For our midterm project, we made a mechanical model that “launches” a rocket. We wanted the rocket to move up and down linearly, so we decided to use a rack and pinion mechanism, with the rack attached to the rocket and the pinion fixed in place to operate the rack. We started by sketching out the design on paper to get a general idea of how we wanted it to look and work.
Once we had an idea of how we wanted it to look, we decided to design the mechanism in CAD. We mostly did this to see how the rack and pinion interact, and to plan where to put the pinion relative to the rest of the model.
From this CAD, we wanted to make a cardboard prototype to prove its viability. We used the laser cutter to cut the cardboard out and assemble it.
Although the pieces didn’t fit perfectly, they did prove that the design could work. We did a redesign of the system so that the pieces fit better together, and then we were ready to laser-cut the parts out of wood.
From that, we began the assembly process. We first assembled the base, using wood glue to attach the back plate to the base plate. We also used laser-cut brackets (both a square and triangle bracket) to make sure it was at 90 degrees. We let this dry overnight, and then assembled the rest of the model. The launch tower was attached at the base plate and the back plate for extra support and the rack was fastened to the back of the rocket using 2 1/4-28 x 3/4″ bolts. These two bolts ensured a tight connection. Finally, the pinion was glued onto its shaft and spaced out using popsicle sticks. Also, a guiding shaft was used on the other side of the rocket to make sure the rocket rack didn’t disengage from the pinion.
Once everything was assembled, the last step was to post-process with Danish oil! We let it dry, and then it was complete.
Video of machine working: IMG_8998
Power Point: https://docs.google.com/presentation/d/1eVtT3HEEZOg-ArZx0YNI4PLxTovW2KioKqy-9I7V7zw/edit?usp=sharing
Cost analysis:
Wood (1 sheet of 30×20 wood): $10
Steel: $10
Time (15 hours @ $20/hr): $300
Total: $320
