Datum Setting Without A 3-D Touch Probe - HEIDENHAIN TNC 620 User Manual

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Datum setting without a 3-D touch

Setting the datum with a 3-D touch probe: See

"Datum Setting with 3-D Touch Probe (Touch Probe

Function Software Option)", page 479.

You fix a datum by setting the TNC position display to the

coordinates of a known position on the workpiece.

Clamp and align the workpiece

Insert the zero tool with known radius into the spindle

Ensure that the TNC is showing the actual position values

Workpiece presetting with axis keys

Protective measure

If the workpiece surface must not be scratched, you

can lay a metal shim of known thickness d on it.

Then enter a tool axis datum value that is larger than

the desired datum by the value d.

Select the MANUAL OPERATION mode

Move the tool slowly until it touches (scratches)

the workpiece surface

Select the axis

DATUM SETTING Z=

Zero tool, spindle axis: Set the display to a known

workpiece position (here, 0) or enter the thickness

d of the shim. In the machining plane: Take the

tool radius into account

Repeat the process for the remaining axes.

If you are using a preset tool, set the display of the tool axis to the

length L of the tool or enter the sum Z=L+d

The TNC automatically saves the datum set with the

axis keys in line 0 of the preset table.

TNC 620 | User's Manual

HEIDENHAIN Conversational Programming | 3/2014

Datum setting without a 3-D touch probe 14.5