Phase 2 Design Project

DESIGN PROBLEM
for the
1998 ASME Student Design Contest

"Widget Inspection"

A manufacturer wishes to perform automated inspection at the end of its assembly line to result in better quality control of its product. The widget produced by the line has a rectangular shape with an off-center hole (see figure below). Due to flaws in the manufacturing process, sometimes the hole is not present. The manufacturer wants a system that can separate "good" (with hole) and "bad" (without hole) widgets automatically, quickly and reliably. In order to generate feasible concepts they are offering ASME Student Members the opportunity to design and build a prototype system to meet the following specific requirements:

1. Design and build a system to quickly and reliably separate "good" widgets from "bad."

2. The system can be actuated only by unmodified Radio Shack DC motors (part no. 273-223 only). Each motor can be powered only by a single Radio Shack Alkaline Enercell 1.5V AA battery (part no. 23-557, 23-552, or 23-652). No additional energy sources are allowed. Also, any energy storage devices other than the batteries (e.g., springs, capacitors, falling masses) must each end the run with the same or more energy than at the start. All net energy used in the separation process must come from the battery.

Before assembly or placement, the complete system must fit within a 16x16x32 cm box (inside dimensions). The system must be assembled from the box, if assembly is required, within five minutes. Everything except the tools used for assembly, the receiving boxes mentioned in item 4, and the widgets are considered to be part of the system.

3. Ten widgets, five "good" and five "bad," will be released into your system all at once by a judge from 2 to 5 cm above a team-specified location. First, the widgets will be placed in a 2 1/4 quart pitcher (Rubbermaid product number 3062), the cover will be placed on the pitcher, and the widgets will be thoroughly shaken. The cover will then be removed and a smooth flat surface (e.g., a sheet of Plexiglas) will be placed over the mouth of the pitcher. The pitcher will then be inverted and positioned over the designated release location. The pitcher will be vertical and the flat surface will be horizontal at this time. On the release signal the judge will slide the surface away from the pitcher quickly releasing all ten widgets into the system.Your system should deposit the "good" widgets into a box marked "good" and deposit the "bad" widgets into a box marked "bad." The receiving boxes are 22.9x15.2x5.1 cm (9x6x2 in) drawer organizers made by Rubbermaid (product number 2916). They are attached on their long sides and are placed open side up on a flat, level surface. Both the pitcher and the drawer organizers are readily available at most department stores (e.g., Wal-Mart or K-Mart).

4. After the system is in place and while operating there must be a clear view into both boxes so that the judges can determine when the last widget has been processed.

5. When ready the team must give the judge a signal to release the widgets. The system can be switched on, if necessary, when the release signal is given. The time starts on the release signal and ends when all ten widgets come to rest in the boxes. The maximum amount of time allowed for the separation is two minutes. If less than ten widgets come to rest in the boxes a separation time of two minutes will be used in the scoring.

6. No external communication, interaction, or influence of any kind is allowed - the system must be completely autonomous.

7. The best design will be the one with the highest score computed as follows:

1. SCORE = 1000 + 50*N - T

2. where

3.
N = number of widgets separated correctly

4. = number of "good" widgets in the "good" box

5. + number of "bad" widgets in the "bad" box.

T = time (in sec to the nearest tenth) to process all ten widgets.

6.

7. If multiple trials are allowed or required, the average score of the trials will be used to select a winner. If necessary to determine a winner, the judges may require a run-off with an increased number of widgets.

8.