Marshall Aerospace and Defence: Taking 3D printing to new heights

Posted on 24 Jun 2019 by Jonny Williamson

Cambridge-based Marshall Aerospace and Defence Group is flying high with flight-ready 3D printed production parts. Jonny Williamson visited the company to discuss how it achieved its success, and find out what the future holds.

The total global 3D printing market was worth around $8bn in 2011. By 2022, it’s expected to almost treble in size to $21bn. One business contributing to that growth – and benefiting from the technology’s recent advancements – is Marshall Aerospace and Defence Group (ADG).

Marshall is one of the world’s largest privately-owned independent aerospace and defence companies, serving international customers in military and commercial markets across air, land and sea domains.

Established more than 100 years ago, the company has built a reputation for delivering leading applied engineering services based on agility, innovation and a collaborative approach. Its independence is viewed internally as being paramount to its continued success.

Marshall Aerospace and Defence Group - Image 1 CROP

Having the freedom to move quickly and decisively has seen Marshall at the forefront of ground-breaking and challenging projects, from deploying sensitive medical equipment, to fleet availability and integrating some of the most complex modifications ever seen in the defence industry.

The company’s 900-acre headquarters at Cambridge Airport – which it also owns and operates – covers all aspects of design, manufacture, maintenance, modification, conversation and service support for aircraft.

Like every manufacturer, Marshall has experienced customers demanding increased responsiveness, reduced production time and cost, and almost constant innovation. The businesses decided to investigate the possibilities of integrating industrial-grade additive manufacturing solutions within its design and production process.

Today, the company utilises the technology for prototyping, advanced tooling and final part production – which includes producing flight capable parts.

Complex parts, not complex machines

Land Systems, part of Marshall Aerospace and Defence Group, is using additive manufacturing solutions to seamlessly and cost-effectively provide proof of concept to customers.

“In Land Systems, we need to create prototypes of extremely complex parts, without having to resort to a complex machine,” explains Stuart Dean, design manager at Marshall Land Systems.”

“By having [an in-house 3D printing capability] we have an easy-to-use system that provides dependable results throughout the prototyping process. Previously, we had to outsource our prototyping requirements, which caused a bottleneck in productivity.”

“We can now produce a prototype within a day, whereas, in the past, we could have to wait up to six weeks.”

Additive manufacturing

According to Chris Botting, materials, processes and additive manufacturing engineer at Marshall, the ability to create accurate, repeatable and reliable 3D printed parts using aerospace-approved materials are key factors in achieving the performance requirements necessary for use within aircraft.

A challenge Marshall faces with modifying existing platforms is that accurate, up-to-date data isn’t always to hand.
A challenge Marshall faces with modifying existing platforms is that accurate, up-to-date data isn’t always to hand.

“When manufacturing on complex engineering programmes, we need a method that can create an accurate, complex, functional and lightweight duct efficiently with minimal tooling costs – this is where 3D printing fits perfectly,” he says.

A challenge Marshall faces with modifying existing platforms is that accurate, up-to-date data isn’t always to hand. Only 2D plans are available for many legacy platforms, and the generic models don’t always match the reality as customers often modify their aircraft.

Having to work around existing structures also places certain size, power, weight and cooling constraints on design.

Ensuring accurate form, fit and function of parts required multiple prototypes to be iterated, tested and tweaked – costing time, money and effort.

This is where the marriage of 3D printing with 3D laser scanning technology (which Marshall engineers carry out onsite) and digital modelling has proved to be a winning combination. Complex prototypes can now be produced and de-risked within a day (compared to previous turnaround times of up to six weeks).

But it’s not just rapid prototyping where the benefits are being seen, other parts of the business are using the technology for limited production runs.

Customised tool kit

Traditionally, tools would be manufactured in aluminium, which was often expensive and time-consuming. This left the team with very little room for flexibility or error in the event of sudden design changes.

“We now regularly produce customised, low-volume tools within 24 hours of an engineer’s request, and at a fraction of the cost of an aluminium tool,” says Botting. “Using high-performance, engineering-grade thermoplastics, we can produce tools tailored to specific jobs with repeatable, predictable quality.

3D Printing - 3D printed forming tool in Stratasys Nylon 12.
3D printed forming tool in Stratasys Nylon 12.

“In the case of tooling to install a bracket, we would often produce these tools in Nylon 12. This material is lightweight, reducing the burden on the operator and, crucially, can be produced in a very short timescale reducing the time the aircraft is out of service.”

Other Marshall tooling applications that use additive manufacturing include drill jigs, masking templates, bonded fixtures, composite mould tooling and even sacrificial tooling (unfathomable with the cost associated with traditional manufacturing techniques).

According to Botting, the ability to create accurate, repeatable and reliable parts, as well as the use of advanced materials, holds the key to achieving the certification required to enjoy the benefits of 3D printing.

Approval rating

Marshall currently has 14 parts approved for flight with the largest of its four 3D printing machines (a Fortus 450mc FDM Printer supplied by Stratasys) certified to repeatedly produce these parts in a specific aerospace-grade material. These parts are classed as class 3, i.e. tertiary or non-load bearing such as ducting and interior cabin structures.

To ensure that the ducting work produced will be approved by the European Union Aviation Safety Agency (EASA) for flight, Marshall is using the Fortus 450mc FDM Printer and ULTEM 9085 resin – a tough, yet lightweight 3D printing material with high thermal and chemical resistance.

“This has been crucial to overcoming the stringent requirements of our industry, as we can now 3D print parts with the desired flame, smoke and toxicity properties for use on aircraft interiors,” says Botting.

3D Printing - Final, flight-approved, ducting for air conditioners, 3D printed in ULTEM 9085 resin on Stratasys’s Fortus 450mc
Final, flight-approved, ducting for air conditioners, 3D printed in ULTEM 9085 resin on Stratasys’s Fortus 450mc

Other certified parts include a cockpit safety knife holder, a chaff and flare selector switch housing mounted to the pilot control column, and a custom cover to protect the coaxial ports of a laptop with plug-in diagnostics hardware.

Marshall is also utilising its 3D printer to build final parts on the ground. The team recently created a ducting adapter prototype for vital ground-running equipment – essential for providing fresh air to cool the aircraft’s avionics.

“Before committing to expensive aluminium machining, we used the Fortus 450mc to 3D print a prototype in ASA material,” says Botting. “It enabled us to create an accurate working prototype of a complex component.”

However, the protype worked so well that the team was able to demonstrate it had the potential to be 3D printed in Nylon 12 material as opposed to the more conventional aluminium. Reportedly, the 3D printed duct led to a significant cost reduction compared to machining the part out of aluminium, as well as a 63% reduction in overall weight.

The future?

Within Marshall, Botting foresees the use of Stratasys FDM additive manufacturing to increase across all elements of the business and to drive new applications, with the potential introduction of metallics mooted.

3D Printing - A Fortus 450mc FDM Printer manufactured and supplied by Stratasys.
A Fortus 450mc FDM Printer manufactured and supplied by Stratasys.

“FDM technology has altered the way we work, and the aerospace-grade 3D printers and materials enable us to meet our increasingly aggressive deadlines and complex manufacturing requirements,” Botting said.

“Today, we have successfully identified areas of the aircraft in which we can optimise the use of certified 3D printed parts to great benefit. In the future, there is no doubt that 3D printing will continue to have a significant impact in the way we design and manufacture in our business.”

For Andy Middleton, Stratasys executive vice president, material science will be the key growth driver for the 3D printing industry. More importantly, however, he sees a very real need for the global community of technology leaders, printer manufacturers, material scientists, distributors and related stakeholders to come together and collaboratively set recognised standards.

Achieving flight-worthy regulatory certification for parts is a lengthy and onerous process – arguably necessarily so. However, Marshall had to navigate much of that red tape alone, albeit with support from Stratasys.

“If we are to accelerate the adoption of 3D printing, venders and suppliers can’t leave it to individual businesses to figure this stuff out and shoulder the burden by themselves,” says Middleton. 

How are aerospace businesses embracing 3D printing?

The below list is by no means exhaustive; in fact, it barely scratches the surface. But what it reflects is how the sector – from global OEMs to disruptive start-ups – is already benefiting. Adoption of the technology and what it offers is only likely to grow over the years as further advances are made, certifications are established, and precedents set.

Rolls-Royce has produced the largest ever civil aeroengine component using 3D printing. Working with Coventry’s Manufacturing Technology Centre, the company printed the front bearing for a Trent XWB-97 engine, made from titanium and measuring 1.5m across.

The bearing contains 48 individual aerofoil-shaped vane components which were additively manufactured.

A collaboration between Materialise and Airbus which began with the aerospace giant 3D-printing ‘hidden’ plastic parts for the A350XWB has progressed to producing parts that will be visible to passengers in the cabins of Airbus’s commercial aircraft, such as panels located alongside overhead storage components.

Airbus has also collaborated with Stratasys to produce 3D printed polymer non-structural parts and other parts used for system installation for its A350XWB.

GE Aviation has FAA clearance to use a 3D-printed part – compressor inlet temperature sensor – in a commercial jet engine. GE contracted with Boeing to use the part in more than 400 GE90-94B engines in its 777 aircraft.

Additionally, GE Aviation will use 19 3D-printed fuel nozzles to help power the next generation of wide-body aircraft like the 777X, and researchers at Oak Ridge National Laboratory have fabricated a trim-and-drill tool that will help Boeing manufacture aircraft wings for its 777X aircraft.

Legacy aircraft used by the US Air Force require parts that may be out of production due to manufacturing obsolesces, costs to create, low quantity requirements, poor documentation or other availability-related challenges.

An initiative overseen by America Makes – the national additive manufacturing innovation institute – and led by the University of Dayton Research Institute – has brought together technology and manufacturing specialists, including 3D Systems, Lockheed Martin, Orbital ATK and Northrop Grumman to explore how the US Air Force can use 3D printing to overcome such issues.

Oerlikon and UK-based disruptive rocket propulsion start-up, LENA Space, are co-developing optimised additive manufactured components for propulsion systems. The collaboration includes the qualification of a payload fairing bracket installed on small launch vehicles used to place payloads in low earth orbit.