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Heated bed upgrade for D-bot Core XY

Posted by jmichaelland 
Heated bed upgrade for D-bot Core XY
January 13, 2018 08:11PM
I have built the D-bot printer and have been extremely happy with all of the results so far, all parts are almost identical to the BOM from spauda01. I am having trouble printing ABS though so i am planning to upgrade my MK2a PCB heated bed for a silicone mat. I am fairly new to electronics so please bare with me. My questions are....

1. Which heated mat should i purchase my build surface is 200x300(open for any suggestions)
2. I have a SSR that is rated for 40A DC - DC that works perfectly with the PCB board right now aside from maintaining 100 C, will this be okay just to hook a more powerful heated bed to the same DC-DC SSR the same way the PCB is wired? (Wired according the d-bot wiring diagram)
3. Would a better route to buy a MOFSET? and would i replace the SSR with the MOFSET or have them both.
4. Does anyone know of any wiring diagrams for either of these options that they could share with me

Electrical Diagram Link here : [cdn.thingiverse.com]

Sorry for the very newbie questions smiling smiley


Re: Heated bed upgrade for D-bot Core XY
January 14, 2018 03:03AM
What make/model of SSR is it, and what is the voltage drop across it when the bed heater is on at full power? You have a few options depending on the answer:

1. If it's a so-called Fotek SSR-40DD then you will get 1 to 2V drop across it which will reduce the bed heating power substantially. A side effect is that the SSR will be getting very hot. In this case, you should replace the SSR by the Auber Instruments one or by a mosfet board. This will increase the bed heating power by 20% or more.

2. You can turn up the voltage on your PSU to 14V if it has sufficient power reserve. The snag is that you risk overheating the 5V regulator on the Arduino, unless you take precautions against this.

3. If you choose to get a silicone heater instead, I recommend a power density of 0.4W per square cm. So that's 240W for a 300 x 200mm bed.

Edited 1 time(s). Last edit at 01/14/2018 03:27AM by dc42.

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: Heated bed upgrade for D-bot Core XY
January 14, 2018 03:06AM
I got my 300x200 silicone mat from robotdigg, but they didn't state any wattage. It was only 100W in the 24V version. A bit slow for ABS. I have to run it with 28V to raise the wattage. Maybe the 12V version has more power?
The DCDC SSR is good enough, no need to buy a MOSFET ( which is practically the same in a different package )
Re: Heated bed upgrade for D-bot Core XY
January 14, 2018 09:29AM
Thanks for the fast reply!

1. It is in fact a FOTEK SSR but i believe it is genuine, I've picked it up from a big box electronic store and i have never noticed any overheating. Its not even very warm to the touch when in operation.

2. My PSU does give me the option to increase the output voltage by 10% but i am by no means a expect electrician and have no idea what precautions will i need to take to avoid ruining the Ardunio. If its a simple process i may consider this option.

3.Will this silicone heated mat be sufficient to just swap out with my current PCB considering the specs of my printer?

Thanks again

Re: Heated bed upgrade for D-bot Core XY
January 14, 2018 09:30AM
Awesome thanks for the clarification o_lampe
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