Shining the light

Shining the light
Shining the light

One technology that has speeded up composite part production in aerospace manufacturing is laser template projection. Ed Hill discovers more about the LaserEdge system from its developers Virtek.

One technology that has speeded up composite part production in aerospace manufacturing is laser template projection, employed by Bombardier at its CSeries wing manufacturing facility in Belfast. Ed Hill discovers more about the LaserEdge system from its developers Virtek.

Processes such as cutting, placement and lay-up on mould tooling can add substantial time to the production of carbon composite parts in aerospace applications, particularly when dealing with large structures such as wings.
Virtek's LaserEdge templating system enables operators to construct composite parts without the use of bulky physical templates that have to be manually lifted on and off the mould while ply material is fixed in place. The system projects a laser outline of the part to guide the operator attaching the plies.

LaserEdge was first developed in Canada by Virtek (part of the Gerber Technology Group) in the early 90s. A patent acquired for production in composites followed in 1997.

Early applications mainly revolved around military aircraft but the advantages of laser templating soon became obvious for civil aircraft producers keen to exploit the ‘lightweighting' characteristics of composite materials.
“Traditional lay-up processes involve an operator placing a template and using a grease pencil to mark around the pattern,” Sean Francoz, senior product manager at Virtek, explains. “Positioning pins fix the template in place. If the template is a complex shape there is a lot of potential for human error. There is also the added problem of building and maintaining templates, storing them and the strain on staff having to lift these sometimes large structures on and off the mould. These are all very costly and time consuming elements eliminated by using LaserEdge.”

Hitting the target

Laser projection uses retroreflective targets positioned around the edge of the mould tool to orientate the projected shape before lay-up begins. The targets reflect light directly back to the source allowing the system to measure the position of these points highly accurately. This means speedier set-ups and removes many of the non-value steps in the process.

Virtek has worked closely with its customers to enhance the performance of its LaserEdge system such as shifting from red to green light making it easier for operators to see. There have also been developments in the operator interface such as projected icons used to control the system.

Peter Richter, vice-president business development at Virtek explains: “These are symbols that the operator can interact with projected onto the work surface of the tool. It enables you to move to the next projection, recalibrate and verify accuracy and project part numbers during ply lay-up. On a large part such as a wing skin the operator can stay at the tool and not have to go back and forth to a computer or use a remote. It means the whole process of lay-up is much faster.”

LaserEdge takes 3D CAD model data to create the required projections. Additional programmes such as Virtek Laser Kit and Planner mean ply outlines can be produced on the cutting table and then the lay-up sequence can be simulated and followed by the operator showing each step of the composite part's assembly. It also allows for better integration between the engineering design office and the workshop floor.

“There can be many plies associated with each template so it's very easy for errors to take place,” Francoz continues. “LaserEdge means you are sure you are projecting the right shape in the assembly sequence.”
Richter adds: “Cycle times for design changes can also be implemented much quicker. Alterations can come from the design department to the workshop floor directly and be projected onto the mould. You don't have to make new template drawings and templates which could take weeks. An update – once it has undergone the necessary approvals – can be sent to the shopfloor within minutes, reducing the cost of change management dramatically.”

Going the distance

So how does the system tackle projecting over large distances such as those needed for wing part manufacturing?

“Our lasers are ‘eye safe' this means if an operator accidently catches a reflection of the beam or it hits the eye directly they are protected,” states Francoz. “However, this does limit the beam's power and visibility can become an issue. We offset this by optimising the focus of the laser automatically. For example, with a contoured shape the centre of the object is likely to be closer to the light source compared to the edge. So the focus needs to constantly adjust as the operator moves to different work areas around the part.

“Additionally our Focus of Attention feature means when the operator is trying to put a large ply on to the mould, as well as the larger projected outline, the system can focus down to important areas such as the edges where detailed lay-up is taking place. This guarantees a perfectly bright, stable image where it counts.”

Laser projection can be found in a diverse range of aerospace applications. Aside from composite part production it is also used in the final assembly phase, hole location, paint mapping and masking and inspection.

“It works extremely well in an industry where you need to place things accurately in 3D space with little or no reference points over long distances. Virtually every component made from carbon composites can use this system from fuselages and structural beams to smaller parts such as a helicopter rotor blade yoke. In final assembly it is used to place brackets accurately for fuel lines, hydraulic systems and wiring looms. It is also used to create a controlled sequence of visual inspection,” Francoz asserts.

Collaboration between Virtek and its OEM customers has been crucial to the development of LaserEdge. The company has a 15 year relationship with Bombardier, also providing systems for its plants in Canada and Mexico. Virtek's laser systems are supplied to most of the major aerospace manufacturing companies and it is currently being used on the Boeing 787, Airbus A350 and Learjet 85 programmes. New and varied aerospace applications seem inevitable.

“Customer feedback is carefully considered and we proactively find out where they would like to see improvements,” Francoz continues. “We value these relationships very highly. They are close collaborative partnerships which also enable us to validate new features in our products.

“We have released a new system called the Iris Spatial Positioning System (SPS) which has features that extend the applicability of laser projection. We expect it to bring the efficiency of the system into areas of manufacturing where previously it would have been impossible.”

He concludes: “LaserEdge means precision is assured, recorded and verified. It enables more traceability to be introduced into the lay-up process. You can record which operator placed the material, where, when and how they did it and how long it took. As we move into the future where traceability and process control in aerospace manufacturing becomes ever more vital our system facilitates this. It would not be possible with physical templates and at the production rates now required in the industry.”

www.virtek.ca

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