Bondtech Prusa I3 MK3S Extruder upgrade

Bondtech Prusa I3 MK3S Extruder upgrade

Regular price $ 110.00 USD
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Bondtech Lightweight Upgrade Kit for Prusa i3 MK3S


X-Carriage Upgrade is Required for this upgrade it is not included.

Or you can print your own using these links.



The Bondtech Upgrade Kit for Prusa i3 MK3S is a lightweight high-resolution extruder dedicated to improving performance and reliability of this iconic Prusa 3D printer model. Its optimized design was achieved with the help of the Prusa community.

Upgrade Your Extruder
Increase the gear ratio of your extruder to a 3:1 that will deliver extra push force and higher resolution.

Print Faster Or Better
With this lightweight extruder that saves 15% of the weight of the parts replaced, it is possible to 3D print faster or to improve the surface quality when printing at the same speed.

Reduce 3D Printing Issues
Improving material extrusion will decrease the risks of encountering 3D printing issues. Avoid heat creep and reduce clogs. Get a regular and precise material feeding with no slipping neither filament deformation to minor under and over extrusion caused issues.

Upgrade kit With Optimized Design
The Bondtech for Prusa i3 MK3S is the latest upgrade kit from the Swedish manufacturer that incorporates all improvements achieved with the help of the Prusa community.

Bondtech Extruder For Prusa i3 MK3S
This kit contains all the parts needed to convert your printer's extruder to the popular Bondtech BMG (Bondtech Mini Geared) based design. Its 3:1 ratio increases the accuracy and resolution of material extrusion. Its carriage printed with PA12 by the SLS process and with updated geometry optimizes the hotend’s heatsink cooling.

Lightweight BMG (Bondtech Mini Geared)
This upgrade saves 15% weight of the extruder. This reduction will have meaningful impact on the moving weight and vibration thus lowering the ghosting effects.

Product Main Features

  • This extruder upgrade kit fits the Prusa i3 MK3S, and other Prusa i3 models upgraded to MK3S.
  • Here are its main features:
  • Fits Prusa's new filament sensor;
  • Upgrades the extruder to a 3:1 gearing ratio;
  • Heat-sink cooling optimized geometry;
  • Lower moving weight reduces vibration and ghosting;
  • Housing 3D printed with PA12 using SLS.

What’s in the Box

  • 1x Extruder housing with Hinge, Hinge shaft, and main shaft assembly.
  • 25mm pancake Stepper Motor
  • Extruder Motor cable in a plastic bag
  • Screws and nuts in a plastic bag
  • Powered by Bondtech sticker
  • 5x 3D printed parts
  • 5x Zip Ties

Reducing 3D printing Issues
The new housing design improves the heatsink cooling and lowers heat creep issues that are associated when all metal hotends print with PLA. This enhancement is meant to avoid PLA clogs.
The higher push force drastically reduces slipping, shredding and filament deformation and works to avoid the common filament 3D printing issues that are caused by under and over extrusion.

Updating the Firmware
To use this upgrade in the MK3S, there is a need to update the firmware. The e-steps value must be updated to 830.

Additional Information

 Stepper Motor
Lightweight 25 mm pancake stepper with 18 N/m torque.
Max Input Current : 0.8A
Max chamber working temperature : 80℃

 Weight Reduction
343,2g of parts coming out and 291,5g of parts coming in. A 51g (15%) weight save.

X-Carriage: Requires buying or 3D printing new X-Carriage R2 Front and Rear;
Firmware: Bondtech adapted version required.

Technical Datasheet
Article number : EXT-KIT-68
EAN code : 7350011410651
Net weight : 291,5g
Gross weight : 380,2g
Package Size : 137x94x65mm
Gearing ratio : 3:1
E-steps value : 830
Extruder Housing: SLS Printed parts in PA 12;