Example Of Moment Of Inertia Calculation - Yamaha YK-X Series User Manual

6-3

Example of moment of inertia calculation

Let's discuss an example in which the chuck and workpiece are at a position
offset by 10cm from the R-axis by a stay, as shown in Fig. 3-21. The moment of
inertia is calculated with the following three factors, assuming that the load mate-
rial is steel and its density ρ is 0.0078kg/cm
1) Moment of inertia of the stay
From Fig. 3-22, the weight of the
stay (Ws) is given as follows:
Ws = ρabc = 0.0078 × 12 × 2 × 2
The moment of inertia of the stay (Js) is then calculated from Eq. 3-7.
Js = 0.37 × (12
4cm
6cm
Workpiece
= 0.37 (kgf)
) + 0.37 × 5
2 2
+2
12 × 980
980
3-23
3
.
Stay
Chuck
4cm
Fig. 3-21
Center line
2cm
2cm
2
= 0.014 (kgfcmsec
CHAPTER 3 Installation
R-axis
2cm
2cm
R-axis
Fig. 3-22
2
)