Frequently asked questions
How powerful are Miga Shape Memory Alloy Actuators?
As you can see in the movie (here), a DM01 actuator weighing only 0.7 ounces can easily heft a 7 pound bowling ball; almost 160 times it's own weight. That's the equivalent of a 200 pound man lifting 32-thousand pounds: the weight of a loaded cement truck!
What provides the motion/force of Shape Memory Actuators?
Miga motors harness the power of Nickel-Titanium 'muscle wires' that contract when they are heated with electrical current. Because these special wires remember their original shape, they are called Memory Metal or Shape Memory Alloy wire
Why should I use a Miga memory metal actuator instead of a solenoid?
Solenoids (and, in fact, every other motor in the world) are much heavier than Miga memory metal actuators for comparable force output. Solenoids are also ON/OFF devices, and do not have speed, force, or position control; all of which are possible with Miga motors. Miga shape memory actuators also produce a constant force throughout the entire stroke, while the output force of a solenoid drops dramatically after the first 10% of motion.
Why should I use a Miga memory metal actuator instead of an electric motor?
Motors are, by design, rotary devices. Translating rotation into linear motion is less efficient than the direct linear motion provided by Miga 'muscle wire' actuators, and also requires gearboxes and linkages. Miga shape memory actuators are linear by design and most appropriate for linear motion.
What applications are appropriate for Miga muscle wire actuators?
Any application where compact, silent, non-magnetic, electrically driven, high force, linear motion is desired. These applications would include robotics, scientific and laboratory instruments, home and office automation, hobby, automotive, medical, and aerospace.
How long do Miga memory metal actuators take to actuate?
The 'S125' actuates in less than 0.12-seconds when powered with 5 volts. With higher voltages they can operate much more quickly: faster than 50ms at 24 volts. By controlling the power applied to a Miga shape memory actuator, the actuation can be carefully tuned to many specific applications.
How do I operate Miga's shape memory actuators?
Connect a battery or power supply capable of supplying several amps (see data sheets) between the actuator ground (black wire) and power line (red wire). It is safest to start with low voltages, and increase the voltage to a level appropriate for the desired speed. Voltages above 12V are capable of damaging (overheating) the wire, so limit switches or other power cutoff circuitry such as Miga's MADv5 must be used to protect the actuator. Miga is also working on a miniature, micro-controller-based, integrated controller modules that will safely power our actuators. We will add the controller to our site as soon as it becomes commercially available.
Can I use AC power?
Yes. Either AC or DC power can be used.
Can shape memory actuators be used in high vacuum or high cleanliness applications?
Yes. Miga memory metal actuators are constructed entirely out of high strength engineering thermoplastics and stainless steel. Unlike motors or solenoids, no lubricants or greases are required. (Special orders are required to ensure that only vacuum approved materials are used.)
How long will Miga shape memory actuators last?
All of our shape memory devices are designed for more than 100,000 cycles. When used properly, they will provide millions of cycles of operation.
Do muscle wire devices make noise when actuated, the way motors or solenoids do?
No. A phase transition in the shape memory metal powers the actuators, and occurs without any sound. Compared to "whirring" motors or "clunking" solenoids, Miga shape memory actuators are totally silent: perfect for applications where quiet operation is desired.
What temperature range can the memory metal devices withstand?
The shape memory phase transition begins at roughly 72˚C (162˚F), then needs to cool below roughly 65˚C (150˚F) to return fully to the un-powered position. They can operate below -20˚C (-4˚F), and even at liquid nitrogen temperatures.