Hi,
We are currently working on process for shot peening 300M steel parts. I find it really hard to inspect coverage on this material, the dimples being quite small. I tried using blue dye as a tracer but it doesn't seem to do a great job when shot peening a part for the first time. I've seen areas where tracer was gone but no significative dimple was present, especially on really smooth, machined or grinded surfaces. My questions are the following:

1 - What equipments are currently used for coverage inspection in shot peening industry? We use 10X and 20X magnifiers but I'd like to know if there's some kind of microscopes that could do a better job in performing surfaces inspection. I've also been looking at those products :

http://www.keyence.ca/products/vision/microscope/vhx500/vhx500.php

Those are digital microscopes, is anybody aware of the use of such technology for coverage/surface inspection?

2 - When using a scrap part to set the proper exposire time/feed for 100% coverage, is it OK to perform peening many times on the same part to optimise cycle time? Will a previously peened part take less time than a "new" part to show 100% coverage using blue dye?

Thanks!