New tools for old on show in Chicago

New tools for old on show in Chicago

technical trends New tools for old on show in Chicago Ken Brookes went to one of the world’s biggest machine tool shows in Chicago and heard echoes f...

675KB Sizes 33 Downloads 66 Views

technical trends

New tools for old on show in Chicago Ken Brookes went to one of the world’s biggest machine tool shows in Chicago and heard echoes from history while rubbing shoulders with the innovative and the very rich...

L

ooking for hard materials developments in giant machinetool exhibitions – and they don’t come much bigger than Chicago’s International Manufacturing Technology Show – one feels a little like a Victorian at the close of the 19th Century. In those days they very nearly closed down the Patent Office in London, because “everything capable of being invented had already been invented.” Luckily the exhibitors’ booths in the increasingly vast caverns of Chicago’s McCormick Center housed more than the usual eager salesmen and piles of catalogues. There were some genuinely interesting items for those willing to dig deeply enough. Among those was a meeting with Warren Buffett, allegedly (after Bill Gates) the second-richest man in the world. By the simple process of buying 80 per cent of the Israeli Iscar organisation for $4 billion, Mr Buffett has instantly become one of the key individuals in the international hardmetal industry. No wonder he put a consoling arm around my shoulder. I know where I went wrong!

Figure 2. Zhuzhou production line for highprecision indexable inserts.

30

MPR November 2006

Figure 1. Sandvik Coromant GC1020 and GC3220 inserts for cast iron machining, in contrasting colours. Each corner is dot-numbered for identification.

One of the oldest and most distinguished names in the hardmetals industry took its final bow just prior to the show, though for legal purposes it was timed to happen after the exhibition closed (probably on 1 January 2007). The Carboloy Products Department of US General Electric (USGE) was one of the longest-established hardmetal producers in the world. Krupp-Widia was born in Germany in 1926, to commercialise Karl Schröter’s famous invention, and USGE secured the first US licence just two years later. It thrived for many years, but eventually succumbed to competition from more dedicated producers, coupled with poor top-level management and a lack of investment. It was finally sold to Sweden’s Sandvik/Seco enterprise in 1987, preserving the original name as “Seco-Carboloy.” Just under 20 years later, the Swedish owners decided to retire the original name and simplify it to plain “Seco,” just in time for IMTS.

In the meantime, of course, the goahead US-based international conglomerate Kennametal had purchased the Essenbased pioneering Widia company, which celebrated its 80th anniversary just a few weeks ago. How long, we might wonder, may it be before “Kennametal-Widia” follows the Seco-Carboloy trend into oblivion and becomes just plain “Kennametal”? Sandvik Coromant can generally be relied on at IMTS, as with other major exhibitions, either to improve existing products, or to launch innovatory new hard materials. This year was no exception. Among the new inserts being displayed were two new-generation milling grades, GC1030 and GC4240 that are claimed to offer higher efficiency in steel milling. GC1030 uses a unique PVD coating to improve wear resistance, making it extremely versatile and reliable. GC4240 is based on a new but unspecified substrate with CVD coating, aimed at shoulder milling or any other demanding steel-

0026-0657/06 ©2006 Elsevier Ltd. All rights reserved.

milling operations that require high metal removal rates. GC1030 also performs extremely well in titanium and high-temperature alloys. A colourful combination (Figure 1) are GC1020 and GC3220, two new grades optimised for cast iron milling, but providing reliable and secure performance in other tough milling operations as well. GC1020 is intended for machining nodular cast iron and wet cast iron, with a unique PVD coating to improve cutting speeds and wear resistance, making it especially reliable in unstable conditions. GC3220 is said to have the thickest protective coating on any milling insert. As a result, the grade is recommended for the dry machining of grey cast iron, due to its high level of durability and wear resistance. Also of benefit to those working with steel, the new generation turning grade GC4225 optimises roughing and finishing operations in steel turning. GC4225 uses a combination of features to enhance reliability and productivity through better surface finishes, higher feed rates and cutting speeds and improved plastic deformation and crater wear resistance. As some names shrink or disappear, others amalgamate and grow. Having become world-famous with its extensive range of high-performance coatings and service centres, Balzers has now adopted the name of its parent company and become Oerlikon Balzers Coating. The company’s latest (“6th Generation”) coating is Alcrona aluminium chromium nitride, said to expand the performance envelope beyond the established TiAlN, AlTiN and TiCN. It can be applied either to carbide or to high-speed steel. But the super-fine levels of coating achievement that are becoming attainable through the application of nanotechnology were evidenced by the launch by Sumitomo of a new range of truly nanotech cutting inserts, referring not to the substrate microstructure but to the thickness of each of a multiplicity of coating layers. Already a Sumitomo speciality and smoother than most conventional coatings, the new Super ZX coatings have as many as 2000 alternating surface layers of titanium aluminium nitride and aluminium chromium nitride. Each dual-layer cycle is just 2.5nm thick, making total coating thickness only 5 micrometres. Regular readers of Metal Powder

metal-powder.net

Figure 3. YBG-series inserts have smooth nanostructured TiAlN coatings of 2-4µm thickness.

Report who’ve followed the work of Bryan Roebuck and colleagues at Britain’s National Physical Laboratory will know not to give too much credence to microhardness values obtained with (necessarily) tiny loads, but these coatings are undoubtedly extremely hard: 5200 HV (“similar to CBN”) is the claim, compared with alleged hardnesses of a mere 2300 HV for conventional coatings. Exceptional wear resistance is said to be combined with oxidation resistance and sufficient toughness to permit even roughmilling operations, with high feed rates and superior surface finish. Standard insert grades are ACZ310 for cast iron milling, boring, grooving and cut-off, ACZ330 for milling general and die steels, and ACZ350 for milling stainless steels. Other applications include endmills and HK-type Super MultiDrills (SMD drills) with replaceable carbide heads. The speciality of Swiss company Friedrich Gloor AG is the manufacture of high-precision, customised carbide tooling. The updated range includes constant-profile form cutters with logarithmic relief grinding; micro tooling in sizes down to 0.30mm diameter; threadwhirling tools with six indexable inserts instead of the customary three; and profiled inserts ground from standards or specials. Back in the drilling area, the ATI Stellram Division of Allegheny

Technologies introduced its new, patented, regrindable, HardCore solid carbide drill, with a centre of tough, chip-resistant micrograin hardmetal and periphery of much harder but still micrograin carbide, designed for maximum wear resistance. Manufacture is likely to be by co-extrusion. Because competitive, single-grade, drills must compromise between the properties needed at centre and edges, up to four times previous tool life is confidently claimed for the new designs. Similar considerations make endmills an equally useful application. Though never mentioned in the promotional material, the real competition is perhaps the non-regrindable coated solid carbide drill, where the entire drill body can be tougher than the HardCore centre, whilst the coated cutting edge is also harder and more abrasion-resistant at high speeds. China, major source of the world’s tungsten supplies, is developing a reputation for quality and progressive R&D, as well as for quantity and competitive prices. Most of the international hardmetal brands, such as Sandvik, Kennametal and Iscar, have built factories in China, not only for exports but also to service the fast-growing Chinese industrial base. Nevertheless, ZCCCT (Zhuzhou Cemented Carbide Cutting Tools Co Ltd), having now absorbed its largest Chinese competitor, Zigong, can com-

November 2006 MPR

31

pete on better than level terms with the best of foreign producers (Figure 2). Unsurprisingly, it probably has more workers than any other, but not at the expense of technology. Here are a couple of examples. A new series of coated YBG carbide grades with nanostructured, exceptionally smooth TiAlN (nc-TiAlN) coatings, 2-4µm thick were promoted at IMTS.

The intermediate grade YBG202, with ultrafine substrate, is suitable for milling, with fine-structured but probably lowercobalt grade YBG102 for finishing and the tougher YBG302 for rougher milling, parting, grooving and stainless steel machining. YBG203 is a further development, intended for stainless steel only. “Black diamond” inserts are not made of coal and contain no diamond, but

are indeed black and reflect Zhuzhou’s traditional Diamond trademark. The two grades – YBC252 for general-purpose steel machining and YBC152 for highspeed finishing – feature functional-gradient substrates, with cubic carbides greatly depleted in the surface layer. The coating combines a relatively thick layer of fibrous titanium carbonitride, followed by a topcoat of fine-grained alumina.

Back to basics at the talking shop Support of special interest groups is one of the most valuable functions of industry associations. Hardmetals in Europe is no exception...

A

now-traditional feature of the European Powder Metallurgy Association’s annual conference is the meeting of the European Hardmetal Group (EHMG) that precedes the formal sessions. But its name is almost a misnomer, as the meeting is open not only members but also to Europeans whose organisations are not members of the group, as well as individuals from other continents with an interest in hardmetals. This made for lively and informal discussion at the PM2006 meeting in Ghent, Belgium. Peter Brewin of EPMA and Steve Moseley of Hilti led off with a report on EPMA Working Groups and current projects. The latter mainly concerned education, especially of designers and other materials specifiers. Summer schools comprised an eight-day course, followed by an exam for those taking part. RET – Research Education Training – was another aspect of this coordinated activity, as were the hardmetals aspects of ‘e-learning,’ the second part of the Leonardo project termed “Design for PM.” Budget was 500,000 and the lead organisations were Fraunhofer IKTS Dresden (host for the 2006 Winterev), Sandvik and Liechtenstein’s Hilti. An appeal was made for case-history material to illustrate the

32

MPR November 2006

new instructional packages. Henk van den Berg’s presentation on worldwide industry demonstrated that commercial production was thriving and with it the hardmetal industry. Sintered carbide production had now reached 50 000 tonnes annually and was still rising. In Germany, where the European activities of his own company (Kennametal) were centred, sales of inserts had risen 9 per cent in the past year, whilst orders had risen 10 per cent. In Germany again, the largest producer of machine tools in the world, this key indicator had risen by 6 per cent. Astonishingly, minute and super-precision circuit-board drills, employed in millions, have simultaneously become a “commodity” and the most important market for so-called nanosized hardmetals. In just two years their unit price has slipped from a highly competitive 1.80 to an almost ridiculous 0.60. China was the area of greatest activity, where the dramatic pace of industrialisation has created an enormous ‘local’ market for advanced cutting tools. More than that, China’s position as the source of most of the world’s tungsten has created a desire to be much more than a mere source of raw materials. With the complete acquisition of Zigong in July of this year, Zhuzhou is

now far and away the premier player on the Chinese stage (seen in their impressive exhibit at Chicago’s International Manufacturing Technology Show in September) and already a major force in the world. According to Henk, China now has more than 250 carbide manufacturers, more than the rest of the world put together. In one of a series of audience participations, Peter Brewin called for ideas to help promote hardmetals, in engineering components as well as tooling. A general consensus showed enthusiasm for regional workshops for smaller companies. Brian Roebuck of NPL, organiser of the informal ‘Winterev’ technical meetings, reported on the 2006 event at Fraunhofer, Dresden. It had been agreed that future such events should take place at Centres of Excellence, in particular CRIF in Liège, France, and CETT in Spain. Suggested topics for future Winterevs included •Surface characterisation methods; •Coatings; •Process and performance modelling; •Structure/property models; and •Fracture, fatigue and contact response.

metal-powder.net