Superabrasive machining and turning systems deliver massive reductions in product cycle times - in some cases by over 80% - and equally impressive tool cost savings.

Holroyd's new Edgetek range of superabrasive machining andturning systems is providing European industry with a uniqueopportunity to improve competitiveness by delivering massivereductions in product cycle times - in some cases by over 80% -and equally impressive tool cost savings. Designed for use onwide range of standard and ultra hard and exotic materials,including ceramics, nickel, tool steel, Waspalloy, Inconel,Hastelloy, powdered metals and Stellite, the Edgetek machinesdeliver improved quality and part consistency as well as offeringsimplified set-up to optimise manufacturing time. The launch ofthe Edgetek machines further strengthens Holroyd's positionas the world leader in the manufacture of machines and turnkeymanufacturing cells to produce worm and helical gears and helicalscrew rotors.

Manufactured in the UK, at Holroyd's factoryin Rochdale, the multi-axis, CNC controlled machines deployproven high efficiency deep grinding (HEDG) techniques, usingCubic Boron Nitride (CBN) wheels at surface speeds of up to9000m/min.

This enables them to achieve high depths of cut andoptimised metal removal rates far exceeding those of moreconventional machines, such as CNC lathes, milling and machiningcentres and grinders.

In addition to improving product cycletimes, the 'low heat' HEDG system also produces astronger finished component that, when compared to those producedby other techniques such as creep feed grinding, is less likelyto be deformed.

Fundamental to the Edgetek machines superiorlevels of performance and precision, is a unique granite polymerbase and column.

Developed to satisfy the need for extremerigidity and enhanced vibration damping, the polymer basetypically weighs 3 tonnes and has no resonant frequency.

As aresult, it enables higher precision machining to be achieved.Like other unique components in the design, the base reflects themanufacturer's determination to develop a machine range thathas been engineered specifically for high performancesuperabrasive machining.

Holroyd Sales Director, Paul Hannah,explains: 'Unlike other manufacturers, Holroyd is notoffering a range of existing machines that have been adapted.Rather, we are providing a comprehensive product range that hasbeen designed from scratch, incorporating new and sophisticatedtechnology which has been developed specifically withsuperabrasive machining in mind.' 'Every aspect ofHolroyd's Edgetek range has been engineered to provideunsurpassed performance coupled with a level of versatility thatis sure to appeal to the widest possible range of manufacturingoperations.

The massive productivity gains and cost savingsexperienced by those who have made the switch to superabrasivemachining speak for themselves and prove that the technologicaldevelopments pioneered by our machines represent a highlysignificant breakthrough for the future of machining.' Theflexibility of the Holroyd Edgetek design, and the huge varietyof machine types and multi-axis configurations available, enablesthe machines to provide unparalleled levels of precision andproductivity 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 actuationcomponents, 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.

In all of these industries thesimplified set-up of the Holroyd machines ensures that muchproduction time is saved.

At the same time, tooling costs aremuch reduced as the CBN wheels do not suffer from excessivelevels of wear as a result of being subjected to the interruptedcuts experienced on conventional machines, due to their set-uplimitations.

Further emphasising the case for CBN wheels is theremarkable accuracy and metal removal rates that can be achievedby Holroyd Edgetek machines on a wide range of ultra hard andexotic materials and carbon-rich metals.

The large depths of cutthat can be achieved, and the accompanying lower temperature ofHEDG techniques are particularly relevant to aerospacemanufacturing processes, promoting dramatically improvedproductivity, less surface deformation, improved accuracy andbetter surface finish.

Superabrasive technology using CBNgrinding wheels is also a highly successful method of machiningcomponents made from powdered metals popular with automotivemanufacturers.

Although valued for their homogeneous andstress-free composition, materials which have undergone thesintering process are notoriously difficult to machine and aretotally unsuitable for conventional turning.

A combination ofHigh Efficiency Deep Grinding techniques and CBN grinding wheelshas proved extremely successful for the accurate and efficientmachining of powdered metals and has earned Holroyd'sEdgetek superabrasive machining centres growing support amongmanufacturers of components such as gears and sprockets.Providing an ideal complement to the Edgetek machinesmanufacturing flexibility - while at the same time improvingproduction rates, is a unique, Holroyd-designed, 3-dimensionalscanning and measurement system.

Powerful in operation, thesoftware based system measures 500 separate points and comparesthem against the perfect profile while the component is still inthe machine.

Any deviations are corrected automatically beforecompletion of the machine cycle.

If the deviation is greater thana set norm, however, then the system program alerts the operatorto the fact that the wheel may need re-dressing.

Holroyd ismanufacturing Edgetek machines in all types and configurations,3, 4 or 5 axes.

The machines offer state-of-the-art controlfeatures such as Fanuc CNC controls, automated parts handling,customised workholding, cooling systems, programming and processdevelopment and CBN wheel development.

The machines can betailored to suit specific applications and supplied as completeturnkey solutions as part of a manufacturing cell.

They aresupported by a worldwide service network and benefit frommanufacturer developed preventative maintenance plans..

A CNC grinding machine builder has now included cycle programming in its control system, permitting very easy programming for grinding any type of workpiece by the aid of pictogramming.

Experience, market observation and feedback from our customershas encouraged us to develop the existing and proven StuderNCbasic package further. The package includes cycle programming,permitting very easy programming for grinding any type ofworkpiece by the aid of pictogramming. The new version has nowbecome a real desktop platform of grinding technology.

From thisdesktop, all data related to grinding are available forpractically any component.

The new version V5.x of StuderNC alsofeatures the calculation of grinding process data.

This includesmachining data as well as time and cost calculation.

All theother software packages, StProfil, StForm, StPunch and StThreadare related to functions and can be called up as perrequirements.

Philosophy - in our engineering work we made greatefforts to create advantages for our customers.

Our aim was,comparable to StPunch (Software for grinding non-round punches),to integrate the grinding technology in order to guaranteereproducibility, to ensure constant high quality and to reducegrinding times as much as possible.

Data storage should beworkpiece-related and logically clear and straightforward for theuser.

The idea was to preserve the customer's know-how andto call up the respective data later in order to adapt it to thenew machining task.

The process of component machining has beenmade transparent in every detail in order to make use of all theoptimising potential.

This is definitely the only method forincreasing the efficiency continuously: preserving the provenknow-how and to make it accessible to any other user a laterdate.

,Look and feel' This means: the appearance andoperation correspond as much as possible to the commercialWindows applications as they are known in conjunction withMicrosoft products.

High operator ergonomics was one of our maingoals.

The integrated grinding technology improves the efficiencyof the machine considerably.

Experience based on practical workin the range of fine machining by cylindrical grinding haveproved that rather often the operators of grinding machines workwith values resulting from their experience, which isastonishingly far away from the optimum.

So-called machiningtasks which can be defined by our customer's or by our ownspecialists help to produce components in a constantly goodquality and time independently from the operator who carries outthe job.

A machining task defines the behaviour of a certaingrinding tool in a specific material.

By doing so, the coolant,the rigidity of the component, the machinability of the materialand many other factors can be taken into consideration.

Byincreasing the quality of the optimisation of machining tasks,the optimising times can be reduced considerably for new, similarworkpieces.

For the production of individual parts and series,one will always be able to operate with former, highly optimiseddata for the same combination of tool and material.

This willreduce the running-in times to a level corresponding to that ofsame components which are machined repeatedly.

By indicating theexact time of each individual process, those for dressing andtraversing as well as the auxiliary times such as longitudinalpositioning by means of a length positioning, one should obtaininformation about the productivity.

The calculation should giveaccurate information for the quotation.

In addition, thecalculation of costs can go much further than that based merelyon the grinding time for a component.

For instance, toolingexpenses have to be taken into account.

This is extremelyimportant for job planning and for quotations.

* Dressing: Roughdressing cycles to profile, respectively reprofiling grindingwheels - for profiling, new rough dressing cycles are now atdisposal.

Roughing means - similarly as for milling or turning -creating an optimal assignment of cuts in order to remove as muchmaterial as possible in the shortest possible time.

By doing so,the set-up times are reduced to a fraction compared to those ofthe conventional method.

* The advantages - by using StuderNC andthe respective options for profiling and dressing the grindingwheels as well as for thread grinding and grinding non-roundsections of components, the customers gain an extremelysignificant increase of functionality for their universalcylindrical grinding machine.

In the simplest case this meansthat set-up, programming and grind-ing times will be reducedconsiderably.

In other cases, it may even be possible to avoidthe use of special machines, such as thread and cam grindingmachines.

Partially, the same also applies to special clampingfeatures such as eccentric chucks.

From this point of view, theinvestment will certainly be written off in a very short time.

*Range of applications - the range of application of StuderNC isalso intended for the real grinding Professional.

The system iscompletely open and allows changes in every section.

However,this product is useful even for the inexperienced user who,thanks to this application, can operate with littlegrinding-specific know-how.

Also standard Macro's defined inadvance by Studer cover a wide range of components.

In addition,this software is also useful for the job planning, namely forestablishing quotations and process data for the properproduction.

Eliminating the backing pad and tapered flange nut from portable grinding wheel securement results in a lighter unit to ease operator control and comfort and reduce fatigue.

Metabo Corporation, a leading international manufacturer of professional grade portable electric power tools and abrasives for various industrial, construction and welding applications, has introduced the Type 29 Z-Plus grinding wheel that eliminates the need for a backing pad and tapered flange nut. The Type 29 Z-Plus weighs less than half of a typical 4-1/2in grinding wheel. This significantly increases the operator's control and comfort while decreasing fatigue, particularly with small grinders used in tight spaces and at odd angles.

The wheel's slightly concave profile also lessens the grinder's angle of attack, reducing operator fatigue.

The Type 29 Z-Plus, with its aluminum oxide abrasive, is well suited for blending and surface weld removal on steel, stainless steel and aluminum.

The wheel, a refinement of Metabo's Type 29 grinding wheel, can also be used to grind other non-ferrous metals, as well as most plastics and resin or fiberglass-based structural materials.

The Type 29 Z-Plus is available in 4-1/2in or 7in diameter, with a 7/8in arbor or 5/8in-11 hub.

A research project using superabrasive machines has achieved a significant breakthrough in machining superalloys - in terms of reduced cycle times and better surface finish and accuracy.

A research project undertaken by a team at CranfieldUniversity's School Of Industrial and Manufacturing Sciencehas employed Holroyd's superabrasive Edgetek machines toachieve significant breakthroughs when machining Nickel basedsuperalloys; materials which are notoriously difficult to work.The breakthroughs, in terms of reduced cycle times, bettersurface finish and improved accuracy, have been achieved usingthe latest high efficiency deep grinding (HEDG) techniques. Theyare likely to have a profound influence on the way thatsuperalloys are machined in the future within the aerospaceindustry. The Cranfield team, led by Professor David Stephenson,carried out lengthy 'Burn Threshold Studies' on Inconel718 - a superalloy commonly employed for gas turbine components,using Holroyd's 'Edgetek' Superabrasive Machiningprocess.

Manufactured at Holroyd's UK factory in Rochdale,the multi-axis, CNC controlled Edgetek machines deploy provenhigh efficiency deep grinding (HEDG) techniques, using CubicBoron Nitride (CBN) wheels at surface speeds of up to 200m/s.This enables them to achieve high depths of cut and optimisedmetal removal rates far exceeding those of more conventionalmachines, such as CNC lathes, milling and machining centres andgrinders.

An Edgetek machine (a five-axis unit) was specified forthe Cranfield research project due to its ability to machineNickel-based superalloys such as inconel 718, which are extremelydifficult to work.

The ability of these alloys to retain much oftheir strength at elevated temperatures means that wear rate onconventional tooling is rapid, even when cutting at low speeds.In addition, problems such as workpiece burn and poor surfaceintegrity are common, due to the alloys low thermal conductivity.Over the last 30 years developments in creep feed grindingtechniques have addressed some of these problems, notably inachieving higher rates of metal removal, but economic pressuresto reduce manufacturing costs further, and to improveproductivity, still remain.

As a direct result of thesepressures, a growing interest in HEDG (high efficiency deepgrinding) has developed, which can be considered as a combinationof creep feed grinding and high speed grinding, using high wheelspeeds often in excess of 200m/s.

A main area of research hasbeen to attempt to prove a commonly held HEDG theory that veryhigh stock removal rates are associated with low work-piecetemperatures.

Key to this, were the grinding trials carried outat Cranfield University.

The trials were undertaken on blocks ofInconel 718 measuring 40 x 40 x 40mm, using a 'downgrinding' mode and grinding parameters were varied over thefollowing range: depth of cut: 0,05 - 1,5mm, work speed: 0,05 -55mm/s and wheel speed: 50-150m/s.

For each test a series of 15mmwide cuts was taken and resultant forces were measured using athree-axis dynamometer.

Although the results of the trials arenaturally very detailed, the general trend shows a reduction inspecific grinding energy as specific stock removal ratesincrease.

Commenting upon this, Professor Stephenson said:'The thermal modelling results correlate well withexperimental observations of grinding burn.

Modelling indicatesthe potential benefits associated with HEDG, using high workspeeds and large depth of cut to minimise the finished surfacetemperature.

Thermal modelling also highlighted the significantcontribution that CBN abrasives can make to heat removal.'These results, highlighting the large depths of cut andaccompanying lower temperature work-piece characteristic of HEDG,have significant practical relevance in terms of aerospacemanufacturing processes, in that the two promote dramaticallyimproved productivity, less surface deformation, improvedaccuracy and better surface finish.

'We are delighted, butnot surprised by these results,' said Holroyd SalesDirector, Paul Hannah.

'The massive productivity gains andcost savings experienced by those who have made the switch toEdgetek superabrasive machining speak for themselves and provethat the technological developments pioneered by our machinesrepresent a highly significant breakthrough for the future ofmachining.' In addition to its key role in the BurnThreshold Studies, Holroyd's Edgetek machine is also centralto another Cranfield project, 'Ultraflex', which isrunning simultaneously.

'Ultraflex' is a European /automotive industry-funded project, for the development ofinnovative manufacturing technologies for reducing processchains.

Its specific objectives are to develop and to demonstratethe following two processes: * Cost-effective and highproductivity machining process of high-alloy steel beforehardening operation and hardening process.

* Ultra-precision andenvironmentally friendly machining process of high-alloy steelafter hardening operation.

The Edgetek machine is playing a keyrole in developing these processes and in achieving the twoperformance targets for the project: (1) working towards opticalquality, machined surface finish levels of Ra 0.0micron and (2)the ability to rough finish a high alloy steel CVT gearshaft inless than 2 minutes.

The groundbreaking research carried out byCranfield University on both Burn Threshold Studies and projectUltraflex and the positive results obtained, proves conclusivelythe effectiveness of Superabrasive machining on difficult to workmaterials, not only within its 'traditional' sector ofhigh volume production associated with milling machineaccuracies, but also on very close tolerance work with highlevels of surface finish.

However, despite these results, neitherCranfield University nor Holroyd are resting upon their laurels.Holroyd is conducting ongoing technical developments at itsfactory in Rochdale which complement the innovative researchcarried out by Cranfield University, developing further thepotential that exists in this rapidly growing area of machinetool technology.

Stressing the latter point, Holroyd's PaulHannah said: 'Feedback from customers and the results ofdetailed research into superabrasive machining both support theview that this exciting technological breakthrough has massiveimplications for the future of a wide range of machiningoperations.

The dramatic reduction in cycle times and toolingcosts which result from a switch to Holroyd's Edgetek'superabrasive machine tools contribute to significantimprovements in overall productivity for every company usingthem.'.

Cylindrical grinder provides a highly flexible, single-cycle universal solution to the finishing of one-off parts or small batch runs.

Developed to provide a highly flexible, single-cycle universalsolution to the cylindrical grinding of one-off parts or smallbatch runs, the latest Danobat G-41 cylindrical grinding machineis able to accommodate external, internal diameters, faces andtapers. Now marketed through 600 Centre of Shepshed nearLoughborough, the Danobat G-41 Universal 'U' machinecan also be specified as a lower cost 90 (degree) approachconventional cylindrical grinder designated 'S'. Themachine has been developed in order to maximise the potential ofcubic boron nitride (CBN) wheel technology through high orders ofdesign rigidity.

This means high performance, accuracy andrepeatability have been developed into the machine.

When thesefeatures are combined with Danobat's DanOp, DanBop andDanCad software modules, flexibility and operationalfunctionality provide a high performance grinding package forcomponents up to 348 mm diameter by 1,000 mm long.

Built on astabilised pearlitic cast iron base with integrated 'doublebody' table, the machine is compact, stable and very rigid.Table swivel is +9 degree to -2 degree.

The servo driven table isable to swivel between +45 degree and -15 degree and the workheadwill accept components weighing up to 125kg between centres withstepless programmable speed range between 30 and 1,000 revs/min.The indexing universal wheelhead has zero, 30 degree, 90 degreeand 180 degree working positions and the ability to carryexternal, face grinding or internal grinding spindles.

Theuniversal wheelhead has a 7.5kW drive, 45m/sec wheel speed and500mm by 80mm by 203mm external grinding wheel and a facegrinding wheel.

It also has the ability to carry one of a rangeof four internal grinding spindles having up to 30,000 revs/minspeed and the capacity to grind bores up to 160mm diameter.

Withthe option of a 90 degree approach wheelhead, this has a 5.5kW,45m/sec grinding speed and wheel size of 400mm by 63mm by 127mm.Based on Fanuc 210i control system, software development was seenas important to the Danobat specification.

This has resulted inthe DanBop machine control software being classified to be assimple to operate as a manual machine and this is achieved bysimply selecting the type of work required.

It can incorporatefully or semi-automatic cycles and accommodate dressing,measurement and changes to grinding parameters.

The DanOpsoftware module accommodates machine functions with soft keyprogramming for set-up, wheel management, work cycling andproduction management.

DanCad incorporates graphic support directfrom CAD systems to enable programming based on componentgeometry and is able to optimise tasks such as wheel profilecreation and dressing.

Options include gauging, gap eliminationand crash detection devices, steady rests and a range offiltration and coolant systems.

Dynamic balancing, workholdingand a portable handwheel unit are available to help in machineoperation..