How Do CNC Machines Work?

How Do CNC Machines Work?

CNC Basics

CNC stands for Computer Numerical Control. It refers to the use of computers to control the movement of the axes of the machine. It could be a cnc milling machine, cnc router, cnc lathe, cnc engraving machine, cnc laser, wire cut EDM, cnc plasma cutting machine, cnc waterjet or vertical machining center. The machine could have 2, 3, 4, 5 or more axes. The CNC machine has its own controller which drives the motors and the spindle.

The procedure to make every job more or less remains the same on a CNC machine, regardless of the industry, be it a sparking electrode, a punch die, shoe sole die or a name plate, signs, signage.

The process can be summarized in three simple steps:

1. Acquiring the CAD data

In most of the cases, a 2D drawing created in any CAD software like AutoCAD, CAXA, Corel Draw acts as a CAD source. Sometimes, a 3D model created in software like Pro-Engineer, SOLIDWORKS, IDEAS is used as source.

2. Generating the toolpath

The CAD image is taken to the CAM software and the required tool path is made using the appropriate tools. It is very important to use the proper tool and proper feed rates to get a good output. It is essential to take into account what material is being used, what is its hardness and then decide on the proper tool.

Before generating the tool path ensure that the appropriate machine was selected. Every CAM software comes with various drivers for different machines. This generates the tool path in just the way the machine can interpret, some use G code, some use 3B code etc. If the appropriate machine is not selected the tool path generated will be useless for your machine.

3. Sending the toolpath 

Sending the tool path is as simple as sending a file to a printer. The only difference is that interface software like Cimco has to be used to send the file to the machine. Some machine use DSP control system, so send file via USB. Some machine by PCI control card computer control, so just load the file into the control card is ok. Some machine use Syntec, LNC, FANUC, MITSUBISHI, SIEMMENS, FAGOR control system, file can be send via LAN or CF card.