METAV 2012: Machine tools in miniaturised formats
METAV 2012: Machine tools in miniaturised formats
In medical technology and the watch-making industry less is more
Frankfurt am Main, 15. February 2012. – From macro to mini – that’s the bandwidth of special topics addressed at the METAV 2012 in Düsseldorf. They include the special show entitled “Metal meets Medical”, which illuminates the entire process chain involved in making technical medical products, for example. Miniaturisation, however, is a major focus not only in the field of medical technology; small parts are the next big thing in numerous different sectors. A prime example for high-precision machining of miniature mechanical components is the watch-making industry.
Less is often more – and even less is now hardly conceivable: solid-carbide micro-milling machines with diameters of just three-hundredths of a millimetre, even capable of milling hardened steels at HSC turbo speeds. Since medical technology has started to boom, machine tools in living-room or even smaller formats are increasingly in demand. The Darmstadt-based Datron AG, for instance, will at the METAV 2012 be showcasing its new high-speed C5 milling machine for ultra-high-precision five-axis simultaneous machining of small parts, in the fields of medical technology, for example, the watch-making and jewellery industries, or tool and mould manufacturing. All machinable materials up to a diameter of 60 mm can be simultaneously machined in five axes, with an option for milling ultra-complex geometries as well. The directly driven
rotary-swivel axis guarantees good reproducibility coupled with high process dependability – and all this on a footprint of just 1 m².
Precision en miniature
Compact and as accurate as clockwork – the tradition-steeped watch factory of Junghans GmbH & Co. KG in Schramberg, nestling in the middle of the Black Forest, is once again relying on its in-house expertise for manufacturing ultra-small mechanical parts as well: with a compactly dimensioned micro-milling model from Haas Automation for high-precision machining of filigree movement parts, it has revived the corporate tradition of exquisite wristwatches. After back in 1976 the firm had discontinued mechanical watch production entirely and concentrated on quartz movements and radio clock technology, the tradition-steeped enterprise in Schramberg was now keen to take know-how and technology into its own hands.
At one vendor, Managing Director Matthias Stotz noticed the OM-2 micro-milling machine from an American manufacturer called Haas Automation. Its advantages included not only a good price-performance ratio, but also the geographical proximity to the relevant machinery supplier and the Haas Factory Outlet, a firm called Dreher AG in Denkingen. The machine (OM stands for Office Mill) is so compactly dimensioned that it could be ingressed easily and without modification into the newly designed production premises and even afterwards can be moved around as desired. Its performance data, says Managing Director Stotz, “are not only more than sufficient for our field of work, which is manufacturing very small movement parts for mechanical wristwatches”, thanks to the standard high-speed spindle (up to 30,000 min-1) the machine is even “ideally suited for machining our small parts”.
A multitude of ultra-filigree small parts
The traditional materials used in watch-making are brass and steel. On this compactly dimensioned high-precision machine, a multitude of ultra-filigree small parts are nowadays being manufactured for the calibres of exquisite upmarket wristwatches, such as brass parts that have to be machined on two sides, like gear bridges, balance bridges or calibre bridges. Plus gear parts made of steel like crown wheels or ratchet wheels. A crown wheel, for example, with crown gearing and spur gearing, may exhibit a definitely complex geometry. It is machined in the standard four-axis version of the model with an indexing device.
All the high-precision parts produced on the Haas machine are then craft-reworked or “finished”. This, says Stotz, differentiates value creation in sophisticated watch-making from general mechanical engineering: “What matters to us is not the last second of the machine’s running time. Our primary focus is on quality and precision.”
Watch-makers think and work in dimensions of hundredths, though accuracy alone is not the most crucial factor – this is the miniaturisation of the parts involved – and this with tolerances of e.g. 5 to 8 µm for gear components. The exquisite “Erhard Junghans 2” model, for instance, has a balance mechanism developed in-house, featuring “wafer-thin wall thicknesses and a tiny screw with a thread of 0.3 mm”. Dimensions like this are a genuine challenge for a mechanical manufacturing process.
The tools used merit some special attention. In the case of miniature milling machines featuring a high-speed spindle with diameters of “significantly under one millimetre”, the useful lifetime is also an issue. Often solid-carbide tools are used, preferably standard products available on the market. “We make only a few specialised tools ourselves”, explains Stotz.
The batch sizes of the parts manufactured on the micro-milling machine are currently between about 15 and 20. But for Junghans what’s important for mechanical upmarket watch-making is “less the quantitative considerations than on developing and building up a fund of in-house expertise”. The four-axis version fully suffices for the current production operations. Here the machinery supplier Martin Dreher, Board Chairman of Dreher AG, interjects that a fifth axis can be retrofitted at any time: “The control system has already been prepared for this in the factory.”
Author: Walter Frick, specialist journalist from Weikersheim
Datron AG, Mühltal
Datron AG is an internationally operating mechanical engineering company listed on the stock exchange, located in Mühltal-Traisa. Its core products are CNC machine tools for high-speed milling and 3D engraving, dental milling machines for efficient machining of all the usual orthodontic materials in dental laboratories, dosing machines for fast and accurate gluing and sealing, tools for high-speed machining and after-sales services like training, customer support, accessory and spare part sales. Approximately 24 per cent of the employees work in research and development, enabling the company to react swiftly to new market trends and the machining of up-to-the-future materials. Datron AG has approximately 160 employees in Germany, and a global sales network in more than 20 different countries. In 2010, the company achieved a turnover of around 21 million euros.
Haas: a transparent sales concept
Haas Automation Inc. in Oxnard/California, USA, started off producing turntables and CNC lathes. Today, the product portfolio includes about 90 different models of lathe and milling centres. The current monthly output is approximately 1,200 machines, giving Haas a market share of about 48 per cent. Sales are handled on the HFO concept (Haas Factory Outlet). The HFO responsible for Junghans is Dreher AG in Denkingen as a licensed service and sales partner. Dreher buys machines plus accessories at Haas’ European headquarters in Brussels, and markets them as an autonomous machinery trading company in line with harmonised marketing, pricing and service support stipulations. In the south of Württemberg, Dreher provides support for about 1,200 machines at around 500 customers.
Junghans: 150 years of watch-making craftsmanship
The Junghans company was founded back in 1861 by Erhard Junghans and his brother-in-law Jakob Zeller-Tobler in Schramberg, Germany. While the company specialised at first in manufacturing individual parts for watch production, by 1866 the first watches were already being designed and built by Junghans’ watch-makers, inspired by industrial watch manufacture on the American model. By 1903, Junghans was employing 3,000 people, selling three million watches a year – and was the world’s biggest watch factory. In the 1930s, the first models of the legendary “Meister” line were being produced. In 195 6, the Diehl Group in Nuremberg acquired a majority shareholding. In 1970, the first German quartz wristwatch was unveiled: the “Astro-Quartz”.
The quartz crisis of 1976 triggered a temporary demise of the mechanical Junghans watch, and a change-over to dedicated production of quartz models. Innovative emphases were highlighted in 1990 by the world’s first radio wristwatch, the Mega 1. Other milestones included the first radio solar watch in 1993, the first multi-frequency radio watch in 2004, and the resumption and expansion of the mechanical collection in 2008. At the beginning of the new millennium, the Diehl Group sold Junghans to the Egana-Goldpfeil Group, headquartered in Hong Kong. In 2008, the parent company in the Far East had to file for bankruptcy, but by January 2009 a family of entrepreneurs in Schramberg called Steim, co-proprietors of the globally operating Kern-Liebers Group, Schramberg, took over the Junghans watch factory and made a fresh start with around 90 employees.
METAV 2012 in Düsseldorf
The next METAV will be held from 28 February to 3 March 2012 in Düsseldorf. In the even years, it has firmly established itself as an important technology shop window for the entire gamut of manufacturing technology and automation in Germany for manufacturers and customers from Europe. The METAV will be showcasing the entire spectrum of manufacturing technology, focusing on machine tools, production systems, high-precision tools, automated material flows, computer technology, industrial electronics and accessories. The METAV’s visitor target group includes all major industrial sectors, particularly plant and machinery manufacturers, the automotive industry and its component suppliers, aerospace, the electrical engineering industry, the metalworking sector, medical technology and the craft sector. Approximately 620 exhibitors from 26 different countries have meanwhile registered for the METAV 2012, on over 35,500 m2 of net exhibition area, aiming to showcase their products, solutions and services for the European trade public. The last METAV in 2010 attracted approximately 45,000 trade visitors from 26 different countries.
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