armstrom

I have completed my machine and also see this Z wobble issue. I haven't pulled the drive screw out yet to verify that it is straight (I'll do that tonight) But what other options do I have? When In installed the Z stage I noticed that the two 12mm shafts really want to pull the structure at the back apart. I suppose that's why it was designed with a slip-fit between the right and left halves, but it seemed kind of odd. I had some binding the first time I installed the Z axis so I disassembled the structure that captures the big brass nut and centered it better. Could that still be the issue? Any tips are much appreciated. -Matt

Thanks for the feedback! I'll keep pushing through on the assembly. I just didn't want to get "done" and have to back up so far to fix something. Also, thanks for the link to the tensioner. I like that design better than the others I've seen that simply clamp onto the belt. However, the part I'm talking about is the screw used to hold the center lever down. If you look at this picture: http://www.thingiverse.com/image:106571 It's the screw/nut that you can see on the right side of that block. As you can see in the picture the little piece of wood is thinner than the slot it sits in (it's all the way up at the top of the slot in that picture with a big gap underneath). The gap under the piece of wood is where the nut ends up. So when I'm trying to tighten the screw the nut just spins. If the piece of wood were the same size as the slot then the nut would stay captured down in the vertical groove and not spin. Oh well. Again it's something I can easily work around. I think one of the first things I do (after printing the standard upgrades) is to design new blocks for the XY gantry. I don't understand why proper linear bearings are used in the head itself but copper bushings/slides are used on the fixed axes. I think I will design some blocks that use 8mm linear ball bearings and include a more robust tensioner system. The laser cut design is really cool and well thought out but something much easier to assemble/adjust could be printed pretty easily. Edit: On a positive note.... I measured my fixed axes with my CMM and they are within a few seconds of square and parallel. Very impressive considering it's all located by laser cut wood The right and left axes were out of parallel the most.. only about 1 minute though. -Matt

I'm moving along with the assembly of my Ultimaker but I'm running into a few areas that concern me. 1) Squaring the XY carriage. I don't understand how this is to be done using part 3B. The part itself has rounded ends and it's being pushed into a rounded corner (the opening in the top of the machine) and this is somehow supposed to give me a repeatable length? The pictures on the wiki don't seem to help as they are illustrating the very problem that I'm seeing. 2) The friction of the XY carriage is very high at the moment. I have all of the set screws loose in the pulleys so I know all the friction is coming from the copper bushings. I noticed the 6mm cross-bars (the ones going through the extruder) required significant force (more than I would have expected) when first inserting them into the linear bearings but once they were inserted they moved very smoothly. The font-to-back bar fell out as I was trying to mount the extruder in the machine. Granted, I have not yet lubed the axes so perhaps that will be a cure-all but I'm still a bit concerned. 3) When mounting the extruder and cross bars into the machine the instructions say to insert the left side first, Then "raise" the other bars up into the blocks. Well, that works for the front and back as the openings are in the bottom of the blocks but the right block is just like the left in that the bar can only insert from the top. This made for some tense moments as I saw the cross bar flexing slightly as I tried to get it into the final block. 4) Belt tensioners: The part C (little wooden cross piece with a 3mx10 bolt and nut on it) does not seem to be thick enough. It is able to move vertically inside the slot . This allows the nut to come up out of the groove that normally captures it. So now when I try to tension the belts the nut just spins freely. I "solved" this by wedging a small flat head screw driver between the wood and the nut so I could tighten it, but something doesn't seem right to me. So far that's it. I've found some errors in the wiki but nothing too serious. -Matt

I don't get this either. My axes still have quite a bit of friction (granted, they are not greased yet). I understand what the instructions are asking me to do, what I fail to understand is how it is helpful. The openings in the sides of the frame are radiused and so is the end of part 3B. However, the only way to make contact between the wooden block and the frame is to use part 3B such that the radiuses don't fit together (not that they're the same anyway). But that leads to the part wanting to push away from the side of the frame as it moves along the radius of the corner. Clearly this is not a repeatable setup. Wouldn't a better solution be to have a pair of gauges in the shape of a Z (but with a straight center section, if that makes sense). You could then gauge the distance between the cross rod (the ones through the extruder carriage) and the edge of the frame. I have my partially completed ultimaker with me today at work so I will probably bring it in during lunch and measure the perpendicularity using the portable CMM on my desk I just need to prepare myself for the shock of how bad it's going to be. I'm used to instruments that are repeatable down to about 5-10 microns so bearings pressed into wood will not quite measure up (so to speak). I have some other questions/concerns about the assembly but I'll save those for another thread. -Matt

No problem. Luckly I finished assembly of my frame last night so I don't have to rush home to see if I ended up with two left panels My order arrived on Friday. Assembly is quite straightforward. They label EVERYTHING. One thing to keep in mind is that the cable organizer pack is no longer labeled as such. It's inside the mega pack though, in a separate plastic bag. -Matt

Don't fill in the field. I have that issue as well. I think they have the check in the form code backward. Just tell them your order number in your message. -Matt

You can run LEDs off of any voltage you want. If your LEDs already have a current limiting resistor (they probably do if they are labeled as 12V LEDs) then you will just need to add an additional resistor in series with the LED to adjust the current limit for the higher (19V) power supply voltage. Regular LEDs consume VERY little current compared to everything else in your printer (~20mA). If I make some assumptions about your LED I would guess that it has around a 560 ohm resistor in series already (20mA maximum current, 12V, 2.0V forward LED voltage). To safely run off of 19V you can just add another 560 ohm resistor. However, that will keep the current through the LED roughly the same, if it's too bright or you don't mind it being a little less bright you can always run it with a 1k resistor without any issues. -Matt

You can try these guys: https://www.protoparadigm.com/ I bought two spools of PLA from them. I have not tried them yet as my printer is still in the hands of DHL but they seem to have a reputation for sourcing very good quality PLA (tight tolerances on diameter). They even have an ultimaker -Matt

I've never installed ReplicatorG but when installing Cura it deploys the driver for for the Arduino hardware automatically. Keep in mind that the drivers are not signed so windows pops up a big, nasty, red warning box during the install asking if you're REALLY sure you want to install the unsigned drivers. They are safe so go ahead and install the driver. Now, if you don't have administrator rights on your PC then you may not be able to deploy the driver at all. Try right-clicking on the driver install and choosing "Run as administrator" and see if the driver install will complete. Once you're able to successfully run the driver install it should fix the issue of your Arduino Mega showing up as an unknown device. Once the drivers are installed ReplicatorG should be able to find the virtual COM port that has been assigned to the Arduino and you should be off to the races. -Matt

Looks like a manual crank for the Z axis. That used to be a common trick with the old repraps (before the switch to two Z axis steppers) When the outline of the part is being printed you manually crank on the z if it's not adhering properly. At least that's what I've seen some of the guys at the hackerspace doing -Matt

Yeah, I'm hoping once I get my printer and start working with it on a regular basis I will become motivated to contribute to some of the software projects out there. Perhaps work on a slicer of my own. GPGPU stuff is getting much easier with some of the new libraries. If you try to code directly for Nvidia CUDA or ATI's Stream API things can get complicated. Especially if you want to support both. But with OpenCL and Microsoft's DirectCompute things are starting to become more standardized. It's the same old stuff all over again Remember back in the early days of 3D gaming there were many competing standards. Direct3D was just starting to appear, OpenGL had been around for a while but was mostly relegated to university projects and high-end graphics workstations. Back in the mid 90's 3Dfx Glide API ruled the cutting edge gaming world. But then everything started to coalesce around a more mature OpenGL API and microsoft's DirectX. Same thing is now happening with GPGPU today. It's an exciting time -Matt

Yeah, my concern with the free software packages is the slow slicing time. I plan to produce a variety of parts, some will be fine to just slice at normal 0.1 - 0.2mm layer heights so free software will work well for that (planning to use Cura since it seems to be very well regarded). However some of the parts I want to print will require a finer surface finish so the faster slicing combined with the half-height outer layer feature of netfabb seems to be what I need. I will never understand why products like Skeinforge are built in interpreted languages like Python. As a software engineer with 11 years experience in the 3D measurement/CAD world I understand how processor intensive cross-sectioning and tool path calculations are. I understand the JIT compiled PyPy runtime helps a bit, but I can't help thinking this could use a port to C/C++ and perhaps some GPGPU optimization. I hear Slic3r is significantly faster than Skeinforge but has other problems that make it less than ideal... Hmm... I guess I'll start with Cura and keep an eye on Netfabb to see if they resolve some of the issues in the next release. Thanks for the feedback guys! -Matt

PLA often smells sweet when you are printing with it. If you were printing with ABS it would smell, but it wouldn't be sweet Green PLA smells like pancake syrup to me. -Matt

I see a lot of people frustrated with bugs in Netfabb, but I also see that they recently released an updated version. What's the general consensus with regard to the cost/benefit of Netfabb? I recently ordered an ultimaker with the standalone controller so I plan to do most of my prints from SD card anyway... Would Netfabb be worth the 150 euro cost? Or are there still too many bugs? -Matt

When using an aluminum bed you still put down a layer of tape or sometimes glass. Most people use an aluminum bed because they want to heat it so they switch from blue tape to polyimide tape. Both of these are electrical insulators. But for leveling, yes, you are correct that's a helpful trick. But you don't need the aluminum bed to do it. Check out this video: -Matt

Do share... Details? Does everything fit well?

Thanks for the feedback. Yeah, I didnt' think about that issue.. hmm.. Well that's the type of feedback I needed! I guess a flex tube will have the same problem no matter where the stepper is mounted. It could be mitigated slightly by centering the stepper vertically above the X/Y envelope but that would only spread the errors out. Hmm... Bummer Edit: Well... on second thought.. if you keep the axis of the tube rotation parallel to the Z plane then the X/Y movements shouldn't cause additional rotations. It also eliminates the need for the right-angle gear box... however, I'm not sure that a flex tube can bend that sharply.... I'll have to play around with the idea some more.

I don't yet have a UM but in my research I noticed a fair number of people having issues with the extruder design. Also, it seems the current design doesn't allow for filament retraction very well. My idea is rather than try to fix the bowden tube design simply eliminate it. Move to a system where the filament is pulled into the hot end directly like on repraps. Now, I ALSO don't want to give up the fast print speeds and additional stability that comes with the very light weight printer head. Obviously, mounting a stepper on the flying print head will ruin that... So.. Don't! I think a good compromise would be to use a flexible drive shaft (like the flex shaft that comes with most dremel tools). Keep the heavy stepper and gear reduction mounted to the back of the box (but rotate it so the shaft points up). Then run a flex shaft up in the same basic location that the bowden tube runs in the current design. Then you mount a light-weight right-angle gearbox (1:1) on the print head to adapt the flex shaft (coming in vertically) to rotate the knurled bolt. This will add a bit of weight to the head, but not nearly as much as adding a stepper motor. The bowden tube can be replaced with an oversized tube to route the filament. The right angle gear could be something as simple as an off-the shelf drive like this one: http://www.amazon.com/Huco-332-31-2-Z-M ... pg__header or you could piece something together out of a printed housing, some bearings, shaft and a set of bevel gears. So the power transfer would go like this: Stepper->Gear Reduction->Flex shaft->right-angle gearbox->Extruder bolt. An alternative would be to mount the stepper at the top of the box with the shaft pointing toward the front. Then the flex shaft would only have to bend 90 degrees rather than a full 180. A small bracket could be hung off the back to move the stepper as far rearward as is reasonable to reduce the minimum bend radius the shaft is subjected to. I'm curious if anyone has ever considered a modification like this to get the best of both worlds? (lightweight head without a bowden tube). And if anyone tries it before I get a chance a little mention would be nice -Matt

Thanks for the reply. It looks like there is at least one redesigned extruder feed system. I belong to a hackerspace and most of the members there have one of the reprap models. I'm still trying to figure out if I can justify the extra cost over one of the other models. I'm not a fan of the build platform moving in two dimensions but it's hard to argue with the price difference... If I could be sure the ultimaker would be reliable and also give the type of high quality results I've seen online it would be easier to justify. But if I'm constantly pulling my hair out trying to get a good print I'll feel pretty bad :( Also... is it simply not possible to retract the filament to avoid hairy prints? I understand this is not currently supported but it isn't clear to me if it's a limitation of the firmware or a fundamental hardware design limitation. —Matt

After seeing the print quality people have been able to achieve with the ultimaker I've become very interested in purchasing a kit. However, after reading the forums I'm a bit put-off by the number of problem reports I'm seeing related the the extruder system. I'm not seeing any clear indication of what the root problem is. Some people claim it's the knurled screw, or a poorly assembled interface between the tube and the hot end... or one of a number of other theories. So.. what's the current state of things? If I order a kit today should I expect to fight with extruder problems or are they isolated problems? I understand that being a kit implies there is a great deal of variability in the final product due to assembly but I would like to know that I will be able to achieve results similar to those I see on the ultimaker site without having a huge failure rate due to extruder problems. Also, I understand that a heated bed is in the works. I assume this is something that will integrate directly with the electronics of currently shipping units (it seems to already have outputs for a 12V heater and an input to read the temperature). Thanks! -Matt