Mold

Overall Design

The mold design showed below is for the main body of the hand which will be filled with polydimethylsiloxane. During the first iteration, we made molds of each of the fingers and tried to combine the solidified polydimethylsiloxane(pdms) from each of the molds together into the hand, but that didn't work. So we decided to design a single mold of all the fingers.

Each finger has extruded pieces for making channels and chambers, with extruded long lines for air channels being connected all the way to the end of the hand, where they will be connected to the pipes and pump. It is important for the air channels to be high enough (at least a quarter of the total height of the fingers) for smoother actuations.

The file for printing the mold was made using SolidWorks. The STL can be downloaded on this page.

Braces Using Later Cutting

After the mold was printed, we added 'braces' in each finger to separate each of the chambers and to facilitate actuation. The 'braces' were made by drawing 0.44' x 0.20' rectangles with the CoreIDRAW X5 and laser-cutting 2 mm thick Poly (methyl methacrylate) (acrylic) sheets with the Epilog Laser Mini. 

More details are described in 3) Fabrication- Step 2