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#1314 - 01/18/18 04:15 PM 2007 SCS-10 Roto-Peen 2 Parameter
zellmld Offline
Member

Registered: 01/18/18
Posts: 4
When entering intensity data values in the Subject Saturation Curve Solver spreadsheet, all uncorrected arc heights are automatically corrected (.77 factor applied). Boeing spec BAC5730-2 Section 8.5b.(4) states "The arc height of a strip peened in a magnetic holder must be multiplied by 0.77 to obtain a corrected Almen intensity for all arc heights greater than 0.005A". In order to make the Peen Solver work correctly, intensities < .005 have to be artificially increased sufficiently such that application of the .77 factor corrects these increased values back to the original uncorrected value.

Am I using the program incorrectly or not utilizing a feature designed to deal with this?
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L. Zellman

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#1316 - 01/18/18 06:12 PM Re: 2007 SCS-10 Roto-Peen 2 Parameter [Re: zellmld]
Dave Barkley Offline


Registered: 04/13/11
Posts: 43
Loc: USA
I really appreciate you registering for an account and posting your question.

You may have uncovered a mistake in the new Boeing spec. I have not been provided a copy of the new spec, so I cannot confirm what you have quoted.

Your curve solver (and everyone elses) use the conversion method from the previous version 5730-2 Rev C. It required the same x0.77 adjustment, but from zero. The change you mention would drastically change the values between the old and new spec. It would also cause a greater divide between the Boeing and AMS/3M spec. (which also adjusts only arc heights greater than 0.005", but at a factor of x0.6).

I have reached out to our associates at Boeing to ask about this and am waiting on a reply. In the meantime I think you could revert back to the previous spec and multiply by 0.77 for all arc heights like the curve solver does.
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Dave Barkley
EI Shot Peening Training

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#1317 - 01/19/18 07:50 AM Re: 2007 SCS-10 Roto-Peen 2 Parameter [Re: zellmld]
zellmld Offline
Member

Registered: 01/18/18
Posts: 4
Thanks for the quick response, Mr. Barkley. I appreciate your advice.

I suspect that the 5730-2 Rev D change stating the .005A limit may be associated with the Boeing internally developed Shot Peen Curve Solver.
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L. Zellman

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#1318 - 01/19/18 09:41 AM Re: 2007 SCS-10 Roto-Peen 2 Parameter [Re: zellmld]
Dave Barkley Offline


Registered: 04/13/11
Posts: 43
Loc: USA
Another company heavily involved in rotary-flap peening has conducted trials with the magnetic holder and found the AMS/3M adjustment to be more accurate than the previous Boeing rule. As stated, the new Boeing rule will increase the gap.

We discuss the differences during our RFP training course. With the AMS/3M having a larger conversion ratio while beginning at 0.005" the two (old) standards would yield the same result when adjusting a measurement near 0.0125", and of course 0.0".

I have speculated that Boeing created their original rule as an easier method of conversion and selected their multiplier of 0.77 was to have their result equal 3M's targeted intensity value, 10A. Both the Boeing and 3M conversion yield almost identical results; Boeing's 0.013x0.77=0.0100, 3M's ((0.013-0.005)x0.6)+0.005)=0.0098.

Applying the Boeing's RevD method to the same measured arc height is a big change. ((0.013-.005)x0.77)+0.005)=0.0112. The difference between the two standards lessen as you near 0.005, but increase with larger arc height values.

I do hope this is a simple mistake. If it stands, all existing rotary flap curve solvers will need to be changed. There's also the question if the old Boeing conversion is meant to still be used on older parts/airframes. If so, the curve solver programs will have to offer both methods and hope the technician knows which one to use.

I'm still waiting for word back from the guys that have the answers.
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Dave Barkley
EI Shot Peening Training

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#1326 - 01/31/18 10:38 AM Re: 2007 SCS-10 Roto-Peen 2 Parameter [Re: zellmld]
Dave Barkley Offline


Registered: 04/13/11
Posts: 43
Loc: USA
Zellmld,

I have had a response from someone at Boeing and they do not have an issue with the revised arc height conversion rule and implied that the results will not differ from the adjustments of the past.

I gave this more thought. I still don't have the new spec, but if the only change is the addition of "for all arc heights greater than 0.005", then there isn't much change from the old spec. Magnetic arc heights greater than 0.0050" are treated the same. The oddity the added text creates is values between 0.0050 and 0.0065 resulting in an adjusted value below 0.005" Example:

(MAH = Magnetic Arc Height & AAH = Adjusted Arc Height)

MAH = AAH
0.0040 = 0.0040 <- new method, new result
0.0045 = 0.0045 <- new method, new result
0.0050 = 0.0050 <- new method, new result
0.0051 = 0.0039 <- new method, same result
0.0055 = 0.0042 <- new method, same result
0.0060 = 0.0046 <- new method, same result
0.0065 = 0.0050 <- new method, same result
0.0070 = 0.0054 <- new method, same result

The method for using an existing curve solver is the avoidance/rejection of any non-adjusted arc heights 0.0050" or less.

I will post again if I receive any new information.
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Dave Barkley
EI Shot Peening Training

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#1327 - 02/07/18 12:18 PM Re: 2007 SCS-10 Roto-Peen 2 Parameter [Re: Dave Barkley]
zellmld Offline
Member

Registered: 01/18/18
Posts: 4
Thank you, Dave. So I presume that the intensity fudging method I describe in my first post is the way to go, yes?
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L. Zellman

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#1332 - 02/16/18 01:19 PM Re: 2007 SCS-10 Roto-Peen 2 Parameter [Re: zellmld]
Dave Barkley Offline


Registered: 04/13/11
Posts: 43
Loc: USA
Sorry that a on-site training has delayed my response. I think there's a grace period for implementation in most specs., so you may want to ride it out if you have one.

I plan to wait until summer before having the code re-written for the curve solvers EI offers. Until then, the x0.77 conversion of Dr Kirk's Excel based solver and the Peensolver webapp will not work correctly for entered values between 0.0001" - 0.0050"
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Dave Barkley
EI Shot Peening Training

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