Description

Recently upgraded to the Micro Swiss NG for my Ender 3 v2. While the kit from Micro Swiss includes a shroud to use the stock 4010 axial hot end fan and 4010 blower part cooling fan, I wanted to use larger fans.

I looked around and found a few that were modified to handle a 5015 part cooling fan. They use the ducting of the stock shroud so one fan can cool from both sides. I printed and used this one for a while:

https://www.thingiverse.com/thing:5368323

But I wanted dual 5015 fans so I could run them at 50% speed, for the same amount of cooling at a much lower volume. I found some other shrouds that had dual 5015 part cooling fans, but they relocated the CR touch sensor to the front of the shroud, so I couldn't install a 4020 axial hot end fan. I actually modified one of them to move the CR touch mount further out, but that causes issues with bed leveling, since the probe can no longer reach the max y values.

So I made my own shroud that has dual 5015 blower part cooling fans, supports 4010 or 4020 axis hot end fans, and keeps the stock location of the CR Touch sensor mount. I used this model as the base of my modifications:

https://www.printables.com/model/197251-simplified-micro-swiss-ng-extruder-shroud

Its basically the stock shroud, with all the rounded edges removed. I eliminated the cross over, so each 5015 fan goes only to 1 outlet. The flow paths aren't exactly the same, so I wanted to make sure I wasn't unevenly cooling one side of the print.

With a 4020 hot end fan, you are able to screw in 3 mounting screws. There is overlap with the 4th screw and one of the 5015 mounting screws, so just don't install the 4th screw. 3 is plenty to hold it in place.

1. 4020 Axial fan - 3 M3x25mm screws (I also use M3 washers). These screw right into the shroud, be careful not to over tighten them.
2. 5015 Blower fans - 2 M3x20mm screws and 2 M3 nuts (I also use M3 washers) per fan. There are circular indents to hold the nuts, but getting the nut that is near the 4th 4020 mount into place is tricky. I used curved needle nose pliers to push it into place and hold it there while screwing in the mount

When printing, you need to block all supports except for the 1 primary underneath surface, otherwise, the slicer will try and support the internal surfaces of the fan ducts, which won't be removable. Look the image with the purple surface highlighted.

I am using this for the CR Touch mount:

https://www.thingiverse.com/thing:5364814

The bracket is mounted to the Micro Swiss NG frame with the stock screws. For mounting the CR Touch to the bracket, I am using 2 M3x10mm screws and M3 nuts. Its a tight fit, but it works. Mount the bracket first. Then plug in the CR Touch, then mount it to the bracket. Screws come in thru the bottom, with the nuts on top, between the bracket and the stepper motor.

Since the stock shroud doesn't have a place to mount wires to, i printed this part. Its extremely useful and keeps you from putting strain on the thermister and heater cartridge wires.

https://www.thingiverse.com/thing:5467541

Since I am running a reverse bowden setup, I have the filament going through a bowden tube from the Micro Swiss NG all the way back to a filament dryer. Trying to change out filament by pushing and pulling at the filament dryer is impossible, so I added a magnetic disconnect right above the NG. When I want to change the filament, i just pull this joint apart and I can grab the filament to push and pull it out. I am using capricorn tubing (4mm OD, 1.8mm ID) for the short tube from the fitting to the NG. For the run from the fitting to the filament dryer, I am using 4mm OD, 3mm OD PTFE tubing. You want it loose to reduce friction as the NG pulls and pushes filament.

Magnetic Fitting:

https://www.printables.com/model/32368-join-ptfe-tubes-together-magnetically

Large ID PTFE Tubing (4mm OD x 3mm ID)

https://www.amazon.com/gp/product/B07B8CK8L9/

One other modification I made was to have the hot end wire bundle come out the side of my printer. This lets me keep the wire bundle and bowden tube in front of the printer, so the x gantry can reach the full 250 mm height without any wires hitting the top cross bar. To help hold the wire bundle and tubing in place, I created a replacement for the x limit switch cover. It has a print in place swivel that easily rocks back and forth and holds the bundle in place as the print head moves side to side.

https://www.printables.com/model/375913-combined-cablebowden-tube-swivel-and-x-axis-limit-

For the filament dryer, I modified an existing Sunlu S2 wedge to accept an angled bowden fitting:

https://www.printables.com/model/372661-sunlu-s2-wedge-with-angled-bowden-pnuematic-fittin

To print the shroud, see the attached photo. I put the surface that goes against the Micro Swiss NG as the bottom, then used standard supports with a grid interface. I used a 0.2mm layer height, and did a 0.2mm offset between the support grid interface and the model. You need to use some pliers to get it off, but it will come off clean and leave a nice surface, which you don't even see. I used support blockers on all the holes and anything that wasn't the primary surface that needs supporting.