The Axes and Origin

                             

An effective way to picture the three Cartesian axes shown in Figure 1 is by learning the right-hand rule. Turn your right palm up, and then extend only the thumb and forefinger. This forms an "L," with the middle finger up to the ceiling, as in Figure  The thumb is the X-axis, the forefinger is the Y-axis, and the elevated center finger is the Z-axis.

                                      The point where all three axes meet is called the origin. This occurs roughly in the palm of your hand, or the corner of the box. The origin is important because it is the central reference point for all the dimensions. You can think of the origin as the "You are here!" dot on a map. Within the Cartesian system, any specific location can be described by its place along the three axes and the distance from the origin.

Read more »

Explain CNC Coordinates

Coordinate Metrology - Technology and Application

All the positions and motions of a computer numerical control (CNC) machine are understood in terms of numbers. Numbers describe the shape of the work piece, the movement of the cutting tool, the depth and speed of the cut, etc.

How exactly are numbers used in this way? The common system used to describe location is called the Cartesian coordinate system, which consists of a cubic grid of imaginary lines. The Cartesian system defines the location of a single point in three-dimensional space using three axes, which are shown in Figure 1. These axes are called the X-axis, Y-axis, and Z-axis, and each one indicate a particular direction.



An axis is an imaginary straight line. In the Cartesian system, the X-, Y-, and Z-axes meet at right angles. In other words, they join together like the corner of a box, as shown in Figure 2.

Read more »

CNC Coordinates

CNC Coordinates

The Cartesian coordinate system is the fundamental system used to describe the motion of the tool and workpiece within a three-dimensional space. CNC machines use numbers to locate a particular point along the X-, Y-, and Z-axes. They perform a series of instructions, one after another, to machine the workpiece and create incredibly accurate dimensions.

                             CNC machines use either incremental or absolute coordinates to move from one location to the next. With incremental coordinates, the current position acts as the origin for the next position. With absolute coordinates, the origin stays in a fixed location, and each new location is calculated from that fixed position. Most CNC machines can move along multiple axes at once to perform contour operations.

                             The axes on any CNC machine are determined by set standards. The Z-axis is always parallel to the machine spindle. On a machining center, the spindle holds the cutting tool. On a turning center, the spindle holds the rotating workpiece. Nowadays, CNC machines can create complex shapes such as circles, curves, and cones.

you want more about this click below link

CNC Coordinates

The Axes and Origin

Positive and Negative Directions

Coordinates in Blueprints

Incremental Coordinates

Rotational Axes

Absolute Coordinates

Contouring

Coordinate Standards for Machines

Standard Axes Locations

Coordinates for the Vertical Milling Machine

Coordinates for the Horizontal Milling Machine

Coordinates for the Turning Center

Machine Zero and Program Zero

Read more »

Rapid traverse G00

G00 Linear interpolation in rapid traverse

If G00 is selected, the rapid traverse speed of the axes specified in the machine parameters is used. Here, the resulting speed of the axes is given by the condition that at least one axis is moved in rapid traverse. Any number of straight movements could be programmed in the

Cartesian coordinate system (X, Y, Z). All programmed tracking axes are moved with linear velocity in such a manner that the start and the end of their movement take place simultaneously to that of the main axes.

Absolute dimensional input:

Nnnnn G00 G90 X120 Y80 U90 (traverse from P1 to P2)

Incremental dimensional input:

Nnnnn G00 G91 X80 Y60 U60 (traverse from P1 to P2)

Fig. 4-1: Positioning in rapid traverse

Special case: Alignment of a circular axis using G00 G90

If a rotatory axis is programmed through G00 with active G90 (G90: Absolute programming) the programmed target position is calculated in modulo. That means, that the rotatory axis moves a half-rotation in maximum.

Read more »

Rapid traverse G00

G00 Linear interpolation in rapid traverse

If G00 is selected, the rapid traverse speed of the axes specified in the machine parameters is used. Here, the resulting speed of the axes is given by the condition that at least one axis is moved in rapid traverse. Any number of straight movements could be programmed in the Cartesian coordinate system (X, Y, Z). All programmed tracking axes are moved with linear velocity in such a manner that the start and the end of their movement take place simultaneously to that of the main axes.

Absolute dimensional input:

Nnnnn G00 G90 X120 Y80 U90 (traverse from P1 to P2)

Incremental dimensional input:

Nnnnn G00 G91 X80 Y60 U60 (traverse from P1 to P2)

Fig. 4-1: Positioning in rapid traverse

Special case: Alignment of a circular axis using G00 G90

If a rotatory axis is programmed through G00 with active G90 (G90: Absolute programming) the programmed target position is calculated in modulo. That means, that the rotatory axis moves a half-rotation in maximum.

Read more »

G00 Positioning

 G00 Positioning

                                             The G00 command moves a tool to the position in the work piece system specified with in an absolute or an incremental command at a rapid traverse rate.

v                                                                      

•                 In the absolute command, coordinate value of the end point is   programmed.


• v        In the incremental command the distance the tool moves is programmed.

Format

 G00 X__ Z__

·         Nonlinear interpolation positioning

The tool is positioned with the rapid traverse rate for the each axis separately. The tool path is normally straight 

Read more »

Computer Numerical Control, CNC

CNC means Computer Numerical Control.

                        This means a computer converts the design produced by Computer Aided Design software (CAD), into numbers. The numbers can be considered to be the coordinates of a graph and they control the movement of the cutter. In this way the computer controls the cutting and shaping of the material.

CNC Coordinates    

                                  All the positions and motions of a computer numerical control (CNC) machine are understood in terms of numbers. Numbers describe the shape of the work piece, the movement of the cutting tool, the depth and speed of the cut, etc.

Figure 1

                                       How exactly are numbers used in this way? The common system used to describe location is called the Cartesian coordinate system, which consists of a cubic grid of imaginary lines. The Cartesian system defines the location of a single point in three-dimensional space using three axes, which are shown in Figure 1. These axes are called the X-axis, Y-axis, and Z-axis, and each one indicates a particular direction.

                                    An axis is an imaginary straight line. In the Cartesian system, the X-, Y-, and Z-axes meet at right angles. In other words, they join together like the corner of a box, as shown in Figure 2.

Figure 2

Read more »