CRIMPing

After an initial feasibility analysis, the team chose pneumatics to actuate the crimping motion. The setup uses the compressed air source in our sponsor's workspace, which passes through a regulator that outputs 80 psi. This then passes through a 5/2 solenoid valve, which directs the flow via a 12V electrical signal to either extend or retract the crimp tooling. The tooling can reach a compressive force of 385 lb.

Early testing showed the importance of the tooling used to crimp the Molex Microfit pins, leading to the investment in a nice set of Molex tooling with high functionality. This tooling can accommodate 20-24 AWG wire, and mechanically removes the Molex Microfit pin from the reel as it crimps. Due to its functionality, the tooling required a modular mounting assembly that could be adjusted and fine tuned to achieve the highest quality crimps.

With less than a millimeter of allowable error, the machine needed a way to precisely and consistently feed the wire into the crimper. This was accomplished using a Nema 17 stepper motor with two filament sensors either side. The filament sensors(made for 3D printers) use limit switches to determine if a wire is present. The first sensor tells the system that a wire is approaching, and the second sensor tells the motor exactly how far the wire is. Using this information, the wire can be fed the exact length needed consistently and within tolerance.

The crimper has its own microcontroller, an Arduino nano, which operates the relays for the solenoid valve, and the control signals for the motor driver. The Arduino uses inputs from the filament sensors to move the wire through the crimper consistently regardless of the wire length.