Many golfers believe the shaft makes the club. Graphite composite shafts are more popular than ever,...

1. Graphite Golf Clubs & Composite Shaft Technology
Many golfers believe the shaft makes the club. Graphite composite shafts are more popular than
ever, particularly for the driver, or #1 wood. Design variables, such as quantity of fiber, number of
layers of fiber and orientation of the fiber in each layer should be considered and
http://www.golfandcountry.ch/news/swiss-scene/swiss-scene-detailansicht/browse/10/article/2-siege-
sherlyn-popelka-bestand-solh-
im-test.html?tx_ttnews[backPid]=6&cHash=65bcfd2f5371cb765bb2ad75e583f802 will define the
lay-up process as well as the attributes and performance of a finished shaft. Four segments of a
manufacturing process will be addressed in this overview. They are, material preparation, lay-up
cure, cut grind and finishing.
Graphite Material and Preparation
Graphite fiber material which has been impregnated with resin is called "graphite prepreg". This
material, commonly called broadgoods, will typically arrive from the vendor in a roll of poly about
three feet wide. The poly has the prepreg fiber laid onto it. The strands of fiber are all oriented to
meet design criteria when laid on the poly.
The fiber preparation is to orient the broadgoods according to the predetermined angle and cut a
triangle shape from the sheet. This triangle shape may be called a pennant or flag by some
manufacturers. The orientation of the fibers for each layer, or ply, is determined by the design. The
number of layers, or plies is also determined by the design for each shaft.

2. Fiber Lay-up and Cure Cycle for the Graphite
Prepreg
A mandrel is a tool which is a mold form for
the inside of the hollow golf shaft. Think of it
as a solid metal pencil-like tool which is over
four feet long and slightly tapered. The
mandrel surface is treated with mold release
and placed into a rotating machine where the
fiber triangles are applied.
The cut graphite triangles are sequenced by
size and fiber orientation for each ply, as
called out by the shaft design. The triangle for
the first layer is oriented on the mandrel and
the mandrel is rotated while the graphite fiber
triangle is compacted around the mandrel.
This process is repeated until all of the fiber
triangles are applied in the sequence noted in
the design. After all of the plies have been
compacted on the mandrel, the layup is then
over-wrapped to hold all of the fibers in
proper position during cure. At least one manufacturer uses http://www.usatoday.com/sports/golf/
cellophane for this over-wrap as it creates a vacuum effect during the cure and mandrel expansion.
Note: The strength of each fiber layer, as well as the orientation of the fiber in each layer, will
determine the stiffness and torque (resistance to torsion) of the completed shaft.
The cure cycle depends on the resin utilized in the design as well as the thickness of the fiber build
up. A typical cure cycle for a graphite golf shaft might be around 300-325 degrees F, for two hours
or more at the elevated temperature. Upon completion of the cure cycle and removal from the oven,
the over-wrap is removed and the mandrel is extracted from the cured shaft.
Cut to Length and Surface Grinding of the Graphite Shaft
Once the mandrel extraction is complete, the cured shaft is placed into a cut off saw. Typically this
saw will position the shaft in the machine and cut the shaft to length, cutting both ends at the same
time. Club makers, as well as some shaft manufacturers, call this process "trimming".
The shaft is then removed from the saw and placed into a grinding station. The external surface of
the shaft is then ground smooth, to the proper outside dimensions. This is typically accomplished
utilizing a pair of opposing grinding heads.
Final Finishing and Inspection of the Graphite Golf Shaft
Inspection of the shaft should be performed throughout the remainder of the process. The surface
should be inspected for any voids or imperfections and the shaft should also be tested for the proper
frequency that is associated with the stiffness for which the shaft was designed.

3. The final finishing of the shaft starts with painting
and passing through a bake cycle for curing. Once
the painted shaft passes inspection it will have the
graphics applied and finally the shaft is sealed and
given one final inspection prior to packaging and
shipment.
Graphite Composite Clubs a Part of the Evolution
of Golf Equipment
The game of golf and the equipment used has
evolved tremendously over the years. In the last
25 or more years, graphite golf club shafts have
been a part of that evolution. Although the details
of the fabrication processes for graphite shafts
may vary from one manufacturer to another, this
basic overview should provide a general understanding as to how graphite shafts are manufactured.
An article is available which explains golf swing speed and shaft stiffness that may also be of
interest, as well as the article about the physics of swing tempo.
References:
True Temper Sports website, last checked 8/25/09
Graphite Design International, Inc.website, last checked 8/25/09