Bed heating

[Pappy3831]

After a long hiatus I’m back to building my 2.4. In the process, I ordered an LDO 250 trident kit. I’m a glutton for punishment. And I’ve watched too many build videos. 
 

back to the subject.  Thinking of getting the mandala ultra flat bed for the 2.4. The question is does getting a heater that goes almost edge to edge be beneficial to a more even bed plate heating?

[mvdveer]

1 hour ago, Pappy3831 said:

The question is does getting a heater that goes almost edge to edge be beneficial to a more even bed plate heating?

Always will be. Also cuts of time in soaking the bed to allow for thermal expansion. 

[Pappy3831]

Thank you sir. Just wanted to make sure before I spent more money

[YaaJ]

According to the Voron Team, power should be limited to 0.4W/cm². Has to do with warping.
This is something I don't understand... Shouldn't it be calculated from a volume ?

As a result, the max PWM has to be limited in Klipper. Same with the 0.2. 60% ; takes too long to heat up, set it to 80%, no problems sor far.
"Stock" Voron 2.4 bed is 8mm thick. LDO one is 10mm thick. 25% more. Just verrified.

Here's a calculator :

https://tools.takuya.wtf/Calculator.html

Also read on Voron forum or Reddit that this rule of thumb is obsolete, but no explanations...

Some thoughts ?

(we even could imagine something progessive ; progressively delivering more and more power, depending on the temperature)