24V power supply SRS / relais extension box for 3d printer

thingiverse

I created a box to house an external 24-volt power supply. My 3D printer used to get 12 volts from the motherboard to its heating element, taking about twenty minutes to reach 100 degrees Celsius after insulating it with some material on top. The temperature would fluctuate significantly afterwards. The printer's original design made no room for an additional power supply, so I kept the 24-volt supply outside the printer's housing but only connected one cable to it. This box contains a solid-state relay, heatsink, and fan. The solid-state relay can be installed either at the top or bottom of its hole. A single cable links these components together and includes signals for: 220V AC mains AC mains earth 12-volt direct current to power the relay "12-volt direct current" earth 24-volt direct current to heatbed "24-volt direct current" earth The fan within the box gets its power from the 12 volts already supplied by the external power supply. This power supply, connected behind the printer's on/off switch, turns itself off when the printer is powered down. **IMPORTANT NOTE:** My initial setup using a solid-state relay did not work out well at all. With PID settings set in Marlin to control the heatbed, along with a fan and heatsink attached to it, the whole setup ended up melting down. Replacing the relay with a 30-amp car fuse, I changed Marlin's heating bed controller to the bang-bang method to prevent rapid switching on the relay. With this adjustment in place, things started working properly immediately! With my modifications now operational, it only takes about five minutes for my heatbed to reach its maximum temperature of 100 degrees Celsius – and remains steady at that level. Even at temperatures as high as 120 degrees Celsius, it shows remarkable stability. Keep in mind my heating element can run either at twelve volts or twenty-four depending on the setup. My original 12-volt heatbed required insulation before it reached the 100-degree mark. With a single configuration tweak allowing it to work with the twenty-four volts power supplied by the relay instead of its built-in twelve volts, my overall heatbed control issue got fixed.