A Kuka robot stitches aircraft parts made of carbon-fiber-composite material, while they are in the mold.

Airbus Deutschland GmbH in Germany uses a robot to stitch together mats of carbon-fiber-composite material for aircraft components such as rudders. Complicating the task is the need for a 90° angle between the needle and the material at all times.

A Kuka KR 125 robot from Kuka Robotics Corp., Clinton Township, Mich., handles the automation, which can involve large part dimensions and 3D structures.

The robot sits at the top of a work cell in an inverted position on a 7-m linear unit.

To do its job, the robot finds and measures a mold carrier containing mats of material that operating personnel push into its cell. A lasermeasuring system sizes up the situation so the robot can adjust the sewing program to the carrier position. The six-axis robot then sews forms with convex and concave shapes.

While stitching the material pieces, the robot's manipulator arm uses different sewing heads swapped in with a quick-change system. A tufting head inserts the thread through the material without interlocking the stitches on the opposite side. This additional thread reinforces the material. A blind-stitching head joins different layers of material to each other, as does the backstitching head. However, the robot needs to access the material from below for the backstitch.

The KR 125's motions continually coordinate with the sewing head. For example, the robot leaves the programmed path but resumes work again from the previous position when a thread breaks or knots. Such interruptions happen frequently because needles are subject to heavy wear.

Once the robot stitches a form, the mold fills with resin and closes. This presses the resin into the sewn material and creates the completed component.

The company also uses the robot to sew pressure shells, wing elements, and sections of outer skin to aircraft structural members.

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Kuka Robotics Corp., kukarobotics.com