DOCSLIB.ORG

Prediction and Reduction of Defects in Sheet Metal Forming Dissertation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Prediction and Reduction of Defects in Sheet Metal Forming Dissertation PREDICTION AND REDUCTION OF DEFECTS IN SHEET METAL FORMING DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University Ali Fallahiarezoodar M. S. Graduate Program in Industrial and Systems Engineering The Ohio State University 2018 Dissertation Committee: Taylan Altan, Advisor Farhang Pourboghrat Jerald Brevick Copyright by Ali Fallahiarezoodar 2018 ABSTRACT Sheet metal forming as process of forming a metal blank into a useful part is a major metal forming process. The overall objective of the sheet metal forming process is to form the part within the required tolerances without any defects. Defects in sheet metal forming appeared as tearing, necking, wrinkling, and springback. In the last decade, the advanced high strength steels (AHSS) and high strength aluminum alloys are increasingly used in automotive industry to satisfy the demands for improved safety, fuel efficiency and low-emission of greenhouse gas. However, in general, in high strength materials, low formability and high springback are observed. Therefore, forming of these materials is more challenging than normal mild steels. Several parameters affect the quality of the final part. Blank and tool material, friction and lubrication, and process parameters such as forming speed and temperature can significantly affect the result. Determination of material properties and formability is necessary for tooling and process design. The common methods for determination of material properties required for designing and simulating the sheet metal forming process are reviewed. Also, forming limit diagram as an indication of material formability is studied. The limitations of the forming limit diagram are presented and a practical method for developing the forming limit diagram is presented. Friction and lubrication play an important role in providing high quality parts from a deep drawing process. Friction conditions depend on sheet and tool material, surface qualities, the type of the lubricant and process conditions such as contact pressure, sliding velocity, and temperature. Laboratory tests for evaluating deep drawing lubricants should be designed to emulate the conditions of actual forming processes. The cup drawing test and twist compression test are compared for evaluating metal stamping iii lubricants. Effects of contact pressure and sliding velocities on lubricant performance are evaluated. Also, numerical simulations are developed to predict the temperature increase in the part during each test. Results showed that the testing condition in the cup drawing test is closer to actual deep drawing operations and this test is more proper for evaluating metal stamping lubricants compared to the twist compression test. Springback affects the dimensional accuracy and final shape of stamped parts. Accurate prediction of springback is necessary to design dies that produce the desired part geometry and tolerances. Springback occurs after stamping and ejection of the part because the state of the stresses and strains in the deformed material has changed. To accurately predict springback through finite element analysis, the material model should be well defined for accurate simulation and prediction of stresses and strains after unloading. Despite the development of several advanced material models that comprehensively describe the Bauschinger effect, transient behavior, permanent softening of the blank material, and unloading elastic modulus degradation, the prediction of springback is still not satisfactory for production parts. Dies are often recut several times, after the first tryouts, to compensate for springback and achieve the required part geometry. Material properties which affect the springback are studied and effect of each property is investigated. Results showed that the E-modulus is the most important material property defining the elastic recovery of the material and springback. A methodology for determination of an average E-modulus that can provide accurate springback prediction is presented. The method is expanded to determine the variation of E-modulus with plastic strain to simulate the springback in real industrial part and obtain reasonably accurate springback prediction before manufacturing a real die. Finally, effect of post-stretching method on reduction of springback is investigated both experimentally and numerically. iv DEDICATION To my beloved family v ACKNOWLEDGMENTS First and foremost, I would like to thank God Almighty for giving me the strength, knowledge, ability and opportunity to undertake this research study and to persevere and complete it satisfactorily. Without his blessings, this achievement would not have been possible. I would like to thank my advisor, Dr. Taylan Altan, for providing me the value of science with continuous assistance and support. He was the Key to my success. I am also grateful to Dr. Brevick and Dr. Pourboghrat for the constant support to improve my dissertation. I wish to thank the sponsors of the following research: Honda America, Shiloh, Posco, Nucor, Aida America, GM, and the other CPF member companies, as well as all of the personnel of those companies which assisted me. I also thank my fellow coworkers and friends of the Center for Precision Forming (CPF). Adam Groseclose, Suraj Appachu Palecanda Krishna, Tingting Mao, Ruzgar Peker, David Diazinfante Hernandez, Pedro Stemler, Fabian Bader, Advaith Narayanan, Berk Aykas, Tanmay Gupta, Aanandita Katre, Pratik Mehta, Josh Hassenzahl, and Linda Anastasi, as well as many others, all helped me more than they can possibly imagine. Lastly, I would like to thank my parents, whose love and guidance are with me in whatever I pursue. They are the foundation to which my education is built on and will continue to push me to bigger and better things. Most importantly I wish to thank my loving and supportive wife, Mina who provides unending inspiration. vi VITA Master of Science (Mechanical Engineering) .................................................. September 2010 Bachelor of Engineering (Mechanics of Agricultural Machines) ..................... June 2008 PUBLICATIONS 1. A. Fallahiarezoodar, R. Peker, T. Altan, Temperature Increase in Forming of Advanced High- Strength Steels – Effect of Ram Speed Using a Servodrive Press, Journal of Manufacturing Science and Engineering, Vol 138, pp 094503-1-94503-7, 2016. 2. A. Fallahiarezoodar, A. Katre, T. Altan, Predicting springback when bending AHSS and aluminum alloys, Part I, Stamping journal, pp 12-13, November/December 2016. 3. A. Fallahiarezoodar, Z. Yin, T. Altan, Controlling material flow in drawing operations CNC hydraulic cushions help improve drawability, Stamping journal, pp 16-17, May/June 2016. 4. A. Fallahiarezoodar, K, Drotleff, M. Liewald, T. Altan, Lightweighting in automotive industry using sheet metal forming-advances and challenges, 5th international conference on accuracy in forming technology, Chemnitz, 2015. 5. A. Fallahiarezoodar, L. Ju, T. Altan, Use of FE simulation and servo press capabilities in forming of AHSS and aluminum alloys, Key engineering materials, Vol 639, pp 13-20, 2015. 6. A. Fallahiarezoodar, T. Altan, Determining flow stress data by combining uniaxial tensile and biaxial bulge test, Stamping journal, pp 16-17, September/October 2015. 7. A. Fallahiarezoodar, R, Peker, T. Altan, Heat generation in forming of AHSS, Stamping journal, pp 12-13, March/April 2015. 8. A. Fallahiarezoodar, J. Dykeman, T. Altan, Using the frictionless dome test to determine flow stress data, Stamping journal, pp 14-15, November/December 2014. 9. A. Fallahiarezoodar, M.R. Abdul Kadir, M. Alizadeh, Sangeetha Naveen, T. Kamarul, Geometric variable designs of cam/post mechanisms influence the kinematics of knee implants, Knee Surgery, Sports Traumatology, Arthroscopy Volume 22, Issue 12, pp 3019-3027, 2014. 10. M. Heydari, M. R. Abdulkadir, J. Kashani, A. Fallahiarezoodar, M. Alizadeh, Influences of rheumatoid arthritis on elbow: A finite element analysis, Journal of Advanced Science Letters, Volume 19, Number 11, pp. 3219-3222(4), November 2013. vii 11. M Ailzaadeh, M.R. Abdul Kadir, M. Mohd Fadhil, A. Fallahiarezoodar, B. Azmi, M. R. Murali, T. Kamarul, The use of X shaped cross-link in posterior spinal constructs improves stability in thoracolumbar burst fracture: A finite element analysis, Journal of Orthopaedic Research, 31(9):1447-54, 2013 Sep. 12. M. Heydari, M. R. Abdulkadir, A. Fallahiarezoodar, Muhamad Noor Harun, Mina Alizadeh, and Jamal kashani., Biomechanical assessment of unconstrained elbow prosthesis after total elbow replacement: A finite element analysis. Journal of Applied Mechanics and Materials, Vol. 234, pp 7-10, 2012. FIELDS OF STUDY Major Field: Industrial and Systems Engineering Specialization: Manufacturing viii TABLE OF CONTENTS Abstract ................................................................................................................................................. iii Dedication ............................................................................................................................................. v Acknowledgements ............................................................................................................................... vi Vita ........................................................................................................................................................ vii List of Figures ......................................................................................................................................
Load more

Recommended publications
  • Integrating Cold Forging and Progressive Stamping for Cost
    Precision Cold Forging Progressive Stamping Enables Cost Effective Production of Complex Parts Overview Both Cold Forging and Precision Stamping are proven technologies used in the fabrication of parts for a wide range of industries. Many of our previous Tech Bulletins have detailed the benefits of each technology, and in several cases, these processes are thought of as an either- or choice. This Tech Bulletin provides insights into how combining these technologies in a process known as Precision Cold Forging Progressive Stamping can provide significant synergies and additional benefits for the cost-effective production of complex parts that cannot easily be created by either technique alone. What is Cold Forging? As detailed in other Interplex Tech Bulletins, Cold Forging is essentially an impact forming process in which billets of raw material are compressed and reformed into a part’s desired shape. Cold Forging offers the key benefits of lower costs, rapid high-volume throughput, high part strength, and very efficient material utilization. This, in comparison to processes like machining that remove Figure 1 – Cold Forged significant amounts of raw material rather than simply reforming all the Automotive Seat Belt Gear material into the desired shape. What is Precision Stamping? Precision Stamping is another proven technology that uses a press and die to form sheet metal, blanks or coil material into desired shapes. Variations of the stamping process can effectively yield several different output results including bending, embossing, flanging, coining, etc. Like Cold Forging, Precision Stamping typically offers high material utilization with minimal waste and can also deliver high-volume production results.
    [Show full text]
  • 1 Modeling and Optimization in Manufacturing by Hydroforming and Stamping
    13 1 Modeling and Optimization in Manufacturing by Hydroforming and Stamping Hakim Naceur1 and Waseem Arif2 1Université Polytechnique Hauts-de-France, CNRS, INSA Hauts-de-France, UMR 8201-LAMIH, F-59313 Valenciennes, France 2University of Gujrat, Mechanical Engineering Department, Gujrat, Pakistan 1.1 Introduction Due to the strict environmental policies and shortage of energy, the manufacturing industries are pressurized to cut down the raw material cost and to save energy. This is particularly true in the automotive industry, where manufacturers are obliged to develop advanced techniques to reduce the pollution by reducing the fuel con- sumption without significant increase in the cost. Among all the manufacturing techniques, the stamping and hydroforming methods hold a top position among the cold sheet metal forming processes due to the versatility of components that can be produced and high production rates [1]. Stamping and hydroforming processes are intensively used in various industrial sectors such as transportation, car body in white (Figure 1.1), household appliances, metal packaging, etc. The use of fluid pressure has been remarkably increased in sheet metal form- ing processes since it allows a superior final surface quality of the workpiece than standard deep drawing process [2–4]. In particular, sheet hydroforming process has great potential to manufacture body-in-white parts with consistently extreme level of ultimate tensile strength, reduced weight, geometrical accuracy, and minimum tol- erances. It has certain advantages, e.g. more uniform thickness distribution of the final workpiece component, lower tooling cost, and versatility to produce partswith different geometries using the same setup [5]. The worldwide acknowledgment of these two sheet metal forming processes is largely due to the external pressure from the government legislators to develop lightweight products.
    [Show full text]
  • Problem- Solving Guide
    Common Stamping Problems Problem- Manufacturers know that punching can be the most cost-effective process for making Dayton Progress Corporation holes in strip or sheet metal. However, as the part material increases in hardness to 500 Progress Road Solving accommodate longer or more demanding runs, greater force is placed on the punch P.O. Box 39 Dayton, OH 45449-0039 USA and the die button, resulting in sudden shock, excessive wear, high compressive loading, and fatigue-related failures. Dayton Progress Detroit Guide 34488 Doreka Dr. The results of some of these Fraser, MI 48026 problems are shown in the Dayton Progress Portland photos on this page. 1314 Meridian St. Portland, IN 47371 USA Dayton Progress Canada, Ltd. 861 Rowntree Dairy Road Woodbridge, Ontario L4L 5W3 Punch Chipping & Point Breakage Dayton Progress Mexico, S. de R.L. de C.V. Access II Number 5, Warehouse 9 Chips and breaks can be caused by Benito Juarez Industrial Park press deflection, improper punch Querétaro, Qro. Mexico 76130 materials, excessive stripping force, Dayton Progress, Ltd. and inadequate heat treatment. G1 Holly Farm Business Park Honiley, Kenilworth Slug Jamming Warwickshire CV8 1NP UK Slug jamming is often the result Dayton Progress Corporation of Japan of improper die design, worn-out 2-7-35 Hashimotodai, Midori-Ku die parts, or obstruction in the slug Sagamihara-Shi, Kanagawa-Ken relief hole. 252-0132 Japan Slug Pulling Dayton Progress GmbH Adenauerallee 2 Slug pulling occurs when the slug 61440 Oberursel/TS, Germany sticks to the punch face upon withdrawal and comes out of the Dayton Progress Perfuradores Lda Zona Industrial de Casal da Areia Lote 17 lower die button.
    [Show full text]
  • Methods Used for the Compaction and Molding of Ceramic Matrix Composites Reinforced with Carbon Nanotubes
    processes Review Methods Used for the Compaction and Molding of Ceramic Matrix Composites Reinforced with Carbon Nanotubes Valerii P. Meshalkin and Alexey V. Belyakov * Mendeleev University of Chemical Technology of Russia (MUCTR), 9 Miusskaya Square, 125047 Moscow, Russia; [email protected] * Correspondence: [email protected]; Tel.: +7-495-4953866 Received: 2 August 2020; Accepted: 11 August 2020; Published: 18 August 2020 Abstract: Ceramic matrix composites reinforced with carbon nanotubes are becoming increasingly popular in industry due to their astonishing mechanical properties and taking into account the fact that advanced production technologies make carbon nanotubes increasingly affordable. In the present paper, the most convenient contemporary methods used for the compaction of molding masses composed of either technical ceramics or ceramic matrix composites reinforced with carbon nanotubes are surveyed. This stage that precedes debinding and sintering plays the key role in getting pore-free equal-density ceramics at the scale of mass production. The methods include: compaction in sealed and collector molds, cold isostatic and quasi-isostatic compaction; dynamic compaction methods, such as magnetic pulse, vibration, and ultrasonic compaction; extrusion, stamping, and injection; casting from aqueous and non-aqueous slips; tape and gel casting. Capabilities of mold-free approaches to produce precisely shaped ceramic bodies are also critically analyzed, including green ceramic machining and additive manufacturing technologies. Keywords: carbon nanotubes; ceramic matrix composites; compaction; molding; casting; powder mixtures; green bodies; plastic molding powders; slips; polymerizable monomers; solid freeform fabrication; machinery 1. Introduction Compaction molding is an important technological stage in the mass production of technical ceramics and ceramic matrix composites (hereinafter, CMCs).
    [Show full text]
  • The Simulation of Cold Volumetric Stamping by the Method of Transverse Extrusion
    MATEC Web of Conferences 224, 01105 (2018) https://doi.org/10.1051/matecconf/201822401105 ICMTMTE 2018 The simulation of cold volumetric stamping by the method of transverse extrusion Anatoly K. Belan1, Vladimir A. Nekit1,*, and Olga A. Belan1 1Nosov Magnitogorsk State Technical University, Lenin Street, 38, Magnitogorsk city, Chelyabinsk Region, Russian Federation, 455000 Abstract. The article is devoted to the theoretical study and development of the production process of manufacturing rod products with larger heads by transverse extrusion. For carrying out researches the elastic-plastic finite- element model based on the variation principle was chosen. This model, due to the development of a complex of boundary and initial conditions, has been adapted to the scheme of volume stamping of the fasteners and implemented in the form of a software package in the system DEFORM 3D.The paper presents the results of computer simulation of the technology of manufacturing the mortgage bolt 1 Introduction With the development of mechanical engineering, automotive and construction, there is a growing need for sophisticated modern fasteners which allows you to create strong, high- performance, reliable and durable connections. These fasteners contain: flanged fasteners, self-drilling and self-tapping screws, their use greatly simplifies and speed up installation work [1]. Fig. 1. Items with long cone and an enlarged head. To reduce terms of development and introduction of new types of fasteners the systems of the automated design and modelling allowing to model several options of the technology * Corresponding author: [email protected] © The Authors, published by EDP Sciences. This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (http://creativecommons.org/licenses/by/4.0/).
    [Show full text]
  • The Dynisco Extrusion Processors Handbook 2Nd Edition
    The Dynisco Extrusion Processors Handbook 2nd edition Written by: John Goff and Tony Whelan Edited by: Don DeLaney Acknowledgements We would like to thank the following people for their contributions to this latest edition of the DYNISCO Extrusion Processors Handbook. First of all, we would like to thank John Goff and Tony Whelan who have contributed new material that has been included in this new addition of their original book. In addition, we would like to thank John Herrmann, Jim Reilly, and Joan DeCoste of the DYNISCO Companies and Christine Ronaghan and Gabor Nagy of Davis-Standard for their assistance in editing and publication. For the fig- ures included in this edition, we would like to acknowledge the contributions of Davis- Standard, Inc., Krupp Werner and Pfleiderer, Inc., The DYNISCO Companies, Dr. Harold Giles and Eileen Reilly. CONTENTS SECTION 1: INTRODUCTION TO EXTRUSION Single-Screw Extrusion . .1 Twin-Screw Extrusion . .3 Extrusion Processes . .6 Safety . .11 SECTION 2: MATERIALS AND THEIR FLOW PROPERTIES Polymers and Plastics . .15 Thermoplastic Materials . .19 Viscosity and Viscosity Terms . .25 Flow Properties Measurement . .28 Elastic Effects in Polymer Melts . .30 Die Swell . .30 Melt Fracture . .32 Sharkskin . .34 Frozen-In Orientation . .35 Draw Down . .36 SECTION 3: TESTING Testing and Standards . .37 Material Inspection . .40 Density and Dimensions . .42 Tensile Strength . .44 Flexural Properties . .46 Impact Strength . .47 Hardness and Softness . .48 Thermal Properties . .49 Flammability Testing . .57 Melt Flow Rate . .59 Melt Viscosity . .62 Measurement of Elastic Effects . .64 Chemical Resistance . .66 Electrical Properties . .66 Optical Properties . .68 Material Identification . .70 SECTION 4: THE SCREW AND BARREL SYSTEM Materials Handling .
    [Show full text]
  • Design of Forming Processes: Bulk Forming
    1 Design of Forming Processes: Bulk Forming Chester J. Van Tyne Colorado School of Mines, Golden, Colorado, U.S.A. I. BULK DEFORMATION atures relative to the melting point of the metal. Hot working occurs at temperatures above tJllerecrystalliza- Bulk defonnation is a metal-fonning process where the tion temperature of the metal. There is a third temper- defonnation is three-dimensional in nature. The pri- ature range, warm working, which is being critically mary use of the tenn bulk deformation is to distinguish it examined due to energy savings and is, in some cases, from sheet-fonning processes. In sheet-forming opera- used by industries. tions, the defonnation stressesare usually in the plane of the sheet metal, whereas in bulk defonnation, the 1. Cold Working Temperatures defonnation stresses possess components in all three Cold working usually refers to metal deformation that is coordinate directions. Bulk defonnation includes metal carried out at room temperature. Th,~ phenomenon working processes such as forging, extrusion, rolling, associated with cold work occurs wht:n the metal is and drawing. deformed at temperatures that are about 30% or less of its melting temperature on an absolute temperature scale. During cold work, the metal ,~xperiences an II. CLASSIFICATION OF DEFORMATION increased number of dislocations and elltanglement of PROCESSES these dislocations, causing strain hardening. With strain hardening, the strength of the metal increases with The classification of deformation processescan be done deformation. To recrystallize the metal, ;i thermal treat- in one of several ways. The more common classification ment, called an anneal, is often needed. During anneal- schemes are based on temperature, flow behavior, and ing, the strength of the metal can be drastically reduced stressstate.
    [Show full text]
  • Application of Forming Limit Diagram and Yield Surface Diagram to Study Anisotropic Mechanical Properties of Annealed and Unannealed Sprc 440E Steels S.P
    INTERNATIONAL CONFERENCE ON RECENT ADVANCEMENT IN MECHANICAL ENGINEERING &TECHNOLOGY (ICRAMET’ 15) Journal of Chemical and Pharmaceutical Sciences ISSN: 0974-2115 APPLICATION OF FORMING LIMIT DIAGRAM AND YIELD SURFACE DIAGRAM TO STUDY ANISOTROPIC MECHANICAL PROPERTIES OF ANNEALED AND UNANNEALED SPRC 440E STEELS S.P. Sundar Singh Sivam, M. Gopal, S.Venkatasamy, Siddhartha Singh Department of Mechanical Engineering, SRM University, Kancheepuram District, Kattankulathur- 603203, Tamil Nadu, India *Corresponding author: Email: [email protected] ABSTRACT Sheet metal forming is a vital operation in the manufacturing of a number of automobile components. The quality of the formed component depends largely on the formability of the sheet metal. In the present study, the formability of SPRC440E steel sheets by deep drawing have been characterized and the forming limit diagram (FLD’s) have been experimentally determined by conducting punch stretching experiments on unannealed and annealed SPRC440E sheets using a double acting hydraulic press. Formability observed from FLD’s has been correlated with microstructure, mechanical properties and formability parameters. From the experimental results, it has been found that the sheets have a favorable grain size and mechanical properties to meet the requirements of good formability for annealed SPRC 440E steel. It is also confirmed by Erichsen cupping test. It was also observed that metal stretchability increases with increasing value of strain hardening exponent (n) and drawability increases with increasing value of normal anisotropy (rm) value. It is well known that FLD and anisotropic properties of a substance sensitively depends upon its yield surface diagram. Therefore a suitable yield criterion is chosen to describe the plastic behavior and predict the nature of FLD of SPRC440E.
    [Show full text]
  • Evaluation of Formability and Determination of Flow
    EVALUATION OF FORMABILITY AND DETERMINATION OF FLOW STRESS CURVE OF SHEET MATERIALS WITH DOME TEST THESIS Presented in Partial Fulfillment of the Requirements for the Degree Master of Science in the Graduate School of The Ohio State University By Ji You Yoon Graduate Program in Mechanical Engineering The Ohio State University 2012 Master's Examination Committee: Taylan Altan, Advisor Jerald Brevick Copyright by Ji You Yoon 2012 Abstract Determination of flow stress curve of sheet material is important for designing stamping process efficiently. Entering accurate flow stress curve to FE simulations is necessary to obtain reliable results from simulations. Furthermore, in most Advanced High Strength Steels (AHSS), material properties may vary from coil to coil and that can affect to product quality. The dome test is a material test to evaluate formability and determine the flow stress curve of the sheet materials. The dome test is a biaxial test which consequently achieves greater maximum true strain without localized necking compared to that of uniaxial tensile test. As a result, the flow stress curve obtained from the dome test can be determined up to larger strains than in tensile test. This reduces possible errors from extrapolation of flow stress curve obtained from tensile test. FE simulations are performed in order to understand the deformation process in the dome test and to develop database for computer program, PRODOME, (MATLAB). With PRODOME, flow stress curve is calculated (determining K and n values in Hollomon’s Law (σ=Kεn)) by inputting dome test outputs of punch force vs. stroke. It is calculated by using inverse analysis method.
    [Show full text]
  • Rotary Swaging What Is Rotary Swaging?
    Rotary Swaging What is Rotary Swaging? Net-Shape-Forming Rotary swaging is a process for precision forming of tubes, bars or wires. lt belongs to the group of net-shape-forming processes, of which one of the characteristics is that the finished shape of the formed workpieces is obtained without, or with only a minimum amount of further final processing by machining. The forming dies of the swaging machine are arranged concentric around the workpiece. The swaging dies perform high frequency radial movements with short strokes. The stroke frequencies are ranging from 1,500 to 10,000 per minute depending on the machine size, with total stroke lengths of 0.2 to 5 mm. The radial movements of the dies are for most applications simultaneous. Usually one die set consists of four die segments. Depending on the application and on the size of the machine, alternatively sets of two, three, six or in special cases up to eight dies can be used. To prevent the formation of longitudinal burrs at the gaps between the dies, there is a relative rotational movement between dies and the workpiece. The swaging dies rotate around the workpiece, or alternatively the workpiece rotates Operation principle between the dies. For production of non-circular forms the dies and the workpiece are stationary without rotational movement. Rotary swaging is an incremental forming process where the oscillating forming takes place in many small processing steps. One of the advantages of the incremental forming process compared to the continuous processes is the homogenous material forming. Rotary swaging achieves very high forming ratios in only one processing step as the deformability of the material is uniformly distributed over the cross-section.
    [Show full text]
  • Process Analysis and Design in Stamping and Sheet
    PROCESS ANALYSIS AND DESIGN IN STAMPING AND SHEET HYDROFORMING DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Ajay D. Yadav, M.S. * * * * * The Ohio State University 2008 Dissertation Committee: Approved by: Professor Taylan Altan, Adviser Associate Professor Jerald Brevick -------------------------------------------------- Professor Gary L. Kinzel Adviser Industrial and Systems Engineering Graduate Program ABSTRACT This thesis presents initial attempts to simulate the sheet hydroforming process using Finite Element (FE) methods. Sheet hydroforming with punch (SHF-P) process offers great potential for low and medium volume production, especially for forming (a) lightweight materials such as Al- and Mg- alloys and (b) thin gage high strength steels (HSS). Sheet hydroforming has found limited applications and is thus still a relatively new forming process. Therefore, there is very little experience-based knowledge of process parameters (namely forming pressure, blank holder tonnage) and tool design in sheet hydroforming. For wide application of this technology, a design methodology to implement a robust SHF-P process needs to be developed. There is a need for a fundamental understanding of the influence of process and tool design variables on hydroformed part quality. This thesis addresses issues unique to sheet hydroforming technology, namely, (a) selection of forming (pot) pressure, (b) excessive sheet bulging and tearing at large forming pressures, and (c) methods to avoid leaking of pressurizing medium during forming. Through process simulation and collaborative efforts with an industrial sponsor, the influence of process and tool design variables on part quality in SHF-P of axisymmetric punch shapes (cylindrical and conical punch) is investigated.
    [Show full text]
  • Aluminum Stamping Solutions
    Select the Coating that Matches Commitment to Quality & Customer Satisfaction Aluminum Your Speci c Needs Dayton Lamina is a leading manufacturer of tool, die and mold components for the metal-working and plastics industries. As a customer-focused, world-class supplier of choice, we provide Stamping Abrasive Wear Adhesive Wear the brands, product breadth, distribution network and technical Regardless of the end product(s) your Common Abrasion, pitting, cavitation, striation, Galling, pick-up, sticking, welding, company manufactures, you can Names etc. etc. support for all your metal forming needs. Solutions improve the length of run time, reduce Processes Hard sheet material—jagged edges Soft sheet material Piercing, shearing, etc. Drawing, extruding, etc. Our goal is to give our customers the most innovative and value- changeover time, improve uptime, Sliding wear—along direction of Perpendicular to direction of forming added products and services. and get more for your stamping dollar forming by selecting the type of coating that Process temperature may be too high Process temperature may be too matches your individual operational or low high Clearances may be too tight Clearances may be tight capabilities. Solutions Increase surface hardness Increase lubrication The chart on the right describes the Increase clearances Choose lower coefficient coating causes, e ects, and solutions for abrasive Choose high thermal resistance Choose high thermal resistance coating coating wear and adhesive wear. The slider Increase clearances graph following shows the relative suitability for each type of treatment/ Abrasive Wear Adhesive Wear coating in both of those categories. The bubble chart shows the relationship be- tween service temperature, coe cient Uncoated XNP XCN CRN XNT Tool XNM XCD XCDP of friction, and hardness of the coating.
    [Show full text]