Shape setting configures the transformational and mechanical properties of shape memory alloys, particularly Nitinol (Nickel Titanium). A machined NiTi component is mounted on a special jig or mandrel and then inserted into the furnace for heat treatment, which sets the shape. STI designs and manufactures these mandrels and special jigs according to the exact specifications of the product.
Good bio-compatibility combined with shape-memory and super-elastic capabilities makes Nitinol the material of choice for a wide variety of medical devices, e.g.: Stents, endoscopic and arthroscopic tools, anastomotic devices, guidewires, and embolic coils.
Self-expanding stents, for example, use the stress-strain behavior (stress hysteresis) exhibited by super-elastic Nitinol to exert low chronic outward force on the walls of the target vessel thereby keeping it open while resisting external deformation (crush and kink recovery).
STI optimizes the shape setting process per each product according to the specific mechanical properties required by the product. Shape setting procedures involve several heat treatment steps run in succession. The number of steps and exact heating and cooling profile depend on the original dimensions (as cut), the final dimensions of the part (as specified) and the desired 3D geometry. The last step fixes the final shape of the component.
STI uses state of the art equipment to induce specific thermal cycles of NiTi from austenite (As, Af temperatures) to martensite (Ms, Mf temperatures) using controlled heating and cooling processes respectively (≤ 700°C). STI adjusts the entire process to meet desired Af temperature and RF values within small tolerances and with highly repeatable results.