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PTI Celebrates 40 years in business!

For four decades, PTI Engineered Plastics has been on a remarkable journey – a story not just of growth, but of transforming ideas into life-changing products. We began in 1984 as a humble dream in a garage size space, crafting prototypes for all industry. Today, we’re a team (Team PTI, as we proudly call ourselves) that boasts an impressive roster of 30 of the world’s leading medical device manufacturers as clients.

This incredible achievement isn’t magic – it’s the result of a passionate team who are more than just employees. They’re inventors, troubleshooters, and collaborators, all fueled by a shared desire to make a difference. It’s no wonder we’ve been recognized as the 2023 Plastics News Processor of The Year – a testament to the collective brilliance of Team PTI.

We are honored and humbled to be amongst the esteemed recipients of this prestigious award.


Today’s PTI Engineered Plastics was originally formed by Mark Rathbone in 1984 as Proto-Tech Industries, which produced functional prototype molds and injection molded samples, serving primarily the automotive industry. Proto-Tech was located in Mark’s hometown of Macomb, Mich., where PTI has been located for 40 years. In 1987, the company changed its name to PTI Engineered Plastics to reflect the mind-to-manufacturing operations PTI continues to offer today. To expand the company’s design capabilities, PTI Design was launched in 2010 with an in-house design studio specializing in product innovation and development.

Over the years, PTI has created a full-service, one-stop-shop housing all manufacturing processes needed to design and create complex plastic components used in advanced medical devices and many other innovative products through various industries. This way, it retains control over the entire manufacturing process, as well as the product quality stream, and simplifies the entire process for its customers.

From the beginning, PTI has always sought ways to improve upon and expand its services to customers to ensure they have an exceptional experience, from concept to completion, and to support its team members along the customer’s journey.


Always customer-driven and future-focused, PTI embraces new manufacturing technologies to offer its customers the most up-to-date tools to ensure superior manufacturing processes and high-quality products. PTI has continued to invest in new technology over time. Recently, PTI replaced nearly all of its injection molding presses with modern electric presses engineered for faster, repeatable, more precise, and energy-efficient production and to align with Industry 4.0. PTI also expanded its Class 8 cleanroom footprint by 8,000 sq. ft. in its existing facility to continue to grow its medical device business and other industries and customers requiring cleanroom molding and assembly.


The team at PTI works with customers from design through manufacturing. PTI’s design engineers engage with customers at the start of a project and support them through the Design for Manufacturing (DFM) phase to ensure each new product has the “trademark” characteristics of the customer’s family of products, and that the product is best designed for manufacturability, as well as functionality in the field. Team PTI works with each customer on Design for Manufacturability and part tolerances to ensure quality production parts. Drawing on its vast depth of knowledge, Team PTI builds the right tool to produce the part repeatedly without variation and with consistent high quality.


PTI’s employees come in each day knowing they have the power to make a difference by contributing to the design, development and production of products that help change people’s lives for the better. The PTI culture fosters a climate of curiosity and problem-solving — two powerful motivational elements for employees that are not often found at other manufacturers. In fact, by employee vote, PTI earned the Detroit News Top Workplace Award seven times in the past nine years.

As PTI looks to the future, it’s clear that the strong foundation of dedication, loyal employees, its focus on adopting new technologies and satisfied long-term customers will continue to be the bedrock upon which PTI will build its future success.


Mark Rathbone leases a 1500 square foot building near the corner of 8 mile and Mound on the border of Detroit and its suburbs…and not known for being the safest place in the state. After many weeks of clean up and some fresh paint, Mark soon realized he had the best-looking property on 8 Mile. Mark purchased 2 Bridgeport machines, a cutter grinder and a surface grinder. PTI was born.

PTI produces the first prototype part for its first customer.

PTI expands by moving into a new building in Clinton Twp, MI

PTI changes its name from Proto-Tech Industries to PTI Engineered Plastics to more accurately reflect the the Mind-to-Manufacturing™ operations.

PTI moves into yet another new building in Clinton Twp, MI

PTI expands its Clinton Twp operations with a new facility of over 30,000 sq ft.

PTI adobpts RJG scientific molding

PTI adds a Customer Suite for customer collaboration

PTI’s growth dictates an expansion to a second facility in Shelby Twp (50,000 sq ft).

PTI begins to invest heavily in new technology, like Pad printing and Centralized Drying & Conveying systems

PTI begins to phase out older hydraulic presses with more energy efficient electric presses.

PTI expands to an astonishing 115,000 sq ft building that it currently occupies today.

PTI adds Cleanroom manufacturing to support an increase in medical device injection molding

PTI expands its building an additional 45,000 sq ft for a total of 160,000 sq ft of manufacturing space.

PTI expands its metrology and quality engineering labs

During the height of the pandemic, PTI manufactured ventilator components as well as designed, built tooling, manufactured and donated over 150,000 face shields for first responders, hospitals and food kitchens in the local community.

PTI expands its Class 8 cleanroom operations to over 8,000 sq ft of manufacturing space.