Full-Service High Precision Production Machining

Headquartered in Central Indiana, GMI Corporation is an ISO 13485 certified, FDA registered (3011743372) full-service high precision production machining contract manufacturer.

Our 69,000 sq. ft. facility was designed and built to meet the highest standards for Good Manufacturing Practice (GMP). We have over 40 Swiss turn style lathes and Mazak multi-axis lathes (with tolerance capabilities down to plus or minus two ten thousandths of an inch (+/- .0002″) or +/-.00508mm), a suite of machines for degreasing and tumbling, dedicated assembly, kitting and labeling areas, a controlled environment room, and a fully capable quality and metrology lab.

Our History

31 years ago, it all started with one man, a single machine, and a passion for quality parts.


Our founder, Fred McWilliams, began his entrepreneurial journey in 1990 with a wealth of personal skill and a love for high precision. His start-up was called Greenwood Machine, Inc.

Word of mouth quickly spread of Fred’s expertise and in a relatively small timeframe the business grew into an industry leader, providing precision RF connector and medical device components and assemblies.


In 2013, the company streamlined and rebranded as GMI Corporation, while expanding its assembly and kitting services.


In 2020, Fred retired and GMI formally transitioned to a 100% employee-owned company (ESOP) with a focus on high precision machining, assembly, and value-added services for demanding markets, including medical device, RF connectors, medical gas, aerospace and defense.

His legacy of precision, collaboration, quality, environmental sustainability, process control and strong relationships continue to live on in all that we do at GMI.

We Strongly Believe in…
Growing Successful Relationships

As an employee-owned manufacturer focused on high precision machining, assembly and value-added services for demanding markets, we build relationships with:

  • Our customers by providing the highest level of quality and on-time delivery performance
  • Our employees by providing a great place to work where everyone can thrive and develop
  • Our community by giving back to the world through charitable activities and being environmentally conscious

These principles shape the way we do business and how we treat our clients and employees:

  • Honest & Ethical – Do the right thing; do things right
  • Quality is not just a word, it’s the way we do business
  • Know your priorities
  • Do what you said you were going to do
  • We win / lose as a team

GMI strives to promote and respect all human rights in accordance with federal and international laws with our employees, suppliers, and customers.

How Can We Help You Today?

Corporate Headquarters & Manufacturing Operations

700 International Drive
Franklin, IN 46131

Phone: (317) 736-5116
Fax: (317) 736-5125
Email: info@gmicorp.com