Dear Shruti,

Some examples of MEMS microtweezers can be found at
http://www.memspi.com
There is a wide range of tip designs of different size,
shape, and stiffness. The range of force available is
10 piconewtons to 100 micronewtons depending on the tip
selected. The normal range of tip opening displacements is 0
to 100 microns (but, we have some desings that open up to 2mm).
 Low voltage operation is possible with thermally
actuated tweezers. Our tweezers are normally closed, and they open
as a linear function of power. Typically they are designed to be fully
open at 10V and 0.1A (i.e., 1 watt). This requires good thermal
conduction in the heat sinking handle (especially in vacuum, like
electron microscopes).
 Current medical applications are limited to research
since they are not FDA approved yet. For medical applications
it is important to provide good thermal and electrical isolation
of the tip from the actuator. This is achieved in our tweezers
by fired glass frit connecting beams. For an example of a research
application see:
http://www.memspi.com/quail_ch.ss3q.html
Ultimate goals for use on humans include any kind of microsurgery,
 and microbiopsy. Of course there are limitations and hazards, but
if in the worst case a tweezer breaks in the patient, silicon is
biocompatible, and micron size pieces that might be lost in the patient
will usually not be dangerous.
Microtweezers can also be used in the microassembly of other micro
surgical devices, and micro medical mems devices that cannot be
built by the integrated planar processing that is popular in MEMS today.
 Automated robotic microassembly will be needed to build many 3
dimensional mems devices in the future.

Best regards,

Chris Keller
ckeller@memspi.com

----- Original Message -----
From: "Shruti Madhukar" 
To: 
Sent: Saturday, February 21, 2004 12:18 PM
Subject: [mems-talk] MEMS microtweezers


> Hello,
> I am a student of electrical engineering and I need to do a report on
> MEMS micro tweezers.
> Some questions that need to be addressed are
>
> * What is the range of forces (to the nearest order of magnitude)
> that can be applied with these tweezers?
> * Where might these be useful in the medical industry?
> * Limitations and possible hazards in using this type of tweezers
> in a medical application.
> Some factors to be considered are : precision, force, voltage
> size,safety
>
>
> Someone please help me out here and tell me where to search for info. My
> search has been quite useless till now.
>
> Thanks
>
> Shruti



--
Chris Keller
MEMS Precision Instruments
http://www.memspi.com