When Mürdter Metall- und Kunststoffverarbeitung GmbH won a contract with a system supplier to the automotive industry to manufacture door side linings for an airbag system, it was clear that an automated solution would be needed. The main requirements on the handling systems were a long reach, both horizontally and vertically, and a high degree of flexibility.
The work is carried out by two standard KUKA robots of type KR 30 and three KUKA shelf-mounted robots, of type KR 150 L110 K, positioned on the machines. In an efficient job-sharing process, these robots provide the door side linings with woven grids, thread inserts and labels, before processing them in a laser cutting system. The shelf-mounted robot situated at the beginning of the process takes a woven grid from a rotary table and inserts it in the moving half of the injection molding machine. To handle the woven grid, the KR 150 L110 K uses the mechanical side of its combination gripper. In the same cycle, it also takes an injection-molded set of door linings out of the fixed mold half using the pneumatic side of the gripper. It then passes the two parts, joined by the woven grid, to an imaging station for quality control. While the robot is still holding the tested part in its gripper, it picks up the next woven grid with the other side of the end-effector. It then transfers the door side linings for inductive heating of the thread inserts. The KR 30 robot working in parallel with the KR 150 L110 K feeds the cylinders of the unit with the thread inserts, which it has previously taken out of sorting pots with its suction gripper. To do this, the robot gradually turns the end-effector in order to be able to pick up eight thread inserts individually in one cycle. It then passes them on as a group to the cylinder. After this, the third robot, again a KR 150 L110 K, fetches the door side linings with its vacuum gripper and places them on the rotary table of the laser cutting unit, in which another KR 30 processes the airbag area of the parts. The KR 150 L110 K picks up a finished set and pushes it against a label printer that provides each part with a bar code. It then lays the set onto an intermediate support. From there, it is picked up by the first KR 30 and put on an outward conveyor belt. The third KR 150 L110 K is currently unemployed; it is waiting for a second injection molding machine to be integrated into the process.
System components / Scope of supply
- Three KR 150 L110 K shelf-mounted robots
- Two standard KR 30 robots
- Five PC-based KUKA robot controllers, including control panel with familiar Windows interface
- Conveyor system
- Rotary indexing table
- Linking of the robots for control purposes
- Robot programming
- Sensor systems
- Label printer
- Configuration and installation of the inductive heating unit and the laser cell
- Implementation of the corresponding interfaces
- Safeguards
- Commissioning
Supplied by the KUKA system partner DAT Automatisierungstechnik GmbH, Pappenheim, Germany.
Results / Success
- Space saving
The shelf-mounted robots save space by carrying out their work from above. From this vantage point, they are able to load and unload injection molding machines and transfer the molded parts to other stations for further processing. The resultant higher level of automation leads to shorter cycle times, lower personnel costs, and increased productivity. Because of their aluminum construction, even the large shelf-mounted robots are very light in relation to their potential payload, and thus can be mounted on the machines without difficulty.
- Long reach
The robots – in particular the three shelf-mounted robots, which with arm extensions can reach as far as 3500 mm – fulfill the requirements with regard to long horizontal and vertical reach.
- Greater flexibility
Should it become necessary to extend the system, KUKA robots are more flexible and thus more cost-effective than alternative devices.
- New robot generation
The KUKA robots belong to the Series 2000 robot generation, which stands out against its predecessors above all due to its optimized kinematics. This results in higher speeds and payloads, as well as a work envelope which is 73% larger than before.
