NCT Group NCT 990T - Manual (Page 115)

13.5 Automatic Mode Restart with BLOCK RETURN Condition
115
5
th
case: Return to interruption point machining in offset mode at outside corner
By the use of the BLOCK
RETURN condition
it states a perpendicular
vector on the interruption
point, the length of which
corresponds to that of the
new tool radius (supposing
the radius has been
changed) Afterwards the
machining is continued on
the tool path with the new
offset value from the inter-
ruption point.
When returning to inter-
ruption point of the block,
the control also returns on
the other axes. If tool length was also modified after tool replacement, it takes the new tool
length into account (see 1
st
case).
6
th
case: Return to interruption point machining in offset mode at inside corner
When condition BLOCK
RETURN is on ma-
chining inside a corner,
corresponds to that of a
outside corner. However
this time, as seen on the
diagram, if the interruption
occurred near the corner
and the radius of the new
tool is bigger than that of
the old one, it cuts into the
work. This can be sur-
mounted if the tool is not
led back fully to the inter-
ruption point, but is stopp-
ed earlier and condition
BLOCK RETURN is switched off. From than on it corresponds to the process dis-
cussed in the chapter “Unconditional Restart of Automatic Mode”. Another possibility is to
start a block search for the interrupted block, however this is the province of the following
chapter.