Kossel SKR v1.3 mount with quiet ducted cooling

cults3d

This is a mount for an SKR v1.3 into a Kossel printer. I'm using it in my Anycubic Kossel Linear Plus for an easy upgrade to TMC2130 drivers (making it super quiet) along with a Raspberry Pi (see thing 4015230) to run Klipper firmware. The cables can be routed as shown, or you can route the stepper cables under the board and up through the slots next to the stepper drivers if you use feet (if your printer is slightly raised). The part named "power-port" provides a mount for the fan, the duct, and an XT60E-M connector. I wanted this so I could easily disconnect my power supply and prevent anything that might snag the power cord from putting strain on the SKR v1.3 board's connectors. I used Amazon item B07YJMCDC3 (in case you want a bundle of them or are in too much of a rush to buy from Mouser or Digikey). The duct mounts to the above part, sandwiching a 4020 blower fan. Having the intake of the fan within the ductwork reduces noise significantly, since the intake is the major source of noise in that type of blower. The air is drawn partly through the obvious holes in the face of the duct and partly through the gap between the drivers and the duct opening. Having the heatsink fins aimed so air coming through the duct holes goes straight into them is likely beneficial here. The warmed air is ducted out of the printer through the "power-port" part. The main mounting holes are sized for M5 screws, but smaller will work with washers. The XT60E-M (if you bought from Amazon using the item mentioned) comes with its own M2.5 screws, the holes are sized for those. The SKR v1.3 board mounts with M3 screws, directly into the printed plastic. The holes are 2.8mm diameter, so the M3 screws will cut threads into the plastic if you turn slowly with pressure at first. This works best with PETG, but also works with PLA. I'm using a 24V fan on the 12V power and it draws enough air through that I've not had any signs of the drivers heating up. The loudest part (aside from the power supply fan) is the endstop switches. Update: I raised the amperage of my steppers to 1.1A and started having problems that I suspect may be due to overheating of the TMC2130s. I lowered the current back down and the problems stopped. I'm going to switch to a 12V fan, but drive it through an MP1584EN buck-converter to lower the voltage to keep the fan quiet, but run it a bit faster than the current one. Update: It turns out that cooling wasn't the problem. I was overdriving the TMC2130s beyond Trinamic's specs (0.96A RMS) based on the vendor's spec (1.2A RMS). Keeping the amperage under 0.96 solved the problem, even with the underdriven 24V fan. Be sure to have all driver sockets populated to prevent too much air from bypassing the heatsinks!