Contacts observation 1

[mereaux]

Hi everybody,

I am working on contact problem between rubbers, I have difficulties to observe the contact (only some microns width and over the length more than 30cm). Does anybody know methods to measure contact of difficult accessible part? I mean like a moulding method??

thanks for your advice!!

 

[btrueblood]

How about pressure-sensitive film/paper?

http://www.sensorprod.com

 

[mereaux]

It seems to be a real interesting tool! Do you know if it is easy to read and if we can have a very fine pressure distribution over the length (in the order of few microns)?

 

[CoryPad]

mereaux,

You can obtain hardware and software that enable film scanning and high resolution analysis. Contact Sensor Products at the Internet site shown above.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[btrueblood]

Meraux,

According to some literature from the above supplier, the resolution of the film is 5-15 microns. I think the number increases with the pressure sensitivity of the film.

What kind of a contact problem between two rubber parts do you have? I'm having a little trouble believing you need to know that accurately, could you describe the problem a little better?

 

[mereaux]

I need a fine accurancy because I need to know if Particles whose size is about some microns (5-10microns)can go between these 2 Rubbers. For this problem I need to have a look at the wear/Roughness of the Rubbers. The film that you speak about, can perhaps permit me to understand if one rubber can "penetrate" in the other, and if there is space between them.

 

[IRstuff]

Why can't you collect the air in a filter and count the particles?

A 5 micron particle is unlikely to leave a 5 micron footprint on any material

TTFN

 

[mereaux]

I try to be more precise:

My system acts like a sweeper, the rubbers are always in contact to remove particles. And the contact pressure is a crucial parameter for this. But the rubbers present a wear/roughness during aging, and the system can not be so efficient. I cannot use a filter in the setup of my sytem and I cannot count the particles.

 

[mereaux]

Hi everybody

I tried those films, but it is not precize enough in spite of the fact I hav emore information about the pressure between my rubbers.

any other idea?

Mereaux

 

[IRstuff]

When the state of the art fails to provide a solution, perhaps it's time to re-think the problem.

Why is it mandatory to have the spatial resolution you've asked for? You say you're looking for wear, so why not use a profilometer to measure the wear directly? You can get profilometers with better than 0.1 angstrom resolution.

TTFN

 

[btrueblood]

mereaux,

I'm sorry the film did not work, but that's why they pay us engineers -- to try and figure things out. A guess at what you are doing would make me think you could measure gaps optically - i.e. shine a light on one side, and look for light leaking through to the other side through small gaps? But you may have trouble with "edge effects" (diffraction) if the gaps are very small.

I'm still pretty confused about what you are trying to do, so I don't know what else to suggest.

Good luck!