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Introduction to production processes


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Very important part department of the Mechanical Engineer.

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Introduction to production processes

  1. 1. IPE 331: Production Process 3.00 Credit Hours Prof. Dr. Shamsuddin Ahmed Room 210, GR Campus Where to Start? Humour without Malice 1. Ahmad was speaking to his friend and shared his happiness with him. So he said that he is fortunate to have been given two very special gifts in life. The friend was listening – there was a pause. He then asked: what are they Ahmad? Ahmad replied: one is a very good memory that God has given me. Ahmad paused again, and when his friend asked: what is the second one? Ahmad replied: Oh, wait a minute, I am trying to remember! 2. A man fell on the ground and soon after fell down again. He said to himself: “Had I known I was going to fall a second time, I would have not gotten up so soon.” On Education  “The goal of education is the advancement of knowledge and the dissemination of truth.” John F Kennedy  “The function of Education is to teach one to think intensively and to think critically. Intelligence plus Character that is the goal of true Education. - Dr. Martin Luther King, Jr.  “Educating the mind without educating the heart is no education at all.” - Aristotle  “Education is not the learning of facts, but the training of the mind to think.” - Alber Einstein  “There are two educations. One should teach us how to make a living and the other how to live.” - John Adams  “You can fool all the people some of the time, and some of the people all the time, but you cannot fool all the people all the time” - Abraham Lincoln  Seek knowledge from the cradle to the grave. He who leaves home in search of knowledge, walks in the path of God. -Prophet Muhammad (pbuh). “Who am I?”, “why am I here?”, “what is the purpose of existence?” What is my worldview? So, Let’s work for the welfare of mankind. Let’s collectively SAVE  ENERGY (ELECTRICITY etc.)  FOOD  PAPER/TREE  WATER  ANY OTHER RESOURCES
  2. 2. WASTE NOT ANYTHING FOR THE WELFARE OF SU, BANGLADESH AND MANKIND What is Engineering? Or, Who is an Engineer? Engineering is a profession in which the knowledge of mathematics and natural sciences gained by study, experience, and practice is applied with judgment to develop ways and means to utilize, economically, the material and forces of nature for the benefit of mankind (ABET). Engineering and Science Science is concerned with quest of basic knowledge. Engineering is concerned with the application of scientific knowledge to the solutions of problems and to the quest for better life. Basic science is known as “knowing science”, whereas engineering is known as “doing science”. However, the development of science and engineering often occur hand-in- hand. In some cases, a scientist and an engineer might be the same person. Engineers and other professionals  Engineers solve problems and use mathematics  Engineers analyze data  Engineer design systems. Design = analysis + synthesis Engineers use resources (materials, machines, men, money). They need to analyze lots of data and come up with (mostly) tangible solutions. Engineer comes from old French word in the form of verb (’ingenier) An engineer is one who seeks in his mind, who sets his mental power in action, in order to discover or devise some means of succeeding in a difficult task he may have to perform. To be human is to be an engineer. Engineer => Art + Artifacts => Design + how it goes about Key words for an engineer: change, resources, best, and uncertainty. Engineering method Strategy for causing the best change in a poorly understood situation within the available resources.
  3. 3. Engineering process The basic steps are as below: 1) Problem symptom (need expression) 2) Problem definition 3) Statement of the desired outcome 4) Analysis/experimentation 5) Synthesis of alternative solution 6) Decision (one alternative solution) 7) Solution (system or method) What is Mechanical Engineering? Mechanical Engineering is - If it needs engineering but it doesn’t involve electrons, chemical reactions, arrangement of molecules, life forms, isn’t a structure (building/bridge/dam) and doesn’t fly, a mechanical engineer will take care of it… but if it does involve electrons, chemical reactions, arrangement of molecules, life forms, is a structure or does fly, mechanical engineers may handle it anyway Although every engineering faculty member in every engineering department will claim that his/her field is the broadest engineering discipline, in the case of Mechanical Engineering that’s actually true because the core material permeates all engineering systems (fluid mechanics, solid mechanics, heat transfer, control systems, etc.) Mechanical engineering is one of the oldest engineering fields but in the past 20 years has undergone a rather remarkable transformation as a result of a number of new technological developments. Define manufacturing engineering. Why is it important today? Manufacturing Engineering is the process of designing a product(s) and production process(es) to produce the product(s). Manufacturing is an industrial activity to transform (raw) materials and information into goods/products, mainly by machinery, normally on large scale and with division of labor, for the welfare and satisfaction of human needs. Manufacturing is now the primary wealth-generating activity for a nation. It is the backbone of an industrial nation. Level of manufacturing is related to economic health and standard of living of the people. It has significant role in national development – economic development and employment. Service sector is enhanced by increasing manufacturing activity. IPE 331: Production Process 3.00 Credit Hours Syllabus: Selection of machining. Casting: sand, die, centrifugal and other types of casting, casting design and casting defects Chip less metal forming process: different types of hot and cold working processes. Welding arc, gas, TIG, MIG, resistance,
  4. 4. thermite, and special types, Brazing and soldering. Tool geometry and chip formation processes. Metal removing processes: turning, drilling, shaping, planning, milling, broaching, grinding, precision and non-precision finishing processes. Plastic, ceramic and glass product manufacturing processes. Manufacturing vs production Manufacturing is a process of converting raw material in to finished product by using various processes, machines and energy. It is a narrow term. Production is a process of converting inputs in to outputs. It is a broader term. Every type of manufacturing can be production, but every production is not a manufacturing. Manufacturing encompasses –  Design of the product  Selection of raw materials  Sequence of processes to produce/manufacture the product. Basic manufacturing processes – Casting: expandable molding and permanent molding – Deformation - Forming and shaping: rolling, forging, extrusion, drawing, sheet forming, powder metallurgy molding – Machining: turning, boring, drilling, milling, planing, shaping, broaching, grinding, ultrasonic machining; chemical, electrical, and electrochemical machining and high energy electron beam machining – Joining: welding, brazing, soldering, diffusion bonding, adhesive bonding and mechanical joining – Micro and nano manufacturing: surface micromachining, dry and wet etching, and electroforming – Finishing: honing, lapping, polishing, burnishing, deburring, surface treating, coating and plating Factors affecting process selection • Component/part shape • Materials characteristics – castability, formability, machinability, weldability, etc. • Part size and dimensional accuracy
  5. 5. • Volume of production  Manufacturing and operational cost Process manufacturing Process manufacturing is the production of goods that are typically produced in bulk quantities, as opposed to discrete and countable units. Process manufacturing industries include chemicals, food and beverage, gasoline, paint and pharmaceutical. Fabrication Fabrication is an industrial term that refers to the manipulation of raw materials (such as steel) for the making of machines and structures. Steel and other metals are cut and shaped during the fabrication process. Fabrication is a very hands-on part of the manufacturing process. Sheet metal fabrication is using sheet metal to build metal machines and structures. It can be a complex process involving many different professionals. Businesses that specialize in sheet metal fabrication are commonly referred to as fabrication shops, or fab shops for short. Materials used in today’s manufacturing  Ferrous metals: carbon steels, alloy steels, stainless steels, and tool and die steels  Nonferrous metals and alloys: Al, Mg, Cu, Ni, superalloys, Ti, refractory metals (Mb, Nb, W, beryllium, Zr, low melting alloys (lead, zinc and tin), and precious metals  Plastics: Thermosets, thermoplastics, and elastomers  Glass and Ceramics: Glass ceramics, glasses, graphite, and diamond  Composites: Reinforced plastics, metal-matrix and ceramics-matrix composites, and honeycomb structures  Nanomaterials, shape-memory alloys, metal foams, amorphous alloys, super conductors and Semiconductors Material substitution Material properties: mechanical, physical, chemical, manufacturing Manufacturing System Designs Job Shop Production  Small quantities of products  Large variety of products  Products move through the shop to various machines  General-purpose machines
  6. 6. Flow Shop o Larger quantities of products o Production line o Special purpose machines Linked-Cell Shop o Manufacturing and subassembly cells connected to final assembly o Lean production system o One piece flow system
  7. 7. Project Shop o Product being manufactured cannot be easily moved during production. o Production processes are brought to the product. o Examples: Bridges, ships, large airplanes, locomotives, large machinery. Continuous Process o Large plants o Utilized in the manufacture of liquids, oils, gases, and powders
  8. 8. Casting and Foundry Processes  In a step, raw materials are transformed into a desirable shape  Parts require finishing processes  Excess material is recyclable Basic Casting Process  A mold is created – A cavity that holds the molten material in a desired shape until it is solidified o Multiple-use mold o Single-use molds  Material is heated to a specified temperature  Molten material is poured into a mold cavity  Molten material solidifies into the shape of the cavity  Casting or mold is removed  Casting is cleaned, finished, and inspected
  9. 9. Deformation process Utilizing property of metals, that is ability to flow plastically in the solid state without deteriorating their properties. Application of high pressure to move material to desired shape with negligible wastage. Expensive tools and machines are needed, so large production volume is important. Forming and Metalworking Processes  Utilizes material that has been cast  Modify the shape, size, and physical properties of the material  Hot and cold forming Rolling – Material passes through a series of rollers, reducing its thickness with each pass Forging – Material is shaped by the controlled application of force (blacksmith) Extrusion – Material is compressed and forced through a die to produce a uniformed cross section
  10. 10. Wire, rod, and tube drawing – Material is pulled through a die to produce a uniformed cross section Cold forming and forging – Slugs of material are squeezed into dies Machining Processes Controlled removal of material from a part to create a specific shape or surface finish Cutting element is used Movement must exist between the part and cutting element
  11. 11. Turning Processes  Operations that create cylindrical parts  Work piece rotates as cutting tool is fed into the work Lathes and turning centers Processes include: Straight, taper, contour turning, facing, forming, necking, parting, boring, threading, and knurling
  12. 12. Milling Process  Operations that create flat or curved surfaces by progressively removing material  Cutting tools rotate as the work piece is secured and fed into the tool Mills – Vertical and horizontal Processes include: Surfacing, shaping, forming, slotting, T-slotting, angle, straddle, dovetailing, and slab milling Drilling process  Operations that create holes  Cutting tools rotate and are fed into nonmoving secured work pieces
  13. 13. Drilling and boring machines Processes include: Drilling, counter drilling, step drilling, boring, counter boring, countersinking, reaming, spot facing, and tapping Shearing processes  Operations that break unwanted material away from the part  A material is placed between a stationary and movable surface. The movable surface (blade, die, or punch) applies a force to the part that shears away the unwanted material.  Automated hole punch, squaring shear, and rotary cutter  Processes include: Shearing, blanking, cutoff, and parting; punching, perforating, and slotting; notching, lacing, and trimming Abrasive machining processes  Operations in which small particles of materials (abrasives) remove small chips of material upon contact  Drum, disc, and belt sanders; surface, vertical and horizontal spindle; disc grinders; media blaster; tumblers
  14. 14. Thermal and Chemical Processes  Operations that cut and shape materials through chemical means  No mechanical force is used  Electrical discharge, electrochemical, chemical, laser, electron beam, flame cutting, and plasma-arc cutting  Processes include: Grinding, sawing, cutting, machining, milling, blanking, and etching Heat Treating Processes  Controlled heating and cooling of a material to alter its properties while maintaining its shape  Properties include: Strength, toughness, machinability, wear resistance, and corrosion resistance  90% of heat treating is preformed on steel and other ferrous metals  To aid in the manufacturing process, materials can be treated to be weak and ductile and then can be re-treated to provide high strength.  Can also occur incidentally during the manufacturing process Joining and Assembly Processes  Can you think of a product with only one part?  Most products consist of multiple parts that are assembled to form a finished product.  Typical assembly processes include: Mechanical fastening; soldering and brazing, welding; adhesive bonding Mechanical Fastening  Use physical force to hold parts together  Mechanical fasteners or part design
  15. 15.  Screws, bolts, nails, rivets, cotter pins, retaining clips, and edge design Welding  Operations that use heat, pressure, or both to permanently join parts  Gas, arc, stud, spot, forge, roll laminating, resistance, and induction welding Adhesive bonding Bonding of adjoining surfaces by filling the gap between each surface with a bonding material Glue, cement, thermoplastic, thermosetting, and elastomers
  16. 16. Soldering and Brazing Operation in which metal surfaces are bonded together by an alloy Heated molten alloy flows between the adjoining surfaces When the heat is removed, the molten metal solidifies and the metal surfaces are bonded. Rapid prototyping Additive process  Parts are produced directly from software applications  Common rapid prototyping systems include: stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), laminated object manufacturing (LOM), digital light processing (DLP).  Finished parts can be field tested depending upon building material  Created parts can be used to create a mold  Modifications to design can be implemented quickly.
  17. 17. Other Manufacturing Processes  Testing  Transportation  Material handling  Packaging Material-Specific Manufacturing Processes  Plastic Processes  Ceramic Processes
  18. 18. Plastics Manufacturing Processes  A rotating screw forces plastic through a heating chamber and then through a heated die  Produces long plastic parts with uniform cross sections.  Injection Molding on Plastic Mfg process  Heated plastic is forced by a movable plunger through a nozzle and then into a mold. The material fills the mold and then is cooled.  Most widely used high-volume production process.
  19. 19. Casting (Plastics Manufacturing Processes) Plastic is melted and poured into a mold – No pressure or fillers are required. Rotational Molding A closed mold is filled with a predetermined amount of plastic. The mold is heated, rotated, and then cooled to create a hollow plastic object with uniform wall thickness. Blow Molding A solid bottom hollow tube is placed between two mold halves and heated. The heated tube is then expanded into the sides of the mold with compressed air. Thermoforming Plastic sheets are heated over an open mold to a working temperature. Once workable, a vacuum is applied to the mold, forcing the plastic sheet to take the shape of the mold. Reaction Molding Liquid reactants are mixed and then pressurized into a mold. No heat is needed. Curing time is typically less than 1 minute. Ceramic Manufacturing Processes Two distinct classes of materials and processes exist.
  20. 20. Glass is heated to a molten state, shaped by viscous flow, and then cooled to produce a solid. Crystalline Ceramics Material is shaped and then heated to produce a permanent solid. Manufacturing Importance - Typical product cost breakdown