SAMPE Journal - January/February 2023 - 47

* Platen temperature
* Tail heater temperature
* Platen and prepreg orientation (through
angle adjust)
* Interface normal pressure
* Pulling rate
The heated platens (Figure 3D) are detachable
by two pins (Figure 3E) to allow easy removal
and exchange of sample materials after testing.
Additionally, new platens with different profiles
and materials could be machined and equipped if
desired.
The pull-through fixture employs a specially
designed clamping system shown in Figure 4.
The five front facing holes on each platen (Figure
4A) allows for the insertion of multiple cartridge
heaters as well as a thermocouple to set and control
temperature of the platens at the desired value and,
when not in use, they can be thermally insulated
with insertable pins. The clamping bars (Figure
4B) affix to the platen pressing the prepreg into the
U-groove on the back of the platen to ensure the
prepreg is firmly fixed and slippage of the clamped
prepreg, with respect to the heated platen, is
avoided during testing. New clamping bars can be
manufactured with various heights as needed. Two
removable pins (Figure 4C) act to align the platen
to a polyether ether ketone (PEEK) block (Figure
4D) and secure it in place. The PEEK block is fixed
to the angle adjustment assembly (Figure 4E).
Since fiber orientations within a lamina
in complex formed laminates is seldom
unidirectional, the pull-through fixture platens can
be rotated to vary the prepreg fiber orientation with
respect to each other. The current design allows
for coarse and fine angle adjustment, indicated in
Figure 5. The platen assembly (Figure 5A) is fixed
to a keyed shaft (Figure 5B) that runs fully through
the lower clamping block (Figure 5C). The lower
clamping block in turn holds the shaft in axis
with the line of motion with the guide rail (Figure
5D) and has pre-machined holes in 15-degree
increments on the back face. The angle adjuster
wheel (Figure 5E) is attached to the shaft and a
retractable spring plunger (Figure 5F) is threaded
into the adjuster wheel. The retractable spring
pin rests in the machined holes on the back of the
lower clamping block. When the pin is retracted the
angle adjuster wheel is allowed to move freely and
the platen will rotate. The platen can therefore be
set in increments of 15 degrees, although this is the
coarse adjustment. To account for tolerance slop
between the retractable spring plunger and the prewww.
sampe.org
Figure 3. Pull-though fixture assembly overview
as mounted on a Mark-10 ESM303 (Mark-10 Corp.
Copiague, NY) universal test stand (A) universal
test stand, (B) force gauge, (C) wedge grips,
(D) platens, (E) removable pins, (F) angle adjust
assembly, (G) tail-heater assembly, (H) pneumatic
assembly, (I) load cell, (J) pressure regulators.
machined holes, the upper clamping block (Figure
5G) serves as fine coarse adjustment. The upper
clamping block can be tightened directly against
the shaft securing it in place with a frictional fit.
Application of consistent and steady normal
force to the clamping assembly is an important
design consideration. The pull-through fixture
makes use of a pneumatic air cylinder on the left
side of the fixture assembly. A detailed schematic
is presented in Figure 6. The Motion Controls
(Hartford, WI) tie rod air cylinder (Figure 6A part
number D70SENC SL1RA1) and threaded piston
conical adapter (Figure 6B) are actuated by a 5/2
air directional control valve (Figure 6C). When
supplied, the piston conical adapter contacts the
load cell dimple plate (Figure 6D). The load cell
dimple plate accounts for potential misalignment
as the piston strikes the plate, with the dimple
acting to self-center the tie rod of the piston. A
Figure 4. Clamping assembly (A) platens, (B)
clamping bars, (C) removable pins, (D) PEEK
block, (E) angle adjust assembly.
JANUARY FEBRUARY 2023
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SAMPE JOURNAL | 47
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SAMPE Journal - January/February 2023

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