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Printing at wrong height & other problems

Discussion in 'Troubleshooting' started by Jimwahhh, Jan 25, 2014.

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  1. Mike Kelly

    Mike Kelly Volunteer

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    this is with the relay? How hot is your relay getting.

    You might switch to bang bang, or get a heatsink for it.
     
    #21 Mike Kelly, Jan 27, 2014
  2. Jimwahhh

    Jimwahhh Member

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    Mine is rated to 100A and doesn't get hot at all. I don't know enough about electronics to know whether it being so over rated is an issue.
     
    #22 Jimwahhh, Jan 27, 2014
  3. Ziggy

    Ziggy Moderator
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    The firmware that came with the Robo shipment late 2013 is already set to bang-bang for the bed heater.
     
    #23 Ziggy, Jan 27, 2014
  4. Jimwahhh

    Jimwahhh Member

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    Just took this screenshot that shows what is happening pretty well. Looks like it is about the 4th layer that the temp drops off and the output to the heat bed goes to 100%. Before that point it didn't look like it was struggling at all.

    Weird.
     

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    #24 Jimwahhh, Jan 27, 2014
  5. Ziggy

    Ziggy Moderator
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    Everything points to some issue with the power supply. But need both voltage and current measurements to identify the root cause.
     
    #25 Ziggy, Jan 28, 2014
  6. Ziggy

    Ziggy Moderator
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    Mike,

    The screenshot shows the result of a simple manual test.

    1) The bed, extruder and cooling fan were switched on manually. Bed was set to 100c, Extruder to 210c and cooling fan 100%. Nothing else was running.

    As you can see from the temperature plot, the bed held temperature for less than 5 mins then started to drop about 10c.

    2) At the 50min mark on the plot the extruder and fan were manually turned off.

    The bed temperature then immediately started to recover and got back to 100c and held.

    3) Just to be sure I turned the extruder and cooling fan back on again.

    The bed temperature immediately started to drop again to about 90c.

    4) I manually turned the extruder and fan off again about 15mins later.

    Bed temperature again immediately started to recover to 100c and held


    Can you please ask the Robo technical guys to take a look at this (I assume you have contacts there?). Looks like there is an issue with the power supply not handling the full load of bed, extruder and fan.

    The power supply rating appears to be 30A. But there are three dc outlets (sets of terminals) from the PS. It's not clear whether all outlets are tied together internally or there are actually 3 x 10A separate outlets.

    Also. I went looking for the Power Supply fan because I could hear it running flat out. I can see the fan through a grille inside the Robo housing. But most of the fan outlet is actually closed off by the grille on the Robo housing. If the PS is not being cooled properly then that could explain the problem. If I could get the PS out I would try it with better cooling. But it is jammed in and will not move!!

    Z
     

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    #26 Ziggy, Jan 28, 2014
  7. Jimwahhh

    Jimwahhh Member

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    Yup, that does make a lot of sense. And the reason it happens for me after a few layers is because the speed of all the motors is lower for the first layers. Again I'm pretty disappointed about the Robo3D, this seems like a pretty fundamental design flaw with the electronics, as if having to install a relay on the second day of having the printer wasn't enough.
     
    #27 Jimwahhh, Jan 28, 2014
  8. tompeel1

    tompeel1 New Member

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    Yep your last paragraph was the unheard argument I hadn't heard! I'm in! Color not such a priblem for me.

    As fire the fan what your saying removes the "hot" and "cold" heat sinks becaus they are not in series?

    Sorry just caught up on the whole thread... might be telling you to stuck eggs!
     
    #28 tompeel1, Jan 28, 2014
  9. Jerry RoBo 3D

    Jerry RoBo 3D Administrator
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    I'm very certain that the issue you are discussing is actually the problem with the Polyswitch at location F2. This switch will turn the current to the bed off if the air around the switch gets to 40C. The design flaw was mounting the arduino to the roof of the bottom case, making a bit of a heat trap. This problem is very easily solved with a fan. Please see this post: http://forums.robo3dprinter.com/ind...t-heat-bed-cutting-out.1299/page-3#post-12186

    The power supply is rated for 30 amps at 12 volts. At most our components need 16 amps. If you are having trouble with your bed cutting out, please email me at robo3dhelp@gmail.com and I will send you a fan in the mail for free.
     
    #29 Jerry RoBo 3D, Jan 28, 2014
  10. Jimwahhh

    Jimwahhh Member

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    Jerry the problem is that the Heat bed is NOT TURNING OFF. As stated a fair few times in this thread, the heat bed is still on, but it's temperature just drops to around 80-90C. As far as I am aware the issues with polyfuses (which I have had to install a relay to overcome already) causes the bed to drop to ambient, not only drop the 10-20C to level out at a lower temp.
     
    #30 Jimwahhh, Jan 28, 2014
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Not always, but yes... often. Add a fan.
    If it is the polyfuse this will sort it.
     
    #31 mark tomlinson, Jan 28, 2014
  12. Jimwahhh

    Jimwahhh Member

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    Just frustrating as I have already added the relay to try to sort out this screw up. I was not aware that a fuse could just throttle the current.
     
    #32 Jimwahhh, Jan 28, 2014
  13. Ziggy

    Ziggy Moderator
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    Jerry,

    It is NOT the polyfuse. Please take a close look at exactly what is happening with the power supply, heated bed, extruder and fan as described in my post above.

    In my case I have shorted out the polyfuse (as a temporay measure) so it is no longer in the circuit. Others with this power supply problem have already installed the solid state relay. Let me say again - the polyfuse is not the problem in this case!

    Z
     
    #33 Ziggy, Jan 28, 2014
  14. Jerry RoBo 3D

    Jerry RoBo 3D Administrator
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    Jimwahh, Ziggy,

    Sorry, I spoke to soon. You guys aren't having a polyswitch issue. It couldn't be a power supply issue unless your specific power supplies are somehow defective. Certainly not a design flaw. As stated above, the power supply can supply 30 amps.

    So basically either your power supplies need to eat their wheaties, or Repetier is saying it's doing one thing, but doing the opposite instead.

    Lets rule Repetier out. Please try using Matter Control to run a print. Here's the download:

    https://mattercontrol.appspot.com/downloads/mattercontrol-robo3d-windows/release
    https://mattercontrol.appspot.com/downloads/mattercontrol-robo3d-mac-os-x/release
    http://www.matterhackers.com/articles/mattercontrol-getting-started
    Let us know what you find out.
    Sorry you are having this trouble.
     
    #34 Jerry RoBo 3D, Jan 28, 2014
  15. Ziggy

    Ziggy Moderator
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    Jerry,

    Thanks for responding to this issue.

    I am very willing to help get to the root cause and fix it. Will check out Matter Control and get back.

    I am sure Repetier is doing what it is saying it is doing. I can see the power being applied to the bed on my meter and scope.However let's see what Matter Control does.

    I have emailed you separately re what I think is the root cause. Power Supply doesn't need to eat it's wheaties - just needs lots more fresh air.

    Z
     
    #35 Ziggy, Jan 28, 2014
  16. Jimwahhh

    Jimwahhh Member

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    Hi Jerry,

    Thanks for checking this out. I can try to find time to check Matter Control tonight but I suspect Ziggy will probably beat me to it.

    Perhaps we might need to take a dremel to the robo to give the PS some breathing space Ziggy?
     
    #36 Jimwahhh, Jan 28, 2014
  17. Ziggy

    Ziggy Moderator
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    Hi Jerry

    I noticed this photo on another post. Is this the correct way to install the power supply? If it is, then mine has been installed upside down!!

    Having the PS fan open like this would help keep the PS cooler than with the restricted airflow through the grill inside the housing.

    Z
     

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    #37 Ziggy, Jan 28, 2014
  18. Jimwahhh

    Jimwahhh Member

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    I can't really see because that picture is tiny, but if you are talking about having it upside down then that can't be right can it? Wouldn't that mean that the switch to change from 110-240V would be on the wrong side?
     
    #38 Jimwahhh, Jan 29, 2014
  19. Ziggy

    Ziggy Moderator
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    duhhh.. Of course you are right. The PS in the tiny picture must be a different brand or different design.

    Z
     
    #39 Ziggy, Jan 29, 2014
  20. Ziggy

    Ziggy Moderator
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    Hi Jerry

    The screenshot shows the result of a test I did with Matter Control

    Ambient temp was around 24-25c.

    I manually turned on the heated bed (set to 100c), the extruder (set to 220c) and the fan (set to 255 = full on). The extruder was positioned over the centre of the bed. There was no print running, but I just moved the extruder around a couple of millimeters a few times.

    The bed reached temperature and held for about 8 mins. Then the bed temperature slowly dropped off to around 87-88c and stayed there. The screen shot shows the bed at 87.4c versus the target temperature of 100c.

    When I turned the extruder and fan off, the bed temperature recovered back to 100c.

    This behaviour was all the same as I had reported earlier with Repetier.

    Z
     

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    #40 Ziggy, Jan 29, 2014
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