Computer Aided Modelling of Rubber Pad Forming Process

Abstract

Rubber pad forming (RPF) is a novel method for sheet metal forming that has been increasingly used for: automotive, energy, electronic and aeronautic applications [1]. Compared with the conventional forming processes, this method only requires one rigid die, according to the shape of the part, and the other tool is replaced by a rubber pad [1]. This method can greatly improve the formability of the blank because the contact surface between the rigid die and the rubber pad is flexible. By this way the rubber pad forming enables the production of sheet metal parts with complex contours and bends. Furthermore, the rubber pad forming process is characterized by a low cost of the die because only one rigid die is required [2]. The conventional way to develop rubber pad forming processes of metallic components requires a burdensome trial-and-error process for setting-up the technology, whose success chiefly depends on operator’s skill and experience [4][5]. In the aeronautical field, where the parts are produced in small series, a too lengthy and costly development phase cannot be accepted. Moreover, the small number of components does not justify large investments in tooling. For these reasons, it is necessary that, during the conceptual design, possible technological troubles are preliminarily faced by means of numerical simulation [4],[6]. In this study, the rubber forming process of an aluminum alloy aeronautic component has been explored with numerical simulations and the significant parameters associated with this process have been investigated. Several effects, depending on: stamping strategy, component geometry and rubber pad characterization have been taken into account. The process analysis has been carried out thanks to an extensive use of a commercially finite element (FE) package useful for an appropriate set-up of the process model [7],[8]. These investigations have shown the effectiveness of simulations in process design and highlighted the critical parameters which require necessary adjustments before physical tests.

3D printed prototyping tools for flexible sheet metal drawing

“…The hardness is expected to show a compliant increase of the required forming force. Harder rubber pads generally require significantly higher press force but are sufficient to suppress the formation of wrinkles [11,30,31].…”

Design of the Production Technology of a Bent Component

“…Compared to conventional forming processes, the use of a flexible tool with polyurethane [20][21][22]39] requires only one fixed die according to the shape of the part and the second tool is replaced by a rubber pad. A holder of solid or laminated rubber pads should be made.…”

Design of Deformable Tools for Sheet Metal Forming

“…As another cost saving option, one or more of the metal tools are replaced with a rubber membrane. The Guerin process makes use of a movable thick rubber pad pressed against a die [2][3] or punch [4][5]. The Marform process is a variant of the Guerin, using an active blankholder [6].…”