Sandvik Coromant Silent tools - application guide - Manual (Page 31)

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2. Milling
The valve housing has a total length of 850 mm (33.46 inch) and a
production volume of 300 units per year. In January 2012 the valve
housing underwent a small process change. The length of the valve
housing demanded processing from both sides and the modifica-
tion involved finishing of the internal diameter of 140 mm (5.51
inch) with a maximum cutting length of 425 mm (16.73 inch).
The process was rationalized from two rough boring cuts, followed
by a flushing operation to remove chips before the final finishing to
Ø140 H7, to one circular interpolation and the final boring finish.
The milling adaptor, C8-391.05CD-27 360 was combined with a
basic holder and an oversized CoroMill 390, acquiring an assembly
length of 480 mm (18.9 inch).
By changing the process the customer saves EUR 22,000 per year.
This equals a payback time of nine weeks, or 64 produced
components. Another great bonus was that tool life increased
from two produced units to ten!
Step machining from one side
Reference Recommended
Step 1 Rough boring to diameter 135 mm
(5.31 inch) Circular interpolation to diameter
139.8 mm (5.50 inch)
Step 2 Rough boring to diameter 139.8 mm
(5.50 inch) Finishing boring to diameter 140 mm
(5.51 inch) H7
Step 3 Flushing
Step 4 Finishing boring to diameter 140 mm
(5.51 inch) H7