1. The gear manufacturer ’s dream !....
A cheap and multi - purpose tool ..
A flexible machine tool ...
Low table & axes speed ...
Cutting speed independent ...
Automatic tool change …
NO MORE SO EXPENSIVE HOBS !!!
11/27/2018
Fabio Sada

2. Geometrically correct Economically convenient
MILL YOUR GEARS !!!
Geometrically correct
Technically possible
Economically convenient
11/27/2018
Fabio Sada

3. MACHINING HARDWARE
NC machining center with rotary table and indexable square - head
standard thin milling tool dia
eventually 2 milling tools spaced of 1 normal basic step
11/27/2018
Fabio Sada

4. SETUP gear placed approximately in center of table
tool axe indexed as basic helix angle
tool front edge on a plane tangent to basic cylinder
11/27/2018
Fabio Sada

5. THE ROLLING LAW Table rotation = 360 dg
Tool movement = * Basic Diameter
11/27/2018
Fabio Sada

6. MACHINING / mode A CONTINOUS MODE: The gear rotates
The milling tool front center moves on a traverse section, on a plane tangent to basic cylinder
Both are Synchronized as by Rolling Law
11/27/2018
Fabio Sada

7. MACHINING / mode B MULTI - CUT MODE
Sequence of gear/tool positions according to Rolling Law
Execute local micro -planes
11/27/2018
Fabio Sada

8. Geometry errors / mode A
CONTINOUS MODE:
2nd arrow due to axial step, minimum curvature radius and tool position
11/27/2018
Fabio Sada

9. Geometry errors / mode A
Continuos mode:
When axial step lowers , errors lower too
11/27/2018
Fabio Sada

10. Geometry errors / mode B
MULTI - CUT mode :
Out - tool due to number of cuts
11/27/2018
Fabio Sada

11. ADVANTAGES / gear any module any pressure angle any tooth height
narrow central groove
partial machining
IMMEDIATE MACHINING OF ANY GEAR
11/27/2018
Fabio Sada

12. ADVANTAGES / Machine tool
flexibility
less many NC controlled axes
Low table speed or stopped
Low damages in case of sudden power failure
11/27/2018
Fabio Sada

13. ADVANTAGES / tool multi - purpose no twin L / R tools low cost
immediate delivery
large choice of inserts shape and quality
cheap inserts
a lot of suppliers
cutting speed independent and uniform
low damages in case of power black-out
cutting angles optimized
good chip production and removal
lower precision performances
double tool is possible
11/27/2018
Fabio Sada

14. ADVANTAGES / machining
gear placed approximately in center of table
easy reference surface centering
light - weight tool & automatic tool change
spare tools in tools store
insert change while machining
NO re-sharpening
chips removal while table turns slowly
low cutting forces
immediate and constant chip removal
milling of hardened gears
immediate stop rotation without problems
11/27/2018
Fabio Sada

15. AT THE END ... Believe and try !!!
For large modules hobbing technology is expensive and not optimal
Believe and try !!!
11/27/2018
Fabio Sada

16. bye Fabio Sada Via San Pancrazio 20 - 20060 GESSATE (MI) - ITALY
11/27/2018
Fabio Sada