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Answered Bad heated bed?

Discussion in 'Troubleshooting' started by David Carter, Feb 6, 2017.

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  1. David Carter

    David Carter Member

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    Hello all!

    After many struggles, I finally got my printer printing, but now I'm facing another problem.

    I start the print. I watch the first few layers lay down successfully. When I come back a little later, the print is peeling off of the bed. I raised the bed temperature from 50 to 55 (printing PLA), and it's better but it doesn't go away.

    Checking with my hands, I notice it's definitely hotter on one end of the bed than on the other.

    I was trying to print 4 of these together

    IMG_1753.JPG

    Two were mangled and pulled by the extruder off of the bed

    IMG_1745.JPG

    The next large pieces I printed were also peeling off

    IMG_1754.JPG

    I changed the orientation so they were on a slightly different area of the bed. The colder end lifted as expected.

    IMG_1755.JPG

    What they're supposed to look like:

    IMG_1743.JPG
     
    #1 David Carter, Feb 6, 2017
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    With the type of heater the R1/R1+ uses this is not an unheard of problem.

    You can see a fairly large temperature variation on the out regions of the printable area.
    There are a few things you can do (one of which is to replace/upgrade the bed heater and there is at least one or two threads on this in the Projects sub-forum). Arranging the prints to suit the heated area is another option. My suggestion is to use the minimal amount o heat possible. Warping of filament is either bad filament (seldom) or temperature management issues (normal). IN the case of ABS you could argue it a bit of both :) I have had at least a couple of spools (out of many, many, many others) that were junk and would warp for no apparent reason.

    For PLA (in theory) room temperature is fine for the bed. In practice Your Mileage May Vary. I am able to print PLA on the Robos with only a slight amount of heat (40c normally) but on the delta printer we have I have to go at least 55-60c or it will pop loose. You can use chemical "boosters" to assist in that adhesion. For PLA we use WolfBite Nano (I always use this on the delta, never on the Robo).

    If you want help pursuing a replacement heater we can assist--out of warranty obviously since under warranty you should be taking that complaint straight to Robo3D. I am not sure what they will do with that in a warranty claim, but if the heated area is significantly off from their spec they should replace it.
     
    #2 mark tomlinson, Feb 7, 2017
  3. David Carter

    David Carter Member

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    Well, I tried lowering the bed temp to 40. An hour in to a four hour print and things look ok so far. I'll update when the print is finished.

    So assuming this is a short term workaround, I still want the bed problem corrected. Before I look at replacing, is there anything I should check in terms of cables, connectors, voltages, etc? I did a quick visual inspection and saw no issues.
     
    #3 David Carter, Feb 7, 2017
  4. daniel871

    daniel871 Well-Known Member

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    There is no short term workaround, the heating element is comically undersized for the advertised print area.

    Your real options are to modify the printer per one of the bed heater projects in that sub-forum.

    I suppose it might be possible to workaround if you buy something like the ZebraSkin product and apply it to the bed and rely on that to hold your print, and just adjust your Starting GCode in the slicer so as not to melt the covering on the bed.

    Maybe a sheet of LokBuild? That one just came out and holds a lot of promise as well.
     
    #4 daniel871, Feb 7, 2017
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You can check the RAMPS board connections where the heated bed comes off and see if they look good. Sometimes the MOSET driving that will fail and the connactors will show signs of "distress" (look blackened or burnt).
     
    #5 mark tomlinson, Feb 7, 2017
  6. David Carter

    David Carter Member

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    Are there multiple MOSFETs? One side of the element seems to be warm while the other is not
     
    #6 David Carter, Feb 7, 2017
  7. daniel871

    daniel871 Well-Known Member

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    Nope. If the element is only partially heating then the element is bad.
     
    #7 daniel871, Feb 7, 2017
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    There are multiple MOSFETS on the RAMPS, but only one for the bed heater.
    On the standard RAMPS that is Q3.
     
    #8 mark tomlinson, Feb 7, 2017
  9. David Carter

    David Carter Member

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    Well, the workaround is insufficient. It's almost ok, but just bad enough to make the part useless. I guess I need to replace.

    So what's the method here? Replace just the element or the entire bed?
     
    #9 David Carter, Feb 7, 2017
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Under warranty get on the horn with Robo and get a new bed.
    Out of warranty you can buy another heater. I would suggest NOT getting the same style, but rather getting one elsewhere.
    Look for a 12v 150w 3d printer bed heater and find the size you like best. If you want to now might be a good time to swap to using a solid state relay to drive the bed heater rather than having the RAMPS do it. There is at least one thread on this you can refer to.
     
    #10 mark tomlinson, Feb 7, 2017
  11. David Carter

    David Carter Member

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    Ok, I'm marking this as answered. I've ordered a replacement heater, SSR, and upgraded power supply. The heater will take a while to get here, and I'm about to leave on an extended business trip. I'll start an upgrade thread when I return.

    Thanks for the help!
     
    #11 David Carter, Feb 7, 2017
    mark tomlinson likes this.
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