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Conditions for approval required by: Philip Edwards
Certification of Aerospace Products to international quality Standards
Certification of Aerospace Products to international quality Standards
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In « Particular remark » section, it is written: “Please note this is a renewal and is to confirm that nothing has changed since the initial qualification. The initial qualification allowed, some deviations to specification i.e Material and Chromium Plating.”
It is clear for raw material thanks to “ME1613052_v2.0_signed” document.
However, could you please give more details for chromium plating? (Only AMS2460 called out in plating CoC, but no reference to EN2132. However, flowchart does mention EN2132).
Surface appearance: marking pictures show a yellowish aspect of spherical bearings (the entire part).
Chromium plating gives this type of visual aspect. However, as per EN3048, only inner ring spherical surface shall be plated (or surface treated). Maybe this is only due to optical effect and/or heat treating operations (on that point, grinding operation is carried out after heat treatment, so thermal oxides should have been removed).
Could you please clarify?
In flowchart, ball (inner ring) made out of AISI440C is chromium plated (code P).
In flowchart, race (outer ring) made out of 17-4PH has PTFE bonded liner (code A).
In flowchart (spherical bearing 1 of 2), a passivation operation is carried out.
Could please clarify as well?
Many thanks in advance
Best regards
Julien
Hi Julien
Thanks for your comments, regarding your points raised. NMB have responded with the following
1. We can perform only AMS2460 for plate because we can’t perform EN2132.
We understand AMS2460 can use instead of EN2132 because of TR4661.
2. -> >>We perform chromium plate only to inner ring spherical surface.
This yellowish is just optical effect. It is not heat treatment scale, this has been removed on the final part.
The yellowish color is a pure lighting effect.
3. >>Yes, your understanding is everything correct.
Auditor Coment – To add to NMB’s comment, please note the 440C and 17-4PH is consistent with the designation used within the Airbus Technical Memorandum that has been attached.
4. -> Passivation – This is our customer’s requirement.
We are selling this items only for Kawasaki heavy industries and they additional require it to us.
(They request special spherical bearing it is made from EN3048.)
Therefore we perform passivation during assembly process.
We are applying passivation from first time.
Thanks
Marko
Many thanks for all these detailed answers Marko.
I am happy with all of them, except for the last one, I would have some further explanations.
Since inner ring and outer ring are assembled, how can we make sure that there is no retention of acid solution in between parts?
Hopefully, environmental test is carried out just after according to process flow chart.
Even though a peel strength test is carried out after passivation, how can we make sure that passivation bath has no influence on PTFE bonded liner?
Many thanks again
Best regards
Julien
Hi Julien
The response from Minebea is as follows
Question: Since inner ring and outer ring are assembled, how can we make sure that there is no retention of acid solution in between parts?
Hopefully, environmental test is carried out just after according to process flow chart.
Minebea Response ” We understand there is no acid retention due to we are following AMS2700 requirement. We control final rinse water accordance with AMS2700 as well to keep parts surface clean. At result, If acid solution exist on surface, it become rust but we have never seen a rust on this item. ”
AMS2700 Rev F 3.1.4 requires a thorough rinse.
EN3048 Code T requires passivation to ISO8075, AMS2700 is considered an alternative specification through TR4661 Table 9 having superseded specification QQP35.
For the following question “Even though a peel strength test is carried out after passivation, how can we make sure that passivation bath has no influence on PTFE bonded liner?”
Minebea response “We consider this passivation doesn’t affect to SPH performance.
When we had performed qualification test, all test were passed with this condition even dynamic radial load and liner compatibility with the fluids. It means liner performance doesn’t be affected by passivation. We are performing 100%-torque-check and peel strength test by each lots as well. That’s why it is nothing problem.”
As Minebea state that they have also carried out Fluid and Dynamic tests which assess the liner for wear and that was found satisfactory on product which has been passivated. Add to that, the peel test which is also also found to be successful and is a lot acceptance test demonstrates the bonding mechanism to be satisfactory.
Thanks
Marko
The conditions/questions asked Julien Gauther have been answered and are accepted. this qualification is approved.