Introduction to Manufacturing Processes

Products and Manufacturing

  • Product Creation Cycle

    • Design → Material Selection → Process Selection → Manufacture → Inspection → Feedback

  • Typical Cost Breakdown

    • Manufacturing cost - 40%

    • Admin, sales, marketing - 25%]

    • Profit - 20%

    • Engineering - 15%

Manufacturing Processes

  • A sequence of operations and processes designed to create a specific product

  • The process of turning materials into a product

Engineers in Manufacturing

  • Manufacturing Engineer

    • Select and coordinate specific processes and equipment

  • Industrial Engineer

    • Responsible for the manufacturing system and design

  • Materials Engineer

    • Develop and select materials based on desired material properties and manufacturing processes

Manufacturing System Designs

  • Job Shop

    • Small quantities of products

    • Large variety of products

    • Products move through the shop to various machines

    • General-purpose machines

  • Flow Shop

    • Larger quantities of products

    • Production line

    • Special purpose machines

  • Linked-Cell Shop

    • Manufacturing and subassembly cells connected to final assembly

    • Lean production system

    • One piece flow system

  • Project Shop

    • Product being manufactured cannot be easily moved during production

    • Production processes are brought to the product

    • EX: Bridges, ships, large airplanes, locomotives, large machinery

Casting and Foundry Processes

  • In one 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

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 due to produce a uniformed cross section

  • Wire, rode, 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 be exist between the part and cutting element

  • Turning Processes

    • Operations that create cylindrical parts

    • Work piece rotates as cutting tool is fed into the work

  • Turning

  • Parting

  • Facing

  • Boring

  • Knurling

Milling Processes

  • Operations that create flat or curved surfaces by progressively removing material

  • Cutting tools rotate as the work pieces is secured and fed into the tool

  • Mills - vertical and horizontal

  • Processes include surfacing, shaping, forming, slotting, T-slotting, angle, straddle, dovetailing, slab milling

Drilling Processes

  • Operations that create holes

  • Cutting tools rotate and are fed into nonmoving secured work pieces

  • Drilling and boring machines

  • Processes include drilling, counter drilling, step drilling, boring, counter boring, countersinking, reaming, spot facing, tapping

Shearing Processes

  • Operations that break unwanted material away from the part

  • A material is placed between a stationary and moveable surface

  • The moveable surface (blade, die, punch) applies a force to the part that shears away the unwanted material

  • Automated hole punch, squaring shear, rotary cutter

  • Processes include shearing, blanking, cutoff and parting, punching, perforating, and slotting; notching, lacing, 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

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 the material to alter its properties while maintaining its shape

  • Properties include strength, toughness, machinability, wear resistance, and corrosion resistance

  • 90% of heat treating is performed 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

  • 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

  • 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, elastomers

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

  • 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

Other Manufacturing Processes

  • Testing

  • Transportation

  • Material Handling

  • Packaging

Plastics Manufacturing Processes

Extrusion

  • A rotating screw forced plastic through a heating chamber and then through a heated die

  • Produced long plastic parts with uniform cross sections

Injection

  • Heated plastic is forced by a moveable plunger through a nozzle and then into a mold

  • Material fills the mold and then is cooled

  • Most widely used high-volume production process

Casting

  • 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

  • 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

  • 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

  • Glass is heated to a molten state, shaped by viscous flow, then cooled to produce a solid

Crystalline Ceramics

  • Material is shaped and then heated to produce a permanent solid