Banknote transport improvement

This thesis project is developed at Arca technologies s.r.l., a leading global company in building machines able to manage cash, called cash recycler. This machine is a complex one in which banknotes are placed into an input bin and passed through a bill identifier to determine their denomination and validity. The cash is then stored in separate modules, called drawers, for dispensing it in future transactions. The goal of the thesis was improving banknotes transport and consumes of the machine. The first activity consists in improving the cash transport on the machine. Critical points causing issues were individuated in the drawer module. The issue encountered in such module was during a dispense operation. There was encountered difficulties in leafing banknotes in correct way putting frequently the machine in out of service state. The unit aimed to leaf the cash, called skimmer, and the unit where banknotes were deposited, called drum, did not cooperate correctly in all the situations. Key parameters influencing the issue were individuated and, after a parametric analysis, a new kinematics between these units was studied through SolidEdge to guarantee correct working at all situations. A test bench was built to reproduce the issue, perform the parametric analysis, try the modifications and validate them. During the tests, the following instruments were useful: an oscilloscope to acquire and processing signals, a stepper motor driver to put in motion the drawers and a high velocity camera to individuate at details the issue encountered. The second activity regards load and power demand by the machine. The goal was to reduce both to mount smaller motors and smaller power supply to reduce costs. Using torquemeter and oscilloscope the load of the machine and of its modules was analysed in order to individuate the main contributor to overall load. Friction analysis was performed focusing on these ones and modifications were proposed and implemented. The load of the final configuration of the machine was measured as before and compared to the smaller motor torque measured at test bench in order to calculate the safety margin (ratio between these ones). At last a thermal stress test is build up and using a thermocouple the temperature asymptotic value was measured in order to see if there was any overtemperature risk for the motor. For the power reduction activity, the power request signal was acquired during a maximum consumption operation. A current probe was used to acquire the current request and an oscilloscope was used to visualize the signal, which was processed via MATLAB in order to obtain the maximum power consumption. The analysis showed that the modification implemented during the load reduction activities and results obtained was useful also for the machine power consumption reduction mainly due to the machine load reduction and the mayor efficiency of the smaller motor compared to the bigger ones. These allows to achieve the desired goal