INDX Stealth Changer Tophat Bowden+FIlamnent Sensor

WARNING: I have removed the filament sensors from my printed version of this as I was experiencing inconsistent extrusion and felt that the friction the switches added may have been too much for the INDX extruder.  I am working on a hall-effect sensor version of this but have not finished it yet.  Use the back-panel with filament switches with caution.  I have uploaded a version of the backplate that is only a resized version of the original model I remixed.  That means there is no ECAS and no filament switches in the geometry.  I will work on adding ECAS only to the backplate.

This is a remix of Yahms Tophat back panel for toolchangers for a 300mm Voron.  Unfortunately, the original does not fit the sizing needed for a stock Stealth Changer top-hat (it is too big).  As such, I sized it down to fit.  While I was modifying it, i also took the filament switch geometry from the Enraged Rabbit Carrot Feeder (ERCFv2) to add a simple filament switch on each lane.  Finally, I added a back-plate add-on bar to hold, retain, and allow tweaking of 3mm spring wire to bowden tubes (along with accompanying bowden wire retainer segments).

I recommend printing these panels and installing them WHILE you build the top-hat frame. It is a pain in the ass to align all the T-Nuts and insert the panels (they are true to size without much give) when the frame is already built.

BOM (Required):

8          PC4-M10 pneumatic quick-connect couplers (example link: https://a.co/d/05MWVFJy )

8          ECAS04 pneumatic Connectors

14        T-Nuts for extrusion mounting of panels (roll in or regular.  I recommend spring roll-ins)

14        M3x8mm or M3x10mm SHCS  (Have both on hand, both should work but sometimes engagement of T-nuts is more difficult with the 8mm)

8         Micro-switches.  They dont need to be Omron.  Almost any will work.  (I used cheap ones like these:  https://a.co/d/04XN8PZW )

8        5.5mm Ball Bearings  (Be very careful, some shop listings claim the ball-bearing is 5.5, but they are not.  An example can be seen in the pictures attached.  The ball bearing MUST be 5.5mm.  You can even get away with a bit smaller, like 5.4 or even 5.3.  But NOT larger.)

16      M2x10mm Self Tapping Screws (2 for securing each filament switch to its place. Example link: https://a.co/d/08Xv3RsD )

Optional 3mm Bowden Wire Guide BOM:

?         .3mm X 3mm Flat Spring Wire (This is the spec for the Stealth Changer, so I just went with it. The amount needed will vary based on your set-up.  I required about 800mm of wire per tool)

5         M3x10mm BHCS or SHCS (I think BHCS looks cleaner but it doesn't really matter)

16        M3x4x5 heat-set inserts (Voron spec)

8         M3x8 BHCS or SHCS (For securing 3mm wire when inserted in each chanel.  Unscrew the screw to adjust the wire as required.)

Important printing notes:

• I designed these parts true to size, without much wiggle room.  I printed mine in ABS.  There is NO shrink-factor baked into the parts like with Voron parts.  It is assumed you have calibrated your printer and filament to print true-to-size.

• Print the wire-holder segments in TPU if you can.  I printed mine out of 85A TPU with 40% infill. But really, any TPU should work.

• For a full back-panel, you will need to print 2 of the Side Panel parts below.

Important build notes:

• The models are a little…rough.  But they work and I didn't feel like making them prettier or parametric. 

• You do not need to remove any parts of the ECAS fitting before inserting into the back of the plate.  The ECAS fittings should fit well. If they are too loose, just add a tiny dab of super-glue.  Be careful not to glue moving parts of the ECAS.

• The fit of the panels is exact.  This is a good thing imo, but requires some force to get them inserted if you are inserting them in an already built tophat frame.

• You will need to find an MCU to connect the switches to.  I plan on using an old ERCF V2 board since it has the IO.

• The filament switches need their legs bent upwards and soldered wires similarly need to be soldered pointing up as there is very little clearance between the lanes.  Insert a ball bearing and then place the filament switch so that its button is inside the hole (See attached pictures for guidance).  For further guidance in attaching the filament switch, see the ERCF-Cotton Tail documentation as it is the exact same filament switch set-up/geometry. 

• The filament switches can add some drag to the filament.  This is both a good and bad thing.  The good thing is you are unlikely to have filament leave the tools when bumped.  With my INDX dev-kit, I did not notice any difficulty with feeding to tools.  Even when I fed the tools from PolyDryer boxes sitting on the table next to my Voron.  Still, it is likely best to minimize filament drag at all other points between the switches and wherever you are feeding filament from.  

• You will notice natural slight variation in drag on filament inserted through the switches.  They are very simple filament switch set-ups and are sensitive to the minor variations inherent in printing (i.e. too narrow hole for bearing, etc…) as well as the slight variation introduced when the self-tapping screws are put in.

• Print the bowden wire holder segments in TPU.  I sized them to fit almost exactly.

• There is no retaining mechanism within the TPU bowden segment end part.  Friction and the spring pressure of the wire keeps it in.  If the wire is coming out of it, you should adjust the length/spring pressure of the wire to make sure there is slight downward pressure to keep it inside the end.  

• There is no STEP file as I did all this work in tinkercad as I lack legitimate cad skills :D