LIEBHERR MODEL LC 255 HEAVY DUTY CNC GEAR HOBBING

AND OTHER WORKPIECES WITH SIMILAR PROFILES
CAPACITY DATA
Maximum workpiece diameter10" 250mm
Maximum pitch (86000 psi steel)4" Modul 6
Maximum hob slide travel10" 250 mm
Work table diameter10" 250 mm
Master worm wheel, pitch diameter11.2" 285 mm
Minimum distance between hob and table center.78" 20 mm
Maximum distance between hob and table center8.1" 205 mm
Maximum hob diameter5.7" 145 mm
Maximum hob length7.9" 200 mm
Maximum tangential travel (shifting)6.7" 170 mm
Hob spindle speed ranges60 - 360 RPM
or80 - 480 RPM
or100 - 600 RPM
Rapid travel axial39.4 IPM 1000 mm/min
radial63 IPM 1600 mm/min
tangential9.8 IPM 250 mm/min
Feed ranges axial .004 - .472 IPR .1 - 12 mm/rev
radial .004 - .157 IPR .1 - 4 mm/rev
tangential .0004 - .197 IPR .01 - 5 mm/rev
Machine weight11,500 lbs

MOTOR SPECIFICATIONS

19 HP, 14 KVA Main motor
BASIC MACHINE
Machine bed with stationary table assembly, table spindle with anti-
friction roller bearings
Two-start indexing gear, worm wheel of bronze, dual lead worm
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BASIC MACHINE
Machine main column with infinitely variable radial feed, automatically
locked in working position
Tailstock column with hydraulically actuated tailstock arm,
automatically locked in working position
Hob head swivel with automatic clamping/unclamping of hob head
Separate drives for hob spindle and work table
Ball screws, pre-loaded recirculating for axial, radial, and
tangental feed
Automatic clamping/unclamping of hob arbor, controlled form
operator's panel
LIEBHERR CNC CONTROL SYSTEM MPST
CNC full contouring control for 6-axis
Radial movement
Axial movement
Tangential movement
Hob rotation
Table rotation
Hob head swivel
Hob and table rotation is integrated in the CNC system
Linking of axial hob slide movement and table rotation
Linking of tangential movement and table rotation are integrated in
the CNC system
Page 3 of 3
AND OTHER WORKPIECES WITH SIMILAR PROFILES
LIEBHERR CNC CONTROL SYSTEM MPST
Copy system for crowning and end relief are part of the CNC system,
(linkage of radial and axial motion. Linear and circular
interpolation, maximum, radius 328, 100 m)
Feeds programmable in mm or inches/table revolution, feeds constant
with changes in hob speed. When single-indexing milling, feed in
mm or inch/min
Separate overrides for feeds and speed (infinite between 10 and 133%)
Altering of feed and speeds during hobbing allows optimization of
the outting condition
CNC system, free programmable for individual cycles, input via
keyboard or punch tape
Parametric programming with 90 variable and 10 fixed parameters
Parametric programs for 32 fixed cycles repeatedly used for hobbing
One cut cycle
Two cut cycle
With or without radial approach, climb or conventional hobbing
hobbing with or without shifting. Radial or tangential hobbing.
Fixed cycles for crowning and taper hobbing. Programs include
degressive approach.
Software for calculation of approach, overrun and crowning data
(crowning radius and radius location)
CMOS technique for approximately 50 part programs (components),
depending on complexity of program (16,000 characters).
Expansion to 32K against extra charge.