Numerical control change into computer numerical control

Numerical control (NC) refers to the automation of machine tools that are operated by abstractly programmed commands encoded on a storage medium, as opposed to manually controlled via handwheels or levers, or mechanically automated via cams alone. The first NC machines were built in the 1940s and 1950s, based on existing tools that were modified with motors that moved the controls to follow points fed into the system on punched tape. These early servomechanisms were rapidly augmented with analog and digital computers, creating the modern computer numerical control (CNC) machine tools that have revolutionized the machining processes.

In modern CNC systems, end-to-end component design is highly automated using computer-aided design (CAD) and computer-aided manufacturing (CAM) programs. The programs produce a computer file that is interpreted to extract the commands needed to operate a particular machine via a postprocessor, and then loaded into the CNC machines for production. Since any particular component might require the use of a number of different tools-drills, saws, etc., modern machines often combine multiple tools into a single “cell”. In other cases, a number of different machines are used with an external controller and human or robotic operators that move the component from machine to machine.

Although modern data storage techniques have moved on from punch tape in almost every other role, tapes are still relatively common in CNC systems. Several reasons explain this. One is easy backward compatibility of existing programs. Another is the principle, mentioned earlier, that individual firms tend to stick with whatever is profitable, and their time and money for trying out alternatives is limited. A small firm that has found a profitable niche may keep older equipment in service for years

One change that was implemented fairly widely was the switch from paper to mylar tapes, which are much more mechanically robust. Floppy disks, USB flash drives and local area networking have replaced the tapes to some degree, especially in larger environments that are highly integrated.

Since about 2006, the idea has been suggested and pursued to foster the convergence with CNC and DNC of several trends elsewhere in the world of information technology that have not yet much affected CNC and DNC. One of these trends is the combination of greater data collection (more sensors), greater and more automated data exchange and data mining to yield a new level of business intelligence and workflow automation in manufacturing. Another of these trends is the emergence of widely published APIs together with the aforementioned open data standards to encourage an ecosystem of user-generated apps and mashups, which can be both open and commercial—in other words, taking the new IT culture of app marketplaces that began in web development and smartphone app development and spreading it to CNC, DNC, and the other factory automation systems that are networked with the CNC/DNC. MTConnect is a leading effort to bring these ideas into successful implementation.