On the surface, aerospace machining is pretty
straightforward: precision operations done a step at
a time. Although exacting, it’s frequently left-brain
work that’s comfortably predictable. It’s mostly pocket
milling, process monitoring and prescribed recordkeeping.
Or is it?
Arguably, no other sphere of manufacturing attracts so
many imaginative thinkers – big-picture types who ignore
trivia, but are passionate about essential details. They’re
innovators like Edvaldo Antonio da Rosa, the founder of a
cutting-edge Brazilian aerospace shop with a name that
evokes Japan – Toyo Matic.
Located in the southern city of Bragança Paulista, about
85 km north of São Paulo, Toyo Matic serves prominent
clients in the Americas, Europe and Asia. According to its
customers, Toyo Matic helps put Brazil on the map as a center
for modern precision machining. “That’s been our ambition
since day one,” says da Rosa, with a smile. “We love to hear
people say: ‘You can’t do that in Brazil!’”
The 20-year-old company earned its reputation by
routinely doing the nearly impossible. Although it boasts a
crew of 75 skilled machinists, operators, engineers and office
staff, Toyo Matic’s success reflects the drive and technical
talent of its energetic founder. With typical Brazilian humor,
associates declare that if da Rosa stepped into a revolving
door one space behind them, no one would be surprised to
see him exit first!
Not So Simple.
As prime aerospace manufactures strive to build with
weight-saving monolithic components, the “nearly
impossible” has become a common request. When Brazilian
aircraft manufacturer Embraer recently combined several
hydraulic control components for their popular ERJ-170/190
aircraft into a simpler monolithic unit, it proved to be
anything but simple to make.
After eight companies in three countries failed to find a
cost-effective way to manufacture the part, Embraer probably
started having second thoughts. Fortunately, the design
packet found its way back to Brazil – and Toyo Matic.
“It’s now the most difficult part we make,” confides da
Rosa. “It took many months of testing to develop the
procedures.” The heavily milled 7075 aluminum block
manifold has deep, intersecting blind holes, some as small as
2 mm diameter. Numerous other bores, recesses and curved
surfaces often require 6-micron tolerances, and it requires 160
individual CMM checks to generate the final 61-page
inspection report that accompanies each unit!
Toyo Matic solved many of the problems that baffled
others by optimizing their tooling to reduce the major causes
of inaccuracy: vibration, thermal growth and chip-induced
tool runout. “We’ve distilled the manufacturing process
down to only six operations,” da Rosa explains, “but we use
112 different tools!”
Finding the “technically sweet” tooling solution was a
creative effort well suited to da Rosa’s talents. Before
returning home in the 1980s to start Toyo Matic in Brazil, he
worked in Toyokawa City, Japan, for the large international
tool manufacturer, OSG Corporation. “I suppose,” he notes,
“that’s one of our secrets.”
Secrets Too Numerous
Instead of searching tool catalogs for the perfect solution,
da Rosa takes a more direct approach. “Whenever I have the
time, I always build my own tools,” he explains. “The
advantages are just too numerous to ignore.”
By making his own, da Rosa can optimize each milling
tool’s length-of-cut ratio for each operation – this usually
means producing the shortest possible tool to do the job.
Standard-reach tools are usable for a wide range of
operations, but their longer shafts make them prone to axial
runout, deflection and vibration. This is especially true when
subjected to the heavy side loads of aggressive pocket milling
– the most common scenario in an aerospace shop.
The traditional way around these problems is to slow the
feedrate. But that lengthens cycle time and can cause new
problems, especially in hard materials like titanium, where a
reduced feedrate can cause galling and work hardening. Also,
with the reduced chip load, heat can quickly build up at the
cutting edges, significantly shortening tool life. “Changing to
the proper length tool is the better solution,” offers da Rosa,
“even though the better solution isn’t always the obvious one.”
What about deep-reach situations where a longer tool is
required? Again, da Rosa’s optimized approach pays off. He
makes exact-length tools with an integral 40- or 50-taper base
that allows direct mounting in the machine spindle. By
eliminating the toolholder altogether, he bypasses a major
source of runout error. It is this kind of ingenuity motivation toward
precision that gives a shop the innovate edge in the CNC business.