About the role#
Flex is looking for an Injection Molding Engineering Co-Op to join our team in Libertyville, Illinois. This part-time role supports our Process and Automation Engineering group. You will work alongside engineers to assist with injection molding process development and validation for high-precision medical components. This position requires working on-site for approximately 20 hours per week.
What you'll do#
- Assist with injection mold trials and process window development.
- Support startup optimization and parameter validation.
- Perform short-shot and imbalance studies.
- Conduct defect analysis and root cause investigations.
- Assist with IQ, OQ, and PQ documentation.
- Support tooling preventative maintenance and mold performance assessments.
- Attend team meetings to coordinate project work.
What you'll need#
- Current enrollment in an accredited university pursuing a degree in Plastics Engineering, Polymer Engineering, Mechanical Engineering, or Materials Science.
- A minimum 3.0 GPA.
- Understanding of injection molding fundamentals and mold tooling components.
- Basic knowledge of process validation in highly regulated environments.
- Experience with defect and root cause analysis.
- Ability to read basic mechanical drawings.
- Strong documentation and communication skills.
- Previous manufacturing floor internship experience is a plus.
Location & details#
- Location: Libertyville, Illinois.
- Work Modality: On-site.
- Term: Rolling.
- Compensation: Paid position, $27.50 to $44.50 per hour.
- Sponsorship: Not available.
About Flex
Flex is a manufacturing partner that provides design, build, and logistics services for various brands. The company operates across sectors including medical, automotive, and consumer digital electronics. It maintains a global presence with headquarters in Austin, Texas. The firm employs over 56,000 people and functions as a public company.
How to get in at Flex
Securing an internship at Flex requires speed because high-volume manufacturing firms often receive a large number of applications. Intern Insider sends an instant alert the moment a role matching your target is published, so you apply among the first. Early applicants get seen before the pile grows, which helps you stand out in a crowded field. You can also use Intern Insider to surface the recruiters behind these roles. Reaching out directly to ask about the position or a referral materially improves response rates compared to waiting in a queue.


