# Stochastic Evaluation of Cutting Tool Load and Surface Quality during Milling of HPL
## 2 Materials and Methods
### Measuring Apparatus for Force and Torque Loading of the Tool during Milling  
The main methods applied in this article are based on measurements and their evaluation. During milling, chips are separated from the base material under the action of the cutting force \(\mathrm{F/N/}\), which acts in the cutting zone and takes on a dynamic phenomenon, constantly changing in the time sequence, i.e., it has a stochastic (probabilistic, random) character. The technical term'stochastic' in this case means the combination of statistics and probability theory in the dynamic and time-dependent problem of surface machining mechanics [23; 24]. At the beginning of the cutting process, the force grows to a certain maximum at which a chip is formed. The shear force in the region of lower cutting speeds rises with increasing speed due to hardening of the deformation. Once the chip is separated from the base material, the cutting force decreases and the same process is followed to separate the next chip. In milling operations, the cross section of the chip changes during chip removal, which leads to a change in the components of the cutting forces. The magnitude \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Cutter**} & **Description and** & \multirow{2}{*}{**Shank Cuter Material**} & \multicolumn{4}{c}{**Material Properties of the Cuter**} \\ \cline{3-6}  & **Dimensions of** & & **Young’s** & **Poisson’s Ratio/1** & **Yield** & **Ultimate** \\  & **the Cutter** & & **Modulus/GP/** & & **Strength/MPa/** & **Strength/GPa/** \\ \hline DPØ10 \(\times\) 12/60, & Shank cuter with two soldered cutting edges & Tool (510) & 210 & 0.3 & 470 or more & - \\ \cline{2-6}  & & Cutting edge (polycrystalline diamond DP) & Cutting edge & & & & \\ \cline{2-6}  & & (polycrystalline diamond DP) & 776 & 0.2 & - & 4.2–8 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Basic information about the machine tool and its material. \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Direction of Loading in**} & **Young’s Modulus/MPa/  
of the values of the cutting force components depends on the number of cutting edges that are engaged in the cut, and other cutting conditions. The resulting cutting force is the vector sum of the individual components of the forces acting on the workpiece. Moment components are generated in a similar way by the real interaction of the cutter and the workpiece, see [25]. The time records of the forces in the direction of the axes of the Cartesian coordinate system (Fx, Fy, and Fz/N/) and the moments around these axes (Mx, My, and Mz/Nm/) were measured during the milling. The resulting forces and moments were obtained by vector summing the corresponding quantities. These are of stochastic/probabilistic character, i.e., they are variables with natural variability. A KISTLER type 9129 AA piezoelectric three-component dynamometer was used, see [26], to measure the forces and moments of force and moment effects during milling. A KISTLER type 9129 AA is a 'universal' dynamometer with a high natural frequency, main dimensions of 150 \(\times\) 107 \(\times\) 32 mm, an accuracy of \(\leq\)\(\pm\)2% of the measured range, and a maximum measuring range of \(\pm\)10 kN. Setup of this dynamometer enables accurate enough measurement of highly dynamic forces and guarantees very small influences of thermal effects [26]. Real-time force data from the dynamometer were transferred to a 5070A charge amplifier suitable for measurement with piezoelectric dynamometers or force plates. The signal was then sent to the data acquisition system DAQ BOX 5697A1. DAQ BOX 5697A1 is used for interfacing and controlling charge amplifiers and signal conditioners in general, as well as for cutting force applications using one or more component sensors and dynamometers, see [27]. Furthermore, it is processed using DynoWare software, which is capable of retrieving the necessary data at any time, and using them for further analysis.