What Is Multisensor Metrology? A Practical Guide for Aerospace and Defence Inspection

If you work in aerospace or defence inspection, you soon run into parts that do not suit one measuring method.

A camera can measure visible edges and small details very well, but it cannot deal with every hidden face or recessed feature. A touch probe can physically measure features that optics cannot reach properly, but it may be slower than optical measurement for simple visible geometry. A laser can be useful for profiles, height changes and surface form, but it is not the right answer for every feature either.

This is the basic idea behind multisensor metrology. Instead of choosing one measurement method and trying to make it do everything, a multisensor system brings different measurement tools together on one machine. The inspection routine can then use optical, tactile or laser measurement depending on the feature being checked.

For aerospace, defence and precision manufacturing, that can be a very practical advantage. Many parts include a mix of visible features, deeper geometries, curved surfaces, tight tolerances and reporting requirements. A single component may need more than one way of being measured properly.

What is multisensor metrology?

Multisensor metrology is dimensional measurement using more than one sensor type on the same measuring system.

A typical setup may include optical measurement, tactile probing and laser measurement. These are not competing technologies. They are different tools for different features. The aim is to build a measurement routine around the part, rather than forcing the part through one inspection method.

For example, an aerospace component may have a hole pattern that can be measured optically, a recessed face that is better suited to a touch probe, and a curved surface that needs laser measurement. On a multisensor system, those measurements can be brought into one inspection workflow.

That is the useful part. The system is not limited to one way of seeing or touching the component.

Why aerospace and defence parts often need more than one method

Aerospace and defence components are often awkward by nature. They may be small, complex, expensive, tightly toleranced or difficult to handle. Some are machined from demanding materials. Some are part of assemblies where a small dimensional issue can create problems later. Some need clear inspection records for customer, supplier or internal quality requirements.

Typical examples include machined aerospace components, engine-related parts, structural mounts, hydraulic components, actuator parts, connector housings, electronic assemblies, tooling, fixtures and first article inspection parts.

The issue is not that these parts are impossible to measure. The issue is that different features may call for different measurement methods. Treating the whole part as an “optical job” or a “probe job” can sometimes make the inspection slower, less practical or more dependent on operator judgement than it needs to be.

Optical measurement

Optical measurement uses a camera, optics and controlled lighting to measure visible features. It is commonly used for edges, holes, slots, profiles, contours and small details. Because it is non-contact, it can be useful for delicate components or features where touching the surface is not ideal.

In practice, good optical measurement depends on more than magnification. Lighting, focus, fixturing and edge detection all affect the result. A feature may be easy to see, but that does not automatically mean it is easy to measure repeatably.

This is where proper application work is important. The question is not simply whether the system can view the feature. The question is whether it can measure it consistently as part of a routine that works in the real inspection environment.

Tactile probing

Tactile probing is still important because some features need physical contact. A bore, plane, recessed face, hidden feature or deeper 3D geometry may not be suitable for optical measurement alone.

On a multisensor system, the touch probe can be used only where it adds value. The optical system can handle the visible features quickly, while the probe deals with the features where contact measurement is the better option.

That is often a more sensible approach than trying to use one method for the whole part. It keeps each measurement method doing the work it is good at.

Laser measurement

Laser measurement can help when the inspection task involves surface shape, profile or height variation. It may be useful for curved surfaces, steps, freeform shapes or areas where a surface needs to be measured rather than visually judged.

In aerospace and defence applications, this can be relevant for shaped machined parts, moulded or composite-related features, and components where surface form is part of the inspection requirement.

As with any sensor, the important point is application fit. Laser measurement is useful when the feature needs that type of data. It should not be added simply because it sounds more advanced.

Why keeping the inspection on one system can help

When a component has to move between separate measuring machines, each move adds handling, setup time and another alignment step. For a basic part, that may be acceptable. For a high-value aerospace or defence component, it can become a source of time loss and variation.

A multisensor system can reduce the need to move the part between different inspection methods. Optical, tactile and laser measurements can be included in the same routine where the application supports it. This can make the process easier to control and easier to repeat.

It does not mean every part should be measured on one machine. Some applications still need a different approach. But when the component has a mix of features that suit different sensors, a multisensor system can make the inspection process more straightforward.

Where OGP fits

OGP is known for optical and multisensor dimensional measurement systems used in industrial quality control. OGP SmartScope systems can combine optical, tactile and laser measurement technologies, depending on the system configuration and application.

For aerospace, defence and precision manufacturing, this means a single system can be configured to inspect different types of features on the same part. Visible geometry can be measured optically, contact measurement can be used where needed, and laser measurement can be applied to suitable profiles or surface forms.

OGP systems are also supported by metrology software such as ZONE3, which is used to create, run and report measurement routines. This is important because inspection is not only about getting a measurement once. The routine has to be clear, repeatable and useful for the people who will run it again.

What to check before choosing a multisensor system

Before choosing a metrology system, it is worth looking carefully at the component and the inspection requirement. The right setup depends on the part, the tolerances, the features, the material, the surface finish, the reporting needs and the environment where the system will be used.

Useful questions include:

• Which features are visible and which are hidden or recessed?

• Is contact measurement acceptable on the component?

• Are there curved surfaces, profiles or height changes to measure?

• Does the inspection require 2D measurement, 3D measurement or both?

• Is the surface reflective, dark, polished or difficult to light?

• Will the system be used for development, production, MRO, first article inspection or supplier quality?

• What reports are needed?

• How many parts need to be inspected?

• Who will operate the system?

The answers help narrow the discussion. A compact optical system may be enough for one application. Another part may need optical and tactile measurement. A different component may justify laser measurement as well.

This is why the best conversation usually starts with the part and the drawing, not the machine model.

OGP support in the Middle East

AIET Group is OGP’s partner and distributor across the Middle East. We support aerospace, defence and precision manufacturing customers with OGP metrology systems, application review, demonstrations, system selection and local technical support.

For many inspection projects, the first step is not choosing a machine. It is understanding the measurement problem clearly enough to choose the right approach.

That normally means looking at the component, the drawing, the tolerances, the current inspection method and the features that are causing difficulty. From there, it becomes much easier to decide whether optical measurement, tactile probing, laser measurement or a multisensor configuration is the right route.

Speak to AIET Group about OGP multisensor metrology

If you are reviewing measurement options for aerospace, defence or precision manufacturing, AIET Group can help assess the application before you choose a system.

That can include reviewing the component, drawing, tolerances, feature access, reporting needs and current inspection process.

Contact AIET Group to discuss OGP multisensor metrology applications across the UAE and wider Middle East.

Frequently asked questions

What is multisensor metrology?

Multisensor metrology means using more than one measurement method on the same system. A machine may use optical measurement, tactile probing and laser measurement in one inspection routine, depending on the features being measured.

Why use more than one sensor?

Different features need different measurement methods. Optical measurement may be best for visible edges and holes. A touch probe may be better for recessed or deeper geometry. Laser measurement may be useful for profiles, curves and surface form.

Is multisensor metrology only used in aerospace and defence?

No. It is also used in medical devices, electronics, precision engineering, automotive, energy and general manufacturing. Aerospace and defence are good examples because the parts are often complex, costly and tightly controlled.

Is optical measurement the same as vision inspection?

Not exactly. Both use cameras, but they are usually used for different purposes. Optical metrology is focused on dimensional measurement. Machine vision inspection is often used for presence checks, orientation, defects, codes or assembly conditions. There can be overlap, but they are not the same thing.

When would a touch probe be needed?

A touch probe is useful when the feature needs physical contact to measure it properly. This may include bores, planes, recessed faces, hidden features or certain 3D geometries that are not suitable for optical measurement alone.

When would laser measurement be used?

Laser measurement can be useful for profiles, curved surfaces, height changes and surface form. It is normally considered when the shape of the surface needs to be measured rather than simply viewed.

Does every application need optical, tactile and laser measurement?

No. Some applications only need optical measurement. Some need optical and tactile measurement. Others may need laser measurement as well. The correct configuration depends on the part and the inspection requirement.

What information should we prepare before speaking to AIET?

The most useful starting points are the part drawing, CAD model if available, sample part, tolerance requirements, photographs and details of the current inspection method. It also helps to know what is causing the issue now, such as access, speed, repeatability, reporting or operator variation.

Does AIET supply OGP systems in the Middle East?

Yes. AIET Group is OGP’s exclusive partner and distributor across the Middle East. AIET supports customers with application review, demonstrations, system selection and local technical support for OGP metrology systems.