MEC 1012 - Design Communication II
Design and Data for Prototypes
This assignment is
due at the end of your TXL meeting in week 15.
Many prototyping technologies use geometric computer models as a basis for
fabrication. If you design using computer models then you’re most of the
way there already, but some format translation will likely be necessary.
We’ll focus on Vermont Tech’s CNC machining and Fused Deposition
Modeling (FDM, “rapid prototyper” http://www.efunda.com/processes/rapid_prototyping/fdm.cfm
We’ll review sheet metal modeling and then use the flat pattern
geometry to feed the CNC programming process. At production volumes, sheet
metal parts are often punched and formed with costly custom dies. While CNC is
also used for production it can be very cost effective for the low volumes
(numbers of manufactured parts) associated with prototyping. We’re
programming CNC with a 2D system called SpectraCAM, so we’ll make a 2D
dxf file with a carefully located origin.
FDM is most effective for small, intricate plastic parts that might
otherwise need costly molds. The rapid prototyper takes an stl file format
based on the layering scheme of FDM.
Model an object for FDM (or use an existing
model) with a volume no greater than one cubic inch. Try to minimize the need
for support material (i.e a box with an open top needs little, but a closed top
needs a lot. Hopefully, each student will have an opportunity to build their
part. If you’re not using all of you allotted volume, you may
‘donate’ it to another student.
Model a sheet metal part for which Inventor can
successfully generate a flat pattern. Consider looking over the sheet metal
parts in the samples project (C:\Program Files\Autodesk\Inventor
Produce an ipt and the associated stl file. If
your part exceeds a cubic inch, indicate who ‘donated’ the extra
Produce a sheet metal ipt and the associated dxf
file with origin located in a noted location.
Keep it simple. Completeness and quality are
more important than complexity.
Typical stuff you’ve seen before shown in this color
by Mary Waldo and Paul Johnson April 2005