Home Forums General Discussion Ask Dr. Peener coverage

Dear Mr.Champaigne,
I have already posted my question on the Specicfications Forum but no one is responding to my question, maybe I confused everyone.
I am not very experienced so I will try to reword my question.
Our machine is a Wheelabrator computerized shot peen machine. We are currently running our conveyer speed at 2" per minute which is how we established our curves. As a test we recently increased the speed to 3" per minute and we are getting excellent coverage and our production would increase signifigently. My question is will this hold up in an audit if we use 2" a minute to prove saturation and intensity using almen strips but run our parts at 3" a minute proving 100% coverage on our parts by visually inspecting them.
My coworker is referencing PSD 6-88 8.4.2 and says that will suffice.
Thank you so much for any information you could give me.
SUE

Will it suffice? Possibly. It depends upon how you conducted your saturation curve.
1. If your saturation curve was done properly then you should be ok. This is because the trials for saturation curve are used ONLY for intensity determination, NOT time needed for proper part coverage. If your parts appear to be properly covered with a line speed of 3" per minute then you're in good shape.
2. If your saturation curve was not done properly then you might have some issues. The saturation curve requires incremental exposures to the shot stream, primarily by changing the exposure time which can be done by changing the feedrate. So, if your satruation curve is ploted against (inverse) feed rate you are probably ok. On the other hand, you could have left the line speed fixed at 2"/minute and then passed the Almen strips through the machine once, twice, three and then four times to give you the required four data points for the saturation curve. This method would also be ok since it is used to only reveal the peening intensity, not the time needed to cover your particular parts.
I hope this helps.

Indeed it does help!
Our saturation cuves were done using your recomended Almen Saturation Curve Solver Program,and we plotted it by using the (inverse) feed rate hat you mentioned above.
You are very much appreciated.
Sue