Machining Exotic Materials in One Setup

Falcon Precision Industries, Inc. specializes in machining complex aerospace components in prototype and low production quantities. To do the needed 5-axis work on these parts requires making special devices for holding the workpiece in a fixed position so the cutting tool could get at pockets, contours and all sides of the part.

"We have three Mazak Variaxis 630 machining centers with full 5-axis machining capabilities and we are awaiting delivery of our fourth one," reports John Blankenship, manager of manufacturing engineering for Falcon Precision. "To do the required 5-axis machining of our aerospace parts on these machines, we designed custom clamping devices to hold these complex parts. We didn't use conventional vises and workholding as the primary holding device because it restricted the machining center to just three axes."

That meant setting up the part and running the machine in a 3-axis mode, stopping to reposition the part and then running the last two axes, defeating the purpose of having 5-axis capability. That was too slow and tedious, so Blankenship and his toolmakers came up with special dedicated holding fixtures to allow for the 5-axis work. "This was a more productive way to machine in all five axes," he says, "until we discovered Kurt's 5-axis vise. It gave us a more flexible and faster way to set up and clamp parts for our demanding 5-axis work."

John Blankenship, machining supervisor for Falcon Precision Industries, Inc., shows off a complex aerospace part 5-axis machined in a single setup made possible using the new Kurt VB 5AX100 Schenke 5.1 clamping system shown in the background.

"Scott Lundin, senior manufacturing engineer of Falcon Precision, saw the new Kurt 5-axis vise at a recent Mazak open house," Blankenship reports. "The vise was mounted on one of the pallets of a Variaxis machine. While the vise did not have a part in it, Lundin could easily see several benefits of this type of clamping system."

Complex Aerospace Projects

True 5-axis contour machining is a rapidly growing technology embraced by Falcon Precision Industries for its growing list of aerospace customers. With a 20-year history in contract precision parts manufacturing, this ISO 9001:2000 and AS9100 Rev B company recognizes the long-term growth opportunities in serving aerospace and other demanding industries with the latest, most cost effective technology available.

Simultaneous 5-axis machining has numerous benefits, as Blankenship observes. "It provides continuous, high speed 5-axis imaging which is ideal for profiling parts. It's perfect for machining deep cavities and corners. Plus it is highly consistent for tighter tolerances while surface finishes are better. And you can accomplish all this in a single machine setup."

Falcon Precision machines virtually all materials used for aerospace parts, everything from Inconel and Titanium to various grades of aluminum. Clamping rigidity is of concern for both extremes: smaller parts machined from harder materials and larger parts machined from softer material. Using its custom clamping devices held in standard vises and/or mounted directly on the Mazak Variaxis table that rotates 380° (C-axis) and tilts 150° (A-axis), Falcon Precision's setup technicians devised appropriate rigidity and clamping pressure basically using set screw devices.

Workable as this method was, the addition of the Kurt 5-axis vise provides a much faster part setup with more consistent and predictable clamping pressures and the rigidity needed for both small and large parts of both hard and soft metals. This versatility is especially helpful with the low part runs and frequent setups.

Ideal Alternative

"Once mounted on the machine worktable, the Kurt 5-axis vise sets up for different jobs in just 10 to 15 minutes compared to as much as 2½ hours using our custom clamps," Blankenship reports. "We use the two sets of supplied Kurt jaws (round and flat), set the movable and stationary jaw, and we're ready to run the job. It's really versatile. Our setup man loves it!"

The Kurt 5-axis vise is adjustable to handle any desired clamping width, so it is limited only by the size of the Mazak's machine table. With two clamping jaws, one stationary and one movable, the jaws can be positioned at any desired distance from each other.

Actual clamping width for this Kurt system is 0.0787" to 9.291" (2mm to 236mm) that can be extended with optional spindle screws, a clamping depth of 0.315" (8mm), height above the machine table of 6.889" (175mm) with extended height options to 7.874" (200mm) and 8.858" (225mm).

A typical job using the new vise runs at up to 12,000rpm and at 130ipm, depending on the tools used, according to Blankenship. The system is designed to mount easily on standard T-slot tables, location grid machine tables or custom fixtures. For Falcon Precision, it sets up like a standard vise on the Mazak's tilting rotary table in about the same amount of time - less than 15 minutes. The 5-axis vise stays mounted on the table with the second pallet used for secondary operations or other projects. The big thing with Falcon Precision's application is that it can handle virtually all of its complex aerospace parts without any add-on jaws, spacers or devices with set screws.

System Pays For Itself

Blankenship and his highly skilled machinists Joe Kenyon and Glen Balon say they really like the rigidity of the Kurt 5-axis Schenke clamping system, which was proven on the first project. "We're getting ±0.001" angularity tolerances running carbide and other standard tool inserts up to 12,000rpm with cuts up to 130rpm. We've never had a problem with tool chatter or part misalignment at these speeds. The rigidity with this vise has exceeded our expectations, and we're finishing jobs in half the time or less compared to before. The vise paid for itself the first month we used it," Blankenship says.

Using the Unigraphics CAD program, Falcon Precision simulates the workblank and finish-machined part held in the Kurt 5-axis vise.

Virtually any shaped part can be machined as these two Falcon precision part projects show, using the new Kurt 5-axis vise.

The reason for this rigidity is that the Kurt 5-axis Schenke clamping system's design eliminates jaw deflection and/or part misalignment during these high speed operations. By locating the tension spindle directly under the workpiece, the clamping system's jaws do not flare out under tension and the machine table does not distort like conventional workholding. Also, the system handles a full range of workpiece configurations with equal rigidity including blank, machined, round and irregular shapes with repeatable accuracy.

"The Kurt 5-axis Schenke clamping system has been an important upgrade for our overall machining operations," Blankenship says. "We've eliminated the need for all of those special clamping devices and we've reduced production time by as much as half with no scrapped parts. And we're finishing jobs in half the time or less compared to before. The vise paid for itself the first month we used it. We've ordered our third Kurt 5-axis vise and are planning to use the two in tandem for holding even larger parts."

In addition to the 5-axis Schenke clamping system, Kurt provides integrated custom engineered workholding systems and custom gaging systems for automated manufacturing. Both workholding and gaging are designed around a customer's requirements with systems available for many industries including automotive, medical and aerospace applications.