Flexible tooling for impulse forming

Langstädtler, Lasse; Pegel, Holger; Beckschwarte, Björn; Herrmann, Marius; Schenck, Christian; Kuhfuß, Bernd

doi:10.1016/j.promfg.2018.12.055

Cited by 7 publications

(5 citation statements)

References 19 publications

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“…To accelerate the product development a wide range of previous work was focusing on faster tool provision, which spread from modular [1] and reconfigurable [2,3] tools to completely new approaches of tool production [4] like stereolithography processes [5]. Langstädtler et al showed that the combination of impulse forming and flexible tooling offers three different fields of flexibility for a rapid manufacturing, which are categorized into the aspects of die material, tool provision and process design [6]. The idea of rapid tooling for forming, embossing and cutting processes arose with a strategy that combines impulse forming processes like electromagnetic forming (EMF) or electrohydraulic forming (EHF) -where the die is loaded and unloaded very quickly by an adaptable force action that replaces the punch -with unconventional die materials and new tooling concepts.…”

Section: /1mentioning

confidence: 99%

Rapid Tooling for Impulse Forming

Langstädtler¹,

Intemann²,

Herrmann³

et al. 2021

Esaform 2021

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Compared to cutting processes such as milling, forming processes like electrohydraulic forming offer advantages regarding resource as well as energy efficiency. Due to high tooling costs, forming technologies are nonetheless considered as economically inefficient for low production quantities. Using a combination of high-speed forming with 3D printing technologies for tool manufacturing, three variants to reduce tooling time and costs for processing sheet metals for small quantities were proposed. Since the dies have to withstand high dynamic loads, 3D-printed low-cost dies made of polylactide (PLA) are limited regarding their form stability, mainly depending on the forming energy and sheet thickness. To enlarge the scope of application for 3D-printed dies a method to reinforce these dies is presented and investigated. Armoring of the dies was achieved by electrohydraulic cladding of the dies with 0.5 mm thick aluminum sheet metals. To characterize and compare the properties of the unarmored and the armored polylactide dies, specific characteristics of the formed sheet metals concerning the die wear and the molding quality were investigated. Polylactide dies enabled embossing of fine structures in addition to the forming of the die shape. Armoring of the dies led to a reduction of the embossed layer structure. Therefore, the armoring can be used as a way to control the characteristics of the formed sheet metals. In a further step, the cladding sheets were produced with copper sheet metals and used as sinking electrode for electric discharge machining of steel dies.

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Section: /1mentioning

confidence: 99%

Rapid Tooling for Impulse Forming

Langstädtler¹,

Intemann²,

Herrmann³

et al. 2021

Esaform 2021

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“…Besides forming [3] it is also applied for operations like cutting [4], joining [5] and embossing [6]. Further advantages which bring this process in the focus of investigations are a one-sided die [7], high strain rates [8] with following changes in plastic material properties of the workpiece [9]. Furthermore, the workpiece behavior exhibits less wrinkling [10] and springback [11] due to this forming process.…”

Section: Intr Introduction Oductionmentioning

confidence: 99%

Electromagnetic Embossing of Optical Microstructures with High Aspect Ratios in Thin Aluminum Sheets

Heidhoff¹,

Beckschwarte²,

Riemer³

et al. 2021

Esaform 2021

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Electromagnetic embossing enables the transfer of surface structures from forming dies to metal sheets at high forming speeds. For this purpose, the contactless forming force is provided by means of a magnetic field of a tool coil which interacts with an eddy current in the workpiece. In thin sheets which are completely penetrated by the magnetic field, the resulting Lorentz forces act as body forces that accelerate the workpiece onto the forming die. In addition to the body forces, also high strain rates can support the embossing of thin sheets. This investigation deals with the embossing of pyramidal structures in the submillimeter range and an aspect ratio of about 1 into thin aluminum sheets (3.0255 / Al99,5). In order to quantify the reproduced microstructures, their extent is determined by means of a lateral analysis. From this, the replicated height is derived. Up to now it has been possible to partially reproduce microstructures with a large aspect ratio in thin sheets. In addition, the changing surface roughness of the sheets is taken into account. Before embossing, the sheets exhibit a relatively rough surface with a rolled texture, which is smoothed by the impulse forming with an optical forming die. This study reveals basic approaches for the electromagnetic embossing of optical microstructures.

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“…These forming channels were designed to have a high aspect ratio of channel length to channel diameter as well as channel length to sample length. As the manufacturing of channels with changing diameters is challenging, assembling them from forming channel stages was investigated [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

Short-Term Material Characterization by Electrohydraulic Incremental Extrusion through Micro Channels

et al. 2021

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Conventional testing procedures for characterizing the mechanical behavior of materials require intense preparation in geometry and in the handling of the samples to apply specific stress conditions. Furthermore, these procedures are time consuming. In a novel method for high-throughput development of new material, spherical and cylindrical micro samples should also be tested within a short time. For mechanical testing, the samples need to be exposed to specific types of stress. As most conventional testing procedures are not applicable, new testing procedures are demanded. The incremental electrohydraulic extrusion of micro samples through micro channels is a new testing procedure that was introduced for short-term material characterization. Loading energy is used to cause shock waves that incrementally push the samples through the forming die. The resulting deformation progress is measured between the forming steps. In this research, process simulations are used for channel design and material flow analysis. The designed channels that cause specific stress in samples are realized by stacking elements radially or axially. The stacking enables sample access for measurement and unloading and ensures good machinability of the forming channels. New testing cases for short-term characterization of cylindrical as well as spherical micro samples by electrohydraulic extrusion are presented according to monotone tensile, compression, and torsion testing. Furthermore, production-related testing and cyclic load testing are introduced by incremental electrohydraulic extrusion. By measuring the deformation due to the dependence on supplied energy, flow curve equivalents are determined that correspond to values from conventional material testing procedures.

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Flexible tooling for impulse forming

Cited by 7 publications

References 19 publications

Rapid Tooling for Impulse Forming

Rapid Tooling for Impulse Forming

Electromagnetic Embossing of Optical Microstructures with High Aspect Ratios in Thin Aluminum Sheets

Short-Term Material Characterization by Electrohydraulic Incremental Extrusion through Micro Channels

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