Materials Technology

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Materials Technology
for Drafting, Construction, and Manufacturing
Seth Bates, Doctor of Shop Materials and
Manufacturing San Jose State University
sbates_at_sjsu.edu / 408 924-3227 This presentation
is available for download at http//www.citea.org/
resources.htm
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What is Materials Technology?

• Materials ScienceMatSci is focused on the
  chemistry and microstructure of materials.
  Typical background will be in chemistry. It
  involves the study of the chemical and physical
  principles underlying the behavior of materials,
  and the development of new materials
• Materials Engineering MatEngr is between
  MatSci and MatTech. It is fully engaged with the
  theory of why materials behave as they do, but is
  more applications oriented than MatSci.
  Typically at least one full each year of physical
  and organic chemistry is required. The study of
  how materials are designed and implemented
• Materials TechnologyMatTech is very practical
  and is oriented to the solution of production
  problems. Usually not calculus-based. It
  consists of the analysis of material needs,
  selection of materials to match product and
  process requirements, and implementation of
  materials testing and standards

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Sub-Categories of Materials

• Each family includes subsets. For example
• Ferrous metalsstainless, tool steels, cast
  steels, cast irons, wrought irons
• Non-ferrous metalsThis is a huge catch-bin of
  metals including silver, aluminum, titanium,
  copper, nickel, and many others. Any metal in
  which the primary alloy element is not Iron.
• CeramicsTechnical ceramics, stoneware, white
  ware, porcelain
• PlasticsThermoplastics (_at_15-20 general types),
  Thermosets (_at_ 8-12 general types), memory,
  elastomers, etc. Total _at_20,000 types
• CompositesMatrix composites, structural
  composites. There is a misimpression that
  composites are all about plastics. There are
  also metal matrix composites. Cement is a
  composite of concrete and aggregate, woods are
  grouped today under composites, since they are a
  naturally occurring group of materials that meet
  the definition of a composite

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Components of Materials Tech

• There are several major divisions to the field of
  MatTech
• Materials principles understanding the
  microstructure of typical materials and how that
  relates to material behavior
• Materials testing learning about common methods
  of test of materials including the tensile and
  other mechanical tests, but also a range of less
  obvious methods such as water absorption,
  flammability, electrical resistance, UV and
  environmental resistance, and much more.
• Materials selection learning to apply simple
  principles for choosing a material to make a part
  or product from.

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Who Thinks Materials are important?

• Every college of engineering in the world
  provides some basic study of materials
• Many technical schools.
• Most industrial technology programs in the U.S.

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• From the Don Bosco Technical Institute website
• Materials Science has entered what is being
  called the AGE of Superstuffan age of exciting
  new discoveries and applications involving
  traditional metals and newer plastics, ceramics,
  and composites. Materials scientists and
  engineers design and create the materials that
  make up our modern world. The study of Materials
  Science involves understanding why materials
  behave the way they do and how they can be
  manipulated into new and more useful forms.
  Understanding how an aluminum alloy can be made
  strong and heat-resistant enough to use as an
  automobile engine block, reducing fuel
  consumption and reaping environmental benefits
  or how a plastic can be used to make a
  biocompatible interface between an ear-implant
  and neural tissue are examples of the advances in
  Materials Science. Materials Science aims to
  understand the relationship between the
  composition and structure of materials, in order
  to predict and control their properties. It
  brings together in a unified discipline the
  developments in physical metallurgy, polymeric
  chemistry, ceramics, composites, and the physics
  and chemistry of solids.
• We all depend and rely on materials for every
  aspect of our lives. From the homes we live in,
  to the cars we drive from the places we work, to
  the things we buy from agriculture to space,
  cars, planes, boats, sports, and medicine, we use
  materials everyday. Materials Science is at the
  forefront of tomorrow because all other
  technologies depend on it.
• The Materials Science department provides
  students with a broad exposure to the theory,
  testing and evaluation of metallic and
  non-metallic systems. While in the Materials
  Science program, you will study various
  characteristics of metals, polymers, and
  ceramics. Among those characteristics are their
  structure and a variety of physical, chemical,
  and mechanical properties. You will learn and
  develop the necessary skills in technology
  courses with actual hands-on laboratory sessions.
  You will work with x-rays, microscopes, materials
  testing equipment, welding and foundry
  laboratories.
• If you find these prospects exciting, maybe you
  should consider preparing for a future in
  Materials Science. Graduates of the Materials
  Science Department can pursue a college degree in
  various fields such as engineering, technology,
  science, medicine and product liability law.
  Also, the student may choose to enter industry
  directly bringing with them strong laboratory
  skills which they will be able to apply to any
  engineering or science program.
• Download Materials Science Brochure

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Categories of Materials

• Modern materials tech divides materials into
  broad families
• Ferrous, or iron-based metals
• Non-ferrous metals
• Ceramics
• Plastics
• Composites
• Woods are grouped today under composites, since
  they are a naturally occurring group of materials
  that meet the definition of a composite
• There are a number of sub-groups for each of these

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Overview

• Choosing a material to use
• Why it is important
• In terms of design, choosing the right material
  enables you to design a product that meets
  customer requirements and expectations with a
  minimum of waste and cost
• In terms of manufacturing, materials selection
  affects processability, inventory costs,
  production process scheduling, optimization of
  production process planning, waste and cost of
  waste
• In terms of the product, materials selection
  affects touch, appearance, user perception,
  performance and longevity, cost of product

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Overview

• Materials SelectionChoosing a material to use
• Why it is important
• Material choice affects everything about a
  product
• How successful it is in the application
• How well it is received by the consumer
• The likelihood of consumer lawsuits
• The cost of production
• The cost of processing
• The cost of and options for end-of-life
  disposition

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Materials Selection Methods

• How do people in industry choose materials?
• They use the same material their company used for
  the product the last time they made it (CYA
  behavior)
• They go to a materials vendor and ask for an
  engineered solution.
• It is rare that a product engineer will go out on
  a limb and recommend a completely new material
• The upshot of that is that the opportunity for
  reengineering products is huge, with potentially
  huge benefits for customers via product
  performance.

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Choosing a Material First Principles

• Understand the application
• What is the product going to be used for?
• Describe the application
• Environment, and characteristics of it
• Mechanical demands
• Expected/Intended uses
• Likely or probable unintended uses
• Likely consequences of misuse or abuse
• Describe the user
• Range of level of training to the product
• Age range

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Understand the application

• What is the product going to be used for?
• Expected vs. Intended uses
• Likely or probable unintended uses
• Case in point using a flathead screwdriver as
  a pry bar
• Likely consequences of misuse or abuse
• Level of risk Safety margins linked to level of
  risk
• For some products, failure may result in a simple
  termination of function of the product (e.g. cell
  phone)
• For some products, failure may result in death or
  risk of death or severe injury (e.g. failure of a
  wing strut on an airplane, or fracture of a tie
  rod on an auto.)

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Describe the application

• Environmental factors
• Physical factors or forces (radiation,
  temperature, electrical or magnetic forces)
• Chemical factors (anything that can change the
  structure or chemistry of a material
  combustion, oxidation, corrosion)
• Mechanical demands
• Mechanical (impact, friction, tension/
  compression/ shear) forces acting on the product
• Design Issues
• Shape alternatives limited by function of part
• Relevance of aesthetics to user acceptance
• Process alternatives limited by shape limitations
  (a common problem for CAD jockeys)

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Describe the User

• Likelihood of misuse or abuse of product
• Range of level of training to the product
• Age range
• Other factors?
• Examples
• Dropping of countertop phones
• Using a screwdriver as a pry-bar, to open paint
  cans, as a chisel
• Others can you think of any?

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Environment

• Physical and Chemical forces acting on the
  product
• Factors that encourage Corrosion
• Dissimilar metals (corrosion potential)
• Use of highly active alloys or materials
• Highly corrosive environments acidic or hard
  water
• Stressed metal parts (areas of stress more
  electrochemically active)

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Environment

• Corrosion prevention or inhibition
• Similar metals in terms of corrosion potential,
  or electrical separation (insulation) of
  dissimilar metals
• Corrosion-resistant alloys or materials
• Plastics, composites, woods
• direct current protection for ships in dry dock
• Anodic protection (zinc, magnesium) for ships in
  open water, tanks, sheet metal surfaces
• Coatings (least effective in long term)

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Environment

• Physical and Chemical forces acting on the
  product
• Weather
• UV Sunlight exposure
• Atmosphere humidity, ozone, solvents, chemicals
• Working Environment
• Ozone (electrical motors)
• Oil or hydrocarbons (automotive)
• Temperature range (thermal exposure, creep,
  thermal expansion and/or contraction).
• Thermal cycling can be a real problem for some
  high tech and aerospace applications.

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Mechanical Stresses

• Mechanical forces acting on the product
• Types and levels
• Tension
• Compression
• Bending/flexure
• Torsion
• Shear
• Modes
• Impact vs. steady state forces
• Cyclic / Vibration

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Process Selection

• Shape alternatives limited by function of part
  what the part has to do
• Process alternatives limited by shape limitations
• Process selection is axiomatic, that is, it is
  based on how much the process planner/designer
  understands about the rules of processing (what
  can and cannot be done).
• The more a designer understands about processing,
  the better his or her choice of processing method
  will be.
• This is why product designers should have
  hands-on experience with material processing,
  learning how to use, and gaining practical
  experience in, milling, turning, casting, etc.
• More experienced designers know more and make
  better choices
• This is where many CAD jockeys get into trouble.
  They want to do product design but may not know
  how materials are shaped into products.

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Cost is ALWAYS an issue

• Earlier changes in product design control costs

Later changes in design increase costs
exponentially
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How to Control Costs

• Factors that influence cost
• Design of product
• Amount of material, strength-to-weight ratio or
  other special properties required, excessive
  precision
• Choice of material
• Raw material cost, additional costs due to low
  availability
• Choice of process
• Expense of basic process
• Waste produced by processing
• Cost of secondary operations
• Changes in design after initial prototyping(see
  last slide)

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Materials for Drafting, Construction, and
Manufacturing

• The End
• (see also Materials Testing for Drafting, )
• This presentation and other materials available
  on the authors website

Thank you for participating! sbates_at_sjsu.edu /
408 924-3227 http//www.engr.sjsu.edu/sbates http
//www.citea.org/resources.htm
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• Image Resources
• Next pages

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Images misc
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Images - mechanical