Extreme Precision: How Devices Move Just Thousands of an Inch

[taupune]

Hi guys, I have been wondering for a while so to how it is possible to make devices that move only thousands of an inch.

Does anyone know? I have asked my prof at school but his specialty wasnt that. One examle that comes to mind is the mill and leath machines.

check this out:
http://science.nasa.gov/headlines/y2004/21jul_llr.htm
People on Earth shoot a laser and wait for it to come back in order to find the distance and the precision has to be freaking accurate.

i have been wondering since i watched a documentary 3 years ago. I need some answers, please. thanks.

 

[russ_watters]

My telescope does that. All you need is gears.

 

[Ranger Mike]

instruments in quality control in industry can position to .00008" accuracy and repeat to .0001"

 

[taupune]

is it done by precision machining? Can it be done by electromagnetic forces, like maglev, or by pumps? Controlling the amount of liquid in it?

How much does that Microscope of yours Watters cost? Do you sell the gears separately?

 

[Mech_Engineer]

I have designed several optical alignment systems that are sensitive on the micron scale (1e-6 m), and it is not unheard of to make ones sensitive in the nanometer scale. Kinematic (exact-constraint) design concepts become very important, as well as thermal expansion, friction, material stiffness and hardness, and a host of other small factors.

For example, these actuators have sub-micron scale sensitivity: http://search.newport.com/i/1/nav/1/q2/Manual%2520Positioning/q3/Manual%2520Actuators/q4/DM%2520Series%2520Differential%2520Micrometers/x2/section/x3/chapter/x4/family

 

[vargasjc]

Just as well, in the silicon industry masks are used to expose the silicon in the lithography process of manufacturing the computer chips. As the transistor gates have been getting smaller and smaller the process of creating these masks has been getting more and more complex, and so also the process of how to use these masks efficiently. Since nowadays we are talking about gates as small as 32 nanometers that is how precise these masks have to be. The gaps are so small that the light wavelength has to be chosen so very carefully, among with a grillion other factors and work arounds that are part of the industry.

How do you make devices that work on such small scales? Materials.

 

[Mech_Engineer]

Suffice to say it isn't easy to make a lithography laser that can fabricate transistors on the 32nm scale. You're right that the light wavelength has to be chosen carefully (probably far-UV). In addition, friction has to be minimized, athermallization of the design must be done, exact constraint of the laser's moving parts, etc. etc. When you take into account lever arms, it is possible to steer the beam on very small scales.

You might try finding something about design considerations in a CPU lithography laser, but it's possible most are considered trade secrets for manufacturing.

 

[vargasjc]

You might try finding something about design considerations in a CPU lithography laser, but it's possible most are considered trade secrets for manufacturing.

Indeed. The problem is that at this scale everything costs so much money that it's unfair otherwise.

Maybe it's a good idea to see if there's a high precision manufacturer in your area. I remember visiting one somewhat near where I live when I was in the university. They charged large sums of money for small parts (at very competitive pricing regardless), and obviously all tools were CNC tools and the techniques for achieving tolerance specifications were eye opening. The beauty of it is that they may be more lax in terms of showing how they do things so precise.

 

[optoguy79]

I would add that your work environment is going to play a big part. If you are in a garage with no temperature control you can expect thermal expansion to cause variation in your equipment.

 

[Emreth]

Micrometers are used to measure down to 0.0001 in, so in theory they can be used to move linearly that much as well. You can buy one as low as $37, hook up a motor at the end with limiters(something that will keep it from rotating further), then you can move anything that much back and forth. Or use a stepper motor for larger displacements.

http://en.wikipedia.org/wiki/Micrometer
http://www.google.com/products/catalog?hl=en&q=micrometer&cid=15972622902749532321&sa=title#p