Horn’s tooling technology treats

Paul Horn GmbH's global headquarters and technology centre at Tübingen, some 30 km south of Stuttgart, Germany, played host to a veritable feast of machining technology demonstrations and new applications during three days in May. Over 1,500 customers, suppliers, local dignitaries and press attended the event, which bounced back to full strength this year, following a subdued showing last year, courtesy of the volcanic ash cloud debacle. Image: Horn invests heavily in its manufacturing facilities Live cutting demonstrations were supported with a series of informative technical presentations, each looking at a key topic within Horn's area of expertise. The first examined chip control with process and material-oriented geometries for grooving, side turning and parting-off. When grooving/machining between two flanks, chips can be transported only in two directions and, for this reason, Horn considers the development of application-oriented chip-shape geometries as one of its most important objectives. The presentation showed how cutting edge geometry, with its fillets and chamfers, has the greatest influence on chip shape and direction. The chip breaker, with its cavities or steps, guides the chips, while chip grooves in the tool body exert additional control. Here, Horn can offer extensive material-related forms, based on some 28 standard geometries. Out in the machine shop, a Traub TNA400 turning centre (available from Geo Kingsbury Machine Tools – 02392 580371) was demonstrating Horn's range of geometries for performing operations that included: profiling; grooving and face grooving with full cut; grooving with full and partial cut; grooving and side turning; and parting-off. SPECIALS AND COMBI-TOOLS The second presentation of the day provided a tour through the world of Horn special and combi-tools, which aim to save time and cost by combining several machining operations into one insert, as a special tool, or combining various inserts into a single combi-tool. These tools are finely adjustable and often feature integrated cooling. Examples are combi-tools for lathe finish-grooving, and tools in which ISO cutting edges are combined with Horn inserts to reduce machining and non-productive times. One example is slotting an internal multiple edge. Here, special multi-edge broaching tools with replaceable cartridges offer distinct advantages for large components and, with this in mind, Horn has developed a modular tool with a replaceable cassette. Two small inserts guarantee the cut division required to produce smaller chips. The offset slotting reduces cutting force significantly, while an integrated coolant feed assists chip removal. Image: Modular, cartridge-based cutting tools are a productive solution offered by Horn Other special solutions include tools for: precision plunge cuts and form plunge cuts; milling graduated grooves; internal and external flange machining; forward and back-boring, with one spindle and no tool change; and valve machining. Horn offers a five-day delivery for special tools (coated), depending on quantity, which, it claims, is the fastest in the industry. Image: Plunge cut plate S117 (left) and a triple-edge tool S315 (right) with profiled form Emphasis for the next presentation shifted to coatings, with rare insight provided into the production process. Horn views in-house coating as a core competency and a basic prerequisite for the manufacture of effective, task-specific standard and special tools. The company says that its proprietary facility reduces the overall cycle time of a tool by two working days, compared with external solutions. Image: In-house coating - a core competence To be able to adapt the coating to its range of products and materials, Horn uses 'sputter' (cathodic sputtering) plants that are able to apply the various coatings, either individually or in combination. For the various insert types and batches, Horn employs six plants, with an average fill level of 1,400 units and two plants with an average fill level of 6,000 units. The sputter plants reach temperatures of around 450-500°C, and cycle times vary between five and 13 hours, depending upon coating thickness. SERENDIPITY Horn stumbled into broaching, the subject of the following presentation, almost by accident. Broaching was used originally to help make Horn cutting tools, but the company wanted to devise a better, self-aligning solution suitable for all CNC lathes and milling machines. With regard to DIN and special groove profiles, Horn has three insert sizes available for broaching keyways in tolerance classes JS9, P9 and C11. Thanks to their four cutting edges, the corresponding toolholder shanks can be inserted, regardless of the machine's axis position. Alternatively, they are also available with shanks or holders in accordance with VDI, Capto or HSK. Tapers and helical grooves can also be slotted, using programmable C and X-axes. In the machine shop, a DMU50 evo machining centre from DMG (01582 570661) was busy performing broaching tasks using Horn technology – with a three-component dynamometer from Kistler (01256 741550) being used to measure the chipping forces. The focus of a further presentation, centring on turn and groove milling, was Horn's recently introduced System DC – essentially a series of solid carbide groove tools with two, three or four cutting edges on a single row of teeth for the production of threads, grooves with round or square cross-sections, and chamfers. System DC tools can produce threads with full or part profile, conical threads, right/left hand threads and threads with variable pitch. Available in several carbide grades, the cutters are particularly adept at machining materials used in medical applications, such as cobalt-chromium steels, titanium and surgical stainless steels. A number of the demonstrations were set up to show Horn's expertise in threading, including trapezoidal and ISO metric fine threading operations on a Gildemeister CTX Alpha 500 CNC universal lathe; and thread whirling of a stainless steel orthopaedic screw on an EvoDeco 16A sliding-head lathe from Tornos (01530 513100), using Horn's M302 system. ECONOMIC BORING The final presentation centred on economic bore machining, and here the Horn range includes various tools according to the type of machine tool being used. The exchangeable-head System DD (yet to be launched in the UK) offers nominal diameters of 12-15.9 mm in 0.1 mm increments for drilling depths of 3xD and 5xD. Alternatives include the high feedrate milling cutter System DAH with indexable inserts, and System DA with indexable inserts. Image: System DA with indexable inserts One of the key demonstrations showed some of these systems in action. Taking place on a Gildemeister GMX250 linear turn-mill machine (DMG, 01582 570661), turn and groove milling using System DAH, bore machining using System DD and broaching operations were all helping to machine an eccentric shaft from 60 mm bar. Other hole making technology on offer from Horn includes: Super Mini for boring-out and grooving; precision machining with reaming System DR; and bore machining with MCD. While almost all production engineers will be familiar with PCD (polycrystalline diamond) cutting tool technology, MCD (monocrystalline diamond) tools are able to produce surface finishes that eliminate the need for subsequent polishing. Precise geometric contours with peak-to-valley ratios of Rz =1 µm can be achieved. According to Horn, these values are impossible using conventional HN, CBN and PCD tools. Materials such as nickel, brass, aluminium, copper, bronze and plastic can all be machined. The only restricting factor is that workpieces must be non-ferrous. Touring the remainder of the demonstrations, there was plenty to catch the eye. For instance, while a Gildemeister CTX Gamma 2000 turning centre busied itself with external front and back machining, grooving and turning of cast aluminium alloy wheels, the machine opposite, an F208 KS Magnum 5-axis machining centre from Chiron (available from Engineering Technology Group – 01926 818418), was engaged, producing precision milling and drilling operations on watch movement base plates. PARTNERS IN PRODUCTION There were also plenty of partner companies in evidence, one of which, Graf Werkzeugsysteme GmbH – a provider of tooling for Swiss-type and multi-spindle turning machines, will be represented exclusively in the UK by Horn Cutting Tools Ltd (01425 481800) from 1 June onwards. In the view of Andreas Vollmer, Paul Horn GmbH's sales director, the technology days at Tübingen proved a roaring success, providing a sound platform for the launch of several new products at EMO 2011 in Hanover later this year (19-24 September). Among the highlights will be milling cutters with narrow widths, holders and with through-coolant for grooving on lathes, and new threading technology specifically for the oil industry. "The oil sector is an area where we have made significant gains in the past six months," he states. "Another very strong area is automotive, and both aerospace and medical are showing rapid growth, too." Mr Vollmer says the company is also working on hard metals and coatings to develop a range of solutions for cutting abrasive composite materials, which it sees as a long-term aim. "The ambition with all of our projects is to show how traditional manufacturing markets in Europe and North America can compete with competition based in low-cost economies," he says. "However, there is a generation of engineers growing up who don't understand that a more expensive tool doesn't mean a more expensive process. We have to battle this perception almost constantly." Box item Rounding (up) the horn Paul Horn GmbH is privately owned and has had a presence in the UK (Horn Cutting Tools Ltd) since 1996. Of the organisation's 820 employees, 650 are based in Germany (around two-thirds are production staff). In 2010, worldwide sales were €170 million (up 38% on 2009), of which Germany accounted for €103 million. This year, Horn expects to see revenue growth of over 20%. Horn's 1,200 m2 apprentice training school in Tübingen currently has 85 trainees spread across a four-year programme. Annual recruitment of around 20 new trainees is routinely over-subscribed. Last year alone, the company invested €8.5 million on machine tools from DMG, solely for use in the apprentice training school. The company completed a 5,500 m2 two-storey factory building extension in 2008 – doubling the available production space to 11,000 m2. In mid-2010, Horn placed an order for 100 new grinding machines, which are purpose-built by DMG and are being delivered at a rate of two per week. Another €30 million (5,000 m2) facility, intended to produce Horn's carbide insert blanks has just been completed and will come on stream later in 2011, bringing with it 30 new jobs. Image: The current Paul Horn GmbH factory in Tübingen, Germany In the next five years, Horn will add another 5,000 m2 for administration and a further 10,000 m2 for production at its Tübingen site. The company also manufactures in France, the USA, the Czech Republic and the UK. In fact, Horn has identified that the UK subsidiary will relocate to a new site near its existing location in Ringwood, Hampshire, by 2013-14. This will feature at least double the existing manufacturing capacity.