Mechanical Engineering Associate Jobs in O Fallon, MO

Location: O'Fallon, Missouri

Business Unit: Defense Electronics Group

Reports To: Mechanical Engineering Manager (initially reporting to Graham; organizational reporting may evolve as the team grows)

The Defense Electronics Group is seeking both an Associate Mechanical Design Engineer and an experienced Mechanical Design Engineer to support the development of advanced defense electronics products and related mechanical systems. These positions will play a key role in the design, development, integration, testing, and production support of ruggedized electronic assemblies, packaging solutions, power systems, and electromechanical products used in demanding military and defense applications.

Successful candidates will bring experience in mechanical design for electronics, including areas such as electronic packaging, EMI/EMC considerations, military-grade connectors, thermal management, and mechanical power systems. Candidates should demonstrate strong technical ownership and accountability, with the ability to support products throughout the full engineering lifecycle from concept through production and sustainment.

• Design and develop mechanical components, assemblies, and packaging solutions for defense electronics products.
• Create and maintain detailed 3D models, drawings, specifications, and engineering documentation.
• Support electronic packaging designs with consideration for thermal performance, structural integrity, environmental requirements, and EMI/EMC requirements.
• Select and integrate military-grade and commercial connectors, fasteners, hardware, and electromechanical components.
• Collaborate closely with electrical, systems, manufacturing, quality, and supply chain teams throughout product development.
• Conduct design analyses, tolerance studies, and engineering trade-off evaluations.
• Support prototype builds, testing, qualification activities, and product validation efforts.
• Identify and resolve design issues during development, integration, and production.
• Drive continuous improvement initiatives related to product performance, manufacturability, reliability, and cost.
• Support transition of products from development into production and ongoing sustainment activities.
• Maintain compliance with applicable military, defense, customer, and regulatory requirements.

• Bachelor's degree in Mechanical Engineering or related engineering discipline.
• 0-5 years of mechanical design experience.
• Experience using 3D CAD tools for mechanical design and documentation.
• Understanding of mechanical engineering fundamentals, including materials, manufacturing processes, GD&T, and tolerance analysis.
• Exposure to electronic packaging, electromechanical systems, or machine design through industry experience, internships, co-ops, or academic projects.
• Strong communication and collaboration skills.
• Ability to obtain and maintain applicable security requirements as needed.

• Bachelor's degree in Mechanical Engineering or related engineering discipline.
• 7+ years of mechanical design and product development experience.
• Demonstrated experience designing ruggedized electronics packaging, defense electronics products, or related electromechanical systems.
• Strong knowledge of EMI/EMC design considerations, thermal management, and environmental design requirements.
• Experience with military or defense industry standards and practices.
• Proven ability to lead complex technical efforts and provide guidance to less experienced engineers.
• Ability to obtain and maintain applicable security requirements as needed.

• Experience in the aerospace, defense, military, or highly regulated electronics industries.
• Experience in electronic packaging, embedded systems hardware integration, or electromechanical product development.
• Familiarity with MIL-spec connectors and military environmental requirements.
• Experience with thermal analysis, FEA, vibration, shock, or environmental testing.
• Knowledge of DFM/DFA principles and manufacturing support.
• Experience supporting products through full lifecycle development, production, and sustainment.
• Project leadership or technical lead experience (Experienced level).

This is a Contract to Hire position based out of O'Fallon, Missouri.

The pay range for this position is $55.00 - $67.00/hr.

Individual compensation offered for this position within this range will depend on many factors, including qualifications, skills, relevant experience, job knowledge, geographic location, internal equity, and other pertinent job-related factors.

Eligibility requirements apply to some benefits and may depend on your job classification and length of employment. Benefits are subject to change and may be subject to specific elections, plan, or program terms. If eligible, the benefits available for this temporary role may include the following: • Medical, dental & vision • Critical Illness, Accident, and Hospital • 401(k) Retirement Plan – Pre-tax and Roth post-tax contributions available • Life Insurance (Voluntary Life & AD&D for the employee and dependents) • Short and long-term disability • Health Spending Account (HSA) • Transportation benefits • Employee Assistance Program • Time Off/Leave (PTO, Vacation or Sick Leave)

This is a fully onsite position in O'Fallon,Missouri.

This position is anticipated to close on Sep 11, 2026.

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