Final Team Documentation

Our final machine is in many ways a representation of the original team strategy ("hold the flipper and score balls in the slot while pushing balls from the top of the arena" and concept ("car that drives a wedge into the flipper and using a rotating arm to then score balls") that we came up with for our first team MS at the beginning of the semester.  The machine is composed of three modules, the most critical of which is a rotating arm powered by two six speed gearboxes with motors  and a planetary gearbox with a motor which pushes balls in the slot towards the flipper.  The second module is a pair of a wheels at the front of the car driven by a double gearbox and motor which drives the machine several inches forward from it's starting spot into the slot.  The third and final module is a front arm which falls down several inches from it's starting spot once the wheels drive the machine, which results in the arm falling into the flipper and pushing it towards the opponent's side of the arena.

(The image on the left is our initial solidworks assembly, whereas the image on the right is our final solidworks assembly - note that the empty spaces on the final solidworks assembly are spaces left for the motors)

On an individual level each of the three modules from our machine is able to function the
way that we intended.  The rotating arm is able to move up and down by the mechanical advantage of a rack and pinion, and it is also able to rotate almost the entire width of one side of the slot with enough force to push balls far enough that they score.  The wheels at the front of the car are able to drive the car forward and backwards over the slot with ease, and the front arm falls down at an angle and to a depth that pushes the flipper towards the opponent's side.

The problem with our machine is that the modules do not function in tandem the way that they need to.  Specifically, the front arm does not fall at the right angle or to the right depth when it is forced to do so by the force generated by our machine "falling" into the slot (a desired occurrence created by the driving of the machine's wheels) or by pushing at it's back end by the rotating arm.  Without the front arm pushing the flipper towards the opponent's side of the arena, our machine is unable to score balls even when the wheels drive it to the correct spot and the rotating arm is able to function as desired.

The main reason behind the front arm dropping to the wrong spots and the wrong times would seem to be the machine's angled guide (pictured above).  The angled guide is an aluminum mount which stands in front the front arm to ensure that the front arm is at the correct angle.  After machining our first angled guide it was obvious that the guide could not be too snug on the front arm, or else the front arm would not drop.  Subsequent machining of angled guides revolved around deciding how snug (or loose) to make the angled guide.

Over the course of the semester, our entire team learned a great deal about design and manufacturing.  The machine that we produced is simple but robust, and for the most part we are more than satisfied with how it turned out.  If anything, our experience in mechanical engineering 250 this semester showed us that you are only as strong as your weakest link (ANGLED GUIDE!).  We all look forward to future work in design and manufacturing, and we wish the best of luck to all future slotbot participant and mechanical engineering 250 students, staff, and faculty.

Best regards,

Kazem Alidoost
Christian Groesbeck
Scott Kleiman
Geunbae Lee

~Prestige... Worldwide!