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Cold forging processes

Please find information, research projects and publications regarding cold forging processes in this section.

Cold Forging

Projects

  • Microforming of bulk metal components from band material, Institute of Manufacturing Technology (LFT) Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany:

    The interest on mass production of small complex metal components is currently fostered by fields like electronics and micromechanics. A possible approach is seen in a multi-step bulk forming process, limited among scaling problems by handling difficulties between the forming stages. A radical simplification of the positioning of the workpiece is seen in a process in which a metal strip acts both as raw material and support of the workpiece through the different forming stages.  The results of these studies will lead up to a definition of the achievable geometries and a review of further one- and more step forming processes from the strip plane. The finite element simulation of different single step bulk forming processes has driven to the design of a working tool, which represents the experimental set-up for the study of both the single steps of the process and the entire forming chain. The combined analysis of simulation and experiments aims for an optimization of the metal flow during one and more step bulk forming processes. The study of the strip deformation and of different methods of material flow steering will be further conducted and deeper analyzed. In particular, a higher friction coefficient of the punch and a specific geometry of the blankholder are seen as possible solutions for a more effective extrusion process with minor consequences on the handling.
  • System Development for Automatic Controlled (AC) of Cold Forging Processes, Institute for Metal Forming Technology (IFU) University of Stuttgart / Germany – Status report July 2013:

    Increasing diversity of variants of parts shape today demands high flexibility of bulk metal forming processes in industry. Moreover flexible fabrication of components means quick reaction to production disruptions and design changes due to volatile customer requirements. Expanding of forming limits or technical advancements of cold forging processes for that reason often demand process combinations and/or additional moveable tool axis. Furthermore automatic controlled tool axis integrated into the cold forging die provides the possibility to react on unexpected process fluctuations during series production leading to net-shape manufacturing. Main objective of this project is the development of a modular designed material flow control system for cold forging applications.

  • Environmentally friendly process chains in cold forging by abdication of zinc phosphate conversion layers,  Institute for Production Engineering and Forming Machines (PtU) Technical University of Darmstadt, Germany:

    Cold forging processes provide a high dimensional accuracy and a good material utilization. Due to high tribological loads, which occur during forming, complex separation and lubrication layers are used to prevent wear and failure of expensive forming tools. Hence, zinc phosphate coatings as separation layers and soap as a lubricant are used for the forging of steel, though the application and use of zinc phosphate coatings come along with several environmentally drawbacks. Objective of this research project is to gather basic knowledge for the zinc phosphate-free, multistage cold forging of billets.

  • Tribology of stainless steels, Institute for Production Engineering and Forming Machines (PtU) Technical University of Darmstadt, Germany:

    Stainless steel has an increasing importance for cold forging. However, there are high demands on the tool and the tribological system. Especially the lubricant needs further investigation and, therefore, in a first step the tribological loads must be defined. Thus, eight different cold forging processes have been simulated. It could be shown that the sliding distance, the surface enlargement and the relative velocity in comparison to the cold forging of low alloy steel do not change. Though, the contact normal stresses and the temperature tremendously rise up. In a second step, Sliding Compression Tests have been conducted with common tribological systems as well as new environmentally friendly single bath systems.

  • Load oriented component properties for lightweight and high performance applications through efficient, optimized cold forging processes, Institute of Manufacturing Technology (LFT) Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany:

    The optimization of components for lightweight and high performance applications by using the advantages of cold forging, e.g. strain hardening and orientation of fibers was aim of the project. Especially the influence of the cold forging process on the fatigue strength of components was analyzed. For the investigations fatigue tests have been conceptually designed and executed to determine the correlations between properties and strength of the components. Furthermore, the properties of the components, for example the distribution of true strain and residual stresses, have been calculated using numerical simulations. For small numbers of load cycles the hardness is the important factor in terms of fatigue strength, for the endurance limit the surface properties and residual stresses are important.

  • Dynamic strength of tool steels, Institute of Manufacturing Technology (LFT) Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany:

    Study, funded by the German Cold Forging Group (GCFG) In cold forging the tools have to resist highest cyclic loads because of the high flow stress of the workpiece material. Due to the cyclic loading of the tool during the forging process a main failure cause are fatigue cracks. According to the SVL-concept a tool failure due to fatigue must be expected if the maximum process load is higher than the fatigue strength of the tool material. Thus, fatigue parameters of the used tools steels are very important for the tool- and the process-layout. In the context of the study, Woehler curves for the powder-metallurgical steels CPM1V with a hardness of 59 HRC and ASP2013 with a hardness of 60 HRC have been identified. The experiments were carried out with an electromechanical resonance pulsator using a customized tension/compression specimen. The load amplitude of the Woehler experiments was up to 1,600 N/mm² and the level of the mean stress was varied between -640 and 0 N/mm². Applying a compressive mean stress is comparable to the case of a prestressed die. The created Woehler curves are covering the range from low cycle fatigue with 3·103 load cycles up to high cycle fatigue with 106 load cycles. Hence, the results of the study are a good basis for the layout of forging tools where a lifetime of at least 105 load cycles is expected in many cases.

  • Catalogue for cemented carbides, Institute of Manufacturing Technology (LFT) Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany:

    Study, funded by the German Cold Forging Group (GCFG) Aim of this study is the development of a catalogue which recommends WC-Co-based cemented carbides for standard tooling applications in cold forging industry. In order to enable comparison of different cemented carbide grades criteria for a categorization of available grades in cold forging were defined. Moreover the applied grades in cold forging industry were collected in a representative survey among the members of the GCFG. In this regard it could be shown that a large variety of cemented carbide grades is used for cold forging tools. In a further step the applied grades were categorized in terms of their mechanical properties.

  • Integrative process and material development of a hardenable AFP-steel for energy-efficient and distortion-reduced manufacturing for cold formed high-strength massive components, Institute for Metal Forming (IMF)TU Bergakademie Freiberg, Germany:

    The aim is to develop a novel curable AFP steel and its production technology for a steel that is quite soft during cold forming and has a material properties compared to bolts and screws of property class 12.9 after low temperature annealing.

  • MicrOmega - Precision mechanics: development of an innovative technology for production, through micro-forming of components characterised by complex geometry and high level of dimensional accuracy, in collaboration with Officine Meccaniche OMEGA (2005-2009), Italy:

    The project aimed at developing a virtual environment based on FEM simulation tools in order to design cold forging operations of mini-components for automotive industry.

  • Sacmaform - Software for the loads prediction in cold forging, in collaboration with Sacma Limbiate (2009), Italy:

    The project aimed at developing a SW for the calculation of the forging loads and energies for the most common cold forging operations. The SW has been developed in collaboration with University and has been commercialized by the company.

  • Development of high accuracy forging technology for Magnesium (2011-2019), Korea.

  • Friction measurement by the tip test for cold forging, Korea

  • Design and manufacturing technology development of high-performance air-conditioning system for electric automotive (Magnesium alloy forging), Korea

Publications

  • Zhang Y, Hu CL, Zhao Z, et al. Low cycle fatigue behaviour of a Cr-Mo-V matrix-type high-speed steel used for cold forging. Materials and Design, 2013, 44: 612-621, China
  • Zhang Y, Hu CL, Zhao Z, et al. Fatigue property of cold forging tool material high speed matrix steel based on strain-controlled fatigue experiments at room temperature. Journal of Shanghai Jiaotong University 2012, 46(10):1632-1636. (in Chinese). 
  • She DS, Yue W, Fu ZQ, et al. The effect of nitriding temperature on hardness and microstructure of die steel pre-treated by ultrasonic cold forging technology. Materials & Design, 2013, 49: 392–399.     
  •  Wu XX, San XY, Liang XG, et al. Effect of stacking fault energy on mechanical behavior of cold-forging Cu and Cu alloys. Materials & Design, 2013, 47: 372–376.                                                  
  • Liewald, M.; et al.: Identification of innovative process chains for cold forging. In: Liewald, M. (Edit.), New Developments in Forging Technology, MAT INFO Werkstoffinformationsgesellschaft mbH, Frankfurt/M., 2013, pp. 1-32                                                   
  • Liewald, M.; Fritsching, U.; Hajyheydari, E.: Ecoforge – Resource efficient process chains for high performance components. In: Liewald, M. (Edit.), New Developments in Forging Technology, MAT INFO Werkstoffinformationsgesellschaft mbH, Frankfurt/M., 2013, pp. 107-134                                                   
  • Brenneis, M.; Groche, P.: Sensorische Verbindungselemente durch Kaltmassivumformung. 28. Jahrestreffen der Kaltmassivumformer, Düsseldorf, Germany, 2013.                                                   
  • Calmano, S.; Schmitt, S. O.; Groche, P.: Prevention of over-dimensioning in light-weight structures by control of uncertainties during production. Proceedings of International Conference on New Developments in Forging Technology, Fellbach, Germany, 2013.   
  • Hanisch, T.; Filzek, J.; Müller, C.: Tribological Characterization of Industrial Cold Forging Processes by Laboratory Testing. Tribologie + Schmierungstechnik 59, S. 36–40, 2013.                                                   
  • Andreas, K.; Noneder, J.; Engel, U.; Merklein, M.: Application of cemented carbide based forming tools in cold forging. In: Bouzakis, K.-D.; Bobzin, K.; Denkena, B.; Merklein, M. (Edt.): Proc. 10th International Conference THE "A" Coatings in Manufacturing Engineering, 2013, Aachen, 159-169   
  • Andreas, K.; Merklein, M.; Engel, U.: Fatigue Behavior of Cemented Carbide Based Forming Tools. In: Proceedings of the 18th Plansee Seminar, 2013, Reutte, in print                                                   
  • Koch, J.; Merklein, M.: Cold forging of closely-tolerated functional components out of blanks – possibilities of the new process class sheet-bulk metal forming. In: Ishikawa, T. (Edt.): Proceedings of the 6th JSTP International Seminar on Precision Forging, 2013, Kyoto, Japan, 109-112                                                   
  • Kroiß, T.; Engel, U.: Optimization of tool and process design for the cold forging of net-shape parts by simulation. In: Denkena, B.; Hollmann, F. (edtrs): Process Machine Interactions.Heidelberg, New York, London: Springer 2012. 419-438                                                   
  • Reiß, A.; Engel, U.; Merklein, M.: Investigation on the influence of manufacturing parameters on the fatigue strength of components. Key Engineering Materials, 554-557(2013), 280-286                                       
  • Stellin, T.; Merklein, M.; Engel, U.: Investigation on a Microextrusion Process of Parallel Protrusions from Metal Strip. In: M. Jun, S. Park (Edt.): Proceedings of the 8th International Conference on Micro Manufacturing, 2013, Victoria, CA, 169-174                                                   
  • Stellin, T.; Merklein, M.; Engel, U.: Experimental and Numerical Investigation on a Full Forward Extrusion Process from Metal Strip. In: Humbert Noll, Nadja Adamovic and Stefan Dimov (Edt.): Proceedings of the 9th International Conference on Multi-Material Micro Manufacture, 2012, Singapore: Research Publishing, 163-166                                       
  • van Ravenswaaij, R.; van Tijum, R.; Hora, P.; van den Boogaard, T.; Engel, U.: Towards zero-defect manufacturing of small metal parts. In: IDDRG 2013 Conference Proceedings, 2013, Zurich: Institute of Virtual Manufacturing, ETH Zurich, 87-92                                                   
  • Hoppach, D.; Guk, S.; Kawalla, R.: Untersuchung von Wärmebehandlungen zur Verbesserung der Kaltumformbarkeit. International conference MEFORM 2012, March 28th-30th 2012, Freiberg, pp. 156-167, ISBN 978-3-86012-434-5                                                   
  • Kawalla, R.; Graf, M.; Korpała, G.; Müller, W.: Werkstoffkennwerte für die Massivumformung. International conference MEFORM 2012, March 28th-30th 2012, Freiberg, pp. 1-14, ISBN 978-3-86012-434-5                   
  • Graf, M.; Ullmann, M.; Kawalla, R.: Magnesium – die Herausforderung für die Massivumformung. VDI Conference 2013, Düsseldorf, September 25th-26th 2013                                                   
  • P.F. Bariani, S. Bruschi, A. Ghiotti, Damage Modelling in Cold Forging Process Chains, ICTP 2011, Aachen, Germany.                                           
  • P.F. Bariani, S. Bruschi, A. Ghiotti, M. Simionato , Ductile fracture prediction in cold forging process chains , CIRP Annals - Manufacturing Technology, Volume 60, Issue 1, 2011, Pages 287-290.                                               
  • BORSETTO F., SIMIONATO M., GHIOTTI A., BRUSCHI S., Accurate modelling of the forming process chain to predict cold forged component geometry, Steel Research International, Special Issue, vol.2, 820-825, 2008.     
  • E. CERETTI, C. GIARDINI, Development of an Analytical Model for the Evaluation of Friction Coefficient in Cold Forming, International Journal of Forming Processes, Vol.10, n.3 (2007), 317-355.                                       
  • D.H. Ko, S.K. Lee, Y.N. Kwon, S.W. Kim, B.H. Kim and B.M. Kim, D.C. Ko, Improvement in dimensional accuracy of roll-die-formed clutch hub used in automotive transmission, International Journal of Precision Engineering and Manufacturing, Vol. 13, pp. 237-243, 2012.                                        
  • S.H. Kang, H.S. Kim, Y.S. Lee, Heat Treatment Analysis on Crack Generation during Cooling Process of Large-Sized Forged Product, Steel Research                                                    
  • J. Yoon , H.W. Jeon, J.H. Lee, Process design of cold forging with thick plate for seat recliner parts, Materials and Design, Vol. 49, pp. 449-455, 2013.                                                   
  • K.H. Jung, H.C. Lee, D.K. Kim, S.H. Kang, Y.T. Im, Friction measurement by the tip test for cold forging, Wear, Vol. 286-287, pp.19-26, 2012.           
  • K.H. Jung, Y.T. Im, Determination of a dimensionless equation for shear friction factor in cold forging, Journal of Tribology - Transactions of the ASME, Vol. 135, pp.031102-1-031102-9, 2013.                                           
  • Y.G. Jin, H.M. Baek, S.K. Hwang, Y.T. Im, B.C. Jeon, Continuous high strength aluminum bolt manufacturing by the spring-loaded ECAP system, Journal of Materials Processing Technology, Vol. 212, pp.848-855, 2012.   
  • T.W. Ku, L.H. Kim, B.S. Kang, Multi-stage cold forging and experimental investigation for the outer race of constant velocity joints, Materials & Design, Vol. 49, pp. 368–385, 2013.                                                   
  • T.W. Ku, L.H. Kim, B.S. Kang, Multi-stage cold forging and experimental investigation for the outer race of constant velocity joints, Materials & Design, Vol. 49, pp. 368–385, 2013.                                  
  • M. Milutinović, D. Movrin, T. Pepelnjak: Theoretical and experimental investigation of cold hobbing processes in cases of cone-like punch manufacturing. Int. j. adv. manuf. technol., 2012, vol. 58, iss. 9, pp 895-906                                                   
  • V. Krušič, M. Fabjan: Design of product properties by suitable planning of a cold forging process. International conference on New Developments in Forging Technology, Institute for Metal Forming Technology, University of Stuttgart, June 2013, pp 171-180                                                     

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Upsetting

Projects

  • Flange upsetting at hollow cold forged parts, Institute for Metal Forming Technology (IFU) University of Stuttgart / Germany – Status report July 2013:

    Hollow driveshafts with flanges can be manufactured by upsetting tubular parts. This process is delivering to advantages: high material efficiency and the possibility of lightweight design f component. Unfortunately emerging instability during flange upsetting of tubular parts due to high free upsetting heights is known as a significant process limit. This kind of failure considerably decreases strength of component after forming, especially in case of alternating load application. Within the scope of this project, technological measures, aiming to avoid folding and to extend given process limits, are examined by a correspondingly extensive range of parameters. Beside occurrence of instability two further mechanisms leading to annular folding during upsetting has been determined in this project. Influencing parameters on fold formation without previous buckling behaviour of tubular parts are local strain hardening during upsetting in interaction with the surface quality of inner lateral surface of semi-finished parts. Instability occurrence and critical local strain hardening can be counteracted by a multistage upsetting process with intermediate annealing for example. Moreover process combinations avoiding buckling and providing optimized material flow are focused in experimental investigations.

Publications 

  • S.H. Kang, C.H. Kim, Y.S. Lee, Investigation on Void Closure of 1.5 wt% High Carbon Steel in Upsetting and Cogging Processes, Steel Research International, Metal Forming 2012 Special Edition, pp. 211-214, 2012, Korea.                                                   

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Extrusion

Projects

  • Closed die precision forging technology to form rocker shaft owing to the complexity of the shaft on structure and process,  Henan University of Science and Technology, China:

    According to the Deform-3D simulation of the process, load-stroke curve, law of the metal flow, etc, were acquired, which verified the feasibility and superiority of closed-die forging and was useful to the structural optimization of punch and die subsequently. As for backward extrusion, FE simulation was carried out to study different factors which may have effect on the radial stress towards the inner wall of die. As a result, it was found that properties of extruded material have the strongest effect on the inner wall of die, while the aspect ratio has the weakest.

  • Influences of various punch shapes on radial cold extrusion process of the three-pillar universal joint pin, Hefei University of Technology, China:

    The metal flow, extrusion force and punch equivalent stress distribution were analyzed through the results of simulation and physical experiments. The investigation shows that the optimized taper angle of the punch was beneficial for the metal to fill the cavity, and it can suppress the rapid increase of forming load during the end stage. What’s more, the cold enclosed die forging process was tried to produce planetary gears. A special structure “shunt cavity” was introduced to reduce the forming load. Consequently, it has verified the feasibility of the process.

  • Cold extrusion forming process of internal spline, Chongqing University, China:

    After summarizing and analyzing the forming technology of internal spline tooth, the cold extrusion processes were simulated with FE software DEFORM-3D by direct forming and indirect forming. The indirect forming adding a preforming process could mostly improve the production efficiency, the dimension accuracy of the end surface and the die working life. And the optimized process parameters were obtained.

  • Internal thread formation process, simulation and equipment, Nanjing University of Aeronautics and Astronautics, China:

    Under the same conditions of the process parameters, the internal thread formation by cold extrusion based on low-frequency vibration exhibits a higher rate of thread teeth height and fewer defects of the teeth top than traditional methods, and improve the fatigue strength and surface morphology of the thread so formed. The analysis data during the forming process including extrusion torque and extrusion temperature which made great difference to the thread quality and tap life were derived based on the numerical simulation. The effect of the structural parameters of the extrusion tap on the torque during the forming process is analyzed based on the theoretical formula. The time and frequency analysis of vibration signal for the cold extrusion forming of internal thread was proposed. Dynamic simulation was done for a vibration processing equipment of internal thread formed by cold extrusion based on low frequency vibration.

  • Improvement of the Positional Accuracy of Hollow Semi-finished Products, Institute for Metal Forming Technology (IFU) University of Stuttgart / Germany – Status report July 2013:

    Production of geometrically hollow parts such as transmission shafts with finally pressed gearing normally is based on cold extrusion technology. A metal forming manufacturing chain for producing of such components today after may include cup-extrusion processes, which definitely does have certain limitations in terms of potential part shape design. Current project is focusing on particular investigations to identify and to improve positional accuracy of hollow semi-finished parts within the tool in case of forming hollow gear shafts. Development of error propagation and loss of accuracy during four to five stages of forming sequence starting from produc¬tion of hollow semi-finished part by a backward cup-extrusion process down to final forming of gearing using a combined hollow-forward-hollow-backward extrusion in this project gives deeper focus of interest.

  • Manufacture of a shaft-hub connection by lateral extrusion, Institute for Metal Forming Technology (IFU) University of Stuttgart / Germany – Status report July 2013:

    Nowadays the design of positive locking shaft-hub connections often is limited by manufacturing tole¬ran¬ces due to mechanical machining of shaft and hub. Especially novel contours based on complex cycloids, which demonstrate a high potential in numerical analysis, cannot show its potential in practice due to manufacturing tolerances and assembling clearance. Following new solutions of this study, the final machining of shaft geometry is no longer necessary by joining a shaft-hub connection by lateral extrusion. One part of this investigation embrace a hub made of tempered 42CrMo4 and a shaft made of 16MnCrS5 (GKZ annealed) are joined by lateral extrusion of shaft. Beside tribology conditions or hub's internal profile type the radial preload of the hub is investigated considering high degree filling the cavity of hub along its length. First results using a polygonal hub profile (P3G) show that high friction leads to an increase of radial material flow and thus to a higher degree of filling of cavity. Unfortunately, the increase of degree of cavity filling cause higher radial deformation and higher residual stresses of hub. The properties of the manufactured joints are checked by static and dynamic investigations.

  • Process development for common extrusion of two cylindrical slugs, which are inextricably joined through lateral extrusion, Institute for Metal Forming Technology (IFU) University of Stuttgart / Germany – Status report July 2013:

    The aim of this research project is developing methods for simultaneous extrusion of two cylindrical slugs. One of them is designed tubular with significantly reduced wall thickness; the other one should be designed either as hollow or solid. The separately loaded slugs in this study are inextricably joined through lateral extrusion process. Similar to internal high pressure forming (as known from using liquid or gaseous media) deforming internal work piece generates a kind of inner pressure onto outer tube wall. So one slug is deformed by the internal pressure and its volume fills given cavity by second slug. In contrast to the internal high pressure forming the inner work piece on the one hand acts as a hydroforming medium and on the other hand it generates intended component together with the formed tube. Research project is about to examine general process limits in terms of geometric conditions (wall thickness, diameter ratios, flange height, flange diameter, etc.), to find influence of the movements of the different stamp, the influence of an external contour of the flange, the spring back behavior of different material combinations, die geometries and the preparation and lubrication of the joint.

  • Hydro co-extrusion for Cu-Al hybrid material, Korea

Publications

  • Ying TT, Yang YS, Yu KH, et al. Study on factors affecting radial stress in cold backward extrusion. Journal of Henan University of Science and Technology, 2012, 33(6): 6-10 (in Chinese).                                            
  • Yan JM, Wang CY, Li W, et al. Influences of taper angle of punch on radial cold extrusion process of three-pillar universal joint pin. Forging & Stamping Technology, 2013, 38(2): 81-84.                                               
  • Xia YF, Zheng K, Zhang H, et al. Study on the cold extrusion process of internal spline tooth. Hot Working Technology, 2013, 42(5):120-121,129 (in Chinese).                                                   
  • Lei JB, Zheng XK, Yang XH. The cold extrusion optimization of internal spline.  Forging Equipment and Manufacturing Technology, 2013, (2): 80-81 (in Chinese).                                                   
  • Shi DB, Zuo DW, Huang XL, et al. The HHT-based Vibration Signal of Cold Extrusion Forming Process for the Internal Thread. China Manufacturing Information, 2012, 41(23):100-104 (in Chinese).                                       
  • Huang XL, Li XF, Zuo DW, et al. Optimization of processing parameters for cold extrusion of internal thread based on numerical simulation. Forging & Stamping Technology, 2012, 37(6): 187-192 (in Chinese).                       
  • Huang XL, Li XF, Zuo DW, et al. Effect of structural parameters of extrusion tap on torque during forming process of internal thread by cold extrusion. Forging & Stamping Technology, 2012, 37(6): 187-192 (in Chinese).                                                   
  • Liang YX, Li XF, Zuo DW, et al. Dynamic simulation for a vibration processing equipment of internal thread formed by cold extrusion based on low frequency vibration, Journal of Vibration and Shock, 2012, 31(22): 143-146 (in Chinese).                                                   
  • Liang YX, Li XF, Zuo DW, et al. Experimental research on internal thread formation cold extrusion based on low frequency vibration. Acts Aeronautics et Astronautics Sinica, 2013, 34(2): 442-450 (in Chinese).   
  • Li JP, Xia XS, Wan YY, et al. Technical research on cold extrusion of large size internal gear. Forging & Stamping Technology, 2013, 38(3): 7-11 (in Chinese).                                                   
  • Li JP, Xia BG, Che LC, et al. Numerical simulation and parameter optimization for extrusion process of internal helical part. Forging & Stamping Technology, 2012, 37(6): 123-125 (in Chinese).                       
  • Mletzko, C.; Liewald, M.; Schiemann, T.: Enhancement of Process Limits of Cup Extrusion by Application of Automatic Controlled Additional Tool Axes. In: Proceedings of 29th Forging Industry Technical Conference, Sep. 10.-12. 2012, Cleveland (USA)                                                   
  • Felde, A.; Liewald, M.; Mletzko, C.: Further Development of the Cold Forging Process of Tubular Lightweight Components. Internationale VDI-Fachkonferenz: Getriebeproduktion in der Automobilindustrie, June 19th-20th 2012, Friedrichshafen (Germany), ISBN 978-3-942980-12-8   
  • Dörr, F.; Funk, M.; Liewald, M.; Binz, H.-G.: Herstellung einer Welle-Nabe-Verbindung durch Quer-Fließpressen. Schmiede Journal, Organ des Industrieverband Massivumformung e.V., Hagen, Ausgabe März 2012, ISSN 0933-8330                                                   
  • Görtan, M. O.; Bruder, E.; Groche, P.; Müller, C.: Reprocessing of severely plastic deformed high strength steels by extrusion. Proceedings of the 5th International Symposium on Designing, Toyohashi, Japan, 2012.       
  • Görtan, M.O.; Groche, P.; Bruder, E.; Müller, C.: Cold extrusion of severely plastic deformed high-strength materials. Proceedings of International Conference on New Developments in Forging Technology, Fellbach, Germany, 2013.       
  • Schrader, T.; Engel, U.; Merklein, M.: Influences on wear load in cup extrusion processes. In: Yoshida, Y. (Edt.): Proc. of the 7th ICFG Workshop on Process Simulation in Metalforming, 2012, Gifu, Japan, published on CD                                                   
  • Schrader, T.; Engel, U.; Geiger, M.; Merklein, M.: Mehrlagenbeschichtungen für den beanspruchungsgerechten Einsatz bei Kaltmassivumformwerkzeugen. In: Faulstich, M.; Geiger, M.; Kukla, H.; Wolf, G. (Edt.): Moderne Beschichtungen zum Verschleißschutz von Werkzeugen, 2012, Sulzbach-Rosenberg: DORNER PrintConcept, 181-208                                                   
  • Stellin, T.; Merklein, M.; Engel, U.: Experimental and Numerical Investigation on a Full Forward Extrusion Process from Metal Strip. In: Humbert Noll, Nadja Adamovic and Stefan Dimov (Edt.): Proceedings of the 9th International Conference on Multi-Material Micro Manufacture, 2012, Singapore: Research Publishing, 163-166                                       
  • G. GIULIANO, Process Design of the Cold Extrusion of a Billet using Finite Element Method, Materials & Design, 28, 726-729. Italy                          
  • K. Kim, J. Yoon, Evolution of the Microstructure and Mechanical Properties of AZ61 Alloy Processed by Half Channel Angular Extrusion (HCAE), a Novel Severe Plastic Deformation Process, Materials Science and Engineering A, Vol. 578, pp.160-166, 2013., Korea.                                             
  • M. Terčelj, M. Fazarinc, G. Kugler, I. Peruš: Influence of the chemical composition and process parameters on the mechanical properties of an extruded aluminium alloy for highly loaded structural parts. Constr. build. mater.. [Print ed.], 2013, vol. 44, pp 781-791, Slovenia.                    
                                                    

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Combinations

Projects

  • Control of material flow in combined cold forging of aluminum components using moving cold forging die components, Institute for Metal Forming Technology (IFU) University of Stuttgart / Germany – Status report July 2013:

    Control of material flow during combined extrusion processes by using an automatic controlled additional tool movement axis. Exact knowledge of parameters influencing the flow of material is an important factor to design combi¬ned cold forging processes. Focus of project is to manufacture double-cup-shaped components having one or more branches at one or at both work piece bottom ends. New approach contains a specific kinematic of moving die according to a given velocity profile: so resulting frictional forces and the material flow can be controlled within particular limits. To determine an optimal and robust process design according to predefined work piece geometry software for FEA forming simulation and for CAE multi-objective optimization was coupled. one crucial condition for applying this strategy is given by application of a most accurate simulation model with a low numerical noise. In experimental tests conducted, the movement of die components is automatically controlled along to predefined kinematics which has been optimized in advance.

  • Development of flexible processes on a Multiple Point Servo Press, Institute for Production Engineering and Forming Machines (PtU) Technical University of Darmstadt, Germany:

    Cold forging is mainly applied if high production volumes and narrow tolerances are required. Since the properties of semi-finished parts are exposed to fluctuations, a quality control is required to achieve the desired properties of the products. This requires appropriate sensors to measure the product properties during the process and a controller logic as well as flexible actors, which are able to influence the process. If sensor integration is not possible or not economic, models can be used to predict the current state of the product properties during the process. These models are fed by easily measureable values, like machine and tool parameters, as well as the properties of the semi-finished part or material. The 3D Servo Press can be utilized as a flexible actor, driving tool systems with up to three degrees of freedom. Servo presses in general can combine a flexible ram movement, known from hydraulic presses, with the advantages of mechanical presses with respect to speed and accuracy. Adjusting the ram speed and the stroke length during a ram stroke offers possibilities for improvements in productivity and part quality. Based on the advantages of servo and multiple point servo presses, the 3D Servo Press was designed, which provides a flexible ram motion with three degrees of freedom (DoF). The layout of the 3D Servo Press enables processes with 1-DoF ram motion, like in forging or extrusion, as well as processes with more than one DoF, like in orbital forming. Thus, the concept of the press can be used to realize forming processes with influence on product properties during the process. (Contact: Dipl.-Ing. Stefan Calmano)

Publications

  • J.H. Kim, S.K. Hwang, Y.T. Im, I.H. Son, C.H. Bae, High-strength bolt-forming of fine-grained aluminum alloy 6061 with a continuous hybrid process, Materials Science and Engineering  A, Vol. 552, pp.316-322, 2012.                                                   

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