MEC 1012 - Design Communication II,
Adaptivity, Weldments, Redesign for Casting,
and Multistage Documentation
must earn a passing grade on all challenges to earn a passing grade in the
Start by making a folder: V:\MEC\1012\Spring_05\X\Challenge2\TXA\username.
Copy the Inventor and .htm contents of V:\MEC\1012\Spring_05\X\Challenge2\ (2
parts, an assembly, three drawings and a design guide) to your folder. Start
Inventor and browse to the project file in your folder.
This Challenge is an abbreviated version of Assignment 2 and Assignment 3.
You must modify the design of a table. Your goal
is to redesign the base to be cast, increase the clearance for the fasteners
and weld on a name plate.
You are given a concept sketch for needed
Your models must demonstrate the appropriate
modification and use of various 3D features as called for. Expect to modify
Extrude features to apply a taper by User Parameter, Shell with a
wall thickness by User parameter, create a Rib and apply Face Draft
(also by User Parameter), and Mirror the Rib.
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
‘manufacturable’). This does not
require geometric tolerances, but consider using them anyway.
Redesign the Base to be cast.
Include draft as appropriate with a parting line
at the bottom outside edge. Add ribs as indicated in the concept sketch.
Further, remove the holes from the base casting and model them in a later stage
(using Derived Component).
Presume that the casting process is capable of
at minimum +/- 1.0% but no tighter than +/- .05 mm.
Create and apply User Parameters for
Cavity_Draft, Core_Draft, Wall_Thickness, and Rib_Thickness based on the
following geometric restrictions:
2 degrees min.
1 degree min.
Max 60% of Wall
Thickness, Min 1 mm
Confirm that inside corners have radii at least
equal to the neighboring thickness.
Produce an informal drawing necessary to complement
the working drawings to show that your design meets requirements. Include
‘check sections’ showing drafts, wall thicknesses, etc. For
example, Do your ribs intersect the standard wall at less than or equal to 1.8
mm (60% of 3mm)?
Increase the minimum clearance between the Plate
and the Screws from .15 mm to .2 mm.
Add a Name Plate (keep it simple –
rectangle with engraved letters) to your Assembly and weld it to the center of
Develop a design
guide, using Word, to compile rules of the design. Include 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). You may choose to
simply modify the given Design Guide. Save
your design guide (.doc or .htm) in your V: drive folder.
Produce a complete
set of working drawings using Autodesk Inventor. Set up and use an Inventor
project file in V:\MEC\1012\Spring_05\Challenge2\TXA\username. Use A-size
portrait or B-size landscape sheets. Include
multistage documentation with a drawing of the base as cast and a separate
drawing for hole drilling. Feel free to model your main assembly as a weldment
to avoid the need for a separate weldment drawing.
Turn in a paper
package (stapled top left) consisting of:
Given sketch with tolerance calculation for
minimum clearance between Plate and Screws (see below).
Set of working
drawings (printed 1:1 with drawing scale of your choice. Fold B-size pages
Use section views for clarity where appropriate.
To control the minimum clearance between the
screw fasteners and the clearance holes on the base choose:
Positional Tolerancing where: T is the diameter of the tolerance zone,
H is the MMC hole and F is the MMC fastener with min clearance added to both
sides. For a Floating Fastener case T = H – F and for a Fixed Fastener T
= (H – F)/2. In the Given design we have a Fixed Fastener with H = 9 - .1
= 8.9, and F = 8 + 2(.15) = 8.3 so T = (8.9 – 8.3)/2 = .3 mm.
Rectangular Tolerancing where the hypotenuse of
a square zone can be presumed to be 40% greater than the side.
If the top surface on the Base is cast (far from
flat) the Plate may wobble or tilt. How could we modify the Base to insure a
stable and level Plate?
You shouldn’t need it but, http://www.metrication.com/
is good for metric drill sizes.