The innovative ‘Flat-Pack’ design of theBosch new generation LI-X compact

automotive alternator increases powerdensity by 35 per cent. This provides thecapacity needed for an increasingnumber of electrical loads and is also thebasis for integrating new vehicle safetyand operating functions. And withgenerating efficiency now boosted to 70 per cent, a fuel saving of up to 0.5 litres/100 km is achievable, coupledwith a significant reduction in emissions.

Production of compact vehiclealternators at the Miskin (Cardiff) plantbegan in 1991 and current output isaround four million units a year.However, the introduction of the LI-Xalternator in 2004, backed by an initialinvestment of €25 million, signalled thegradual replacement of the previousdesign and drove the decision to invest afurther €50 million in productionequipment during 2006/2007.

As part of this on-going investment,eight Mazak IVS 200 inverted verticalspindle turning machines in two lines arenow dedicated to the machining of thestator assemblies for three sizes of LI-Xalternator. Yamazaki Mazak UK took onthe role of project manager, reporting toBosch process engineer, David Hamilton.

The eight IVS 200 machines areessentially standard CNC machine tools,

albeit designed specifically for largebatch, mass production applications, sothey can, if circumstances change, be re-assigned to other work.

Although Bosch insisted onequipping each IVS 200 with its ownproven design of load/unload feedconveyor, so any maintenancerequirement could then be dealt with in-house, Yamazaki Mazak UK took on thecomplete turnkey responsibility.

FOOLPROOF FIXTURINGThis turnkey responsibility included thedesign of the pneumatically-operated‘foolproof’ fixturing that grips each ofthe three sizes of stator assembly as theyare loaded onto the conveyor fromcustom-made pallets prior to machining.It also included, in co-operation withtooling supplier Sandvik Coromant, thedesign of the twin-head tooling thatcompletes the ‘interrupted cut’ closetolerance machining of the two opposedfaces of the segmented steel section in asingle operation.

This twin-head tooling is re-tippedoff-line, with replacement toolinginstalled in a 0.17 second/step indexingdrum turret. Tooling is measured on themachine, with the tool data registeredand the tool offsets adjustedautomatically courtesy of the IVS 200’s

integral ‘Tool Eye’ system. The x and z axes motion of the IVS

200 spindle, which in this application isequipped with an expanding mandrel,are used for both loading and unloadingof each stator assembly. This eliminatesthe need for a gantry robot and reducesthe floor space required. A Renishawprobe is used to determine the exactposition of the stator assembly prior tomachining. This ensures that an equalamount of material is removed fromeach face, so the symmetry of thecomponent is maintained. X-axis travelof the IVS 200, the smallest model in therange, is 320 mm plus 560 mm stroke tothe conveyor and z-axis travel is 280 mm,with rapid traverse rates of 110 m/minand 60 m/min respectively.

The IVS 200’s 35 hp/7,000 rpmspindle can, if required, turn materialwith hardness greater than 50 HRc.However, with the annual output of thisnew design of alternator measured inmillions, the Bosch focus on consistentquality means priorities in thisapplication are the fastest possible cycletime, machine accuracy and consistentperformance, and overall systemreliability.■■

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TURNING

Turnkey turningAn eight-machine

installation at Bosch,

Wales comprising

identical Mazak

inverted spindle VTLs

is producing millions of the

very latest high efficiency

alternators. Machinery reports

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Norfolk-based Mussett Engineering hasslashed cycle times by transferringparts from twin-spindle, twin-turretlathes to its two Deco 20a automaticsliding-head CNC lathes from Tornos.

“I recall one part, a regulator for apressure gauge valve, which previouslytook 6 minutes 35 seconds on a twinturret, twin head lathe that wassubsequently reduced to 1 minute 45seconds on a Deco 20a,” says managingdirector and founder, Gordon Mussett.“There are many more examples wherecycle times have been at least halved,with many operations reduced to justone.”

Mussett Engineering, located 10miles south east of Norwich, claims tobe the largest sub-contract engineeringfacility in the East of England, boastinga workforce of over 100 and an array ofsome 50 CNC machine tools at its33,000 ft2 facility.

Currently the company isusing its Deco machines tomanufacture parts round-the-clock for a leadingproducer of writingimplements.

Although in recent yearsthe company has tended tospecialise in the manufacture ofcomplex parts in batches of 10-100 for the aerospace,automotive, oil, petrochemicaland compressor sectors, somecontracts still call for batches ofup to 20,000 components. Forthis reason Mussett Engineeringcan keep its two 10-axis Deco20a sliding-head autos busy 24hours a day.

“If we get our bar preparation right,these machines have no problemholding micron tolerances time-after-time,” Mr Mussett adds.

Deco sliding-heads slash cycle timesand hold microns

Turret or platen?

The 45° slant bed Dugard Eagle 100lathe can be specified with a 10-toolturret or six-tool platen arrangement.Both configurations are set on thesame heavy base casting and feature amassive ribbed headstock andprecision linear ways providing a swingof 470 mm diameter and a 290 mmcutting length with 6 inch chuck and a52 mm bar capacity.

On both machine types, spindlespeed is 6,000 rpm and rapid traverseis 30 m/min on linear guideways.

A wide range of options areavailable to the machine specification,and the user has a choice of controlsystems from Fanuc, Siemens or aSyntec PC-based unit.

CNC replaces camThe replacement of cam-driven turningwith high technology Citizen CNC mill-turning machines has given John Elliot,the 83-year-old managing director ofQuality Couplings, a new lease of life.“The new machines have transformedthe company,” he says, “giving mecompletely renewed interest – youcould say I’ve developed a totally newoutlook on life!” Following theinstallation of two Citizen C-SeriesCNC sliding-head automatic lathes MrElliot reflects: “One immediate benefitof CNC technology is that we knowexactly where we are with production,quality, delivery and price, and thecompany is already benefiting fromreduced cost of production per part asthe new machines are run unmannedat night.” Twelve months ago, thecompany was facing the spectre of afuture lack of skills for its bread-winning, but ageing, cam-drivenmachine-based turning operation asfour key autosetters (with 75 years’service between them) looked forwardto retirement. Mr Elliott decided in2005 to buy the two Citizen C-Seriesmachines (NC Engineering), with theseinstalled in a refurbished factory unitjust four units away from the cammachine shop. NC Engineeringretrained autosetter Dave Reynolds,while 26-year-old CNC setter/operatorPaul Holliman was recruited to run thenew Citizen C16-VII and C32-VIII. BothCitizen C-Series machines installed atQuality Couplings have main and sub-spindles with two-gang tool slidesenabling simultaneous machining withthree tools. The C32-VIII has an 8,000 rpm main and 7,000 rpm sub-spindle with 14 tools and eight driventools powered by 1 kW motors. TheC16-VII has 18 tools plus eight drivenby 1 kW motors.

Boss bar feeds handlehexagons for hydraulics firmManufacturer of high pressure hydraulic parts Jade Adaptors of Hounslow,Middlesex, has installed IEMCA Boss 21 bar feeders from Kitagawa on its CNClathes.

The company manufactures around 5,000 varieties of adaptor and with somecustomers requiring quantities of more than one million parts a year.

“Around 98 per cent of the adaptors we manufacture contain a hexagonalfeature and the most popular size measures 32 mm across the flats, so itdoesn’t fit into standard 32 mm bar capacity machines,” explains proprietorDave Reynolds. “Once we had installed the new CNC lathes we then needed toreplace the bar feeders. The ones we already had were not able to handle thisvolume of accurate bar cutting, especially at the high spindle speeds requiredby the DMG Sprint 32 machines.

“The hexagonal profile demanded a much greater level of support toeliminate vibration and obtain the surface finish required on the part. The Boss21 feeders exactly met our requirements.”

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Both the GMX 200S and 250S linearmill-turn machines from DMG can bespecified for even faster and easiershopfloor programming.

The claim for the new controls is thata reduction of up to 70 per cent inprogramming times can be achieved, incomparison to DIN. This introductionmakes mill-turn programming as easyand reliable as that for a universallathe, says the company.

When teamed with ShopTurn onSiemens 840D solutionline, the GMX200S is fully equipped for graphic

programming, simple cycle selectionand uninterrupted programmemonitoring on the shopfloor. It alsoprovides 3D workpiece simulation forall turning and milling operationsextending to the b-axis contour.

This development turns the GMX200S linear into a highly cost-effectivemachine for serial production as well asa flexible multi-purpose centre forsmaller batches and jobbing work withno limit on geometric complexity.

The GMX 250 linear with its TurnPlussystem on the Heidenhain Plus iT

controller builds on this flexibility byproviding dual channel control for theshopfloor. It allows the milling/turningspindle and the turret to beprogrammed with simple dialogue via amenu-based interface.

Features include multi-channel slidedisplay during automatic operation anda detailed machining time readoutgiving main and idle time.

Mill-turns programmedat shopfloor with ease

Mori Seiki’s Adaptive Balancer supportsbetter high precision turning of out-of-balance parts. Until now it was notpossible to increase spindle speedwhen machining such items. Mori Seikisays its Adaptive Balancer:● Works for a wide range of unbalanceamounts ● Executes a balancing cycle whileprograms are running ● Balance adjustment amount is 36 gm● Makes balance adjustments in 5 – 10 seconds

● Controls vibration automatically ● Allows spindle speed to be increasedeven during machining of workpieces with eccentric parts, achieving high-precision machining.

This is how it works.Two rings arelayered inside the system. These ringsboth have eccentric weights embeddedin them, but since the weights areplaced directly opposite each other, thebalancer is kept neutral. When thespindle rotates at high speed, it vibratesif the workpiece has an eccentric part.

When this happens, power is sent tothe electromagnetic coil inside thestator, creating a magnetic field. Thiscauses the permanent magnets (and therings) to move.

The position of the weights insidethe moving rings creates imbalance inthe balancer. If the unbalanced part ofthe balancer is placed exactly oppositethe unbalanced part of the workpiece,the two forces will neutralize eachother, achieving rotation with novibration.

Latest turning development is far from eccentric

Tornos developmentsTo improve the capability of the TornosMultiAlpha 8x20 and 6x32 machineswith their powered spindles andcomplex reverse face machining,additional units are being fitted to thenew machines with immediate effect.The first of the innovations is the y-axis on the slide-rest, the second atransverse drilling unit that can befitted in any position without problem.This equipment can be retrofitted toexisting MultiDeco units as well as thenew MultiAlpha 8x20 and 6x32. AndTornos’ Deco Sigma 8 (previously Deco8sp) now incorporates a motorised unitfor live rotary tools and a workpiececonveyor belt to deliver additionalproductivity options for customers.

The new motorised unit enables theuser to install a front-mounted and arear-mounted live rotary tool forsimultaneous main and counter-spindle operations, respectively. Thisallows customers to undertake drilling,face milling on or off axis andtangential milling on the diameter.Being researched are polygon cutting,thread whirling and thread milling.Workpieces can be machined on frontand rear faces within compactdimensions while retaining every toolposition.

� Enter 210 atwww.machinery.co.uk/enquiry

Using Star then.

“Turnover up by 50%.

Headcount down by 50%”

For more information call. 01332 86 44 55 or email. sales@stargb.net | www.stargb.net

Star Micronics GB Limited, Chapel Street, Melbourne Derbyshire DE73 8JF

THE NAME IN SLIDING-HEADSTOCK TECHNOLOGY

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