AC Bed SSR Box

thingiverse

I designed and built this AC Bed SSR box. I have three printers modified to use AC power using this box for a much faster warm-up time on my 300mm-sized beds. Many 3D printers rely on low-cost Power Supply Units with limited lifetimes at the top of their power ratings. Switching to AC power for your heating bed greatly reduces the demands on your PSU and will likely increase its life expectancy significantly. You will need the following items to complete your own: - Solid-State Relay (SSR) - Silicon AC heat pad - AC inlet with rocker switch - 40x40mm fan - 4x M4 screws for the lid - 2x M4 to secure the SSR to the heatsink - 2x M4 or M5 to secure the heatsink to the bottom of the box - 4x M3 screws for the cooling fan - Wire of sufficient gauge - Soldering iron and screwdrivers The SSR sends AC current directly from your wall outlet to the heated pad. It is controlled on and off by a small DC current, coming from your existing heated bed port on your 3D printer. The common 40x40mm fan draws heat out of the box and is fed by the heated bed port from your 3D printer controller board, at the same time that same signal drives the SSR. The DC side of the SSR and the cooling fan are connected in parallel. Whenever the chip on your controller board activates the Heated Bed port, the SSR turns on as well as the fan. I use old and beat-up fans, and the noise they make lets me know whenever the heated bed is on. There are several sources for these parts. Here are some I used: SSR: - SSR-25DA, SSR-40DA, and Heat Sink https://www.ebay.ca/itm/25A-40A-100A-SSR-25DA-SSR-40DA-SSR-100DA-250V-Solid-State-Relay-Module-Heat-Sink/122855145065?ssPageName=STRK%3AMEBIDX%3AIT&var=423306029021&_trksid=p2057872.m2749.l2649 Silicone bed: - Lower-cost 300mm Round AC Bed (20$us) https://www.robotdigg.com/product/562/300mm-Round-Silicone-Rubber-Heater-Pad Lower-cost 300x300mm AC Bed (20.50$us) https://www.robotdigg.com/product/115/300-or-310mm-CR-10-Silicone-Rubber-Heater-Pad Keenovo has a large selection of high-quality heating pads - https://www.keenovo.com/info/shop.html More expensive at 69$ for a Keenovo 300 x 300mm - https://www.amazon.com/gp/product/B00V81ZI70/ref=as_li_tl?ie=UTF8&tag=3dkc-20&camp=1789&creative=9325&linkCode=as2&creativeASIN=B00V81ZI70&linkId=89d8faa054e270e3c94849262c00dce4 AC Inlet with rocker switch: This diamond-shaped inlet is fused and available widely. http://amzn.to/2hejnXb 40x40mm 12v fan: https://www.amazon.ca/Extra-Quiet-Brushless-Cooling-AV-F4010MB/dp/B01KX0U8HG/ref=sr_1_7?crid=1O15PBNKHHIV4&keywords=40mm+fan&qid=1577297763&sprefix=40mm%2Caps%2C163&sr=8-7 There is a similar version without the ears and using springy grips to hold the AC inlet in place. I prefer the ears and screws for a more positive attachment. A 350 watts AC heating bed only draws 3 amps at Jterranella has a similar design but it is not using the heat sink for the SSR. Check here for his Thingy: https://www.thingiverse.com/thing:1844330 For more information on how to convert your 3D printer to an AC Heated Bed using a silicone hot pad and SSR, check this tutorial - 120VAC Silicon Bed controlled by SSR - 3D Printing https://www.youtube.com/watch?v=rjmCIzG2v5g