Manufacturing Processes

1
WHAT IS MANUFACTURING
Manufacturing is the process of converting raw
materials into products. It encompasses the
design and manufacturing of goods using various
production methods and techniques. The word
manufacturing is derived from the Latin manu
factus meaning made by hand. Modern
manufacturing involves making products from raw
materials by various processes machinery and
operations following a well-organized plan for
each step.
2
Type of Course

• Manufacturing is an integration course
• It integrates your knowledge of
• Materials
• Nature of materials
• Mechanical properties
• Flow properties
• Stress strain behavior
• Statics
• Forces torques pressures vectors
• Resolution of forces/vectors
• Phase changes/crystal growth
• Thermodynamics
• Specific heat
• Latent heat
• Heat transfer
• Fluid flow statistics control etc

3
Examples of Knowledge Integration

• Casting
• Fluid flow
• Heat Transfer
• Phase changes
• Crystal growth in pure metals and alloys
• Rolling
• Vector forces
• Relationships among force power and energy
• Effect of deformation on crystal structure
• Effect of temperature on microstructure (heat
  treating)
• Machine dynamics

4
Why is traditional engineering so expensive

• The typical cost for each change made during the
  development of a major product
• When changes are made
  Cost
• During Design
  
  1000
• During Design Testing
  10000
• During Process Planning
  100000
• During Test Production
  1000000
• During Final Production
  10000000

5
(No Transcript)
6
(No Transcript)
7
The basic goals of CE are

• to minimize product design and engineering
  changes.
• to minimize time and cost involved in taking
  product from design concept to production and
  introduction of the product into the marketplace.
• Direct Engineering
• utilizes a database representing the engineering
  logic used in the design of each part of a
  product.
• If a design modification is made on a part DE
  will determine the manufacturing consequences of
  that change.
• In order to implement CE it should be provided
• the full support of upper management
• a multifunctional and interactive work team
• utilization of all available technologies

8

• Product design involves preparing analytical and
  physical models of the product as an aid to
  analyze factors such as
• forces
• stresses
• deflections
• optimal part shape

• Computer-aided design engineering and
  manufacturing simplifies construction and
  analyses of analytical models.
• On the basis of these models the product
  designer selects and specifies the final shape
  and dimensions of the product its dimensional
  accuracy and surface finish and the materials to
  be used.

9

• A powerful and effective tool is COMPUTER
  SIMULATION in evaluating the performance of the
  product and planning the manufacturing system to
  produce it.
• Computer simulation helps in
• early detection of design flaws
• identifying possible problems in a particular
  production system
• optimizing manufacturing lines for minimum
  product cost

Computer simulation predicting tool performance
10
Overview of the Manufacturing Processes

• The final shape of the manufactured component can
  be achieved by
• Changing the shape of the raw stock without
  adding material to it or taking material away
  from it.
• Metal forming processes Rolling extrusion
  forging drawing sheet metal forming
• Obtaining the required shape by adding metal or
  joining two metallic parts together
• Welding brazing metal deposition
• Molding molten or particulate metal into a cavity
  that has the same shape as the final product
• Casting powder deposition
• Removing portions from the stock material to
  obtain the final shape
• turning milling drilling etc.

11
Factors involved in the processes

• Material Removal
• Shear stress strain behavior
• Vector forces
• Relationships among force power and energy and
  shearing energy
• Machine dynamics
• Thermodynamics and material expansion
• Powder Processing for metals ceramics and
  plastics
• Surface science
• Thermodynamics
• Effect of heat on microstructure
• Sintering
• Flow and rheology of powders

12
Fundamentals of Manufacturing Concepts

• The ability to create shapes components and
  assembled products relies on several physical
  phenomena
• The liquid to solid phase transformation
• Create the required shape in the liquid form then
  solidify
• The ability of certain materials to flow under
  stresses greater than some limit
• soften the material by heating it then shape it
• The ability of powders to flow like liquid and
  for powders to sinter and densify under heat
  and/or pressure
• Useful for brittle materials
• Additive methods
• The method chosen depends on the material and the
  required properties.

13

• Liquid to solid phase transformation
• Create a negative mold of the same shape
• Pour the liquid material in the mold
• Solidify by
• extracting heat or liquid (e.g. water)
• reactions heat induced photon induced or by
  reagents
• Remove the solid part from the mold
• Casting conditions determine the properties

14

• Material Flow
• Most metals and many plastics flow when stress
  exceeds the yield stress
• The stress-strain curve has three regions
  elastic yield stress and flow regime.
• Flow regime - mechanical energy transformed into
  deformation and heat

• Stress/strain conditions
• Pure Compressive
• die forging
• Pure Tensile
• drawing
• Pure Shear
• cutting machining turning

15

• Combined Stress States
• Rolling
• Mostly compressive with some shear
• Forging
• Extremely complex stress states
• Extrusion
• Combination of high compressive and shear
  stresses
• Bending
• Mostly shear with tensile and compressive
  components
• Stretching with bending
• Mostly shear with only tensile components
• Machining
• Highly complex stress combination with high
  levels of shear causing fracture in a controlled
  manner

16

• Powder Processing
• Takes advantage of the ability of powders to flow
  like a liquid and fill complex shapes
• can be dry or slurry
• can be compacted by pressure or extraction of
  liquid from the slurry
• this process forms a green body which is pliable
  and weak
• heating to high temperatures causes the powder
  particles to sinter together for a strong nearly
  100 dense product

17

• Tolerances
• impossible to obtain the desired nominal
  dimension when processing a workpiece
• caused by
• inaccuracies inherent in the machine tool
• elastic deformation of the workpiece and/or
  fixture
• temperature effects during processing
• skill of the operator
• establish a permissible degree of inaccuracy with
  respect to the nominal dimension that will not
  affect the proper functioning of the manufactured
  part
• the nominal dimension is referred to as the the
  basic size of the part

18

• the deviations from the basic size to each side
  determine the high and low limits
• the difference between these two limits of size
  is called the tolerance
• The International Standardization Organization
  (ISO)

• the magnitude of the tolerance is dependent upon
  the basic size and is designated by an
  alphanumeric symbol called the grade
• there are 18 standard grades of tolerance in the
  ISO system

19

• Fits
• the relationship between the dimensions of the
  mating surfaces must be specified
• this determines the degree of tightness or
  freedom for relative motion between the mating
  surfaces
• clearance fit the upper limit of the shaft is
  always smaller than the lower limit of the mating
  hole

• interference fit the lower limit of the shaft
  is always larger than the upper limit of the hole
• transition fit is an intermediate fit

20

• Interchangeability
• means that identical parts must be able to
  replace each other without the need for any
  fitting operation
• it is achieved by establishing a permissible
  tolerance beyond which any further deviation
  from the nominal dimension of the part is not
  allowed
• standardization limits the diversity and total
  number of varieties to a definite range of
  standard dimensions
• e.g. For wires and sheets the sheet thickness
  is limited to only 45 (in US standards)

21

• The Production Turn
• The main goal of a manufacturing project is to
  make a profit

22
Product Life Cycle
23
Technology Development Cycle

• A new technology emerges as a result of active
  RD and is then employed in the design and
  manufacturing of several different products.
• Technology is concerned with the industrial and
  everyday applications of the results of the
  theoretical and experimental studies that are
  referred to as engineering

24
(No Transcript)
25
Rapid Prototyping

• Rapid prototyping relies on CAD/CAM and various
  manufacturing techniques to produce prototypes in
  the form of a solid physical model of a part
  rapidly and at low cost.
• These techniques can be used for low-volume
  economical production of parts.
• Tests on prototypes must be designed to simulate
  as closely as possible the conditions under
  which the product is to be used.

26

• Computer-aided engineering techniques are now
  capable of comprehensively and rapidly performing
  such simulations.
• After this phase has been completed appropriate
  process plans manufacturing methods equipment
  and tooling are selected with the cooperation of
  manufacturing engineers process planner and all
  others involved in production.

27
Design for Manufacturing Assembly Disassembly
and Service

• Design for manufacturing (DFM) is a comprehensive
  approach to production of goods and integrates
  the design process with materials manufacturing
  methods process planning assembly testing and
  quality assurance.
• Designers should acquire a fundamental
  understanding of the characteristics
  capabilities and limitations of materials
  manufacturing processes and related operations
  machinery and equipment.
• Expert system expedites the traditional iterative
  process in design optimization.

28
(No Transcript)
29
Selecting Materials
30
(No Transcript)
31
Properties of Materials

• Mechanical Properties
• strength
• toughness
• ductility
• hardness
• elasticity
• fatigue
• creep
• Physical Properties
• density
• specific heat
• conductivity
• melting point
• electric and magnetic properties

32

• Chemical Properties
• oxidation
• corrosion
• general degredation
• toxicity
• flammability
• Manufacturing properties of materials determine
  whether they can be cast formed shaped
  machined welded or heat-treated with relative
  ease.
• Another important consideration is that the
  methods used to process materials to the desired
  shapes ma adversely affect the products final
  properties service life and cost.

33

• Cost and Availability
• The economic aspects of material selection are as
  important as the technological considerations of
  properties and characteristics of materials.
• Appearance Service Life and Recycling
• color
• feel
• surface texture
• time and service dependent phenomena such as
  wear fatigue creep and dimensional stability
  are also important.
• Compatibility of materials

34
Selecting Manufacturing Processes

• There is usually more than one method of
  manufacturing a part from a given material.
• Casting expandable mold and permanent mold
• Forming and Shaping rolling extrusion
  drawing sheet forming powder metallurgy and
  molding.
• Machining turning drilling milling planning
  shaping broaching grinding ultrasonic
  machining chemical electrical and
  electrochemical machining and high-energy beam
  machining.
• Joining welding brazing soldering diffusion
  bonding adhesive bonding and mechanical
  joining.
• Finishing Operations honing lapping
  polishing burnishing deburring surface
  treating coating and plating.

35
(No Transcript)
36
Dimensional and Surface Finish Consideration

• Size thickness and shape complexity of the part
  have a major bearing on the process selected to
  produce it.
• Flat parts with thin cross-sections cannot be
  cast properly. Complex parts cannot be formed
  easily and economically.
• Tolerances and surface finish obtained in
  hot-working operations cannot be as fine as those
  obtained in cold-working operations. Dimensional
  changes warpage and surface oxidation occur
  during processing at elevated temperatures.

37

• The size and shape of manufactured parts cary
  widely.
• Nanotechnology and nanofabrication
• Ultraprecision manufacturing techniques and
  machinery is coming into more common use. Highly
  sophisticated techniques such as molecular-beam
  epitaxy and scanning-tunneling engineering will
  be implemented to obtain accuracies on the order
  of the atomic lattice

38
Operational and Manufacturing Cost Considerations

• the design and cost of tooling the lead time
  required to begins production and the effect of
  workpiece materials on tool and die life
• availability of machines and equipment and
  operating experience
• environmental and safety implications
• the safe use of machinery

39
Net-shape Manufacturing

• The parts are made as close to the final desired
  dimensions tolerances and specifications as
  possible.
• Typical examples are near-net shape forging and
  casting of parts stamped sheet-metal parts
  components made by powder metallurgy techniques
  and injection molding of plastics.

40
Computer Integrated Manufacturing

• The major goals of automation in manufacturing
  facilities are
• to integrate carious operations
• to improve productivity
• increase product quality and uniformity
• minimize cycle times
• reduce labor costs
• Computers are used for
• optimization of manufacturing processes
• material handling
• assembly
• automated inspection and testing of products.

41
(No Transcript)
42
Machine Control Systems

• Numerical Control (NC) of machines is a method of
  controlling the movements of machine components
  by direct insertion of coded instructions in the
  form of numerical data.
• In adaptive control (AC) process parameters are
  adjusted automatically to optimize production
  rate and product quality and minimize cost.
  Parameters such as forces temperatures surface
  finish and dimensions of the part are monitored
  constantly.

43
Computer Technology

• Computers allow us to integrate virtually all
  phases of manufacturing operations which consist
  of various technical as well as managerial
  activities.
• Computer-integrated Manufacturing (CIM) is
  characterized with
• responsiveness to rapid changes in market demand
  product modification and shorter product cycles
• high quality products at low cost
• better use of materials machinery and
  personnel and reduced inventory
• better control of production and management of
  the total manufacturing operation

44

• Computer-aided Design (CAD) allows the designer
  to conceptualize objects more easily without
  having to make costly illustrations models or
  prototypes.
• Computer-aided Engineering provides
• simulation analyses and testing of the
  performance of structures subjected to static or
  fluctuating loads and temperatures.
• Computer-aided Manufacturing (CAM) involves all
  phases of manufacturing by utilizing and
  processing further the large amount of
  information on materials and processes collected
  and stored in the organizations database.
• Some of the tasks are programming numerical
  control of machines programming robots for
  material handling designing tools dies and
  fixtures and maintaining quality control.

45

• Computer-aided Process Planning (CAPP) is capable
  of improving productivity in a plant by
  optimizing process plans reducing planning
  costs and improving the consistence of product
  quality and reliability. Functions such as cost
  estimating and time required to perform a certain
  operation can also be incorporated into the
  system.
• Group Technology and Cellular Manufacturing (CM)
• The concept of group manufacturing is that parts
  can be grouped and produced by classifying them
  according to similarities in design and
  manufacturing processes. In this way part
  design and process plans can be standardized and
  families of parts can be produced efficiently and
  economically.

46
Quality Assurance and Total Quality Management

• Traditionally quality assurance has been
  obtained by inspecting parts after they have been
  manufactured.
• Quality must be built into a product from the
  design stage through all subsequent stages of
  manufacture and assembly.
• We control processes not products.
• Product integrity is a term that can be used to
  define the degree to which a product
• is suitable for its intended purpose
• fills a real market need
• functions reliably during its life expectancy
• can be maintained with relative ease.

47

• Total quality management (TQM)
• becomes the responsibility of everyone involved
  in designing and manufacturing a product
• prevents defects from occurring rather than
  detecting defective products
• Important developments in quality assurance
  include the implementation of design of
  experiment a technique in which the factors
  involved in a manufacturing process and their
  interactions are studied simultaneously.
• ISO 9000 series on quality management and quality
  assurance standards
• this is a quality process certification not a
  product certification
• It is becoming the world standard for quality

48
Global Competitiveness and Manufacturing Costs

• Typically manufacturing costs represent about
  40 of a products selling price
• design principles for economic production are
• the design should be as simple as possible to
  manufacture assemble disassemble and recycle
• materials should be chosen for their appropriate
  manufacturing characteristics
• dimensional accuracy and surface finish specified
  should be as broad as permissible
• because they can add significantly to cost
  secondary and finishing processes should be
  avoided or minimized
• The total cost of manufacturing a product
  consists of
• materials
• tooling
• labor
• fixed and capital costs

49
Environmental Concerns

• Discarded per year in the US
• 9 million passenger cars
• 285 million tires
• more than 5 billion kilograms of plastic products
• metalworking fluids (lubricants coolants
  solvents etc.)
• by-products sand with additives for casting
  water oild and other fluids from heat-treating
  facilities and plating operations slag from
  foundries and welding operations scrap of all
  kinds
• 800000 metric tons of old TV sets radios and
  computer equipment are discarded in Germany each
  year.

50

• Certain guidelines can be followed
• reducing waste of materials at their source by
  refinements in product design and reducing the
  amount of materials used
• conducting research and development of
  manufacturing technologies
• reducing the use of hazardous materials in
  products and processes
• ensuring proper handling and disposal of all
  waste
• making improvements in recycling waste
  treatment and reuse of materials
• Design for the environment
• Design for recycling

51
Flexible Manufacturing Systems (FMS)

• FMS integrate manufacturing cells into a large
  unit containing industrial robots and automated
  guided vehicles (AGVs) serving several machines
  all interfaced with a central computer.

52

• Just-in-Time Production (JIT) is a concept in
  manufacturing in which supplies are delivered
  just in time to be used parts are produced just
  in time to be made into subassemblies and
  assemblies and products are finished just in time
  to be sold.
• Artificial Intelligence (AI) involves the use of
  machines and computers to replace human
  intelligence
• expert systems - intelligent computer programs
• artificial neural networks (ANN) simulate the
  thought processes of the human brain.
• ANN have the capability of modeling and
  simulating production facilities monitoring and
  controlling manufacturing processes diagnosing
  problems in machine performance conducting
  financial planning and managing a companys
  manufacturing strategy.
• Factory of the future in which production takes
  place with little or no direct human intervention.

53
Lean Production and Agile Manufacturing

• Lean production involves major assessment of each
  of the companys activities
• efficiency and effectiveness of each operation
• necessity of retaining operations and managers
• efficiency of the machinery and equipment used
  while maintaining quality
• number of personnel involved in each operation
• reduce cost and waste of each activity
• requires a fundamental change in corporate
  culture
• Agile manufacturing is ensuring flexibility in
  the manufacturing enterprise so it can quickly
  respond to changes in product variety demand
  and customer needs.
• Lean Flexible Agile

54
Product Liability

• Designing and manufacturing safe products is an
  important and integral part of a manufacturers
  responsibilities.
• Examples that could involve liability are
• a grinding wheel that shatters and blinds a
  worker
• a cable that snaps allowing a platform to drop
• brakes that become inoperative due to failure of
  one component
• machines with no guards or inappropriate ones
• electric or pneumatic tools without proper
  warnings
• Human factors engineering and ergonomic
  considerations are important aspects of the
  design and manufacture of safe products.

55
Organization for Manufacture

• Complex interactions among the carious factors
  involved in manufacturing - materials machines
  people information power and capital -
  requires the proper coordination and
  administration of diverse functions.
• Responsibilities of manufacturing engineers
• Plan the manufacture of a product and processes
  to be utilized
• identify the machines equipment tooling and
  personnel needed to carry out the plan
• interact with design and materials engineers to
  optimize productivity and minimized production
  costs
• Cooperate with industrial engineers when planning
  plant floor activities such as plant layout
  machine arrangement material handling equipment
  time-and-motion study production method
  analysis production planning and scheduling and
  maintenance.

56

• Manufacturing engineers in cooperation with
  industrial engineers also are responsible for
  evaluating new technologies their applications
  and how they can be implemented.