Computer numerically controlled (CNC) programmers write computer programs that control the motion of machines and tools used to cut and shape precision products, such as machine and automobile parts. Related professional certifications are available through the National Institute of Metalworking Skills. To enter a certificate or associate's degree program, students must have a high school diploma or a GED. Some programs offer specialized training for a specific application, such as machining or press braking. Most individuals seeking a certificate in CNC programming already have basic knowledge of computers, electronics, and machine tools, and many have previously worked in machine shops. Students may have the opportunity to learn as an apprentice during their studies.