time is money

March 1, 2002
An HMC helps an aerospace firm prove that the old adage is truer than ever.

An HMC helps an aerospace firm prove that the old adage is truer than ever.

Aero's cell has a 12-station pallet stocker and a rail-guided vehicle that loads and unloads the machine. This arrangement lets the company fixture off-line and load the fixtures into the stations while the FA800 HMC is running.

Toyoda's FA800 horizontal machining center, which traverses in all axes at 944 ipm, delivers feedrates from 0.04 to 944 ipm. Its X, Y, Z travel is in.

The FA800's trunnion table combines a tilting A axis, which provides 115° of rotation, and a rotary B axis.

A separate cell controller, which integrates with the FA800's machine control, directs the system's loading and unloading operations.

Aero's FA800 has a 120-tool magazine.

Five-axis capabilities let Aero slash machining time for parts such as this landing-gear component.

Aero President Marcel Desjarlais holds a steel cylinder that is produced on the FA800. The company fixtures it off-line, then loads the fixture onto one of 12 waiting pallet stations.

Aero Machining Ltd. is no stranger to axis work. The shop, which supplies aerospace components to customers such as Bombardier and Boeing, regularly uses 5-axis machines to make a variety of large, heavy workpieces. But, until recently, all these parts were made on vertical machining centers. That changed when the company added a 5-axis horizontal machining center. The HMC, says Aero, easily handles heavy cuts that would make a VMC balk, but, even more importantly, it reduces setups. With the extra time this provides, the shop gains an important edge: the capacity to take on new jobs.

The Montreal firm has served the aerospace industry for nearly 40 years. According to President Marcel Desjarlais, Aero has a reputation for quality work and the capability to tackle jobs that other shops can't. But it had hit the wall when it came to capacity. The HMC, though, gave it both the time and flexibility it needed to overcome this problem.

The machine, a FA800 from Toyoda Machinery USA, Arlington Heights, Ill., combines the speed and power required for Aero's large and heavy workpieces, including 4340 steel and 7075 and 7475 aluminum landing gear and wing parts. The machine sports a trunnion-table design combining a tilting A axis, which provides 115° of rotation, and a rotary B axis. With the fourth and fifth axes integrated into the table, the 14,000-rpm spindle head remains fixed. This configuration provides maximum stiffness, allowing a workpiece to be closely positioned to the spindle, without limiting Y-axis capacity.

Toyoda customized Aero's HMC with a rail-guided vehicle and a 12-station pallet stocker controlled by a cell controller that works in concert with the machine control. Aero does all its fixturing off-line and loads the fixtures into the stations. The RGV system then loads and unloads the machine.

"The Toyoda lets us run 12 pallets," says Production Manager Marco Leonardi. "We might have three or four pallets dedicated to one part number. All we do is call up the pallet, put on the part, and the machine does the rest."

The pallet-system controller directs all pallet changes. An operator punches in what pallets are needed — for example, #2, #4, #5, and #8 — and in which order. Once the machine is running, the operator is free to set up another job. The system also gives the operator flexibility for rush jobs.

"In this case, the operator calls up an empty pallet, say #12, makes the setup, and calls up the job on the controller. Instead of bringing up #4, as we originally planned, it picks up #12 and starts the program. When it's finished, the system returns to the planned order: #4, #5, and #8."

Currently, Aero runs only four parts on the machine. "The machine is fairly new, so we're still learning about its capabilities. Eventually, we want all 12 pallets working. But for now, we have four major parts rotating — an aluminum A-frame for the Boeing 717, a steel cylinder for RF Goodrich, a steel bracket for Bombardier, and aluminum landing gear for Boeing."

Aero finishes all but the last component in one setup on the HMC. According to Leonardi, the only reason the landing gear takes two operations is because it's removed for heat treating and then returned to the machine for finishing.

"Our goal is to have one setup," comments Leonardi. "This reduces both time and cost." For the most part, Aero determines what parts run on the FA800 based on cycle-time reduction. "Obviously, we look at part complexity — what parts must be done on a 5-axis machine. The jobs that go on the Toyoda are ones we can do in a single setup, from A to Z. These jobs would require three or four setups on other machines."

On one component, for example, Aero slashed 10 hr off machining time by moving from several setups to just one on the Toyoda. What previously took 22 hr to complete through conventional methods now takes only 12. Quality-wise, the HMC eliminates much of the hand deburring that Aero had to perform. "We do the deburring right on the machine," says Desjarlais. And the FA800 repeatedly provides 0.0001-in. tolerances. "The machine ensures that the part comes out the same way from the first to the last piece," he confirms.

Programming is simple. Operators simply download a program from a central PC on the shop floor to the control, a GE Fanuc 16i CNC that delivers a high-capacity control memory, Nurbs interpolation, and remote-diagnostics capabilities. Remote diagnostics, in fact, was one of the key factors that swayed Aero toward the Toyoda machine.

"Service is also important to us," says Leonardi, "and Toyoda's has been impeccable." If Aero has a problem with the machine, Toyoda quickly pulls up the machine information over the phone to see if it's an error message, a programming glitch, or a mechanical problem that requires a service person to come to the facility. The end result is faster diagnosis and less machine downtime.

Why 12 pallets?
Although Aero is not currently using all 12 pallet stations, it had reasons for wanting them. The company plans to add a 4-axis HMC to the existing line to further streamline its operations. "Now, our 5-axis work is only 15% to 20% of the machine time on the FA800," explains Desjarlais. "Our intention is to do all the 3 and 4-axis work on another machine and use the FA800 strictly for the 5-axis work."

This makes a lot of sense, says Bob Couville, regional manager for Toyoda. "The existing machine can be dedicated to the most complex jobs that require the range of motion available with the fifth axis. Then Aero can add a 4-axis machine with maybe a 6,000-rpm spindle that will really hog out material. Both will operate on the same cell, with jobs routed to the best machine. Or the 4-axis could rough a part out and then hand it off for the 5-axis work."

This 4-axis machine would use the same 12-pallet stocker, cell controller, and RGV as the FA800. "We would have two spindles, 12 pallets, and only one operator," says Leonardi. In the meanwhile, however, Aero has the expansion slots in place for any new jobs that come its way.

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