Cambridge-based Marshall Aerospace and Defence Group (Marshall ADG) has turned to 3-D printing to create flight-ready parts at a fraction of the cost and time involved in using traditional manufacturing methods.

The company’s latest innovation programme is pushing technological boundaries to reduce weight and increase performance on its fleet of military, civil and business aircraft (www.marshalladg.com).

It originally looked at metal additive manufacturing as a solution, before discovering that Stratasys polymer technology — supplied by Derby-based SYS Systems (www.sys-uk.com) — could deliver the quality of materials it needed to meet industry regulations.

Marshall already has several pieces of 3-D printed ductwork flying on heavily modified aircraft, as well as holders for safety knives and switches for aircraft interiors, while producing specific ground-running equipment far more quickly and cheaply than aluminium alternatives.

Chris Botting — materials, processes and additive-manufacturing engineer at Marshall ADG — said: “When working 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 3-D printing fits perfectly.

“We also need to ensure that the ducting work produced will be approved by the European Aviation Safety Agency for flight.

“As a result, we are using the Stratasys Fortus 450mc and ULTEM 9085 resin — a tough yet light-weight 3-D printing material with high thermal and chemical resistance.

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

Having worked with engineers from SYS Systems, Marshall recently created a ducting adapter prototype for vital ground-running equipment — essential for providing fresh air to cool an aircraft’s avionics.

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

“We were then able to demonstrate that it had the potential to be 3-D printed in Nylon 12 material, which led to a significant cost reduction compared to machining the part out of aluminium, as well as a 63% reduction in overall weight.”