Development of Actuators Using Material Extrusion Additive Manufacturing with Embedded Shape Memory Alloy Wire
Over the past several decades, the advancements in Additive Manufacturing (AM) technologies have opened a wide variety of applications where AM can be used. Some examples of these advancements are the introduction of automatic wire embedding capabilities, the introduction of multi-material processing and the printing of thermoplastic elastomers. With the availability of these advancements, it is now possible to create spark-free, dust-free actuation mechanisms for applications where it is crucial that no spark is generated (i.e. space shuttle fuel valve). In this research, a Lulzbot TAZ 6 desktop material extrusion system was utilized to print parts out of Plasticized Copolymer Thermoplastic Elastomer (PCTPE) with manually embedded Flexinol shape memory alloy (SMA) wire to create 3D printed movable parts that could be used for actuation in larger systems. The part’s motion relies upon the activation of the SMA and on the recovery of the initial shape by the polymer’s stiffness, when the wire ceases to be activated. This activation was achieved by joule heating, where the current input was calculated using a heat transfer mathematical model. The design was driven by dimensions obtained through bending stress calculations that modeled the force exerted by the activated wire on the polymer surrounding the wire. The design based on the calculations was fabricated and reproduced a motion of ~1.8 mm. It is concluded that actuators are possible to be created using AM with the embedding of SMA wires; however, the design for fabrication can be very limited.
Mechanical engineering|Electrical engineering|Materials science|Plastics|Nanotechnology|Polymer chemistry
Fernandez, Alfonso, "Development of Actuators Using Material Extrusion Additive Manufacturing with Embedded Shape Memory Alloy Wire" (2019). ETD Collection for University of Texas, El Paso. AAI13886847.