Handling of molds with KR 500

The cores, which weigh up to 260 kg and are up to 1135 mm high, are moved on a conveyor from the furnace to the pickup station of the first robot. A light barrier sends a signal to the KR 500 when a sand core is present. The robot determines its exact position using a laser. The robot then picks the core up using its universal clamping gripper and dips it into a bath of water wash to a defined depth. This protects the sand from the molten metal, thus preventing burning-in on the product. The end-effector used on this robot can be converted to four different families of sand core by changing the gripper jaws manually. After dipping the core into the bath, the KR 500 lifts it out again and transfers it to the apron conveyor of the drying furnace. During this process the robot carries out rotational motions to allow the wash residues to drip off, thus preventing “runs”. For types of core to which the wash has to be applied only on certain surfaces, the robot applies the wash using a flood lance. Once on the conveyor, the sand cores pass through the 170 °C drying oven and a cooling zone. They are then picked up by the second KR 500, which has three different tools, and set down on pallets. For the most common cores, the company uses a so-called Liftboy, which is lowered into an aperture in the top of the individual core and expanded by means of compressed air. Like the first robot, this one also first employs a laser beam, this time to find the aperture. Other cores are provided with a lifting eye which makes it possible for the KR 500 to pick them up using an additional gripper. The third end-effector is a plate gripper which clamps the cores between its jaws.

• Two KUKA KR 500 robots
• Two PC-based KUKA robot controllers, including control panel with familiar Windows interface
• Engineering and delivery of the grippers
• Engineering and delivery of the tool changing tables
• Magazine for safety brackets, which are used as spacers between the sand cores
• Immersion, flooding and palletizing programs for 20 types of core
• Robot programming
• Safeguards
• Adaptation of the new equipment to the existing systems
• Participation in development of the gripper jaws
• 3D simulation of the system as part of a comprehensive presentation of the project at Gienanth’s parent company
• Commissioning

• High flexibility
  
  One of the decisive arguments in awarding the contract was the KUKA robots’ flexibility, which is based on their six axes and their resulting freedom of movement.
  
  
  
• Short cycle time
  
  The complete cycle time, from picking up the sand cores to setting them down, is from two to three minutes, depending on the product. The robots have no problem in maintaining this cycle time, which is determined by the controller of the continuous furnace.
  
  
  
• Greater cost-effectiveness
  
  With normal utilization, the company calculates that the system will have paid for itself in three years. Its cost-effectiveness is based on higher productivity. Moreover, an alternative solution would have consumed almost ten times as much energy as the robots. Other important economic factors are reduced personnel costs and the high availability of the robots and their periphery – about 98 percent.
  
  
  
• Higher quality
  
  The quality of the automatic handling is significantly higher and more uniform than with manual handling.