Face wound actuators are made with a rectangular wire wound with the wide face touching the mandrel. Face wound actuators have a higher power density than helical actuators because they carry more nitinol for an actuator with the same parameters becuase the round wire only fills 2/3 of the space. With rectangular wire, there are no gaps.
General parameter relationships with force and stroke:
Increasing the width of the wire and decreasing the inside diameter increase the force produced by the actuator.
High pitch allows both compression and extension actuation. Pitch has little relation to force or stroke, it simply moves the neutral position.
Increasing the inside dameter and increasing the number of coils of wire in the actuator increases the stroke.
| Mandrel Size | 0.5mm, 0.9mm, 1.15mm, 1.6mm, 2.4mm, 3.2mm, 4.75mm, 6mm, 8mm, 9.5mm, 12.7mm, 14.2mm, 16mm, 19mm, 22.2mm, 25.4mm |
|---|---|
| Cross Section | 0.152×0.411mm (0.006 x 0.016"), 0.152×0.813mm (0.006×0.032''), 0.25×0.5mm (0.010×0.020"), 0.3x2mm (0.012×0.079"), 0.4×0.8mm (0.016×0.032"), 0.4×1.0mm (0.016×0.039"), 0.5 x 0.25mm (0.020×0.010"), 0.55×1.4mm (0.022×0.055"), 0.5×0.8mm (0.020×0.032"), 0.6×2.3mm (0.024×0.091''), 0.8×1.5mm (0.031×0.059"), 1.0×2.6mm (0.039×0.102"), 1.5x4mm (0.059×0.157") |
| Transition Temperature | 20°C (68°F), 35°C (95°F), 45°C (113°F), 80°C (176°F), SE |
| Pitch | Tight, wire size x 2, wire size x3, wire size x4 |