Project Work. Masters in Product Design Engineering LASER MACHINING STEEL FOR MOULDS: A CASE STUDY. Ayisha Yolchuyeva - PDF

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Project Work Masters in Product Design Engineering LASER MACHINING STEEL FOR MOULDS: A CASE STUDY Ayisha Yolchuyeva Leiria, July, Project Work Masters in Product Design Engineering LASER MACHINING
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Project Work Masters in Product Design Engineering LASER MACHINING STEEL FOR MOULDS: A CASE STUDY Ayisha Yolchuyeva Leiria, July, 2016 Project Work Masters in Product Design Engineering LASER MACHINING STEEL FOR MOULDS: A CASE STUDY Ayisha Yolchuyeva Master s project work carried out under the supervision of Doctor Carlos Alexandre Bento Capela, and Co-supervision of Doctor Henrique de Amorim Almeida and Doctor Mário António Simões Correia, Professors of the School of Technology and Management of the Polytechnic Institute of Leiria. Leiria, July, 2016 Acknowledgement I would like to extend to my thanks to be following people. Thanks to my all professors of the mechanical engineering department of (ESTG) School of Technology and Management and to all teachers from other departments for all the knowledge they have given me throughout my journey in this institution. I would like to express my gratitude to my supervisor Professor Carlos Alexandre Bento Capela for the useful comments, remarks and engagement through the learning process of this master thesis. Furthermore, I would like to thank Professor Henrique Amorim Almeida and Professor Mário S. Correia for introducing me to the topic as well for the support on the way. I II Resumo A maquinação por laser é um processo de fabrico subtrativo não tradicional. Este processo utiliza a energia térmica para remover o material metálico ou não-metálico das superfícies a maquinar. O laser é focado sobre a superfície a ser maquinada, em que a energia térmica do laser é transferida para a superfície, por aquecimento e fusão ou vaporização do material a remover da peça. A maquinação por laser é o processo mais adequado para materiais frágeis, com baixa condutividade, mas pode ser utilizado na maioria dos materiais. O laser é o sistema principal do equipamento e as suas características determinam em grande medida os parâmetros qualitativos e quantitativos do processo tecnológico. Neste trabalho, foram selecionados os parâmetros de processamento por maquinação laser para as operações planeadas e consideradas neste trabalho. Era importante conhecer o processo de maquinação por laser bem como os parâmetros de processamento a utilizar para materiais diferentes. Como consequência da maquinação por laser, o acabamento das superfícies pode apresentar diferentes propriedades, tais como, dureza superficial, rugosidade superficial, atrito superficial e tribologia, etc. Durante este processo, foi possível adquirir conhecimentos sobre o quadro histórico e conceitual do laser, conhecer diferentes parâmetros de laser e como estes podem influenciar as propriedades superficiais das peças maquinadas por laser. Palavras-chave: Laser Fresagem, Micron, de superfície, dureza, rugosidade III IV Abstract Laser beam machining is a non-traditional subtractive manufacturing process, a form of machining, in which a laser is directed towards the work piece for machining. This process uses thermal energy to remove material from metallic or non-metallic surfaces. The laser is focused onto the surface to be worked and the thermal energy of the laser is transferred to the surface, heating and melting or vaporizing the material. Laser beam machining is best suited for brittle materials with low conductivity, but can be used on most materials. The role of the technical equipment in laser milling is to perform a controllable action of the laser radiation on the material to be treated. The laser is the main unit of the equipment and it is characteristics determine to great extent the qualitative and quantitative parameters of the technological treatments. In this work, I had to study the laser milling process parameter selection for process planning operations from start to finish. It was important to have an understanding about laser milling and laser processing parameters for different materials. As a result from the laser milling, the surface finish will have different surface properties such as, surface hardness, surface roughness, friction and tribology etc.. During the process, I gained knowledge about the historical and conceptual framework of laser milling, the different parameters of a laser milling and how the laser milling parameters influence the surface properties of the machined parts. Keywords: Laser Milling, Micron, Surface, Hardness, Roughness V VI List of Figures Figure 1 - Schematic illustration of the laser milling process. [6] Figure 2 - Laser material processing classification from the application point of view [2] Figure 3 - Different laser-based manufacturing processes as a function of power density [4] Figure 4 - Laser milling of three dimensional features using two laser beams A and B oriented at an angle to each other [4] Figure 5 - Electrons are found in specific energy levels of an atom [20] Figure 6 - Schematic process map in terms of combination of laser power density and interaction time for different types of laser material processing involving either no (only heating) or change of state (melting or vapourisation) [21] Figure 7 - What is Micron? [22] Figure 8 - Microfluidic device micro machined in a alumina substrate using a UV laser (JPSA Laser Company) [4] Figure 9 - Micro holes laser machined in polyimide using a UV laser (Potomac Photonics) [4] 20 Figure 10 - Vickers hardness test method [14] Figure 11 - The appeal of an extremely small spot diameter [8] Figure 12 - Ra (Roughness average) graph [17] Figure 13 - Sampling and evaluation length [15] Figure 14 - Covered parameters Rz and Rmax [16] Figure 15 - Graphical construction of Rk parameters [15] Figure 16 - Laser machining 2, 3, 4 µm with 0.2 mm depth Figure 17 - Laser machining 6 µm with 0.2 mm depth Figure 18 - Hardness Vickers Tester (SHIMADZU HMV) Figure 19 - Hardness Vickers Tester (SHIMADZU HMV/during the test process) Figure 20 - Vickers Impression on top of Steel Figure 21 - PerthometerMahr M Figure 22 - Tests with Perthometer Mahr (during the test measuring Ra. Rz, Rmax, Rk roughness parameters) Figure 23 - Hardness Vickers Test results for 2 µm in separate (1-6) spots Figure 24 - Hardness Vickers Test results for 3 µm in separate (1-6) spots VII Figure 25 - Hardness Vickers Test results for 4 µm in separate (1-6) spots Figure 26 - Hardness Vickers Test results for 6 µm in separate (1-6) spots Figure 27 - Hardness Vickers test results in #1 surfaces for different spots laser (2 µm, 3 µm, 4µm, 6 µm) Figure 28 - Hardness Vickers test results in #2 surfaces for different spots laser (2 µm, 3 µm, 4µm, 6 µm) Figure 29 - Hardness Vickers test results in #3 surfaces for different spots laser (2 µm, 3 µm, 4µm, 6 µm) Figure 30 - Hardness Vickers test results in #4 surfaces for different spots laser (2 µm, 3 µm, 4µm, 6 µm) Figure 31 - Hardness Vickers test results in #5 surfaces for different spots laser (2 µm, 3 µm, 4µm, 6 µm) Figure 32 - Hardness Vickers test results in #6 surfaces for different spots laser (2 µm, 3 µm, 4µm, 6 µm) Figure 33 - Ra [µm] function during the demonstrating speed [mm/s] for 2 µm Figure 34 - Rz [µm] function during the demonstrating speed [mm/s] for 2 µm Figure 35 - Rmax [µm] function during the demonstrating speed [mm/s] for 2µm Figure 36 - Rk [µm] function during the demonstrating speed [mm/s] for 2µm Figure 37 - Ra [µm] function during the demonstrating speed [mm/s] for 3µm Figure 38 - Rz [µm] function during the demonstrating speed [mm/s] for 3µm Figure 39 - Rmax [µm] function during the demonstrating speed [mm/s] for 3µm Figure 40 - Rk [µm] function during the demonstrating speed [mm/s] for 3µm Figure 41 - Ra [µm] function during the demonstrating speed [mm/s] for 4µm Figure 42 - Rz [µm] function during the demonstrating speed [mm/s] for 4µm Figure 43 - Rmax [µm] function during the demonstrating speed [mm/s] for 4µm Figure 44 - Rk [µm] function during the demonstrating speed [mm/s] for 4µm Figure 45 - Ra [µm] function during the demonstrating speed [mm/s] for 6 µm Figure 46 - Rz [µm] function during the demonstrating speed [mm/s] for 6µm Figure 47 - Rmax [µm] function during the demonstrating speed [mm/s] for 6µm Figure 48 - Rk [µm] function during the demonstrating speed [mm/s] for 6µm VIII List of Tables Table 1 - Classification of non-traditional removal processes... 7 Table 2 - Basic reference of the micro machining range [22] Table 3 - An outline of topics covered Chapter 3 [1] Table 4 - Values of current intensity to the steel Table 5 - Hardness Test data parameters for 2 µm Table 6 - Hardness Test data parameters for 3 µm Table 7 - Hardness Test data parameters for 4 µm Table 8 - Hardness Test data parameters for 5 µm Table 9 - Hardness Test data parameters for spots and microns Table 10 - Roughness Test data parameterswith the speed for 2 µm Table 11 - Roughness Test data parameters with the speed for 3 µm Table 12 - Roughness Test data parameters with the speed for 4 µm Table 13 - Roughness Test data parameters with the speed for 6 µm IX X List of Symbols ESTG Laser E1,E2 E h v School of Technology and Management Light Amplification by Stimulated Emission of Radiation Excited and ground energy levels Energy difference Planck s constant Characteristic frequency µ Micron m Meter µm Micrometer C Selsius Pa MPa GPa F d L1,L2 λa λq MR(1,2) HV AA Pascal (pressure) Megapascal ( Pa) Gigapascal ( Pa) Load in kf force Standard diagonal size Length of diagonal Average wavelength Square wavelength Material ratio delimiting the core area Hardness Vickers Arithmetic Average XI CLA Ra Rz Rmax Rk Rzi Rpk Rvk Steel Center Line Average Roughness average Maximum height of the profile Maximum roughness height Core roughness depth The single roughness depth Reduced peak height Reduced valleys depth Metal/ Main content: 0.39% C, 1.0% Si, 0.4% Mn, 5.3% Cr, 1.3% Mo, 0.9 % V XII Table of Contents ACKNOWLEDGEMENT... I RESUMO... III ABSTRACT... V LIST OF FIGURES... VII LIST OF TABLES... IX LIST OF SYMBOLS... XI TABLE OF CONTENTS... XIII CHAPTER I INTRODUCTION REPORT STRUCTURE... 1 CHAPTER II STATE OF THE ART LASER BEAM MACHINING BACKGROUND OF LASER TECHNOLOGY LASER TECHNOLOGY HOW DO LASER WORKS BASIC CONSTRUCTION AND PRINCIPLE OF LASING PROCESS CHARACTERISTICS LASER PROCESSING OF ENGINEERING MATERIALS MICRON AND MICROMACHINING TECHNOLOGIES LASER MACHINING AT THE MICRO-SCALE ADVANTAGES AND DISADVANTAGES OF LASER TECHNOLOGY CHAPTER III XIII 3. SURFACE TECHNOLOGY SURFACE HARDNESS SURFACE ROUGHNESS SURFACE ROUGHNESS PARAMETERS CHAPTER IV MATERIALS AND EXPERIMENTAL PROCEDURES STEEL PARAMETERS OF LASER MACHINING PROCESSES SURFACE HARDNESS TEST SURFACE ROUGHNESS TEST CHAPTER V DISCUSSION AND RESULTS SURFACE HARDNESS TESTS RESULTS SURFACE ROUGHNESS TESTS RESULTS CHAPTER VI CONCLUSIONS BIBLIOGRAPHY XIV Chapter I 1.1 Introduction This document is a study about the process of laser milling and laser processing parameters. Along with Professor Carlos Alexandre Bento Capela (Doctor) and Professor Henrique Amorim Almeida, it was decided to make a project work relating to the laser milling. The role of the technical equipment in laser micro technology is to perform a controllable action of the laser radiation on the material to be treated. In initiates a concrete technological process in areas of precisely controllable shape and size. The laser is the main unit of the equipment and it is characteristics determine to great extent the qualitative and quantitative parameters of the technological treatments. In this work, I had to follow the laser milling process parameters selection for process planning operations from start to finish, because it was important to have an understanding about what laser machining, micromachining, laser milling and laser material interaction are, then, about laser processing of different materials (mainly steel ) and the laser processing parameters (including surface hardness, surface roughness, surface friction, surface contact angle, tribology (the study of friction) etc.). During the process, I gained knowledge about the historical and conceptual framework of laser, the different parameters of a laser milling, machining processing of different material, also about problem solving methods of the same issues related titles. 1.2 Report Structure This work is structured as follows: Chapter 1 The first part is covered by presentation and description of project structure. 1 Chapter 2 This section is state of the art mainly related to laser beam machining, laser technology, laser assisted machining processes and micromachining technologies by entering connected topics. Chapter 3 3rd chapter referring to the experimental material which will be presented in this work, procedures and parameters, processes and also to the different equipments (Surface Hardness and Roughness Tester). Chapter 4 This chapter make reference to the experimental materials and procedures. The material Steel which used in this work is presented parameters and also be referred to the different equipments (Surface Roughness and Surface Hardness Tester). Chapter 5 Research quits with Discussion of results. Chapter 6 Final conclusion and considerations. 2 Chapter II 2. State of the Art Manufacturing, in its comprehensive sense, is the process of converting raw materials into products. Manufacturing also involves activities in which the manufacturing product, itself, is used to make other products. Examples could include large processes to shape sheet metal for appliances and car bodies, machinery to make fasteners, such as bolts and nuts, and sewing machines to make clothing. A nation s level of manufacturing activity is related directly to its economic health; generally, the higher the level of manufacturing activity in a country, the higher the standard of living of its people. [1] The world manufacturing is derived from the Latin manu factus, meaning made by hand. The word manufacture first appeared in 1567, and the word manufacturing appeared in The word product means something that is produced, and the words product and production often are used interchangeably. [1] Because a manufactured item typically has undergone a number of processes in which pieces of raw material have been turned into a useful product, it has a value-defined as monetary worth or marketable price. For example, as a raw material for ceramics, clay has some small value as mined. When the clay is made into the ceramic part of a spark plug, a vase, a cutting tool, or an electrical insulator, value is added the clay. [1] Manufacturing is generally a complex activity involving a wide variety of resourced and activities, such as the following: Product design Machinery and tooling Process planning Materials Purchasing Manufacturing Production control 3 Support services Marketing Sales Shipping Customer service It is essential that manufacturing activities be responsive to several demands and trends: 1. A product must fully meet design requirements, product specification, and standards. 2. A product must be manufactured by the most economical and environmentally friendly methods. 3. Quality must be built into the product at each stage, from design to assembly, rather than relying on quality testing after the product is manufactured. 4. In the highly competitive environment of today, production methods must be sufficiently flexible to respond to changing market demands, types of products, production rates, production quantities, and to provide on-time delivery to the customer. 5. Continuous developments in materials, production methods, and computer integration of both technological and managerial activities in a manufacturing organization must be evaluated constantly with a view to their appropriate, timely, and economical implementation. 6. Manufacturing activities must be viewed as a large system, all parts of which are interrelated to varying degrees. 7. The manufacturer must work with the customer for timely feedback for continuous product improvement. 8. Manufacturing organization constantly must strive for higher level of productivity, defined as the optimum use of all its resources such as materials, machines, energy, capital, labor and technology; output per employee per hour in all phases must be maximized. [1] 4 An extensive and continuously expanding variety of manufacturing processes are used to produce parts and there is usually more than one method of manufacturing a part from a given material. The broad categories of the methods for materials are as follows, referenced to the relevant part in this text and illustrated with examples for each: a) Casting: Expendable mould and permanent mould b) Forming and shaping: Rolling, forging, extrusion, drawing, sheet, forming, powder metallurgy and moulding. c) Machining: Turning, boring, drilling, milling, planning, shaping, broaching, and grinding, ultrasonic machining, chemical, electrical and electrochemical machining; and highenergy-beam machining. This category also including micromachining for producing ultraprecision parts. d) Joining: Welding, brazing, soldering, diffusion bonding, adhesive bonding and mechanical joining. e) Finishing: Honing, lapping, polishing, burnishing, deburring, surface treating, coating and plating. f) Nanofabrication: It is the most advanced technology and is capable of producing parts with dimensions at the nano level (one billionth); it typically involves processes such as etching techniques, electron-beams and laser-beams. Present application are in the fabrication of micro electromechanical system (MEMS) and extending to nano electromechanical systems (NEMS), which operate on the same scale as biological molecules. [1] Selection of particular manufacturing process or a sequence of processes depends not only on the shape to be produced but also on other factors pertaining to material properties. Brittle and hard materials cannot be shaped or formed easily, whereas they can be cast, machined or ground. Metals that are previously formed at room temperature become stronger and less ductile than they were before processing them, and thus will require higher forces and be less formable during secondary processing. [1] All machining processes discussed up to this point were characterized by the mechanical removal of material in the form of chips, even though chip formation may have been imperfect. There are numbers of processes that remove material by melting, evaporation, or chemical and/or 5 electrical action; collectively they are often denoted as nonconventional or nontraditional processes. Some of these processes are not really new but have gained wider industrial application primarily because of the demands set by the aerospace and electronic industries. As a group they are characterized by insensitivity to the hardness of the workpiece material, hence they are suitable parts from fully heat-treated materials, avoiding the problems of distortion and dimensional change that often accompany heat treatment. [2] Machining consists of several major types of material-removal processes: Cutting, typically involving single-point or multipoint cutting tools, each with a clearly defined shape. Abrasive processes, such a grinding and related processes. Advance machining processes utilizing electrical, chemical, laser, thermal, and hydrodynamic methods to accomplish this task. Machines on which these operations are performed are called machine tools. [1]. As in other manufacturing operations, it is important to view machining operations as a system, consisting of the Workpiece Cutting tool Machine tool Production personnel Machining cannot be carried our efficiently or economically and also meet stringent part specifications without a thorough knowledge of the interactions among these four elements. [1]. The machining processes describe in above involved material removal by mechanical means, by either chip formation, abrasion or micro chipping. However, there are
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