| Starting point / Task definition |
 | | The production of proton exchange membrane fuel cells |  |
The drive towards greater cost-effectiveness and improved quality provided the impetus to search for suitable automation options. In order to be able to modify individual processing stages, and therefore to find the most practical and effective automation solution, ZSW placed great importance on the flexibility of the system. |
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| Implementation / Solution |
With its absolutely accurate calibration, the KUKA KR 60 HA robot was best able to meet the standards set by ZSW.
Its task is to assemble the sensitive components of a cell with great accuracy and precision. During a first stage, it takes up a bipolar panel and deposits it in a retainer. The panel is usually made of a graphite composite, and the robot fits a sealing frame to it which it has taken up from another magazine. The dual vacuum gripper now makes it possible, without replacing the gripper, to take hold of a piece of gas-permeable graphite paper from a device called the “vibrator.” The vibrator separates the graphite papers and brings them into the correct position so that the robot can grip them cleanly. The individual gas diffusion layers are separated from each other by a thin piece of paper. The robot peels off this paper on a suction device. In a subsequent stage, it uses a laser to check whether the separating foil really has been removed. It also determines, by means of a distance measurement, whether it really has only picked up one single sheet of graphite paper. The robot then fetches a proton exchange membrane and sets it onto the graphite paper, before picking up another sealing frame and gas diffusion layer, to which it then fits a bipolar panel and, finally, a cover seal. The cell is then complete. |
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| System components / Scope of supply |
- KUKA KR 60 HA robot
- Double vacuum gripper
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| Results / Success |
High precision
The KR 60 HA from KUKA is calibrated with absolute accuracy. In other words, it works extremely precisely thanks to its excellent positioning accuracy and precise path characteristics, thus avoiding inaccuracies which can render the cell useless. This is a unique feature which no other robot manufacturer is able to offer.
Greater cost-effectiveness
The robot checks its own work during the process and, whenever necessary, automatically reacts to errors.
A “stack” contains between 10 and 80 cells. The robot takes approximately two minutes to produce each cell. It is therefore able to produce 80 cells within a production process, i.e. within less than three hours. A human worker takes a whole day to produce just 40 cells.
High flexibility
The main concern of ZSW is to find out which process stages are required in the first place in order to automate fuel cell production, and how these individual stages can be solved. The aim is to find the most reliable and cost-effective way to transfer the individual working stages to a machine. At the same time, however, research also needs to be conducted on how the product can be modified in order to be able to mass produce it using the simplest possible procedure.
The KUKA jointed-arm robot has a clear advantage over a gantry unit in that it enables different production processes to be tried out, without requiring expensive conversion measures. |
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