Comparison of Advanced SPF Die Technologies in the Forming of a Production Panel

Abstract

Superplastic forming (SPF) is a manufacturing process that can facilitate increased use of aluminum in automobile body structures. Despite considerable advantages with regards to formability and tooling costs, the process has been mostly limited to low volume production due to relatively long cycle times and the need to use specially processed sheet alloys. To address these issues, advanced processes such as two stage gas forming (TSGF) and hot draw mechanical pre-forming (HDMP) have been developed. Advantages of these processes have been demonstrated on the forming of a complex dash panel part. Final thickness distribution and forming time on this part manufactured with these two processes were compared to that of the same panel produced with conventional SPF. The HDMP technology which combines hot stamping with SPF was found to have the capability of forming a complex shaped component with a superior thickness profile and faster forming cycle than that formed with a conventional single stage or two stage forming cycle. Additionally, the HDMP process proved to be a robust process with a wide temperature window and allowed for the forming of lower-cost, non-spf aluminum, and magnesium sheet alloys. Finally, analysis of the post-form microstructure indicated that there was essentially no cavitation in panels formed with the HDMP process and that material with a coarse grain structure could be successfully formed.

Effects of flow stress behaviour, pressure loading path and temperature variation on high-pressure pneumatic forming of Ti-3Al-2.5V tubes

“…Based on the two-stage SPF process, Luckey Jr. et al designed a preform die to improve the thickness profile of SPF5083 alloy parts [8]. Luo et al also compared two-stage gas forming (TSGF) and hot draw mechanical preforming (HDMP) to conventional SPF when forming a SPF5083 alloy part and found that HDMP could provide a superior thickness profile and faster forming cycle than the other two processes [9]. Liu et al combined deep drawing and blow forming into one operation.…”

High-temperature lubricants for superplastic forming of metals

“…[2][3][4][5] This approach can reduce cycle time, thereby increasing possible production volumes. The simplest embodiment of this approach is either a plug-assist die or simply a die with a non-planar binder.…”

Finite Element Modeling of a Non-Isothermal Superplastic-Like Forming Process

“…It has some advantages, such as forming large and complex work pieces, excellent precision and fine surface finish, and little springback or residual stress in the formed parts [2][3][4][5]. Conventional superplastic forming has been modified to increase the productivity and reduce some of the drawbacks, such as high percentage thinning to suit the automotive industries [6]. One of the modifications is to combine between the conventional SPF and the use of a non-superplastic AA5083 sheet [7].…”

“…The study of superplastic forming process mainly contains the material selection [8], processing technique [6], and finite element modeling (FEM) [9]. FEM is a numerical method normally used to facilitate the SPF process design [10].…”