Integrated yield was estimated to be valued at approximately $20,000,000 per percentage point.
Yield loss is a major issue in the steel industry as it is in most industries. The steel supplier in this case had purchased and was planning on installing a slab scarfer. The firm utilized various scarfing practices depending on temperature and slab width. These different practices influenced product quality and yield loss. The yield loss was running at about 4% and product defectives attributable to slivers were at 10%. Integrated yield was estimated to be valued at approximately $20,000,000 per percentage point.
Approach
A Luftig & Warren methodology referred to as Statistical Startup was employed for this situation. This technique utilizes AQP, QFD and other powerful statistically-based tools to achieve a smooth startup, on time and under budget whether the item is a purchased piece of equipment, an installation of a line or the building of a facility. In addition, the outcome of the methodology is to provide for less variability in the final product characteristics, on target and with reduced or no product defects together with better equipment reliability (i.e., MTBF, MTTF).
ResultsThe study explained more than 90% of the variability in yield loss. After successful installation, overall yield improved 50% (from 2% to 4%) and product defects attributable to slivers was reduced by nearly 70%. The installation was completed ahead of schedule and under budget.
Submitted by
LWI Consultant
Bob Pahlkotter