# A Decision-Making Tool Based on Exploratory Visualization for the Automotive Industry
## 3 A Real Case Study: Waterjet Cutting
### Cyclone  
The following is the normal process when manufacturing a piece in the waterjet machine (Figure 3): the worker places a part inside the machine and gives the start order, and the cut operation is performed in a continuous way during the cycle. The water pressure generated by the intensifier reaches the level required by the robots in the waterjet for performing the complete cut of the piece. By means of a vacuum system, both the excess water and the cutting leftovers from the work are drained through a vacuum cyclone unit. Cyclone failures are usually related to the vacuum system that the cyclone motor itself runs. This suction is responsible for securing the piece to be cut, in addition to absorbing the remaining water and cuttings leftover from the piece. The generated waste from the waterjet is auctioned towards a garbage chute. The most representative failures in this area are usually related to blockages in the suction circuit and air outlets, and vacuum malfunctioning. The data stored for detecting failures are related to the cyclone engine, and are obtained from the PLC. Additionally, vibration and temperature sensors have been installed in this motor in order to obtain more information about its status. The dataset for this component comprises 623 samples (February 2020) and 24 parameters (features), described in Table 2, gathered for each manufacturing cycle. Figure 3: _Cont._  
_Appl. Sci._**2020**, _10_, 4355 \begin{table}
\begin{tabular}{c c c} \hline \hline
**Feature Name** & **Description** & **Unit** \\ \hline AccPeak\_g\_avg & Engine vibration average & G \\ AccPeak\_g\_max & Engine vibration maximum & G \\ AccPeak\_g\_min & Engine vibration minimum & G \\ AccPeak\_g\_std & Engine vibration standard deviation & G \\ CmdDutyEngineSpeed\_Hz & Fan RPM setpoint & Hz \\ CmdRestEngineSpeed\_percent & \% RPM idle setpoint & \% \\ CmdVacuumPressure\_BBar & Vacuum pressure setpoint & mBar \\ EngineTemp\_oC\_avg & Engine temperature average & \({}^{o}\)C \\ EngineTemp\_oC\_max & Engine temperature maximum & \({}^{o}\)C \\ EngineTemp\_oC\_min & Engine temperature minimum & \({}^{o}\)C \\ EngineTemp\_oC\_std & Engine temperature standard deviation & \({}^{o}\)C \\ FanSpeed\_Hz\_avg & Fan speed average & Hz \\ FanSpeed\_Hz\_max & Fan speed maximum & Hz \\ FanSpeed\_Hz\_min & Fan speed minimum & Hz \\ FanSpeed\_Hz\_std & Fan speed standard deviation & Hz \\ VacuumPressure\_mBar\_avg & Vacuum pressure sensor1 average & mBar \\ VacuumPressure\_1 mBar\_max & Vacuum pressure sensor1 maximum & mBar \\ VacuumPressure\_1 mBar\_min & Vacuum pressure sensor1 minimum & mBar \\ VacuumPressure\_1 mBar\_std & Vacuum pressure sensor1 standard deviation & mBar \\ VacuumPressure\_2\_mBar\_avg & Vacuum pressure sensor2 average & mBar \\ VacuumPressure\_2\_mBar\_max & Vacuum pressure sensor2 maximum & mBar \\ VacuumPressure\_2\_mBar\_min & Vacuum pressure sensor2 minimum & mBar \\ VacuumPressure\_2\_mBar\_std & Vacuum pressure sensor2 standard deviation & mBar \\ Duration & Cycle time for part production & ms \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Cyclone features. Variables gathered per manufacturing cycle. Figure 3: Example of a waterjet machine with the cyclone and sketch of sensors (red and green circles). (**a**) Waterjet machine. (**b**) Sensors placement sketch. Features are obtained from the machine PLC and from the device installed for detecting vibrations in the engine, as well as the temperature sensor. Data are stored in the cloud for each production cycle, the durations of which vary depending on the part that is being produced. The maximum, minimum, average and standard deviation statistics are calculated during the period and stored. There are two main problems or failures that affect the cyclone:  
* The suction circuit is blocked: the waste absorbing system does not work properly. This is a critical failure as it stops production;
* Vacuum malfunctioning: the vacuum does not work properly. It is an infrequent failure that does not stop production, but could lead to defective parts.