Loading and unloading of a turning center

The operator enters the diameter of the parts to be processed and starts the robot and the machine. The machine controller sends the specific data for the workpiece to the robot controller. The robot controller then calculates the positions to which the robot must be moved. Using a sensor, the KR 45 measures the height of the pallet stack and then the length and diameter of the first blank on the uppermost pallet. These values are used for the gripping operation. A second measurement sequence is carried out, in which the system works with a higher accuracy of ±1 mm. The KR 45 does this by placing the blank on a V-shaped slide with an end stop. The robot now determines the length and diameter of the blank and compares these values with the data specified by the machine controller. If the data agree, the robot places the part in the clamping device of the turning machine. If the data do not agree, a fault message is generated. Once the first side has been machined, the robot rotates the workpiece. Once the second side has been completed, the robot places the workpiece on a pallet. While the turning center is working, the KR 45 loads the next blank into the positioning station. Using a transfer fork, which it picks up by swinging its arm overhead and to the rear, the robot takes hold of empty blanks pallets and places them on the pallet stack for finished parts.

• KUKA KR 45 robot
• PC-based KR C1 robot controller, including control panel with Windows interface
• Three-finger gripper specially designed for this application, with exchangeable gripper jaws
• Safeguards
• Robot programming
• Assembly
• Commissioning
  
  

The complete robotic cell was supplied by KUKA systems partner Ch. Stein AG Automatisierungstechnik, based in Aarau, Switzerland.

• Process reliability
  
  The system ensures process reliability by means of rapid, error-free communication between the robot controller and the machine controller, and the precision with which the robot handles and measures the parts.

• Short setting-up times
  
  Two pairs of manually-changed gripper jaws, each covering half the range of blank diameters, allow Dihart to adapt the robot quickly.
  
  
• Increased productivity
  
  Due to the level of flexibility and process reliability achieved, Dihart has increased its productivity significantly without the need to enlarge the workforce. The high degree of automation involved in the manufacture of precision tools is of significant economical importance for the company.
  
  
• High precision
  
  Positioning of the robot at the taught points is accurate to within 0.15 mm. A precondition for precise handling is the reliable transfer of all relevant data from the machine controller to the PC-based KUKA robot controller KR C1.