The 2.810 group project this term will consist of the fabrication of "N" radio controlled cars for each group of N students. You will start with the following list of materials per car.
* four foam rubber tires (choice of 3 sizes)
* front steering assembly components
* rear wheel assembly components
* electric motor + 2 sets of batteries per group
* one radio controller per group
( including steering servo and speed control)
and one battery charger
The group project will consist of the fabrication of the body shell, chassis and wheel hubs and the final assembly of the car. The aluminum chassis can be made by either sheet metal forming or sand casting. Fabrication by sand casting requires the design and machining of a casting pattern. The pattern will be taken to a local vendor, who will perform the casting. Fabrication by forming can be done in Building 35. The shell and wheel hubs will be thermoformed and injection molded respectively, using tooling provided by Gerry Wentworth. The performance of the cars will be evaluated in a contest on the final day of class. The contest includes the driving of each car (all group members participate in driving) around a designated loop on flat, carpeted floor (see figure 1) and the disassembly and assembly of the radio controlled unit into each subsequent car. There are Nmax laps and Nmax pit stops). Cars are limited in size to 12"X18"X12".
Figure 1. Race track layout. Track is bounded by 2-x-4's.
Each group must design their
cars for assembly and disassembly of the radio control unit during the
race. No modification of the radio control is allowed. All assembly must
be made by mechanical fastening only. Glue, adhesives, tape, Velcro or
similar products are generally not allowed. All requests for clarification
of the rules, and decisions will be made by email so that all results are
made public instantly.
The fabrication of the radio controlled car chassis by sand casting requires the design and fabrication of a casting pattern. This will be done using MasterCAM (ver 7.0) software. A special lecture will be given by Gerry Wentworth on the use of this software, including the drawing of the chassis, the generation of tool paths and the down loading to the Cincinatti-Millicron 3-axis Milling Machine. Additional learning of the software and demonstrations on the milling machine, thermoforming machine and injection molding machine* will take place after class hours. There are eight MasterCAM stations in room 35-135 and an additional station in Building E40. The building 35 facility is shared with the 2.008 class, but is open to you (with the appropriate password) 24 hours a day, seven days a week. It will be required that all members of 2.810 submit a MasterCAM drawing for the chassis, however, only one drawing per group will be machined and used in the sand casting process. For those groups that decide to form their chassis the MasterCAM homework is still required.
Sheet forming of the chassis
will require using SolidWorks or some other CAD software. SolidWorks (
a tutorial is provided for you) will convert your design to a flat drawing.
The flat drawing will be loaded into the waterjet (as a dxf file) and cut.
Bending and additional operations will be performed on the presses and
other equipment in building 35.
3. Group Organization
An important aspect of this
project is that you organize yourselves in groups and carry out the projects
in a cooperative and productive manner. In fact, your first assignment
will be to form into groups ( which this year will range from seven to
eight) to carry out this project. Your responsibilities in the group are
to develop your car design, competitive strategy, and manufacturing tasks
as a group. Your first assignment is to find a mutually agreeable one hour
time period per week to work on this project. We are interested in knowing,
how well your group functions, how the work load is distributed, and how
you dealt with problems and conflicts. This information will be reported
in your final report and group progress reports. (Past experience has shown
a very strong correlation between well functioning groups and a successful
physical product.) The group should designate a "secretary" to record important
decisions and problems and to prepare the group progress reports. You will
need to record your organizational structure, the evolution of your design
(using drawings and design ideas), the division of tasks etc. for your
4. Physical Product
The most important aspect
of this project is that your group successfully complete the assembled
cars using the various manufacturing processes. You will be required
to build N cars for a group of N people. After the contest one car will
be left with the instructors for grading. The car will be returned in about
one week. The car should demonstrate good design and manufacturing technique,
with the aim of demonstrating a satisfactory performance in the final race
and assembly contest. Each group will receive a letter designation i.e.
"A", "B" etc. which, along with the car number, must be prominently displayed
on all cars during the race (i.e A1, A2...) By the way, the winners of
this contest will win the coveted 2.810 CAD-CAM-"CAH" award ( as in "pahk
yah cah in havahd yahd").
A short report is
required to accompany your car on the day of the contest. The report should
1. A photo of your car
2. A list of group members and photo
3. Design drawings (engineering quality) for chassis and assembly
4. Tasks performed by each group member and a rough estimate of the total group man/hours devoted to this project.
5. Time estimate in seconds for the disassembly/assembly as will be performed for each pit stop during the race.
6. Group strategy and comment on the functioning of the group.
7. Very brief discussion
of the key design and manufacturing issues which your group had to deal
with, and what lessons were learned.
Please try to acknowledge
the sources of ideas your group used and give proper references ( as you
would see in a technical paper ). The text of this report should be written
in the spirit of an executive summary. Please use 12 point Font, adequate
margins (at least 1") and 1 1/2 spaces. Do not exceed 6 pages of text (not
counting photos, drawings, & tables). No appendices are allowed.
Each of the group projects
will be graded as a group, that is, one grade will be assigned to the entire
group. Therefore, it is the group's responsibility that each member contributes
equally. The grade will depend primarily upon the physical cars and the
effort demonstrated in producing it. Quality of manufactured parts, fit
and finish and performance of the assembly and disassembly scheme as judged
by the instructors will all be considered in the grading. In addition,
performance in the contest on the final day of class will also be considered.
The final report describing the cars and the group effort will contribute
about 10% of the project grade. Overall the project will count for
40% of your grade and the two quizzes will count 30% each. Significant
extra credit will be given for class participation (up to 5%). All quizzes
are open book, open notes.
7. Project Schedule
Key dates for the 2.810 project for the Fall 1999 are:
Sept. 13 or 15 - MasterCAM Lecture
Sept 29 - Pattern Design Discussion
October 25 - CAD chassis Drawings
October 25 - Pattern Machined for Foundry (this week)
October 25 - One paragraph written report on the group
November 1 - Schedule Casting for this week or before
November 10 - Oral Progress Reports
December 6 - Contest Preparation
December 8 - Contest