Deep knowledge

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Cirencester is Sandvik Coromant's new Global Application Centre for Deep Hole Machining. Andrew Allcock visited and reveals the company's ambitions for this small, specialist activity [extended version of magazine feature, with video]

Cutting tool giant Sandvik officially opened its Global Application Centre for Deep Hole Machining, in Cirencester, on Friday 21 May, with press attending a day earlier to hear about the company's plans for the new activity. The setting up of this operation follows the acquisition by Sandvik, in 2008, of deep hole machining specialist BTA Heller Drilling Systems. "The acquisition is in line with Sandvik's long-term strategy for profitable growth. Through the acquisition, we intend to further develop the global business for deep hole drilling tools and strengthen our offer within the aerospace, energy and primary metal segments," said Anders Thelin at the time, who is president of Sandvik Tooling, a division of Sweden-headquartered Sandvik AB and represented in the UK by Sandvik Coromant UK, Halesowen (0121 504 5400). At the opening of the operation, housed in a modern new building on an industrial estate in Cirencester, it was Sandvik Coromant UK's new managing director for the UK, as of 1 August, Magnus Ekbäck (currently vice president R&D) who kicked off proceedings, explaining the new application centre's raison d'etre. The Cirencester facility is, in fact, part of a trend that has seen the tooling company set up a number of application centres globally over recent years. "There is starting to become a void in certain knowledge and competence within our customers and that is related to experience and knowledge about manufacturing practices and even more basic engineering practices. Someone has to fill that void, and this [its application centres] is our approach to doing so," Mr Ekbäck opened. In addition, the rate of change in industry is increasing, and the location of such facilities close to customers allows the company to accelerate its product development, in comparison to having a centralised R&D function, the soon-to-be UK managing director added. That said, not all Sandvik Coromant's application centres have this product development element, and Mr Ekbäck highlighted that this new facility would combine the activities of development and application centre. WHAT'S IN A NAME? The choice of name for the Cirencester facility, deep hole machining, as opposed to deep hole drilling, also underlines this process/product development element. While deep hole drilling is typically concerned with ops 10 and 20 – so drilling and counterboring – additional processes beyond this, such as creating more features within a component, is where machining comes in. These extra operations can also be undertaken on deep hole drilling/boring machines and, typically, require the development of bespoke tooling (Sandvik Coromant already has a standard products catalogue, having been in this market are for some 40-odd years). So, product and process development for part families or for features found across many families will be a focus for Cirencester. This product/process development element was ably underlined by Tony Evans, senior manager, business development and one of the original owners of BT Heller Drilling Systems, during a tour of the application centre's demonstration area. Image: Tony Evans, one of the original owners of acquired firm BT Heller Drilling Systems, seen here in the demonstration area alongside the rebuilt Craven deep hole boring machine Image: Another view of the demonstration area The area houses a Craven deep hole boring machine, re-engineered by PTG Heavy Industries (01422 379 122), with a capacity of 600 by 2,500 mm (part diameter by length) and able to produce holes from 10 to 150 mm diameter, counterbored to a maximum of 300 mm diameter. ALL-IN-ONE SOLUTION Above the machine is a drawing of an oil industry drilling collar of 10 m length. Too big to be an actual demonstration part for its machine, it features seven individual diameters and transition features between each of them. Concentricity is 0.100 mm, diameter tolerance 0.050 mm and surface finish required is Ra 0.8. Typically, this part would have been produced in multiple operations on multiple machines, including deep hole drilling. Mr Evans points out that the component's internal features could be completed in one set-up on a deep hole drilling machine. On the machine, however, was a demonstration of the internal machining of a chamber within a deep hole (video here). The production of such chambers is not new, Mr Evans explains, but the demands for this particular example were, with the solution shown just 6 months old. The demands included the ability to machine the exotic material, so a challenge for tool wear, concentricity and surface finish requirements. The latter meant that support pads that ride (rub) on the machined surface could not be employed. The demonstrated solution sees a special turning head that features both an expanding/retracting single-point cutting unit and hydraulically operated support pads within a rotating body. So, the bore is first drilled, then the turning head is fed down the bore; at the appropriate point, an X-axis (coincident with the drilling Z-axis) is used to expand/retract a turning tool to generate the chamber under CNC control; when the turning head requires it, hydraulically-driven support pads spring out from the cutter head, resting on the just-cut surfaces, but are held within a rotating body such that the pads are stationary on the bore surface, rotating with the component. Additionally, the hydraulic mechanism that drives the pads, which is located behind the drilling spindle, features a linear measuring scale that indicates what the chamber diameter is, allowing for remachining, should that be necessary. Mr Evans, along with previous co-owner, Simon Lawes, now senior manager, together with all previous staff have been retained by Sandvik. Indeed, it is from within this team that solutions for such challenges spring. In fact, before the acquisition, BT Heller Drilling Systems' business was 60 per cent such specials and 40 per cent standard tooling, it is advised. In addition to developing such products and applications knowledge, the challenge will be to transmit information to both other Sandvik personnel and to customers. This will be aided by the use of four video cameras located on the machine (one fitted as at Machinery's visit), while the CNC screen display can be transmitted to any PC screen. Image: The control's display can be shown on a PC screen on the wall of the demonstration area, with the same view transmitted around the world SENSE AND SENSOR-BILITY As an aid to helping Cirencester develop robust, reliable processes, the Craven is also fitted with a number of sensors. These log parameters, such as spindle torque load, coolant volume, coolant pressure, thrust and vibration. With this information, decisions about process parameters and tooling can be made, based on scientific information, as opposed to 'black art' deep hole drilling experience. Mr Evans pays tribute to Sandvik for supporting the investment in this facility in such challenging times, including backing a recent, speculative investment in equipment that will allow development of further novel solutions. Indeed, the combination of hard-won, hands-on experience that is embodied within the members of what is today Sandvik's Global Application Centre for Deep Hole Machining is now clearly being 'leveraged' by Sandvik's financial strength, its commitment to R&D and, a key element it was underlined, the availability of latest, leading edge carbide grades. "We have an amazing opportunity here," Mr Evans enthused, adding that the Cirencester facility is "the only one of its kind in the world". Putting this in some sort of context, Mr Ekbäck suggested the global deep hole machining market would be around £100+ million in two to three years; in 2007, BT Heller Drilling Systems had a turnover of around £3 million; Sandvik AB's turnover in 2009 was £6.3 billion, its tooling division's £1.68 billion. The opportunity does indeed seem clear. First published in Machinery, June 2010