This trial was performed on a CNC Vertical Machining Center with a CT40 taper. Identical tool paths, spindle speeds, feed rates, material conditions, holding devices, coolant delivery, end mills and chip loads were utilized to isolate the performance of these tool holding technologies. The test cuts were in 4140 Prehard (30-32 Rc) using 3 flute uncoated carbide center cutting end mills. The identical tool paths involved a variety of cutting directions.
The most significant comparison between
these tool holding technologies
is in the area of tool life. The endmill
in the ShrinkFIT toolholder showed
dramatically less wear (photos) compared
to the endmill used in the collet
chuck (note the fractured surface).
Our results back up other reports that
ShrinkFIT allows 4 to 7 times the tool
life of other tool holding technologies.
In our tests there was significant fretting
on the taper of the ER collet chuck
while there was virtually no fretting on
the ShrinkFIT holder (visible in photo
above). This was attributed to the
superior wear characteristics of H-13
tool steel ovER8620.
During our four machining test passes of .125” depth of cut, the shrink fit tool holder required less spindle load than the ER collet chuck tool holder. The increased rigidity of shrink-fit created a more balanced chip load during cutting. This was observed in a better machining sound.
While both technologies have their place, machining
using ShrinkFIT is a significant improvement
over ER collet chuck technology. ShrinkFIT has
advantages in tool life, cutting ability, surface finish,
and produces less wear-and tear on the toolholder
taper and spindle bearings.