In recent years 3D printing of aerospace components has made great strides with ever larger parts, faster production and synergy with other materials, including composites. AEROSPACE gets an update on the latest progress from Scott Sevcik, Head of Manufacturing Solutions at international 3D printing company Stratasys.

 

Scott Sevcik, Head of Manufacturing Solutions, Stratasys. (Stratasys)

A: When 3D printing first began to be used in the aerospace industry, the main application was to print one-off parts for new prototype testing. What progress has been made since then to develop 3D printing for commercial production?

SS: The relationship between additive manufacturing and the aerospace industry is constantly evolving. 

Larger components

 

Infinite Build 3D demonstrator. (Stratasys)

A: What progress has been made on the size of parts that can be made by additive manufacturing - which was restricted by the size of the printers to make them?

SS: Over the last year we’ve launched three demonstrators. Each of these combat size, speed, strength, or cost constraints in different ways. In August 2016, we launched the Infinite-Build 3D Demonstrator. This demonstrator features a new approach to FDM (fused deposition modelling) extrusion which increases throughput and repeatability. By turning the traditional 3D printer concept on its side, the infinite-build prints on a vertical plane for practically unlimited part length. It is designed specifically to address the requirements of the aerospace industry for large lightweight thermoplastic parts with repeatable mechanical properties. We worked closely with aerospace giant Boeing to define the requirements and specifications of this demonstrator. Boeing is currently using the demonstrator to explore the production of low volume, lightweight parts. 

Continuous building

 

Strasys Continuous Build 3D demonstrator. (Stratasys)

A: Has 3D printing got any faster?

SS: They can now produce these parts faster and much larger. Our second demonstrator – the Continuous Build – launched in May 2017 is designed to produce parts in a continuous stream with only minor operator intervention. This platform is composed of a modular unit with multiple 3D print cells, working simultaneously and driven by a central, cloud-based architecture. Fathom, one of our North American beta customers with expertise in additive technologies, have a six-cell configuration in-house at FATHOM which dramatically increases their throughput. Our Continuous Build 3D Demonstrator offers the chance to use FDM for not just a hundred ‘just-in-time’ parts, but for 1,000+ parts on-demand. This significant step in increasing production rates and lights-out operation efficiency, drives lower costs per-part. 

Quality certification

3D printed Airbus aircraft components. (Stratasys)

A: What progress has been made to ensure that multiple AM parts each have the same quality? How are the regulatory authorities now viewing the safety certification of 3D printed parts?)

SS: In terms of quality and certification for the aerospace industry, we work closely with our partners to make this easier. We have half a dozen aerospace original equipment manufacturers (OEMs) that have written material specifications for our ULTEM 9085 and ULTEM 1010 products. These materials are delivered certified to each of those specifications which enables OEM’s to have the traceability and repeatability they require. We are expanding this beyond the early adopting OEMs, by qualifying the FDM process by working with America Makes, the National Institute of Aviation Research (NIAR) and the Federal Aviation Administration (FAA) to set a standard based on how composite material systems have been qualified in recent years. This will enable wider adoption throughout the supply chain. 

Plastics vs metals

A: How has 3D printing using plastics developed compared to additive manufacturing using metals? Are these being used for entirely different applications or is there any overlap?

SS: Every part needs to buy its way onto a plane. Over the past few generations of aircraft, much metal has been replaced by composite. The metal that remains is there because the part cannot be replaced by lighter materials due to the environmental requirements, or there is an inexpensive means of producing the part. However, some of the more inexpensive metal parts are gradually being replaced by printed plastic parts because the economics are more favourable than if they were to be metal printed. Parts such as engine components, that are driven to remain metal by requirement, is where there is an opportunity for printing metal. So, there isn’t much application overlap. We are continuing to push the boundaries with composite printing. As we do so, we may start to find additional opportunities to replace metal with composites, but that remains to be seen.

One advantage with plastic printing is that many of the first parts printed are low criticality. The lower criticality of these parts has made them easier to certify, so we’ve been able to find the qualification and certification processes that will be needed for large scale adoption. Whereas with metal printing, we’re focused on high criticality parts. Currently, metals processes are still maturing and the target applications are more critical. In the coming years, as we pursue those more challenging parts to certify, we’ll have laid the groundwork with plastic. 

Composite combination

A: Is 3D printing competing with composite manufacturing in any areas?

SS: Considering the materials and systems we have in development today, 3D printing isn’t so much competing with composite manufacturing but rather converging with it. Traditional composites manufacturing approaches offer strength, stiffness and are lightweight but the parts can be difficult to make, often labour intensive and limited to relatively simple geometries. Our 3D printing technologies provide design freedom and automation.

Our third demonstrator, the Robotic Composite 3D Demonstrator, is of significant interest to the aerospace industry. Also unveiled in August 2016, it is designed to bring aerospace’s strong, lightweight material systems of choice, carbon fibre composites, into 3D printing. Coupling the properties of the material with the design freedom and automation of 3D printing enables the optimisation of part design, and reduced part cost due to reduction in labour and scrap driven by automation.

By coupling traditional composite materials with advanced 3D printing approaches, we can mitigate traditional composites manufacturing challenges and come forward with 3D printed composite parts that are even lighter in weight and less expensive to manufacture. This is why we’ve had such strong interest in the Robotic Composite 3D Demonstrator from the aerospace industry. Being able to optimise structure in three dimensions, rather than layer by layer, is revolutionary for composites manufacturing.

OEM enlightenment

 

Stratasys has become Airbus’ supplier for serial production of 3D printed polymer parts for the A350. (Airbus)

A: Has the attitude of OEMs changed with regards to 3D printing?

SS: We have been in close conversations with the OEMs of this industry for more than a decade. Aerospace OEMs have recognized the value in the technology, and have pulled for the manufacturing advancements you are seeing today. Many of the early adopters in aerospace have kept their developments quiet to capitalise on the competitive advantage they gain from utilising the technology to its full benefit. As some of those market leaders begin to speak more publicly about what they have accomplished, it has opened some additional eyes to what might be gained from additive manufacturing. 

Take Airbus for instance. Our relationship with the company stretches back to several years, as we collaborated with them to prove feasibility on FDM technology for flight-ready parts. This collaboration led to the qualification of our FDM ULTEM 9085 material for the production of alternate parts on the initial Airbus A350 XWB deliveries. This summer Stratasys Direct Manufacturing, a subsidiary of Stratasys, was announced as Airbus’ supplier for serial production of 3D printed polymer parts for use on the A350 XWB.

By sharing our customers success stories with the wider industry, we hope to help many others understand the vast applicability of the technology. These close relationships also help us to create new solutions that are directly targeted at the needs of the OEMs.

Stratasys Fortus900mc printer. (Stratasys)

A: Have there been any recent technological developments (materials, components, technology) for 3D printing?

 SS: The most notable development of the last 12 months for the aerospace industry is the recently launched Fortus 900mc Aircraft Interiors Certification Solution. Announced at the 2017 Paris Airshow, this new 3D printing solution is based on the Fortus 900mc Production 3D Printer, and designed specifically for producing aircraft interior parts which will need to meet stringent FAA and European Aviation Safety Agency (EASA) certification requirements. We’ve incorporated the FDM ULTEM 9085 material and a new edition of the Fortus 900mc Production 3D Printer with specialized hardware and software, which is designed to deliver highly repeatable mechanical properties. The qualification is now underway with the NIAR and the National Centre for Advanced Materials Performance (NCAMP) and is planned to be completed by September of this year.

Remote repairs

A: There has been much talk about using local 3D printers for creating spare parts for aircraft needing repairs at remote maintenance repair and overhaul (MRO) sites. Is this a practical idea, given that these parts will need to safety certified?

SS: Practicality is always an issue, especially if the MRO site is so remote. However, our newly launched Fortus 900mc Aircraft Interiors Certification Solution offers a chance to overcome this problem. To ensure that a part meets stringent safety requirements the first version produced must be equivalent to the thousandth. Establishing a standard, such as what we are doing with this solution, mitigates this risk considerably and begins to make digital inventory and the on-demand printing of spares practical. We are working closely with America Makes, NIAR and NCAMP to develop a comprehensive qualification of the process. The resulting material and process specifications and design allowable data will be directly leverageable when MROs or operators seek certification.

Challenges

A: What challenges remain for 3D printing?

SS: Process repeatability is the key. We’ve driven the F900mc to achieve the necessary levels and we’re designing systems like the Infinite Build 3D Demonstrator from the ground up to meet those requirements but any equipment or process for use in a production environment will need to demonstrate this repeatability. We’re now defining the qualification processes and standards so that we can move largely experimental technologies to accepted and industrialised technologies.

 A 3D future

A: How do you see 3D printing for aerospace developing in the future?

SS: We expect to see the initial interiors use-case that has matured with the F900 to expand dramatically, both in the OEM space and with the aftermarket. We’ll see more custom interior parts and printed spares very soon. Beyond interiors, 3D printing will move outside the cabin, to higher strength parts with composite materials and to functionally-designed materials for special purposes, such as radiation shielding or electrical conductivity. All of these trends are picking up steam.

Bill Read
11 August 2017

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