Automatic Power Off after print V2 - low voltage version

myminifactory

Hi! How about automatic powering off your printer when printing is done? This is a new, upgraded version of my project. https://www.thingiverse.com/thing:3333899/ This one is low voltage, much safer for the user. I recommend making this one. I want to share my upgrade for 3D printers that gives Auto Power Off functionality. Some printers equipped with ATX PSU can do this by simple M81 command. Lucky owners! All others know these timers to switch off the printer after printing is finished. We also know that expected finishing time may be different than calculated by slicer software. So we add one or two hours to not switch off the printer too early. I started to get tired of this solution and invented my way of secure switching off the printer just after the printing. Tested with Ender 3. It should work with similar printers. After finishing, the printer cools down and raises the printhead frame to the maximum height. It triggers a switch and disconnects power from the printer. What do you need to upgrade your printer? Most importantly, know how to work with potentially lethal live voltage. You will not need to take a risk, but mistakes can always happen!!! So please, ask a professional to help you with cabling. About 1/2 meter of two-wire cable, 2 x 1mm2 at least. Soldering irons, soldering skills (not advanced), some insulating tape or thermoshrink tubes, two screws for fixing to the frame, and I had hammer nuts (T-nuts) with 4x14 screws. Two screws with nuts to fix microswitch. Mine are 2x12mm but it's not so important. A microswitch with a lever, any current. Mine is 5A (size 20x10mm distance between the holes 9.5mm). It's also a good idea to use small switches like used for XYZ stops (you may have one free after installing BLTouch or 3DTouch). A 24V DC relay (12V if your printer is 12V) capable of taking 20Amps or more. Current on the low voltage part is high, 15-20Amps. It may also be an electronic relay, quite common nowadays. Some time :-) Assembly instruction: Print V2 arm. PLA or any other material except for TPU. Fancy color is highly recommended! 20% infill. Layer 0.2mm is okay. No supports. No rafts. No brim. V1 arm is fine too, but there's a risk of collision with some models of the head in very rare cases of high and wide prints. Prepare all parts. Power off the printer. Unplug the power cable! Disconnect the low voltage connector (2 wires). Unscrew the PSU from the frame. Remove the plastic cover of the PSU cables. Make connections as shown on the schematic. Solder them securely. Secure connections with tubes or insulating tape. Important! Secure also the third, not used pin of microswitch. It may have voltage when the printer is turned off by the switch. You are done with electro-mechanics. Now it's time for software and adjusting. Add "special" commands to the end sequence in your slicer (i.e. Cura--Settings--Printer--Manage Printers--Machine Settings--End G-Code window). Disable M84 command with ";" G4 S300 ; wait 5mins to cool nozzle G0 Z250 ; go up to max height You may adapt commands to your needs. Decrease Z250 part if your printer is smaller than Ender3 which has 250mm max height. 5min pause is really needed. Too much heat from the hot nozzle without cooling fan active may cause filament jamming in the head. Print anything. Small one for sure. Wait until the frame goes up. Use of terminal is also okay. Octoprint or any other one. Just send commands: G28 G0 Z250 Adjust printed arm with microswitch to trigger it. It should power off your printer! You are done!!! Congratulations. No more power waste. You are GREEN now! Starting the printer is simply by pushing the frame little down. Power is coming back. In case of another microswitch, you may adapt holes in the arm or ask me for help with it. STP files enclosed Good luck and happy printing! ------------------------------------------------------------------- Power consumption measured just now by curiosity (with Octopi powered from Ender's PSU): system idle: 11W nozzle heating: 56W bed heating: 233W wall heating: 273W (does not sum up somehow. Possible power reduced to voltage drop on cables - high current OR PSU efficiency depends on load, which is quite normal). PSU only, 24V socket disconnected: 0.0W (may be less than 0.1W)