FEBRUARY 2007 / VOLUME 59 / NUMBER 2

➤ BY Joseph L. H a z e lton, senior editor Multienhancing Multitasking machine , like this mill/ turn center, can reduce setups, shorten handling time and increase accuracy by allowing for complete within one enclosure.

Mill/turn centers, the most com- advantages: fewer setups, reduced mon type of multitasking machine handling time and greater part Machine tool, appear to be the ultimate in accuracy. builders continue process consolidation. Inside its Everything has limitations, enclosure, a mill/turn center can though, and there are trade-offs to improve perform many of the functions with multitasking machine tools. A the capabilities of a 5-axis horizontal machining mill/turn center provides the ben- center—, , , efit of process optimization, but its of mill/turn centers. tapping—as well as , once various operations may not be as limited to . fast as they would be on separate That consolidation offers several machine tools. So the cycle time Doosan Infracore Doosan Infracore for a part produced in a mill/turn based multitasking machine tools ture includes twin ballscrew drives center can be longer than the sum could be described as 70 percent for both the X and Z and thereby of the cycle times if the part were turning machines and 30 percent permits driving at the center of grav- produced on separate milling and milling machines, according to Gerald ity. Mori Seiki refers to the design as turning centers. Owen, national applications manager DCG (Driven at the Center of Grav- That longer time, however, is usu- for builder Mori Seiki ity). ally recouped through a shorter setup USA Inc., Rolling Meadows, Ill. Another recent, significant im- time than the sum of the setup times Today, though, there are mill/turn provement was a longer Y-axis travel on the separate machines. As a limi- centers designed to mill on par with for the NT series. Previously, regard- tation, the possibility of slower ma- conventional machining centers and less of the , mill/ chining may someday be entirely turn on par with conventional lathes. turn centers often had long X-axis eliminated through improvements to Among those mill/turn centers are the travels, but limited Y-axis travels for mill/turn centers and other multi- Integrex Mark IV series from Mazak the tool spindles. For example, the MT tasking machines. Corp., Florence, Ky., and the NT series series had models with X-axis travels However, mill/turn centers have from Mori Seiki. To accomplish this, of 635mm and 1,008mm, but their Y- been improved in several ways in Mori Seiki transferred several subas- axis travels were 220mm and 300mm, recent years. semblies from its NL lathes and NH respectively. Today, the newer NT4000 machining centers to its NT mill/turn series of machine tools have X- and Fully Functional Milling centers, its latest series of multitask- Y-axis travels of 750mm and 420mm, and Turning ing machine tools. respectively. Compared with milling machines “We did not allow any lessening of “We have X- and Y-axis travels and lathes, one limitation of mill/ performance,” Owen said. more like what would be expected turn centers was the loss of some The subassemblies included in a machining center,” said Greg milling or turning capabilities. the headstocks and lower turret with Hyatt, a Mori Seiki vice president. In the past, mill/turn centers were integral, driven tools. The machining Hyatt is the chief technical officer for only somewhat capable in their mill- center’s subassemblies consisted of the company’s Machining Technology ing or their turning. Previous lathe- its spindles and structure. The struc- Laboratory, also in Rolling Meadows.

A multitasking machine for a narrow application

ill/turn centers can perform a Afterward, the carrier is moved to a Mrange of machining operations. grinder to finish to final tolerances After all, the machine tools can be built the bores’ sizes and locations. The final to mill, turn, bore, and grind to tolerance level can be very tight. name just some of the possible opera- “Most often, it’s 10 microns or bet- tions. But, depending on its design, a ter,” Dolan said. center’s actual use can be narrow, as in However, Mitsui Seiki reduced the the case of the VU65A-SP. number of machine tools and opera- Mitsui Seiki built that mill/turn cen- tions involved in the previously men- ter for the production of carriers, tioned processing by applying its jig- mainly planetary gear carriers. The ma- boring and jig-grinding knowledge to

chine tool builder created the VU65A- Mitsui Seiki a mill/turn center. The result was a SP to reduce the number of machine A high-precision mill/turn center turns vertically oriented center with a spin the face of a mild-steel workpiece, tools needed to turn, mill, bore and table. The table gives the center its which became part of an inspection otherwise machine the carriers. gage inside another machine tool. The turning capability. Tom Dolan, Mitsui Seiki’s marketing mill/turn center’s design is based on Given its jig work, the VU65A-SP is manager, described a conventional way jig machine tools, so it can perform built for high precision. The center has of machining a planetary gear carrier. precision work often done on jig a positioning accuracy of 2 microns or borers and jig grinders. The machine The machining starts with a lathe, better, and its typical turning accuracy also performed off-center precision which rough- and finish-turns the boring and milling on the workpiece. is 2-microns roundness or better. carrier’s diameters, including the car- Thus, three machine tools were re- rier diameter that will align with the tapping and rough and semifinish bor- placed by one for producing the plan- mounting diameter of the carrier’s cen- ing. The bores include those that will etary gear carrier. “We’ve been able to tral gear, the sun gear. The workpiece is align the location diameters of the achieve all the required tolerances on then transferred to a machining center carrier’s planetary , which sur- one machine tool,” Dolan said. for rough and finish milling, drilling, round the sun gear. —J. Hazelton for a part produced in a mill/turn center could be described Integrex multitasking centers by incor- ory for a 2MB program, and optional can be longer than the sum of the cycle as 70 percent turn- porating a lower turret so The ‘Brains’ of Mill/Turn Centers memory for an 8MB program. Also, the times if the part were produced on ing machines and can be machined simultaneously by Several improvements have cen- previous generation system could store separate milling and turning centers. 30 percent mill- both the upper and lower turrets. The tered on the controls and software of 500 sets of tool offsets and accommo- That longer time, however, is usually ing machines, ac- lower turret accommodates milling mill/turn centers. date tool data registration for up to 1,000 recouped through a shorter setup time cording to Gerald and turning tools. In Integrex IV mod- A multitasking machine tool requires tools. The Matrix can store 4,000 sets of than the sum of the setup times on the Owen, national ap- els, the lower turret can hold up to nine a lot of computing power to control the offsets and accommodate registration separate machines. As a limitation, the plications manager tools or serve as a steady rest or center simultaneous movement of its many for a maximum of 4,000 tools. possibility of slower machining may for machine tool to enhance machining. axes. For example, a Mori Seiki NT Software was a main concern in

someday be entirely eliminated through builder Mori Seiki Mori Seiki The newly introduced Integrex e- mill/turn center has the option of being 2006 for machine tool builder Doo- Consolidating turning and milling in one machine tool once improvements to mill/turn centers and USA Inc., Rolling involved noticeable compromising of one or both processes. 420H-ST II has a lower turret for ro- equipped with two headstocks, allow- san Infracore America Corp., West other multitasking machines. Meadows, Ill. But many mill/turn centers are designed today to be fully tary tools with X-, Y- and Z-axis travel ing it to function as a 5-axis VMC at Caldwell, N.J. The company spent However, mill/turn centers have Today, though, functional in their milling and turning. capacity. Its has a maximum one end of its enclosure and as a 3-axis time improving programs to speed been improved in several ways in re- there are mill/turn speed of 6,000 rpm. Also, the lower lathe at the other end. throughput of its mill/turn centers, the cent years. centers designed to mill on par with con- machine tool builder, mill/turn cen- turrets can be equipped with special Given all those axes, there’s a greater Lynx and Puma series. ventional machining centers and turn on ters often had long X-axis travels, but adapters to serve as steady rests or chance of interference—of tools crash- Doosan Infracore’s efforts are pay- Fully Functional Milling par with conventional lathes. Among limited Y-axis travels for the tool spin- centers for supporting shafts. ing into workpieces. Consequently, ing off. Bob Appleton, multitasking and Turning those mill/turn centers are the Integrex dles. For example, the MT series had each NT mill/turn center can check applications engineer, said time was Compared with milling machines Mark IV series from Mazak Corp., Flor- models with X-axis travels of 635mm The following companies for interference via a front-end control saved in machining aspects like chip- and lathes, one limitation of mill/turn ence, Ky., and the NT series from Mori and 1,008mm, but their Y-axis travels contributed­ to this report: that includes a 1.6GB dual processor. to-chip time, which was reduced from centers was the loss of some milling or Seiki. To accomplish this, Mori Seiki were 220mm and 300mm, respectively. As a front-end control, it doesn’t take 16.5 seconds to 9 seconds for the ma- turning capabilities. transferred several subassemblies from Today, the newer NT4000 series of ma- Doosan Infracore America Corp. any computing power from the ma- chine tools in the company’s Puma In the past, mill/turn centers were its NL lathes and NH machining centers chine tools have X- and Y-axis travels (973) 618-2500 chine tool’s CNC system. MX series. Each of those machine only somewhat capable in their mill- to its NT mill/turn centers, its latest se- of 750mm and 420mm, respectively. www.infracoremt.com Similarly, Mazak’s Integrex series tools has a 40-tool capacity, with the ing or their turning. Previous lathe- ries of multitasking machine tools. “We have X- and Y-axis travels more includes a 64-bit, twin-engine proces- option for an 80-tool capacity. based multitasking machine tools “We did not allow any lessening of like what would be expected in a ma- Mazak Corp. sor for faster calculations. The pro- Also, Doosan Infracore achieved performance,” Owen said. chining center,” said Greg Hyatt, a Mori (859) 342-1700 cessor is part of the company’s latest those time savings without changing The lathe subassemblies included Seiki vice president. Hyatt is the chief www.mazakusa.com CNC, a sixth generation system called the designs of its multitasking machine the headstocks and lower turret with technical officer for the company’s the Mazatrol Matrix. The new CNC tools. integral, driven tools. The machining Machining Technology Laboratory, Mitsui Seiki (U.S.A.) Inc. results in a more productive multitask- “Mechanically, not a change at center’s subassemblies consisted of also in Rolling Meadows. (201) 337-1300 ing machine tool. all,” Appleton said. “It’s all machine its spindles and structure. The struc- Hyatt added that the longer Y-axis www.mitsuiseiki.com “When you cut the parts, you can logic.” ture includes twin ballscrew drives travel was possible because of the ram really tell the difference in accuracy Doosan Infracore’s improved pro- for both the X and Z axes and thereby design. Octagonally shaped, the ram Mori Seiki USA Inc. and cycle time,” said George Yamane, grams are available for new instal- permits driving at the center of gravity. has an opposing side length of 400mm, (847) 593-5400 Mazak’s marketing manager. lations and as upgrades for current

Mazak Mori Seiki refers to the design as DCG so the center of gravity doesn’t extend www.moriseiki.com memory has been upgrad- installations. A multitasking machine tool processes (Driven at the Center of Gravity). over the supported section. The design ed, too. The Matrix system has mem- a cylindrical bar, machining it into a Another recent, significant improve- allows the ram to remain rigid and per- turbine . Recent improvements to multitasking machine tools have ment was a longer Y-axis travel for the mits the longer travel. included direct-driven assemblies and NT series. Previously, regardless of the Mazak improved a number of its TOOL Magazine is protected under U.S. and international copyright laws. upgraded controls and memory. Before reproducing anything from this Web site, call the Copyright Clearance Center Inc. at (978) 750-8400.