bearings, so you have like 20 different height-, L-, T-, or whatever configurations

I'd be very interested to print something like that! I'm putting up a workshop, but these emergency buttons cost a fortune!

That's exactly where the UM excels: feeder not mounted on the head. It makes some things much easier... If the printhead gets heavy, you need a much stronger gantry (or move much slower) etc. etc. ... So, it is definetly not trivial to make the UM bigger. That's a good first conclusion I think. I guess I won't attempt to build one. Seems like a lot of work without guarantee that it will actually work well enough. (Besides, I have enough other projects waiting to be realised o.O) If you could just lasercut some bigger panels, buy longer belts, shafts and maybe a few other parts, that would be nice. But it seems there would be some major problems (like the bowden length) that can't just be fixed without having to redesign half the machine...

Why did you have to replace the mainboard? Was there some electrical surge, or a lightning strike? Because if your first mainboard was destroyed, it may have taken the LCD expansion board with it... You can't do much wrong with the UM2 EXP connectors: it's impossible to connect them wrong (reverse polarity), and confusing EXP1 with EXP2 "should" only make it not work, but not damage anything. Of course there's always the possibility that your flat ribbon cables are broken. If you have a multimeter, try checking the cables for bad connections. Or you can just take a close look at them and see if everything seems ok. Chances for bad cables are usually pretty low, especially if the wires are never moved around or excessively bent.

Carbon fibre is very flexible, so the sheets would need to be fixed very well on all sides. Steel is much stronger... I also ruled out carbon fibre plates for me because they have something like 85°C maximum operating temperatures. "Could" still be used, but it's not so beautiful... Also, 85°C max. operating temperature does not imply that the sheets can't become a little softer already, which would probably lead to deformation. And then, there's the fact that carbon fibre plates are ridiculously expensive (depends where you buy them...). Maybe that evens out when you pay a lot for lasercutting cheap steel, compared to paying less for lasercutting expensive carbon. I'd have to ask in the FabLab (got membership this week @ FabLab Zurich ) if they can lasercut carbon fibre. That would make it worth considering. Thanks for the hint!

For me, setting the infill overlap to 16% (15% is standard I believe) has always worked well. If I set this higher, then I get notable overextrusion on the overlaps. First of all, you should set it back to 15 or 16%, then try to solve the issue by doing what the others said above. Leaving it at 20% will most probably lead to bad results in any case... The fact that it occurs only on top and bottom, but not left or right sides, suggests that you have a backlash / belt tension problem, but only one one of the two axes. Still check and tighten all belts so that you can be sure this is dealt with. Maybe check the pulley setscrews, they need to be really, really, really tight.

If you need your filament urgently, I'd suggest you order them from another supplier where they are in stock. Ultimaker is known for having huge lead times for filament. The forums are full of people waiting for their stuff. It may sound harsh, but they had it coming for a long time now... Where are you located? There are many good filament sellers around the world. I'd particularly mention colorfabb (Europe, worldwide shipping) and faberdashery (GB, worldwide shipping). For the US, I'd try ProtoParadigm, though I haven't ordered from them before. But my preferred black PLA comes from them, really good stuff (probably not pure PLA but some mixture). Btw. I've never ordered from Colorfabb either. Don't know about their lead times. Faberdashery was very quick for me, they sent out my order the next day (I ordered in the evening). /edit: By the way, congratulations on your UM2 purchase! It's a great machine and I'm sure you'll be satisfied with it! Don't expect it to be free of any flaws or maintenance. There is no such thing as a maintenance-free 3D printer...

*Muaha* I wanted to suggest the very same thing, but then I found a problem with it: If you do that, then you still have to make the bowden tube long enough to reach into the corners. But when that assembly moves right into the center of the platform, it will develop a lot of (most probably too much?) tension because the bowden will be much too long. So we'd have to compensate for that... If the feeder assembly were able to slide up and down, it could compensate the bowden length. But I don't know if it would suffice to have it "move freely on a vertical slider" or if the friction / needed force would still be too great. Also this would take a lot of space upwards (not a real problem, but it means a huge loss in elegance...). Or you could mount the whole feeder system on rubber bands, being able to be dragged around. That also means a lot of force on the printhead which is bad. I guess even just a little more force would already be a problem because the head is supposed to move very quickly. If you have a large build volume, being able to print fast is very important or you'll have 100+ hour prints... /edit: If you say "gantry", do you mean another x-y gantry on bearings / bushings which will move together with the printhead? Maybe it could work if you add a whole second gantry, with shafts, motors, pulleys & belts that moves together with the printhead. If it were just "free floating" on an x-y shaft gantry, there would probably be too much friction...

Thought about that, too. But 2mm chrome nickel steel is REALLY strong I'm not yet done however. I'll probably take out some material from the bottom plate in order to save some weight. Then I'd need to compensate for the loss in stiffness by adding a center "wall" into the bottom plate. Kinda like copying the front wall into the center of the piece. Maybe even make one from the front to the rear, or instead of orthogonal, make them diagonal. I'll see where it goes.. I usually don't plan my constructions much in advance but develop them as I go. Maybe not the best technique because I end up deleting stuff over and over, but I don't have the experience to be able to think up a good solution right from scratch... /edit: By the way, I'm surprised no one's screaming "WOOOT" yet when I say "chrome nickel steel". This z-stage will probably cost somewhere around 300 Euros, including build platform and heated bet assembly...

Just because you'd sacrifice a lot of build height if you do it any differently.. I hope making it out of 2mm thick steel will get rid of the problem. Use brute force when elegance is not easy to achieve /edit If it's not strong enough, I'll just use two 2mm steel sheets per arm... (Use more brute force when brute force is not enough)

Right - longer bowden tube needed. Shouldn't be much of a problem though. But it's a needed part... You're right, retraction length would probably need to be increased which also increases retraction lag. Could be that increasing the build volume means losing somewhat of printing quality... I think I'd definetly need bigger diameter pulleys, because the belts must be kept apart from each other. I don't know about tension. Does it really make a difference? Stronger belts could be an option, if necessary.

LOL, it's the first time (since 14 images) that someone tells me that this doesn't work -.- Should be ok now, I set the gallery to public. I thought that wouldn't apply to directly linked pics... Lasercutting steel is a whole different story than plywood or acrylic. It takes a laser that packs a bit more of a punch As for the steel designs, I will do these so that a professional manufacturer can produce them. Means I will just draw the exact dimensions that I desire, and the manufacturer will do the adjustments. If you want to make the same platform out of plywood, then there's a lot of changes that will be necessary. 2mm thickness will only work for something similarly strong as steel. Also, a heated bed is pretty much a standard for upgraded printers, so I won't waste any time making drawings for materials which aren't heat resistant. Acrylic is not suitable imho, because it doesn't really like continuous heat while being under pressure. The UM original files are made just for that purpose - lasercut plywood. That's why they don't bother much about tolerances - no avail with plywood anyways. Instead there's a lot of space between parts to allow for adjustment. Don't think that with plywood it can be done much better than the UM original files. The only way to improve the z-stage is to make it out of a more rigid material.

Good to know the Z-motor can take some additional weight (lots of additional weight coming up for my next mod...)

Ambient temperature shouldn't have more of an effect than with the standard size, I guess (?)... If you use the same 6mm plywood, maybe you get some negative effect. Though I have to say the standard UM frame is amazingly sturdy. But wood does have very high, and most importantly uneven, thermal expansion coefficients. Aluminium is not that much better (and it's useless when you want to build a heated chamber), but chrome-nickel steel should have pretty much no measurable thermal expansion in this application. I was thinking of making a double-layer construction: 3mm plywood over 1.5mm chrome-nickel steel. That makes for a very sturdy construction and provides good thermal insulation at the same time. Maybe, the stuff I'm using for my new build plate could be useful, too. But it's really expensive... Showstopper for 99% of all hobby builders.

I've been thinking about making a larger version of the UM. (something like 500x500x300 mm build volume) If it were trivial to do that, the UM would probably already be a bit bigger. But what are the main requirements in order to make a bigger printer? - The electronics and firmware shouldn't have any problem handling larger spaces? - Cura doesn't seem to have a problem with a 500x500x300 custom machine. - The shafts will be longer, and therefore any straightness-issues may become bigger. So you can't use the cheap banana-style shafts. Ok, but good quality industrial shafts come in 2000mm standard lengths, so they should have some degree of usefulness or they wouldn't produce them in that length? - Longer belts shouldn't be a problem? - When does build height become a problem? - The frame needs to be straight. No problem if the right material is used... - Are there any other problems I'm not seeing?

For now, I didn't include any notable tolerances where you could adjust anything. Instead, I hope that a rigid, precision lasered or CNC'd construction will actually be parallel and make any adjustments obsolete. I don't know if that works in practice, I'm not a mechanical engineer... /edit: It may be wise to save as much weight as possible on the parts which are far away from the shafts, but add as much weight as possible near the shafts. Stupid thing is, the build platform will be exactly the opposite of that... :(

I started with that thought, too. But when I assembled my second z-stage for reference purposes, I decided to completely ditch the standard wooden parts and replace all of them. I'll keep the lead screw nut because these are pretty expensive. Mounting this one is a bit tricky, but I found that the parts with flanges use like 5mm mounting holes. Why 5mm?? And M5 screws don't even fit because the holes are too close to the body of the part... I did also ditch the linear bearings, and for two reasons: 1. The UM original bearings seem to be very low quality. I will check all four I have as soon as I take my first UM apart. But the one I compared to a Misumi bearing was just awful. 2. Mounting gets a lot easier with flanged bearings. So, I will use flanged bearings which are easy to mount (they also have huge mounting holes, but I'll get them fixed somehow...) because they have a "pilot / guide". And, I will use two bearings per shaft, one on top and one on the bottom. This will add more rigidity because overall, the length where the z-stage is fixed to the shafts is longer. (about 100mm height compared to 70mm original). So yes, I will lose some build height, but I can live with that and it happens anyways with the heated bed. Here's my WIP: Seems a bit messy, but it's just Sketchup... I only draw every unique part. The arms for example are ambidextrous, so I won't draw the right one... These parts are 2mm thick, the idea is to have them made of chrome steel or some hard aluminum alloy. Should make for a nice rigid part... I used the same mounting technique as the original UM parts (but with square nuts, I wonder why they don't supply square nuts with the kits...). Endstop "plungers" will be screws added at the correct position (easy length adjustment). As you can see, I took a lot of inspiration from the UM2 but made it much more rigid (the UM2 doesn't have the side arms at all). /edit: By the way, I'm using three point levelling with M4 screws and much stronger springs. This should make it possible to level (my first machine can not be levelled perfectly because four point levelling just doesn't work) and remove most of the wobbling / rattling. /edit2: Forgot to mention: The current design is made for CNC milling with a 2mm tool (I hope that works for chrome steel, I have no idea...), that's why there are a lot of "unncessary" dents in the parts. If possible, I want to have the parts lasered which will simplify the construction a bit. If the thing works and I publish it, I will keep both versions and maybe even add versions for different material thicknesses. It shouldn't be too difficult to just make this out of 6mm plywood instead of metal. /edit: Just ordered the linear bearings needed for this setup... They should arrive May 16th.

Das Faberdashery Filament hat 2.85mm. Der "Verkaufsname" ist 3mm, das wird einfach aufgerundet. Habe ich in diesem Thread übrigens schon einmal geschrieben...

Always interested

I'm wondering on how to attach the bearings as well... I'll definetly have to redesign the entire z-stage, so there are several possibilities. One would be to use flanged bearings. The problem is, I want to have two bearings per shaft. So if I attach the bottom one with a flange, ok. But how do I mount the top one perfectly in the same alignment... ... Just had an idea Will put it to paper and report back... /edit: Seems like this might just work. It's not going to be the cheapest solution ever, and it's probably going to be heavier than the whole rest of the printer, but at least it'll be nice and solid. Found an easy way to connect 2mm steel plates using square nuts and short bolts, I hope this will work The only bummer is, I have to buy new 12mm linear bearings again, need flanged bearings...

I've been toying around with the z-stage, and I've noticed something: The Ultimaker 12mm linear bearings are totally crappy?!? I noticed that I wil sacrifice a lot of build height if I try to use two linear bearings per side instead of just one (in order to increase stability). Incidentally, I compared the Ultimaker bearing against a bearing of the same dimensions from Misumi. While the Misumi bearing (actually low-cost model from Vietnam, not even Japanese made) slides without any friction and with almost no wiggle at all, the Ultimaker bearing feels like they used cubes instead of balls, and it also wiggles a lot more. Note that I used the Misumi precision shaft for that test, but it seems like this Ultimaker bearing is a real no-go. I wouldn't have thought it were that bad... Did anyone have a similar experience?

Yeah I know it's a ball, like a ball pen. But is this suitable for actual rotation? Won't it wear out quickly? I don't know what these screws are normally used for, but I woud have guessed they're just for fixing stuff in place (like any other setscrew)... Anyways, it's most likely better than a pointed setscrew. The screws shouldn't be tightened so much that they clamp the shafts anyways, it's just to hold them within their bounds... You could of course add another standard ball bearing, put in a piece which is made so that it can't slide out of the bearing and holds the setscrew... But that probably goes too far Working on the new super-sturdy z-stage & build plate right now. If all goes well, I'll machine my new build plate today. Received really nice material for it: https://shop.maagtechnic.ch/ishop/product/catalog/01/product/183735.xml (site is german or french only...)

That sounds very interesting! I was thinking about those screws, too. The good thing is you can choose either pointed or ball clamping setscrews... I already have pointed setscrews, but if it improves things, I'll get some of these as well. /Edit: Are these ball clamping screws really suitable for constant movement? These are not like ball bearings, or are they?