3D printed prototyping tools for flexible sheet metal drawing

Abstract

Due to the change from mass production to mass personalized production and the resulting intrinsic product flexibility, the automotive industry, among others, is looking for cost-efficient and resource-saving production methods to combining global just-in-time production. In addition to geometric manufacturing flexibility, additive manufacturing offers a resource-saving application for rapid prototyping and small series in predevelopment. In this study, the FDM process is utilized to manufacture the tooling to draw a small series of sheet metal parts in combination with the rubber pad forming process. Therefore, a variety of common AM polymer materials (PETG, PLA, and ABS) is compared in compression tests, from which PLA is selected to be applied as sheet metal forming die. For the rubber pad forming process, relevant processing parameters, i.e., press force and rubber cushion hardness, are studied with respect to forming depth. The product batch is examined by optical evaluation using a metrological system. The scans of the tool and sheet metal parts confirm the mechanical integrity of the additively manufactured die from polymer and thus the suitability of this approach for small series in sheet metal drawing processes, e.g., for automotive applications.

Sustainable tool technology: Wood-based forming tools

“…The aim of the present study is the investigation of a potential substitution of conventional tooling materials for sheet metal forming applications through biologicalization. For comparison, similar process boundaries were applied as in the preceding studies [8,9], where the mechanical stability of fused deposition modeling (FDM) printed dies from polylactic acid (PLA) with solid and reduced infill was investigated in forming DC03 (0.7 mm) sheet metal parts in a rubber pad forming process featuring a polyurethane pad (shore hardness 40). Based on the previous work, the load collective of the drawing process was adopted for composite layered tools of BL.…”

“…AM offers the opportunity to adapt optimized structures and to manufacture them precise without surplus material [20]. In manufacturing, AM was successfully implemented as tooling material e.g., sheet metal forming [8,9,21,22]. Along AM, biologicalization is a suitable mechanism to adapt nature based optimization and material range to sustainable manufacturing systems [2].…”

“…Based on previous characterization and numerical analysis as well previous investigations from [8,9], two composite structures were rectangular aligned out of 3mm black locust sheets glued together with polyurethane (see Fig. 5), according to [23].…”

Compressive Behaviour of 3D-Printed PETG Composites

“…A similar behaviour was observed for PETG but for lower compressive values (2-3 times smaller). Sörensen et al [15] used the FFF process to manufacture a tooling to obtain a small series of sheet metal parts in combination with the rubber pad forming process for the automotive sector and, for this purpose, a variety of common AM polymeric materials (PETG, PLA and ABS) were compared in compression tests. Both PETG and PLA were able to fulfil the proposed performance (loading capacity), but in this study, PLA was selected due to its bio-based structure and its industrial composting possibilities.…”

“…Therefore, from the literature [2][3][4][5][6][7], it is evident that PETG and PETG-based composites have applications in many industries due to their resistance to heat, impact and solvents. In terms of compressive properties, the focus of the present study, the literature is not abundant on this topic and what exists is not enough to establish a consolidated knowledge base [13][14][15][16][17], because most of the available studies focus essentially on the tensile mode. On the other hand, as consequence of the inherent viscoelasticity of the matrix phase, polymer composites are prone to creep and stress relaxation, making it a great challenge when used in long-term applications.…”