The company
estimates payback on its die-casting
investment will take only six
months.
“Most of these components are
produced by traditional machining
from plate or bar stock,” explains
Anritsu Process Engineer
Sam Krull. “Because we’re a lowvolume
manufacturer, we sometimes
don’t have the opportunity
to use less-expensive production
techniques. But we’ve seen payback
in these parts in as little as
three months.”
Anritsu worked with Alloy Die
Casting Corp. (ADC), Buena Park,
Calif., to develop the A380 die-cast
aluminum parts. “The shields
are fairly complex, which makes
some casting houses shy away
from smaller production runs,”
says ADC Design Engineer Gary
Gray. “Some shields are just 0.03-
in. thick. And any time an alumnum casting gets below 0.06 in.,
you can run into complications.
So it’s important to get the right
balance of injection speed and
venting capacity, as well as precise
temperature control.”
The shields are cast from single-
cavity tools, typically on a
250-ton press. The molten 1,200°F
alloy goes through a small 2-in.
plunger that fills the die in about
25 msec. The process, however,
maintains a relatively low gate velocity,
around 1,200 ips. Depending
on the type of shield, shot
sizes range from 4 oz
to about a pound.
“We typically run at
a conservative speed
of 70 and 80 cycles/hr,”
says Gray. “We want
the injection to be
fast enough to fully
atomize the material
and give us a quick fill
time. But we have to
temper that with the
understanding that
higher gate velocities
erode tool steel
more quickly and can
shorten die life.”
Finishing operations
for the shields
include straightening
and about 6 min
of machining, drilling,
and tapping on
a single-spindle CNC
manufacturing center
for up to 19 throughholes
(two of which
are threaded) on each
shield.
“Drilling the holes
rather than casting
them in place helps
us maintain closer tolerances
and minimize
pin breakage,” Gray
says. “If we were running
large quantities
at a time, we’d consider
a multispindle drill operation,
but in these volumes, drilling
one at a time is still efficient.” The
shields then go out for anodizing
to help prevent corrosion.
Make Contact
Alloy Die Casting Corp., (714) 512-
9800, alloydie.com
Anritsu Co., (408) 778-2000, www.anritsu.com