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bed heater upgrade?

Discussion in 'General Questions' started by BossHoss, May 15, 2016.

  1. BossHoss

    BossHoss New Member

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    I was wondering if anyone had a source for a better heating element for the bed. I've got seriously varied temperatures, and its playing hell on a lot of my prints. Some of the spots are 10 degrees cooler than most of the bed when measured via IR at 60 degree bed temp setting. Before i get asked, yes this is all within the area of the heating element. Off element readings are closer to 20+ degrees low. I only have about 4" x 5 1/2" of consistent heating. Basically I only have usable heat from the top of the "R" down to the top of the heat warning squares on the Y axis, and from the insides of the heat warning squares across the X axis. I've played around with the element making sure it contacts the plate well in the places it runs cool, checked wires and connections to make sure there are no issues, but the results don't change. I'm not opposed to swapping the bed, but I'd prefer to find a better, more consistent heating element, since that's where my issue seems to be.
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You might be better off going for a higher wattage one not powered off of the RAMPS and internal Power Supply.
    You can use a relay to power it (RAMPS opens/closes the relay to drive it).
     
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  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    About the only thing I print that needs a high-temp heat anymore is polycarb and the built in heater will do it, just slowly.
    Nothing else we use is that sensitive to bed heat.
     
  4. BossHoss

    BossHoss New Member

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    Thanks for the tip. The wiring is something i can handle, but could you point me in the direction of a higher wattage element? I did a little searching last night, but I don't really know what wattage I should be looking at. Once i have that figured, it shouldn't be a big deal to decide on an adequate power supply.
     
  5. BossHoss

    BossHoss New Member

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    I dont need super high temps, but all of my prints whether they're PLA, ABS, or PETG have issues sticking behind the robo "R". i've got my speeds kicked down pretty low to combat a little of the inertia from the print head. I know I could be printing the PLA without bed heat, but I have great results even with some of the shadier quality PLAs as long as i keep it away from the dead spots, but the PETG and ABS still need some bed heat.
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    For the one powered by the RAMPS it is 12v, 11a max.

    Call that 130w, If you powered the heater from 24v (it can take that) then it becomes 260w :)
    Just isolate the 24v to power only the bed heater. Not only hotter, but way faster to get there.

    We never 'need' ABS any longer since there is always something with better specs that prints easier :)
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    In fact if you shop around for bed heaters you will see most are rated for 12 or 24 volts.
     
  8. BossHoss

    BossHoss New Member

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    Now, I understand that doubling the source voltage is going to double my wattage, but I'm not exactly clear on how upping my wattage service is going to help combat the dead spots. Faster and hotter are both great attributes, but it seems to me that my issue is possibly rooted in the design of the element itself. I could be wrong, but it just appears that certain spots generate heat better than others. Im no electrical engineer or anything, but what I was thinking was maybe a different resistance wire configuration in the element might be the solution. As for the ABS, I don't print in ABS often, but there are a few aesthetic prints i do where the vapor smoothing is really beneficial to the final product. The bulk of my prints are PLA, followed by PETG.
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The only point to increasing the wattage (the voltage) is to make the entire heater work harder.
    If the spots truly are dead then nothing will fix that. If they are just weaker then upping the wattage will generate more heat.
    You can find lots of replacement heater beds on Amazon. the silicon pad style will work better in terms of generating a more even pattern of heat than the style that Robo uses (the cheaper ones).
     
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  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    vapor polishing is the only feature ABS has that isn't reproducible with something else (in terms of filament). You can achieve the same result with coatings (like XTC-3D) but not with any other material directly.
     
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  11. WZ9V

    WZ9V Active Member

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    I'm still waiting for it but I am getting a custom Silicone pad heater I plan to run off of 120V 3A via a DC/AC SSR. When I get it all hooked up I'll report back. I'm also ditching the glass plate for some tooling aluminum.
     
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  12. BossHoss

    BossHoss New Member

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    Ok, that's what I think i was looking for. The weak spots vs. dead spots part is what i was missing from the earlier post. I'm more inclined to believe I have weaker spots in the element based on the fact that there's still a substantial gap between the areas in question and the off element areas i measured. If they were truly dead, I'd probably be getting readings closer to 15 or 20 degrees below the target temp.

    I'm really curious how that ends up working. I did manage to find a couple of 200mm x 200mm silicone pads, but they looked a little questionable. Maybe I'm just being paranoid about putting a heating element from a chinese company I've never heard of into an important piece of equipment, but I'll typically err to the side of caution when there's a fire hazard involved. I'll keep an eye out for your results.

    Thanks for the replies
     
  13. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    One thing that might be contributing is that the pad you have may be sectioned and where the two mate there might be a gap.

    There are a lot of options... a thin aluminum plate on top will help distribute the heat more evenly if you really need it.
     
  14. WZ9V

    WZ9V Active Member

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    @BossHoss, probably a wise choice. I know some people who have used this supplier without problem otherwise I'd consider it pretty risky also.
     
  15. Gregg Teaby

    Gregg Teaby New Member

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    You don't have to upgrade your bed heater. This is what I did. I removed the two bolts under the print bed for the y axis. They have a hex head on them. I machine about .150 off of the hex heads then reinstalled them. Next, you will need a roll of 1/8 cork, you can buy this from Lowes for 10 bucks. Cut a piece of cork as large as will fit. Tape it in place right on top of the 1/16 thick cork that comes with the RoBo. I use the silver aluminum tape. When you put the bed back on and preheat the bed you will be very happy. I use my IR temp meter to take readings. I have a new stock heater element. It is a very nice kapton heater.


    Sent from my iPad using Tapatalk
     

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