Summary

This a build started out to fix some problems with a damaged QU-BD RXL, then added some improvements, and then additional functionality. See the Instructions.txt for the functions this design addresses. Note the auto levelling needs more work - particularly with the upgrade of the firmware.
Add a y-axis spacer to ensure clearance.

Instructions

The QU-BD RXL machine I fitted this to had suffered significant damage due to very poor packaging during shipment. In the process of repairs (and to fix some of the know issues) the endstops have been moved or replaced, so be careful once you fit this shroud and fan mount assembly that you still have adequate clearances at the min and max of X and Y axis. You may have to bend the micro switch out on the Y axis to get a little more clearance as the extruder goes close to the Y Axis motor and the shroud may hit (or better still add the clip-on y-axis spacer).
This mode does a number of things.
The shroud part:-

Shrouds the hotend so airflow is concentrated on the cold side. This appears to help minimise heat leakage up the Hotend (better for PLA prints).
- Holds the Hotend firm. The default mounting is effectively a single bolt that the unit rotates around so print accuracy is lost. (Might not be too bad on a new Extruder setup ,? but as mentioned this unit got badly knocked about in transit so extruder was too loose).
- Feeds the filament directly to the centre of the extruder gripping wheels. The default setup has no guide and the filament does move around as it is pulled towards the feed source. Jamming appeared to be reduced significantly with the shroud fitted. I push in piece of 3m OD / 2mm ID tubing to help (I had some PTFE tubing I had got from aliexpress cheap) to experiment with Bowden feed drives. But as this is the cold end it does not need to be Teflon, it could be anything. Would probably be OK without the tube.
  The Fan Part locks onto the Linear bearings and then bolted to the shroud with two M3*25 bolts, so very solid. Be careful with axis clearances (added a clip-on y-axis spacer in build files). This;
- Adds to the solidity of the Extrude overall, and hold the shroud in place
- Has a fan mount (the default mount is no very good and broken in transit in this case)
- Protects the fan from damage (the one in this unit had a number of fins broken ( which meant the rest were easily damaged - did not work very well when only two fins left ?). I was able to source 24V 40mm fans easily and cheaply from aliexpress.
- Provides a mount for the auto levelling arm.
  The remainder are the parts to setup auto-levelling. This I have not attached and got this going yet as there is a lot more work needed.
- Wiring in the Switch and Servo to controller. (Azteeg X3 in this case). I have not yet looked at the I/O setup ,? but I expect the board to be capable.
- Updating the Repetier firmware to the latest release that has the auto-zeroing modules built in. This is a bit of a challenge as QU-BD have not and probably wont update the modified version of Repetier they use, so will need to translate the settings across (with a little help from the information provided by Illuminarti at www.extrudable.me).
  I printed this in ABS with the RXL Printer I was fixing. Sliced with Cura and printed with Repetier Host.
  The STL's and SketchUp Model files are attached .
  To fit well, remove the existing fan mount bracket (the one on this machine was broken off during shipping, so didn't have to - one advantage of QU-BD's packaging skills :) )

QU-BD RXL Extruder Shroud, Fan Mount, and Auto level