The dimensions of the cutting edges of the drills, used in experimental, drilling processes, in which the surplus were not predrilled, are calculable as seen in (1), depending on the geometry of the tip of the drill, as shown in Figure 4 according to predrilling diameters and drill point angle:
The uncut chip height ([h.sub.D]) can be calculated based on the feed rate ([f.sub.z]) and point angle ([phi]) by using (2), in accordance with the geometry of the drill point, as shown in Figure 4.
Furthermore, point angle
controls burr height at the end of holes.
The High Speed Steel (HSS) industrial tools of diameter of2-6.5mm and point angle
of 90-130 were used.
The "point angle
" cultivars were Gn0270, Lc03-1137, Fn38, and Yz06-407, respectively.
Moreover, Figure 6 shows a comparison between the simulated d[B.sub.[phi]]/dt based on different values of ground reflection factors and the corresponding measured fields whereby the channel and the observation point angles
are set at 20[degrees] and 120[degrees], respectively.
from contact point to contact point, and from mesio-labio-incisal point angle to disto-labio-incisal point angle was noted using digital vernier caliper.
TABLE 2: MESIO-DISTAL WIDTH OF SIX ANTERIOR TEETH AT MESIO-LABIO-INCISAL POINT ANGLE
The magnetic flux density and the vertical electric filed behaviors versus the channel angle and observation point angle changes are shown in Figures 11 and 12, respectively.
In other words, whenever the observation point angle ([phi]) goes up to 90 degrees (at a constant value of [theta]), the values of vertical electric field and magnetic flux density drop, as shown in Figures 11 and 12, respectively.
In this paper, the experimental model is presented to predict the influence of twist drill point angles on the cutting forces to be presented based on MGGP method.
In order to prepare the training input data, firstly, the experiments were conducted to grind twenty twist drills with different drill point angles with Biglide parallel machine; the structure is as shown Figure 1 .