Surface finishes from glass bead abrasive blasting

[Tunalover]

Does anyone have a chart, graph, or something that provides surface finishes (in rms microinches) vs pressure, time, and bead diameter for abrasive glass bead blasters (e.g. for a TRINITON 36/BP2)? Does the model and manufacturer of the machine matter?

I'm a design engineer and would prefer to call out a surface finish over calling out a process on our drawings (we're trying to stick to defining the end-item and trying to avoid specific processes).

One of our suppliers said his TRINITON 36/BP2 provides 8-16rms to AL6061-T6 using .005 beads at 25psi but he didn't say how long it takes. Would there be much difference between values for 6061-T6 and, say, aircraft grade titanium?

Lastly, our QA department wants to know if there is there an easy way to measure rms surface finish. Any recommendation?

Thanks in advance!


Tunalover

 

[tripleZ]

Profilometers will give you surface finish values. Go to

http://www.mahr.com

and you should be able to find something to fit your application. Coming from a manufacturing perspective, I tend to prefer surface finish values rather than specifying a process. Doing that limits your manufacturing options, unless you're planning on using this supplier exclusively.