Surface roughness guage

[kabluzy]

Does anyone know the best portable equipment to use for measuring surface roughness of sculptured surfaces? I need to measure the roughness of complex NURBS surfaces in mold cavities. The size of the cavity is about 2.5" x 2.5".

Thanks

 

[unclesyd]

If you are in cavity the only way is replicate the surface and the measure or compare with set of roughness/finish standards.

 

[aamoroso]

Accurately measuring it will be difficult, I would think you are probably going to be stuck with a visual comparison to roughness gauges. There are some nice small portable surface gauges out there but cost is pretty high and they are still limited due to location problems, such as in a cavity.

 

[PatRiordan]

A couple of questions. Is this a curved or straight surface. A curved surface will require a skidless profilemeter while a flat section will work with a skidded. The best skidded portable that I have currently seen is a Mahr Federal and depending on the complexity of what measurements you want it can cost from $1600 to $5000 for the unit. Simple Ra can be measured with a Pocket Surf but if you want other parameters or a Firestone curve and hard copy you will need their Perthometer. A curved section will need a skidless and that is not portable and the cost goes up to about $25,000. You would need to make a mold using faximilie and then take it to the stationary machine. A more complex process. Final thing is what is your limit of roughness specified. If it is really fine you may not even get there with this equipment.