Add3d - Adjustable Replicator 2 Drive Block
An adjustable drive block for MakerBot Replicator 3D printers or machines with similar Nema 17-based extruders. Note: For replicator 2X we recommend this part.
A knob fitted to a screw applies adjustable pressure on the axial bearing against the filament and drive wheel. This is an experimental mechanism for fine-tuning the extrusion of different kind of plastic filaments.
This design doesn't need a metal spring and relies on the flexibility of the lever. Alternatively, it can use a rigid lever and a small piece of rubber compressed by the M3 x 35 mm crew. It has been successfully tested on the 3D printer models, Replicator Dual and Replicator 2.
See the image with coloured parts above for reference. The shipped version of the product has all parts 3D printed in black plastic with exception of the knob which is red.
Base plate - Base structure which holds the lever, provides filament guidance and support for the adjustment screw. It is attached by two M3 screws to the front face of a Nema 17 motor. (3D printed part - Black in the reference image above).
Lever - Holds a small axial ball bearing and presses it against the 3D print filament which rests against the stepper motor's metal drive wheel. The lever also holds an M3 Nylock nut and the adjustment screw. (3D printed part - Yellow in the reference image above).
Cover - Lid which fits in the left part of the lever and covers the ball bearing. (3D printed part - Blue in the reference image above).
Knob - (Top part) - Mounted with a drop of glue to the head of the M3 x 35 mm adjustment screw. (3D printed part - Red in the reference image above).
Knob - (Bottom part) - Mounted with a drop of glue to the lower face of the knob and fixates it to the screw head. (3D printed part - Red in the reference image above).
Allen bolt M3 x 16 mm - Fixates the cover, lever and base to the front face of a Nema 17 motor. (Fits the top left threaded hole of the stepper motor).
Flat head cap screw M3 x 6 mm - Fixates the base plate to the front face of a Nema 17 motor. (Fits the top right threaded hole of the stepper motor).
Nylock nut M3 - Placed inside the right tip of the lever. It transfers the force of the adjustment screw to the lever.
Screw M3 x 35 mm - Placed through the M3 Nylock nut and applies adjustable force to the lever. The knob is attached to the head of this screw.
Ball bearing 4 x 10 x 4 mm - (Inner diameter x outer diameter x width) - Placed on the small post in the lever. Applies force to the filament.
The following tools and materials are needed to assemble this kit.
- 2.5 mm Allen key
- Screw driver (flat-blade and Philips)
- 5.5 mm fixed spanner or adjustable wrench
- Super Glue
- (Optional) Loctite Threadlocker. Use a small drop on the M3 x 16 mm and M3 x 6 mm if you want to make sure they remain tight. It is important that you use weak threadlocker so that you can remove the screws in the future. This is an optional step which is usually not necessary.
This kit contains all parts listed in the "Component description" above. The 3D files for the plastic parts can be downloaded and used free of charge from Thingiverse through this link. Note that the Nema 17 stepper motor seen in the images above is just used as reference, it is not included in this product.