SEM-Invaluable and practical tool for casting defect analysis before a DOE

摘要

The initial results from the DOE clearly indicated that even before the statistical analysis was performed, the defects had not been accurately identified. However, due to the fact that proper scrap analysis was conducted, it became obvious that, to solve the actual scrap problems, at least two independent designs of experiments would be needed: one to solve the broken core problem and one to solve the oxides or inclusion defects. In summary:The use of design of experiments is a team effort.Every team member recognized the importance to properly diagnose a defect before any corrective action takes place.Even educated assumptions are not as good as actual microscopic evaluation.Metallurgical defects in location "A" were due to dry sand core stickers.Metallurgical defects in location "B" and "C" were due to green sand inclusions.Metallurgical defects in location "D" were due to meld turbulence.Finally, it is important to mention that, based on these findings, corrective actions were implemented, and new designs of experiments were conducted according to new selected factors.