What was the problem?
The screw broke!
After approximate 1 year of operation, a 150 mm diameter screw broke. However, unlike a “cold start” break, which typically occurs in the feed section where the screw root diameter is the smallest, this break occurred near the end of the barrier section, where the screw root was essentially the largest, and presumably, the strongest. Believing that the failure was a result of poor steel quality, an identical second screw was manufactured and it experienced the same failure in the same amount of production time.
Simulation of the original design, prior to manufacturing the screw, could have shown the problems with melting allowing the design to be corrected and optimized. This would have saved the cost of the premature screw failure (including the cost of the second failure). It would also save the associated loss of production and extend the life of the barrel which had pre-maturely worn as a result of the poor screw design.