Numerical Control

6 Numerical Control

CONTENTS

Computer Numerical Control

·        Features of CNC

·        The Machine Control Unit for CNC

·        CNC Software

DNC

·        Direct Numerical Control

·        Distributed Numerical Control

Applications of NC

·        Machine Tool Applications

·        Other NCApplications

·        Advantages and Disadvantages of NC

NC Part Programming

·        NC Coding System

·        Manual Part Programming

·        Computer Assisted Part Programming

·        Part Programming with APT

·        NC Part Programming Using CAD/CAM

·        Manual Data Input

Engineering Analysis of NC Positioning Systems

·        Open Loop Positioning Systems

·        Closed Loop Positioning Systems

·        Precision in NC Positioning

Numerical control (:\C) is a form of programmable automation in which the mechanical actions of a machine tool or other equipment are controlled by a program containing coded alphanumeric data.The alphanumerical data represent relative positions between a workhead and II workpar t as well as other instructions needed to operate the machine, The workhead i, a cutting tool or other processing apparatus, and the workpart is the object being proces~ed, Whcn thc current job is ""mpleted. the program of instructions can be changed to process a new job. lhc capability to change the program makes NC suitable for low and medium production. It is much easier to write new programs than to make major alterations of the processing equipment.

Numerical control can be applied to a wide variety of processes. The applications divide into two categories; (Il machine tool applications, such as drilling, milling, turning, and other metal working; and (2) non machine tool applications.such as assernhly.drafting, and inspection. The common operating feature of NC in all of these applications is control of the workhead movement relative to the work part.