January 5, 2025
Description
Fully printed, no assembly, print-in-place fin ray grippers, printed with plain PETG, no TPU flexible filament needed.
The connectors are compatible with fischertechnik. The grippers' angle is 16°, so that you can use two Winkelsteine 7.5 to get a near parallel setup.
Dimensions: 78x30 mm, 7.5 mm or 15 mm height. Use the versions with custom brim for better bed adhesion.
You'll need a well calibrated printer/filament combination. Elephant feet, stringing, and particularly overextrusion will result in joints which are not supple enough for a smooth operation.
Post printing: Clean the joints from filament remains and gently break them loose. You can improve suppleness by manually bending each joint individually with one hand a couple of times while gently pressing it together from above and below with the other hand.
I increased the grippers' insides' grip with vulcanizing fluid used for bicycle repairs. You'll need a couple of coatings, which is easy as it dries very quickly (don't inhale the fumes). There are probably better alternatives like spray on rubber, if you have them.
I had no success with printing a durable version with PLA, they always broke after a bit of use. Maybe Tough PLA and similar filaments might be an alternative. Make sure to comment if you made a working version or, even better, post a make.
The servo driven gripper base is from my SG90 mini servo system.
License:
Creative Commons - Attribution - Non-Commercial - Share Alike
juh
