Principal Engineer

Job Posting Start Date 09-04-2025 Job Posting End Date 09-10-2025

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

JETCOOL Technologies a Flex company is a fast-moving cooling solution provider, and successful MIT-spinoff, producing game-changing cooling solutions for aerospace, electric vehicles, and data centers. We are looking for a Principal Engineer based in Littleton, Ma.

What a typical day looks like:

• Work with JetCool commercial team to adapt customer requirements into an implementation ready design.
• Advance technology maturity of new secondary system design elements (water quality, flow regulation etc.).
• Work with manufacturing partners to establish modular design specifications for fast customer implementation and deployment.
• Lead communication and technical exchange with customers, build and cultivate customer and partner relationships, focusing on behind and beyond the rack cooling infrastructure
• Work with Flex supply chain to enable vendors and ensure specifications are up to date.
• Lead technical problem solving and pull in cross functional team to provide innovative thermal cooling system solutions

The experience we're looking to add to the team:

• Bachelor (or higher) of Science (B.S. in mechanical or aerospace engineering) and 5+ years of work experience and 2+ years thermal heat rejection architecture / infrastructure experience
• Excellent first principles knowledge in mechanical engineering, fluid dynamics, thermodynamics, and system heat transfer
• Track record of delivering thermal heat rejection solutions to customers with high quality and on schedule
• Strong communication skills
• Strong problem-solving and thermal / fluid system analysis skills
• Ability to specify smart heat rejection system architectures

What you'll receive for the great work you provide:

• Full range of medical, dental, and vision plans
• Life Insurance
• Short-term and Long-term Disability
• Matching 401(k) Contributions
• Vacation and Paid Sick Time
• Tuition Reimbursement

Pay Range (Applicable to Massachusetts)

$147,700.00 USD - $203,100.00 USD Annual

Job Category
Production Engineering

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).

Client-provided location(s): Boxborough, MA

Job ID: Flex-WD207647

Employment Type: FULL_TIME

Posted: 2025-09-05T20:03:59