Existing First in the CNC World
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.