Prusa XL Tool Changer Extrude Nozzle Cleaning Brush

prusaprinters

UPDATE 03/03/24 - V8Fixed 3030 Notch Size.WHY DOES THIS EXIST?So one of the things I've noticed about the 5TH is that for layers where an extruder doesn't have a lot of use of a given material on a layer (like vertical text for example) go so fast that over the course of several layers those nozzles tend to “gunk” up a bit.There's several solutions to this but the Extruder dock based vs the front bed based have a lot of advantages, as there's no GCode mods required, you get a couple passes over the brush cleaner with every change of the tool, and they're out of the way.Every time you change tools you get a satisfying little scrubby sound as the nozzle passes through the brush.So while there's others out there, read on to find out why I made my own.The Sister Part:I've also created a front bed mounted version that gets used at print startup which you can find here:https://www.printables.com/model/748775-xl-front-mount-nozzle-brush-using-voron-fysetc-bruWHY A BLOCK BRUSH?I looked at the other one folks have made and most involve a “pencil” style vertical brush, which can be tough to consistently source.   Mostly though, I worry about the longevity of these brushes, as looking at my Dremel kit usage, the “vertical” fan type brushes wear out after just a couple uses with a Dremel, most likely due to the brass strands being relatively isolated.    So I wanted to go with a more traditional block type brush and found the there's a nozzle brush for the Vorons that is used in a bunch of different designs that have had thousands of makes.   Being as FYSETC and several other 3d Printer parts places sell these things, and they're readily available, and dirt cheap as well.  This will allow me to use the exact same brush for both the front mounted cleaner and the Tool Changer Extruder nozzle cleaners.  Finally, by having a “horizontal” brush, because where it mounts is fixed with relation to the nozzle, I'll be able to get several “wearings” out of the brush just buy moving it laterally before it will have to be replaced.So I settled on that one, for both my front Bed mounted “print start” nozzle brush and for these as well, thus having a single part to source for both applications.You can get these here:https://www.aliexpress.us/item/3256805063333961.html?spm=a2g0o.order_list.order_list_main.29.61e81802bu6GwI&gatewayAdapt=glo2usa FYSETC always has these in stock.  You can also get them from other sellers on AliExpress, Amazon, and several of the online 3D Printer parts resellers.  My guess is these will wear far longer than the “pencil stuff”, because instead of the nozzle passing through a few strands, with this block you pass through 3 groups of a bunch of strands.   The assembly consists of the Brush holder itself, and a “Keyed” side plate that locks the brush in place via a heatset screw and M3 bolt.Dead Nuts On, Every Time:Since the brush height is exactly the same from instance to instance, I've been able to CAD up the holder part to get the tops of the bristles to JUST hit the bottom of the socks if you have them installed.   They stick up 5mm over the extrusion, 1.5mm to the tip of the nozzle, and 3.5mm to reach the bottom of the sock.This will help keep the “gunk” off your socks as well, but isn't dragging into them so much that they'll get torn up.About the mounting:It mounts to the XL via the top rail 3030 extrusion just under the toolhead docks via T Nuts to the extrusion.   Now I personally abhor this style of T Nut: As they are very difficult to install, slide all over the place until you can get bolt into them, and are just (to me) too damn miserable to deal with.I far prefer the “shrapnel” style:  They are FAR easier to work with, and stay in place unless YOU choose to move them which makes getting them lined up with the bolts FAR easier than the other styles.   They are a bit more pricy though, and the SMALLEST M bolts you can use them with on a 3030 extrusion is a M4.   Small price to pay for the hassle saved.   However, you can use whatever you want.You can get the from a variety of places, I got a 50 lot of em for $13 from these guys: https://www.aliexpress.us/item/3256802822753306.html?spm=a2g0o.detail.pcDetailTopMoreOtherSeller.5.433e2540Yn5PXK&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40050.354490.0&scm_id=1007.40050.354490.0&scm-url=1007.40050.354490.0&pvid=b0b63bae-9c8a-4c46-89f3-6d07874a3aef&_t=gps-id:pcDetailTopMoreOtherSeller,scm-url:1007.40050.354490.0,pvid:b0b63bae-9c8a-4c46-89f3-6d07874a3aef,tpp_buckets:668%232846%238116%232002&pdp_npi=4%40dis%21USD%217.15%214.65%21%21%217.15%214.65%21%402103011417070717331904698e0b2d%2112000023209100052%21rec%21US%21131093321%21&utparam-url=scene%3ApcDetailTopMoreOtherSeller%7Cquery_from%3AParts you'll need (Per Brush Assembly):This will vary slightly depending on what you want to do in terms of the TNuts as described above.  If you go my route the per Brush BOM is:1 “Voron” style Nozzle Cleaning brush.  1x M3x4.2x3 or M3x4.2x5 Heatset Insert (for the brush “lock” plate).1x M3x8 Cap Head bolt (for the “Lock” plate)2x M4x12 Cap Head Bolt2x 3030 M4 “Roll In” Shrapnel FastenerPrinting details:You'll want to print these in PETG, particularly if you'll be running in an enclosure and printing any ASA, ABS or other high temp filamDue to the flanges these print in the same orientation they install in, brush insertion channel up. Note the use of PLA “Paint On” (not autogenerated) supports.   They are also used inside the nozzle “slot” to support the overhanging flanges.   I do these as PLA on PETG supports as well set to SNUG:For more info on that bit, see the Prusa article on this at:https://help.prusa3d.com/article/combining-materials-xl_498103These are all printed with PETG, 0.2mm layer height and the supplied PS file is for 0.4mm nozzles as my machine shipped after the 0.6 to 0.4 nozzle change.Support Removal:PLA on PETG supports with a designated extruder are for the most part utterly painless to remove, like in this case picking the part up leaves the PLA supports in place: The only “tricky” bit here is this is a fairly small part and the Flange supports (seen in place above, also in blue) result in full contact PLA on PETG supports (which is fine) but removal might seem intimidating.It's actually really easy.   Just wedge something between the support (on the side) and the vertical wall under the overhang to get the front edge of the support to come inwards, repeat for the other side and then just pull them out with a pair of needle nose.   The'll pop right out.  Likewise removing the support for the threaded hole on the Side “Lock” plate is just as easy, poke anything that will fit through a M3 hole from the other side of the lock plate and they'll just pop out.   I had 2 out of 5 come off just pulling the part off the bed.Heatset Insert Tip:Because of the side flanges for the T Nuts, the easiest way to set the cold stop on your heat insert press is just to stack em to set the stop point: I do this when cold (obviously) but wherever possible set a depth stop for the insert press to let it do the work.  Assembly:1:  Slide the brushes into the holder2:  Secure the brush in place with the “Lock” side plate (it's keyed).Note protrusion of the M3 Side Lock plate nuts: While the socket head is countersunk there isn't enough depth to completely submerse it.  3:  Pre thread the M4's into the flanges ( I CAD my stuff to have just a slight friction fit for this purpose to preclude the bolts falling out when installing things in tight places: 4:  Install all the T Nuts at once.  The beauty of the Shrapnel style T Nuts is they stay put and can be easily slid to where you want them during installation5:   Screw in on side of the assembly, skip a T Nut and install the next leaving them hanging: Once they're all hanging, just swing up the other end, slide the T Nut to line up with the bolt (which because you've pre threaded it will be easy to see, line up and screw in).Don't tighten them all the way up yet, just enough that the backside flange of the nozzle holder engages in the 3030's channel so the holder is absolutely parallel to the 3030 extrusion.  (V8 - Notch size adjusted).(Shown here as the orange bit surrounded by the selected blue face) 6:  Alignment and wear pattern:Since the holder is statically aligned with respect to the nozzle, you'll be able to get 3 “wearings” of the brush before you'll need to replace it:Left AlignedNozzle hits the middle of the 2nd row of bristles, thus covering the whole width of the nozzle   Right Aligned Nozzle his the middle of the 9th row of bristles, still covering the whole width of the nozzle.Middle Aligned (not shown)Nozzle hits the middle of the 5th row of bristles. The Surfalex2000 Tool:To do the alignment we'll be taking advantage of Surfalex2000's awesome nozzle alignement tool, which you can get here:https://www.printables.com/model/462473-prusa-xl-series-nozzle-scrubber-brush-update-inclu/filesIt's labled (as of the time of this writing) as "Nozzle Brush positioned" v5.3mf" in the models section. Working from left to right slide each nozzle brush to it's location “bristle row wise” as shown in step 6 to the location for each tools nozzle: And that's all there is to it.No gcode to maintain, no adjustments to make, and hopefully a very long 3 wear cycles before you'll have to replace the brushes, and when you do, because of the way the holder is designed, it's dirt simple to swap them out and not have to worry about any vertical adjustments or potential crashes.  File Stuff:I've included a STEP file (because STL's still suck), and a fully set up 3MF as slicer project file (these are always labeled (PS) to differentiate them form just a exported from CAD .3mf.  Enjoy.