OutFox Zero Clog Multi-Material System (Ender 3 series) by The__Captain

Last crawled date: 3 years, 3 months ago

Outfox those persistent clogs in your multimaterial/multicolor printer!
The OutFox multimaterial system is a unique (to my knowledge) approach to eliminating clogs in a FDM bowden system that uses a 2-to-1 (or any X-to-1) adapter.
https://www.youtube.com/watch?v=WRMeYPNUrjs
The primary innovation is an inline filament cutter that alleviates the need to retract hot, melted filament from the hotend in order to swap colors/materials. Instead of retracting existing hot filament in order to swap in a new color/material, the filament is cut between the X-to-1 adapter and the hotend. Only then is the old color/material retracted, leaving a segment of old color/material in the hotend. At this point, the new color/material is extruded, pushing out the old color/material through the hotend. This completely avoids the potential for clogging as a result of retracting hot, melted filament from the hotend because hot, melted filament is never actually retracted from the hot end at all.
This modification requires an additional axis (i.e. stepper) to drive the linear actuator which in turn opens and closes the jaws of the inline cutter. How to add another stepper to your machine is beyond the scope of this documentation. Please refer to your manual, local support group, google, etc
The printed parts are many, but none take much more than an hour to print other than the Main Shroud, and some take only minutes.
Aside from the printed parts, you will need:
2 Nema17 steppers. The more torque, the better
1 Extruder. I like BMG clones from Biqu. I would recommend you match your new extruder with your existing extruder
1 M8x1.25x60 (or longer) hex head tap bolt (Note that this is a FINE pitch bolt)
1 M8 fine pitch hex nut
2 M5x50 (or longer) hex bolts
6 M5 nuts
1 Spare 20mmx8mm bed leveling spring (stock is good, yellow springs may be too stiff)
1 Chisel razor blade (37mmx6mm)
1 Bicycle brake cable
2 Bicycle brake cable knarps
2 5mm bowden (push-connect) fittings. (The kind that does NOT permit the tube to pass through)
1 Length of bowden tubing (250mm to 300mm, or enough to reach across your print bed and then some)
2 10mm bowden (push connect) fitting. (The kind that DO permit the tube to pass through)
2 Lengths of bowden tubing (enough to reach from your top rail to your hotend, and then some).
1 Small length of bowden tubing (~80mm)
1 5015 fan
7 M3x10mm screws
2 M3 nuts
2 608 (i.e. skate) bearings
1 twist tie
1 stock extruder hob
2 long stepper cables
Construction
Printed parts are capitalized for easy identification
Almost all holes and cutaways are sized towards the small side, upon the logic that it is easier to spend a few minutes reaming or sanding a tight fit than it is to re-print an entire piece because it was too loose.
Linear actuator assembly
Attach Actuator Cable Adapter to hex head of M8 fine pitch bolt
Insert M8 fine pitch bolt through Actuator Idler. Actuator Cable Adapter should be between the "arms" of the Actuator Idler.
Insert M8 fine pitch nut into Actuator Large Gear
Insert M8 fine pitch bolt through 608 bearing
Screw Actuator Large Gear onto M8 fine pitch bolt. The hex head of the bolt should be on the opposite side of Actuator Large Gear from M8 fine pitch nut.
Insert M8 fine pitch bolt through 608 bearing
Insert M8 fine pitch bolt through Actuator Base Plate
Insert M5 bolts through Actuator Idler
Add two M5 nuts to each M5 bolt
Insert M5 bolts through Actuator Base Plate
Add M5 nut to each M5 bolt. Tighten all M5 nuts.
Push stock extruder hob into Actuator Small Gear
Attach Actuator Small Gear to nema17 stepper
Trim brake cable to size (~100mm longer than first length of bowden tubing in parts list).
Insert brake cable end into Actuator Cable Adapter
(Optional) If brake cable end does not does not fit inside Actuator Cable Adapter, remove existing cable end and replace with cable knarp
Attach (screw in) 5mm bowden connector to Actuator Idler Plate
Attach Actuator Idler Plate to Actuator Idler using M3 screws
Cutter assembly
Attach Cutter Arm to Cutter Base using Cutter Screw
Insert chisel blade through Cutter Arm, secure with twist tie
insert brake cable through Cutter Base, then through bed leveling spring, then through Cutter Arm
Close Cutter Arm so that the chisel blade is barely visible inside the Cutter Base tubing path. There should be a small amount of compression on the bed leveling spring.
Attach cable knarp to end of brake cable.
Y Adapter assembly
Chamfer both lengths of bowden cable using Chamfer Cutting Guide
Insert one length of tubing into one of the "arms" of the Y adapter until it reaches the internal junction
Insert a razor blade into the slot in the Y adapter, and slice off the side of the inserted tubing.
Remove the length bowden tubing
Repeat previous three steps with second length of cable, using the other "arm" of the Y adapter
Insert both lengths of cable into the Y adapter. They should meet and join perfectly inside the Y adapter (visible from the bottom). Retrim both lengths of tubing if necessary until they can be joined perfectly inside the adapter.
Remove both lengths of tubing
Screw in 10mm bowden connectors to the "arms" of the Y adapter.
Reinsert both lengths of tubing into the Y adapter, confirming once again that they join together perfectly
Attach extruder steppers to Extruder Mounting Adapters
Connect tubing lengths from Y Adapter to extruder steppers
Mount Extruder Mounting Adapters to top rail.
Preliminary Testing
Unload filament
Remove stock shroud and fans
Replace parts fan with 5015 fan [wiring]
Unmount extruder from gantry
Mount cutter stepper and linear actuator assembly to gantry using old extruder mount point.
Insert a scrap piece of bowden tubing into Cutter Base tubing path
Insert a scrap piece of filament into the scrap bowden tubing from previous step
Connect all steppers and turn on printer
Enable cutter stepper and issue a command to retract and feed ~190mm. The linear actuator should pull down the Cable Adapter, causing tension on the brake cable, eventually causing Cutter Arm to cut through the tubing and filament. If your stepper skips or bogs down, you can try adding lubricant to the linear actuator drive bolt, upping the stepper current, disabling StealthChop, getting a better stepper, etc, etc. You can also adjust the cable knarp that sits against the cutter arm if the filament is not getting cut (cable length is too long), or the cutting blade blocks the filament path (cable length is too short).
Completion
When the previous step can be repeated successfully to your satisfaction, attach Main Shroud to printer carriage using two existing stock shroud screws
Attach stock fan to Main Shroud using stock fan screws
Attach Bullseye Fang to Main Shroud using M3x12mm screws
Fully insert short bowden tubing length into hotend bowden coupler
Test tubing length by inserting Y Adapter into socket on top of Main Shroud. Trim tubing until Y Adapter can be fully inserted into Main Shroud, but trim it NO SHORTER.
Remove short tubing length from hotend.
Mount Cutter Base to Main Shroud using M3x10mm screw
Insert short bowden tube into Y Adapter Plug. Leave ~10mm of tubing extending through Y Adapter Plug
Fully insert short bowden tubing length through Main Shroud from above, through Cutter Base tubing path and into hotend bowden connector.
Insert Y Adapter into socket on top of Main Shroud, and onto short bowden tubing length
Secure Y Adapter to Main Shroud using M3x10mm screws
Raise Y Adapter Plug until it rests fully inside Y Adapter.
Attach 5015 fan to 5015 Adapter 90deg
Attach 5015 Adapter 90deg to Bullseye Fang using stock parts fan screws