The most time consuming job in the sheet metal forming process is compensating for springback. Factors such as uneven material properties and process conditions generate noise, which in turn create springback. The springback is very sensitive to the process and noise conditions, and the main effects of the design variables cannot be obtained from mean analysis. Therefore, to achieve minimal springback, an effective design countermeasure must be put in place to reduce noise effects. In this study, two robust design methods to achieve minimal springback in U-channel forming, including compensation process, are proposed. The effectiveness of the proposed methods is shown with an example of the sidewall curl springback. The proposed methods consistently outperform our previous work, indicating that the complex method is more preferable to the mean analysis, if there is no evidence of additivity of effects.