HEIDENHAIN CNC Pilot 4290 - Manual (Page 339)

HEIDENHAIN CNC PILOT 4290 327
Abbreviations
SBI: Cutting limitation, inside
SU: Roughing limitation (SU = sbl + ULI)
sbl: Basic length of roughing cut (”deepest” point of inside contour)
ULI:Overhang length, inside (machining parameter 4)
nbl: Usable tool length (tool parameter)
6.16 Mac
hining Inf
or
mation
Limits for internal machining operations
■ Predrilling
SBI limits the drilling operation.
■ Roughing
SBI or SU limit the roughing operation.
SU = basic length of roughing cut (sbl) + overhang length, inside
(ULI)
To avoid ”residual rings” during the machining process, TURN PLUS
leaves an area of 5° in front of the roughing limit.
■ Finishing
sbl limits the finishing operation.
The illustrations show the dimensions (a), the drilling operation (b), the
roughing operation (c) and the finishing operation (d).
Example 1
The roughing limit (SU) is in front of the inside cutting limit (SBI).
Example 2
The roughing limit (SU) is behind the inside cutting limit (SBI).