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Posts posted by error1

  1. I think a mechanical end stop switch sensor gives the most interesting options if it's accurate enough, more so than one that only detects metal. In theory you could resume some types of partial print by first calibrating the bed through the corners, then moving the Z axis to the bottom limit, center the head and move the Z upwards until the plastic part hits the calibration switch, probably repeat the calibration a couple times to get an average and then start skipping gcode until you get to the layer that corresponds to the measured Z height and start printing. It won't be perfect since the printer will most likely have rehomed all three axes so they have slight offsets, but it might be good enough.

    I gotta say that after all the upgrades the ultimaker is so reliable it doesn't really need a resume feature anyway, but it would sure be neat for those times when you ran out of plastic, or lost power, or some other accident happened :)

    Perhaps you could even glue flat plastic cases, books or whatever to your print bed, calibrate against them and engrave them with plastic ;)


  2. With a conductive aluminum bed, wouldn't it be possible to hack the top Z end stop switch and solder one lead to the print head nozzle and another to the bed so that it triggers if the two touch? I haven't checked to see if the heating element and temperature probe are galvanically isolated from the nozzle metal but i think they are...

    It would be a neat aid for leveling too! There would never be any question about where the absolute zero Z is :)

  3. I have the exact same issue with my ultimaker. I've gotten somewhat more reliable extruder operation from adjusting the bowden connection in the nozzle but it still likes to strip the filament in the middle of a really long important print :(

    I still haven't decided if excessive force on the thumbscrew is better than too little. Whenever i change filaments it takes three to four prints before i manage to dial it in to something that sort of works.... As far as i can tell this part could really need a redesign with two active rollers instead of the delrin friction drive!

    My goal now is to upgrade to the printable extruder by Geo Hagen, fingers crossed that it will make things reliable enough for long prints. It's really frustrating having to babysit the machine to keep a constant eye on the bowden tube, checking that the filament is still moving up through it at a steady rate... I have other things to do! :D

  4. OK, cool! I just realized i really need a dedicated printing station though. I just screwed up a three hour print because windows had turned off the monitor and replicatorG must have paused for a split second when i moved the mouse to turn the screen back on. Doh!

    Trying a laptop with linux, pronterface and every power saving option turned off now. It just finished yet another screwdriver, I'm going to have drawers full of these things by the time I finally get a reliable enough setup to print big parts :D

  5. Is there a trick to get the belts perfectly positioned? Now that you mention belts i think i have to readjust one of mine, even with lots of grease on the axis i can hear one of the brass bearings squeak a little when it moves across at a certain (slow) speed. I haven't had trouble with missed steps unless the nozzle rubs or crashes into the print but i figure any nasty movement noise means you're slowly wearing away at the metal and should be fixed as soon as possible...

    When i first did the adjustment I just loosened the pulley on each side and moved the head carriage back and forth several times until it the belt and pulleys slid into and stayed in the same position by themselves, then retightened the screws.

  6. I'd still say my extruder is "temperamental" at best, if i try to speed up above 100% things go haywire right away, with nasty stripped PLA getting fed into the bowden tube, and eventually it digs into the PLA enough that extrusion stops. If i leave it to do its thing at 100% speed though it manages to finish small parts fairly reliably.


    I'm starting to amass quite the collection of neat little screwdrivers :D

    How do you guys run your extruders? Tight or loose? I suppose i can try adjusting the thumbscrew REALLY tight tomorrow, i saw someone mention on the google group that they managed to set it up so that the stepper motor slips before the filament breaks.

    Oh and i'm printing this PLA at 200C, maybe that's simply too cold to go any faster. Maybe I'm biting off more than I can chew on my first week of 3d printing experience ;)

  7. OK, i went through the calibration steps here

    http://wiki.ultimaker.com/NetFabb_Setup ... d_versions

    but didn't really get any better results.

    I removed the hobbed bolt and cleaned it though, and tried feeding material through by hand while running the nozzle at 200C and it felt like it required suspiciously much force.

    Have a look at how the PEEK looks inside :(


    Album is here:


    Looks like even with the plumber tape and trying to make sure i had the bowden tube sticking out far enough from the carriage i still managed to screw it up.

    Now i just have to figure out how to get the temperature probe out of there and heat it up so i can clean it all out (but not enough to melt the PEEK).

  8. Hi! I've only had my ultimaker for a couple days, but i'm really struggling getting the right material feed rate, my extruder keeps trying to feed too much, building up pressure in the bowden tube and eventually stripping the PLA filament, ruining my prints when the flow stops. I'm unable to find the perfect sweet spot where i get good adhesion on the first layer and also enough flow through the nozzle to prevent a jam.

    I had hoped i could work around the problem by setting a really low feedrate for the Marlin firmware at the start of the print with for instance M92 E7 and then upping it to M92 E14 at layer 2 or 3 of the print when there's more distance from the print bed and better flow. Sadly, this just seems to halt the firmware.

    I bought NetFabb and is using that to generate gcode, then using replicatorG to send it to the printer and do live tuning. Is there a way to tell netfabb that it should slow down the feed rate at the beginning?

    I'm also trying to print


    hoping that it will help a little, but really what i think is required is an adjustable friction clutch for the extruder, so that it slips on that instead of damaging or stripping the filament (since once the filament is stripped, it usually won't start extruding again without a lot of help and it's better to pull out the filament and cut off the broken piece)

    ...Or maybe it's possible to adjust the stepper driver for the extruder to force it to slip steps? Has anyone tried that?

  9. Instead of a stepper, why not some sort of valve on the nozzle that can be quickly closed and opened?

    I'm still waiting for my ultimaker kit to be shipped so i'm not really familiar with the mechanism, but it makes more sense to me to leave the main feeding mechanism where it is and add a small solenoid or servo to the print head that could either block the nozzle with a tiny metal pin or maybe even operate some sort of scissor or knife mechanism to cut the plastic string at the start of a fast jump.

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