Computer Numerical Control is a process by which a machine tool is controlled through a program of alphanumeric data. A set of parameters input into the program control the motion of a tool for such functions as the depth of cut, feed, speed, spindle and coolant control. A computer is customized with special hardware and software, and special algorithms guide a tool through the special functions and features. CNC machining is applied to the manufacture plastic and metal components.
Systems Set Up
A computer aided design CAD drawing is rendered in 2D or 3D, and programming entered into a CNC device. Once the programming is completed and loaded, an operator performs ‘cutting air’ that is a test run without a product to check for errors. This step ensures precision operation without damage to a product or the machine. Almost any machine tool can be controlled with CNC production machining from lathes to lasers.
* Parts Programming
* Machine Controls
* Variety of Machine Tools
Precision and CNC
In CNC production machining, there are three critical measures to precision, resolution, accuracy and repeatability. Resolution is the distance separating two points. Accuracy depends on resolution and machine inaccuracy. Repeatability is the system’s ability to return to a point programmed within the system, and it is defined by a machine’s inaccuracies. Inaccuracies are caused by chatter, deflection or thermal deforms to name a few. Thermal deformations tend to cause significant inaccuracies. Inaccuracies are measured in the basic unit length (BLU).
* Resolution
* Accuracy
* Repeatability
Benefits of CNC Precision
cnc production machining allows the complex, precise and exact repeated machining of three-dimensional shapes that is impossible to produce with manual machining. With CNC, production times are shorter than manual machining. Greater flexibility than manual methods is possible with CNC machining, and contour machining is made possible. Human error is reduced, and waste eliminated helping to keep costs low.
* High Accuracy
* Speed
* Simpler Fixture
CNC is expensive to install, but once installed the increased speed of production, elimination of wasted material, precision, accuracy and complexity of the finished product justify the initial expense. CNC guided tools in the hands of a skilled operator and programmer made the manual shop obsolete.
