Plane facts

While the complexities of aircraft seating design seems to make it an ideal candidate for rapid manufacturing, there is still a development gap

Aircraft seating designs are often specially made for particular airlines. Product differentiation, innovation, and prestige are very important, and they are willing to pay for them.

There are generally only a few seating units between an airline’s premium section and the rest of the aircraft, and there is much variation due to their unique position in the tapering aircraft cabin. All of these configurations need to be designed, made and delivered within very short timescales, and there needs to be a great deal of confidence that the product meets the demanding requirements of the airlines and the aircraft manufacturer.

The complexity of seating design and the variation among the different configurations can dictate the manufacture of these low-volume components. For this, the economies of manufacturing suggest that reducing tooling requirements can cut the cost of parts.

This high-value, low-volume approach to production is a typical application for rapid manufacturing (RM) technologies. The potential to reduce lead time and eliminate tooling while producing high-tolerance parts could have significant commercial benefits for the business.

Yet there are many challenges facing the more widespread use of RM technologies in this sector of the aerospace industry, and if we want to increase their implementation we must be ready to address these issues.

Contour Premium Aircraft Seating (CPAS), is part of the Premium Aircraft Interiors Group (PAIG) that comprises a number of companies involved in the design and manufacture of aircraft interior components such as seating, furniture, galleys and lavatories. In my experience of RM applications in this industry, I have observed that it is currently most feasible for small, non-cosmetic and non-structural components.

For metalwork, highly-styled parts can often be expensive to machine due to complicated geometry. Although RM allows the production of low-volume and geometrically unconstrained parts, there are still additional finishing operations required to finalise the part.

For larger metal parts, the build time and envelope limitation of current RM machines does not offer significant advantage over conventional machining. And for structural parts specifically there isn’t yet sufficient understanding of build parameters to ensure repeatability and consistency, or to enable up-front engineering analysis.

For plastic materials, small components are difficult to produce by vacuum forming and are made in quantities that do not justify other tool-dependent processes such as injection moulding. This makes RM particularly applicable. For larger components, RM will have to compete with vacuum forming in both time and cost.

The biggest challenges facing the more widespread used of RM and rapid prototyping (RP) are the properties of the available materials, the information and understanding of them and the process variables.

Although RP materials are available in a wider range of properties than those for RM, the manufacturing process is totally different. Rapid prototypes are usually produced on machines with different capabilities to those intended for final manufacture.

Consequently, RP parts may be representative of the nominal design, but not necessarily production tolerances, limiting their application for accurate fit testing or the assessment of production mechanisms.

If RM techniques could be used to process RP materials, then the use for rapid prototypes will be significantly increased, and design and manufacturing process could potentially be streamlined.

There appears to be a lack of readily-available, high-strength, low weight, non-flammable and predictable RM materials, and the industry is continually developing new polymers specifically to meet this challenge. But there is little justification for RM users to spend time and money on experimenting with new processes to compete with the long established, highly-regulated, customer-driven — although tooling-intensive — manufacture of composite components.

Researchers say that true RM is still up to 10 years away, and I wouldn’t disagree. Currently, RM applications are limited to small and non-structural plastic and metal parts, but when these limitations are overcome, there is the potential for the acceleration of the product development process for complex mechanical products.

Tim Steward is a KTP Associate in New Product Introduction (NPI) for Contour Premium Aircraft Seating