MEC 1011 - Design Communication I Mid-term Project
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This project will emphasize one of the middle phases of a typical design
process. Consider the photocopied example projects for the design of some
simple machines. Many of these designs are just at the end of the conceptual
design phase. Your job is to build a computer model of the machine, refine
the design (considering fit, function, manufacturing, aesthetics etc.) and document
the refined design.
·Produce a concept sketch(freehand pencil on plain 8 ½ x
11) of modest refinements to the design of a simple machine.
·Produce a complete set of working drawings for
the refined design using
Autodesk Inventor. Set up and use an Inventor project file in V:
/MEC/1011/Fall_04/Mid-term/TXA/aaammdd/ that saves your models next to or below itself.
·Develop a design
to compile the rules of the design, ranging from aesthetics (ex. brushed
stainless parts fastened with black socket-head cap screws) to manufacturing
process plans and capabilities (capabilities
include what tolerances are reasonable and what geometric restrictions apply,
like draft for casting).Save your design guide (.doc or .htm) in your Mid-term
project V: drive folder.
·Exchange feedback with a peer through marked-up paper plots. After
making all necessary changes based on feedback, you must indicate who checked
the drawings using the 'Checked by' iproperty.
·Plot at 1:1 and turn your set of A-size drawings
(8 ½ x 11) in to an Instructor.
·Start with one of the photocopied example
projects for a simple machine,
·Develop your own comparably complex design. You may
start with any existing design whose drawings don’t yet exist. As a test
of complexity, consider that a typical design from the examples
has 6 custom parts and some standard fasteners or components.
Also, note that each example presents some mechanical motion.
Completeness: Sketches, each working drawing, and
the set of drawings must be complete.
·Sketches: Draw freehand with pencil on plain 8 ½
x 11 paper. Include title at the top, notes that explain your ideas,
refinements, and how the parts will be made, name of designer (you), your
signature, and the date
·Working Drawings: Include formal (consider
standard ANSI) title block and border. Confirm stated scale.
·Assembly Drawing: Include any combination of
views (ortho, section, iso, exploded or assembled) necessary to clearly show
what parts and how they go together. Also, include balloons, a parts list and
trails for any explosion. The parts list should at least include Item number,
Quantity, and a column to name custom parts and specify standard ones.
·Part Drawings: Include all views and dimensions
necessary to define the part geometry. Tolerance all dimensions. Note material,
units and projection system.
·Drawing Set: Include an assembly drawing and
part drawings of each custom part.
Challenge: Model and dimension in metric units.
·Avoid Contradictions: Never use the
decimal places of the style (appearance) of
a dimension (unfortunately Inventor calls this the
‘precision’ of the number) to round off a quantity. For
example, if the length of a feature is 1.625, you should not allow its
dimension to state 1.6.
·Dimension hole sizes and list characteristics
using hole notes. This requires the also desirable use of hole features to
·Dimension a hole’s location by referencing
a centermark or centerline.
·Place extension lines with visible
·Avoid multiple parts per drawing or multiple
drawings per Inventor drawing file (.idw). Also, avoid multiple parts per
Inventor part file (.ipt).
·Give meaningful names to your Inventor files.
·If you’re stuck designing in English
units, think in simple decimal sizes when you design (like 1.6), and use
fractional sizes for stock and standard components only. When you use
fractional sizes (like 1.625), dimension them with a fractional style (like 1
·Follow dimensioning rules of Figure 12.48 like
locating holes in view looking down hole.
·Place dimensions off the views (Figure 12.43).
·Avoid over dimensioning (saying the same thing
·Apply geometric dimensions and tolerances where
appropriate to lower manufacturing cost.
·Tolerance consistent with process capabilities
as stated in your design guide.
·Delete unused Inventor sketches (it’s
easiest to kill them immediately).
·Avoid unused projected geometry in sketches. This
is most easily done by confirming the status of Tools/Application
Options/Sketch/Automatically Project Face Boundaries.
·All work planes and axes exist for a good
·Holes are placed on a 'Point, HoleCenter'
(avoid extruding cut circles or placing hole features on sketched circles).
·Holes are tapped by modifying a hole feature
(not by adding a thread feature).
·Specify part finish (using notes or symbols).
·Where a part is symmetrical, indicate symmetry
with a centerline and tolerance the symmetry with a note.
Complexity. Notice this is the LAST PRIORITY. Look
up at Completeness. Before you make your design more complex, consider
having a friend with a sharp eye look over your drawings. Your most
insidious foe is the missing dimension.