SDGX - Small dual gear direct drive extruder for Ender 3 - Work in Progress

WORK IN PROGRESS 

This is a custom case for bondtech BMG gearset designed to offer the shortest filament path possible with using the stock ender 3 hot end making it a great low cost setup for printing flexibles. It eliminates bowden fittings, instead the bowden tube has a seat inside the extruder to keep it pushed against the nozzle. Build plate volume is only reduced by 2mm in the x direction. V1 cooling package reuses stock ender 3 fans. The case has mounting holes for different cooling packages which might come later. 

__________________________________Required non-printable parts____________________________________________

2x M3 nuts

3x M3x40 countersunk screws - for mounting the stepper motor

1x M3x30 stud - for mounting the hot end and extruder to the carriage

1x M3x30 screw - for mounting the hot end and extruder to the carriage

4x M3x8 screws - for mounting cooling package

1x M3x40 thumbscrew - for tensioner arm

stock ender 3 fan mounting screws

BMG gears, lever, spring, bearings, pins

_____________________________________________ASSEMBLY_____________________________________________________

For assembly follow exploded view - note that since the large gear of the extruder stick down you will have to prepare an M3x30 stud, bolt it into the left hole on the carriage and then as you slide the hot end and extruder on it insert the nut behind the gear, the screw on the right can be inserted afterwards like standard. Also note that you will need to cut your ptfe tube correctly so that it pushes against the nozzle and the seat inside the extruder

_______________________________________________PRINTING_____________________________________________________

Material - PETG for case 1 is mandatory, for any other parts you can experiment with PLA but i would recommend PETG for all the parts

I printed it with 4 walls and 3 top layers with 20% infill. 

disclaimer its up to you how you orient the parts, dont print them in the orientation they come with, they are flipped, thats how my cad exported them

Case 1 needs to print with supports around the overhang for the lever and hot end, no need for supports in the screws holes and the fillament path so use support blocker. This part might need a bit of cleanup but tolerances were fine in my case.

Shroud and duct will also require supports depending on how you orient them.

Fan shroud might require to be clearanced for the bottom roller nut, depending on which way the screw is facing on your printer. This will be fixed eventually.

________________________________________________________________________________________________________________

Please leave your feedback if you decide to try this extruder so i can improve the design and work out any kinks. I have so far put roughly 15 hours on it printing 95A TPU without any problems. Also leave any ideas which you might have down in the comments. And lastly if you want to contribute or remix the design in any way please message me through comments so i can provide you STEP files.