PCI Method: A Novel Fabrication Method of Soft Mechanisms Utilizing Cure Inhibition of Addition Reaction Silicone

Abstract

In this paper, we propose a novel fabrication method of soft mechanisms, which positively utilizes cure inhibition of addition reaction silicone. Cure inhibition occurs for instance if the silicone is cured in a mold containing a certain substance, and then the silicone remains in a liquid state without curing at the boundary with the mold. Thus, cure inhibition is generally thought as undesirable phenomenon. Our method intentionally induces the phenomenon to realize a flexible joint mechanism that can be smoothly rotated in the primary rotational direction and also be adaptively deformed in the other directions. We found that a sub-millimeter thick layer of cure inhibition was formed when we cured an addition reaction silicone in a mold made with an ultraviolet curing type 3D printer. We experimentally investigated the characteristics of the occurrence of cure inhibition, and proposed two patterns of fabrication methods of joint mechanisms by utilizing the cure inhibition. The evaluation results showed that the joint mechanisms had properties suitable for constructing adaptive robotic fingers and other soft robots.