Process window approach measures how well a manufacturing process fits into a higher capability level of the process limit known as the specification limit. the specification limit is the tolerance allowed for the process obtained in the production in terms of cpk and is statistically determined. in the sand casting foundry, these specification limits are known as the process window, and values that a plotted inside this window is known as the process window approach. using pwa values, casting process performance can be accurately measured, analyzed, compared. for an analogue-style of specification (cpk), the lowest defects could exist at some value or sweet spot within the range but not at its centre. if such data available for a specific product, then the process parameter set up should be adjusted to move the mean closer to this sweet spot to produce less defects. once the analysis prediction can be relied upon, the pwa must efficiently find the optimal parameter set up. it should validate the entire range of all parameters and all possible combinations. in this work, an innovative approach to validate the sand casting process optimization analysis. optimal solution arrived from the taguchi analysis and rsm, the set of parameters are again analyzed to its significance on the defects. based on percent contribution, it is identified and the four significant parameters are analyzed in the response surface methodology. the pwa is a powerful tool for quickly validating the performance measurement thereby robustness of the process parameter setup of rsm. in this approach the most significant parameters moisture content, permeability, volatile content and mold pressure is selected and other parameters are kept as it is. these parameters are more critical to the overall process or more likely to cause defects. pwa considering all interaction parameters separately and gives the optimal result for the individual parameter by selecting sweet spot through process window.pwa is a totally different concept in the form of mathematical matrix as in taguchi orthogonal array and rsm design coding. it is also a reversible action to validate and optimize the process where the personnel approaching the tool with respective of use. taguchi and rsm the values selection is based on “smaller is better” concepts, relates to casting defect. but in pwa the greater cpk value determines the better parameter level at casting defects are less.for some parameters, the minimum or maximum are true, binary statistical specification limits where any value inside the range is good and any value outside the range is a defect. the overall cpk value provides an excellent metric for qualitatively evaluating processing parameter adjustments. if relationship between cpk and quality (defects) is clearly understood, an acceptable maximum cpk value can be established for pwa. if a modeling algorithm is available for the process, then changes can be evaluated without actual physical experiments and the ultimate method for optimizing a process setup using search engine. the search engine would change all of the setup variables, using the model’s algorithms to calculate the pwa for each combination. obviously, two fundamental requirements are needed for such a system to be successful. first, the model must be accurate for the full usable range of all setup parameters. second it should be able to self-correct based on confirmation test data versus results predicted by its algorithms once the model predictions can be relied upon, the search engine must efficiently find the optimum process setup. it should evaluate the entire range of all parameters and all combinations in a reasonable time. for example, overnight computing is acceptable to optimize the casting process. if certain parameters are more critical to the overall process or more likely to cause defects, their priorities can be increased by tightening the limit values for the pwa calculations inside the actual specification limits.