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How to specify a laser marking process that doesn't fit AS478.

KirbyWan

Aerospace
Joined
Apr 18, 2008
Messages
590
Location
US
Howdy all,

I'm trying to figure out how to callout this marking process, since nothing in AS478 seems to cover it. We want to mark a part using a laser to cure a coating onto stainless steel sheet. The process is to apply dry moly lube or a specialty product like CerMark and then cure the material using a ~60W CO2 laser similar to what Omtech makes. After cure the part is cleaned and the un-cured coating wipes away leaving a clear dark mark. For my limited testing the marking seems stable and solvent/skydrol resistant.

Thanks,

-Kirby
 
My experience...

AS478 Rev S... LASER marking ref 'is as good as it gets'.

MIL-STD-130N w/C1 Seems to have better definition for LASER marking.
 
Also run some samples. I don't recall laser marking coated parts.
Bare steel or Chem filmed aluminum.
Coated has been tag or rubber stamped.
Or engraved .but I think it will work.
 
A CO2 laser can't significantly etch stainless steel which is what I think the AS478 process is indicating which gives minimum/maximum limits for material removal. The process I'm using is more like fusing the coating onto the metal and everything else gets wiped away.

This is what it looks like:

S20250728_0009.jpg
 
A CO2 laser can't significantly etch stainless steel which is what I think the AS478 process is indicating which gives minimum/maximum limits for material removal. The process I'm using is more like fusing the coating onto the metal and everything else gets wiped away.

This is what it looks like:

View attachment 15920
It's good, very proffesional and visible
 
This is typically handled by an in-house specification for the process. Take the AS478 / MIL_STD-130 as a basis for selecting durability requirements and include any requirements for material cleaning and handling of the pre-cured material with regards to shelf life.

I would contact CerMark for their inputs on process requirements. They should have a motive to get included in AS478 and MIL-STD-130 as a recognized process.

Until then you will need to convince the end user that this is sufficiently permanent for the duty the item is subject to.
 
Following the lead on the last page of this doc from CerMark


Gets you to something like "apply laser bonded marking per NASA-HDBK-6003 para 5.1.5."

And this one gets you

NASA-STD 6002 NASA Marking Standard
- Section 5.3.1 Non-intrusive Marking Page 27

and MIL-STD 130M DOD Marking Standard, Table II

Once you know the term "laser bonding "you can also find a bunch of other suppliers, any of which might have further suggestions.
 
Can't you define your own process ? why must it be a "commercial" spec ?
 
It depends on the contract/PO of the customer.
Commercial , or military contract
 
We could define our own process. But we're working on a PMA part and if we use a commercial/government spec, that's less of a hurdle to justify for a DER to buy off. So a commercial or government spec is always preferred, and we'll leave creating our own process to when we're doing something truly novel.

-Kirby
 
It sounds to me that your process is less invasive than other options (you're not etching into the material, right?) so that sounds "good".

The OEM's part used some proprietary process for this ?

So more than just conforming to any spec, you need to rationalize your deviation from from the OEM's procedures.

I guess the key thing is how to answer when the DER asks "how do I know this will be legible after 40 (x?) years service ?"
 
My past experience with PMA., if the new process meets and or exceeds the previous process and can be justified . For example
Some old and obsolete specification and or process. Can be supersceeded. With Der concurrence.
 
I worked this issue recently with a company, whos sole purpose is use of LASER for marking, cutting, etc. Great conversations, good info. I hesitate to note the company and tech rep I spoke with... since there are several doing this work

Contact the vendor of Your marking LASER system... they should have answers

FYI ONLY...
Laser Marking vs. Engraving vs. Etching - Differences and Applications
Our guide to understanding the different laser marking technologies and when they are used.
 
Last edited:

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