HEIDENHAIN CNC Pilot 4290 - Manual (Page 371)

HEIDENHAIN CNC PILOT 4290 359
7.5 Mac
hining P
a
ra
met
ers
Designations:
■ db1, db2: Drill diameter
■ DB1max/DB2max: Maximum inside diameter 1st/2nd drilling step
■ dimin: Minimum inside diameter
■ BBG – drilling limitation elements: Contour elements intersected
by UBD1/UBD2
■ UBD1/UBD2 have no effect when ”Centric predrilling”
has been defined as main machining operation followed by
”Finish-drilling” as submachining operation in the machining
sequence (see ”
6.12.2 Machining Sequence”).
■ Prerequisite: UBD1 > UBD2
■ UBD2 must permit subsequent inside machining with
boring bars.
■ Point angle tolerance [SWT] – If the drilling limitation element is a
diagonal element, TURN PLUS prefers using a twist drill with
suitable point angle.
SWT: Permissible point angle tolerance
If no suitable twist drill is available, an indexable-insert drill is
selected for the predrilling operation.
■ Drilling allowance – Diameter [BAX] – Machining allowance on
the drilling diameter (X direction - radius value)
■ Drilling allowance – Depth [BAZ] – Machining allowance on drilling
depth (Z direction)
BAZ is not considered if
■ A subsequent internal finishing cycle is not possible
because the diameter is too small.
■ During finish-machining blind holes,
”dimin < 2* UBD2.”