Vision measuring systems for next-gen materials

Aerospace parts don’t just need to be right. They need to be perfect. As aircraft and spacecraft designs push the limits with lighter composites, thinner walls, and intricate geometries, any margin for error doesn’t exist. And it’s a challenge to measure these delicate, high-precision components quickly while avoiding distorting the part or leaving a blemish or other type of marring on the part’s finish.

Using a vision measuring system in aerospace manufacturing offers many advantages as these systems deliver a rare combination of speed and accuracy while measuring critical parts without touching them.

The shift to advanced materials

Aerospace manufacturers today work with a diverse range of materials, from traditional metals such as aluminum and titanium to advanced composites and micro-structured components. These materials offer strength and efficiency but also pose new challenges for inspection. Thin-walled parts, micro-EDM features, and delicate surfaces can’t tolerate deformation or contamination which makes traditional contact-based measurement methods less viable.

Enter vision measuring systems: a category of high-precision metrology tools relying on optical technology to inspect parts without physical contact. With the ability to measure large and small features at high speeds, these systems are fast becoming essential tools in the aerospace industry.

Why non-contact measurement matters

In aerospace manufacturing, dimensional tolerances often live in the single-micron realm, so a hole drifting even a micron, or a bracket whose geometry is nudged out of spec, can upset fuel-flow dynamics, shift load paths, or introduce vibrations propagating through the entire airframe. A classic example is the micro-perforated fuel nozzles used in aircraft gas turbines. These precision-engineered holes, typically ranging from 5μm to 100μm in diameter, are crucial for atomizing jet fuel into a fine mist within the combustion chamber. The taper, roundness, and cylindricity of these holes must be meticulously maintained to ensure a uniform spray pattern, directly impacting combustion efficiency, fuel consumption, and emissions.

Studies demonstrate even minor geometric deviations in these small EDM-drilled injector holes can disrupt fuel flow and spray consistency, leading to measurable increases in unburned hydrocarbons and NOx emissions. This underscores the critical importance of precision in manufacturing these components, as any deviation can compromise the performance and environmental compliance of the engine.

Coordinate measuring machines (CMMs) with touch probes, or any other system using tactile probes for measurement, have difficulty in this application. If the ruby tip is almost as big as the tiny feature being checked, the probe is a tiny amount off-axis, or the software isn’t compensating for the tip’s radius, these uncertainties can pile up quickly, increasing the measurement error with a much higher likelihood the part will be discarded. Worst case scenario is a part passing inspection but not performing as designed or specified, which could lead to catastrophic results.

Non-contact vision systems eliminate the contact variable. Higher-end precision vision measurement platforms use optics and sub-pixel image processing to capture edge data down to 0.25µm without ever touching the workpiece. Since the measurement force with a vision system is literally photons, there’s zero chance of plastic deformation, probe deflection, or the can’t-quite-fit-the-styli issues plaguing CMM work in tight internal geometries.

In a business where a few microns can decide whether a part flies or fails, non-contact vision metrology offers a no-touch, no-transfer, sub-micron path to confidence allowing aerospace manufacturers to measure the most fragile EDM-cut injector or composite bracket in full fidelity without risking the very defects they’re trying to avoid.

Furthermore, aluminum or other materials commonly used on aircraft can suffer damage such as indentations or dents, scratches, and scuff marks from the probe tip being much harder than the material and too much force being used. Vision measurement systems bypass this entirely.

Speed without sacrificing accuracy

Time is money: Every minute a finished part sits in a quality-control queue, capital is tied up, schedules slip, and downstream stations wait.

Inspecting parts quickly while maintaining ultra-tight tolerances can significantly improve throughput. Vision measuring systems can acquire multiple dimensional measurements with micron-level tolerances to dramatically reduce cycle times and speed up measurement throughput.

Modern technologies including high-speed cameras, strobing light systems, and software-enhanced image processing improve the speed of measurement by continually moving while measuring, unlike traditional vision measurement requiring stopping and waiting for the camera to settle for each measurement. Today’s vision systems can capture multiple features and dimensions in rapid succession without having to pause the camera to acquire measurement readings.

This reduces measurable cycle times up to 45% in some applications without sacrificing accuracy – beneficial when inspecting components with multiple small features or holes, such as in turbine engine parts or micro-mechanical assemblies. The simultaneous, multi-dimensional capturing means you’re not trading quality for speed: you get both.

The importance of magnification and pixel resolution

Accurate vision measurement depends on pixel size and magnification. Higher magnification reduces pixel size, increasing the system’s ability to detect fine edges and minute features. This improved fidelity is critical when tolerances are measured in microns or sub-microns.

Zoom lenses and interchangeable objective lenses allow operators to adjust magnification based on the feature size and required tolerance. A large gear might be best measured with a lower magnification to capture the entire feature in one field of view. Conversely, a micro-machined component would benefit from higher magnification for smaller pixel size and more accurate edge detection.

Multi-sensor versatility

Modern vision systems are more than just optical devices. Many now integrate additional sensors such as touch probes and lasers to expand their measurement capabilities and add versatility. While non-contact measurement is ideal for top-down surface measurements, optional probes are a great supplement to measuring side features or internal depths not visible to the camera.

Switching between sensors within a single measurement routine without moving the part ensures better inspection speed while preserving alignment. This seamless transition between vision and contact methods minimizes uncertainty introduced by repositioning and streamlines the complex measurement workflow. To put it simply, the less an operator touches or moves the workpiece being measured, the more trusted the measurement will be.

Managing measurement uncertainty

For high-stakes aerospace components, quantifying measurement uncertainty is as important as capturing the measurement itself. The industry standard guideline is the measurement system should be 10x more accurate than the tolerance zone of the part.

For example, if a component’s tolerance is ±10μm, the measurement system must be accurate to ±1μm or better. Vision systems equipped with high-resolution optics and advanced algorithms can achieve this, even down to sub-micron levels in specialized configurations.

This level of precision ensures all components, even those not easily accessible once assembled, meet their exact specifications to enhance overall reliability while reducing maintenance costs.

Easing the skills gap with smarter software

One challenge across manufacturing, particularly in aerospace, is finding skilled operators and programmers. As parts become more intricate with tighter tolerances and increasingly complex geometries, programming accurate and reliable inspection routines becomes a highly specialized task. It’s no longer about taking a few point-to-point measurements; now, inspection often involves 3D contours, internal features, or non-standard geometries requiring custom strategies. This complexity demands a deep understanding of metrology principles and the specific software or equipment being used, making onboarding new personnel time-consuming, costly, and increasingly more difficult.

To help overcome this skills gap, metrology software providers are redesigning their user interfaces to be more visual, guided, and user-friendly. Many modern systems now include intuitive drag-and-drop interfaces, CAD model integration, and wizard-style programming tools walking users through each step of creating a measurement routine. Some platforms even offer feature recognition, where the software automatically identifies holes, slots, or surfaces on a CAD file and recommends or auto-generates a suitable measurement plan.

These advancements significantly reduce the learning curve, allowing newer technicians to get up to speed more quickly while enabling experienced users to work more efficiently. As a result, manufacturers can deploy measurement systems faster, improve consistency, and scale inspection capacity even with a limited pool of expert talent.

Artificial intelligence (AI) is beginning to reshape the landscape of dimensional inspection as well, and its influence will likely grow in the coming years. Today, some advanced vision systems leverage AI for defect detection by training models using large sets of images showing examples of acceptable and unacceptable parts. These models learn to distinguish subtle differences that might be missed by traditional rule-based inspection methods. For instance, a system can be trained to identify hairline cracks, tool marks, or surface deformations falling outside acceptable limits, even when they’re inconsistent or irregular in appearance.

In the near future, artificial intelligence (AI) could go well beyond defect detection. One promising development is AI-assisted measurement programming. Currently, creating measurement routines, especially ones for complex parts, requires a skilled operator to manually define features, set tolerances, and program each measurement point. This process is time-consuming and can vary based on the programmer’s experience.

AI, however, could change that. By analyzing the CAD model or a high-resolution scan of the part, AI software could automatically recognize part features such as holes, edges, threads, and contours and intelligently apply the appropriate measurement strategies. This would significantly reduce the setup and programming time required to inspect new parts, allowing for faster deployment and easier scalability in production environments.

Emerging technologies

Sensor technology continues to evolve. Near-infrared imaging, for example, is already being used in certain semiconductor applications to see through opaque layers. While its relevance in aerospace remains limited, similar technologies could someday help inspect composite or layered materials otherwise difficult to measure optically.

The road ahead

As aerospace manufacturing pushes the boundaries of design, material science, and production, the metrology systems supporting it must evolve as well. Vision measuring systems offer a unique blend of speed and accuracy without touching the part, making them ideal for the demands of measuring next-generation aerospace components with high accuracy and improved efficiency.

By combining optical and tactile technologies, reducing cycle times, and enhancing accuracy through intelligent magnification, vision systems are poised to remain at the forefront of precision inspection to ensure every part, no matter how small, will perform as designed with every takeoff, landing, or launch.

Mitutoyo America Corp.
https://www.mitutoyo.com

About the author: Mark Sawko is vision product manager for Mitutoyo America Corp.