Yield of modified component:

� � volume of part ¼ mass=density <sup>¼</sup> <sup>3</sup> <sup>58</sup>:<sup>5</sup> kg=<sup>7800</sup> kg=<sup>m</sup> <sup>¼</sup> <sup>8</sup>:<sup>4</sup> � <sup>10</sup>�<sup>3</sup> <sup>m</sup><sup>3</sup> <sup>Q</sup> volume of riser <sup>¼</sup> <sup>D</sup><sup>2</sup> =4 � H <sup>¼</sup> <sup>1</sup>:<sup>45</sup> � <sup>10</sup>�<sup>3</sup> volume of gating system ¼ volume of basin þ volume of sprue þvolume of runner þ volume of gates <sup>¼</sup> <sup>1</sup>:<sup>98</sup> � <sup>10</sup>�<sup>3</sup> yield ¼ volume of part=ðvolume of part þ volume of runner þvolume of gating systemÞ <sup>¼</sup> <sup>8</sup>:<sup>4</sup> � <sup>10</sup>�<sup>3</sup> <sup>=</sup> <sup>8</sup>:<sup>4</sup> � <sup>10</sup>�<sup>3</sup> <sup>þ</sup> <sup>1</sup>:<sup>45</sup> � <sup>10</sup>�<sup>3</sup> <sup>þ</sup> <sup>1</sup>:<sup>98</sup> � <sup>10</sup>�<sup>3</sup> <sup>¼</sup> <sup>71</sup>:4% Here, yield is decreased by 4.7%.

#### 10. Conclusion

Preliminary defect analysis shows that, compared to other products, Crank Case 3000 has the highest rejection rate of 15.4%. A bar chart shows that, compared to the other defects, core shift and sand drop were observed to be most common. This fact is proved by the Pareto analysis that shows that core shift and sand drop are the cause of more than 80% of the rejections. Many factors affect core shift and sand drop. To find out which of the factors was contributing the most, a cause effect diagram and Why Why analysis was performed. From the cause effect diagram, a weighted average table was created to find out the key causes of the defects, where the causes with the highest weighted average were taken into consideration, which includes sand parameters like GCS, permeability, moisture and compactibility. From the Why Why analysis, it was observed that out of all the root causes available, the controllable factors were the sand parameters of molding sand while the rest of the factors are not controllable. So these factors were selected for further analysis. After carrying out experiments (DOE) on sand parameters (GCS, permeability, compactibility and moisture) and the rejection rates, it was found that a 3% change in permeability results in a 20–25% change in the rejection rate. Thus optimum changes in permeability are required to control rejection rate. Application of new sand parameters and design gives sound casting but a compromise in yield of 4.7% is acquired.

Proceedings of the 4th International Conference on Innovations in Automation...
