Have you heard of Crush Ribs?

Crush ribs are a great way to stop tweaking files per-printer and still get that snug fit you need for good mechanisms. Here’s a short video explaining the why, the where from, the how, and more.

Also, here’s a follow up tip about how to make crush ribs draft quick fast.

Did that help you? Did you use it in a design? Let me know so I can share it with everybody.


Sixi Robot Gripper Design Adventures

I thought that the hard part would be making the Six robot arm. Turns out making a two finger gripper is also pretty challenging! I would love to see students take on this challenge to make their own gripper. There’s so many ways to tackle the challenge.

Gripper requirements

The gripper must:

  • Attach to the ISO 9409-50-1-M6 hand
  • Have two fingers
  • Weigh under 1kg
  • Be able to pick up at least 1kg and turn it arbitrarily without dropping it
  • Not crush soft objects like grapes, eggs, or empty cans
  • Have a minimum stroke (movement distance) of 30mm.
  • Run at 12v (max 2a) for motor power.
  • Run at 5v (max 500ma) for logic.
  • Have replaceable fingers that can be customized to different tasks

It would be nice if

  • The gripper would use ModBus (RS485) to communicate with the Sixi robot.
  • The gripping strength could be controlled by the robot.
  • The robot could tell the state of the gripper: position, activity right now, etc.

More to follow as this adventure unfolds! Wish us luck.

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Robot Arm

A Sixi Robot cycloid gearbox eccentric cam shaft

An eccentric cam shaft is at the heart of our cycloid gearbox. Any force acting on the gearbox is focused at this point. So it makes sense that a good gearbox has a super strong cam shaft. This design is made to connect on a motor with a 1/4in diameter shaft, which happens to be the same as the NEMA23 motor in the elbow of the Sixi Robot.

Want to practice your CAD skills? Try making a 3D model of this part, yourself. Tag us on social media if you do!

Here it is inside the gearbox.