Today's Industrial Products and Solutions May 2019 | Page 28

HIGH TORQUE INCEPTION / TOOLING COST REVELA-
TION:
A few years ago, Boeing (Seattle, WA) contacted
one of their tooling manufacturers, Briney Tooling
Systems (Bad Axe, MI), a leading supplier of CNC
tool holders and shrink fit tooling systems in North
America, reporting that they had performed test-
ing that revealed a flaw in the V-flange tooling they
were using. Requesting a solution, Briney reached
out to JM Performance Products, Inc. (JMPP: Fairport
Harbor, OH / formerly J&M Machine) to elicit their as-
sistance in resolving the problem Boeing described.
In turn, within the following week, JMPP began an
intrinsic investigation and ultimately designed a gage
that mirrors the interior grind of a CNC spindle. This
gage measures movement or growth of the tool-
holder taper down to 7.5 millionths inch in diameter.
JMPP identified that the essential flaw, the invisible
problem plaguing CNC manufacturers, as toolholder
expansion. Using their gage to perform extensive
testing, JMPP proved that toolholder expansion is
caused by the installation of a standard retention
knob into a V-Flange holder.
Briney had reported expansion of their holders with
as little as 13 ft./lbs. of torque during retention knob
installation. This expansion creates a bulge in the
holder at the small end, causing the holder to make
contact with the small end instead of the large end.
This effectively reverses the way the toolholder is de-
signed to fit the spindle, allowing the holder to move
randomly within the spindle. This movement results
in a loss of contact between the spindle and the tool-
holder, and causes a laundry list of issues: vibration
and chatter, excessive run-out, poor finishes, short-
ened tool life, high power consumption, excessive
spindle wear, need to slow down, and the need to
reduce the depth of cuts.
Using the taper shank test fixture, JMPP redesigned
the knobs, finally reaching a design that eliminated
or substantially eliminated toolholder expansion.
Their patented High Torque retention knobs are de-
signed to thread deeper into the bore of the holder
where there is a thicker cross-section of material to
resist deformation.
Boeing’s major complaint was associated with the
26
TIPS Magazine • May 2019
vibration and chatter–that was causing tolerance
and finish issues on extremely expensive parts. The
introduction of the High Torque knobs effectively
eliminated the chatter issues. Once the knobs were
made available to the general milling population,
JMPP began to get feedback from customers that
served to emphasize how rampant and detrimental
a problem toolholder expansion represented to the
manufacturing community.
CLIENT COST CONTAINMENT / TOOLING CHAL-
LENGE PROFILE:
Schuster Mechanical, LLC (Detroit, MI), a growing
CNC job shop focused on auto test equipment, was
investigating new CNC machine investments which
included TRAK 2op and TRAK LMP. The TRAK 2op is
the first portable (2.5’ x 4’ footprint) VMC to focus on
Second Operations Work, featuring an 8-station tool
changer, and 10,000 RPM spindle. The TRAK LMP
VMC is a low volume/high mix production system
that incorporates technologies to markedly reduce
the changeover times that plague high-mix, low-vol-
ume shops.
Owner Robert Schuster wanted to proactively en-
sure that his spindle cartridge would last as long as
possible to maximize the dependability and pro-
ductivity of the new machining centers. Schuster
engaged with JMPP’s sales engineering personnel at
an industry trade show, who showed him how their
knob’s threads ran deeper into the holder–causing
less distortion at the small end of the taper. Schuster
was immediately impressed that his holders were
not damaged by the expansion caused by the stan-
dard knobs, and could still be used in production
with the High Torque knobs–with no spindle damage
occurring.
Initially, Schuster was considering implementing
an HSK toolholder system, but found that it was an
expensive system that had too many limitations to
justify conversion from V-Flange. The HSK design
features a cup-shaped holder that doesn’t provide a
long reach, the socket is shallow, and the walls are
thin. The High Torque knobs maintain spindle/taper
contact, with the benefit of the more affordable
V-Flange CAT/BT holder system.
Subsequently, Schuster determined JMPP’s BT30
knobs (JM31109HT) would be a more cost-effective