Investigation of the hammer mill failure

In 1999 one Australian Company (the client asked not to disclose his name), experienced problems with hammer mils used to crush grain. Hammer mill strength was not satisfactory creating a danger of hammers breaking away. The Anticipatory Failure Analysis (Ideation/TRIZ methodology) was used to resolve the problem. It has been shown that the root cause of the problem was improper design and assembly procedure of the hammer mill, which made it out of balance causing severe vibration and hammer wobbling. As a consequence bearing stresses were replaced with contact loading causing extensive wear and the danger of hammers breaking away. Remedial measures were suggested to fight the problem.