Engineering in Reverse, Part 2: (Material) Testing 1, 2, 3

By Jonathan McFadden
Editor’s note: This is the second installment of “Engineering in Reverse,” a three-part series in which we will explore the facets of reverse engineering, from process to product.
Nearly two years ago, Kevin was on the prowl for an expert.
An engineer with a long list of projects, he searched for someone to help his company, a 20-year-old aviation maintenance firm, test the alloys, steel and brass needed to reverse engineer aircraft stilts, shear pins and reservoir cylinders.
“You don’t always have the expertise to be able to do it,” Kevin said from his office in Louisiana. “There was a need for some repairs on parts. We needed to get involved with (a company) to help us get the certification done” so the Federal Aviation Administration would approve the repairs.
That’s when he found AeroTech Engineering Consultants. With more than a decade of experience in aerospace and aviation, AeroTech helped Kevin and his company reverse engineer a slew of parts and tools that would help garner FAA approval. And to ensure those components could be replicated properly, AeroTech subjected them to material testing, a process to determine which physical and mechanical properties are suitable in the manufacturing of parts or components, such as for aircraft or packaging.
“Without doing that step of the process, you wouldn’t be able to do the full proof or repair,” Kevin said. “It’s critical.”
Why? When engineers design aircraft parts, they have to consider a number of factors to determine whether said parts are durable. Along with making concessions for normal operating conditions that could affect the part, such as stress and vibration, engineers must also weigh how parts will function under abnormal circumstances, such as in hard landings or air turbulence. The materials’ response to environment is also critical in aircraft and different depending on the part location.
During the reverse engineering process, it’s critical these characteristics are duplicated for both replicating the part and maintaining aviation safety. Some features are simple to test (steel or aluminum) while others are more elusive and require several tests to ensure a successful replication (compression set or TGA for non-metallic materials).
AeroTech has extensive experience testing materials and understands the pitfalls of the process. When we reverse engineer a material, we couple it with our careful testing process to completely replicate the OEM parts. That way, we deliver to our clients a reverse-engineered design that’s safe, secure and functional. Here’s how.

How does it work?
Before engineers can start testing materials, they have to start reverse engineering products. Much of that involves using an array of cameras, lights and scanners to reproduce an original part’s geometry so it can be duplicated.
Once they’ve produced a computer-aided design model to duplicate a part, engineers can identify the component’s trouble spots and discern how certain materials will react to pressure in abnormal situations. Engineers can then reverse engineer the most critical characteristics of certain materials and apply them to a new part in production.
There are some caveats.
For some materials, the replication process is seamless. Duplicating aluminum brackets or plastic trim pieces is fairly simple since those materials are easily replicated.
Other materials, on the other hand, are trickier and the process becomes more complex if the material is a result of a manufacturing process and not the individual elements, such as composites, plastics, rubbers, or 17-4 PH steel.

Why is testing necessary?
Materials only get you so far. Since every material comes with trade offs, a part often exhibits modifiers to compensate for the material weakness. Case in point: coating aluminum with an oxide layer to improve corrosion resistance, or shot peening the surface of a steel part to gain fatigue life. Heat treatments and even some surface processes can influence a part’s response to loading during operation. The trick is knowing what to look for and how to test the presence of these processes.
AeroTech has more than 20 years of manufacturing experience in aerospace so we know what to look for.
Little to nothing in engineering (aviation, especially) amounts to guesswork. Much of it requires due diligence, empirical data and lots of patience.
We can’t just look at an object and decide what costs the least to manufacture. Careful analysis is paramount. And for parts suppliers that need the FAA’s parts manufacturing approval certification (the FAA has released a series of guidelines on how certain materials should behave in abnormal aviation situations), trusting your parts to a partner with the skill, talent and resources to test materials before you unveil a finished reverse engineered part is crucial.

Trust us.
AeroTech has an extensive record of obtaining PMA’s for customers needing assistance to identify and specify which materials were right for their projects.
Just ask Kevin. Ever since AeroTech analyzed materials for his company’s parts, he’s maintained an ongoing relationship with us.
“They come with the knowledge; they’ve done it before,” he said of AeroTech. “We’d be reinventing the wheel if we started from scratch.”
And who has time for that? Our customers are parts suppliers with busy schedules, tons of projects and narrow production windows. We aim to provide quality service that produces timely, accurate results. We have the know-how and capability to test materials and reverse engineer parts so you can continue providing exceptional service to your clients and outclass the competition.