About us:
Sigma Services LLC, founded in 2023, is a disabled veteran-owned business. We are comprised of professionals with extensive expertise in the manufacturing industry. Drawing from backgrounds in quality engineering, policy compliance, project management, and international business operations, we excel in delivering exceptional quality assurance services to manufacturers across multiple manufacturing sectors.
Jeff Kunz
Jeff Kunz is an accomplished project manager with extensive experience in supplier quality and manufacturing operations, particularly within BMW’s global production network. He successfully led quality engineering teams, ensuring supplier components met BMW Group’s rigorous quality standards while overseeing corrective actions and driving continuous process improvements. His work included managing advanced product quality planning (APQP), conducting supplier audits, and monitoring performance to ensure sustainable quality and production efficiency. Jeff consistently demonstrated his ability to manage cross-functional teams, collaborate with global suppliers, and navigate high-stakes escalation processes — making him a key player in maintaining operational excellence and supporting new model launches.
Before his time at BMW, Jeff served as a Quality Engineer at Lockheed Martin, where he supported a joint alliance with United Launch Alliance (ULA) on the Atlas V project — contributing to the quality assurance of one of the most reliable launch vehicles in history. His role involved ensuring compliance with rigorous aerospace standards, overseeing critical quality processes, and driving supplier performance to meet mission-critical objectives.
In addition to his corporate achievements, Jeff is a U.S. Army veteran who served in combat with the 101st Airborne Division in Iraq, where he developed exceptional leadership, adaptability, and problem-solving skills under high-pressure conditions — qualities that continue to drive his success in the professional world.
Owner
Andrey Ryzhkov
Andrey Ryzhkov is a results-driven Quality Management expert with extensive experience in automotive manufacturing, particularly within BMW’s North American operations. His career spans roles from Supplier Quality Assurance Specialist to leading an 18-member engineering team, overseeing quality, compliance, and process improvements for BMW’s X3 and X4 production. Andrey excels in problem-solving, change management, and culture development — blending technical expertise with leadership and coaching abilities. His background in Mechatronics supports his hands-on approach to quality control and operational efficiency. Beyond work, he demonstrates a strong commitment to community service, holding leadership roles in counseling, church coordination, and serving on a charter school board, reflecting his dedication to fostering growth and development both professionally and personally.
Co-Owner & COO
Rehling Kunz
Rehling is an accomplished professional that brings multiple years of experience in the manufacturing industry, specializing in policy compliance, project management, and international business operations. With a keen aptitude for analytical thinking, conflict resolution, and cross-cultural communication in both German and English, she excels in enforcing industry-specific regulations, negotiating international contracts, and managing multiple projects across different locations. Her expertise spans roles such as VP of Sales and Business Development, HR/Benefits Sales Specialist, and Owner of Rehling De Roos, LLC, where she demonstrated adaptability to international markets and proficiency in business management. With a key competency in policy development, project management, analytical skills, and customer orientation, she brings a wealth of knowledge and experience to Sigma Services as CEO.
CEO
Duong Nguyen
Duong Nguyen is a versatile and forward-thinking IT professional with extensive experience in software development, automation, and cloud technologies. With a strong foundation in computer science and a diverse technical skill set spanning programming languages, databases, AI, and web development, Duong has contributed to innovative projects at BMW Manufacturing Co., enhancing HR and logistics operations through custom-built applications and automation solutions. His international background, multilingual abilities, and education from both U.S. and Vietnamese institutions equip him with a unique global perspective, making him an adaptable and resourceful leader in driving digital transformation and operational efficiency.
Director of IT
Frans de Roos
Frans is an International Manager that brings a wealth of expertise developed through decades of diverse roles in general management, business development, and international sales across multiple industries and global locations. His background spans leadership positions in Europe and the USA, he possess a proven ability to drive significant sales growth, expand distributor networks, and implement effective marketing strategies. Proficient in multiple languages and equipped with a diverse skill set encompassing sales, marketing, administration, and finance, he offers valuable insights and strategic acumen honed through many years of extensive experience.
Project Manager