Using just the standard designed RAMPS board you're limited at 11 amps for the heated bed and 5 amps for everything else. The heated bed can be ran at 24v which either divides the needed current in half for the same power, or doubles the available power at the same current enabling a larger area to be heated. Beyond typical needs, the output could be used to control a relay (solid state or even just mechanical) to switch even higher current or mains voltage.Quote
Natas70
So there is no amp load limitation? I have seen people talk about the Ramps board cannot handle a larger heated bed than about a 8". Is this a totally different situation, to me it seems to be the same condition, thermistor and heating element of some sort. and not necessarily the ramps board itself but the arduino/ramps combination.
For the hot end, the typical 40w cartridge heater (12v @ 3-1/3 amps) can easily get to 300 or 350 degrees. It may require some type of insulation around the heater block to keep the heat in and not let it serve as a heat sink at higher temperatures. Consider your typical 12w soldering iron, 1/3 the power of the cartridge heater. They can easily get to 400 degrees C at the tip. They may not be able to heat something that hot once the heat starts being drawn away, but that's where the larger capacity (and possibly insulation) comes into play.
