Mechanical Engineer Defense Freelance Jobs (NOW HIRING)

About the Company

Founded in 1981, Combined Systems, Inc. (CSI) is the recognized leader in the design, manufacture, and marketing of security products for global defense and law enforcement markets. CSI is the premier supplier of less-lethal munitions and launching systems, serving riot control, police tactical teams, corrections officers, and military units worldwide. Our blue-chip customer base includes the U.S. Army, U.S. Marine Corps, U.S. Navy, and a majority of U.S. law enforcement agencies, as well as foreign military and security forces.

Mechanical Engineer Summary

The Mechanical Engineer supports the design, development, testing, and production of less-lethal munitions, pyrotechnic devices, tactical launchers, and precision-engineered defense components. This role focuses on mechanical design, product reliability, manufacturing support, and continuous improvement within a high-mix, defense-grade production environment. Ideal candidates are analytical, detail-oriented, and motivated to solve complex engineering challenges while collaborating across multiple disciplines.

Why Choose Combined Systems, Inc. (CSI)?

• 3-Day Weekends: Work 10-hour shifts, Monday – Thursday. Fridays are for optional overtime.
• Work in Comfort: Clean, seated assembly in a fully climate-controlled facility.
• Double Your Vacation: Earn 40 hours of PTO starting Day 1 (usable on day 91), plus 8 extra hours every quarter for perfect attendance (up to 72 hours total!).
• Enjoy our enhanced attendance program featuring monthly $500 attendance awards, quarterly PTO incentives, and dedicated sick time that allows employees to care for their health without losing attendance rewards.
• Low-Cost Health: Standard medical is just $18/week (Buy-up HRA option available at $49/week). Add dental/vision to either.
• Retirement & Extras: 401(k) with a 3% match after 6 months, plus paid holidays.
• Stability: Global defense and U.S. Military supplier operating proudly since 1981.

What You Will Do & Who We Are Looking For

The Mechanical Engineer supports the design, development, testing, and production of less-lethal munitions, pyrotechnic devices, tactical launchers, and precision-engineered defense components. This role focuses on mechanical design, product reliability, manufacturing support, and continuous improvement within a high-mix, defense-grade production environment.

Key Responsibilities

• Mechanical Design — Create and refine 3D models, assemblies, and detailed drawings for munitions, launchers, and mechanical subsystems.
• Engineering Analysis — Perform stress, thermal, vibration, and tolerance analyses to ensure product performance and safety.
• Prototype Development — Build and evaluate prototypes; conduct iterative design improvements based on test data.
• Testing & Validation — Develop and execute test plans for ballistic, environmental, and functional evaluations.
• Manufacturing Support — Troubleshoot production issues, optimize manufacturability, and support tooling and fixture design.
• Documentation — Generate BOMs, specifications, ECNs, and technical reports in accordance with internal and defense-industry standards.
• Cross-Functional Collaboration — Work closely with R&D, chemistry, ballistics, quality, and production teams to support new product introduction and continuous improvement.
• Compliance & Safety — Ensure designs meet applicable NIJ, ATF, DoD, and internal safety requirements for energetic and pressure-bearing systems.
• Supplier Interaction — Evaluate vendor components, materials, and manufacturing capabilities.

Strict Employment Requirements

Because we manufacture high-quality defense and law enforcement security products, all hires must meet these federal and safety standards:

• Pass a pre-employment drug screening and continuous random drug testing.
• Pass a federal Bureau of Alcohol, Tobacco, Firearms (ATF) criminal background check.

Qualifications

• Bachelor's degree in Mechanical Engineering or a closely related field.
• Proficiency with CAD software (SolidWorks preferred).
• Strong understanding of mechanical design principles, GD&T, and manufacturing processes.
• Ability to perform engineering calculations and interpret test data.
• Experience working in a manufacturing or product-development environment.
• Strong communication, documentation, and problem-solving skills.
• Ability to work hands-on with prototypes, test equipment, and production tooling.

Preferred Experience but Not Required

• Experience with energetic materials, pyrotechnics, or pressure-bearing mechanical systems.
• Background in defense, aerospace, or munitions manufacturing.
• Familiarity with ballistic testing, environmental testing, or reliability engineering.
• Knowledge of Lean manufacturing, DFMA, or continuous-improvement methodologies.
• Experience designing tooling, fixtures, or test equipment.
• Exposure to regulatory compliance for defense-related products.