This is an improved revision of my previous "Adjustable E3D V6 impr. fan adapter and modded Prusa MK3 Layer Cooling" (https://www.thingiverse.com/thing:3512817), which was a redesign and remix of thed0ct0r's "E3D V6 improved fan adapter with modded Prusa MK3 Layer Cooling", https://www.thingiverse.com/thing:2769783 .
[the part "clip with sliding guide and screw slot" has been revised June 18, 2019, to fix a reported interference problem. A "STEP" file has also been generated and added to the file list (though its usefulness may be in question, I don't have software to work with STEP files)]]
This version is changed for slightly stronger and more stable structure, but mostly to provide capability for the 5015 part cooling fan to sit to the left rather than to the right of the nozzle (though still in front of the nozzle, for minimal overall width of the hot end and cooling arrangements). Having the fan on the left is good if the right-side positioning would interfere with other things such as a bed level sensor such as BLTouch. But it also lets the fan draw air from above, rather than from right off the bed with the fan's 45 degree angle (ala PRUSA MK3). This should provide better cooling, and also avoid problems that some MK3 users have had with fan motors making noise or burning out by having the fan blades angled downwards.
It still uses thed0ct0r's heatsink cooling fan mount design, which he has shown to provide better performance than usual way that is done. And, even better, it also provides a very nifty mounting for the part cooling fan arrangement, which lets you just unclip or clip back on the part cooler stuff, making for extremely easy access when changing nozzles or servicing the heat block area. This heatsink venturi cooling fan design is a direct file copy of thed0ctr0r's design from his posted design.
The part cooling fans here provide quite a bit of versatility. First, like my previous version of this, the fan sits at an angle of 45degrees, like the current PRUSA MK3 fan design, providing a more direct heat path. My reasons for doing it, though, were mostly because leaning the fan allows me clearance to make the part cooling fan's height adjustable. The same parts can be used with normal V6 heat block or with Volcano heat blocks, and lets you fine tune the height where you want it with just a single M3 screw.
The part cooling duct is now provided in three different options (actually, six, since it is given for both left side default arrangement or for right side). The original design had the air flow from the duct directed primarily downwards onto the bed for generally cooling general area of the part. I found, though, that I needed the air to go more horizontally to directly below the nozzle as the extruded filament wasn't always cooled quickly enough (I use a volcano set). So I made a version (version 2) duct with openings that are more side-firing. And another version (version 3) that is still MORE side-firing. I use the version 3 myself, but if you want something more like thed0ct0r's duct design, use the version 1.
So, when you dowload and slice, select first whether you want left-side mount (the default files) or right side mount (with "To Right" in the STL file names). Then select the duct style you want (1 fires most vertical, 3 fires most horizontal). The same "30mm_clip_with_venturi_v3_50_by thed0ct0r" file works with any of these versions.
To clip the fan and duct arrangment to the heatsink mount part, tip the duct forward and put the tooth of the clip into the slot at the bottom of the heatsink mount part. Then push the upper part of the clip toward the heatsink till it snaps in place. To remove, insert a small screwdriver or blade slightly between the clip and mount while pulling on the clip until it unsnaps. It will get easier to remove after several clip/unclip operations.
(In keeping with the GNU - GPL license, the Fusion360 file for this is published at https://a360.co/2Rc5zvw . But the file is large and includes many versions of many designs, so don't take it as any example of good design flow!)
The "5015 sloped layer cooling..." and "30mm clip with venturi..." part(s) have insets to hold 3mm nylock nuts. These are best installed on these parts before assembly, draw them in using a 3mm screw, then remove the screw and combine parts with 3mm screws.
You will likely need to insert a flatblade screwdriver between parts to unsnap them the first few times until the snap-together parts wear in a little. If too tight for convenient removal still, file down the teeth on the "Clip with sliding guide" parts a little.