Enhancement of incremental forming process formability by using improved clamping and multi-stage deformation strategies

Single point incremental forming is a flexible sheet forming process that does not require a dedicated punch and die for making products for various applications. However, forming parts at steep wall angles, closer to 90 degrees, using this process poses difficulties due to excessive thinning. The motivation behind this study is to overcome the challenges associated with forming parts at steep wall angles using the single point incremental forming process. Controlling the thickness distribution is a significant challenge that needs to be addressed. Excessive thinning leads to disqualification of design criteria, thereby restricting the process' industrial applicability. In the present work, an improved clamping mechanism along with a multi-stage forming approach is employed to address the issue of excessive thinning. Two strategies were evolved; in strategy 1, an improved clamping mechanism was developed for single stage single point incremental forming, while strategy 2 consists of the improved clamping strategy along with a multi-stage forming approach for a single point incremental forming process. The improved clamping was based on the deep drawing process' blank holding type clamping mechanism in both these strategies. The study aimed to compare the formed components' forming depth and thickness distribution using the two strategies. The result revealed that strategy 2 was more effective, resulting in better thickness distribution in the formed component. The thickness distribution improvement resulted from metal flow from the flange region, owing to the improved clamping strategy, during the single and multi-stage forming at steep wall angles.