Metalcutting: Multitasking Equipment
The evolution continues
Multitasking machines probably make up the most dynamic segment of the machine-tool industry. Still a small portion of overall machine sales, multitasking technology is gaining in importance as more users realize the benefits of single-setup machining of complex parts and as builders make the machines easier to use and more capable.Over the past few years, machines have evolved from essentially turning centers with some milling capability (or, conversely, machining centers with a rotary table that enabled some basic turning operations). Offerings now include unique machine configurations that combine processes ranging from turning and milling to grinding, honing, hobbing, inspection, assembly, welding, and others.And, as machine variations have multiplied, builders are refining their marketing pitches to reflect the differences among their products. Some are even redefining terms--or coining new ones--to describe the technology.
"Multitasking implies performing multiple operations on a part simultaneously, for example, screw machining or multiple spindles," says David Austin of Mori Seiki (Irving, TX). "We prefer the term 'integrated machining,' which refers to operating on a part with one process at a time, sequentially, within the same machine."
At Mazak Corp. (Florence, KY), VP Chuck Birkle talks about ultratasking--integration of a wider variety of processes into a single machine platform. "Customers are increasingly accepting the multitasking concept, and they are also looking to move beyond milling, drilling, and tapping and add hobbing, polishing, and grinding to the workpiece while it is in the machine," he says. "We certainly see an increasing movement into such ultratasking."
The term "multitasking" should be replaced with "multi-application" to describe the capabilities of the current crop of machines, according to David Barber of United Grinding Technologies (UGT; Miamisburg, OH).
"Multitasking equipment is evolving into 'multi-application,'" he says. "In the not-too-distant past, we could say that a grinder with both OD and ID grinding capabilities was multitasking. Today, these types of grinders are almost common. The same may be true in the chipmaking world when it comes to turning centers with milling capabilities."
Barber points out that use of multitasking equipment can support lean manufacturing initiatives. "By setting up a machine once for several operations, we see the reductions that define lean: less material handling as the workpiece remains in one machine for multiple operations, less setup as the machine is placed in one flexible fixture."
At IMTS, UGT will demonstrate the Schaudt Stratos, which can hard turn, mill, and grind a part in one clamping. The machine features an inverted vertical spindle that picks up a part from a built-in conveyor system. The part is then hard turned and machined in one chamber using an eight-station indexing turret with live tooling. The part is then transferred to a second chamber for ID and OD grinding.
Whatever you call it-- integrated machining, ultratasking, multi-application, or multitasking--the technology's main goal is clear, according to Birkle: "The idea is to incorporate as many functions as possible in fewer setups to reduce tooling and fixture costs. Rarely does a company invest in multitasking equipment to produce parts in a traditional fashion. Instead, through solid modeling and more powerful toolpath-verification software, parts and components can be produced on multitasking equipment in fewer pieces."
Mazak is strengthening its relationships with developers of CAD/CAM, NC verification, and other types of software in an effort to create a "virtual machining" environment that accelerates both part and process development, Birkle adds.
IMTS visitors will see Mazak's Integrex 400-IIIST, the third generation in the company's multitasking line. The two-spindle machine features 3300-rpm maximum turning spindle speed and 12,000-rpm maximum milling spindle speed, with 12" (305-mm) chucks on both spindles. The upper turret has an automatic toolchanger and 20-tool magazine, while the lower turret is a nine-position drum. Linear guides on the X, Y, and Z axes allow rapid-traverse speeds of 1496, 1024, and 1496 ipm (38, 26, and 38 m/min), respectively. A roller gear cam mechanism on the B axis is said to achieve positioning in 0.0001º increments.
Gaining "done in one" capability may be the main enticement for manufacturers to switch to multitasking equipment, but there are several other benefits as well.
Lucien Marini of DMG America (Schaumburg, IL) points out that space is a valuable commodity on most shop floors these days. "Floor space is hard to come by, so companies are looking for machines to do complete machining on one platform," he says.
Visitors to DMG's IMTS exhibit will see machines from the GMX line of multitaskers. An example is the GMX 400 linear, a modular machine that can be configured with everything from an NC tailstock to a counter spindle, 12-station CNC turret with driven tools, and B axis with a swiveling range of ±120º and a 12,000-rpm spindle. Control is via a Siemens 840 D Powerline CNC.
Gary Hulihan, VP of EMAG (Farmington Hills, MI) says improved quality is also important to users of his company's equipment. "The bar for quality is continuing to be raised, and our customers must compete in a business that demands parts faster, better, and at lower cost. Quality is improved by limiting setups and transfers between machines," he says.
EMAG claims to have originated the current multitasking concept with the 1998 introduction of a machine that performed both turning and grinding. Since then the company has used its modular machine platform to deliver equipment capable of integrating assembly, laser welding, and measurement with machining and grinding operations.
The bottom line with multitasking, Mori's Austin believes, is the bottom line. "By far the most significant trend in the US economy is the growth of productivity," he explains. "A three-axis vertical machining center and a two-axis lathe increase productivity only marginally by delivering faster cycle times. However, there is no fundamental shift in the process--the increase in productivity equals the improvement in cycle time.
"Companies that can successfully raise quality, cost, and delivery at the same time are the ones truly improving. Multitasking machining technology is becoming popular because it can help manufacturers do just that," he concludes.
Visitors to Mori's IMTS exhibit will see machines representing several lines of mulitasking equipment. These include ZT and MT-series machines, as well as the SuperMiller 400. The latter features a tilt/rotary table that provides five-axis machining center capability as well as turning to 1500 rpm on the A axis. The tilting B axis moves vertically over a range of -20 to +110º using a roller gear drive. Other features include a 12,000-rpm, BT40 spindle and 30-tool ATC. Travels are 600, 425, and 450 mm in X, Y, and Z axes, respectively.
The company has also implemented an expanded support program for its multitasking machines. The 5-5-5 program includes five days of on-site training, five days of training at Mori Seiki, and five days of training to use at the customer's discretion.
Following is a listing of multitasking machines scheduled for display at IMTS.
Over the past few years, machines have evolved from essentially turning centers with some milling capability (or, conversely, machining centers with a rotary table that enabled some basic turning operations). Offerings now include unique machine configurations that combine processes ranging from turning and milling to grinding, honing, hobbing, inspection, assembly, welding, and others.And, as machine variations have multiplied, builders are refining their marketing pitches to reflect the differences among their products. Some are even redefining terms--or coining new ones--to describe the technology.
Five-Axis Turning and Milling
Model VTM-80YB from Okuma & Howa offers X -axis travel of 1120 mm, Y-axis travel of ±355 mm, and Z-axis travel of 1135 mm. Pivoting-spindle B-axis combined with the rotating C-axis can accomplish indexing five-axis machining for complex parts and offer reduced setup time and single chucking simplicity. A 15-kW tool spindle drive and a 22-kW work spindle provide power for machining in new alloys or exotic materials. A 36-tool magazine is standard.
KGK International Corp.
Five-Axis Mill-Turn Center
The H5-1000MT five-axis mill/turn HMC is designed to machine parts 50" (1270 mm) in diam and larger, by combining four and five-axis machining with high-speed turning capabilities. It features a direct-drive rotary table available in high-torque (300 rpm) or high-speed (700 rpm) configurations. An A-axis tilt spindle provides 180º sweep for five-side cutting, and spindles come in high-torque or high-speed models ranging from 6000 to 24,000 rpm. Machine offers palletized material handling with a choice of 1 X 1-m square, 1 X 1.25-m rectangular, or round pallets, and is cell ready.
Flexible Multitasking Centers
Configured with one or two spindles, C axis, live tools, and a Y axis, the slant-bed E 280 features: swing of 25.6" (650 mm), maximum cutting length of 15.75" (400 mm), cutting diam of 11.02" (280 mm), and distance between spindle faces of 30.71" (780 mm). Left and right spindles feature 15 or 25 hp (11 or 18.6 kW) motors with variable-speed drives (speeds range from 4 to 6000 rpm). Tailstock is fully programmable. Turret options are T for standard turning tools, M for live tools, and MY for live tools combined with a Y-axis assembly.
Romi Machine Tools
The new Integrex 400-IIIST eliminates work-in-process and reduces throughput time by allowing completion of parts in one setup, driving significant reductions in setup time, fixturing, and tooling while improving dimensional quality. The company's third-generation multitasker is a two-spindle machine with a 3300-rpm turning spindle and 12,000-rpm milling spindle, each with a 12" (305-mm) chuck. The main headstock has an integral spindle/motor that allows heavy-duty metalcutting. Automatic tool-change time of 1.3 sec tool-to-tool is said to be the fastest in its class. Other features include linear guides on the X, Y, and Z axes and a roller gear cam mechanism on the B axis that achieves positioning in 0.0001º increments. The Mazatrol Fusion 640 MT Pro CNC control provides fast execution and programming.
Company produces several series of multitasking machine tools, including ZT series turning machines with dual independent spindles and turrets, MT multiaxis turning machines with milling capability, and new NL series lathes with a direct-coupled milling motor and rigid toolholder said to allow milling capability rivaling that of 40-taper machining centers. Visitors to IMTS will also see the SuperMiller 400, featuring a tilt/rotary table that provides five-axis machining capability as well as turning to 1500 rpm on the A axis. The machine's tilting B axis moves vertically over a range of -20 to +110º using a roller gear drive. A 12,000-rpm, BT40 spindle and 30-tool ATC are standard, and the machine has primary axis travels of 600, 425, and 450 mm in X, Y, and Z, respectively.
Mori Seiki USA Inc.
Two Spindles, Four Turrets
With twin spindles and up to four, 24-station turrets that can accommodate as many as 48 live tools, Nakamura turning centers perform turning, milling, and boring in a single setup without operator handling, additional setup or breakdown, or work-in-process. A Fanuc CNC facilitates right and left-side programming, and allows each spindle to be run separately. Users can select machines with two to 12 axes under control and chuck sizes from 6 to 12" (152 - 305 mm). Available options include tool probes, part probes, and bar feeders.
Methods Machine Tools Inc.
Company uses robust modular platforms to produce multitasking machines capable of turning, drilling, tapping, milling, boring, reaming, grinding, polishing, broaching, marking, welding, hardening, and other operations, and claims to have delivered more than 4500 machines worldwide. An example is the HVSC 400 MT vertical/horizontal turning and machining center, which offers five-side complete machining of complex parts using turning, drilling, milling, and grinding operations. Visitors to IMTS will see the company's latest offering, the BAS-03 machine.
This article was first published in the August 2004 edition of Manufacturing Engineering magazine.