13th International Conference on the Technology of Plasticity (ICTP 2021): Novel Processes I
Program Organizers: Glenn Daehn, Ohio State University; Libby Culley, The Ohio State University; Anupam Vivek, Ohio State University; Jian Cao, Northwestern University; Brad Kinsey, University of New Hampshire; Erman Tekkaya, TU Dortmund; Yoshinori Yoshida, Gifu University
Tuesday 10:20 AM
July 27, 2021
Room: Virtual: Room E
Location: Virtual
Session Chair: Brad Kinsey, University of New Hampshire
Transcription of Mirror-finished Surface onto A5083 Aluminum Alloy Plate by Friction Stir Forming: Takahiro Ohashi1; Kento Okuda1; Hamed Mofidi Tabatabaei1; Tadashi Nishihara1; 1School of Science and Engineering, Kokushikan University
In this study, the surface smoothing effect was investigated with friction stir forming on JIS A5083 aluminum alloy plate with a mirror-finished nickel electroformed die. In the experiment, a material plate was placed on the die while friction stirring was conducted on its back surface. Furthermore, the high pressure and heat caused by the friction-stir process lead to material deformation, and the die surface profile was transferred to the material. The average of the arithmetical mean height (Ra) and maximum height of profile (Rz) of the material plate surface were improved from 2 and 17 micrometers to 1 and 9 micrometers, respectively. This improvement was achieved through a process that uses a die, whose surface roughness Ra and Rz were 1 and 8 micrometers, respectively. Moreover, the finished surface details were investigated, including its surface profile and microstructure, and discussion of the transcript mechanism by spectrum analysis using maximum entropy method (MEM) was presented.
Numerical Simulation of Pipe Bending Supported by Hydraulic Pressure for Manufacturing Butt-welding Fittings: Josef Domitner1; Peter Auer1; Christof Sommitsch1; 1Graz University of Technology
An innovative pipe bending process supported by hydrostatic pressure was patented in 1995. This process was designed for producing butt-welding fittings which particularly fulfil the dimensional specifications of the ASME B16.9, MSS SP-75 and MSS SP-43 standards. Since the patent has meanwhile expired, the bending process is now available for common use. This work presents a finite element (FE) model build in the software package LS-DYNA for determining the suitable process window to bend defect-free butt-welding fittings. The model was exemplarily applied for investigating bending of a 90° stainless steel elbow based on a straight pipe of nominal pipe size (NPS) 6. Comparing the calculated geometry of the elbow with the geometry of an industrially produced elbow revealed very good dimensional agreement. This confirms that the presented model can be utilized for determining suitable process conditions which allow for producing defect-free components.
Using Local Heat Treatment for Producing Uniform Profile Hollow Components by Radial Rotation Profile-forming: Robert Laue1; Sebastian Härtel1; Birgit Awiszus1; 1Chemnitz University of Technology
The two principal process steps of Radial Rotation Profile-Forming are the production of the preform and the subsequent radial profile forming of the hollow part. During the preform production wrinkles occur and these wrinkles can be formed directly in the indentation of the mandrel. In the second process step, the wrinkles are used to form the finish profile of the component. However, there is no wrinkle formed in every indentation. In this case, high sheet thinning and inhomogeneous properties occurs due to forming of the final profile. To avoid this disadvantage, a local laser heat treatment is carried out to control the wrinkling for the first time. The laser treatment leads to local hardening areas and wrinkling occurs in the area with the lower strength basic material in every indentation. The experimental and numerical investigation of the laser heat treatment and the influence on the two forming steps are shown.
Combined Computed Tomography and Numerical Modeling for the Analysis of Bending of Additively Manufactured Cellular Sheets: Stephan Rosenthal1; Elliott Jost2; Christopher Saldana2; Till Clausmeyer1; Marlon Hahn1; A. Erman Tekkaya1; 1Institute of Forming Technology and Lightweight Components (IUL), TU Dortmund University; 2Woodruff School of Mechanical Engineering, Georgia Institute of Technology
Additively manufactured (AM) metallic sheets with internal cellular structures are formed in a bending operation. This enables a higher degree of lightweighting potential due to design freedom and strain hardening. Computer tomography (CT) of those structures with wall thicknesses of 0.3 mm reveal manufacturing inaccuracies of the AM-process between the CAD and actual geometry of up to 30%. The CT-data shows that the geometric deviation of the unit cells is periodic. A surface model based on CT-data is used to evaluate volume-meshing strategies in a finite element model, benefiting from the periodicity of the core structure. With the CT-based numerical model, the accuracy in predicting force-displacement response can be increased, when compared to the ideal CAD-based model. It is demonstrated that accurate representation of the actual geometry in the numerical model is critical for a correct prediction of the bending behavior and the investigation of localization phenomena during deformation.
Analysis of Tube Spinning: Eren Can Sarıyarlıoğlu1; Omer Music2; Mustafa Bakkal3; 1Istanbul Technical University and Repkon Machinery; 2TED University; 3Istanbul Technical University
Tube spinning is a continuous bulk forming technique to produce seamless, conical and contoured tubes. Over the last six decades, tube spinning process has been applied in a wide range of engineering applications; especially in automotive, aerospace, nuclear and defense industry. However, the process has seen little or no change, and more importantly, despite a large volume of literature investigating the process, understanding of the process mechanics is limited and the key references are papers published about 50 years ago in the U.S.A. and Japan. This paper investigates the process mechanics, looking into mechanism of deformation, failure modes and process operating window. The process is investigated using a numerical model with implicit time integration and Arbitrary Lagrangian-Eulerian method (ALE). The model has been developed and validated with physical trials using a commercial FE software package and used to provide insight into key aspects of process mechanics.
Fluidity of the Wood Composite Combined with Natural Binder on Injection Molding: Shohei Kajikawa1; Masaya Horikoshi1; Takashi Kuboki1; Soichi Tanaka2; Kenji Umemura2; Kozo Kanayama2; 1The University of Electro-Communications; 2Kyoto University
Research and development for processing technology of naturally-derived material have been demanded for preventing mass disposal of petroleum-derived plastics. Authors have proposed injection molding of new wood composite with natural binder, which is composed of sucrose and citric acid. The wood composite is plasticized to be deformable when heated, and then molding is possible. In this study, effect of the natural binder content and mixture ratio of the sucrose and the citric acid on fluidity of the wood composite on injection molding was investigated. At first, optimum temperature for plasticizing the wood composite was investigated by thermal analysis and extrusion test. Based on these results, injection molding was carried out. Product was obtained successfully when the fluidity of the wood composite was high. The fluidity was improved with an increase of the binder content, and optimum mixture ratio of the sucrose and the citric acid was 75:25.
Development of a New Printing Method Using Soft Material Tools: Yasuharu Yoshikawa1; Yusuke Masegi1; 1Meijo University
Coining and nanoimprint are forming processes for surface micro geometry of metal or plastic. Pattern on the tools of these process is usually produced using precision cutting, photo lithography, ion beam milling and so on. However, these forming methods of pattern need long processing time and high cost. A new printing method for metal using soft material tools is developed. This method uses paper or plastic film with fine pattern produced by laser printer as printing tool. Aluminum disc is compressed with soft material tool between upper and lower flat dies. In order to print in high accuracy and uniformed pattern to metal surface, effects of process conditions to printing are investigated. Experimental results using soft material tools showed that the good condition for high accuracy is changed by combination of average pressure and work piece shape.
Cutting Blades for Food Processing Applications Manufactured Using Innovative Spin Forming: Tim Rostek1; Hanna Makeieva1; Werner Homberg1; 1Paderborn University
Cutting blades for various food processing applications are primarily manufactured using standardized grinding processes at present. This results, on the one hand, in time-consuming and hence expensive production and, on the other hand, means that the surface roughness is not optimized in a microbiological manner, leading to high healthcare costs for foodborne infection. The strength of the cutting blades is additionally less-than-ideal, which causes a high expenditure on wear. Current research work at the Department for Metal Forming Technologies (LUF) is focused on innovative spin forming processes which have high potential for manufacturing parts with an excellent surface roughness in short process times. Along with the process-integrated thermal treatment, this is fundamental for the research and development of improved manufacturing technologies for high-performance cutting blades. This paper looks into innovative process strategies for manufacturing parts with locally graded characteristics, improved surface roughness characteristics and greater strength of the cutting edge.