Molding Silicones and Urethane Rubbers

A project log for Wearable, Soft Robotic Exoskeleton Gloves

The New Dexterity / Open Bionics wearable, affordable, soft exogloves are bionic devices for rehabilitation and human augmentation.

Lucas GerezLucas Gerez 10/01/2020 at 21:550 Comments

3D Printing Components

The rigid parts and molding components of the glove are produced through 3D printing, and are
printed in PLA or ABS plastics.

Mold Assembly

Depending of the module being fabricated, the mold assembly steps can vary from preparation of a
single mold part, to the assembly of several mold components.
Before Assembling the components of the mold together spraying the inside of the mold with mold
with mold release can greatly ease in the effort required during the demolding process.
The mold release we use is EASE RELEASE MANN 200 FOR SILICONES & RESINS.

Filling Molds

Once a mold is assembled, the selected elastomer material is mixed together following the
manufacturers guidelines and then degassed to remove any air bubbles, which can leave unwanted
cavities in the molded part. When the mixture is complete it is deposited into the mold cavity,
where the mold release was also sprayed.

The chosen elastomers we used to produce the laminar jamming finger pouches, layer jamming material, and telescopic thumb were Dragon Skin 30, and Vytaflex 40. The 2 materials both had a 1 to 1 mix ratio. For more complex parts like the telescopic thumb, which uses a multi-mold process the ‘3D Printing’, ‘Mold Assembly’, ‘filling Mold’, and ‘Mold Disasembly’ steps need to be repeated to mold the different parts together. An Image of the molding steps of the telescopic thumb can be found below. 

An example of mold mixing can be found in the video below.

Mold Disassembly

After the curing process is completed, the molded components can be removed from the molds and
assembled together with the other 3D printed parts and the glove.