Polar Coordinates; Absolute And Incremental Dimensions - Siemens SINUMERIK 840D sl Operating Manual

Creating a ShopMill program
9.3 Fundamentals
Working planes
Working planes are defined as follows:
Plane
X/Y
Z/X
Y/Z
9.3.2

Polar coordinates

The rectangular coordinate system is suitable in cases where dimensions in the production
drawing are orthogonal. For workpieces dimensioned with arcs or angles, it is better to define
positions using polar coordinates. This is possible if you are programming a straight line or a
circle.
Polar coordinates have their zero point at the "pole".
Example
Points P1 and P2 can then be described – with reference to the pole – as follows:
P1: Radius =100 / angle =30°
P2: Radius =60 / angle =75°
9.3.3

Absolute and incremental dimensions

Absolute dimensions
With absolute dimensions, all the position specifications refer to the currently valid zero point.
Applied to tool movement this means: The absolute dimension data defines the position, to
which the tool is to travel.
278
Tool axis
G17 Z
G18 Y
G19 X
Operating Manual, 05/2017, A5E40868956
Milling