The assembly video for the quadcopter is shown below.
Early in the design, we decided to connect the frame parts with tight fit joints instead of using screws. One of the reasons was because the metal screws would increase the overall copter weight. The other reason was because small screws can be difficult to disassemble and reassemble. Using a tight fit, the arms are joined together with the base plate in a secure manner, and the resulting frame can easily be taken apart for maintenance or to replace parts. However after dropping the quadcopter several times, this type of fitting becomes loose as the material becomes fatigued. To resolve this issue from happening again, a screw was eventually used to ensure security of the part.
The batteries that were used to power the motors run at a high current of over 3.5 amps which is enough to cause regular circuit boards to over heat. Terminal ports were used instead to connect the motors to the battery. The leads of the terminal ports were shorted by soldering a piece of thick wire and the ports were then glued onto the base plate. The motor wires that use the terminal ports are secured using a screw which makes it very easy to add extra wires to power additional devices (e.g. micro-controller or sonar sensor). The back side of the base plate is where the wires are connected together to the battery. This is also where the flip switch is installed to turn the entire unit on or off.
The battery is secured with the use of two plastic clips that were printed using the 3D printer. The clips are secured using two screws that allows the clips to pivot. When a battery is low on power it can easily be replaced by detaching it from the power terminals and slipping it out of the clips. The space allocated allows it to fit a max battery size of 35 mm by 110 mm by 27 mm.
The ESCs were not easy to fit into the quadcopter frame design because the wires were a bit too long and the device could not fit into the spacing between the arms (at first). The initial method of securing the the ESCs was by using zap straps to tie them to the base plate and in front of the terminal ports. This design proved to be too inconvenient when trying to access the terminal ports for power and taking apart the arms for maintenance required us to redo the zap straps all over again. The design was improved when the alignment of the motor were turned around allowing the ESC to fit comfortably in between the arms as originally intended.