Micron accuracy linear motion over short distance?

[jscpm]

I have an application where I need linear motion over a short distance with micron level accuracy. So, ideally the stage would move in increments of about 0.00005" and have a range of at least around 0.002" so about 40 steps altogether, although 100 steps would be nicer. It can be manual, does not need to be automated.

The problem with most high precision stages is that they use micrometers for movement, so the motion is continuous (and often there is no back pressure, so there are backlash issues). I was kind of hoping for a stage that has a stepped motion with some kind of detente, so I can click in the distance I want in increments of 0.00005". Is there anything like that?

 

[Robert R]

A flexure mounted stage driven by a differential screw adjusted sliding wedge would be a inexpensive option. The differential screw can have a disk attached with holes spaced as needed for the required steps similar to a dividing head. There are more expensive solutions involving stacked piezo electric actuators or voice coil actuators.

The Thor labs catalog describes a number of options.

Actuators, Adjusters, & Transducers - Thorlabs

Thorlabs specializes in the building blocks for laser and fiber optic systems. From optomechanical components to telecom test instrumentation, Thorlabs' extensive manufacturing capabilities allow us to ship high quality, well priced components and devices for next-day delivery. Optomechanics...

www.thorlabs.us

The Thor Labs sliding wedge micrometer (part ID HP310) was graduated in 0.5 micron increments with 300 microns of travel. I cannot find the part in their current online catalog. You can accomplish the same function driving a small slide stage mounted at a 1 degree angle (for example) with respect to the main flexure mounted stage. The small stage becomes the moving wedge.

 

[Scottl]

I have an application where I need linear motion over a short distance with micron level accuracy. So, ideally the stage would move in increments of about 0.00005" and have a range of at least around 0.002" so about 40 steps altogether, although 100 steps would be nicer. It can be manual, does not need to be automated.

The problem with most high precision stages is that they use micrometers for movement, so the motion is continuous (and often there is no back pressure, so there are backlash issues). I was kind of hoping for a stage that has a stepped motion with some kind of detente, so I can click in the distance I want in increments of 0.00005". Is there anything like that?

Yes, you want to find the people who do the servo drives used by industries such as disk drive manufacturers who use it to control head position while low level formatting new disks. That is the reason why users nowadays NEVER perform low level formatting anymore. The mechanism in the drive itself is accurate enough to "stay within the lines" but not determine them.

As I recall, they interpolate sine waves in quadrature from the position sensors to reach that level of accuracy and the servo control is also quite sophisticated.

 

[EPAIII]

Can't you supply the back pressure with a spring. One with 0.002" of range is not a big challenge to find.

Yes, most do use a micrometer screw to provide the motion. You can purchase a commercial stage with a micrometer, usually a standard mechanical micrometer. It should be easy to replace that one with a digital one that reads down to 0.00005". Or perhaps the manufacturer of the stage will do that as a special.

I would call some people. A good start may be Edmond Optics. They have a number of stages available.

Manual Translation Stages and Slides | Edmund Optics

Manual Translation Stages and Slides ideal for providing varying degrees of movement to mounted optical components for optical applications are available at Edmund Optics.

www.edmundoptics.com

Such a mechanical stage could be modified with a stepper motor and perhaps a timing belt drive. Steppers will provide at least 200 steps per revolution and you want 1/500 of one revolution on a 40 TPI micrometer screw so a 2.5::1 step down should do the trick. A place like Edmond may be able to supply it as a complete, working device.

Using a stepper would allow a computer, tablet, or PIC style device (Arduino, Basic Stamp, PICAxe etc,) to control it.

 

[Erich]

This is the actuator you want. https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=9776. You can mount these on most micrometer stages in place of the manual micrometer.
If you really need good motion control, get a gothic arch bearing slide. (not crossed roller or the ball on rod designs)

 

[Beags]

This is probably overkill but might lead you down the right rabbit hole. https://www.physikinstrumente.store/us/m-105-microtranslation-stage/

 

[jtaylor]

Piezo stages will do what you need. There are many varieties:

 

[crrmeyer]

Piezo stage with position feedback is what you need.