With growing composites use, engineers are making more extensive use of simulation to better understand manufacturing operations and how design decisions impact production. However, as both design and manufacture are constantly evolving, design for manufacturability is a bit of a moving target. Companies continue to examine the range of composite materials to see how they fit into both the aircraft and their manufacturing processes.
The transition to composite materials further increases the link between design and manufacturing not only because composites are new materials to most aircraft engineers but also because there are far more variables in composites manufacturing.
Designers will see more trade-offs than they faced with aluminum and other metals. Perhaps more importantly, those variables are closely intertwined with manufacturing processes.
The age-old challenge of designing something that can be manufactured efficiently looms larger than ever. Some companies are responding by having the engineers who design the parts spend time in the factory actually building those parts.
"There is no better way to improve an engineer’s design skills than to have them feel the pain of the designs they inflict on the manufacturing floor," said David Hornick, Director of Advanced Composite Technology for Gulfstream Aerospace.
Another way to tighten the link between design and manufacturing is to let design engineers run simulations that show how their designs will be produced on the plant floor. That often helps engineers determine which trade-off makes a design easier to produce.
"The use of simulation tools enables true design for manufacturing," said Doug Decker, Technical Fellow at Northrop Grumman Aerospace Systems. "The tools are used in validating assembly installation paths, assembly flow, human impacts and ergonomics, and tolerance analysis. This allows the design teams to validate the planned processes prior to engineering release."
Whether they go onto the shop floor or use simulation tools, engineers can help companies improve productivity by understanding how their decisions impact manufacturing. For example, many composite production machines have limits in how they can handle corners. Often, this limitation means that corners sharper than 45° require the use of tabs to hold materials in place while the equipment stops and repositions itself to complete the turn.
These tabs can have an impact on the critical weight parameter. If design engineers understand these limitations, they can often reduce the angle of corners and eliminate the need for tabs.
Alternatively, they can factor their weight in. Design tools are being upgraded to make it simpler for engineers to understand the trade-offs.
"Details like this have to be taken care of by design teams so they design parts that are truly manufacturable," said Olivier Guillemin, Product and Market Strategy Director, Vistagy Inc. "Blocks in our design software now have a number of functions that help design teams target their company’s manufacturing processes, highlighting places that will cause problems."