Hartford, CT
1. Marlee-Texen
Address: Hartford, CT (multiple Connecticut locations)
Phone: (860) 291-2598
Website: https://www.marlee-texen.com/
Founded: 1970s (50+ years in operation)
Services:
High-volume injection molding, short-run molding, custom plastic parts, design and manufacturing, custom automation, complex work cells
Industries Served:
Healthcare, luxury and beauty, consumer goods, packaging, automotive
Highlight:
Industry leader with over 50 years of innovative quality manufacturing in Hartford. Marlee-Texen specializes in high-volume production using advanced technologies and custom automation while also offering specialized short-run molding for smaller-scale needs. Their complex work cells and innovative design processes deliver reduced costs, greater efficiency, and improved product consistency. The company emphasizes sustainable plastic molding practices and serves multiple markets including healthcare, luxury goods, and automotive sectors.
2. MPS Plastics, Inc.
Located in Marlborough, CT (approximately 15 miles from Hartford)
Address: 10 Jones Hollow Road, Marlborough, CT 06447
Phone: (860) 295-9563
Website: https://www.mpsplastics.com/
Email: rich@mpsplastics.com
Founded: 1980s (40+ years in operation)
Facility: 25,000 square feet (with 5,000 sq ft expansion in 2005)
Services:
Custom injection molding, injection mold design and manufacturing, insert molding, tool and mold making, finishing, product design, plastics engineering, CAD/CAM services
Industries Served:
Automotive, biomedical, telecommunications, consumer products
Highlight:
New England’s premier custom injection molder with over 40 years of experience, uniquely positioned in Connecticut’s mold-making tradition. MPS Plastics manufactures all molds and auxiliary tooling in-house, providing direct access to toolmakers and engineers for rapid design changes. Their fully equipped Tooling Center includes CNC milling and EDM machines for precision and flexibility. Equipment ranges from 28 to 550 tons handling shot sizes from 0.10 to 84 ounces. The company operates 24/7 and offers limited-life molds and soft molds for cost-effective prototyping and short runs.
3. Ensinger Precision Components
Located in Putnam, CT (approximately 45 miles from Hartford)
Address: 365 Meadow Street, Putnam, CT 06260
Phone: (860) 928-7791
Website: https://www.ensinger-pc.com/
Facility: 19 injection mold presses
Services:
Injection molding, post-molding services (ultrasonic welding, heat staking, component assembly, packaging), CNC machining, engineering support
Industries Served:
Medical, aerospace, defense, industrial, electronics
Highlight:
Division of Ensinger Industries, a global supplier of high-performance polymers offering fabrication solutions throughout the U.S. and worldwide since 1934. The Putnam facility operates 19 injection mold presses with advanced automation, providing tight timelines for customers throughout Connecticut. Ensinger specializes in engineering and high-performance thermoplastic components and stock shapes. Their comprehensive post-molding services include ultrasonic welding, heat staking, and complete component assembly, enabling turnkey production capabilities.
New Haven, CT
1. EDCO Industries
Address: 300 Barnum Avenue, Bridgeport, CT 06608
Phone: (203) 333-8982
Website: https://www.edcoindustries.com/
Founded: 1980s (40+ years in operation)
Services:
Precision injection molding, hot stamping, ultrasonic welding, decorating, EMI coating, 3D printing, fastener application, assembly, design consultation, tooling development
Industries Served:
Medical, aerospace, defense, consumer products, electronics, industrial
Certifications: ISO 9001:2015, ITAR Registered
Highlight:
Family-owned business with over four decades of precision plastic injection molding expertise, led by second-generation plastics engineer John Szalan. EDCO combines ISO 9001:2015 certification with ITAR registration, qualifying them for defense and aerospace contracts requiring strict compliance. Their capabilities extend beyond molding to include hot stamping, ultrasonic welding, EMI coating, and 3D printing for prototyping. The company offers design consultation and tooling development to help customers bring ideas to life efficiently while meeting stringent industry standards.
2. Plastic Design International (PDI Molding)
Located in Middletown, CT (approximately 20 miles from New Haven)
Address: 50 Tuttle Place, Middletown, CT 06457
Phone: (860) 347-0451
Website: https://www.plasticdesign.com/
Founded: 1977
Services:
Injection molding, mold making, prototyping, short-run production, R&D support
Industries Served:
Medical, consumer products, industrial, electronics
Highlight:
Established in 1977 as a short-run prototype R&D specialist, PDI Molding has evolved over nearly 50 years into a complete injection molding resource center. Their expertise in prototype and R&D applications makes them an ideal partner for product development requiring quick iterations and design validation. PDI’s historical focus on short-run production continues to serve customers needing lower volumes without the expense of full production tooling.
3. Stelray Plastic Products, Inc.
Located in Ansonia, CT (approximately 15 miles from New Haven)
Address: 18 Pershing Drive, Ansonia, CT 06401
Phone: (203) 735-8774
Website: https://www.stelray.com/
Founded: 1957
Services:
Custom plastic injection molding, mold design and building, secondary operations, assembly
Industries Served:
Medical, consumer products, industrial, electronics
Highlight:
Family-owned custom injection molder operating since 1957 with over 65 years of manufacturing experience in Connecticut’s Naugatuck Valley. Stelray provides comprehensive services from mold design and building through production and assembly. Their longevity in the competitive Connecticut market demonstrates consistent quality and customer service. Located in Ansonia, they serve the greater New Haven area and southern Connecticut manufacturing community.
Notes
Connecticut’s plastic injection molding industry benefits from the state’s historical manufacturing heritage and proximity to major Northeast markets. The region around Hartford and New Haven features a mix of family-owned operations with multi-generational expertise and facilities backed by global corporations like Ensinger Industries.
Several Connecticut injection molders emphasize their in-house tooling capabilities, a legacy of the state’s traditional strength in precision manufacturing and tool making. MPS Plastics and Stelray both highlight complete mold design and fabrication services, enabling faster response times and tighter quality control compared to outsourced tooling.
The presence of ITAR-registered facilities like EDCO Industries reflects Connecticut’s defense and aerospace industry concentration, with numerous injection molders holding certifications required for military and government contracts. Medical device manufacturing also represents a significant market segment, with multiple companies maintaining ISO 13485 or FDA-compliant quality systems.
Companies are distributed throughout the state, from Putnam in the northeast (Ensinger) through the Hartford metro area (Marlee-Texen, MPS Plastics) to the New Haven and Bridgeport corridor along Long Island Sound, providing manufacturers with multiple sourcing options across Connecticut.
Research conducted January 2026. Verify all information directly with companies before business engagement.