NSTT Extruder by Paciente8159

Last crawled date: 3 years, 1 month ago

This is the NSTT Extruder. (Revision 3 now available)
I've designed this extruder in December 2016 and after some heavy testing and redesigning I decided to share it.
NSTT stands for "Not So Tiny Titan" and is an E3D Titan inspired printable extruder. Despite the name it is a pretty compact geared extruder when compared with other geared extruders.
It has the same 3:1 gear ratio as the E3D Titan.
It incorporates parts from my initial MK8 extruder like the spring, the hobbed gear and the 623z bearing.
To built this is necessary:
-4x M3x10 screws and nuts
-1x M5x40 screw (Hexagonal head) a M5 nut and an M5 nylon lock nut
-5x M3x25 M3 screw and nut
-1x M4x20 screw (internal hex head) and nut
-2x
option 1-625ZZ bearings (needs 1xM5 washer)
option 2-688ZZ or F688ZZ bearings (no need for washers)
-1x 623z bearing and a M3 washer
-1x MK8 hobbed gear
-1x MK8 tension spring
-1x extra 625z if using idler+body B
This extruder has hundreds of hours of work and it has been my extruder for the last 3 years. There are also a couple of variations of my design like the Drakon and the Pitan extruder that you can also check.
Update
06-08-2020
Following hellriser design, added 2 new parts for an optional assembly that includes a small gear with an higher side to fit a screw that locks the gear on the stepper shaft and the matching adapter base. This was not tested.
Update (revision 3)
14-05-2020
Revision 3 of the extruder is now available. Here are the changes
Added thickness around the idler screw on the body to avoid cracking due to the preassure of the string.
The lit also covers the screw to ensure it does not jump out of place.
Update (revision 2)
16-07-2017
Revision 2 of the extruder is now available. Here are the changes
New extruder lit that will offer support to stress caused by the idler spring tension that causes cracking on the top of the body near the outer bearing.
New assembly option for the idler main shaft. This allows for the using of the stepper shaft has the idler shaft has the initial version of the extruder.
New filament coupler design to prevent miss-alignments.
Included the stepper motor adapter sketchup file so you can modify/adapt the support to any given stepper or support on your printer.
Update (revision 1)
17-04-2017
New body that features a side window to allow tightening/cleaning of the hobbed MK8 gear without the need to disassemble the extruder.
Added a teflon tube insert/holder on the input side of the feeding system.
Supressed the need for 625ZZ bearings on the filament idler (lighter)
Redesigned gears. Easier to print and fit/match on assembly.
New option for bearing usage on the M5 long screw that allows better performance/less trouble. 688ZZ or F688ZZ can be used by using the available spacers. This also eliminates the need of using washers in the main axis (washers are hard to center/align).
New stepper mount plate to accommodate new gears
Update
09-02-2017
added filament guide on the extruder body (filament input side). Although the MK8 hobbed gear keeps the filament in the right track the filament can skip from the 623zz bearing and get stuck outside the gear causing the print to fail. The new filament guide prevents this.
Assembly
Instructional video here:
New Revision 2 - https://youtu.be/ww7HrSxefLU
Original version (outdated) - https://youtu.be/Cpo0SOepOIE (outdated)
Insert the small gear in the stepper shaft. It will self lock.
Put the M3 nuts in the motor mount base and screw the motor mount to the stepper (M3x10).
Pick up the M5x40 screw and insert in this order:
For the 625 bearings (option 1)
Big gear
M5 washer
625 bearing
625 spacer A
MK8 hobbed gear
For the 688 bearings (option 2)
Big gear
688 spacer A
688 bearing
MK8 hobbed gear
Mark were the side screw is hits the M5 screw remove it all and use a tool file to make a dent in the M5 screw. Reassemble all and tight the MK8 hobbed screw in place.
Connect the two printed gears and insert the extruder body, fitting the bearing in the main body slot. Some adjustments to the position of the small printed gear in the stepper shaft may be required to allow correct alignment. Screw the extruder body to the base (M3x25).
Assemble the filament idler. If using body+idler option B insert the 625 bearing in the idler. Insert the M3 nut on the back of the idler. Insert an M3 washer then the 623 bearing (washer is on the nut size and the bearing is on the side of the screw head) and screw the bearing ans washer in place (M3x10).
Screw the M4 nut on the M4 screw and place the MK8 tension spring in the M4 screw. Place it as the pictures shows (back side of idler)
Fit the idler in the stepper shaft.
Place the filament guide in place.
Screw the extruder lit in place. Insert the rest of the shaft parts by this order:
For the 625 bearings (option 1)
625 spacer B
625 bearing
M5 nut
For the 688 bearings (option 2)
688 bearing
688 spacer B
M5 nut
Tight all with the M5 nut (use your fingers). You want it to tight it very mildly so it wont load the bearings too much. Insert the M5 nylon lock nut on top of this.
Note: The MK8 hobbed gear has very shallow teeth and not very sharp to avoid deforming the filament. In my case I have to apply a considerate amount of force to the tension sprint to avoid filament slip. I unscrew the M4 nut half way (see main picture).
The rest is up to you. Either use the E3D in direct feed mode or print the adapter (two halfs) to install the pneumatic coupler to use it has a bowden extruder.
In Marlin configure the E steps/mm to about 440. Test it and adjust.
Enjoy your new geared extruder. The printing quality on this is worth it!!!