Simple Solutions That Work! Issue 16

FLEXIBLE MANUFACTURING & ENGINEERING TRENDS 33 were required to achieve the optimum result. Total computer time was less than 2 hours. Figure 4 shows the progression of process yield during the simulations. The original riser design gave a process yield of 60%, and the final result was a process yield of over 72%. You can see that in some of the earlier runs there appears to be a better process yield than the final result. These runs violated the constraints for the run in that there was shrinkage detected in the casting. Final shrinkage predication for the optimized risering is shown in Figure 5. You can see that the riser is used much more effectively than the original configuration. The riser size reduction was 6.64 lbs. Since each mold had 8 impressions, the total weight savings per mold was 53.1 lbs. Since this was a high production situation, this resulted in a melt savings of over 1800 tons of metal per year. The annual energy savings was 1,980,000 KWH and the annual cost savings was over $100,000. Figure 2. Shrinkage Predication for Original Risering Figure 3. Riser Height and Diameter were selected as optimization variables Figure 4. Progression of Yield Improvement during the optimization run. Figure 5. Shrinkage Prediction in the Optimized Riser Configuration. Contact: DAVID C. SCHMIDT dave@finitesolutions.com