Product Development Technologies

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Product Development Technologies

• Henry C. Co
• Technology and Operations Management,
• California Polytechnic and State University

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Product Design Technologies
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CAED

• Computer-aided engineering design (CAED) includes
  those hardware and software tools that can be
  used in product design and manufacturing
  engineering.
• The major building blocks of CAED include
• Computer-aided design (CAD).
• Engineering analysis.
• Group technology.

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Computer-aided Design (CAD)
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• Using interactive-computer graphics (ICG) to
  draw images on a cathode-ray tube (CRT) screen.
  
• A drawing can be zoomed-in for closer scrutiny,
  enlarged or reduced, rotated about any of the
  three axes, or displayed in cross-sections.
• The geometric representation is converted by the
  CAD computer into mathematical models and stored
  in a database.
• Models already stored in the database can be
  retrieved and refined, or merged with another
  model.

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CAD System Architecture
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Hardware and Software

• Hardware.
• Computer,
• Design workstations for design engineers,
• Digitizer (to convert an existing print to X-Y
  coordinate points, which are then stored in the
  CAD database.).
• Automatic drafting machines (to produce high
  quality drawings from data stored in the CAD
  database.).

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Hardware and Software

• Software.
• Graphics packages for drafting, and application
  programs to facilitate the engineering functions
  of the user company.
• Application programs include software used in
  analyzing stress-strain of components, in
  predicting the dynamic response of mechanisms, in
  heat-transfer calculations, and in numerical
  control part programming, etc.

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CAD I/O Peripherals
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Interactive-computer Graphics

• In CAD modeling, design engineers use
  interactive-computer graphics (ICG) to display
  drawings in 2 or 3 dimensions.
• Benefits of ICG
• Improved visualization of the item being created.
• Ability to examine alternative designs in a
  relatively short period of time (compared to the
  drawing board approach).
• Ease in designing the mating parts that are to be
  assembled together in the product.
• Capability to simulate the operation of the item
  being designed.
• Ability to solve computational design problems
  conveniently and in real time.

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Interactive-computer Graphics

• With ICG, drawings can be rotated about any three
  axes, enlarged or reduced, and cross sections can
  be displayed.
• Specific elements of a drawing can be zoomed-in
  for closer scrutiny.
• Drawings already stored in the database can be
  retrieved and added to the drawing.
• Most CAD systems currently available offer
  extensive capabilities for engineering drafting.
• Two ways of representing three dimensional
  models.
• Wireframe.
• Solid modeling (SM).

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Engineering Analysis
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• In nearly any product design, some engineering
  analysis is required.

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• The analysis may involve calculations of volume,
  surface area, weight, strength, stiffness, moment
  of inertia, center of gravity Or it may involve
  finite-element analysis of stress and strain, or
  heat-transfer computations, or solving the
  differential equations describing the dynamic
  behavior of the system being designed.

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• Specific engineering analysis software have been
  developed for commercial distribution, such as
  UNISTRUC for finite-element analysis, IBM's ECAP
  for electric circuit analysis, and programs for
  machine mechanism analysis such as ADAMS
  (automatic dynamic analysis of mechanical
  systems).

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Finite-element Analysis

• The general approach in finite-element analysis
  is to partition a design problem into many
  non-overlapping small (but finite) elements.
• Finite-element modeling has been successfully
  applied to static stress analysis, dynamic stress
  analysis (vibrations), fluid flow problems, and
  the modeling of casting and forming processes.

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Kinematic Analysis

• Kinematic analysis is used to determine whether
  or not a mechanism can perform its assigned task
  or not.
• In kinematic analysis, the motion of selected
  components of the mechanism is specified, and the
  resulting motion of the entire mechanism is
  determined.
• For example, direct kinematic analysis is used in
  robotics to determine the robot arm's position,
  orientation, and rate of change, given the
  angles, displacement, and speed of the axes of
  motion.

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Dynamic Analysis

• In dynamic analysis, the differential equations
  from Newton's laws of motion are solved to
  determine the response of the mechanism to
  external forces.
• The analysis determines how a mechanism will
  perform under realistic loads.

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Animation

• Animation is the process of watching a design in
  action, on a CRT screen.
• Animation is an excellent way of presenting the
  results of dynamic and kinematic analyses.
• It is also the best way to visualize the changes
  to a design if some critical parameter is
  changed.
• Animation is a good way to gain insights into
  changes that can improve the design.

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Computer-aided Testing

• In computer-aided testing, analytical data is
  combined with experimental data to predicting the
  response of the designed product under various
  operating conditions.
• For example, in an automotive application, input
  data may simulate wheel unbalance, braking,
  turning, or tire impact with a curb.
• The computer program responds by predicting the
  response of the total vehicle of these
  conditions.

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Tolerance and Tolerance Analysis

• Tolerances are the allowable variations between
  the nominal design and any real embodiment of
  that design. These variations are caused by
  variations in the manufacturing processes,
  differences in the temperatures during operation,
  changes due to wear and erosion, and unexpected
  applications of the design. Tolerance analysis
  is the study of the impact of these variations on
  the function and performance of the design.

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Group Technology
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• The technique of identifying and bringing
  together related or similar parts in a production
  process in order to utilize the inherent economy
  of flow production methods.
• C. V. B. Solaja of the institute of machine tools
  in Belgrade, Yugoslavia defined group technology.
• Group technology is a manufacturing philosophy in
  which similar parts are identified and grouped
  together to take advantage of their similarities
  in design and manufacturing.

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• Group technology (GT) is a manufacturing
  philosophy where similar objects are identified
  and grouped together to take advantage of their
  similarities in design and manufacturing.
• Parts with similar characteristics are grouped
  into families.
• Families may be based on similarities in design
  attributes such as geometric shape and size, or
  manufacturing attributes such as sequence of
  processing steps required, jigs, fixtures, and
  tooling.

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Two Applications

• GT Layout
• Computer-aided Process Planning