SKR Mini Rearcase for Ender 3

thingiverse

I wanted to utilize teaching techs rear case but it wouldn't fit my SKR mini. So, I created these files to work in conjunction with the existing designs. You will still need the raspi case and lid from the original source, as well as the new SKR case and new lid. A notable point before proceeding - to accomplish this modification, you need to have the skills to extend or be willing to purchase an extended Z-stop cable. I didn't like the airflow in the original so I used two push pull fans on either side of the case. Air enters on the raspi side and exits on the SKR side. These will both eventually be noctua 5V 40x20mm silent fans controlled by the raspi but I am still waiting for one to arrive. With the fan in its new position, the previous cable management didn't work so I made a modification to the SKR lid with the cable hole halfway down. This makes removing the covers slightly more challenging as you have to slide the whole unit out at the same time (see last image), but I felt that this was a reasonable inconvenience versus improved airflow. If I were to design this again, I would potentially place the fan in the other corner towards the back of the printer. The original design isn't perfect in that it sags in the middle. If I were to redesign this from scratch, I would link to the centre rail somehow. It's not really an issue with the previous model but with the new push/pull airflow, I can't have the gaps at the front where it has sagged down. I intend to print a small support to push up under the front of the box in the middle. This design still has slots for the raspi buck converter, but as I use a mains relay, I don't utilize those slots. My mains relay design can be found here: https://www.thingiverse.com/thing:4491723 Update 23/06/2020 - I decided I wanted a bit more room for the left-hand cables on the SKR lid so I trimmed a bit off on my built model. I have updated the model here with an extra 5mm of clearance. I've been running cooling tests throughout the day, and the fans are working perfectly in the push pull configuration, giving a constant internal temperature of 10 degrees below no load in open air. Big success. I've got a spare noctua 40x10 12V that I'm going to use with the buck converter mounting slots to replace the hot end fan. I have also printed a tray support to sit under the join between the left and right sides. I won't upload this file as my Ender sits on spring-mounted feet, so the height will vary from yours. It's just a square extruded into a rectangle, with the front-to-rear length of the trays. The sides of the squares equal the height from the bottom of the tray to the desk. Update 1 Jul 20 - In response to a request, I have uploaded a right-mounted board design for easier access to the SKR. This has meant removing the second fan. Until I say otherwise, this design has not been printed so use at your own risk!