Top down assembly modeling involves first creating an assembly file with a skeleton layout sketch. Parts are then created within the assembly file and assembled using constraints. This approach allows designing from the overall assembly down to individual components. Benefits include having all design information centralized, reducing errors, and better managing large assemblies with thousands of parts. However, more upfront analysis is required compared to the bottom up approach of first creating individual parts separately before assembling them.

1. Top down assembly
Presented by-
Dilip kumar garg
Jayant sarode
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2. Assembly
• Assembly modeling is the process of creating designs
that consist of two or more components assembled
together at their respective work positions.
• The components are brought together and assembled
by applying suitable parametric assembly constraints
to them.
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4. Assembly Modeling Approaches
• Bottom Up Assembly
• Top Down Assembly
• Combination
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5. Bottom Up Assembly
• Traditional approach
• Parts are created individually in the part mode
• Inserted into the assembly, located and oriented
(using the constraints) as per requirement
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7. Pros and Cons
• Allows the designer to use part drawings that already exist (off the
shelf).
• Provides the designer with more control over individual parts.
• Any changes in the original part is reflected on all the instances in the
assembly
• Assembly files created in this method occupy less disc space as they
contain only the information related to the assembling of the parts.
• Errors are manually identified and modifications to each component are
made to make the adjustment.
• If any of the assembly components is moved from its original location,
then the assembly will not open.
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8. Top Down Assembly
• Assembly file is created first with an assembly
layout sketch.
• The parts are made in the assembly file itself and
then assembled using assembled using assembly
constraints.
• The new parts are created relative to other
components.
• We create a skeleton first at the top of the
hierarchy and move down the hierarchy, creating
subassemblies and components.
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10. Skeletons
What is it
• Zero-mass geometry
• Exact location detail
• Minimized geometric detail
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11. Definitely Not this
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12. Example to Design an Alternator
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All Skeleton Models
in Top-Level
Assembly
70 MB
Subassembly,
with Skeleton Model containing
all required information ~ 20 MB
Complete Top-Level
Assembly
540 MB
Neighboring
Subassemblies
320MB

13. Assembly of by top Down Approach
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14. Pros and Cons
• The overall design information is in one centralized
location
• Reduce errors within complicated assemblies
• Increased quality
• Better project management visibility
• Concurrent engineering
• Top-level change control
• The approach is ideal for large assemblies consisting of
thousands of parts.
• Creating the top down assembly require more analysis
and work before start
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15. Applications of top down Assembly
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