HEIDENHAIN TNC 410 ISO Programming - Manual (Page 66)

40 4 Programming: Fundamentals of NC, File Management, Programming Aids, Pallet Management
4.1 F
u
n
d
amen
ta
ls Polar coordinates
If the production drawing is dimensioned in Cartesian coordinates, you
also write the part program using Cartesian coordinates. For parts
containing circular arcs or angles it is often simpler to give the
dimensions in polar coordinates.
While the Cartesian coordinates X, Y and Z are three-dimensional and
can describe points in space, polar coordinates are two-dimensional
and describe points in a plane. Polar coordinates have their datum at
the pole. A position in a plane can be clearly defined by the
n
Polar Radius, the distance from the pole to the position, and the
n
Polar Angle, the size of the angle between the reference axis and
the line that connects the pole with the position.
See figure at upper right.
Definition of pole and angle reference axis
The pole is set by entering two Cartesian coordinates in one of the
three planes. These coordinates also set the reference axis for the
polar angle H.
Coordinates of the pole (plane) Reference axis of the angle
I and J +X
J and K +Y
K and I +Z
X
Y
0°
30
10
CC
R
H
1
H
2
R
R
H
3
X
Z
Y
X
Z
Y
X
Z
Y
I
J
K
K
J
I