Sr Engineer I, Machining/Finishing

Company Overview: MP Materials (NYSE: MP) is rebuilding American industrial capability for a new era of autonomy, robotics, and electrification. We are the only U.S. company with a fully integrated rare earth supply chain—from mining and refining to advanced metal and magnet manufacturing. Our products include both the critical materials used to make permanent magnets and the finished magnets themselves—enabling next-generation technologies in robotics, automation, aerospace, transportation, defense, and energy systems. These materials are the foundation of physical AI—the convergence of computation, movement, and control. We hire ambitious, mission-driven people who want to tackle complex challenges and shape the future of strategic industries. Our culture is rooted in teamwork, resiliency, and integrity, with a deep commitment to operational excellence and national purpose. MP is rapidly evolving from a materials producer into a leading U.S. manufacturer—and our people are driving that transformation. Position Overview: MP Materials is seeking a hands-on Senior Engineer to lead the development and optimization of precision machining processes and dimensional control strategies for high-performance, rare earth permanent magnets. This role is critical to enabling manufacturability of complex magnet geometries with micron-level tolerances. The ideal candidate will bring deep expertise in geometric dimensioning and tolerancing (GD&T), statistical process control (SPC), and process capability analysis (E.g. Cpk, Ppk), along with hands-on experience machining brittle materials. Position Responsibilities: Lead the development and refinement of machining processes for cutting, grinding, shaping, and finishing of rare earth permanent magnets with tight dimensional tolerances and surface integrity. Apply advanced GD&T principles (ASME Y14.5) to interpret engineering drawings and ensure precise part geometry, flatness, squareness, concentricity, and perpendicularity. Review customer drawings and specifications, design and optimize DFM (Design for Manufacturability) of new magnet components, develop prototypes, modify existing parts, and improve machining processes. Conduct statistical analysis of machining data, including Cpk/Ppk, gauge R&R, and SPC charts, to monitor and improve process capability. Oversee installation, operation, troubleshooting, maintenance, and repair activities to ensure that pilot manufacturing equipment are installed and operate in accordance with specifications. Design and fabricate custom fixtures, jigs, and tooling to safely and accurately machine brittle, magnetized or demagnetized materials. Lead root cause analysis of dimensional defects and machining errors; develop corrective actions and continuous improvement plans. Implement process improvements to increase throughput, reduce scrap, and enhance dimensional control. Perform hands-on prototyping and process trials, working directly with in-house equipment and technicians. Mentor and manage engineers and technicians to ensure high-quality execution of experimental trials and data collection, and provide technical guidance in GD&T interpretation, statistical analysis, and machining best practices. Work closely with EHS to ensure that all work is done to ensure world-class health and safety, and full compliance with relevant environmental regulations. Other duties as assigned. Basic Qualifications: Bachelor’s degree in Mechanical Engineering, Manufacturing Engineering, or a related field. 5+ years of hands-on experience in precision machining and dimensional control, preferably involving brittle materials. Advanced proficiency in GD&T (ASME Y14.5 standard), blueprint reading, tolerance stack-up analysis, and DFM (Design for Manufacturability). Proven experience with statistical analysis tools (e.g. R, Minitab) and process capability metrics (Cpk, Ppk). Experience designing and optimizing fixtures and tooling for complex geometr…

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