Mechanical Engineering
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3D Printed Soft Robotics Fingers
I worked on a team of five to design a series of polyjet printed soft robotic fingers as part of an Additive Manufacturing course. The fingers work pneumatically to bend like a human finger. These fingers could be used as soft grabbers that can manipulate complex shapes or other soft materials. We created the three fingers to the left to test deflection. I designed finger A, which turned out to be the most effective finger.
The fingers bend due to their material and geometric asymmetries. The top of each finger has much more surface area than the bottom and is made of a flexible material. The bottom is flat and contains segments of non-flexible material. When pressurized, the top expands, while the bottom does not. This causes the finger to bend.
I simulated the deformation of each finger using large deformation FEA in order to predict the relative deflection of each finger.
In order to optimize the finger that I designed, I characterized different parameters as seen above. I changed the dimension of each parameter and ran large deformation FEA on each value to determine the total deformation. The relative change in deformation can be seen above. I then set the dimensions that resulted in the greatest deformation to the final finger.
The fingers were then manufactured using a Polyjet printer with two types of plastic (stiff and flexible). Since the inside of the fingers were hollow, they were full of support material after printing. In order to remove the material, we flushed water through the inlet port, which brought the support material out through the many holes we designed into the parts. Once support material was flushed, we plugged the holes with glue for testing.
We tested the fingers by pressurizing them until failure while we recorded the results. These results are shown to the left.