Assembly Modeling In an assembly model, components are brought together to define a larger, more complex product representation.

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Assembly ModelingIn an
assembly model, components are brought together
to define a larger, more complex product
representation.
Assembly modeling is a tool that allows and
facilitates the collaboration among designers,
analysis people, manufacturing people, and
others, to insure their assembly works together.
This enables individuals in different disciplines
to work concurrently, resulting in faster and
less costly delivery of products to market.
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Assembly Modeling

• Constructing an assembly begins with bringing in
  a base component, selected because of its central
  role.

• Each component brought in needs to be oriented
  and located relative to other components in the
  assembly.

• Geometric relations (constraints) are used
  between elements of components.

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Assembly Modeling

• Bottom-Up Design (Modeling) this is a logical,
  traditional, and most common approach. The
  individual parts a created independently,
  inserted into the assembly, and located and
  oriented (using the mating conditions) as
  required by the design.

The bottom-up-approach is the preferred technique
if the parts have already been created (off the
shelf). It allows the designer to focus on the
individual parts. It also makes it easier to
maintain the relationships and regeneration
behavior of parts than in the top-down approach.
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Bottom-Up Design (Modeling)
The components (parts) are created first and then
added to the assembly file. This technique is
particularly useful when parts already exist from
previous designs and are being re-used.
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Assembly Modeling

• Top-Down Design (Modeling) In this approach,
  the assembly file is created first with an
  assembly layout sketch. The parts are made in the
  assembly file or the concept drawing of the parts
  are inserted and finalized in the assembly file.
  In other words, the final geometry of the parts
  have not been defined before bringing them into
  the assembly file. The approach is ideal for
  large assemblies.

• Combination basic geometry for a part is
  established first, then it is brought into an
  assembly for further refinements.

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Locating Orienting Parts in the Assembly Mating
Conditions
Most common mating conditions are Coincident,
Concentric, Tangent, Coplanar, Parallel and
Perpendicular faces, and Offset faces.
Coincident
The coincident mating condition is applied
between to planar faces
Each face is specified by its unit normal vector,
n, and a point on the surface, P. The coincident
condition is satisfied by forcing n1 and n2 to be
opposite of each other, and the two faces touch
each other such that P1 and P2 are coincident
An offset option is provided for this command
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Mating Conditions - Concentric
Concentric
The concentric mating condition is applied
between to cylindrical faces
The concentric mating condition is achieved by
forcing the axes to become collinear. Each axis
is defined by two points.
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Mating Conditions Coplanar (Aligned)
Coplanar
The coplanar mating condition is applied between
to planar faces, and forces them to lie in the
same plane.
Each face is specified by its unit normal vector,
n, and a point on the surface, P. The coplanar
condition is satisfied by forcing n1 and n2 to be
in the same direction, and the two points, P1 and
P2, are chosen to lie on the two edge to mate
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Mating Conditions Tangent
Tangent
The tangent mating condition is applicable
between a planar and cylindrical surfaces or two
cylindrical surfaces.
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Other Mating Conditions

• Parallel
• Perpendicular
• Surface intersecting an edge
• Edge intersecting a point
• Angles of surfaces/planes to each other
• Relationship of a geometry to a coordinate system

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Degrees of Freedom

• There are six degrees of freedom. 
• Translation movement along X, Y, and Z axes
  (three degrees of freedom).
• Rotation rotate around X, Y, and Z axes (three
  degrees of freedom).

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Degrees of Freedom
Coincident
Two selected surfaces become co-planar and face
in opposite directions. This constrains 3 degrees
of freedom (two rotations and one translation)
Parallel
Two planar surfaces are made parallel, not
necessarily co-planar, and face the same
direction (similar to Align Offset except without
the specified distance).
Constrains two degrees of freedom (two rotations)
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Creating an Assembly
Part
Part
Assembly
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Creating an Assembly Example
The example assembly requires three mates to
fully define it.
First constrain Mate between the hollow faces as
shown.
Hollow faces
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Example
Second Constrain Align the right faces of both
components.
Right side faces
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Example Switch Plate
Switch plate consists of two components, plate
and fasteners.
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Example Switch Plate
First Constrain Insert select the cylindrical
face of the fastener and the cylindrical face of
the switch plate.
Two degrees of freedom remains, the fastener can
still move in and out and rotate inside the hole.
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Example Switch Plate
Second Constrain mate the flat circular back
face of the fastener and the flat front face of
the switch plate.
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Example Switch Plate
Align Orient could be used to line up the slot on
the screw head with the flat top face of the
switch plate.
The assembly is fully defined
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Example
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Assembly in SolidWorks
Open an Assembly file
File ? New ? Assembly
Insert a component model
Insert ? Component ? Existing Part
You can also drag and drop components into the
assembly file
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Assembly in SolidWorks
Mate command
Advance Mates
Select entities
Type of Mates
Specifies distance and angle for Mates
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Assembly in SolidWorks
Right click on the part to be modified
You can use the SmartMates to save time.
To create SmartMates while dragging a component

• Hold down Alt and drag a component over potential
  mate partners.
• The component becomes transparent and the pointer
  changes when it is over a valid mate partner.
• Drop the component to apply the mate.

Move the part
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Assembly in UG
Application Assembly
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Assembly in UG

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Assembly in UG
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Assembly in UG
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Pro/E Mate Commands
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Summary

• An assembly contains two or more parts, parts are
  referred to as components. 
• Mating conditions are relationships that align
  and fit components together in an assembly. 
• Components and their assembly are directly
  related through file linking.
• Changes in the components affect the assembly.
• Changes in the assembly affect the components.

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Analysis of the Design

• Design analysis is the evaluation of a proposed
  design
• based on the criteria established in the ideation
  phase.
• Typical analysis
• Property Analysis
• Evaluates a design based on its physical
  properties
• strength, deflection, size, volume, center of
  gravity and rotation, thermal and fluid
  properties, ..
• Finite Element Analysis, Finite Element
  Modeling

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Design and Analysis
Mechanism Analysis Evaluates the motion and loads
associated with mechanical systems made of rigid
bodies connected by joints
Kinematics Determines the motion of assembly
without regard to loads
Dynamic Determines the loads that drive or create
the motion of a mechanism
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Design and Analysis

• Functional Analysis
• Determines if the design meets the
  requirements specified in the ideation phase.
• Engineering goals (targets)

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Design and Analysis

• Human Factors Analysis
• Evaluates the design to determine if the
  product serves the physical, emotional, mental
  and safety needs of the consumer.
• How a design interacts with the dimensions,
  range of motion, senses and mental capabilities
  of the people using the product.
• Reference The Measure of Man, by Henry Dreyfuss.

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Design and Analysis

• Aesthetic Analysis
• Evaluates a design based on the look and feel
  of the product.
• The product is analyzed by industrial
  designers, marketing people and environmental
  and human factors engineers. Difficult to
  measure and quantify.