LOT Polish Airlines has adopted 3D-printed arm caps for the economy class seats in its Boeing 737 fleet, marking another milestone in the use of additive manufacturing (AM) for aircraft interior components.The arm caps, designed and produced by AM Craft, address durability issues and supply chain challenges that led to frequent part shortages and failures with traditionally manufactured components.Addressing Supply Chain and Performance Issues Maintaining a global fleet presents significant logistical challenges, particularly for components prone to wear and tear.
Arm caps, which experience constant use in aircraft cabins, often degrade due to the separation of the rubber surface from the injection-molded frame.The original parts also suffered from frequent breakage at the seat attachment point.Procuring replacements through traditional supply chains proved increasingly difficult for LOT Polish Airlines, leading the carrier to explore alternative solutions.
Top view of arm caps showing (left to right) the part being replaced, the unpainted 3D printed equivalent, and two colors of the final printed part.Image courtesy of AM Craft.By leveraging Stratasys material extrusion 3D printers, AM Craft redesigned the arm cap as a single-piece structure, eliminating failure points associated with multi-part assemblies.
The material of choice was ULTEM 9085 filament, a high-performance polymer known for its flame, smoke, and toxicity (FST) compliance. he new design also strengthens the seat attachment area, reducing the likelihood of breakage.To ensure a high-quality aesthetic finish, AM Craft used a specialized smoothing and painting process, color-matching the arm caps to LOT’s cabin interior.The final cosmetic finish was achieved using Mankiewicz’s ALEXIT coating system.
In total, 1,200 arm caps were produced and delivered with an EASA Form 1 Airworthiness Certificate.3D Printing in Aviation Stratasys has played a pivotal role in integrating 3D printing into aviation.While the company has been involved in the sector since its beginnings, it made headlines roughly a decade ago when Airbus incorporated over 1,000 3D-printed parts into its A350 XWB aircraft.
Stratasys’ expertise in high-performance thermoplastics, particularly ULTEM 9085, has enabled the production of lightweight, FST-compliant components for commercial aviation.Stratasys further solidified its presence in the aviation sector through strategic investments, including its partnership with AM Craft.In 2024, Stratasys invested in AM Craft to accelerate the production of certified polymer parts for aircraft interiors.
This move followed Stratasys’ earlier collaboration in Additive Flight Solutions, a joint venture with Singapore Airlines’ SIA Engineering, aimed at leveraging 3D printing for aircraft maintenance, repair, and overhaul (MRO).The aviation industry has increasingly turned to 3D printing to address supply chain disruptions and improve the performance of aircraft components.According to AM Research’s quarterly data services report, the aerospace industry experienced 9.6 percent growth year over year in Q3 of 2024. AM Craft, an EASA Part 21G-approved aviation supplier, has been expanding its capabilities in this sector, producing certified flight parts for airlines worldwide.
The company operates a global distributed production network, combining in-house expertise with independent partners to deliver certified components at the point of need.Bottom view of arm caps showing (left to right) the part being replaced, the unpainted 3D printed equivalent, and two colors of the final printed part.Image courtesy of AM Craft.
AM Craft has steadily increased its presence in the commercial aviation sector.The company has previously collaborated with Finnair to produce 3D-printed Passenger Service Unit (PSU) fill panels for the airline’s Airbus A320 fleet.In 2024, AM Craft partnered with alphacam to expand its production capabilities in Germany, strengthening its footprint in key aviation hubs such as Hamburg.
LOT Polish Airlines’ adoption of 3D-printed arm caps mirrors trends taking place in mobility overall, most often for supply chain resilience.While aerospace is among the most mature in terms of AM adoption, MRO trends have been less public due to the competitive and secretive nature of the industry.However, the rail sector is much more public, with the European network Mobility goes Additive boasting “over 150,000 parts with 700 different applications [having] been printed at [Deutsche Bahn] using 12 different AM technologies.” The automotive repair sector has been more reluctant to adopt the technology, with 3D printing slowly being pushed by such companies as Auto Additive, Autentica, Würth Additive Group, and others.
Regardless of sector, it seems as though MRO for supply chain resilience may be the gateway to widespread 3D printing adoption.Once that ramps up, improvised 3D printing of point of use may not be far behind—if the military’s use of AM is any indicator.Feature image courtesy of km30192002 on Flickr.
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