Korean builder unveils advanced technology

Korean builder unveils advanced technology


The DMV 5025 heavy-duty, high-volume VMC sports Daewoo's new spindle-drive belt-and-pulley setup that reduces heat and noise.

Daewoo's Puma TT 2000s feature twin spindles and twin turrets — both spindles and both turrets deliver equal capacity.

As an inverted vertical turning center with traveling headstock and fixed turret, Daewoo's Puma Inverturn 300 delivers loaderless automation.

As a multi-axis turning center, Daewoo's Puma MX 2000 includes a milling spindle with B-axis rotation for Y-axis machining.

The FV 400 VMC with 2-G acceleration and 35,000-rpm spindle is one of Daewoo's concept machines featuring linear-motor axis drives.

(photo courtesy of Paine Machine Tool, Delta, B.C.)

HIGH SPEED, PRECISION, AND productivity were the overriding themes at the fourth Daewoo International Machine Tool Fair (DIMF) held in Changwon, South Korea. Daewoo treated both its distributors and customers to a showing of 54 machining systems, among which were new VMCs, HMCs, turning centers, and soontobe-released concept machines.

In the VMC section, three new heavy-duty, high-volumeproduction machines took center stage. The first two, the DMV 5025 and DMV 5025/50, incorporate Daewoo's new spindle-drive beltand-pulley setup that reduces heat and noise. Available spindles are a 40-taper, 12,000-rpm, 20-hp model and a 50-taper, 8,000-rpm, 20-hp one.

Built on rigid C frames, the two machines rapid traverse at 945 ipm in X and Y and 787 ipm in Z. They also feature cam-driven automatic toolchangers that hold 24 tools.

The third VMC was the highspeed, traveling-column DVC 400. The machine sports a 40-taper, 25-hp, 10,000-rpm (12,000-rpm optional) direct-coupled spindle; a Y axis measuring 400 mm; and 1,575-ipm rapid traverse. Servomotor power unclamps tools, and the 400's cartridge-type spindle provides easy maintenance. Also featured was a dual-table-type automatic pallet changer.

New Daewoo HMCs drawing attention were the DHP 5000, DHC 500, and DB 250C. Featuring a 500-mm pallet and 40-taper directcoupled spindle, the DHP 5000 provides axis strokes measuring 850, 700, and 750 mm for X, Y, and Z, respectively, along with a rapid traverse of 48 m/min.

The machine's 12,000-rpm (14,000-rpm optional) spindle sports an extended cooling jacket and three-point balancing at the front, coupling, and motor end. A cam-driven toolchanger and servodriven magazine make for a 1.5-sec tool-to-tool change time, while the machine's rotary-shuttle automatic pallet changer indexes in 8 sec.

Like DHP 5000s, DHC 500s pack 500-mm pallets and 40-taper, directcoupled spindles with extended cooling jackets and three-point balancing. Spindles turn up to 10,000 rpm, and axis travels measure 850 mm in X, 700 mm in Y, and 750 mm in Z.

Daewoo's DB 250C is a horizontal CNC travelingcolumn boring and milling machine for high-volume, wide-axis applications. It features a 6,000-rpm, quilltype, high-speed spindle head with six bearings for support and a W-axis clamping device that holds with hydraulic power.

Machine travels for X, Y, Z, and W are 3,000, 2,000, 1,600, and 500 mm. Capable of handling loads weighing up to 15,000 kg and automatically adjusting for backlash, the 250C's rotary table features Daewoo's new double-pinion drive system with a Heidenhain rotary encoder at its center.

When it came to turning centers, DIMF gave visitors a sneak peek at what's new for 2004. These machines included the Puma Inverturn 300, Puma 240-2SP, Puma V400, Puma TT 2000, and Puma MX 2000.

The Inverturn 300 is an inverted vertical turning center with a traveling headstock and fixed turret. To provide loaderless automation, the machine's spindle moves on an X axis to a load area, picks up a workpiece, and takes it to the turret. This eliminates the need for part grippers, chucks, or jaws.

Various machine configurations are available, such as a milling version with 30-hp, 4,000-rpm spindle. Also, as an option, users can add a part conveyor.

Another new inverted turning center is the Puma V400. With a standard 304-mm chuck and 381-mm optional one, the machine cuts part diameters up to 500.38 mm and lengths to 459.7 mm. Axes ride on boxways, and there is an available mill-turn option.

Resting on a separated two-bed base, Daewoo's Puma 240-2SP is a turning center housing two spindles and a built-in gantry loader as an option. Available chuck sizes are 152.4, 203.2, and 254 mm, along with two gantry loader options for 150 or 210-mm-diameter work.

The Puma TT 2000, with an 203.2-mm chuck and 66.7-mmdiameter bar capacity, and its counterpart, the Puma TT 2500 with a 254-mm chuck and 76.2-mmdiameter bar capacity, both feature twin spindles and twin turrets. Both spindles and both turrets deliver equal capacity.

Because of their modular constructions, both these multifunction turning centers are configurable into different versions. They rest on 45° slant-bed bases with ground boxways and separate coolant tanks.

Upper turrets provide either turn, mill-turn, or mill-turn plus Y capabilities, while the lower turret does turn or turn-mill. Both the left and right spindles accommodate turn and mill-turning. These turret and spindle capabilities offer users various machining options, including simultaneous turning at both spindles; synchronized spindles for simultaneous turning of one part; simultaneous balanced turning; simultaneous O.D. and I.D. cutting; and pinch turning.

Like the Puma TT 2000 and TT 2500, Daewoo's Puma MX 2000 sports a 203.2-mm chuck, while its Puma MX 2500's is 254 mm. Both these multi-axis turning centers feature a milling spindle with B-axis rotary range of ±120°.

A 20-hp motor drives the 10,000-rpm spindle that uses flange-contact toolholding and lets users do Y-axis machining. In addition, the Y axis is a double-slide wedge type with a 160-mm (±80-mm) travel and a 630-ipm rapid.

Along with milling spindles, the MX 2000 has a 5,000-rpm left-side spindle, and the MX 2500 carries both left and right-side spindles with 3,500-rpm capability. In addition to twin spindles, the MX 2500 features a servo-indexed, 12-station lower turret. Also like the Puma TTs, the two MXs come in different versions because of their modular constructions.

As if its new HMCs, VMCs, and turning centers weren't enough, Daewoo showcased several concept machines at DIMF 2003. These included a linear-motor HMC, VMC, and mill/turn center.

The linear-motor HMC, called the FH 500, delivers a 2-G feed acceleration and sports a 35,000-rpm spindle. Its resinconcrete base dampens vibration and provides thermal stability for the machine's X, Y, and Z-axis travels measuring 630, 630, and 500 mm. Daewoo's linear-motor VMC, the FV 400, also accelerates at 2 G, features a 35,000-rpm spindle, and rests on a resin-concrete base.

On its linear-motor mill-turn center, the Puma 1500M, Daewoo equips a 6,000-rpm main spindle. The machine accelerates at 1 G and rapids as fast as 40 m/min. Its C-axis spindle indexes at 0.001° increments.

Stamping out die defects

NIST post doctoral research fellow Mark Iadicola examines a sample of sheetmetal tested with NIST's new formability-testing station.

RESEARCHERS AT THE NATIONAL Institute of Standards and Technology (NIST) want to eliminate defects in dies used to make sheetmetal parts. Their work could yield impressive cost savings — particularly for the automotive industry, which spends an estimated $700 million a year on designing, testing, and correcting new dies for its latest models. About half of the total cost goes for remedying unanticipated errors manifested as wrinkles, splits, excessive thinning, or other defects.

Using NIST's one-of-a-kind test equipment, which fits together a metal-stamping test station with an X-ray stress-measurement system, researchers make detailed maps of stresses and strains as sheets of steel and other metals are punched, stretched, or otherwise shaped to achieve the desired part geometry. According to project leader Tim Foecke, the system measures stress and strain behavior in many different directions while the sheet is stretched in two directions simultaneously, a condition most commonly seen in forming operations.

Current methods extrapolate from strain-measurement testing that stretches sheets in only one direction. As a consequence, newly designed dies often undergo successive rounds of refinement to correct for these simplifications in computer models.

U.S. automakers and producers of steel, aluminum, and other metals, including developmental ones, are supplying Foecke's team with samples for testing and evaluation. The aim of the project is to build a database of material properties that designers can feed into computer models for predicting whether would-be dies can form particular metals into specified shapes, within tolerances. Project findings might point the way to new metalforming methods, according to NIST.

Bond-and-release epoxy aims to shock

ElectRelease high-strength epoxy is sandwiched between metal substrates.

Applying between 10 and 50 V of electricity causes the epoxy to disbond, cleaving the "sandwich" into two pieces — one clean substrate and another with the epoxy still attached.

SHOPS MAY SOON DITCH CLUMSY fasteners and replace them with a new high-strength, electrically disbonding adhesive called ElectRelease. The epoxy bonds together metal substrates and withstands shear forces to 2,000 psi. Users simply apply 10 to 50 V of electricity to the bonded joint to separate the parts into one clean substrate and another with the epoxy still attached.

EIC Laboratories Inc. of Norwood, Mass., which developed ElectRelease, says that industries such as automotive, industrial equipment, and aerospace could use the epoxy in a number of applications — such as bonding fenders to automobiles or attaching temporary structures to aircraft (rather than drilling bolt holes in a wing or fuselage). The technology also holds promise for use in space, where it could replace the explosive mechanism often used to detach the components of a spacecraft or satellite. A major application involves holding workpieces steady for machining. Parts are easily separated once milling, turning, grinding, or other operations are complete.

Users of the low-voltage release mechanism need only a thin, light layer of the epoxy, offering a weight advantage over heavy conventional fasteners such as metal bolts.

To make the epoxy, users mix two separate chemicals, which come in a two-barrel tube that meters out the proper proportions. At room temperature, the mixed epoxy has a working life of 40 min, and it fully hardens in 24 hr. At elevated temperatures (approximately 175° F) hardening takes just an hour.

According to Dr. Stuart Cogan, EIC's vice president of advanced materials, EIC anticipates commercial opportunities for the technology throughout the Department of Defense and NASA as well as in private-sector launch vehicles and satellites. He says the company is continuing to refine its product and seek new markets and appropriate applications. "We would like to see a considerably shortened cure time for these epoxies so that they would be much more amenable to a high-volume manufacturing operation," says Cogan. He adds that once these refinements are made, it shouldn't be difficult to find a contractor to produce epoxies in large batches.

ElectRelease has been released as a commercial product, and Cogan expects to have a marketable, rapidcuring product within the next one to three years, at which time licensing of the technology will be a strong option.

Definitely not run-of-the-mill materials

A button of yttrium-silver shows dents and deformations from repeated hammer blows. On the left are pieces of a brittle gadolinium-silicon-germanium intermetallic alloy that was shattered with just a light tap.

(Photo courtesy of the Department of Energy's Ames Laboratory.)

WHILE INTERMETALLIC MATERIALS (compounds consisting of two or more metals bonded together) are often superior to ordinary metals in terms of chemical, physical, electrical, magnetic, and mechanical properties, they're typically quite brittle. However, a discovery by researchers at the U.S. Department of Energy's Ames Laboratory at Iowa State University promises to open up new possibilities for these materials.

A research team led by senior metallurgist Karl Gschneidner Jr. and materials scientist Alan Russell has identified 12 rare-earth intermetallic compounds that are ductile at room temperature. "Many intermetallic materials are too brittle to handle," says Gschneidner. "If you drop them, they shatter. But you can beat on these new materials with a hammer, and they won't shatter or fracture — they're that ductile."

Such materials could be used to produce practical materials from coatings that are highly resistant to corrosion or that maintain strength at high temperatures to flexible superconducting wires and extremely powerful magnets. There may also be other applications for these ductile materials because of their high-temperature strength and/or corrosion resistance.

Research thus far has focused on yttrium-silver (YAg), yttriumcopper, and dysprosium-copper. However, a preliminary examination of other rare-earth compounds shows that ceriumsilver, erbium-silver, erbium-gold, erbium-copper, erbium-iridium, holmium-copper, neodymium-silver, yttrium-indium, and yttriumrhodium are also ductile.

In tensile-strength testing, these materials showed remarkable ductility. The YAg stretched nearly 25% before it fractured, compared to 2% or less for many other intermetallics. In other measurements, the materials showed American Society for Testing and Materials fracture toughness values (KIC) comparable with commercial aircraft-aluminum alloys.

Cable-free molding lightens the load

Compared to an aluminum part with traditional wire harness (left), SpaceWorks' multifunctional part is about 57% lighter and flexible enough to accommodate component mounting.

A TECHNIQUE TO INTEGRATE FEATURES into compression-molded components could someday create "cable-free" structures for spacecraft, consumer electronics, industrial machinery, and automobiles. The compressionmolding process fashions lightweight composite components — with masses roughly 60% of their aluminum counterparts — in a much faster timeframe than conventional metalworking methods such as casting, stamping, machining, and welding.

SpaceWorks Inc., a Carefree, Ariz.-based firm funded by the Missile Defense Agency, is currently focusing on the design, fabrication, and qualification of a full-scale, flight-quality, multifunctional spacecraft. Designers are currently embedding subcomponents such as wire harnesses, flex circuits, radiation shielding, or thermalconductivity inserts (heat pipes) within molded parts.

While today's space-system manufacturing uses aluminum structures and electronics enclosures, compression molding appears to have cost and time-saving benefits when applied to mass production. The process also eliminates the need for some fasteners, simplifying assembly and further minimizing mass.

According to SpaceWorks, an organization making at least 10 to 20 parts with composites and a mold will spend less money than if it manufactured the same number of parts from aluminum. Another benefit is once a mold is made, shops can use it repeatedly — generating a custom component in as little as an hour. Molding also helps shops go beyond the straight-line geometrical configurations typically used in spacecraft.

SpaceWorks has delivered electronics enclosures for sensors to NASA's Jet Propulsion Laboratory and the Air Force Research Lab. The company is also identifying new markets for the technology.

Man and machine get on the same page

AS ELECTRONIC DEVICES BECOME more complex, user interfaces must become easier to understand and use, according to Jeffrey M. Gerth, a senior research scientist at the Georgia Tech Research Institute. He is currently developing interfaces to help operators better handle and troubleshoot production jobs.

"The job of operators is to monitor machines so they're in constant operation," says Gerth. "If production stops or isn't going as fast as intended, then a manufacturer is losing money."

Gerth's latest project involves DEK, an international machine manufacturer headquartered in Weymouth, England. He has improved the user interface on screen printers that DEK produces for the circuit-board and electronicsassembly industries.

The redesigned interface, dubbed Instinctiv, is reportedly easier to use than DEK's previous text-based interface. Its graphic display reduces language dependency, which is important for an international player like DEK. Instinctiv also helps operators take independent and appropriate action rather than call on process engineers.

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