Advanced machine tool programming is vital to Smiths Aerospace

Smiths Aerospace

Aerospace supplier relies on state-of-the-art machine tools such as five-axis mills and combination mill/turns to shrink manufacturing cycle time

• Customers’ tighter deadlines put the squeeze on manufacturing, which is finding ways to work faster through the use of advanced machine tools

Largest “non-major” aerospace company

Smiths Aerospace is a leading global aerospace equipment and systems company, with aerospace sales approaching $2 billion and more than 10,000 staff split between Europe and North America. The largest of the “non-major” (i.e. not Boeing, Airbus, etc.) aerospace companies, Smiths holds key positions in the supply chains of all major military and civil aircraft and engine manufacturers. The company’s mechanical systems business is strategically organized into seven product-focused global business units, one of which is the Landing Gear and Hydraulic Systems business unit located in Yakima, Washington. This unit specializes in landing gear extension and retraction systems, locking actuators and military stores management.

The Landing Gear and Hydraulic Systems business unit faces challenges common to all aerospace suppliers: speeding time-to-market and controlling costs. “Customers want products sooner, but they also want the capabilities of the tier-one vendors at small-shop prices,” says Bob Curwood, supervisor of NC programming for Landing Gear and Hydraulic Systems. Being involved in the manufacturing end of the business, Curwood is particularly aware of shrinking cycle times. “Most of the time-to-market is spent during the design phase, which means to meet the schedule the manufacturing cycle gets squeezed,” Curwood explains. He and his colleagues deal with this by investing in the most advanced equipment available, such as highspeed milling machines, five-axis milling machines and combination milling and turning (mill/turn) machines. “Our five-axis Mori Seiki machining centers and Mazak mill/turns make it possible for us to do what we need to in a reduced amount time,” says Axel Raptcheff, manufacturing engineering manager at Smiths. A mill/turn, for example, requires only one setup to perform four machining operations (initial milling, initial turning, finish milling and finish turning) that previously would have required four separate setups.

Programming advanced machines requires NX

The challenge with using such advanced manufacturing equipment is in the programming area. In Curwood’s experience, only NX is capable of generating accurate toolpaths for these state-ofthe- art machines. “We have evaluated other CAD/CAM systems, and NX has always provided the best functionality of any system available – and it can support any machine tool we need to support with its robust processing capabilities,” Curwood says. “NX Machining is absolutely the forefront of machining packages out there in industry today.” Curwood credits the NX Machining development team for this. “The Siemens PLM Software development staff includes some of the most experienced CAM technology experts in the industry, and they work with machine tool makers to support these advanced tools,” Curwood says. “Other vendors don’t seem to do this as well.”

NX CAM is key to one of Smiths’ time-saving strategies: the elimination of prototypes in favor of proving the NC program on production parts. Toolpath accuracy is just one part of this. NX machining simulation and visualization capabilities are also important. “With the ability to visualize the machine action and material removal, we can incorporate all the collision detection and prevention that is needed to make our ‘first-time parts’ approach work,” says Curwood. Because simulation and visualization capabilities are fully integrated with the NX application, it takes little time to set up a simulation. “The integrated software uses the same tool library and geometry we used to create our toolpaths, so setup time is minimal, and we don’t have to duplicate data in a separate simulation system.” Another benefit of the simulation is that programmers can use it to determine the best tools for the job. “Because we can now see where the chuck jaws are in relationship to the spindle face, we can choose the shortest tools possible – for example, to avoid vibration problems,” explains Curwood. “When a tool is too long, that leads to quality issues or we have to run the machine slower, so we’re getting benefits in both quality and speed.”

NC programmers in the Landing Gear and Hydraulic Systems unit frequently import CAD geometry from other Smiths sites into NX Machining. “Even though NX Machining can import and work with a wide variety of data in different formats for machining, there is no doubt that models that come from the NX design system, as opposed to others, are superior in terms of solid model integrity,” says Curwood. “This seems to be a feature of the strength of NX as a modeling system.”

Shorter setup times, no prototyping time

Thanks to its advanced machine tools and the ability to program them, the Landing Gear and Hydraulic Systems unit is shaving time off the manufacturing cycle in a variety of ways. One is by creating accurate toolpaths the first time, which eliminates one or two days of machine downtime every time an error is made. “When we had errors in the programs, we had to spend eight to 16 hours to go fix them; that’s machine downtime,” says Curwood. “We generate hundreds to a thousand NC programs a year, so by getting them right the first time, we’re saving a huge amount of time.”

Another way the unit is saving time is by not machining prove-out parts, which is only possible because the toolpaths are right the first time. Curwood points out, “Because we don’t allow ourselves a proving process, our toolpaths have to be right the first time. Not having to prove each program saves eight to 32 hours of machining time for each program, and this happens daily.” Finally, having advanced equipment such as the Mazak mill/turns saves time by eliminating setups. Because it is possible to program the mill/turns, four setups are compressed into one, which means setup time has dropped from a week to one day for some operations.

Curwood notes that as enhancements to NX come out, the Landing Gear and Hydraulic Systems unit saves processing time. “The algorithms get faster and better,” he says. “In some cases, adopting the latest release of NX has enabled us to reduce toolpath processing time by 10 to 15 percent.”

“With NX, we get consistent and error-free toolpaths, and we haven’t run across anything we couldn’t program with this software,” Curwood says. “By supporting state-of the-art machine tools, NX is a key element of how we’re speeding time-to-market.”

Related Links:

• Smiths Aerospace

Challenges:

• Adapt manufacturing processes to shrinking cycle times
• Control production costs

Keys To Success:

• Use advanced machine tools to reduce setup time
• Create toolpaths using NX™ Machining software
• Replace machined prototypes with computer simulation and go with "first-time parts"

Results:

• NX is only system that can accurately program advanced machine tools
• NX accuracy avoids waste of material and saves 8 to 16 hours of machining time per error
• Programming accuracy obtained with NX permits first-time parts
• Elimination of machining test runs saves 8 to 32 hours of machining time (on hundreds up to a thousand NC programs/year)
• Setup times decreased from a week to a day on combined milling and turning operations

Industry:

• Aerospace & Defense

Client's Primary Business:

Smiths Aerospace is a leading transatlantic aerospace equipment and systems company, with aerospace sales approaching $2 billion and more than 10,000 staff split between Europe and North America.

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Business Initiatives:

• Production Efficiency

Solutions/Services:

• NX
• NX CAM

Client Location:

Yakima, Washington
United States

"NX Machining is absolutely the forefront of machining packages out there in industry today. Every other system is a step backwards in time."

Bob Curwood

NC Programming Supervisor

Smiths Aerospace Mechanical Systems, Landing Gear and Hydraulic Systems