HEIDENHAIN TNC 620 User Manual page 252

6
Danger of collision!
During an automatic tool change with M101, the control always
retracts the tool in the tool axis first. There is danger of collision
when retracting tools for machining undercuts, such as side
milling cutters or T-slot milling cutters!
Deactivate the tool change with M102
After the tool change the control positions the tool according to
the following logic, unless otherwise specified by the machine tool
builder:
If the target position in the tool axis is below the current
position, the tool axis is positioned last
If the target position in the tool axis is above the current
position, the tool axis is positioned first
Depending on the NC program, the machining time can increase as
a result of the tool life verification and calculation of the automatic
tool change. You can influence this with the optional entry element
BT (block tolerance).
If you enter the M101 function, the control continues the dialog by
requesting BT. Here you define the number of NC blocks (1 - 100)
by which the automatic tool change may be delayed. The resulting
time period by which the tool change is delayed depends on the
content of the NC blocks (e.g. feed rate, path). If you do not define
BT, the control uses the value 1 or, if applicable, a default value
defined by the machine manufacturer.
The higher the value of BT, the smaller will be the effect
of an extended program duration through the M101
function. Please note that this will delay the automatic
tool change!
Use the formula
of an NC block in seconds
starting value for BT. Round up to the next integer. If the
calculated result is greater than 100, use the maximum
input value of 100.
If you want to reset the current age of a tool (e.g. after
changing the indexable inserts), enter the value 0 in the
CUR_TIME column.
252
NOTICE
BT = 10: Average machining time
to calculate a suitable
HEIDENHAIN | TNC 620 | Conversational Programming User's Manual | 10/2017
Tools | Tool data