Selecting The Preset - HEIDENHAIN TNC 640 User Manual

4

Selecting the preset

A production drawing identifies a certain form element of the
workpiece, usually a corner, as the absolute preset (datum). When
setting the preset, you first align the workpiece along the machine
axes, and then move the tool in each axis to a defined position
relative to the workpiece. Set the display of the control either to
zero or to a known position value for each position. This establishes
the reference system for the workpiece, which will be used for the
control's display and your part program.
If the production drawing is dimensioned in relative presets, simply
use the coordinate transformation cycles.
Further information:
If the production drawing is not dimensioned for NC, set the
preset at a position or corner on the workpiece from which
the dimensions of the remaining workpiece positions can be
measured.
The fastest, easiest and most accurate way of presetting is by
using a 3-D touch probe from HEIDENHAIN.
Further information:
page 722
Example
The workpiece drawing shows holes
are shown with respect to an absolute preset with the coordinates
X=0 Y=0. The coordinates of holes
preset with the absolute coordinates X=450 Y=750. By using
the Datum shift cycle you can shift the datum temporarily to the
position X=450, Y=750 and program the holes
further calculations.
156
Cycle Programming User's Manual
"Presetting with a 3-D touch probe ",
(1 to 4), whose dimensions
5 to 7 refer to the relative
(5
Fundamentals, File Management | Fundamentals
to 7) without
HEIDENHAIN | TNC 640 | ISO Programming User's Manual | 10/2017