Manufacturing of artificial muscle actuators
Methods and a device for the continuous manufacturing of artificial muscle actuator device fibers are disclosed. The method includes: threading an untwisted fiber along the axis of a tube and inside the tube that includes a heating means to raise the localized temperature of a cross-section of the tube to a predetermined temperature; providing a tension on the untwisted fiber; and twisting the untwisted fiber while the fiber is within the tube.
1. A method of manufacturing an artificial muscle actuator fiber, the method comprising:
providing a tube having one or more continuous heating sections along a length of the tube; and
in a continuous process,
threading an untwisted fiber along the axis of the tube and inside the tube from a first end of the tube towards and passing an opposite second end of the tube;
providing a tension on the untwisted fiber;
twisting the untwisted fiber while the fiber is within the tube by applying a rotational force to the untwisted fiber such that the fiber is continuously twisted at a twisting point that is intermediate the first end of the tube and the opposite second end of the tube,
advancing twists, formed by twisting the previously untwisted fiber, towards the opposite second end of the tube,
wherein the tube is configured to prevent snarling during the twisting of the untwisted fiber,
providing an inner diameter of the tube to be 10% to 20% larger than a diameter of the untwisted fiber, and
wherein the tube is further provided as a heater to raise the localized temperature of a cross-section of the tube to a predetermined temperature.
2. The method of claim 1 , wherein the predetermined temperature is selected to be between the glass transition temperature of the fiber and the melting temperature of the fiber.
3. The method of claim 1 , wherein the untwisted fiber comprises a polymer fiber selected from the group consisting of Nylon 6, Nylon 6,6, polyethylene, polyvinylidene fluoride, Nylon 6,10, Nylon 6,12, liquid crystalline polymers, polyarylate, and combinations thereof.
4. The method of claim 1 , wherein the untwisted fiber comprises carbon nanotubes (CNT).
5. The method of claim 1 , further comprising: applying a coating to the twisted or untwisted fiber.
6. The method of claim 1 , further comprising: applying a coating to the fiber while the fiber is inside the tube.
7. The method of claim 1 , further comprising: removing moisture from the untwisted fiber prior to threading the untwisted fiber along the axis of the tube.
8. The method of claim 1 , further comprising: supplying an inert gas inside the tube.
9. The method of claim 1 , further comprising: supplying a lubricant inside the tube during the twisting.
10. The method of claim 1 , further comprising: threading the twisted fiber along an axis of a second tube, wherein the second tube comprises a second heater to raise the temperature of a cross-sectional area of the second tube to a second predetermined temperature.
11. The method of claim 10 , wherein the second predetermined temperature is greater than the predetermined temperature.
12. The method of claim 1 , wherein the tube has a plurality of heating sections; and, in a direction from the first end of the tube towards the opposite second end of the tube, a diameter of a heating section of the tube is larger than a diameter of any preceding section of the tube.
13. The method of claim 12 , wherein the twisting of the untwisted fiber forms a coiled fiber inside the heating section of the tube that has a larger diameter than a preceding section of the tube.