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Posts posted by jsamuels

  1. Zoev89 it's quite easy to figure out the power supply requirements, the heated bed is just a resistor and so Ohm's law tells you everything you need. The lowest resistance point along the temperature curve will be the maximum power required, so divide your voltage by that and you have the amps needed. If the resistance drops as the temperature goes up then the power draw will go down, it's no problem.

    Unfortunately I'm not able to adjust my power supply below 21V, so I'll have to source another one.

  2. Yes, that's the one. It is 1.8 ohm per the spec so I guess it's not defective. But with a 24V supply this will draw 24/1.8 = 13.33A

    When I drive this from a 24V 10A supply, the voltage measured across the power supply terminals drops to around 16.5V. So the heated bed is drawing around 16.5/1.8 = 9.2A and the power supply is current limited. It's not good to run a power supply like this.

    To actually drive this safely at 24V it seems I will need a 15A minimum supply.

  3. Can anyone with the ebay kit check the resistance of the bed (across pins 1 & 4 on the connector)? Mine is reading 1.7-1.8 ohms, I don't think it's possible to drive this from my 24V 10A supply as it will pull almost 14A. Indeed the voltage is dropping to about 16.5V under load and the supply got too hot to touch within 1 minute. I'm debating if I should contact the seller for a return or change to a 20A supply instead.


    Open source

    Just like the Original the Ultimaker 2 will remain open source. We dare to share our knowledge because we believe we can achieve even more when working together.

    Sounds great... where's the source? I looked over the website, wiki, and github but didn't find anything.


  5. If the clicking is coming from the back-right pulley you're pointing out in the video, try loosening the grub screw for it and moving the axis, to see if the clicking goes away?

    Did you already check these things?

    - Short belt tension

    - Rods and belts are in the same plane along Z axis... this thing will demonstrate :


    - Belts aren't binding on or rubbing the shoulder of the pulleys, and that the pulleys themselves aren't rubbing against the rod end bearings / frame.

    - The rod end bearings or rod ends themselves are not rubbing against the covers on the outside of the case.

    After you installed the belt tensioners, did you loosen all pulleys to allow the tension to equalize? If not then you would have more tension on the lower belt segment than you would on the top.

  6. I believe you just specify the T parameter for the M104/M109 command, T0 being extruder nr1 and T1 being extruder nr2...

    M104 S200 T0 ; set 1st extruder temp to 200, don't wait for preheat

    M109 S200 T1 ; set 2nd extruder temp to 200 deg, wait wait for preheating

    But you may need to send tool change first with M6, or change gcode to address extruder via A/B axis. I am not sure which one Ultimaker / Marlin supports.

    M6 T1 ; change to 2nd extruder

    G1 E10 ; extrude 10mm from 2nd extruder

    M6 T0 ; change to 1st extruder

    G1 E10 ; extrude 10mm from 1st extruder

    - or -

    G1 A10 ; extrude 10mm from 1st extruder

    G1 B10 ; extrude 10mm from 2nd extruder

    I don't know which is correct, it shouldn't hurt anything to test via console, but I can't be responsible if you break your Ultimaker. :)

    Either way you would likely need slicer support for dual extrusion, or handroll your gcode. I believe the development version of Cura has some support coming for this, hopefully Daid can provide some more info.

  7. I was quoted $175-200 (material included) at some local shops (west coast USA) for cutting out the UM frame from 6mm & 4mm plywood. I got a test cut and the tabbed joints fit fine.

    I didn't ask how much the plywood cost. But I know that plain acrylic sheet 1/4" thick is around $10-15 per sq foot, not sure how much you need for an UM offhand. I didn't find any place locally stocking metric-sized acrylic though. I'm not certain if 1/4" (6.35mm) is close enough to 6mm for everything to work perfectly... I think it would need some tweaking. And for the 4mm parts, locally it's only 3/16" (4.76mm) or 1/8" (3.18mm) available neither of which seem close enough to me.

    Polycarbonate would make a more awesome Ultimaker than acrylic and is way less fragile, and cost is a bit more expensive but comparable. Not too many places will lasercut PC at least not in 6mm thick. And the cut edge will be bad. Waterjet cuts PC easily though it leaves a frosted edge.

    Garolite (phenolic) could be really awesome looking, it's available in all kinds of colors and textures. But again not many places will laser cut it, waterjet is fine.

    Too bad we don't have an opensource waterjet project !

  8. You can start with the RepRap gcode reference (


    ), Ultimaker has the Marlin firmware and it supports most commands if the feature is present. The wiki does list for some commands if they are supported by Marlin or not, but others you just consider if the hardware support is there. For example the heated bed / heated chamber commands won't work on a stock Ultimaker as those features aren't present.

    Daid has a Marlin builder you can use to custom-build a firmware, you can add the 2nd extruder there in the configuration options IIRC. (



    I'm not sure exactly what revision of Marlin it uses, I can't access it currently.

    You can do what you want with moving the head to XY and turn on the 2nd extruder without writing any code in Marlin, it will just take custom gcode as no slicer will autogenerate it for you.

    Edit: Also look at the Marlin github


    Marlin.pde has comments for the list of supported commands.

    https://github.com/ErikZalm/Marlin/blob ... Marlin.pde


  9. It's a bit hard to see on your photo, but it looks like the wall lines of open print are not connecting in the X direction. Could indicate a backlash problem, usually small belts with too little tension.

    Agreed, I had the same problem with some early prints. Also I would check that the pulley on the motor is mounted correctly such that it's not rubbing on the motor or that the belt is rubbing on the frame.

  10. You will need to send the commands to the printer in order to change it. Editing the .gcode for a model will only change it when printing that model. There is a box in printrun on the lower right you can use to send individual commands to the printer. You will need to use M92 E to set the new E steps per mm and then send G92 to zero out the extrusion length.

    For example, if you have E steps of 865.888 (default), you extrude 50mm and measure 46mm. Then you want to set your new E steps to 941.183 and retest. First send the M92 to set the new E steps value, then G92 to zero out the extruded length.

    M92 E941.183 ;sets E steps per mm

    G92 E0 ;zero E axis

    Now you can retest and it should be very close to 50mm. If not, then you can change it again and repeat. Once you have the correct value then you should re-run the startup wizard in Cura and set the appropriate E steps, so that newly-generated gcode will have the correct values.

    One more thing to make sure is that your nozzle is primed for each test, else you will not get a fully accurate measurement.

    Also the M221 command as mentioned by Joergen (M2210 is just a typo I'm sure) will allow you to modify the extrusion speed by a % to correct, instead of changing the E steps. In your case I think you can just do M221 S109 to modify the extrusion speed by 109% (50/46 = 1.09 or 109%) which would give you the correct extrusion amount. But I haven't tried it this way personally. It should work, though. I do believe Marlin supports this M code but it's not clear from the reprap wiki.

    http://reprap.org/wiki/G-code#M221:_set ... percentage


  11. I did something dumb with 3 of my stepper drivers (plugged them in backwards... don't ask!) and pretty sure I fried them. The rest of the electronics seem fine, tested all 4 axis very carefully with the remaining stepper driver. So now I need replacements. I don't see them order-able on the UM store, but anyways I think I can get them a lot cheaper / less shipping here in the US. But the Pololu A4988 are sold out in a lot of places. I see there are some alternatives though and I'm wondering if any would be a better choice?

    Pololu DRV8825 (


    ) may be the most interesting thing. It supports 1/32 microstep and can sink 1.5A without active cooling. But it has some differences to the normal A4988 driver.

    SureStepr (


    ) - Can sink up to 1.2A and is a good price, but it doesn't support 1/8 microstepping, which the Z-axis uses. Can the Z axis work with 1/16? It's of course easy to change by setting the jumper on the Ultimaker electronics, but I'm not sure if there will be sufficient torque to drive the Z axis accurately at 1/16th. I can however simply use the 1 good ultistepper driver I have on the Z axis.

    StepStick / eBay A4988 drivers - Cheapest option. I read some of these are limited to 1A due to the sense resistor. Otherwise the same as the Pololu drivers.

    Pololu "Black" (


    ) same as the normal Pololu driver, just rated for a higher max current. More expensive.

  12. I also have some wood chipping in this area, and just had to clear a nozzle clog due to splinters getting carried through the bowden tube to the hot end. I am considering a guard made from shim stock to apply in this area, I haven't quite come up with a good solution to hold it in place just yet though.

    I also got the same wear groove in the delrin piece after maybe 1 kg of filament used, but now UM has upgraded their idler design to a Bertho-inspired design, so this shouldn't be a problem anymore.

  13. There was some mention of putting the extruder upgrade source files up somewhere but I haven't seen it.

    If you want to DIY one and don't want to wait for Ultimaker to release the design, you could use Bertho's extruder as a starting point. There are some differences but if you're going to adjust the Ultimaker version to use different bearings/springs then I'd expect you can also adjust Bertho's design.



  14. A good set of drill bits come in handy for clearing holes, with a pin vise or hand chuck to them them in. I have a set of number/letter drills which are "close enough" to most metric sized holes, but a set of metric drills would be better and cost less for the set. You could also pick up just the common sizes for cheap, you don't need fancy bits for hand drilling plastic.

  15. Printing snowygrouch's aluplate/peek cooling fanduct. Thank you very much for the STL.

    I think finally I have my Ultimaker almost perfectly tuned! :D

    edit: I would like to thank everyone here for the great information and help in getting an Ultimaker set up and troubleshooting the growing pains. :)


    large image:http://i.imgur.com/1j0xl.jpg

    small video:

  16. If you have good retraction you can try printing all the same sized gear parts as 1 plate, you can print many small parts faster that way as you don't hit the layer time minimum. And as the nozzle spends less time per part you solve this melted blob problem too. But if you don't have a well tuned machine with good retraction settings then you'll get strings. I think it's easier to fix those than this blob, though...

    Beware though the current version of Cura project planner has a bug and will crash your machine if you print 'layer at a time' instead of 'object at a time' or what's it called... You can just export a combined STL and slice it normally, or edit the gcode -- look for a Z0 move near the end and remove it.

  17. I'm also thinking about making my 2nd extrusion nozzle 0.8mm, this should enable faster printing at low resolution. However, it oozes a lot more.

    What if we went in reverse? What I'm seeing for most of the dual extruder setups, one would either be used for a support material or for a detailed part of the model. What if you used a .2mm nozzle? Then the support material wouldn't be at thick, thus easier to snap/dissolve off, the detailed section would be even more detailed, and we would lower oozing while it sat idle. Just a thought...

    It would take longer to print the support structure with a smaller nozzle size, and also more force to extrude 3mm filament -> .2mm nozzle.

  18. Yep, I used my calipers to measure the extrusion in a way I could rule out priming of the nozzle. First I set the caliper to ~70mm and put a piece of blue tape on the filament below the extruder. Next, close the caliper by 10mm and zero it. Now heat up the nozzle, and manually turn the feed wheel until the tape lines up with the caliper again. Extrude 50mm and check where the tape is, you should measure 50mm on the caliper. If not, then recalculate your E steps. 50/measured*e_steps = new_e_steps. So if you measured 47mm and had 825 e_steps, 50/47*825 = 877.6596, easy enough. You can do it with any length of filament you want, just change the numbers... I started with 20mm until I got close. But smaller lengths are hard to measure accurately.

    I used printrun, M92 and G92 to set the e steps and zero extrusion length, and extrusion button to push the filament.

    And don't forget to take the tape off else your extruder will eat it and jam... :(

  19. Check this out :


    Finally, almost perfect print. The Z scar is almost gone and sides are perfect, just a tiny ridge on the bottom but it is barely there. The light/dark banding effect is I think a very slight Z wobble, it is invisible when looking normally at the piece but when viewing light through the plastic it becomes visible. Some kind of diffraction perhaps, I am not sure... very interesting though!

    I changed just 2 things: I switched to Ultimachine PLA, and I re-calibrated my E steps per mm -- but this time I extruded through a heated nozzle. The value I measured from just pushing through the extruder was close to the default, but totally wrong through the nozzle! Finally with careful tweaking of the extruder tension knob I settled on 992 as a good value to get repeatable extrusion length. It seems odd I needed to increase so much from the default. I think the filament must be slipping slightly while extruding. If I adjust the extruder knob tension then I have to change the E steps again, which is troubling because if the filament diameter changes, it will be wrong.

    I see an extruder drive upgrade in my immediate future...

  20. Well, I suppose I don't want to argue about object design here, and I apologize for going offtopic. Lets ignore the shrinkage as it's truly not a "quality" issue anyways.

    Getting back to print quality, on larger prints I'm noticing a strange ripple or grooved effect on some objects. What could be causing this?


    Also in the 2nd image, the ridge along Z axis moves is visible along the upper edge.

  21. Question : how snug should these printable LM8UU bushings fit? I have precision ground 8mm rods, which measure within .01mm. I did a simple test to measure the force required to slide these on the smooth rod, and it is around 12-15kg which seems like WAY too much. I used a postal scale, and a quick jig made from wood blocks, so it's not the most accurate measurement. But they are very difficult to slide, even after working them quite a bit and spinning the rod with my drill for a bit.

    I could simply scale the part, but it's already specified at 8.1mm ID & 15mm OD, and I really think the Ultimaker should print this at a correct size. I realize that plastics shrink as it cools, but shouldn't this be taken into consideration by the slicing program?


    BTW, I printed this out at 1.02x scale in Cura, and now the OD is almost perfect (14.95-15.00mm) and the ID fits much smoother. Of course the length is now oversize by .5mm and I don't have any way to correct that in Cura. I can change the dimensions in the SCAD file and regenerate, but again it's the wrong way to fix inaccurate parts. From my days in the machine shop, we compensated for tool size and material properties. If we changed an end mill then we compensated for the tool size to get accurate cuts, we didn't go back and redraw the blueprints for the part to fit the tool. And if we changed the part material, we adjusted feed and speed to get accurate results.

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