MEC 1011 - Design Communication I
Mid-term Project 2005
Clarification added 10/6 in this color (below)
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.
sketch (freehand pencil on plain 8 ½ x 11) of modest refinements to the design of a
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_05/Midterm/TXA/Your_Name/ that saves your models next to
or below itself.
Develop a design guide, using Word, 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). Consider table and outline structures for your design guide
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'
at 1:1 and turn your set of A-size drawings (8 ½ x 11) in to an Instructor.
Also, turn in your peer’s set of drawings marked-up by you. Be
sure to share the set with the author before turning it in.
with one of the photocopied example projects for a simple machine,
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
note that each example presents some mechanical motion.
- Completeness: Sketch(es), each working drawing, and
the set of drawings must be complete.
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
of Working Drawings (at least one assembly drawing and part drawings of each
Include formal (consider standard ANSI) title block and border. Confirm stated
Drawing(s): 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.
Drawings: Include all views and dimensions necessary to define the part
geometry. Tolerance all dimensions except stock sizes (including angles). Note
material, units and projection system.
Model and dimension in metric units.
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 model holes.
a hole’s location by referencing a center mark or centerline.
extension lines with visible ‘gaps’.
multiple parts per drawing or multiple drawings per Inventor drawing file
(.idw). Also, avoid multiple parts per Inventor part file (.ipt).
meaningful names to your Inventor files.
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 5/8).
Choose your sizes of stock or standard components by using
the Inventor’s Content
(Inventor menu), a manufacturer’s catalog (list of Component
suppliers on Dept page) or from among the preferred sizes on this list from Columbia University’s Mechanical
Engineering Department. If you choose a component from a
Manufacturer’s catalog, please include the relevant info (Company, part#, etc.)
in your parts list.
dimensioning rules of Figure 12.48 like locating holes in view looking down
dimensions off the views (Figure 12.43).
over dimensioning (saying the same thing twice).
geometric dimensions and tolerances where appropriate to lower manufacturing
consistent with process capabilities as stated in your design guide.
unused Inventor sketches (it’s easiest to kill them immediately).
unused projected geometry in sketches. This is most easily done by confirming
the status of Tools/Application Options/Sketch/Automatically Project Face
work planes and axes exist for a good reason.
are placed on a 'Point, Hole
Center' or solely as a
feature (avoid extruding cut circles or placing hole features on sketched
are tapped by modifying a hole feature (not by adding a thread feature).
part finish (using notes or symbols).
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.
complexity only after you have completeness.
Links to Projects: