Choosing the Right PAUT Equipment for Ultrasonic Inspection of Laser Welds

The aerospace industry has always flown on the cutting edge of technology. Newer, more efficient methods of assembly are continuing to be developed. But as test pilots know, innovation comes with risk, and so new safety methods must emerge alongside new technologies.

The use of laser welding in the aerospace industry, particularly for aluminum alloys including AA6013, promises a more effective means of airframe assembly (among other uses). But for both safety and regulatory reasons, airframe welds must be subjected to nondestructive testing (NDT). So, researchers tested a proven NDT method—phased array ultrasonic testing (PAUT) —to determine if it could detect internal defects in laser welds. 

The method they tested succeeded. Phased array accurately detected grouped porosity, a defect found in poor-quality welds. As a result, aerospace companies seeking to use laser welding in their assembly processes can use PAUT to ensure the integrity and safety of their products. 

Establishing NDT Procedures for Aerospace Laser Welds

As many aerospace companies already use phased array ultrasonic testing to inspect aircraft parts, this is good news. The latest assembly techniques can be integrated into production without needing to invent or invest in a new testing method. It also speaks to the ongoing relevance and efficacy of ultrasonic testing, encouraging companies to continue with PAUT as even more new techniques and materials come into use.

That’s not to say that technicians should be able to immediately be able to pick up their testing equipment and go inspect a new type of weld successfully. They may be able to choose an effective probe or even identify the increased attenuation of signal amplitude that indicated porosity to the researchers. What they won’t know, however, is if they’re seeing the whole picture.

A key element of nondestructive testing is comparing current results with those of the past. In order to confirm that test equipment is picking up all flaws, experts must analyze results from many inspections, using many methods. The findings are then codified into standards published by a number of international organizations, including ISO.

So, before implementing a new test method on a new technique, consult the relevant standards. Developing a new set of test procedures for the new technique should be done by a qualified Level III NDT technician, based on these standards. Only then can it be put into practice.

Once the standards are known and procedures established, consider whether current equipment is best suited for the job. 

Selecting Phased Array Equipment for Laser Welds

Aerospace companies rely on high-quality ultrasonic equipment for an array of inspections, so established companies beginning to use laser welds are likely to already have some form of equipment available. If the new production method replaces an old one and doesn’t increase test volume, it’s natural to question if existing equipment will suffice.

The answer depends on the capabilities, age, and condition of existing equipment. Ultrasonic equipment that doesn’t support more advanced methods like phased array should be upgraded, and software should be able to identify the specific defects found in laser welds.

All equipment ages, and must eventually be phased out. During the implementation of a new process is a good time to consider replacing aged equipment with up-to-date hardware and software. This ensures that the best equipment is available well into the lifespan of the new process.

It’s also a good time to replace any damaged or low-functioning equipment lingering in the shop. Ultrasonic test equipment can be subject to harsh environments, as well as unplanned bumps and shakes. When choosing new instrumentation, look for durable cases, no air intake, and a large operating temperature range.

PAUT equipment enables aerospace companies to inspect laser welds, helping the latest technology find safe, profitable use. Switching to laser welds for some or all assembly needs means developing NDT test procedures under the guidance of an expert. This provides a good reason to inventory and update ultrasonic test equipment to ensure inspection efficacy.

Zetec has long provided top-quality NDT solutions to the aerospace industry. Our ultrasonic testing equipment has been proven effective in factories and hangars. To find the best equipment for your testing needs, contact us today!