Kaleem, Muhammad Ali
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Publication Access status: Metadata only , Additive manufacturing of polymeric pressure die for rotary draw bending process3D printing or additive manufacturing (AM) possesses enormous potential to benefit the manufacturing industry. Presently, rotary draw bending (RDB) is one of the most commonly used cold-forming industrial process for bending metal tubes. Pressure die is a fundamental forming tool in RDB processes, and it is conventionally made by various grades of comparatively expensive alloy steels. This research presents a novel design of a pressure die which can be 3D printed by using inexpensive polymeric filaments. In this research paper, the 3D-printed pressure die is named as “FFF-pressure die.” The material used to fabricate the FFF-pressure die is a thermoplastic polymer known as “ecoPLA.” The mechanical properties of ecoPLA are studied in relation to the process conditions of a RDB process. Firstly, an initial feasibility of using the FFF-pressure die in a RDB process is obtained by conducting a quick static stress analysis with actual process conditions. After initial feasibility, a complete RDB process is developed and simulated with actual process conditions and material properties. The FFF-pressure die is then practically fabricated by FFF 3D printer and experimentally tested on an industrial RDB machine. The results of practical experiments are compared with the simulation results. In order to make a comparison of the FFF-pressure die with the conventional metal pressure die, the simulation and practical process is also conducted with the conventional metal pressure die. A performance and cost comparison is made between the polymeric FFF-pressure die and the conventional metal pressure die. Von Mises stresses, contact forces, failure risk, and elastic deformations are analyzed. The advantages and limitations of using the FFF-pressure die in a RDB process are discussed in the end. This research intends to widen the avenue of using cost-effective and lightweight forming tools in metal forming industries.Source Type:Article5 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Design and Development of Hybrid Tools for Rotary Draw Bending Using Digital Twin and Additive Manufacturing Processes(2026)Rotary draw bending (RDB) process is a profile bending process mostly used in industrial practices for bending metal tubes. Presently, RDB process is conducted by using geometry specific bending tools. The fundamental tools used in RDB process are pressure-die, bend-die, clamp-dies, wiper-die, collet and mandrel. These tools have simplified geometries with a semi-circular tool surface which corresponds to only one specific tube diameter. This makes RDB process inflexible because different tube diameters cannot be used with a specific set of bending tools. In addition to process-flexibility, the modern production regime of present era needs bending tools to be cost effective and light weight. This doctoral thesis is aimed to utilize modern manufacturing techniques, i.e., 3D printing processes and digital twin of RDB process, to develop the geometric design of bending tools which should be cost effective, light weight and provides process-flexibility to RDB process. A digital twin of the RDB process is developed and the accuracy of the digital twin is verified by comparing the FE-simulation results with practically conducted experiments. The design factors which critically influence the tool design are identified through digital twin prototyping. The digital twin prototyping method encompasses systematic development and testing of 3D printed polymeric tools in RDB process. Topology optimization of a conventional tool geometry is conducted in order to identify minimum material required within the tool. The results obtained from digital twin prototyping and topology optimization envisioned the development of a hybrid tool. A hybrid tool consists of two different materials i.e., polymers and metals. The materials of a hybrid tool are selected from Ashby material charts on the basis of requirements resulting from process parameterization and topology optimization. A model of the hybrid tool is developed according to material properties of selected materials and identified tool design factors. The model is imported in digital twin of RDB process and tool performance is investigated by conducting process simulations with different tube diameters. After obtaining process feasibility through digital twin, the hybrid tool consisting of polymer - PLA and metal - stainless steel is practically 3D printed and experimentally tested in an actual RDB process. The experimental results demonstrates that a 3D printed hybrid tool is capable of conducting bending operations with different tube diameters while enabling significant material saving within the tool. A comparison is made between the novel 3D printed hybrid tools and conventional steel tools. A design formula is presented that determines the efficiency of bending tools through Tool Efficiency index (TEi). For practical applications, the geometry of 3D printed hybrid tools is standardized through aspect ratio and corresponding upscale size factors.Source Type:Doctoral ThesisSeries:Forschungsberichte des Lehrstuhls für UmformtechnikVolume number:2028 49 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Metadata only , Surface roughness and coefficients of friction of 3D-printed clamp tools made from selective laser meltingThe practical use of 3D-printed metal tools in production industries requires accurate characterization of tool behaviour. In metal forming industries, the efficacy of clamp tools largely depends on surface roughness and friction behaviour of tool surfaces. This research is aimed to investigate surface roughness and friction behaviour of 3D-printed clamp tools made from selective laser melting process. Gas atomized powdered tool steel-X3NiCoTi1895 (EN 1.2709) is used to 3D print clamp tools. A mechanical setup determines the friction coefficients of 3D-printed samples under practical loading conditions. The effect of raster angle on surface roughness of 3D-printed clamp tools is determined. These findings serve as the basis of a broader project in which metal-3D-printed forming tools are developed and tested in actual production setups.Source Type:Article4 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , The way forward in rotary draw bending: a reviewPresently, Rotary Draw Bending (RDB) process is one of the most common tube bending techniques used in industrial production around the world. The process is executed on a specially designed machine being fitted with specific forming tools. The quality of final products in RDB largely depends on process parameters being selected by the machine operator. These process parameters are selective balance of movements and effect of forming tools on the tubes. Substantial development has been done in identification of optimum process parameters for improving the quality of bent tubes. Each process parameter has a unique and versatile effect on quality aspects like ovality, wrinkling and fracture of the tubes. This reviewbased research is focused on gathering published information on so-far identified process parameters in RDB and their eventual effect on the tube’s quality. In the end, authors present their own perspective about the future of a RDB process. The authors perspective suggests merging of AM (Additive Manufacturing) with conventional RDB process to impart enhanced efficiency and improved quality to forming tools and bent products respectively. Apropos, a concept of hybrid pressure die is presented which encompasses manufacturing of a fundamental forming tool (pressure die) using AM techniques. The suggested model of hybrid forming tools opens a new avenue for industrialists to manufacture more flexible, cost effective and substantially beneficial tools for the RDB process in future.Source Type:InProceedings295 317 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Topology optimization of die geometry through identification of high pressure areas on die surface(2025); ; In profile bending of tubes, FE-simulations have shown that the contact between tool (die) and metal tube manifests a unique contact pressure pattern at the tool surface. In this study, practical sensors are employed to determine the pressure transmission from tube onto tool surface. The physical measurements provided by sensors showed high agreement with the FE-simulation. It is demonstrated that the pressure exerted by the tube is not transmitted uniformly throughout the tool surface rather it is localized towards centre and fringes. This investigation opens up the possibility to design tools (forming dies) using topology optimization. The topology optimized geometry of a tool results in substantial material savings within the tool geometry. This research paper demonstrates that the identification of pressure pattern on the tool surface provides the basis to design tools with bare essential material within the tool geometry, hence stepping forward towards cost effective manufacturing of tools.Source Type:Article8 31 - Some of the metrics are blocked by yourconsent settings
Publication Access status: Open Access , Transformation in der BiegetechnikMit dem 6. Biegeforum hat der Lehrstuhl für Umformtechnik an der Universität Siegen ein neues Format geschaffen, in dem neben der Industrie nun auch den Forschenden ein eigener Schwerpunkt am Forum gegeben wird. Im vorliegenden Tagungsband sind Fachvorträge zum aktuellen Stand der Forschung sowie von Innovationen in der Umformtechnik zusammengefasst. Sie geben einen spannenden Einblick in hochaktuelle Forschungsergebnisse zum Biegen. Seit seiner erstmaligen Auflage im Jahr 2011 hat sich das Biegeforum zu dem etablierten Treffpunkt für Wissenschaft und Praxis entwickelt. Es findet fortan im zweijährigen Rhythmus statt.Source Type:Conference ProceedingsSeries:Forschungsberichte des Lehrstuhls für Umformtechnik696 317