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H I G H - P E R F O R M A N C E C O M P O S I T E S
FEATURE/MACHINING UPDATE
L E A R N M O R E
@
w w w. c o m p o s i t e s w o r l d . c o m
Read this article online at
short.compositesworld.com/1shotdrill.
Read more about how tool design and
micropecking affect drill tool performance in
"Hole ambitions? Optimize! Customize!" See
HPC September 2012 (p. 44) or visit
short.compositesworld.com/HJ0tdGm3.
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DR. DONALD F. ADAMS, PRESIDENT
STANDS BEHIND EVERY FIXTURE WE SELL
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Combined Loading Compression
Test Fixture ASTM D 6641
Short Beam Shear Test
Fixture ASTM D 2344
Iosipescu Shear Test
Fixture ASTM D 5379
Boeing Modified D 695
Compression Test Fixture
Compress Subpress
ASTM D 695
2960 E. Millcreek Canyon Road
Salt Lake City, UT 84109
Phone (801) 484.5055
Fax (801) 484.6008
email: wtf@wyomingtestfixtures.com
www.wyomingtestfixtures.com
Dr. Donald F. Adams
President
45 years of
Composite Testing Experience
W
T
F
yoming
est
ixtures
INC.
composite was the frst material in the
stack, but after much study, found it
doesn't matter where the composite is
because the hole diameters of the com-
posite are consistently smaller than in
the metal. Therefore, the Micro Reamer
only removes encroaching fbers and
burrs from the composite, and does not
remove metal.
That said, the metal is most often posi-
tioned at the bottom of the drill stack as
reinforcement for the composite struc-
ture. Metal chips that aren't successfully
evacuated can leave scratches (typically
1 mm deep) in the composite hole's
sidewall. Mueller-Hummel says, "This
is no longer an issue because the Micro
Reamer removes all of these scratches."
Status and qualifications
Mapal has demonstrated that, at lower
speeds and higher feed rates, the new
drill tool can cut H8 holes in one shot,
without MQL, for CFRP/CFRP and CFRP/
aluminum stacks. "We can also drill H8
holes in CFRP/titanium and aluminum/
CFRP/titanium stacks in a single opera-
tion, but," Mueller-Hummel concedes,
"we have to use MQL." However, he adds
that his team has developed a new tool
that works with titanium and is now re-
fning it to eliminate lubricant.
Nonetheless, Mapal's tool design and
drilling regime has achieved qualifca-
tion at six OEMs and Tier 1 suppliers and
is in the beginning stages with multiple
others. And the potential for savings is
signifcant. Mueller-Hummel reports,
"We have another customer working on a
large airframe drilling CFRP/aluminum
stacks in four to fve steps, requiring 30
minutes per hole and ending up with
very poor quality. Our trials so far have
reduced drill time to two minutes with an
H8 quality in one shot and no MQL."
Hole clean-up
The Micro Reamer on
Mapal's new drill tool
grinds away burrs and
scratches (see photo
left) leaving a high-
quality hole that is within
tolerance (right).
Conventional
Drill
MAPAL
Stacked
Drill
CFRP
CFRP
0514HPC_MachiningUpdate-OK.indd 54 4/22/2014 3:23:23 PM