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  1. #71
    Staff Engineer printbus's Avatar
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    May 2014
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    Highlands Ranch, Colorado USA
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    Add printbus on Thingiverse
    Quote Originally Posted by razer1141 View Post
    ...I've noticed my prints aren't as tall as they should be, but the other dimensions are pretty close to correct.
    Are they compressed or cut off? If compressed, what values are you using for DEFAULT_STEPS_PER_UNIT in configuration.h? Another thing to check would be to make sure the tubing shaft couplers on the Z motors aren't slipping.

    Quote Originally Posted by sniffle View Post
    btw printbus, takes between 3-5 min for my 12" bed to hit 110 degrees. using 12AWG wire and 1 layer of cardboard underneath
    Quote Originally Posted by pichuete View Post
    i bought a 12v "30a" power supply from amazon one of those "Cheap" Chinese LED Power supply . and it only lasted 1 print. after that i put my RC charger power supply which is a 350w 12v and the power outlets where melting after 2 hours of use .
    FWIW, both of these posts suggest the heat bed on the 12-inch printer draws a LOT of current. More than just the linear increase expected due to the increase in heater area.

  2. #72
    Interesting I have not had this issue with my heat bed yet. The power supply I use http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1
    Which i had used in the past for LED lighting display that had a couple thousand leds and is UL certified. The fan on the power supply has not kicked in yet. I am also using a aluminum bed which has a higher thermal conductivity then glass but the close to the same heat capacity as glass.
    Last edited by bstag; 12-23-2014 at 11:53 AM.

  3. #73
    Quote Originally Posted by printbus View Post
    Are they compressed or cut off? If compressed, what values are you using for DEFAULT_STEPS_PER_UNIT in configuration.h? Another thing to check would be to make sure the tubing shaft couplers on the Z motors aren't slipping.





    FWIW, both of these posts suggest the heat bed on the 12-inch printer draws a LOT of current. More than just the linear increase expected due to the increase in heater area.
    Thanks for the information. The prints are compressed. I'm not sure what the default steps per unit is set to. I know I haven't changed it, but I will check and see what is set. I'll try to mark the tubing/rail/shaft with a sharpie and see if it is slipping. I did order a couple of metal couplers a while back, but the ones I wanted I could only find shipped from amazon, so I think I have a week or two before I see those.

    As for the PSU/Heatbed, I also ordered a 12v 30a LED power supply for ~$25 from amazon and Ihaven't had any issues. I'm using corkboard as insulation and it does take a couple of minutes to warm up, but I haven't timed it. I will try to remember to do that. I used Fork Crimp terminals on the wires attached to the PSU if that makes a difference.

  4. #74
    Technician
    Join Date
    Nov 2014
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    58
    I'm pretty sure I got a bad PSU to start with. From the beginning it sounded like it was going to explode. I will measure the overall current when my new PSU arrive. I'm guessing that the consumption is pretty close to 30 amps when the bed and extruder are on.

    I bought a 12v 75 amps server PSU to be in the safe side. Most of the big 3d printers use 24v..

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