Session: Research Posters

Paper Number: 113988

113988 - Applying Heat Shrinking to Minimize Pillow Effect During Incremental Sheet Forming 

Incremental sheet forming (ISF) is a dieless sheet-forming process that forms the desired final shape by incrementally deforming portions of sheet metal. One of the well-known quality problems with the ISF process is the pillow effect. The pillow effect refers to the undesired deformation of the unformed flat part of the sheet under the compressive residual stresses arising from the surrounding formed parts of the sheet which causes the bumping or buckling of the unformed flat surfaces. While the pillow effect is unavoidable in the ISF process, the formed pillow can be flattened by the shrinking of the material at the buckled area. Shrinkage can eliminate compression and provide a slight tension to regain the flatness of the surface. Among all different metal shrinking methods, heat shrinking has been used effectively by metal workers to shrink and flatten stretched areas on sheet metals. The method can be applied to different metals including steel and aluminum.

This project is an undergraduate ME capstone senior project involving four students and a Manufacturing Engineering Technology professor for technical support.  The goal of this research is to study the effectiveness of the heat-shrinking methods in reversing the pillow effect and increasing the geometrical accuracy of ISF formed products.  The value of the work towards the engineering education community lies in the integration of a variety of methods used by the students to study this innovative, real-world problem.  The student team had to become familiar with the operation of a FANUC R-2000ic 165F robot to create the ISF parts that heat shrinking would be applied to.  The team had to identify a suitable scanner to characterize the surface of the untreated and the heat treated parts to quanitfy improvements.  The team modeled the deformed original ISF part and created FEA models adding heat stress to numerically predict heat shrinking benefits.  The team investigated the analytical equations for the ISF part and created dimensionless parameters that helped guide their experimental investigation of ISF heat shrinking.

This project forced the senior team to locate real-world uses of heat shrinking, to educate themselves in the use of a robotic cell to make the ISF parts, guided by numerical simulations and analytical experimentall practices, the team investigated the ability of heat shrinking to minimize the undersirable phenomenon of the pillow effect.  Their work provides an example of a successful ME student capstone project and has the potential to guide future efforts to improve the ISF process.

Presenting Author: Kevin Schmaltz Western Kentucky University

Presenting Author Biography: Kevin Schmaltz has been at Western Kentucky University for twenty years, previously serving as the Chair of Mechanical Engineering at Lake Superior State University. Before entering the academic world, he was a project engineer for Shell Oil responsible for the design and installation of oil and gas production facilities for offshore platforms in the Gulf of Mexico. He has a combined 33 years of experience as an engineer in industry and in teaching. He teaches a variety of thermo-fluid and energy conversion courses, as well as design and professional component courses. He has coordinated the freshman, sophomore, junior, and senior project team-taught courses in the WKU ME program. He has presented a variety of conference papers on energy conversion initiatives and engineering design initiatives in education.

Authors:

Kevin Schmaltz Western Kentucky University