# Evaluation of Non-Planar Tool Interaction in Milling of Shaped Surfaces Using a Copy Milling Cutter
## 4 Discussion  
The specimen used for the experiment represented a shape complex surface precisely due to showing the non-planar interaction between the tool and the machined surface. The results of the experiment showed the possibilities of evaluating this interaction and outputs that can be obtained by extracting different data from the point of contact between the tool and the machined surface. This was an assessment of the effective tool diameter, area, and volume parameter at the cutter engagement point.  
The experiment demonstrated the importance of applying the CAM system due to the variability in the use of possible milling strategies. Constant Z milling strategy was the most suitable in terms of surface quality and residual material displayed in the CAM system with respect to the shape area.  
The toolpaths generated in the SolidCAM corresponded to the toolpaths in the manufacturing process. It is therefore possible to conclude that the SolidCAM is suitable for the production of parts with shaped surfaces.  
Different finishing milling strategies with a defined geometry of the cutting edges of the tools impact the selection of the optimal milling strategy and allow for the prediction of machining errors as well as the amount of machining in the form of residual material that remains after the given strategy.  
The experiment proposed a methodology for comprehensive assessment of the area of the tool's engagement with the machined surface using Boolean operations, where it is difficult to analyse its distribution in terms of size, area, or volume.  
The selection of the milling strategy intended for finishing operations considered the size of the chip removal, which was defined by the milling cutter at the point of contact between the tool and the workpiece, which manifested itself in the form of changing maximum and minimum of the effective diameter of the tool, as well as considering the parameters of the chip in the form of the volume of material removed and surfaces.  
In the case of the evaluation of shape deviations, it can be concluded that using the constant Z strategy was conditioned by the display of the smallest amount of the area of residual material after milling compared to the Linear and Constant step over strategies, when the deviation in the form of undercutting by more than \(-\)0.15 mm was not exceeded.  
The negative deviations obtained by the scanning method were achieved due to machining near the centre of the tool, which was affected by the changing effective diameter of the tool.  
Larger distortion could be seen in the places where the tool interacted with the machined surface and in places near the boundary corners or corner areas. Based on the experiments, the number of places listed was 5-8.  
The aim of the contribution was to clarify the changing effective diameter of the tool with respect to the curvature of the machined surface and that in the specific point of contact of the tool with the surface. This experiment also points to the obtained information about the area and volume of the cutting surface at the point of contact of the tool with the workpiece, and identifies the cut points located at the output of the area cutter.