|
S-Wrap in Deep Well
of Open Resin Bath |
In this
demonstration, H-shaped 3D braided
preform was successfully tailored to
the available die at Reichhold
company facility in Research
Triangle Park NC, allowing the
demonstration of pultrusion of a
moderately complex structural shape
from a near net shape braided
preform. Results yielded useful
material and showed significant
promise for future success in
pultrusion of net shape preforms in
structural shapes. |
H-section
polyethylene guide aids alignment |
The preform was
passed through a 3 Bar S-Wrap guide
set within a 20cm deep well at the
first point of entry to encourage
thorough wetting of the fibers. A
loosely fitting H-section
polyethylene guide was used to aid
in alignment of the flange and web
elements of the preform into those
in the die properly. |
|
3D
braided product exits pultrusion die |
The Die was roughly
32 inches long. Temperatures in the
die were maintained at 315 degrees F
near the entry, and at the exit.
Feed rates through the system was
set at 16in/min yielding a dwell
time in die of 2 min. Reichhold
31040-00 Urethane hybrid resin
system, with the addition of 20%
in-organic filler was used. |
|
Final pultruded
H-shape product |
The 3TEX 3BRAID
preform was designed to ascend
toward 63% fiber volume fraction (Vf)
over two stages. In the first stage
the preform contained a constant
axial fiber content, but reduced
braiding yarn sizes to
conservatively achieve Vf =57% to be
sure of successful pultrusion. In
the second stage the preform was
designed to reach a more aggressive
Vf=63%. Limited scaling and resin
rich areas indicated that the 63%
section of the preform was just
beneath the full die requirement.
One or 2 additional rovings would
have likely been appropriate. |
