methods for quantifying surface texture of honeycomb-cored sandwich panels?

[reidiculous]

Does anyone have a good method for quantifying the surface texture on a composite-skinned sandwich panel featuring honeycomb core? Looking for a proven method if possible, not brainstorming. my customer wants parts with less surface texture, and all our metrics are currently subjective, which is extremely frustrating

sandwich panel skins are generally fiberglass or carbon fiber prepreg, in a variety of fabric styles, and can be either a flat panel, or crush-core molded to a 3-d geometry. common causes for texture in the part surface include a. tow pockets of skin material, b. telegraphing of the core, c. wrinkles / pits

anything helps!

 

[waterlogged4]

They use a quantitative method here that might help you out.

http://www.oxeon.se/uploads///Media... Composite surface smoothness improvement.pdf

 

[reidiculous]

Thanks kindly for the response per the OptiTopo system from Innventia. anyone on here have past experience using an optical inspection system like this, specifically on composite materials?

I would prefer a contact-based system, but off-the-shelf profilometers won't work due to A) sharp point of stylus (could catch tow pockets in composite skin, scratch part) and B) short stroke length (honeycomb core cells generally 1/4" across). any other suggestions?

 

[AeoN909]

If you want a solid number you can use a diffracto. (is a bit old but it works)

Problem with surface quality is that it is always subjective. The computer can say it is good but when you take a look it's bad.

To get rid of the subjectiveness, we have a couple of tl lights fixed on the wall with a table in front of it. We put the sample on the table and we have a look with minimal 3 guys and try to give a score on different parameters. You can use the reflection of the light to see the waveness and other surface defects.

Probably not the answer you wanted but i hope it helps.