Plastic Molding Engineer Co-Op

Job Posting Start Date 04-01-2026 Job Posting End Date 04-05-2026

Flex is the diversified manufacturing partner of choice that helps market-leading brands design, build and deliver innovative products that improve the world.

A career at Flex offers the opportunity to make a difference and invest in your growth in a respectful, inclusive, and collaborative environment. If you are excited about a role but don't meet every bullet point, we encourage you to apply and join us to create the extraordinary.

Job Summary

To support our extraordinary teams who build great products and contribute to our growth, this Summer, we’re looking to add a Plastic Molding Engineer Co-Op located in our Libertyville, IL site.

Reporting to Process & Automation Engineering Team, the Intern will support injection molding process development and validation activities for high-precision medical components, while collaborating and working alongside Engineers and cross-functional teams.

What a typical day looks like:

• Assist in injection mold trials and process window development
• Support startup optimization and parameter validation
• Perform short-shot and imbalance studies
• Support defect analysis and root cause investigations
• Assist with IQ/OQ/PQ documentation
• Support tooling PM and mold performance assessments
• Attend team meetings to support project work as needed

Student qualities we’re seeking for this internship assignment:

• Currently enrolled student pursuing Bachelors degree in Plastics Engineering, Polymer Engineering, Mechanical Engineering, or Materials Science major
• Understanding of Injection Molding Process (injection molding fundamentals)
• Basic process validation knowledge in highly regulated environments
• Defect & root cause analysis experience
• Understanding of mold tooling components and ability to read basic mechanical drawings
• Strong documentation and communication skills
• Previous manufacturing floor internship experience a plus!

Co-Op Program Requirements:

• Ability to work 40 hours/week (in person) during the co-op assignment
• Currently enrolled in 4-year accredited university
• 3.0 GPA

Pay Range will be based on Student Guidelines: $28.50-$30.50 for undergrads

Pay Range (Applicable to Illinois)

$16.74 USD - $23.02 USD Hourly

Job Category

Intern

Relocation: Not eligible

Is Sponsorship Available?

No

Flex is an Equal Opportunity Employer and employment selection decisions are based on merit, qualifications, and abilities. We do not discriminate based on: age, race, religion, color, sex, national origin, marital status, sexual orientation, gender identity, veteran status, disability, pregnancy status, or any other status protected by law. We're happy to provide reasonable accommodations to those with a disability for assistance in the application process. Please email accessibility@flex.com and we'll discuss your specific situation and next steps (NOTE: this email does not accept or consider resumes or applications. This is only for disability assistance. To be considered for a position at Flex, you must complete the application process first).