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Last updated: January 2026
This directory lists 37 structural foam molding companies across the United States, from high-volume industrial equipment component manufacturers to specialized producers of large, structurally rigid enclosures.
Buyers are solving a range of problems, including manufacturing large, rigid plastic parts with excellent strength-to-weight ratios, consolidating multiple components into a single mold, and reducing tooling costs compared to conventional high-pressure molding. Key considerations often revolve around minimizing sink marks on cosmetic surfaces, ensuring uniform cellular core density throughout complex geometries, and managing part flatness over significant dimensions.
Suppliers in this space vary from those specializing in high-tonnage presses for very large, structural components like pallets or HVAC housings, to those offering gas-assist molding capabilities for internal coring and improved surface finish. Some are vertically integrated, providing design and tooling services, while others are contract manufacturers focused purely on molding, often catering to industries requiring specific material certifications or secondary operations.
Buyers should come prepared with detailed CAD models, material specifications (if known), anticipated annual volumes, and critical performance criteria such as load-bearing requirements or environmental exposure. Suppliers, in turn, expect clarity on cosmetic expectations (e.g., whether a painted finish is planned), tolerance requirements, and any specific post-molding processes, enabling them to provide accurate DFM feedback and quoting.
37 companies nationwide
Based in Houston, TX, Built With Foam specializes in creating custom foam products for the construction industry. They fabricate items such as shower bases, benches, curbs, sink basins, and domed ceilings, customizing products based on client specifications and designs.
Based in San Diego, CA, Custom Engineering Plastics (CEPI) specializes in designing and manufacturing a wide range of plastic parts. They offer structural foam molding, injection molding, and blow molding services. CEPI serves diverse industries including medical, aerospace, automotive, electronics, and consumer products, providing comprehensive solutions.
Based in Whiting, Indiana, Cooper Plastics is a custom plastic manufacturer specializing in thermoplastic materials. They directly provide structural foam injection molding services, alongside sheet extrusion, thermoforming, rotational, and blow molding. The company offers customized solutions to meet specific strength, weight, and material specifications.
Core Molding Technologies provides structural foam molding services, specializing in durable, lightweight components for parts requiring high strength-to-weight ratios and complex geometries. Headquartered in Columbus, Ohio, the company operates multiple US facilities, offering comprehensive molding solutions across various industries.
Based in Sterling Heights, MI, General Plastics specializes in polyurethane foam solutions. The company offers comprehensive services, from part design support to full production, utilizing their certified equipment to deliver finished components. They provide start-to-finish manufacturing for various industrial applications.
Grand Rapids Foam Technologies (GRFT) is a polyurethane foam manufacturer based in Grand Rapids, MI, with over 75 years of experience. They specialize in custom molded foam systems, including rigid urethane and self-skinning foam, for diverse industries. GRFT is ISO9001/2015 certified and FDA registered.
HFP is a manufacturing firm based in San Antonio, TX, providing engineered solutions for packaging and construction. The company specializes in shape-molded foam products, including cold chain coolers. HFP offers full-service design, manufacturing, and testing capabilities, supported by top-of-the-line equipment and a dedicated tool and die shop.
Based in Vancouver, WA, KASO Plastics provides comprehensive plastic injection molding services, including structural foam molding for larger projects. They also offer 3D printing, rapid prototyping, metal to plastic part conversion, and engineering services to support various manufacturing needs for their clients.
Mack Molding provides structural foam molding for large, complex parts, emphasizing strength, reduced weight, and cost-effective production. A vertically integrated manufacturing partner, they also offer plastic injection molding, design for manufacturing, large part molding, Class A painting, machining, and contract manufacturing.
Orozco Foam Molding Inc. specializes in providing foam molding services. Based in Stockton, CA, this company manufactures custom foam components for various industrial applications. Their expertise in foam molding indicates capability in producing parts suitable for structural integrity and lightweight design.
Osborne Industries, based in Osborne, KS, is a manufacturer specializing in advanced thermoset molding and plastics manufacturing. The company provides various molding processes, including Structural Foam Molding, Resin Transfer Molding (RTM), and Injection Molding. They offer custom composite part production for diverse industrial applications.
PSI Molded Plastics is a custom injection molder specializing in structural foam and gas assist molding for small to large parts. They provide in-house finishing, custom color matching, and value-add assembly. With US manufacturing facilities, PSI supports diverse production volumes.
Based in Weatherford, TX, RIM Manufacturing, LLC specializes in custom Reaction Injection Molding (RIM) for a wide range of parts, including structural foam. They provide comprehensive services from design and mold manufacturing to part production, secondary processing, painting, and assembly of thermoset polyurethane components.
Based in Pensacola, FL, Reliant Plastics offers custom plastic injection molding services, including structural foam molding, insert over-molding, and gas assist molding. They provide comprehensive manufacturing capabilities, working with various engineered resins and materials for industrial and commercial applications.
Based in Morgan Hill, CA, Rimnetics specializes in reaction injection molding (RIM) for structural parts, custom enclosures, and composite products. With over 30 years of experience, they serve industries including medical device, electronics, IT, and defense, offering lightweight and durable polyurethane solutions.
Romeo RIM is a manufacturer specializing in Reaction Injection Molding (RIM) technology, including Structural RIM. They produce high-quality, custom molded polyurethane and polymer components for diverse industrial applications. Their advanced manufacturing facility is located in Bruce Township, Michigan.
Based in Ohio, this company specializes in custom structural foam injection molding. They offer production services for creating large, durable custom plastic parts, serving industrial and commercial clients with their manufacturing capabilities in advanced plastic production processes.
Based in Jonesville, MI, Triple Diamond Plastics manufactures structural foam products, including durable collapsible storage containers, plastic pallets, and reusable transport packaging. Their USA-made solutions, crafted from 100% recycled HDPE, emphasize strength and sustainability, providing diverse industries with eco-friendly logistics management.
TranPak manufactures and distributes plastic pallets, bins, and crates. The company provides plastic molding services and product development, producing large structural parts such as custom pallets, mega bins, and liquid containers. They serve diverse industries, creating products from both recycled and virgin materials.
Ensinger Plastics provides structural foam injection molding services, utilizing MuCell® technology to create lightweight, precise, and durable plastic parts. They offer a wide range of high-performance materials and engineering solutions, serving diverse industries such as aerospace, medical, electronics, and mobility.
TPM, based in Hopkins, MN, offers flexible and innovative precision molding solutions for complex problems. The company specializes in injection, 2-shot, insert, and thermoset molding of highly engineered plastic components. They serve diverse markets including Automotive, Small Engine, Consumer, Industrial, Packaging, and Medical industries.
20/20 Custom Molded Plastics specializes in structural foam and structural web/gas assist molding. Operating facilities in Ohio, Indiana, and Georgia, the company provides custom high and low-pressure injection molding solutions. They integrate design, engineering, and quality control to achieve cost-effective manufacturing and superior part performance.
Based in Gainesville, TX, Advanced Pedestals, Ltd. (API) is a plastic manufacturing company specializing in custom rotational and injection molding. They provide comprehensive molding services, from engineering and design support to warehousing and shipping. API crafts durable plastic products for electric utility, agriculture, and industrial manufacturing applications, ensuring precise specifications.
Based in Franklin Park, IL, Cortina Tool & Molding is an American manufacturer established in 1969. They specialize in plastic molding services, including high-pressure foam molding, to produce quality parts with superior surface finishes. Cortina offers cost-effective manufacturing solutions from initial drawing through tooling and production.
DeKALB Molded Plastics is a custom structural foam molder based in Butler, IN, specializing in large, multi-nozzle plastic products. The company focuses on minimizing tooling and part costs while optimizing designs for functionality. With expertise in plastic processing, DeKALB serves markets such as medical housings, safety enclosures, and specialty material handling.
Based in DeForest, WI, EVCO Plastics is a global plastic injection molding company. They operate over 35 large-ton machines, ranging from 1,000 to 4,400 tons, across facilities in Wisconsin, Georgia, and Mexico. EVCO specializes in collaborating with clients to bring complex plastic projects to full form.
Based in Akron, OH, Ferriot Inc. provides structural foam molding and injection molding services. Their comprehensive capabilities extend from engineering and supply chain management through final production, including custom color, cosmetic finishing, and assembly for manufactured products.
Based in Rogers, AR, FM Corporation specializes in structural foam and high-pressure injection molding, producing parts from 5 oz to 75 lbs. Since 1980, this ISO 9001-2015 certified company offers comprehensive in-house finishing, assembly, and metal fabrication services from its 165,000 sq ft facility.
Based in Mount Pleasant, IA, Lomont Molding LLC is a plastic molding company specializing in structural foam molding. Established in 1982, they also provide injection molding, blow molding, over-molding, nitrogen gas molding, and in-mold decorating. Lomont delivers high-quality solutions nationwide.
Based in Norwalk, California, Petersen Molding Corporation is a custom plastic injection molder specializing in structural foam and standard injection molding services. With over 50 years of experience, the company provides comprehensive solutions from tooling and prototyping to assembly, overmolding, and finishing for various industries.
Based in Eagle, WI, Plastic Molded Concepts, Inc. specializes in advanced plastic injection molding. The company is known for its expertise in molding engineered resins, serving industrial and commercial clients. PMC provides comprehensive molding solutions, leveraging specialized techniques to produce high-quality, precision components for diverse applications.
Based in Corona, CA, Preproduction Plastics Inc. specializes in structural foam molding as an ISO 9001:2015 and UL certified company. This family-owned business provides comprehensive plastic molding services, including engineering design, in-house tooling, injection molding, gas assist, and gas counter pressure.
Based in Longmont, CO, PTA Plastics is an employee-owned custom plastic injection molder. They offer high-precision injection molding, DFM, and in-house moldmaking. Capabilities include gas-assist injection, cleanroom manufacturing, and process validation, serving various industries with ISO 9001:2015 and ISO 13485:2016 certifications.
Based in Georgetown, TX, R&D Molders specializes in manufacturing structural foam molding products. They also provide comprehensive injection and blow molding services, delivering custom plastic solutions. The company serves diverse industries like Medical, Industrial, Consumer Goods, Electronics, GSA/DOD, and Energy.
Based in Moreno Valley, CA, South Coast Foam Shapes specializes in producing custom foam components. The company provides a range of foam shaping and fabrication services, likely including structural foam molding to create lightweight yet durable parts for various industrial and commercial applications.
Texas Injection Molding, based in Houston, TX, provides custom plastic injection molding services for original equipment manufacturers and consumer products. The company offers decades of experience, product design assistance, and engineering services for developing plastic injection molded products, serving customers across the S.E. United States.
Universal Plastics specializes in advanced plastic injection molding services. The company offers a range of capabilities, including structural foam molding and gas assist molding. They serve various industries, prominently catering to medical sector customers. Located in Holyoke, MA, Universal Plastics provides custom manufacturing solutions.
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Achieving a smooth, Class A surface directly from structural foam molding is challenging due to the expanding foaming agent. Many buyers plan for secondary operations like painting, texture application, or in-mold decoration to hide swirl marks. Discuss your aesthetic requirements upfront with the molder, as they can recommend strategies like sequential valve gating or specific tooling finishes to optimize the as-molded appearance, or guide you on suitable post-processing.
Consistent wall thickness is crucial. Rapid changes in wall section can lead to inconsistent cellular core density, warpage, and pronounced sink marks as the part cools unevenly. Effective design for manufacturability (DFM) is key, focusing on gradual transitions, appropriate rib-to-wall thickness ratios, and careful gate placement to ensure uniform material flow and cooling. Mold flow analysis is essential to predict and mitigate these issues.
Gas-assist molding is often preferred for parts requiring very thick sections, internal hollow channels, or an improved surface finish without the characteristic swirl marks of structural foam. It uses inert gas injected directly into the molten plastic to core out thick sections and pack out the part, reducing sink marks and material usage while often providing a smoother surface, making it ideal for handles, frames, or components requiring precise internal features.
Structural foam tooling operates at much lower pressures, allowing for the use of less expensive aluminum tools or even cast Kirksite in some cases, significantly reducing upfront tooling costs compared to hardened steel tools for high-pressure injection molding. However, structural foam tools are often larger to accommodate bigger parts, and require specialized hot runner systems for the low-pressure process. The trade-off is often longer cycle times and different surface finish expectations.
Knit lines occur where two flow fronts of molten plastic meet and re-meld. In structural foam, these can be more pronounced visually and can create areas of reduced structural integrity due to the presence of the foaming agent interfering with complete fusion. Proper gate placement, multi-gating with sequential valve gating, and optimizing melt temperature and injection speed are critical DFM strategies to move knit lines to non-critical areas or minimize their impact on part strength.
Key material properties include melt flow index (to ensure good flow at low pressures), impact strength, flexural modulus for stiffness, and often flame retardancy (e.g., UL 94 ratings) for electrical enclosures. UV resistance is vital for outdoor applications. The choice of resin, typically commodity or engineering thermoplastics like PP, PE, ABS, or PC, must balance structural requirements with processability and cost, always considering the interaction with the blowing agent.