3D-Printed Jigs, Fixtures and Assembly Tools for Aerospace: When MJF, SLS or FFF Makes Sense

How aerospace manufacturers can use additive manufacturing to reduce tooling lead times, improve ergonomics, and select the right process for durable production aids.

In aerospace manufacturing, the parts that never leave the factory can be just as important as the parts that eventually fly.

Assembly fixtures, drill guides, alignment tools, inspection fixtures, masking tools and custom workholding all help technicians build complex assemblies accurately and consistently.

Traditionally, many of these tools have been machined from aluminum, steel or engineering plastics.

But not every tool needs to be machined.

For the right application, 3D-printed jigs and fixtures can reduce tooling lead times, eliminate unnecessary machining, lower tool weight and make design changes much easier to implement.

The challenge for mechanical and manufacturing engineers is deciding not only whether to use additive manufacturing, but also which 3D printing technology makes the most sense for the application.

For polymer tooling, three processes worth considering are Multi Jet Fusion (MJF), Selective Laser Sintering (SLS) and industrial Fused Filament Fabrication (FFF/FDM).

Here's how to choose...

Why Aerospace Manufacturers Are Using 3D Printing for Jigs and Fixtures

Aerospace manufacturing involves relatively low production volumes, complex geometries and frequent requirements for application-specific tooling.

That combination can make traditional tooling expensive, particularly when a fixture is needed for only one operation, one assembly configuration or a limited production run.

Additive manufacturing changes the economics because parts are built directly from digital CAD data without requiring dedicated tooling to manufacture the tool itself.

That makes 3D printing particularly useful for:

• Assembly fixtures
• Alignment fixtures
• Drill and trim guides
• Inspection and checking fixtures
• Custom workholding
• Component nests and cradles
• Masking fixtures
• Ergonomic hand tools
• Composite layup aids
• Production line aids
• Robotic end-of-arm tooling
• Replacement tooling and legacy fixtures

Instead of machining a relatively simple fixture from a large block of material, engineers can design the tool around exactly what the operator and process require.

The Bigger Advantage: Design the Tool Around the Job

The biggest benefit of additive manufacturing isn't simply making an existing fixture faster.

It's the ability to redesign the fixture specifically for additive manufacturing.

A machined tool is constrained by cutter access, setups and the geometry of the starting stock. A 3D-printed fixture gives engineers much greater freedom to put material only where it is needed.

That can make it possible to incorporate:

Part-conforming geometry.
Surfaces can follow complex aerospace components more closely, providing better support and positioning.

Integrated features.
Handles, labels, cable routing, vacuum passages, locating features or hardware mounts can potentially be incorporated into the design rather than added later.

Weight reduction.
Material can be removed from areas that don't carry meaningful loads, making large tools easier for technicians to handle.

Fewer components.
Assemblies made from multiple machined pieces may sometimes be consolidated into a single printed tool.

Rapid revisions.
If the aircraft component or manufacturing process changes, the CAD model can be updated and a new fixture produced without modifying hard tooling.

For aerospace programs where designs, configurations and assembly processes evolve, that flexibility can be extremely valuable.

MJF vs. SLS vs. FFF: Which Process Should You Use?

There isn't one universal “best” additive process for aerospace tooling.

The right choice depends on the fixture's size, loading, temperature exposure, dimensional requirements, geometry, quantity and material requirements.

MJF: A Strong Choice for Durable, Detailed Production Fixtures

Multi Jet Fusion (MJF) is an industrial powder-bed process that works particularly well for strong, detailed polymer components and batches of repeatable parts.

Because the parts are supported by the surrounding powder during the build, engineers have considerable geometric freedom without designing traditional support structures into the part.

For aerospace manufacturing, MJF can be a strong fit for:

• Assembly fixtures
• Component nests
• Inspection fixtures
• Small-to-medium workholding devices
• Complex locating tools
• Production aids
• Repeat fixture sets used across multiple workstations

MJF is especially attractive when repeatability, complex geometry and production quantities matter.

For example, if an aerospace manufacturer needs the same assembly aid at 20 workstations, the ability to efficiently build multiple fixtures within the same production workflow can be valuable.

When to Consider MJF 

Look closely at MJF when you need:

• Multiple identical tools or fixtures
• Complex geometry
• Good mechanical durability
• Detailed features
• Relatively consistent properties throughout the part
• Nylon-based engineering materials
• Production-quality appearance and finishing options

Material selection can also change fixture performance considerably. Standard PA 12 is useful across many functional applications, while more rigid material options may be appropriate when dimensional stability and stiffness are higher priorities.

SLS: Durable Nylon Tooling with Excellent Geometric Freedom

Selective Laser Sintering (SLS) is another powder-bed additive manufacturing technology commonly used for strong functional polymer parts.

Like MJF, SLS surrounds the component with powder during printing, allowing engineers to produce complicated geometries without conventional support structures.

That makes SLS useful for tooling with:

• Internal passages
• Complex contours
• Difficult-to-machine geometry
• Integrated features
• Lightweight structures
• Functional nylon requirements

SLS can be particularly valuable when material requirements or application geometry point toward the SLS material set.

For aerospace tooling, potential applications include:

• Drill and alignment guides
• Assembly aids
• Duct and tube positioning fixtures
• Protective fixtures
• Complex checking tools
• Custom handling tools
• Low-volume production aids

When to Consider SLS

SLS deserves consideration when your project requires:

• Tough functional nylon parts
• Complex, support-free geometry
• Good durability
• Specialized nylon material characteristics
• Low-volume or one-off tooling
• Intricate internal or external features

For engineers comparing MJF and SLS, the decision often comes down to the combination of material, geometry, dimensional requirements, surface expectations, quantity and economics rather than one process simply being superior to the other.

Industrial FFF: Ideal for Larger Tools and Specialized Materials

Fused Filament Fabrication (FFF), also commonly referred to as FDM, approaches tooling differently.

Rather than fusing a bed of powder, FFF deposits thermoplastic material layer by layer. Industrial systems can process a wide range of engineering-grade thermoplastics, including fiber-reinforced materials.

That opens up opportunities for larger fixtures, specialized materials and applications where the size-to-cost relationship favors extrusion-based printing.

Potential aerospace applications include:

• Large assembly fixtures
• Trim and drill templates
• Manufacturing aids
• Composite tooling aids
• Large component nests
• Protective covers
• Ergonomic tools
• Robotic tooling
• Low-volume replacement fixtures

Carbon-fiber-reinforced materials can be particularly interesting where greater stiffness and dimensional stability are required.

When to Consider FFF

Industrial FFF often deserves consideration when you need:

• A relatively large tool
• Specialized engineering thermoplastics
• Carbon-fiber-reinforced materials
• High stiffness-to-weight
• A one-off or low-volume fixture
• Geometry that works well with the directional nature of the process
• Fast production without machining a large billet

The important word here is industrial.

A production aerospace fixture should not be evaluated the same way as a basic desktop 3D print. Machine capability, material control, orientation, process settings, finishing and dimensional inspection all affect the final tool.

Quick Process Selection Guide 

This is only a starting point.

Part size, geometry, tolerances, loads, environmental exposure and required quantity can change the recommendation quickly.

Don't Choose the Process Before Defining the Fixture Requirements

One of the easiest mistakes to make is starting with:

“We want this 3D printed.”

A better starting point is:

“Here is what the tool needs to do.”

Before selecting MJF, SLS, FFF, or additive manufacturing at all...

Define the actual operating requirements:

1. What Loads Will the Fixture See?

    Consider clamping force, technician handling, vibration, impact and repeated loading.

    A lightweight assembly nest experiences very different conditions from a drill fixture subjected to repeated tool forces.

2. What Temperatures Will It Experience?

    A fixture used at room temperature may have very different material requirements from tooling located near heated equipment, cure cycles or other elevated-temperature processes.

    Material selection should reflect the actual service environment.

3. How Accurate Does It Need to Be?

    Not every fixture needs machining-level tolerances across every surface.

    Identify which dimensions actually control the manufacturing process.

    Critical locating features may require tighter dimensional control or secondary operations, while non-critical sections of the same fixture may not.

    This is an important opportunity to avoid overengineering, and overpaying for, the tool.

4. What Will Contact the Aerospace Component?

    The interface between the fixture and finished component matters.

    Engineers should consider:

• Surface hardness
• Abrasion
• Contamination requirements
• Contact pressure
• Cosmetic surfaces
• Chemical exposure

    Soft interfaces, replaceable pads or secondary components can sometimes be incorporated where appropriate.

5. How Often Will the Tool Be Used?

    A fixture needed for five assemblies and a fixture expected to survive thousands of cycles should not automatically use the same design or material.

    Expected service life should be part of the manufacturing decision from the beginning.

6. Could Hardware Be Integrated?

    3D-printed fixtures don't have to remain entirely plastic.

    Designs can incorporate conventional hardware such as:

• Threaded inserts
• Bushings
• Pins
• Bearings
• Fasteners
• Clamps
• Wear surfaces

    This hybrid approach can combine the geometry and speed of additive manufacturing with metal components where localized strength, wear resistance or precision is required.

A Printed Fixture Doesn't Need to Replace Metal Everywhere

A common misconception is that additive manufacturing competes directly with machined aluminum for every tooling application.

It doesn't—and it shouldn't.

Some tools absolutely should be metal.

The better engineering question is:

Where does the application actually require metal?

A fixture may need hardened drill bushings at two locations, for example, but that doesn't necessarily mean the entire 10-pound structure needs to be machined from aluminum.

A printed polymer body combined with appropriately selected metal hardware can sometimes deliver the needed functionality while reducing weight, manufacturing steps and lead time.

The goal isn't to 3D print everything.

The goal is to use the right manufacturing method in the right places.

Where 3D-Printed Aerospace Tooling Creates the Most Value

Additive manufacturing tends to become particularly compelling when several of these conditions occur together:

• The fixture geometry is complex.
• Only a few fixtures are required.
• The design may change.
• Lead time is important.
• The tool is unnecessarily heavy when machined conventionally.
• Multiple components could be consolidated.
• The geometry would require extensive machining.
• Operators would benefit from a more ergonomic design.
• Different configurations require customized tooling.
• Replacement tooling needs to be produced from digital inventory.

In these situations, evaluating additive manufacturing early can eliminate unnecessary cost and complexity from the tooling program.

From CAD File to Production Tool

Successful additive tooling requires more than uploading a CAD file and pressing “print.”

Process selection, material selection, orientation, wall construction, tolerance strategy, hardware integration and finishing all influence performance.

That is why SICAM approaches additive manufacturing as a manufacturing problem first and a printing problem second.

With MJF, SLS, industrial FFF and additional manufacturing technologies available in-house, our team can evaluate the actual application rather than forcing every fixture into a single process.

For mechanical and manufacturing engineers, that means you don't have to decide whether your fixture should be MJF, SLS or FFF before contacting us.

Send us the requirements.

We'll help determine the manufacturing approach.

Need an Aerospace Jig, Fixture or Manufacturing Tool?

If you're currently machining an expensive fixture, waiting weeks for tooling, redesigning an existing production aid, or developing a new aerospace assembly process, it may be worth evaluating additive manufacturing.

Send SICAM your CAD file and tell us what the tool needs to do.

Our team can review the geometry, application, quantity, material requirements and operating conditions to help determine whether MJF, SLS, FFF—or another manufacturing process—is the right solution.

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