SKR Pro v1.2 Case with many GX16 connector holes / vent holes

thingiverse

Update 7/28/2021: I printed the box at 0.28mm layer height. In Fusion 360, the width of the box can be measured at 118.11mm. On my particular print, I measured the width of the box using quality 6" Mitutoyo digital caliper at 117.8mm (my actual printed box is small by 0.31mm across the case width based on my particular printer calibration). I have 8" calipers also so I'll check the length difference between the model and my print also. The circuit card mounting holes are very closely aligned but there is less than 1mm misalignment with an actual SKR Pro v1.2 circuit card (enough to partially offset the mounting hole). I thought there might be an error in the design but I studied measurements for the board step file in Fusion 360, measurements of this base model in Fusion 360, and took real measurements with my caliper from an actual SKR Pro 1.2 board looking for any errors with the mount positions. I found no errors. Everything is accurately modelled and appear to match measurements taken from an actual circuit card which match the SRK Pro 1.2 step file found on BTT's github so I attribute the mounting hole alignment discrepancy to my 3D printer calibration. I plan to drill out the four mounting holes to enlarge them to both adjust the hole alignment and to install these threaded inserts which should resolve the minor alignment issue: https://www.amazon.com/Uxcell-a16041800ux0824-Knurled-Threaded-Embedment/dp/B01IYWTCWW/ref=sr_1_10?dchild=1&keywords=m3+threaded+inserts&qid=1627580035&sr=8-10 Be aware that I did move the relative mounting hole position for one of four circuit board mounting points that this is a remix from by 0.5mm per the board step file provided by Big Tree Tech's github. I determined that this was a valid change. I measured a SKR Pro v1.2 circuit card carefully and believe the board step file on BTT's github is correct and matches the actual circuit card mounting hole dimensions. I'm not sure if the SKR Pro v1.2 mounting hole positions changed over time but I see a few cases on Thingiverse out there with suspect mounting hole locations. It is a nice box design I think. The GX16 connectors fit in the holes snugly so they shouldn't rotate easily as the connector threads grab onto the hole walls (for my printer anyway). The power connector also fits well in the smaller 11.2mm hole. Note that I changed the upper and lower hole positions on the long side with the most holes so that the smaller power connector hole is on the top corner instead of the bottom corner. This was necessary because the power connector part that I provide the link to below was long enough to interfere with the fuse on the circuit card. Moving it higher allows it to clear the board. I still need to assemble everything. ----- This is a remix of the nicely designed "SKR PRO case remix" by vandenmar: https://www.thingiverse.com/thing:4870495 Which was based on the "SKR PRo V1.2 + TFT35 E3 screen mounting box for MPCNC" by Bobbond000: https://www.thingiverse.com/thing:4622952 Thanks to all the folks who shared their efforts. The .step file was a great help! I remixed the design to add nineteen holes to support GX16 aviation connectors and one smaller hole to support a power supply jack. This may sound like overkill but the unused connectors are intended to serve as ventilation holes and allow flexibility with respect to wiring needs. There are GX16 connector holes positioned so that wiring can go vertically down into the circuit card driver connectors to minimize the wiring in the box to the drivers. I envision fans blowing in form the front and exhausting though all the unused GX16 connector holes. This design uses these GX16 connectors: https://www.amazon.com/gp/product/B07D7SHKGK/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1 The power supply jack I am using is this connector: https://www.amazon.com/gp/product/B08CRBGCY3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 which has wires labelled 18 AWG wire (I used calipers to measure approximately a 0.96 to 1.0mm conductor diameter on the tinned ends which I think is OK): I found that the power jack physically fits a Kaster 12V 6A "Replacement AC adapter" part number N18061 with a cord labelled to use 20 AWG wire: https://www.amazon.com/Kastar-Adapter-5-52-5mm-Wireless-Security/dp/B003TUMDWG (center is positive) I bought these 40x40x10mm 12V fans: https://www.amazon.com/gp/product/B0757LXKST/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1 This base should be compatible dimensionally with the cover plate and LCD holder from vandenmar's design that this is a remix of. I included the same cover plate here except I added though-holes for (4) M5 screws. I may remix this design further in the future and anticipate breaking backward compatibility with vandenmar's design so I am posting this version that should be compatible now for anyone interested. In a nutshell I: 1. added nineteen GX16 connector holes (I used 15.75mm diameter holes; actual connector thread measured with calipers is 15.37mm so I anticipate these should fit without much effort after printing. I had printed a test print with hole size of 15.5mm and needed channel lock pliers to get the threads to cut so I increased the hole diameter by another 0.25mm). 2. thickened the four walls by 0.8mm (thickness added to the internal wall dimension so the ledge is wider for the top plate) to better support the GX16 male and female connectors and cables. 3. created larger mounting pads for the circuit board and raised the height of mounts slightly. One pad is notched to clear a solder connection for a fuse component on the SKR board. I also moved the mounts inboard further so USB connector does not protrude from the case. 4. adjusted the relative orientation of one mounting hole by 0.5mm based on SKR Pro 1.2 step file from bigtreetech's github as well as measurement I took from an actual SKR Pro v1.2 board. 5. added slot in case to support an ESP-01S WiFi module. 6. increased height of the case by 1mm to ensure clearance for the upper GX16 connector hex nut (worst case hex nut orientation). 7. separated the two 40x40x10 fans by an additional 6mm and integrated the thicker fan mounting area into the entire end wall. I also made fan mounting holes go all the way though the end wall. 8. reworked the USB connectors and micro-usb slot positions and dimensions based on thicker walls and slight change in board mounting pad height. Locations determined based on the SRK Pro 1.2 step file model. 9. increased the thickness of the corner posts and made the screw holes completely through (the tops of these holes mount the lid. I am thinking about using the bottoms of these holes to mount the case onto a surface. These holes are 4.5mm diameter to accept M5 screws. 10. Added through holes in top plate for M5 screws. (also sharing the stl file of the top plate with through-holes) 11. Added 11.2mm diameter power jack connector hole. If you are interested in modelling the GX16 connectors, there is a model here: https://grabcad.com/library/gx16_4pin-aviation-connector-1 If you would like to model the SKR Pro 1.2 circuit card the step file was found here: https://github.com/bigtreetech/BIGTREETECH-SKR-PRO-V1.1/tree/master/SKR-PRO-V1.2/manual I included the step file for the base that was created from the step file from vandenmar's design and should be compatible with his other components. Enjoy!