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Actuators - Fabrication updates

A project log for Affordable bionic prosthesis

This project aims to create an affordable lower limb prosthesis for above knee amputees using hobby grade components.

maximiliano-palayMaximiliano Palay 05/17/2022 at 19:110 Comments

I'm dropping a few pictures from visits to the machinist.

The design required the stock 1204 ball screws to be cut down to proper length, and an M8 thread was machined on one end of each. Furthermore, rod ends were adapted to restrict the ball joint to a uniaxial rotating joint with bearings. Originally, newly fabricated rod ends were on the plans. But the machinist offered to modify existing ones which would simplify the fabrication and reduce overall costs.

First visit to the machinist.
First visit to the machinist. The original rotors are covered in tape to protect them from scratches. These already have the center bore and the four holes for mounting the ball nut. At the top of the image, the ball screws are shown already cut to length and threaded. Parts of the 3D printed prototype can be seen with a navy-grey color. Some aluminum parts with progress pending can be seen as well.
Partially assembled rotor.
The modified rotor with the new axis press fitted can be seen at the left of the image. The angular contact ball bearings are over the rotor. At the top right, the modified stator with the original bearing seats removed, and the new aluminum piece fitted inside. This piece was glued with anaerobic cement. At the bottom right, the crown.
Modified rod end.
One of the modified rod ends, without bearings. The original ball joint was removed and two bearing seats were machined from aluminum and press fitted into the original rod end casing.

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