Automated carving of prototype tires
Prototype tires generally have their tread carved by hand. But at tire giant Continental, they like to do things differently. High-precision Stäubli robots handle the difficult task of carving with a hot blade, achieving maximum accuracy and reproducibility, and working faster than ever before. A hi-tech solution based on a wealth of expertise.
The engineers at Continental in Hanover are constantly designing new tire models for cars and trucks, which they produce in short runs for testing purposes. The profiles of the first prototypes are traditionally carved by hand from slicks using hot-wire tools. A time-consuming process that can take up to 40 hours. It starts with dimensioning and marking before the actual carving process can begin.
Continental is therefore striving to automate the various steps in prototyping. Working in close collaboration with the tire manufacturer, the expert team at system integrator Preccon Robotics in Bayreuth have developed a highly innovative robot cell for tire carving.
The robot as dimensioning and machining tool
On the sophisticated Preccon production line, a high-precision Stäubli RX160 industrial robot is in complete charge of the dimensioning, marking, carving and drilling of automobile and truck tires. At the same time, the robot acts as a totally reliable measuring device. Thanks to its superior drive technology and above-average rigidity, the RX160 meets the stringent requirements of this application for accuracy.
The slick to be processed is clamped onto an external seventh axis which is configured as a turntable. The robot controller directs not only the three-dimensional pathway of the carving tool in the gripper but also the fully synchronized rotation of the tire by means of the seventh axis during the dimensioning and carving. In order to determine the depth to which the tool will cut, the robot always starts by sizing up the contour of the tire blank. For this purpose, the laser is picked up by the gripper and calibrated on a ceramic ball before making multiple passes over the rotating tire. On the basis of the data secured in this way, the tracks generated in the CAD model of the offline programming system are automatically adjusted before they are fed into the robot controller.
The carving begins with the robot picking up the cutting tool from the knife station. This has been parameterized for the respective process path. After determining the Tool Center Point (TCP) via the image processing system