Ignis ADL 394 S dishwasher?

My dishwasher is making what can only be described as a grinding noise when washing. Initially, I thought it was because the twin plastic pipes, which come in through the base of the machine and feed the washing spray jets, were loose and kept coming displaced during the wash cycle. Eventually I stuck the pipes in place with an epoxy resin. This seemed to do the trick as my glasses and dishes were cleaner and the noise seemed to subside.

Today the noise has started again. The pipes appear to be fast in their places so I am now at a loss as to what is making this noise.

Can you help please?