Top down assembly

Presented by-

Dilip kumar garg

Jayant sarode1

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.

2

3

Assembly Modeling Approaches

• Bottom Up Assembly

• Top Down Assembly

• Combination

4

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

5

6

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.

7

Top Down Assembly

• Assembly file is created first with an assemblylayout sketch.

• The parts are made in the assembly file itself andthen assembled using assembled using assemblyconstraints.

• The new parts are created relative to othercomponents.

• We create a skeleton first at the top of thehierarchy and move down the hierarchy, creatingsubassemblies and components.

8

9

Skeletons

What is it

• Zero-mass geometry

• Exact location detail

• Minimized geometric detail

10

Definitely Not this

11

Example to Design an Alternator

12

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

Assembly of by top Down Approach

13

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

14

Applications of top down Assembly

15