MEC 1012 - Design Communication II
Adaptivity, Weldments and Multistage Documentation
This assignment is now
due in combination with Assignment 5 at the end of your TXL meeting in week 12.
Each student must meet the conditions
and objectives of this assignment in order to earn a passing grade in the
Much of a parametric solid modeling system’s power comes from its
ability to ‘adapt’ to changes based on the designer’s expressed
intent. You will demonstrate many of Inventor’s methods of modeling for
adaptivity. Weldments are a special form of assembly that allows the addition
of weld features. Multistage documentation is used to show preliminary stages
of fabrication (such as a part as-cast, but prior to machining).
Your assembly must follow the basic concept shown in the sketch above.
must adhere to the standards of completeness and quality outlined in
Priorities 1 and 2 of the MEC 1011 Final Project
Your tolerances must
be consistent with your design guide’s stated process capabilities and
minimum clearances (i.e. your parts must fit together and be
the minimum clearance between the base’s mount holes and a stated
standard fastener presuming an identical set of holes in the
‘table’. This does not require
geometric tolerances, but consider using them anyway.
Links to Detailed Descriptions (use this as a checklist)
Illustration Highlighting Adaptivity - Make sure
it's clear exactly where you have demonstrated what. Consider using a .idw
sheet with a labeled view of your assembly or provide a labeled sketch (example)
Algebraic Equation - A relationship that uses
variables. Inventor calls its variables 'parameters' and allows you to call on
the current value of a parameter by including the name of the parameter in an
equation (ex. d0=10in, or Wall=2mm, or Length= 2*Width)
Model Parameters - These are created when you
add general dimensions and features to the model (named by default d0, d1
User Parameters - These are predetermined
numbers/algebraic equations independent of features. These are best for values
used repeatedly such as draft, wall thickness and so on.
Linked Parameters -These are laid out on a
spreadsheet (Excel) and then linked to one or more models. A value change in
the spreadsheet is immediately reflected in the model (after update). This is a
permanent relationship so the spreadsheet MUST reside in the workgroup folder.
(Or the path must be designated in the project file.)
How to set up the spreadsheet:
- Use A1 to
label the purpose of the spreadsheet.
- Add column labels in a lower row.
- Use column A to add parameter names.
- Place values and units in the following
When linking or
embedding the spreadsheet you MUST designate the first cell which has the label
for the first row of values. (In the example A5)
Consider setting up a
spreadsheet to drive the casting parameters of your base.
Embedded Parameters - These are initially laid
out on a spreadsheet (Excel) and then pulled into the model. The link is then
severed to the spreadsheet. Subsequent changes to the original spreadsheet will
NOT be reflected in the model. Instead changes must be made to the embedded
Projection - In sketch mode use 'project geometry' to project an existing
edge (or axis or plane from the same or a different part) into the sketch. The
line in the sketch will adapt to changes in the edge that was projected.
Constraint - By leaving some aspect of a part unspecified
(like leaving out a length dimension in a sketch), that part can be made to
adapt to other parts in an assembly based on assembly constraints. For example,
a block (with length unspecified) could be placed inside a box and mated to
opposite inside walls of the box. The dimensions of the box would then drive
the block. You must have the sketch as well as the feature and part designated
This capability is active when
you see the swirling arrow symbol:
Derived Part or Assembly - This allows you to
use an existing part as the base for a new part. It allows you to scale an
existing part and/or create a mirror image of the original. You cannot modify
the derived features, but you can add new features. If you change the parent
model these changes will be reflected in the derived part. Derived parts also
allow you to make working drawings at various stages of manufacturing (for
example, you can show machining features that are added after welding or
casting by deriving the final part from a weldment or part that models the cast
features. You can also use basic sketch geometry for a derived part to drive
Weldment -This is an assembly mode (under the
application menu) that allows you to add welds to your parts. Specialized
Here you add chamfers for
the welding bead
You designate the surfaces
that touch the bead
These are post-welding
processes that finish the welding stage
Cast Base - Your base must be designed for the
casting process. Specifically, the minimum reasonable tolerance is +/- 1.0% but
no tighter than +/- .05 mm. Create and apply User Parameters for cavity draft,
core draft, wall thickness, and rib thickness
2 degrees min.
1 degree min.
Shut-off and Parting Line
5 degrees min.
Max 60% of Wall Thickness,
Min 1 mm
Produce a complete set of working drawings based on your concept using
Autodesk Inventor. Set up and use an Inventor project file in
V:\MEC\1012\Spring_05\Assignment2\TXA\username. Use A-size portrait or B-size
landscape sheets. Include at least one example of multistage documentation (like base
casting and base). If a size of one of your parts is adaptive by assembly
constraint, then it may have an odd size (like 3.478564). On the working
drawing please show the dimension with many decimals to minimize rounding.
Presumably, the size would be ‘cleaned up’ at a later time. See illustration
Produce the models and drawings necessary to
complement the working drawings to show that your design meets requirements.
Include ‘check sections’ showing drafts, wall thicknesses, etc.
Develop a design
guide, using Word, to compile the rules of the design, ranging from aesthetics
to manufacturing process plans and capabilities (capabilities include minimum
reasonable tolerances and what geometric restrictions apply, like
draft for casting). Your guide should also specify minimum clearances
between mating parts. Consider table and outline structures for your design
guide (see example). Save your design guide (.doc or .htm)
in your V: drive folder.
with a peer. After making all necessary changes based on feedback, you must
indicate who checked the drawings using the 'Checked by' iproperty.
Turn in a paper package
(stapled top left) consisting of:
Set of working
drawings (A-size portrait or B-Size landscape printed 1:1 with drawing scale of
your choice. Fold B-size pages accordion style).
Related Links: (use the
Back button to return to this page)
- Apex Fasteners for mechanical
- More fasteners
sites for gears of all types
- Thomas Register-The BIBLE of
builders of things mechanical
example of A to Z in new product development
- More fasteners BUT check out
the engineering knowledge base
Keep it simple. Completeness and quality are
more important than complexity.
Does your set of working drawings fully define an assembly of parts that
are consistent with your complete design guide?
See Example of a Positional
Typical stuff you’ve seen before shown in this color
by Mary Waldo and Paul Johnson February 2005