ApolloLander Filament cutter - Prototype

Bambu labeled one, does include all the Bambu clone and Phaetus Conch hotend that all use the Bambu printed mount I made (updated the case with a 3rd clasping screw)

Dragon labeled one, applies to all the dragon style hotend, basically all the similar top mounted hotend on the Apollo (Dragon, Rapido, nextG, trianglelab hotends that are similar, Chube, etc)

As for extruder it's sherpa mini and orbiter 2.0/2.5 with rear motor (front motor will need a small tweak but should work, request it if needed)
May 2nd: added Orbiter 1.5 version (front/back motor)
and any extruder that has an adapter mount to fit the sherpa mounting pattern (i.e. APUS 2, etc)

Pre-requisite prints:

front mounted Linear rail apollo or mini only

new X tensioner (2025 model), 

and a tweaked front cover for it included here (one version is hammer secured with screw in plastic, other is heat inserts)

New chain holder if you use the X chain (included here)

not sure of the interference with the klack, but small tweaks would likely make it work in case there are issues.

has to reach approximately X=256mm on ender3 series (that's where the blade cuts, but a longer push rod or shifted hammer is an easy tweak if you want to cut it sooner). at that position my linear rail block is slightly off the rail but it's fine, not ball bearing exposed.

Hardware:

#11 blade (I got some cheap random Amazon one drenched in oiled paper, so don't recommend for the mess but gold standard are the X-Acto, X-acto Z, Excel and Fiskars brands)

(5x) 6x3 magnets, acting as a blade reset, instead of a spring or elastic. Currently testing some cheap Amazon ones, but a safer one would be those on Digikey, they are significantly stronger, only 2.5mm thick so will likely make a dedicated version for those, just to avoid rattling, but should work as is in the current design. I'm going to keep using the cheap ones to see if they are adequate enough.

(2x) M3x18~M3x20 to mount the extruder you'll need screw that are 12mm longer than what you were using, so likely M3x16 absolute minimum, but likely M3x18~M3x20

(7x) M3x8, one as the blade axle (socket or button) and three to close it up,
and three for the hammer (secured to the modded X tensioner)

(4x) M3 threaded heat insert, usual ones, 3 or 4mm long and 4.6 or 5mm outer diameter

Acting as a hard cutting surface:
M3 Din557 square nut (aprox 2.2mm thick, if you only have thin square nut aprox 1.8mm thick let me know as it will need a slight tweak on they model)

OR
common M3 hex nut (2.2mm thick), not tested but should work just as well

M3x6 button to hold the above square/hex nut (socket screw won't fit)

(2x) M3x12~M3x20, the longer the better, it's a very rough two point lever, one side doesn't screw in anything just slides in a moon shape cavity, so longer adds a bit of stability to the push rod, and other screw goes into a threaded heat insert, but must not be secured tight, actually should be loose, so longer the better.

Printed parts:

modded front tensioner

hammer

bottom case

top case

blade arm -> PETG or better

blade cap

Installation: it's really easy and fast I just broke it down in minute steps.

install heat inserts

swap the chain mount if you use one

swap the front piece of the tensioner case (two model included here, one screw in plastic other with heat inserts for the hammer. The tensioner clasping install using heat is inserts regardless)

install the magnet in the hammer

install matching magnet orientation in the push rod, so that they attract each other

install the hammer, M3x8 screws

pre-screw into the hole (screw in plastic but to lack of space) that will have the square/hex nut, then place the nut and screw the M3x6 button head, while avoiding the nut to rotate, should be tight-ish

install the magnet into the blade arm, orientation doesn't matter yet, other two magnets will have to match it.

install the blade into the blade arm, put the blade cap on, slides in the back first then lay down.

screw the blade arm, with an M3x8, do not tighten it just enough that it still moves easily ( case top will stop it from going anywhere, even if it unscrews a bit).

make sure the blade will be flush against the square/hex nut when in cutting position, and not sitting above it

you can manually test it's cutting capability which should work every time

Optionally this is where you can also try the blade setup with case open (using short M3 screw that secure where the extruder would be) you'll also need to skip to the push rod install 6 step below, the step in between require magnet install that can fly off, so best to do those magnet install away from the printer.
Then you see exactly at what coordinate the filament will be cut, home the printer, go to X=240, then move to the right 1mm at a time (was at x=256 on my setup, so you might need increase the X max in the config, and possibly slide the linear rail to the right a tiny bit, it's ok if the block stick out 5~6mm beyond the rail end). once done remove it from the printer (you can leave the push rod attached to the cutter, just a bit of gymnastic if you have cables on the left and chain holder in the way)

Place the other two magnets matching the orientation. 
So that on the cutting side the magnet pushes the blade arm away
and other side to catch the arm (both orientation will catch the arm from the blade steel, but matching the arm magnet will be stronger)
Magnets might try to fly off, so you can always try to place them on the case top (just don't confuse the magnet orientation )

close the case with M3x8 screws toward the back. and one front (don't secure it to the apollo yet, even though a couple holes look like it — those are just in case the top of the case can turn into an extruder adapter like a APUS 2 or LGX lite )

test the reset from the magnet to make sure it's good, and low friction on the blade arm (there is an access hole for the arm axle screw if you need to tighten/loosen that screw with case closed)

also test that filament can flow through, my multiple recent prototype were all working perfectly — if needed enlarge the hole with a small screw driver.

place the push rod behind the Apollo sliding under the cable chain holder and in front the chain if you have one

place the filament cutter on the apollo top and secure the blade arm to the push rod with two long screws, M3x16 to 3x20. Don't over tighten the screw that goes into the the threaded heat inserts, this needs to rotate easily.
You can easily install this before putting it on the apollo as well, but if you have cables coming out on the rear left vertical cable channel, it may be easier to do it after.
There is a lot of play here but seems to be fine. But that is one area that I want to try and improve.

test the mechanism manually again, it should/must reset itself from the magnetic force. Check for any other issue and report those to me please, the chain does add bit of drag to the push rod but was low enough on my setup

install the extruder
 - outer holes are for the sherpa mini
 - inner holes are for the orbiter2.0 rear motor

to cut filament you just have to go to the cutting coordinate, you can increase the cutting chances with a double hit, just moving back 5mm or so between hits

the rest, like filament change is beyond the scope of this post, but my discord server is a good place to figure things out.