Top 21 Injection Molding Manufacturers in Michigan 2026

21st Century Plastics Corp.

Potterville, Michigan

21st Century Plastics Corporation operates from Potterville, Michigan, where it was founded in 1997. The business transitioned to 100% employee ownership in 2010 under an Employee Stock Ownership Plan.

Agapé Plastics, Inc.

Walker, Michigan230 employees

Agapé Plastics, Inc. is headquartered in Walker, Michigan.

Grand Traverse Plastics Corp (GTP)

Williamsburg, Michigan

Grand Traverse Plastics Corp (GTP) has operated from Williamsburg, Michigan, in Grand Traverse County since its founding in 1981. The company is a U.S.-based manufacturer of custom plastic injection molded components.

Ironwood Plastics Inc.

Ironwood, Michigan

Ironwood Plastics Inc. was founded in 1979 by Gordon K.

Jimdi Plastics Inc

Allendale, Michigan60 employees

The privately owned company began by producing a proprietary flooring system for the agricultural industry before expanding into custom injection molding for other customers. The company operates a 40,000-square-foot facility in Allendale housing 16 injection molding presses ranging from 110 to 1,100 tons, supported by a staff of 60.

KAM Plastics Corp

Holland, Michigan

KAM Plastics Corp was founded in 1994 in Holland, Michigan, by Paul Kalkman and Cleon Morgan. The company specializes in plastic injection molding and assembly, operating over 50 molding machines across facilities in Holland, Michigan, and Arteaga, Mexico (via the KAMEX joint venture).

PTI Engineered Plastics

Macomb, Michigan

PTI Engineered Plastics operates from a 160,000-square-foot facility in Macomb, Michigan. The privately held company was founded in 1984 as Proto-Tech Industries, producing functional prototype molds and injection-molded samples before adopting its current name in 1987 to reflect a turnkey, mind-to-manufacturing model.

Summit Plastic Molding

Shelby Township, Michigan

Summit Plastic Molding was founded in 1982 in Shelby Township, Michigan, initially operating as a tool shop. The company later expanded into a full-service injection molding supplier, adding manufacturing capabilities alongside its tooling expertise.

West Michigan Plastics

Holland, Michigan

West Michigan Plastics, Inc. was founded in 1986 and incorporated in 1991 in Holland, Michigan.

Asahi Kasei Plastics North America

Fowlerville, Michigan

Asahi Kasei Plastics North America operates from Fowlerville, Michigan, as the North American arm of Japan’s Asahi Kasei Corporation. The subsidiary was established to bring the parent company’s portfolio of engineering plastics and technical services to the U.S.