Dr Misael Pimentel outlines a collaborative project which is set to unlock more efficient manufacturing routes for aerospace components, enabling key industry drivers such as reduced emissions, remanufacturing, and more resilient supply chains.
Landing gear systems are one of the most crucial components of an aircraft and provide the principal support when parked, taxiing, taking off or landing. With such a critical role within the overall operation of the aircraft, it is no surprise that the manufacture of the parts within the systems are met with strict regulatory and safety requirements and, as such, the design and manufacture of the components are faced with several challenges.
Industry-wide, manufacturers across the world are looking at designs and methods of manufacture that result in reductions in weight, time, cost, stages of processing, and material and energy usage – cutting back on the cost of manufacture and supporting the race to net zero. However, for critical components, like landing gear systems, achieving such reductions in line with regulatory and safety requirements is difficult.
Traditionally, key aerospace parts, such as those within an aircraft’s landing gear system, are forged and then machined and this manufacturing process comes with a hefty cost. The system is such that manufacturers need to fabricate a die, buy tooling to forge the part, and then machine it to its final geometry, including features protruding from the main body. Because dies are usually tied to a specific component design, design changes to a feature position, for instance, can be very costly and time consuming since a new die has to be manufactured accordingly.
Leading aerospace companies including Airbus and Safran Landing Systems recently worked as part of a steering group led by the National Manufacturing Institute Scotland (NMIS), part of the High Value Manufacturing Catapult, on a new project aiming to offer a major sustainability boost. The project demonstrated the potential for cost and lead-time savings across the manufacturing of landing gear components by combining radial forging, additive manufacturing, and parallel kinematic machining technologies.
Funded by the Aerospace Technology Institute (ATI), the ‘Hybrid Direct Energy Deposition (DED) Sprint’ project partners included NMIS, Cranfield University and the Northern Ireland Technology Centre (NITC), Queen’s University Belfast, along with an industry steering group of more than 10 companies. The group worked to devise a new Hybrid DED process that will help overcome the challenges that manufacturers face in the expensive and time-consuming process of manufacturing such critical components that operate under harsh environments.
Looking to streamline and future-proof production, the partners developed a new method which combines the low costs and flexibility of forging, design adaptability of additive manufacturing, and increased accuracy and flexibility of parallel kinematic machines (PKM).
Unlocking new methods
With cost reduction and improved sustainability high on the agenda for aerospace engineers, a new approach to manufacture is essential. Using Hybrid DED methodologies to reduce tooling, forging, and machining requirements, we aimed to unlock benefits reaped by other industries that have felt out of reach for those operating within such harsh environments. By adding features directly onto forged and formed substrates using additive manufacturing, engineers can create a more efficient manufacturing process with less material waste. This also opens up opportunities for new repair and remanufacture methods.
The project was split into four work packages. As a result of the first two phases of the project, demonstrator components were delivered by both NMIS and Cranfield University, with NMIS’s demonstrator sent to NITC at Queen’s University Belfast, which focused on PKM. The final proof of concept phase then compared traditional and alternative Hybrid DED manufacturing routes, looking at how feasible this proposed, novel method was to industry.
The project was designed to incorporate the expertise of NMIS, Cranfield University and NITC at different stages of manufacture to fully understand the material usage, processing, and machinery, allowing us to progress a hybrid solution to bring to industry members. Work packages one and two were similar in that they both focused on the manufacture of the landing gear application, however the material usage differed within each. While Cranfield University explored 300M steel to deposit features onto forged substrates, at NMIS, we worked with dissimilar titanium alloys, depositing Ti-6Al-4V features onto Ti-5553 forged substrates. Some of the latter were forged in-house to comprehend the material limitations, challenges and opportunities when utilising radial forging technology. Working closely with Cranfield University and NITC, we combined learnings to explore the feasibility of the new route at each stage.
The manufacture of these components must stand up against rigorous regulations. As a result, Research and Technology Organisations (RTOs) investigated the mechanical properties and microstructure of the deposited features and how they interact with the forged substrates. The work performed fostered initial steps towards increased repeatability, confidence, and adoption of additive manufacturing across different sectors, leading to higher technology readiness levels, in addition to qualification and certification steps.
The intent was not to replace traditional methods. Instead, we hope to provide an alternative option that incorporates and matures current manufacture into a system that is more efficient when it comes to energy, material usage, cost, and lead-time. A key deliverable of the project was the assessment of those savings. We looked at comparisons between methods and the associated factors such as cost, CO2 emissions, weight, energy consumption, and lead-time. Another important factor was the buy to fly ratio and how, through additive manufacturing, we were able to make reductions in the percentage of waste material.
The beauty of the Hybrid DED process and the use of additive manufacturing means that repair and remanufacture of worn parts will be much more accessible. Instead of manufacturing a completely new die or a new part, the hybrid process allows manufacturers to utilise the part and material already there, bringing the component back into line with industry requirements and benefitting from huge savings in material, cost and lead-time through a much more sustainable option.
Although currently focused on the aerospace sector, the respective technologies and work developed are relevant for all parts and translatable across multiple industries including oil and gas, defence, space, and automotive.
Time for take-off?
We never intended to reinvent the wheel, yet as we brought manufacture into one hybrid solution, significant savings can be made to achieve a pathway for critical component manufacture to access modern techniques that are more sustainable.
Designing a more sustainable solution, cutting costs and time, reducing buy to fly ratios – these are not new problems for manufacturers on a global scale. Yet, while industry 4.0 and new technologies are unlocking new solutions, the accessibility of such varies from sector to sector and this can be incredibly challenging for critical components. If we are to achieve net zero targets and manufacture in a more efficient way, it is imperative that we collaborate and ensure that no industry is left behind.
Dr Misael Pimentel is a senior manufacturing engineer leading the Direct Energy Deposition Arc Theme alongside principal investigator, Stephen Fitzpatrick, additive manufacturing, machining and remanufacturing group lead at the National Manufacturing Institute Scotland, operated by the University of Strathclyde.