Calculation of Side-Milling Time

Firstly, the part's exterior perimeter (*Pext*) is calculated, considering the part's length and width values. Secondly, the estimated number of roughing passes (*No. R.P.*) is defined. This is calculated as shown in Equation (1), considering part thickness (*t*, in mm) and the depth of cut (*ap*, in mm).

$$\text{No. }\_{\text{R.P.}} = (\frac{t}{a\_{\text{e}}}) \tag{1}$$

The value obtained from the calculation of (1) should be rounded up, being equal to an integer. Moreover, the number of finishing passes (*No. F.P.*) are also calculated, as shown by the Equation (2), considering part thickness and the tool diameter (*Øtool*).

$$\text{No.}\,\_{F.P.} = (\frac{t}{0.5 \times \mathcal{O}\_{t \times cl}}) \tag{2}$$

With both the values of the number of finishing (*No. F.P.*) and roughing (*No. R.P.*) passes, and the values for the exterior perimeter (*Pext*) and the feed rate (*Vf*, in mm/min), the machining time for side-milling (*M.T. S.M*., in minutes) could be calculated, as shown by Equation (3).

$$M.T.\_{S.M.} = \frac{P\_{\text{ext}} \times (No.\_{R.P.} + No.\_{F.P.})}{V\_f} \tag{3}$$

For this kind of operation, the chosen tool diameter usually depends on the thickness of the machined part, as presented in Table 4.

**Table 4.** Different tool diameters chosen in function of part's thickness.


Regarding feed rate value, it is chosen based on the machined material and on the current cutting length. For lower cutting lengths the value of feed rate will be lower and, consequently, for higher cutting lengths, the value of feed rate could reach up to 3000 mm/min, for high-performance tools.
