RAMPS & MOSFET Case by 8SquareFeet

Last crawled date: 3 years, 1 month ago

While building my new CoreXY printer, I wanted to consolidate all of the electronics into one case. So, this is my take on that.
I designed the case so that all of the power and communication lines enter the rear of the case, and the ribbon cables running to the display exit the front.
Air flow is from rear to front, passing over the MOSFET first, then baffled down over the "open" end RAMPS boards, finally exiting the case at the front under the ribbon cables.
The fan is mounted externally. I'm using a single 40mm, high CFM fan I salvaged from a server, so my cooling has been fine. However, if cooling does seem to be an issue, you could easily mount additional fans on the case and drill holes for airflow.
In testing, using a lower CFM fan, I found that while printing (no heatbed), I would see a one or two degree rise above ambient room temperatures (21C in the room, 23C at the exit of the case). If using the MOSFET, I saw a much higher delta. With the heatbed running at 95C, I was seeing 21C in the room, and 40C to 42C in the exit airflow (about 107F). All of the electronics are rated up to about 85C max (so sayeth the Chinese Mfgr's), but that's still quite warm. Hence, the higher CFM fan.
The base and side are one piece each, and they are pretty big (196mm long), so you'll either need a decent size printer, or you will have to edit the STL and make them two-piece parts. I'm busy at the moment, but I'll try and break them apart as soon as I can.
The ends and the tops are small enough that most printers should be able to handle them.
I built in access to the USB and power ports, and some basic cable management by raising the MOSFET board. Power and USB run under the MOSFET, everything else runs around the stand-offs. This keeps wiring out of the airflow for the most part.
I've included the mounts I'm using to attach the case to my printer. These are designed for 15mm X 15mm MakerBeam XL extrusion. The case could be used without them for any printer. If you use the mounts, leave the mount-side corner screws out on the tops.
The mounts have slots in them to allow velcro to pass thru them, securing the case to the mounts. You could use wire or zip ties. Depending on how they are printed, they will probably need some supports.
I'm using locally sourced hardware for assembly (6mm x 3.4mm countersunk screws). The holes were drilled out using a 3mm drill. It could be assembled using 3mm hardware as well.
Everything was printed in PLA, flat side down, no supports, 3 perimeters and 2 top and bottom layers. Infill was 20% I think.
The Mega was mounted using 2mm hardware. The MOSFET uses 3mm X 6mm hardware.
I found attaching all the cabling to the RAMPS prior to installing the MOSFET worked best.
This is the MOSFET I'm using, but the mounting is about the same for all of the units like this one:https://www.amazon.com/gp/product/B01MY50JL3/ref=oh_aui_detailpage_o07_s01?ie=UTF8&psc=1
WARNING!!
I've had two of these type of MOSFET's (different Mfgr's) fail on me now. Both of them failed in the ON mode. The cheapest is often just that..... BE CAREFUL with these things!