An extensive retrofit – including new gantries and servo grippers – was completed in the final finishing area robotic buffer system for PCR tires in early 2013. Leading a team of 60 people, Dietmar Jobes is Maintenance Manager at Continental’s Aachen factory, responsible for ensuring the availability of all the production and handling systems in his section. Here, he answers some questions about the project.
Why was this retrofit project undertaken and what did you want to achieve?
We had a dramatic decrease in the availibility for this system; it was at an unsatisfactory level. In addition, the maintenance costs had increased. In short, it was causing production losses. The system had endured intensive use and high volumes for five years – amounting to 50,000 working hours over 3 shifts – running at its utmost limit. According to the component life expectancies from Cimcorp, the usage hours of the wearing parts had been exceeded and many of the longer-life components were nearing the end of their lifecycle. We investigated the causes of the wear in great detail and found that, as the six-robot system was located in limited space within our rather crowded site, the driving distances of the robot axes were very short. The robots were actually accelerating and decelerating for 90% of their operational time. They were therefore running at a steady speed for only 10% of the time. This rapid ’stop/go’ operation caused oscillation and vibration, which in turn led to high wear of components, excessive play in the system, inaccurate positioning and material fatigue. Not surprisingly, the result was continuous failures.
How did you arrive at a solution?
We sat down with Cimcorp’s customer support experts and discussed the problems very openly. Cimcorp proposed three alternatives, each with a different scope of supply, starting from smaller changes to a complete retrofit. Continental decided to invest in the most extensive solution – a complete system retrofit, including new gantries – because this would secure the best results. In addition, the downtime involved was actually the shortest of the three options and the system would be modernized to a whole new level of technology, with significantly longer expected lifetime than for the alternative options.
What was involved in the retrofit?
The retrofit was implemented in just two weeks during the Christmas shutdown in 2012-2013. The robot units – both the overhead gantries and the grippers – were replaced. The new gantries are lighter and yet more robust, while the servo grippers are faster. The rack and pinion drives were replaced by belt drives and software changes were also implemented to make the robots’ move-ments smoother.
What have the results of the retrofit been?
The availability of the buffer system has increased significantly, now reaching 99.5%. Most of the time we work without any failures, 24 hours a day – that’s a great result! At the same time, maintenance costs have been reduced dramatically – to half or even less than half of the previous costs.
How would you rate Cimcorp’s performance in terms of technical solutions, project management and customer support?
Cimcorp’s solutions feature the highest level of technology – the robots really are state-of-the-art. In this retrofit project, Cimcorp developed the various solutions, made detailed proposals and quotations, and then implemented the job as they had planned and promised. It was highly professional, with no time delays or crisis points during the project – an excellent job! As for customer support, Cimcorp is always available. We have absolute trust in that.
TEXT: PAULA OVASKAINEN & HEIDI SCOTT PHOTOS: ARTO HELIN
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