Touch Probe)
Note
You fix a datum by setting the TNC position display to the coordinates of a known position on the workpiece.
Preparation
U UU
UClamp and, if required, align the workpiece.
U UU
UInsert the zero tool with known radius into the spindle.
U UU
UEnsure that the TNC is showing actual position values.
For datum setting with a 3-D touch probe, refer to the Touch Probe Cycles Manual.
2.4 D a tu m Set ting (With out a 3 -D T ouc h Pr ob e)
Datum setting
Select the Manual Operation mode.
Move the tool slowly until it touches the workpiece surface.
Select an axis (all axes can also be selected via the ASCII keyboard).
Zero tool in spindle axis: Set the display to a known workpiece position (here, 0) or enter the thickness d of the shim. In the tool axis, offset the tool radius.
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.
Fragile workpiece?
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.
DATUM SET Z=
Y
X Z
X Y
54 2 Manual Operation and Setup
2.4 D a tu m Set ting (With out a 3 -D T ouc h Pr ob e) Datum management with the preset table
You should definitely use preset tables if:
nYour machine is equipped with rotary axes (tilting table or swivel head) and you work with the tilted working plan function
nYour machine is equipped with a spindle-head changing system
nUp to now you have been working with older TNC controls with REF-based datum tables
nYou wish to machine identical workpieces that are differently aligned
Preset tables can contain any number of lines (datums).
To optimize the file size and the processing speed, you should use only as many lines as you need for datum management.
For safety reasons, new lines can be inserted only at the end of the preset table.
2.4 D a tu m Set ting (With out a 3 -D T ouc h Pr ob e)
Saving the datums in the preset table
The preset table has the name PRESET.PR, and is saved in the directory TNC:\. PRESET.PR is editable only in the Manual and El.
Handwheel modes. In the Programming and Editing mode you can only read the table, not edit it.
There are several methods for saving datums and/or basic rotations in the preset table:
nThrough probing cycles in the Manual or El. Handwheel modes (see User’s Manual, Touch Probe Cycles, Chapter 2)
nThrough the probing cycles 400 to 402 and 410 to 419 in automatic mode (see User’s Manual, Touch Probe Cycles, Chapter 3)
nBy adopting the current datum, which you set manually with the axis keys
Explanation of values saved in the preset table nSimple machine with three axes without tilting device
The TNC saves in the preset table the distance from the workpiece datum to the reference point (including algebraic sign, see figure at upper right)
nMachine with swivel head
The TNC saves in the preset table the distance from the workpiece datum to the reference point (including algebraic sign, see figure at center right)
nMachine with rotary table
The TNC saves in the preset table the distance from the workpiece datum to the center of the rotary table (including algebraic sign, see figure at lower right)
Manual entry of values in the preset table is allowed only if there are no tilting devices on your machine. An exception to this rule is the entry of basic rotations in the ROT column. The reason is that the TNC compensates the geometry of the tilting device when it saves values in the preset table.
When setting a datum, the TNC checks whether the position of the tilting axes match the corresponding values of the 3D ROT menu (depending on Machine Parameter 7500 bit 5). Therefore:
nIf the “Tilt working plane” function is not active, the position displays for the rotary axes must = 0° (zero the rotary axes if necessary).
nIf the “Tilt working plane” function is active, the position displays for the rotary axes must match the angles entered in the 3D ROT menu.
The machine manufacturer can lock any lines in the preset table in order to place fixed datums there (e.g. a center point for a rotary table). Such lines in the preset table are shown in a different color (default: red).
56 2 Manual Operation and Setup
2.4 D a tu m Set ting (With out a 3 -D T ouc h Pr ob e)
Editing the preset tableEditing function in table mode Soft key Select beginning of table
Select end of table
Select previous page in table
Select next page in table
Release/lock preset table for editing
In the selected line of the preset table, save the datum that is active in the Manual operating mode
Activate the datum of the selected line of the preset table
Add the entered number of lines to the end of the table (2nd soft-key row)
Copy the highlighted field (2nd soft-key row)
Insert the copied field (2nd soft-key row)
Reset the selected line: The TNC enters – in all columns (2nd soft-key row)
Insert a single line at the end of the table (2nd soft-key row)
Delete a single line at the end of the table (2nd soft-key row)
2.4 D a tu m Set ting (With out a 3 -D T ouc h Pr ob e)
Activating the datum from the preset table in the Manual operating mode
Select the Manual Operation mode.
Call the function for setting the datum.
Call preset table.
Release the preset table for editing: Set the EDIT OFF/ON soft key to ON.
With the arrow keys, select the datum number that you want to activate, or
With the GOTO key, select the datum number that you want to activate. Confirm with the ENT key.
When activating a datum from the preset table, the TNC resets all coordinate transformations that were activated with the following cycles:
nCycle G53, Datum shift in datum table nCycle G54, Datum shift in program nCycle G28, Mirroring
nCycle G73, Rotation nCycle G72, Scaling
However, the coordinate transformation from Cycle G80, Tilted Working Plane, remains active.
DATUM SET X=
Activate preset
Confirm activation of the datum. The TNC sets the display and—if defined—the basic rotation
Leave the preset table
Activating the datum from the preset table in an NC program Use Cycle G247 in order to activate datums from the preset table during program run. In Cycle G247 you simply define the number of the datum to be activated (see “DATUM SETTING (Cycle G247)” on page 384).