Safety critical machining of fuel injection components in large series, or universal machining of small series, always within tolerances of a few microns: these are the jobs for internal grinders.

Safety critical machining of fuel injection components in largeseries, or universal machining of small series, always withintolerances of a few microns: these are the jobs for Studerinternal grinding machines, which are built in differentversions. On the S145cnc with up to four spindles, for instance,complex components in small and average series can be groundeconomically. Featuring a centre height of 175mm a maximumgrinding length of 200mm and a substantial table load, themachine is suitable for a wide range of applications.

Grindingspindles according to requirements of 24000 rev/min to 120000rev/min installed on the indexing turret head allow high-accuracymachining of bores up to diameters of 200mm and the manufactureof smallest bores of less than 3mm in diameter.

This is the idealmachine for the production of small and average series as well asfor mould making applications.

For internal production grinding,the S140cnc is available.

Based on its modular concept, thismachine is suitable for a large number of production tasks.

Thestandard version is equipped with hydrostatic guide-ways; thisbasic version of the Studer S140cnc provides the ideal basis forhigh accuracy machining.

Simple machining tasks with one grindingspindle can be achieved by means of the S140 modular kit, as wellas complex elements including simultaneous external and internalmachining.

Reductions of cycle times of up to 40% can beobtained.

Specially adapted machining modules, such as internaland external grinding spindles, workheads and different dressingattachments, can be installed on the standardised machine tableaccording to requirements.

The machine tables with hydrostaticguide systems, in conjunction with the optional, alsohydrostatically- operated drive spindle guarantee a smooth motionand perfect surface quality of the workpiece.

Up to threeinternal grinding spindles with ceramic bearing systems andspeeds above 100,000 rev/min installed on a slide allow machiningof extremely small bores to the narrowest tolerances.

Roughingand fine machining can be carried out without time-consumingindexing of a revolver.

Simultaneously to internal roughgrinding, finish grinding of external diameters or surfaces canalso be done.

The installation of a handling system withintegrated gauging and palletising units converts the S140cncinto an unmanned machining centre.

In three shifts and seven daysa week, elements for diesel injection systems, for instance, inhighest quality, can be machined.

Ceramic? Silicon? Quartz? Glass? Tungsten? - whatever the hard or brittle material, slicing and surface grinding and vertical profile grinding machines perform consistently and accurately.

Chevalier (distributed in the UK by Dugard Machine Tools) offerthe essential hi-tech grinding machines for high-precision andefficient performance across a large range of industrialapplications. Ceramic? Silicon?

Quartz?

Glass?

Tungsten?.whatever the hard or brittle material, the Chevalier range ofslicing and surface grinding machines and vertical profilegrinding machines are designed to perform consistently andaccurately.

For example, take the FSG-H818CNC or the B818CNCmachines.

Both are high efficiency, high precision multipurposegrinders particularly suited to intricate profiles and moldcomponents such as those required in for aerospace, automotive,electronic, medical and defence applications.

Both provideexcellent rigidity and precise positioning with full Fanuc OMautomation - and both offer outstanding versatility for all typesof grinding (multilevel surfaces, punch, slice, plunge, pitch,side-wheel, profile, form, index and creepfeed).

Or there are theFSG-2040TC and 2060TC column type, high precision three-axissurface grinders.

These programmable machines provide rough orfine grinding for mass production.

The precisely balanced spindlemotors are air cooled to ensure accuracy and the wheelhead isfinely positioned to ensure downfeed repeatability to within0.002mm.

For two-axis, submicron surface grinding Chevalierprovide the ULTRA-H612CNC or the ULTRA-B612CNC.

Both of thesemachines provide mirror sufacing (surface roughness) to within0.25mm; a positioning accuracy to within 0.5mm and a grindingaccuracy to within 1mm.

The extra long guideway design of thespindle seats on these machines provides high rigidity and helpsto overcome the cutting resistance.

An optional linear scalesystem can be mounted on the column to compensate for pitch errorand to ensure accuracy.

For a smaller, multifunction surfacegrinder, Chevalier offer the SMART-H818 which is designed to meetthe needs of novice and experienced CNC operators alike byproviding the simplicity of a manual grinder and thesophistication of a CNC machine.

Without requiring complexprogramming codes, the SMART-H818 can still be programmed inG-code format or can download from a CAD/CAM system.

The tablespeeds vary from 0.02 - 25m/min.

Meeting the financial needs ofthe industry today - 'Cost is the major issue intoday's industry,' says Eric Dugard, Managing Directorof C Dugard.

'Our customers need accuracy, reliability,performance and high productivity - but at the right price.

Toenable them to achieve this we offer a range of innovative andpractical rental schemes and finance packages to help them spreadtheir investment over a period of time.

We also provide fullinstallation, support and maintenance packages - plus extendedwarranties - so that our customers can choose the option thatsuits them.

Flexibility is the key word in order to meet the everevolving needs of our customers.' 'As ourcustomers' requirements become more and more sophisticated,Dugard offers them the very latest in technology (both in themachines themselves and in the control systems) to help them stayat the forefront of today's industry.

At the same time, wemaintain our fundamental policy of providing affordable qualityplus performance.' CD-ROM catalogue - Eric Dugard adds,'Many of our customers have been requesting our new CD-ROMcatalogue of products.

This is a recent innovation for Dugard andit was particularly well received at the recent MACH 2002 show.While our website already provides up-to-date details on ourproduct ranges, services and financial packages, many customersprefer to use our CD-ROM in order to browse through our ranges(off-line) at their leisure.

This is just another way in whichDugard continue to make it as easy as possible for our customersto access the information they need.'

Two large angle 7in or 9in wheel grinders designed for cutting and grinding applications incorporate a two-step power switch at the rear of the tool, allowing users to tackle large jobs safely.

Two new large angle grinders designed for both cutting and grinding applications have been introduced by Metabo. Featuring a 7in or 9in wheel, the W23-180 and W23-230 grinders incorporate a two-step power switch at the rear of the tool, allowing users to tackle large jobs safely. Users must have the first button depressed to engage the power switch, preventing accidental turn-on during operation.

The tools feature a flexible rear handle that rotates 90deg for comfort during cutting operation.

A 3-position side handle for left- or right-handed operation allows users to turn the tool 90deg to cut vertically, while still having a firm grasp on the grinder.

The grinders incorporate Metabo's Marathon motor with epoxy resin powder-coated field coils, which make the motor extremely resistant to destructive grinding dust and help prevent overheating.

Also included in each grinder is a winding protection grid that deflects harmful airborne debris away from armature winding, increasing motor life by up to five times.

The grinders feature an easy-to-use wheel guard that requires no tools to adjust, and auto-stop carbon brushes for longer service life.

The W23-180 is rated at 2,300 watts, has a torque value of 124in.lb, operates at 8,500 rpm using a 15.0A motor, and weighs 13.3lb.

The W23-230 is rated at 2,100W, has a torque of 150in lb, operates at a no-load speed of 6,600 rpm using a 15.0A motor, and weighs 13.6lb.

Hydrostatic bearings in surface grinding machines have programmable variable pressure to achieve flatness and straightness levels within 0.5 micron/m machine table stroke.

The latest 'groundbreaking' development in adding programmable variable pressure to hydrostatic bearing technology by Okamoto of Japan, the world's largest manufacturer of grinding machines, enables some four times greater levels of rigidity to be obtained over conventional surface grinding machines that use hydrostatic bearings. As a result, flatness and straightness levels within 0.5 micron can now be held per metre stroke of the machine table in the latest UPG-84NC Ultra Planarization surface grinder while supporting table loads up to 700kg. Now available from the 600 Centre of Shepshed near Loughborough, the UPG-84NC is the most compact of the latest UPG machine range of 13 machines which can be specified having table lengths up to 4000mm and all are capable of generating the same degree of flatness.

The technology was originally developed by Okamoto's special purpose application engineering team to create a new order of 'mother' machine capability with minimum inertia and vibration when the table reverses.

The idea was to create new orders of flatness and straightness for production grinding its own surface grinding machine tables, beds and bearing guide rails.

The latest UPG range is ideal for grinding tasks such as dies, master granite surface plates, metrology equipment, LCD and semiconductor production.

All the machines in the range have been completely re-designed using totally enclosed stainless steel guarding giving easy access to the grinding area.

The programmable Okamoto 'non-contact' hydrostatic slide system reduces the oil supply to the bearing by one-third of a conventional hydrostatic system and improves the strength of the guideway structure of the machine giving improved table loading performance.

As a result, it achieves a consistent level of accuracy throughout the grinding plane giving a longitudinal straightness of 0.5 micron/1000mm and 0.4 micron/800mm on the cross axis.

In addition, it is possible to establish a minimum 10Nm input increment and work within a resolution of 2Nm in both axes.

Traditional hydrostatic slideways vary the thickness of the oil film layer formed on the surface of the guideway according to the load on the table.

Maintains Okamoto, by controlling this oil film layer grinding accuracy can be improved by some 400%.

Also, by avoiding high levels of hydrostatic oil pressure combined with traditional temperature control techniques, this significantly reduces running costs of the machine.

Automatic compensation is applied to the Okamoto slideway bearings that have six faces all under variable hydrostatic control through the Okamoto developed software in the Fanuc 31i Model A control system.

The hydrostatic oil, hydraulic oil for the table longitudinal axis drive and the coolant fluid are all temperature controlled on the UPG to within +/-0.1 deg C and an ultra-accurate hydrostatic spindle is also part of the standard machine specification.

A recent Okamoto grinding demonstration on a larger UPG 408 NC machine, able to accept a table load of 5.5 tonnes, illustrated how a coating roller die some 2000mm long could be ground to a flatness of 0.15 microns.

Normally a die of this type, which is used to apply glue to postage stamps, is ground, lapped by hand and polished to achieve a flatness of 0.3 micron.

The UPG-84NC has a table size of 850mm by 400mm and an electro-permanent magnetic chuck size of 800mm by 400mm by 100mm.

Grinding wheel size is 305mm by 38mm by 127mm driven by a 5.5kW motor and distance between wheel and table surface is between 50mm and 550mm.

The X-axis longitudinal table speed is variable between 0.3 and 25m/min, vertical and cross-feed rate is between 1 and 790mm/min.

The Fanuc 31i-MA control provides two-axis simultaneous movement in Z and Y and interpolation in the X-axis.

Options include automatic dynamic balancing of the grinding wheel, linear glass scale feedback for the vertical axis, gap elimination and a table longitudinal axis crowning.

Why higher production rates using plated CBN abrasive grinding wheels cannot be achieved may be the spindles are not fast enough and the machine requires fast set-ups and high rigidity.

Enterprises that are willing to pay up to ten times more for CBN grinding wheels expect a large payback in terms of faster material removal, or more parts per wheel, or better form consistency, and usually all three. However, although it might seem easy to add a high speed spindle to an existing machine to take a CBN wheel, the user might then find that his parts have surface finish problems caused by the machine vibrations and chatter, which can occur at these high speeds. This is not usually a problem with the abrasives; rather it is with the machines onto which the CBN wheels are applied.

Fitting new high technology wheels onto old or existing machines is almost certain to result in the wheels not achieving their production potential, leading to disappointment for the user.

The most obvious reason why higher production rates cannot be achieved on conventional machine tools is that the spindles simply don't go that fast; but there is also another reason: the machine must be designed for fast set-ups and with the accuracy and stiffness that anticipates such elevated process speeds.

The same problems do not apply to machines designed specifically to employ the latest plated CRB wheels.

Holroyd's Edgetek range is a good example: the machines are produced with high power/high speed spindles that optimise the use of plated CBN wheels at surface speeds of up to 9000m/min.

This enables them to achieve high depths of cut and optimised metal removal rates far exceeding those of more conventional machines, such as CNC lathes, milling and machining centres and grinders.

In addition, the Holroyd Edgetek machines are manufactured with a polymer granite base, which has been shown to have strong damping properties.

These have been proven in dynamic response tests carried out by AMTRI.

Developed to satisfy the need for extreme rigidity and enhanced vibration damping, the polymer base typically weighs 3 tonnes and has no resonant frequency.

As a result, it enables higher precision machining to be achieved.

Combining this stiffness and damping capability with the Edgetek's ultra high speed machining capabilities and plated CBN wheels, is drastically reducing cycle times in many crucial industry sectors.

In one example, the cycle times for producing automotive parts manufactured from sintered metals were reduced from 70s per component to just 22s.

At the same time, the Edgetek's plated CBN technology is cutting consumable parts costs, achieving a reduction from US$1 to just 3.3 cents per component.

This is the result of the Edgetek machine producing a much larger number of components between tool changes: 15,000 as opposed to the 50 achieved with conventional milling and turning machines.

In another UK application, a single 5-axis Edgetek machine is slashing process times with single lift and set-up.

The Edgetek is replacing seven conventional milling and grinding machines, providing a reduction in the throughput time for a complex finished part from 8h to just 12min.

'This application epitomises lean manufacturing technology,' said Holroyd sales director, Neil English.

'It provides the opportunity to begin with a hardened blank, and then produce a part complete in a single set-up, using plated CBN wheels.

It is not the cost that is driving the trend toward plated CBN but the productivity,' said English.

'Smaller production runs and more set-ups, means that many companies no longer have the luxury to amortize the cost of bonded wheels, and the long non-productive set-up times associated with them, over extended production runs.

Plated technology fills the need for high metal removal rates with short set-up times and eliminates the need for dressing.

The plated CBN form wheels we use on our Edgetek machines have several advantages over bonded conventional or superabrasive wheels: they have higher material removal rate capabilities, and are freer cutting, which reduces thermal metallurgical damage to the work's surface.

Equipped with steel cores they are also safer, providing safety at high operating speeds in excess of 20,000 sfm.' He said: 'In addition, plated wheels offer the highest levels of consistency: they grind virtually the same profile, from the first cut to the last, across hundreds or thousands of workpieces.

As a result, the times associated with set ups, wheel changing, and wheel dressing are significantly reduced or eliminated.

Also greatly reduced is the average wheel cost.

This is because the wheels can be stripped of worn CBN and re-plated several times.' * Unequalled levels of precision and productivity across almost all part types - the flexibility of the Holroyd Edgetek design, and the huge variety of machine types and multi-axis configurations available, enables the machines to provide unparalleled levels of precision and productivity in the manufacture of almost any type of parts - gears and sprockets, rotors and impellers, medical instruments, hand tools, air foils and nozzle guides, airframe actuation components, ducting supports, mechanical seals - and many, many, more.

The machines serve a broad spectrum of industry types, including power generation, automotive, aerospace, medicals, tools and general engineering.

They can be tailored to suit specific applications and supplied as complete turnkey solutions as part of a manufacturing cell.

A worldwide service network provides support for the machines, and they also benefit from manufacturer- developed preventative maintenance plans.