# Definition of Interpolation And Its Types In CNC

In This article, We discussed the Definition of Interpolation And Its Types In CNC, Which are Linear, Circular and Parabolic Interpolation

## Definition of Interpolation In CNC

Interpolation is the method by which contouring machines move from one location to the next. It is the feature of a contouring machine that merges the individual axis command into a pre defined tool path.

## Types of Interpolation In CNC

We have different types of Interpolation which are as follow:

### 1. Linear Interpolation In CNC

Moving the tool from one location to another in a straight line is linear interpolation. With this method of programming, any straight line can be machined.

This includes all taper cuts. A threc-axis milling machine is one that can move the tool with respect to the workpiece in three planes.

The tool can be moved left or right, up or down and in or out.

The milling machine has the capability of moving in a straight line from any location to any new location.

Many times, this movement requires that each of the three-axis movements be merged so that the tool moves in a straight line to the next location.

When programming linear moves,the coordinates must be given for the beginning and end of each line. Actually, the end of one line is beginning of the next.

Therefore,only the end of each line must he programmed. Linear interpolation is well applied to straight line moves, but many machined surfaces are not along a straight line.

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### 2. Circular Interpolation In CNC

The programming of arcs and circles was greatly simplified by the development of circular interpolation.

The information needed to be programmed to generate up to a 90° arc is the end pointof the are and the are radius.

If the same arc were programmed in linear interpolation with the same resulting accuracy, hundreds or even thousands of segments or cordinates must be calculated and programmed.

The NC control in circular interpolation takes the arc end point and its radius,and breaks the arc into small linear moves.

The resolution of the arc with this method is typically 0.005mm. To program a complete circle, the radius and four or five coordinates would need to be programmed.

Circular interpolation is limited toone plane at a time. Using circular interpolation, many second and third degree curves and free form shapes can be closely approximated in a series of arcs.

### 3. Parabolic Interpolation In CNC

Yet another method of interpolation, parabolic is especially suited to free form designs such as mold work and automotive die sculpruring.

Parabolic Interpolation positions the machine between three non straight line.