Lets start with a brief introduction. CNC stands for Computer Numerical Control and it has been around since the early 1970s. Before it was christened CNC, it was called NC, for Numerical Control. When computers were introduced during 1070s, the name changed. It has stroked almost all manufacturing forms in almost all stages of production. CNC machines either substitute some existing manufacturing processes or combine work with them.
A CNC program is just any other set of instructions. Its written like a sentence and the order of operation is chronological. The machine will then execute that set of instructions step-by-step. A special series of CNC words/codes are used to relay what the machine is supposed to do. CNC codes begin with letter addresses (like S for spindle speed, and X, Y & Z for common linear axis motions).
When certain codes are arranged together in a coherent method, this group of CNC codes create a command that is like a sentence. A common CNC machine will only be needing around 40-50 words/codes to program different commands. See, its not very difficult to learn.
Although CNC sounds very independent and do-it-all, there are a few words that you need to know to fully understand CNC operations.
CAM stands for Computer Aided Manufacturing. It simplifies the programming processes which are new, and added to the CNC program regularly. Of course, the easy applications can be programmed with only the simplest machines around: the pen, paper and calculator. However, more complex programs are vital regularly. It is when composing these programs become much more tricky and (worse) tedious.
The CAM is a program that runs on a computer that aids the CNC programmer with the programming. It also works hand-in-hand with the CAD (Computer Aided Design) design drawing (those designs engineers compose/nurture). With the CAM helping, redefinition of the work-piece configuration is not needed. What the CNC programmer is left to do is just to specify the machine operations to be executed and the CAM system will compose the CNC program automatically. Thanks to CAM, programming tediousness will not be a problem to the CNC programmer again.
THE DNC SYSTEM
DNC stands for Distributive Numerical Control. It is a computer that is connected with one or more CNC machines, forming a network. When a program is manually composed and ready to be loaded to the CNC control, it is being typed right into the control. However, this is like using the CNC machine as a luxurious keyboard.
Moreover, if the CNC program is achieved with the help of CAM, it is already in text form and ready to be loaded to the CNC control. The DNC simply distributes the CNC program to more than one CNC machine. Lately, the newest controls are more advanced in terms of networking capabilities and can be networked with, say, the Ethernet.
If its your first time to read and learn about the CNC, it may sound so mighty and ubiquitous. Its about time you learn they also need help from some programming friends such as the CAM and the DNC. No man is an island; but hey, neither are CNC machines.