Tape a piece of paper on the front of the KitchenAid dishwasher's door. Write the current date and time, like: "Monday -- MM-DD-YYYY -- 9 p.m." After starting a cycle, record a description about the load that you put into the dishwasher: "Washed dishes after dinner on the 'Normal' setting." Also note the intensity of the buzzing: "The entire kitchen counter buzzed to the point of vibrating utensils."
Run the dishwasher for a second and third cycle. This can be done on the same day, such as after breakfast and dinner, or on different days. The important thing is to run the machine for three cycles to give the grinder separate opportunities to handle especially tough foods. Make a complete record of each cycle.
Run the dishwasher for a fourth cycle, also recording this event. However, periodically listen to the dishwasher as it goes into the actual cleaning phase. Most KitchenAid dishwashers have control panels that illuminate the various phrases, including the "Wash" cycle. If the buzzing noise no longer exists, that means the dishwasher has successfully and completely ground down hard food items into tiny particles that have since washed away through the drain.
Contact a service technician if the buzzing and grinding noises persist.