SEEMAN COMPOSITE RESIN INFUSION MOLDING PROCESS (SCRIMP) TECHNOLOGIES
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| Overview: | The
Seeman Composites Resin Infusion Molding Process (SCRIMP) is a
vacuum-assisted resin transfer molding process that produces parts excellent
for marine, aerospace, transportation, and infrastructure applications.
The process is a proven method of producing high-quality composite parts
made from a wide range of fiber and resin combinations. All commercial
fibers, core materials, and any resin in the range of 50 centipoise to
1000 centipoise will “SCRIMP” with outstanding results. The process can be
run at room or elevated temperatures. SCRIMP can produce large (2,000 sq.
ft.) parts, using both single skin and cored construction, and highly
complex three-dimensional trussed parts weighing up to 3,000 lbs. The
resulting composite material properties directly compare to properties
that had only been achievable in highly controlled expensive autoclave
processes.
The SCRIMP process is inherently repeatable. Once equilibrium resin content is achieved (55% to 60% fiber volume, depending on fabric architecture), the process stops. Aerospace grade quality is ensured by first eliminating all air voids before the resin is infused, enabling the fabric pre-form to act as an effective breather layer. As the resin is infused, it travels in controlled waves that work to completely wet out the reinforcing fibers and eliminate any voids that could be created by the volatile organic compounds (VOCs) emitted by the resin during the cure cycle. The process has been used to infuse laminates up to 6 inches thick with the same high-quality results as a simple 1/8 inch laminate. The Navy has extensively tested SCRIMP laminates and has concluded that the void content can not be detected with standard ASTM methods. With or without a gel coat, composites produced using SCRIMP exhibit pinhole-free surfaces. The Navy has developed prototypes of varying structures, such as ship’s masts, Navy Seal submarines, and sensor systems. The SCRIMP process also is being used to make sailboats, railcar bodies, intermodal shipping containers, bridge decks, windmill blades, and pilings, among other applications. One example of the application of the SCRIMP process is the Hardshaft manufacturing process. The process is used to manufacture marine construction products, such as fiberglass tubular pilings and marine fender panels. The process has extreme versatility and can produce pilings of any size up to 300 feet long and six feet in diameter. Benefits specific to the Hardshaft application are:
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| Compliance Benefit: | Due to
significant reductions in emissions of VOCs and other air pollutants, the
SCRIMP closed system may decrease the need for an air permit under 40
CFR 70 and 40 CFR 71. In addition, smaller amounts of hazardous materials (i.e.,
solvent) are required for the SCRIMP system. As a result, the possibility
that the facility would meet any of the reporting thresholds of SARA Title
III (40 CFR 300, 355, 370, and 372) is decreased.
The compliance benefits listed here are only meant to be used as general guidelines and are not meant to be strictly interpreted. Actual compliance benefits will vary depending on the factors involved, e.g., the amount of workload involved. | ||||||||||||
| Materials Compatibility: | No
materials compatibility issues were identified.
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| Safety and Health: | The
SCRIMP process increases worker safety by reducing VOC emissions. Consult
your local industrial health specialist, your local health and safety
personnel, and the appropriate MSDS prior to implementing this technology.
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| Benefits: |
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| Disadvantages: |
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| Economic Analysis: | The
SCRIMP process is a patented system licensed for $25,000. Hand layup, the
conventional method of marine construction, is a labor-intensive process
resulting in a product with relatively high porosity and low fiber content
that reduces strength and stiffness. The unit cost per pound of labor and
materials for a generalized structural configuration, based on an
assumption of $40/hour shipyard labor, is less than $10/lb. The SCRIMP
process may decline in price in the future, as it is currently being used
for producing prototypes in many applications. The SCRIMP process,
currently at a comparable cost, produces a higher quality product while
emitting fewer VOCs, which can endanger workers. Currently, the cost of
using the SCRIMP process is less than $10/lb.
Based on the construction of four, one-half scale midship sections of a medium-sized 280-ft., 1200-ton naval combatant, the SCRIMP process produced a hull section weighing slightly under 23,000 pounds, including 13,000 pounds of glass and 7,000 pounds of resin. The production time for fabricating the hull section was 3,154 labor hours. Another example of an application that has been used more widely is pilings. The following assumptions were used to compare the cost of Hardcore pilings using the SCRIMP process to conventional CCA pilings: Assumptions:
Although the Hardcore pilings cost more initially than conventional pilings, the costs involved in replacing the shorter-lifespan, conventional pilings increase the overall costs of conventional pilings significantly. In the longterm, Hardcore pilings are more cost effective. Click here to View an Active Spreadsheet for this Economic Analysis and Enter Your Own Values. To return from the Active Spreadsheet, click the Back arrow in the Tool Bar. | ||||||||||||
| NSN/MSDS: | None identified.
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| Approving Authority: | Appropriate authority for making process changes should always be sought and obtained prior to procuring or implementing any of the technology identified herein.
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| Points of Contact: | For more information | ||||||||||||
| Vendors: | This is not meant to be a complete list, as there may be
other suppliers of this type of equipment.
TPI Composites, Inc. | ||||||||||||
| Sources: | Research Release "Low Cost,
High Quality composite Ship Structures Technology Demonstrated,"
Headquarters, David Taylor Model Basin, Naval Surface Warfare Center,
Carderock Division, Bethesda, MD, May 1993. Nguyen, Loc D., Thomas Juska, and J. Steven Mayes, "Evaluation of Low Cost Manufacturing Technologies for Large Scale Composite Ship Structures," Naval Surface Warfare Center, Carderock Division, West Bethesda, MD, Presented to 38th Structures, Structural Dynamics, and Materials Conference and Exhibit, AIAA/ASME/AHS Adaptive Structures Forum, Kissimmee, FL, April 7-10, 1997. | ||||||||||||
| Supplemental: | Picture of Seeman
Composite Resin Infusion Molding Process (Scrimp) Technologies
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