Swiss textile manufacturer Rieter runs spinning machines as long as 80 meters (262 feet) producing thread and fabrics. Robotic arms drive to precise points on the machine to reapply broken threads, but as the machines run, they heat up and expand by several centimeters. Rieter uses the API Radian laser tracker to document the length of their machines and automatically send adjustment information to the robot controllers.
Formulated very simply, many of the measurements carried out on the spinning machines of Rieter in Winterthur are concerned with the question of how long they are – because here, and in the other distance measurements in the machines themselves, we are dealing with fractions of millimeters under certain circumstances. Conventional measurement machines can be ruled out with machine lengths of 70 meters and more, even if they were available in such sizes: How do you bring such a giant onto a measuring machine? Mobile, laser-based measurement systems that can measure up to 80 meters help Rieter out here.
Starting from the center of gravity of the system, the length of a machine can thereby grow by centimeters when the machine temperature increases during the course of the operation. Because robots actually move about inside the machines during the operation in order to reapply broken threads at the individual spinning positions. Above all the spinning locations, and thereby over the complete length of the machine, it must thereby be ensured that the robot drives to exactly the position that it should reach in front of the spinning location. In order to document online how machines “grow“, they are measured every 5 minutes while in operation. Measurements to ensure this are carried out by Dipl. Masch. Ing. Martin Tobler, Calculation and Measurement Engineer in the Analytics department at Rieter, using mobile laser trackers that are set up directly between the machines. They not only measure the positions of the spinning locations, but also the rails on which the robots themselves hang. The tendency of the machines to expand in the linear direction must also be taken into account when choosing the fixed points on the floor for the set-up of the laser trackers.
In addition to the utilization of raw materials and a long service life, energy costs are an important factor in spinning machines. Up to 12 motors can be used in a single machine. The considerable length of the machines thereby presents a special challenge for its drives; if one end of a drive shaft of this length was set into motion, a different, time-delayed rotary motion would be found at the other end. Spinning machines are thereby fitted with a central drive that basically makes the multi-position simultaneous spinning process possible. Trackers help Rieter in the optimization of the alignment of these drive components, which increases efficiency and lowers energy costs.