J-04 – Articulated Companion Robot

Compact articulated companion robot with snap-fit joints and expressive poses.
No glue, no screws, no tools — just print, snap, and pose.

Designed to be simple to print, fun to assemble, and full of personality once finished. 

Printing Instructions

This model was tested using the included print profile for the cleanest results and optimal joint tolerances.

Standard scale (100%) works directly with the main profile.

For scaled prints (150%, 200%, 250%), use the corresponding “Adjusted Axis Fit” print profile.

Only the axis parts need to be reprinted when scaling to preserve joint stability.

If you prefer to use your own settings:

• Layer height: 0.2 mm
• Walls: 3
• Top / Bottom solid layers: 6
• Infill: 5% Gyroid  infill
• Supports: Not required

All parts come pre-oriented for reliable, hassle-free printing.

 
Note: Scale profiles contain only axis parts, not the full model.
  

Material Notes

This model was designed and tested using PLA.

Other materials may work, but flexible filaments such as PETG can result in looser joints. 
For best results, it is recommended to print all joint and spring (Plate 3) parts in PLA.

Good flow calibration is important due to the small size and tight tolerances of the parts.

Bed Adhesion

The model prints reliably on clean build plates.
It was tested successfully on Cool Plate, Smooth PEI and Textured PEI surfaces.

Make sure the build plate is clean and free of oils.
A clean surface is usually sufficient — no brim is required.

Assembly

• Snap-fit assembly.
• No glue, no screws.
• Follow the visual assembly steps shown in the images.

Tip - Assembly Fit

If assembly feels harder than expected, check your Flow Ratio calibration.

This model uses tight tolerances, and slight over-extrusion can make parts harder to snap together.

• If parts feel too tight
  → reduce the Flow Ratio by about 0.05 (for example from 1.00 to about 0.95)
• If parts feel too loose
  → increase the Flow Ratio by about 0.05 (for example from 1.00 to about 1.05)

In most cases you only need to reprint the metal parts (Plate 3) after adjusting the flow.

See the reference image in the gallery (last picture) showing where to adjust Flow Ratio in Bambu Studio. 

Tip - Leg Lock Assembly

The leg locks can be a bit tricky to insert due to the small manipulation space.
Hold the robot sideways and use the body wall as support to push the lock straight into place.

Make sure the leg is in the correct position before inserting the lock (see animation).

Description

J-04 is a compact articulated companion robot designed to feel expressive, solid, and satisfying straight off the print bed. Every joint was carefully tuned to balance smooth movement with reliable friction, allowing the robot to hold dynamic poses without feeling loose or fragile.

The design is fully snap-fit, requiring no glue or hardware. Assembly is intuitive and fast, guided entirely by visual steps. Once assembled, J-04 behaves like a single cohesive object rather than a collection of loose parts.

Customization is a core part of the design. You can mix and match colors across the head, feet, and accents to create unique personalities, from clean monochrome builds to playful multicolor variations. Whether displayed on a desk, shelf, or used as a poseable companion, J-04 adapts easily to different styles and environments.

This model was designed to be enjoyable at every stage — printing, assembling, posing, and displaying — while remaining accessible to printers of all experience levels.