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A View on Advancing Metalcutting Technology

As vp of Technology at AMT, Paul Warndorf is keeping tabs on what's going on in both the commercial and academic worlds when it comes to material processing. Here's some of the things he's seen of late.

As he's anticipating the 2006 International Manufacturing Technology Show (IMTS), Paul Warndorf, vice president-Technology, AMT—The Association For Manufacturing Technology (www.amtonline.org), the organization that puts on IMTS, says that one of the key trends he sees in metalcutting technology is "precision." Precision in at least a couple of ways:

1. "Precision in the way they have designed the machines." Warndorf explains that one of the things that has been going on in the machine tool industry of late is that there is an increased use of computer-aided engineering in order to assure that the machines are built in such a way so that they can meet production requirements more precisely. Whereas machine tools were once built as rather monumental structures, they are now, generally, based on a leaner concept.

2. Precision in the performance of the machines: "It's something that people strive for every year," Warndorf says, adding that going forward this is likely to be an even-greater characteristic, especially as the machine builders face new competitors from China.

In either case, it is a win for the customer of the machine tool.

SMALL. There is another area of precision that Warndorf sees emerging in metalcutting and processing. This is the area of "small machines," machines that are in the realm of "micromachines." Warndorf says that heretofore, "You have to buy a pretty large machine"—which he says might measure 5 x 3 ft., which means that "pretty large" is a relative term—"to produce these small parts." The parts he's talking about range in size from approximately that of a pin head to 0.125 in.2. Now there is a move toward producing machines that themselves are 1 x 1 ft.—desktop machines, in effect. What's more, there is research and development under way in what he calls "microfactories." Presumably, one could build an entire factory in a space about the size of a desk or conference table, given the small size of the machines. Because they're interested in seeing this sort of development advance, there is an "Emerging Technology Center Pavilion" at IMTS, where there are a number of universities, research groups, and companies displaying microdevelopments, including those for metalcutting.

BIG. Precision is something that, Warndorf says, is being driven by changing requirements in industries. He points out, for example, that the Joint Strike Fighter (JSF) program has reduced the tolerances on parts to the extent that "the manufacturers, the sub-tiers, are having a challenge to produce those parts. In the aerospace world you're going to see a change to tighter-tolerance parts, which will then raise the issue of the precision of machine to be highlighted even more." To be sure, if you're making exceedingly small parts it is necessary to have tight tolerance, but Warndorf points out that in the case of the JSF they're talking about large parts, too.Presumably, if there are these precision demands in aero, it is simply a matter of time until they reach auto.

SMART. This discussion of the sub-tiers doing more of the actual parts manufacturing leads to an issue that Warndorf describes as being challenging, especially as people start trying to achieve what he calls "first-part correct." That is, how can a manufacturer make a complex, tight-tolerance part right the first time, especially if that manufacturer is at a second or third tier and doesn't necessarily have access to all manner of advanced technology? Right now, it probably can't. So AMT is working with several other organizations in the Coalition on Manufacturing Technology Infrastructure (CMTI), and one of the programs that is being undertaken by the coalition is called the "Smart Machine Platform Initiative" (SMPI). It has received its initial funding, $2-million, through the U.S. Department of Defense.

Speaking of the type of capability that they would like to have for the SMPI—and Warndorf emphasizes that the undertaking is not about a machine design, per se, as it is about the performance and functionality of the machine—he references work that was done by the late Professor Jiri Tlusty of the University of Florida. Tlusty found that there is a "sweet spot" in machining that is found when there is the right correlation with the depth of cut, spindle speed, tool geometry, etc. Warndorf says that presently, it is necessary to assemble the tool, but the cutter in the holder, then use a measuring device to determine the frequencies of the cut such that the "sweet spot" can be determined. This is the sort of thing that the aforementioned second- or third-tier supplier (and to be fair, OEMs and tier ones) might not be likely to do. "We're looking at how we could automate that," Warndorf says. But this isn't automating it from the point of view of going through the mechanical sequences, achieving the results, then dialing in the machine. Rather, he explains, what they're hoping to come up with is a means by which when the machine control receives the program for a particular part it is able to make the determination of given the required outcome and the specific parameters (e.g., the tooling, machine capability, part to be produced), it could make a recommendation that there be a modification to the program (e.g., to back off on the federate) so as to get to the "sweet spot." Given that, Warndorf says, "It would increase the first-part-correct confidence level."

Of course, achieving this is no mean feat, nor is it something that is going to be achieved inexpensively, so the CMTI members are looking at other research programs that are being conducted so as to determine if and where there could be some benefits for SMPI.

"What we're trying to push in the Smart Machine," he says, "is making all of this capability available to the user, but the user doesn't even know he's using it. The customer doesn't have to program the capability—the feature is used automatically." 

 

Compact Turning Machine

The NZ-S1500 from Mori Seiki (www.moriseiki.com) is said to have been developed with an automaker, so it is designed to deal with industry demands. It is a compact machine, with a footprint of just 29.1-ft2, yet it is a capable unit that has a maximum turning diameter of 4.7 in. and maximum turning length of 21 in. It has a twin-turret configuration, with the turrets aligned with the spindle, which is mounted on the vertical bed, thus facilitating chip disposal, and which minimizes heat effects during production operations. As the machine is just 59.1-in. high, it provides easy sightlines for lean production operations.

 

Twin-Turret Turning

The Daewoo PUMA TL-series of high-performance turning centers available from Doosan Infracore America (http://usa.doosaninfracore.co.kr), the TL2000 and TL2500 are designed for heavy cutting, as the spindle is driven by either a 30-hp or 35-hp integral motor. The TL2000 can handle parts 9.4-in. in diameter and up to 23.6 in. long, or 2.6-in. diameter barstock. The TL2500 can handle parts up to 39.3-in. long or 3-in. barstock. The top turret handles 12 tools and the lower eight; live tooling can be deployed at any station. Indexing time is just 0.10 sec.

 

Cast Iron Mill

The CoroMill 365 from Sandvik Coromant (www.coromant.sandvik.com/us) is designed for high-volume production operations or where large quantities of cast iron are to be quickly removed, such as roughing on engine blocks or heads; it can also be used for finishing. There are eight right- or left-hand cutting edges with a thickness of 0.223 in. The cast iron insert grade is 1020; there are 1030 inserts for steel milling. The inserts can be used for wet or dry operations. The standard diameters range from 2 to 6 in.

 

Mill With Tangentially Held Inserts

The inserts have a butterfly shape and they're tangentially mounted and screw clamped in place into the milling cutter that's known as the Tangmill and are available from Iscar (www.iscarmetals.com). The shape and the mounting results in positive axial cutting angles and good chip control. The LNKX inserts offer eight cutting edges (four left-hand; four right-hand). There are face mills available in 45°, 75° and 90° types. One application they're said to be well suited to handle: engine blocks.

 

HMCs for Machine Shops

The EC-630 is a horizontal machining center with a 630-mm pallet (and associated changer) that offers X, Y, Z travels of 40 x 32 x 35 in., respectively. It features a 30-hp tapered geared head, and a 50-tool changer. The EC-400PP is a 400-mm pallet machine with a six-pallet pool and changer. As the scheduling and control are via machine control, lights-out production can be readily programmed. Features a standard 8,000-rpm, 40-hp, 20-hp spindle with a 40-taper spindle. Both machines are available from Haas Automation (www.haascnc.com).

 

Optimizing the Other Elements

Because getting parts to the spindle and having the right tools available to do the cutting are key aspects of productive metal removal for horizontal machining centers, Toyota Machinery USA (www.toyodausa.com) has developed the Flexible Pallet Automation (FPA) system and the Matrix Tool Magazine. The former features a modular so that not only can there be up to three levels of in-line pallet buffer racks, but different pallet sizes can be used within the system. The Matrix Tool Magazine can accommodate up to 500 tools up to 21.6-in. long and 9.84-in. diameter.