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12 heat bed's Marlin integration

Posted by rarprint 
12 heat bed's Marlin integration
May 15, 2017 04:34AM
Hi all!

I made prototype of fff 3d printer with build area 450 x 600 x 700 mm (XYZ). It have core XY kinematics. There are problem to find and make so big heat bed and i decide make it with 12 separate heat bed's (150x150 mm) each, see photo in attach. Also it give chance to heat only one small build area, not all heat bed.
See attach

Each heat bed platform have 12 Volt heater and temp sensor (thermistor 100k). To control this heaters i made schematics see photo below:

temp sensors do not show.

I need help[ with code for Marlin to make this:

1) Supporting 1-12 heat beds
2) Choosing temp and heating it up
3) View at display 12 heat beds real time state

Electronics is Arduino mega 2560, RAMPS 1.4, Rep Rap Full graphic display. I want make this project open to all and need your help
open | download - 12 segments heatbed.jpg (433.8 KB)
open | download - 1_heat_bed.jpg (24.9 KB)
open | download - 1_heat_bed_and_3mm_glass.jpg (27.5 KB)
open | download - 12_heat_beds_and_3mm_glass.jpg (42.8 KB)
open | download - zX7-aknisu8.jpg (428.9 KB)
open | download - r-7vFtkZ4FA.jpg (76.7 KB)
Re: 12 heat bed's Marlin integration
May 15, 2017 08:38AM

I suspect adding this many heated beds and thermistors would well and truly over whelm a pore little mega...
Also are there 12 free analog in's? I don’t think so... there are only 16 in total on a mega an most of those have been used as a digital out.
I also think your going to run out of spare IO lines, on a ramps...

I would have a separate mega controlling all the beds and their thermistors with a separate display and temperature setting knob.

I wouldn’t let the ramps know about the bed at all
Then you just need to wire a ramps io pin to the bed controller for basic on of.
use m42 to turn bed on and off in gcode.
Might need some feedback from bed for has reached temp...

latter add s serial line between the controller and bed controller, and some custom gcode to pass commands to the bed controler. forrmore direct control

Just curious how much current does each bed use?
Re: 12 heat bed's Marlin integration
May 15, 2017 09:18AM
Thank u for answer!

I think another arduino + Ramps for controlling heat beds are better. I shot little video of printing procces with 2 of 12 heat bed's : https://youtu.be/7d-dO_frRug

About current consumption: 12 Volt / 6 Ohm = 2 Amps It is for one heat bed. For 12 is 24 Amps. I have power 12 Volt 30 Amps = 360 Watt. It will be enuf
Re: 12 heat bed's Marlin integration
October 15, 2017 02:54PM
Hi all! Good news smiling smiley 12 heaters have control board for my big 3d printer GIGA

The decision is:
1) Main board is Arduino MEGA 2560 (because it's cheap and have 12 analog and 12 digital pins with PWM)
2) Display is Nextion HMI 7" (basic version), also cheap and easy to coding

I attach project files, may be it will be useful for somebody...

Programm code is not perfect it use Arduino Nextion library but working. Circuit board made in Diptrace software.


Edited 2 time(s). Last edit at 10/16/2017 04:38PM by rarprint.

RAR Print
Re: 12 heat bed's Marlin integration
October 18, 2017 10:16AM
Hi all!

Some testing doing today. Heating works fine, but to heat all 12 segments (150x150mm one segment) to 70 degrees, takes about 15-20min. After heating to target temperature all stable. I use 12 cartridge heaters 4.8 Ohm one. Power supply is 12 Volts 30A DC.

70 degrees target heating done smiling smiley Temp is stable.

Second photo

View from side to the prototype

12 segments heat bed with 4mm glass sheet (build plate size 450x600mm)

6 segments on and right 6 off

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