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Posted By: Jack Champaigne Shot size substitution - 12/02/05 10:37 AM
I received the following message:
Dear Sir,

I am asked to approve the use of a different size bead for applying the
specified shotpeen intensity on a machined aluminium connection angle,
because the bead size specified on drawing is not available.

The main function of the angle is to transfer shear from a panel to shear in
a panel mounted 90 degrees to the first panel ("T"-junction).


The bead size specified on drawing is 0.093" with intensity 0.010-.014 A2

The available bead sizes we have are 0.066" or 0.125".

I intend to allow the use of the larger bead size 0.125", using the same
intensityas specifed on drawing, but I have no real justification for it
(other than smoother surface?).

Do you agree, or can you advise me which bead size would be preffered to use
and why?

MB
Posted By: Dr Peener Re: Shot size substitution - 12/02/05 10:29 PM
Dear MB,
First we should recognize two aspects of your request: 1) the authority to change the process and 2) the technical equivalence of changing the process.

If you are performing the peening under contract (purchase order etc) that requires the 0.093" shot size then you would want to get permission to change. If you are the part or process owner than you should proceed with your process variation review.

Technically, achieving the same intensity (probably lower air pressure or slower wheel speed, will provide the same depth of compression. However, you must be sure that the shot diameter is smaller than the fillet radius. Generally the diameter must be equal or less than half of the fillet radius.
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