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conny_g

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Posts posted by conny_g

  1. That makes sense! Thanks for your exhaustive input.
    I have not too much need to print beyond 250/260 degrees currently. It would not be worth on compromising on the non-stickiness.
    I was just looking for something universal that would cover higher temperatures and last long. But it seems the TFM / PTFE is already a reasonable compromise. So I think I'll remove the I2Ks and otherwise stay with the TFM/PTFE couplers.

  2. 10 hours ago, meduza said:

    I have a early generation I2K somewhere, i took it out because of too many feeding problems with PLA where it increased the feeding pressure quite a bit compared to the stock PTFE. PLA does stick a bit too well to PI for it being a one-stop solution for printing if you ever want to use PLA.

     

     

    I think this is an issue I am having, I have underextrusion issues lately and well posssible that this is the actual reason. Can't tell if the underextrusion happens mainly with PLA, but I am printing PLA 75% of the time. Though it was the nozzles in service for longer, but I should try to remove the I2Ks.
    The any other material than PTFE doesn't make sense if this is the only one PLA doesn't stick to. So in this case rather accept the wear than have underextrusion...

  3. 3 hours ago, foehnsturm said:

    same here, maybe below 110%. The above mentioned 105 were the minimum recommendation I think.

     

    Weird to say "glad to hear that". But the last few days printing a larger mechanical object (CO2 laser tube holder ?) the GreenTec was driving me crazy searching for the right print parameters. Good to see I am not alone ?
    I had checked the nozzle if it was clogged, the feeder if it grips and whatever else.
    And finally it's just soft for the feeder and of lower viscosity for the nozzle, pretty challenging combination.
     

    I researched this in the web and did not read a lot of these issues about it. Actually very little reviews / tests / experience with GreenTec. Makes the impression it's still low in reach in the community.
     

  4. 1 hour ago, foehnsturm said:

    Good point. As far as I can tell that makes the e.g. difference between GreenTec and regular PLA. The GreenTec seems to deform a little more on the drive gear due to the back pressure. I actually see a few percent less extruded than with other PLA at modest speed. Which matches the 105% flow setting you recommend for it

     

    I have quite some issues with GreenTec. I seem to have strong underextrusion with it. I print it with 115% flow, below that I have gaps in the print between perimeters and infill and sometimes even between perimeters.

  5. Hi all,

     

    I upgraded my 2nd UM2+ to Mark2 recently and had some issues initially. Took me some time to fix the hardware issues (Ultimaker mainboard blown, expansion board broken, nozzle jammed), calibration issues and now to find the right settings to get good dual print results. As it was a mix of things it was at times a bit difficult to understand what was happening.

    My first "cats" were really ugly and I took a few weeks (not full time, of course) to identify the issues and improve the print. I think I printed some 10-15 cats ?

    Here's the latest and best now, the best dual print cat I ever printed ?

    After some hardware issues the rest to tune and improve was print temperature, speed, acceleration, calibration.
     

    Temperature: with the 3DSolex Matchless nozzles I needed to go down to 180 C at 30mm/s print speed to get rid of overextrusion in small details and blobs. I think I never dared to print that low.


    Speed: at 30mm/s and lower (this cat was printed at about 25) seems to be the sweet spot.


    Acceleration: Interestingly this setting to control acceleration in Cura is really negative for prints with fine details. As the speed/acceleration goes down in the corners of small details, but the extrusion does not go down that fast it creates really bad edges and blobs. Best for this cat was to turn that Cura setting off and set the printer to 2.500/15 for acceleration/jerk.
    I was never looking here for an issue as this setting really improves prints with large straight areas and sharp corners. But obviously this is killing objects with small details.

    Calibration: I did the "dual meter" prints one complete evening calibrating the last fractions of millimeters, but still the cat print was off by 0.1-0.2mm. Still don't understand that, but with a few more cat prints, changing the extruder offset 0.05mm each time it got better and better. Also the Z-offset makes a big difference. Print first two layers in two colors and measure them with a caliper. Adjust Z-offest. Repeat until it's <=0.02mm accurate. Overall: it's worth to spend a few hours to a day on calibration, the prints will be much much better if you have fine details like this cat.

    See zoom photo attached on the "acceleration control" issue below.

    Hope this helps. I was quite mad and desperate in the middle of this process, really didn't understand why it was better with my first Mark2. But it's simply many parameters to get right and if you don't document them in detail....

    Cheers,
    Conny

    Pic of this best ever dual color cat print:

    yhkbMtR4Tw2GlorjJothgg.jpg

    Zoom image of the best cat, with accelaration control off.

    mmiTG5vBR1+TwWtaHxVdoQ.jpg

     

    Zoom image of one of the earlier tries with acceleration control on:
    (see the edges of the colors, terrible!)

    BU389Uv5SVKkJLShJqVU3A.jpg

     

  6. Hi all,

     

    can you tell if the newest Cura versions run fine with Mark2?

    Afair I have read that there were issues with the 3.x versions so I was not upgrading yet to save time & trouble.

    Have there been issues at all? Are they fixed? 

    I saw there is additional config files for Cura in the github package for Cura 3, is that all it needs?

     

    Cheers,
    Conny
     

  7. Recently I was wondering why of my freshly built Mark 2 printer the hotend fan and the model fan of the 2nd hotend won't work.

    Today I have taken the time to analyse it. Started by putting the printer to its side, opening the Mark 2 expansion board box and measuring the outputs of the board. Finding that there was no voltage on the fans. I noticed that the expansion board was rather hot on one side. My thermal imaging camera (flair one) said it was actually 80 degrees C hot. I saw it was the 1k resistor near the 6 pole header coming from the control panel board. Weird!

    So I unplugged the expansion board and took it to the desk to check what's wrong.

    Resistors were ok. One of the transistors had a short, the other at least no proper diode voltages. So it seemed the transistors were dead. But why?

    Umm. Shouldn't the diodes be the other way around if they are freewheeling diodes. Checked the schematic. Checked the diodes.

     

    Yes, they were mounted the wrong way!!

    I bought the board completed, so the manufacturer mounted the diodes the wrong way and that seems to have killed the transistors....

     

    So I reverted the diodes, mounted new BC817 transistors, reassembled the printer ... and ... it works, the fans are alive!


    @DidierKlein, who is assembling your boards? :-)

  8. 38 minutes ago, neotko said:

    I had two china clone boards, one was running for year and a half without issues. The only issue I had with them is that the fan/led molex plug was inverted (the plastic) other than that no issues. Can’t recommend a seller since the ones I bought from have removed the product 

     

    And how did the china board "end", by being replaced with Duet3D or did it fail? And the other one? :-)

     

  9. I have 2 UM2+ and three original boards, fried one two years ago. Unfortunately the repair of that failed. Changed the Atmega16u2 on that which works again now, but now the board has other issues (m2560 can be flashed directly, but not through USB and the board won’t start, display stays dark). Currently no time / enthusiasm to look further what the problem is.

     

    So I am actually considering of buying a chinese one as spare. It seems the frying of boards happens every 1-2 years :-)

    Which board or seller could you recommend?

    Any issues with the chinese I should be aware of or is it plug & play?

  10. Finally a first "two-color cat" with the freshly built Mark 2. The back is not very clean, forgot to switch on the "Mark 2 Tweaks".

    Disassembled the feeder, did not find anything unusual. 

    Found that I used an old version of the firmware, whyever I did that late in the night :-) Hope that's the reason for the E2 model fan not working.
    So I updated, reset the firmware, configured the parameters. Now calibrating and then another cat.

     

    fullsizeoutput_1cb1.jpeg

  11. 1 hour ago, neotko said:

    Check the small fan. It also has a transistor. Just in case...

     

    The hotend fan works. Also checked the transistor via diode test and it was ok.

     

    I have only two things open from this Mark 2 build and board repair: 

    - the E2 feeder (Bondtech) seems to have issues. E2 tends to underextrude and it makes decent strange clicking/crackling noises while extruding. But it does not grind. Interestingly I have swapped extruders for the dual mod (former E1 became E2) and that printer already had issues with the feeder before. So I should disassemble the feeder and see if there is something broken.

    - E2 model fan not working. Next steps: factory reset to make sure it’s not software. Double check firmware. Unplug and power the fan directly. Check expansion board connections. Check output signal of expansion board.

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