Abbn for 4020 (#498)

* Initial commit of ABBN for 4020

* corrected format error

* Update Readme.md

adding an extra line after the headings so they hopefully appear as headings.

* updating readme for 5015 and 4020 abbn

these are also compatible with trident and VSW

* fixing issues with stl name, readme, and adding in Rapido support

In addition to fixing the naming issues, and readme issues, I am adding in support for Phaetus Rapido.

* Update README.md

adding Rapido to description in readme

* fixing rapido stls

printer_mods/Badnoob/ABBN_for_Stock/Readme.md

@@ -0,0 +1,46 @@
+# AB-BN for Stock
+
+This is a revised Stock toolhead for the Dragon or Rapido hotend. It takes the technology from AB-BN and ports it for use with the stock Afterburner Assembly.
+
+This allows you to use the stock Afterburner 4020 based part cooler and reduces the potential for jamming.
+
+The only real use case I know of for this is for someone who does not have a 5015 fan.
+
+# Why? 
+
+The stock Afterburner was designed for a full size E3D V6 hotend.  The Dragon uses a much smaller heatsink.  The result of this is that the bulk of the airflow bypasses the heatsink on the Dragon.
+
+In addition, the stock toolhead blows a lot of air onto the bed.
+
+Finally, the stock ducts tend to melt and warp over time.
+
+I also added support for Phaetus' Rapido toolhead.
+
+
+# How does this fix anything?
+
+AB-BN was developed over the course of 2020 and 2021 to solve several issues with the stock afterburner airflow.  Dozens of prototypes were modeled, simulated, printed, and tested.  In the end I found that cooling was improved if we:
+1. Use a cone to help streamline air exiting the fan.
+2. Use a stator to increase static pressure.
+3. Reduce the duct to force air past the heatsink
+
+This reduces the overall airflow and increases the airflow that matters to the toolhead.
+
+I also included the bleed air channels that help reduce part duct melting.
+
+# Should I use this or the FULL AB-BN?
+
+This solution is aimed at someone who wants to keep using most of the stock Afterburner, but needs a little less hotend jamming.
+
+I recommend you use the full AB-BN if you can.
+
+# What toolheads are supported?
+
+I have support for Phaetus' Dragon and Rapido toolheads.
+
+For Dragon, you do not need a new back piece, the stock dragon back is fine.
+
+For Rapido you will need both front and back pieces.
+
+
+

printer_mods/README.md

@@ -50,7 +50,8 @@ like so:
 | |[MGN12 X-axis](./arkeet/mgn12/)|Replaces the dual MGN9H rails with a single MGN12H. |:x:|:x:|:heavy_check_mark:|:x:|
 | |[V0 DC inlet](./arkeet/v0-dc-inlet/)|Skirt inlet for external 24V DC power supply. |:heavy_check_mark:|:x:|:x:|:x:|
 |Badnoob |[Precision AB Drive](./Badnoob/Precision_AB_Drive)|Changes the gearing for the AB drives to improve both resolution and torque, with a strenthened frame. |:grey_question:|:grey_question:|:heavy_check_mark:|:x:|
-| |[AB-BN Afterburner mod](./Badnoob/AB-BN)|Improved Afterburner with 5015 fan |:x:|:heavy_check_mark:|:heavy_check_mark:|:grey_question:|
+| |[AB-BN Afterburner mod (5015)](./Badnoob/AB-BN)|Improved Afterburner with 5015 fan |:x:|:heavy_check_mark:|:heavy_check_mark:|:heavy_check_mark:|:heavy_check_mark:|
+| |[AB-BN for Stock Afterburner (4020)](./Badnoob/ABBN_for_Stock)|Improved Dragon and Rapido toolhead for stock Afterburner with 4020 fan |:x:|:heavy_check_mark:|:heavy_check_mark:|:heavy_check_mark:|:heavy_check_mark:|
 | |[Rail Alignment](./Badnoob/Rail_Alignment)|Tools and procedure to properly align the rails in 2.4 and Afterburner|:x:|:x:|:heavy_check_mark:|:x:|
 |Baltojikale | [LoudOwl aka Stabby](./Baltojikale/LoudOwl_aka_Stabby) | Alternative dual 5015 part cooling fan toolhead for Afterburner | :x: | :heavy_check_mark: | :heavy_check_mark: | :heavy_check_mark: |
 |beaugalbraith| [Nova Printhead](./beaugalbraith/Nova_Printhead) | Use Nova Hotend with Afterburner | :grey_question: | :grey_question: | :heavy_check_mark: | :grey_question: | :grey_question:|