20 July 2012
The cut and thrust of automotive
Steed Webzell takes a look at machining technologies in the automotive sector, discovering strong investment levels persist, despite a somewhat bumpy road to recovery
Of all the industry sectors, automotive seems to suffer most when it comes to dips in consumer confidence. However, despite the unwanted recent downturn and the stuttering return to growth, machine shops in the automotive supply chain have demonstrated an ongoing commitment to investment. A case in point is Dorset-based MJB Precision Engineering, which, having secured a large automotive contract, had to analyse the best way of producing four different tool steel parts in batches of 3,000 per week each, which are assembled into a new product for luxury passenger cars. The company had to take into account that quantities were set to rise steeply throughout 2012.
The 15-employee company's chosen solution was a 22 mm capacity Index CNC multi-spindle automatic from Geo Kingsbury Machine Tools (023 9258 0371). Until the German-built MS22C six-spindle auto (pictured) arrived, the subcontractor relied on sliding- head lathes to produce components of 20 mm diameter and below, while single spindle, fixed-head lathes were deployed for diameters up to 300 mm.
At the outset, MJB began machining the components on three sliding-head lathes, 20 hours a day, plus lights-out running, six days a week. The company calculated it would take a further five sliding-heads to fulfil the new contract. Furthermore, the extra staff needed to operate the extra lathes would have raised overheads and consequently increased unit production costs.
The space and labour cost issues were resolved by installing an Index CNC multi, which can turn-mill in a 24-second cycle a component that takes a sliding head lathe 120 seconds to complete, representing a five-fold productivity increase.
The family of four automotive parts is now in the process of being transferred to the MS22C, which has a Scara back-working unit with synchronous pick-up spindle for presenting each parted-off component to dedicated back-working tools. The company reports other advantages besides the production rate. Says managing director Mark Bevan: "We find that the machine is more rigidly built than our single-spindle lathes, so vibration is minimised, leading to much better tool life. We typically machine 400 components on one of our sliders before a tip needs changing, whereas the number rises to 1,000-off on the Index."
Efficient turned parts production was also the ambition at Somerset-based Metaltech Precision, where investment in three new Doosan TT 1800SY twin turret, twin-spindle turning centres from Mills CNC (01926 736736) has significantly reduced cycle times on automotive parts for one of the company's commercial vehicle engine supply chain manufacturing customers.
The new TT 1800SY machines have helped Metaltech reduce part cycle times from 90 to 60 seconds. Each has a 65 mm bar work diameter and 22 kW, 5,000 rpm spindles (left and right), along with integrated Y-axis (±50 mm), C-axis capability and live tooling.
"The TT 1800SY machines give us much needed manufacturing capacity and flexibility," says Andy Riste, Metaltech's sales manager. "They have become the central mainstay of a proven and reliable machining process that we've developed. Steel bars [EN31] measuring 3 m in length are fed into the machines and simultaneous machining on both spindles ensures seamless, continuous production."
In Hertfordshire, precision cold forming specialist Dawson Shanahan is also experiencing an upturn in automotive business, a development that has just seen the company install a CNC machining centre from Yamazaki Mazak UK (01905 755755). The new machine (www.machinery.co.uk/41548) is part of an ongoing programme of investment and expansion that underpins Dawson Shanahan's long-term goal to grow organically by at least 15% year-on-year. The Mazak horizontal mill is designed to ensure high levels of precision and repeatability, and will be used both for finishing cold formed components, and for the manufacture of conventionally engineered parts.
ON TWO WHEELS
The motorcycle business is thriving, with more and more people taking to two wheels as they look to economise on fuel, all of which is good news for UK machine shops. Take Northampton-based GE Precision Engineering, for example, which has recently installed a new XR 600 5-axis vertical machining centre from Hardinge Machine Tools (0116 286 9900) for the finish-machining of crankcase assemblies for Norton 961 parallel twin motorcycle engines, this being a new engine design with push-rod valve actuation, three bearing crank and balancer shaft. GE now has the capability to complete up to 30 crankcases a week.
"Five-axis capability gives us a number of new dimensions for machining the crankcases in a single operation," explains managing director Garry Edwards. "Only a couple of very minor operations are needed on the casting before we set up the component on the Hardinge."
The XR 600 offers a popular entry into 5-axis machining. The standard spindle operates at 12,000 rpm, but there is a 15,000 rpm option with a belt and gearbox-free Weiss directly-coupled unit, which offers increased acceleration/deceleration times.
Another machining technology provider enjoying success in the motorcycle industry is Mapal (01788 574700). The tooling specialist is supplying all of the critical tools for the latest engine line retooling project at Triumph Motorcycles in an order worth over £75,000 (www.machinery.co.uk/39110) that covers more than 30 different styles of custom-developed tool, including replaceable blade, carbide and PCD types.
This success follows more than a decade of co-operation between the two firms. Today, Triumph Motorcycles produces 50,000 units annually, but just 2,000 in 2008. At the outset, one bottleneck was the machining of valve seats – Triumph engineers asked Mapal for proposals to address this problem and was duly presented with a solution that reduced the number of tools needed from five to just two, leading to a significant reduction in cycle time.
Because of this success, Triumph invited Mapal to supply around half of the tooling for its type 806 four-cylinder engine line, while, for the next new engine line, Mapal delivered a turnkey project that included all tooling. This was repeated on two more production lines for Triumph plants in Thailand. Mapal has since introduced Triumph to an innovative arrangement for valve guide and seat finishing that uses two tools for machining the valve seat and the valve guide complete. Now, Mapal is working with Triumph on an engine production line that is being completely retooled at the Hinckley, UK, plant.
Tools of the trade
Sumitomo Electric Hardmetal (01844 342081) has responded to material specification changes in the automotive industry with the development of two specific grades of turning insert for machining nodular cast iron. This material is being progressively adopted in preference to grey cast iron to produce thinner castings of lower weight used in the likes of brake discs, crank and camshaft components to help improve performance and fuel economy.
The inserts, Ace Coat AC405K and AC415K, are both CVD coated with Sumitomo's latest ultra-hard, multi-layer Super FF that is able to offer benefits of up to 50% improvement in wear resistance and overcome any tendency of the film coating to peel back. It also provides resistance to edge damage and chipping, while creating very low levels of chip adhesion (built-up edge).
Elsewhere, Walter GB (01527 839450) says its Tiger.tec Silver inserts show a 75% increase in tool life when face milling GGG50 brake callipers using an Xtra.tec shoulder mill, while, for CGI finishing operations, the Auto AF 245 face milling solution from Sandvik Coromant (0121 504 5500) combines high bi-metal removal rate with mirror-like surfaces that the company says often dispense with the need for further operations.
First published in Machinery, June 2012
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Geo Kingsbury Machine Tools Ltd
Hardinge Machine Tools Ltd
Mills CNC Ltd
Sumitomo Electric Hardmetal Ltd