To bond a golf club head to the shaft
with enough strength to withstand a golfer's swing and impact with the ball,
three companies co-operated to combine a two-component structural adhesive with
a volumetric epoxy dispensing system.
The competition to produce a top-quality
metalwood golf club is every bit a fierce as the competition on the course. One
manufacturer, Taylor Made Golf Co., has
developed a manufacturing process that combines a high performance adhesive
with a state-of-the-art epoxy dispensing system.
The Taylor Made design staff, the Sealant
Equipment & Engineering Inc. dispensing equipment supplier and the adhesive
formulator Ciba-Geigy have co-operated to make the old threaded connection
between the club and shaft a technique of the past.
to the Club
A key facet in manufacturing golf clubs is
the head-to-shaft-attachment. Because of the stress at this point, the club
needs a connection strong enough to withstand the golfer's swing and impact,
and durable enough to last for years.
To verify the durability of the product,
Taylor Made's manufacturing technique insures that the shaft-to-head connection
withstands a 5,500 psi pull apart test. No manufacturing method has proved as
effective as epoxy adhesive bonding in attaching the composite shaft to the
head, so the company implemented a rigorous testing process to select a quality
adhesive and a dispensing method.
Based on extensive research and testing,
the company chose a two component structural epoxy adhesive supplied by
Ciba-Geigy. The adhesive formulation, known as Araldite, is used in
applications for snow board, ski and golf industries due to its bond strength
and resistance to environmental conditions.
The company hit on Araldite after
comparative pull and impact tests of almost 50 additional epoxy formulations.
Performance testing, based on Taylor Made's stringent requirements, revealed
that the epoxy bond was only about 75% effective until the Araldite material
Once selected, the epoxy was mixed in small
batches by hand, dipping the shaft into the cup of mixed epoxy, then inserting
the shaft into the head - this almost guaranteed that they would not have 100%
bond area coverage. It also presented a housekeeping problem, in that the heads
would frequently require clean-up. Also, mixing to the specified ratio, 2.5
(Part A) to 1 (Part B), was difficult, frequently inconsistent and completely
operator dependent. The finished product, while better than most competitors',
was still less than perfect.
From both the production quantity and
quality standpoint, hand weighing, hand mixing and manually applying the epoxy
was unacceptable. At 1200 clubs per day, the company's demand was increasing,
so choosing an automated adhesive dispensing system with precision volumetric
positive displacement and shot size control became a priority. The company
began searching for equipment that would dispense the precise volume of
correctly and uniformly mixed, air free epoxy for each club and accurately bond
the components without mess and costly excess. It was determined that exactly
0.7cc of epoxy dispensed per club was needed. After testing other types of
dispense equipment, a
SeeFlo® 387 Bench Top
Meter / Mix / Dispense System was chosen supplied by
Sealant Equipment & Engineering Inc.
The SeeFlo® 387 is a positive
displacement volumetric dispensing system with precision shot size adjustment
capabilities. The system dispenses at a controlled mixed material flow rate
insuring that the mixed epoxy is not dispensed too quickly into the club head
and consequently trapping air. The SeeFlo® 387 system accurately dispenses
the required 0.7cc per shot, time after time, of the 2.5:1 ratio mixed
Using a disposable plastic motionless mixer
nozzle insures that solvent flushing is not required in the operation. Seal
modifications were made to the SeeFlo® 387 system to make it compatible
with the Araldite epoxy and meet the demanding production requirements. With
several SeeFlo® 387 dispense systems in place, production has increased
from 1200 to more than 4500 clubs per day and continues to rise.
In production, the operator positions the
club head under the SeeFlo® 387's disposable mixer nozzle and activates the
unit by pressing a foot pedal. The 387 then dispenses the precisely metered
The unique Snuf-Bak action of the
dispense valve ensures that the epoxy does not drip from the nozzle after the
dispense cycle is completed. The 387 system's A and B material holding tanks
were modified to include heat blankets to lower the epoxy's viscosity and
maintain the desired mixed epoxy cure time during cooler weather
Once the epoxy is applied, the bonded head
and shaft are placed in a fixture which pressure fits the parts together. The
finished clubs are tested to ensure that the bond meets the company's standards
for impact and tensile strength.
Today's Taylor Made System 2 driver, the
result of seven years of research and development, now sets a new standard for
golf club manufacturing. While continuously expanding production in the United
States, Taylor Made's sister company in Japan, now the home of some of the
greatest golf fans in the world, has entered the world-wide market. As the
company launches full production, similar equipment and manufacturing
techniques will be installed elsewhere.