June 2021

16 | Plant & Works Engineering www.pwemag.co.uk June 2021 Maintenance Matters Focus on: Condition Monitoring W ith robots playing a vital role in a multitude of production processes in automotive manufacturing, from body in white and assembly through to the paint shop, it is vital to ensure that everyone deployed on a production floor is kept operating at peak condition in order to prevent disruption caused by an unexpected failure. There are many factors that can affect the performance of a robot on the factory floor. One is age. The long lifespan of industrial robots means that some of the units being used on automotive production lines are getting older. Understandably, manufacturers would like to extend their lifetime rather than replace large numbers of robots. Having clocked up thousands of operating hours, some of these will undoubtedly require more frequent maintenance to keep them in good running order. Another factor is the need to avoid long MTTR (Mean Time Til Repair) periods – if the spare part is not on site, delays can be incurred while the part is ordered and delivered. The need to cover ’what if’ scenarios can also make it difficult to know how many spare parts to purchase, which can result in excessive spares holding, tying up capital and requires extra storage space that could be put to more productive use. A third factor is the way robots are programmed and used. Factors such as incorrect usage, wrongly defined loads, high energy collisions, oil contamination or late oil change can all contribute to reducing the lifetime of the gearbox and an increased risk of premature failure. Until now, predicting wear and tear on robots and their component parts has not been an easy process, especially in applications where several hundred may be deployed. In the same way that some human workers work harder than others, handling heavier tasks or operating more quickly, so the same is true of robots. Robots are not all subject to the same stresses and wear, even robots of the same type on the same production line. The differences are down to the robot program, which sets the motion cycles and dynamics for each axis. These can differ greatly depending The need to keep automotive production lines running at their optimum performance requires that the machinery and equipment used in those lines should be doing the same. In this article, we look at how condition-based maintenance can help make sure that those robots most in need of attention on a factory floor receive the care they need to keep them in good working order. PWE reports. Keeping car plant robots working