Bare Bones Ender 3 / V2 Fan Shroud

Introduction: After trying numerous fan shrouds/ducts on my Ender 3 V2 and not being completely satisfied I thought it was time to have a crack at my own.  Although still not completely satisfied I've been using for quite a long time now with absolutely no issues, this is probably one of the ugliest fan ducts getting around but it just works.  There were a few key design criteria going into this:

• Direct more air over the heat sink and less onto the hot block and print and eliminate heat creep.
• Provide better visibility of the nozzle while printing.
• Able to be printed as a single piece with minimal support.
• Suitable with stock fans or upgraded 4020 heat sink fan. 
• Provide a dual part cooling fan option sill compatible with BLTouch in standard location.
• Easy to install and easily removable for hot end maintenance.

Several versions have been published over time that have incorporated feedback from users, these have all now been consolidated into a bolted and clip-on option, both in either single of dual part cooling fan configuration. 

Installation steps are as follows:

1. Completely dismantle the stock fan shroud / housing, removing both fans. Retain the screws for the heat sink fan.
2. Install the shroud onto the heat sink:
   • Clip-on - It should just pop over the heat sink somewhat satisfyingly. There are recess' for the heat sink mounting bolts and heat break grub screw that should help locate it onto the heat sink.
   • Bolted - Remove the two M3x16 bolts securing the heat sink to the x-gantry (bolts highlighted red in photo with bolted option), visually align the holes on the fan housing and heat sink and pop the housing onto the heat sink as described in the previous step.  Fasten the heat sink and fan housing to the x-gantry using the original screws, the bolts should still be plenty long enough but if required the small spring washers can be removed. 
3. Install heat sink fan onto the new fan housing/shroud with the stock screws if using stock 4010 fan or longer screws as required for a 4020. 
4. Install part cooling fan, no screws are required just ensure it is properly seated.  This is a tight fit but it will go on, sometimes it helps to get it started on one end and then work it towards the other.
5. Get back to printing and if you've got the time leave me some feedback with any issues or suggested improvements so that I can continue to iterate and improve.

Print Settings: Suggest printing with PETG, ABS, ASA or other materials with at least equivalent heat resistance.  Layer height of 0.16-0.20mm and line width of 0.4-0.6mm.  Personally I think this part is small enough that it can just be printed solid, supports will be required at least under the part cooling fan duct for a decent finish and where the bolts sit on the bolted versions.

A few disclaimers at this stage which I will update if there are enough makes with experience to alleviate the below:

• I have only used with a 4020 heat sink fan, however, given that this will deliver significantly more airflow over the heat sink than stock I can't see it being a problem with a 4010. 
• As a result of the above, you might find you need more part cooling than previously as some of the air from the heat sink fan in the stock shroud was assisting with cooling the part.  For e.g. with a stock shroud or the other community developed ones I had tried previously I didn't use any part cooling for PETG, whereas now I find about 15% with a single fan is about right. 
• If using the clip-on version, due to the bare bones nature of this and the way it's mounted I can't say it would be recommended for a machine with accelerations significantly above stock.  The fit has been increased over time to as tight as possible, if you're using the bolted version then there shouldn't be any restrictions.  
• I haven't used the dual part cooling fan variation, however, I also can't imagine this would cause any issues. 

Look forward to hopefully seeing a few makes!

P.s. for what it's worth and based on user feedback, if you're not planning on regularly removing this fan housing then the bolted version is recommended to ensure a continued tight fit.