Aircraft wings are the most critical structural component of the entire aircraft and the precision fabrication of aircraft “skins” has become nothing short of engineering artistry. Airplane fuselages and wings for the aviation, space and defense industries are made of 1 mm-5 mm thick contoured aluminum or aluminum composite and designed to be both strong and lightweight, a challenging combination that’s been mastered thanks to computer assisted design and automation in manufacturing.
Liné Machines in Quebec, Canada designs, fabricates, and engineers one of the most innovative machines to produce these large aircraft skins; the Flexitool tooling system. Imagine a supersized bed of nails where every “nail” is actually an electromechanical actuator with an Animatics SmartMotorTM servo attached to its base. Flexitool can exactly match the unique contoured shape of almost any large metal panel (with support equivalent to a hard tooled fixture) for further processing such as milling, inspection and laser scribing.
Initially, Liné Machines designed a system composed of pneumatic actuators to contour to the geometric dimensions of the metal panels but procurement and machine integration with key suppliers became an issue. The original design meant a separate drive, motor and actuator for each position, as well as a large control cabinet near the machine. Creating Flexitool with 324 different shapes and position configurations with this method required 324 separate drives, motors and actuators. Instead, Liné Machines decided to create their own turnkey solution.
Liné Machines redesigned Flexitool using SmartMotor servos coupled to their own custom mechanical actuators. With SmartMotor’s integrated design, the Flexitool tooling system accomplished the same 324 positions with only 160 actuators and SmartMotor servos, resulting in a 49% reduction in parts and floor space.
“We used the integrated SmartMotor because having separate controllers, drives and motors was limiting our capabilities. Now the connection is much simpler, and it’s easier to increase or decrease the number of tooling structures for each Flexitool ordered” said Claude Sven Zurbuchen, Lead Product Development Engineer for Liné Machines. This Flexitool system is 3 m wide by 5.6 m long but the system can be customized to the customer part dimensions and can range up to 6 m wide and 20 to 50 m long.
Each SmartMotor has 32 Kbs of memory and can be loaded with up to 8,000 preset positions allowing for thousands of preset configurations and giving Flexitool the ability to match almost any panel’s contour. Because airplane panels are often short- run, made-to-order parts, the added flexibility also saved the cost of having multiple hard-tooled structures. In addition, the final quality of the panel pieces improved compared to a hard tooled fixture by holding the precision contoured shape to prevent warping during the milling and laser scribing processes. Flexible and fast changeover between panels was integral for streamlining the production process to create greater throughput.
Animatics’ Combitronic technology provided another key benefit. When raising or lowering any panel on the Flexitool tooling system, all of the actuators needed to move in sync vertically from any position to prevent warping. Typically, either Ethernet, Profibus, DeviceNet or CANopen handled the communication between motors. However, none of these networks alone allowed Flexitool to talk to multiple motors simultaneously; it must address each device separately. While this wouldn’t be a problem with two or three motors, it was an issue with 160 actuators. Simultaneous addressing with conventional methods would have caused delay and the risk of warping the panels and sequential addressing would have added propagation delays. Combitronic allowed for group addressing and global addressing, creating the ability to communicate with all 160 servo motors in a completely synchronized way with no delay in execution.
Filed Under: Aerospace + defense, Actuators, Motion control • motor controls, Motors • servo