RP055
- Analysis and Control of the Resin Transfer Molding Process
Using In-Mold Sensors; Ford Motor Company, D.J.Melotik, M.Czaplicki,
T.J.Whalen and D.R.Day
ABSTRACT
Interest in
the potential use of resin matrix composites for structural
automotive components has grown dramatically in the last five
years. This has been evidenced by the formation of an Automotive
Composites Consortium composed of General Motors, the Chrysler
Corporation and Ford Motor Company to investigate these materials.
Efforts are underway within these member companies to study
material properties, processing procedures, and energy management
phenomena in order to allow the design of viable structural
vehicle components (eg: crossmembers, bumper beams, and front-end
rails) utilizing Resin Transfer Molding (RTM).
While progress
is being made in all these areas of investigation, it is extremely
important that processing feasibility be adequately understood
and demonstrated. It is particularly necessary to understand
and control the curing process in the mold in order to project
acceptable cycle times. In this investigation a temperature,
pressure, and cure (dielectric) sensor was mounted in the surface
of an RTM mold. The cure behavior, mainly time to viscosity
minumum and vitrification (determined from the dielectric data),
was monitored as a function of various process parameters.
These included mold temperature, resin presssure, resin chemistry,
part thickness, and reinforcing fiber fraction. Results of
cure sensitivity to the various controlled parameters and experiments
with controlled press opening are presented. Dielectric sensor
output was shown to be an excellent indicator for controlling
press opening based on the vitrification event.
Return
to Top
RP124
- Resin Flow Front Reconstruction with Applications to Resin
Transfer Molding (RTM), U.S.Army Research Laboratory, Shawn
M. Walsh; CDEF Associates, C.E.Freese
ABSTRACT
The development
of a new class of sensors has permitted composite materials
researchers and engineers alike to obtain further insight on
both the process and material used in composite fabrication.
This sensor data can be used in several critical capacities,
including fundamental observation of process/material phenomena
and interaction, validation of increasingly sophisticated process
simulations, and as a source of feedback in an on-line process
control system. However, if one is to fully realize the potential
of sensor data, provisions must be made to manipulate it as
repidly and as meaningfully as possible. This paper presents
the results of a recently developed numerical smoothing algorithm
that, upon application to a field of retrieved sensor data,
is capable of substantially enhancing visualization of resin
flow during the resin transfer molding (RTM) process. This
methodology will directly impact both observation of "wet" composite
processes as well as provide a stream of sufficiently rich
data to calculate and implement intelligent control decisions.
Return
to Top
RP058
- In-Process RIM Analysis with Microdielectric Sensors; Micromet
Instruments, Inc., David D. Shepard, Huan L. Lee and David
R. Day
ABSTRACT
Conventional
thermoset reactions are studied dynamically by classical laboratory
techniques such as FTIR. However, these methods are not very
useful for high speed systems such as RIM where gelation can
occur within three seconds and cure is complete by thirty seconds.
Recently developed Microdielectric sensors and associated electronics
can be operated with high sampling rates so that a measurement
is recorded every 10 milliseconds. This paper will first review
recent developments in microdielectric data reduction and high
speed measurement capabilities. Several examples of in-mold
RIM dielectric data will be presented. Critical points in the
RIM reaction, such as time for resin to reach the far recesses
of the mold, end of cure, and de-mold will be described utilizing
the dielectric response. Finally, several methods for process
control utilizing the microdielectric response are proposed.
Return
to Top
RP062
- Some Criteria for SRIM Processing of Large Parts; Shell
Development, W.Richard Schmeal, George G. Viola, and Jerry
Scrivo
ABSTRACT
Processing large
parts by Structural Reaction Injection Molding (SRIM) features
the conflicting requirements that the mold be filled prior
to gelation and that quick and relatively complete reaction
be achieved to allow successful post processing. Resins shoiuld
be amenable to snap cure. In the case of polyisocyanurates,
this means slow reaction to form urethanes followed by fast
isocyanate trimerization. The mold, preform, and resin should
be designed so that heat is transferred in ways which hinder
early reaction of the advancing resin flow front yet enhance
later reactivity. Some guidelines are presented.
Return
to Top
RP129
- Resin Flow Front and Cure Detection in RTM and other Resin
Infusion Processes, Holometrix Micromet, David D. Shepard
ABSTRACT
Monitoring of
the resin flow during the part filling of resin infusion processes
is critical because the flow is responsible for the final mechanical
properties of the part. A resin flow front analysis system
been introduced based on technology developed by the U. S.
Army Research Laboratory. The system is used for the in-process
monitoring of resin flow and cure in Resin Transfer Molding
(RTM), SCRIMPÂ, vacuum assisted RTM, and other resin infusion
processes. The system consists of a sensor grid, an electronics
package designed to rapidly interrogate the grid, and a Windows-based
software program to control, record, and display the sensor
data. The system measures the electrical properties at intersecting
nodes of conductive wires or fibers that are manually laid
out in the mold to form a grid pattern. When resin reaches
each node, the electrical properties of that node will change
and are recorded by the system to provides a map of the part
filling process. The subsequent resin gel and onset of cure
can also be detected. The data obtained with the system is
not as sensitive to the end of cure as traditional AC resistance
measurements.
Return
to Top
RP131 - Large
Scale Implementation of Flow and Cure Sensing in a Thermoset Resin
Infused Composite Structure, Roderic Don, Karl Bernetich, and John
W. Gillespie, Jr., University of Delaware's Center for Composite
Materials; Bruce K. Fink, U.S. Army Research Lab; Michael Louderback,
Northrop Grumman Corporation
ABSTRACT
A highly successful
demonstration of resin flow and cure sensing using the U.S.
Army Research Lab's patented SMARTweave imbedded sensor technology
was done on an Advanced Technology Transit Bus (ATTB) subcomponent
at Northop Grummans's El Segundo plant. The part was fabricated
using single-sided tooling, and consisted of a multi-layered
woven preform, sandwiched around a foam core, which was infused
with resin in a modified VARTM-type process. The flow of resin
into portions of the part not visible to the eye was readily
detected. This experiment was the largest application to date
of the SMARTweave technology, and was performed by researchers
from the University of Delaware's Center for Composite Materials.
Return
to Top
|
