Page 60 - June

PROFESSIONAL ADVICE

The Steadyline system can enable typical long-overhang operations to be performed at
least twice as fast as with non-damped tools while enhancing part surface finish, extending tool
life, and reducing stress on the machine tool. Passive/dynamic vibration damping technology
can make it possible to accomplish certain applications,
such as some uses of tool lengths of up to 10 times bar
diameter, that would not otherwise be possible even at
minimal machining parameters.

Dynamic / Passive Vibration Operating principles

Figures 4 and 5 show how the Steadyline
Dynamic / Passive Vibration Management System
works. In Figure 4, vibration-related characteristics
of a traditional monoblock holder include mass
(M1), stiffness (K1) and intrinsic vibration damping
characteristic (K'1). The characteristics are combined
into the MKK 'system. During machining, the cutting
force Fe creates movement (vibration) in the holder.
When using the Steadyline system (Figure 5), the
following characteristics of the second MKK 'system are
added: mass M2, stiffness K12 and K'12 density. The
natural frequency of the MKK 'S2 system corresponds to
the original MKK' system, it resonates in antiphase with
unwanted vibration, dampening energy and vibration.
In the Steadyline system, the shock absorbing mass
is located at the front of the holder, where it is most Fig. 3.
likely to flex. Mass can instantly dampen vibration that
propagates from the cutting edge to the holder body.
The Steadyline system also includes short, compact GL cutting heads that position the cutting
edge close to the damping mass for maximum vibration damping. The system is suitable for a
variety of operations and is especially useful in milling (contouring, grooving and pocketing),
turning, and rough and fine boring.

Application Comparisons
A good example of the Steadyline system’s effectiveness involved a difficult boring
operation in 42CrMo4 steel where a cylindrical 105.8 mm bore was enlarged to a conical 129
mm bore in five roughing passes at a 3 mm depth of cut decreasing to 0 mm depth. With an
80 mm dia. bar, the initial cutting length was 600 mm, representing an extended tool length-
to-diameter ratio of 7.5. Roughing was accomplished at a feed rate of 0.3 mm/rev and cutting
speed of 157 m/min. Pre-finishing to a final 130 mm diameter took place at 0.5 mm depth of
cut, 0.2 mm/rev feed rate, and a cutting speed of 200 m/min. Even though the bulk of the

60 Stanochniy park