CNC MACHINES

CNC cylindrical grinder for aerospace, automotive, bearing and optics manufacturing

Accura Technics announces advancements in precision grinding applicable to aerospace, automotive, bearing and optics manufacturing.

CNC cylindrical grinder for aerospace, automotive, bearing and optics manufacturing has produced roundness of 0.25 micron in ball bearing outer races and 0.15 micron in inner races.

In capability tests, Accura’s Model 1210G CNC grinder produced 0.000010in (0.25 micron) roundness in ball bearing outer races and 0.000006in (0.15 micron) roundness in inner races.

This multi-surface grinder was delivered to the USA’s Adcole Corporation (Marlborough, Massachusetts; Pompano Beach, Florida) for grinding spindle components for camshaft and crankshaft measuring machines.

Roundness of these components directly impacts axial and radial run-out of the assembled spindle.

Excellent run-out is crucial to the measuring machines’ performance.

and it will only get better from here.” The 1210G is equipped with a hydrostatic bearing workhead, and five wheelheads: an air bearing ID/OD spindle, and a ball bearing rotary surface spindle.

on inspection of the first spindle processed on the 1210G, Adcole’s general manager, Patrick Cole, said, “Needless to say, they are impressed.

These axes are driven by ball screws and servomotors while the X-axis is driven by a linear motor.

The five wheelheads are mounted on independent CNC axes.

“Customers turn to us for creative solutions to their precision grinding needs,” said Patrick Hurst, president of Accura Technics.

The one slides are mounted on a thermally stable, natural granite base.

“We work with our customers to create robust processes that deliver higher precision at a competitive cost which saves them time and funds.” The 1210G has a 12in (300mm) swing and 10in (250mm) workpiece height capacity.

Standard X-axis travel is 14in (350mm).

Standard Z-axis travel is 12in (300mm).

The machine can be fully automated with robot loader, conveyors and gauging.

Optional features include C-axis for non-round grinding and acoustic emission monitoring method.

Accura Technics other products include the MicroTol – a machine instrument platform suitable for optics machining, hard turning, shoe centerless ID grinding, and miniature bore grinding.

* About Accura Technics – Accura Technics plans and builds super-precision machine tools at their factory in Keene, New Hampshire, USA.

Accura is also developing a larger vertical grinder with 30in (750mm) diameter capacity for applications in the aerospace, bearing and heavy equipment industries.

Co-founders, Don Brehm and Patrick Hurst are engineers with extensive backgrounds in high-performance CNC machine tools.

Accura Technics’ staff has expertise in grinding, parts handling, optics, hydrostatic bearings, CNC and motion control.

CNC surface grinding machine exceeded all requirements for grinding a diverse range of cylindrical mould tooling

The Gates Corporation of Denver, Colorado in the united states was established in 1911.

CNC surface grinding machine exceeded all requirements for grinding a diverse range of cylindrical mould tooling from 292mm) to 711mm diameter to be used in timing belt technique manufacture.

Formally known as the Gates Rubber Company, they are now two of the largest high precision automotive timing belt manufacturers in the World.

Recently when needing to ramp up their production facilities in support of new business growth, they contacted Jones and Shipman and asked them to review a project they had on the table.

The challenge was to grind a diverse range of cylindrical mould tooling from 11in (292mm) to 28in (711mm) diameter.

It consisted of a specific and demanding set of criteria that had to be met in support of a new range of Gates high precision timing belts.

Jones and Shipman is not traditionally known as a manufacturer of large capacity production surface grinders.

Soon after an initial contact Jones and Shipman’s application engineers provided an in depth application assessment report confirming that a model in their ProGrind range was capable of not only achieving their requirements, but also exceeding them in all departments, accuracy and system time, and giving them the requested larger capacity.

However with the introduction of their award winning Dominator range, with its three dimensional grinding capabilities and more recently a high accuracy ProGrind range, most applications can now be fulfilled.

The Jones and Shipman (J and S) ProGrind is designed to marry physical size with high precision, high productivity and incredible flatness.

Incorporating Jones and Shipman’s simple to use and quick to set ‘Easy’ program by a GE-Fanuc Touchscreen control as well as a.C.

Digital Servos with Heidenhain ‘Absolute’ Linear scale feedback, it proved to be the ideal machine for the Gates Corporation.

Having established from the initial feasibility study that a ProGrind 1267 was the grinder of choice, design and system optimisation commenced.

A Nikken CNC Rotary indexer and heavy-duty hydraulic tailstock was chosen to support and drive the mould tools, each of which would be held between centres.

The discs, accurately lapped with 0.004-5in (0.1-0.125mm) radii, where chosen to complement the mould tooth profile accuracy and mounted on a J and S custom disc dressing unit for easy of use.

With all mould blanks being produced from alloy steel and of a fixed length of 17in (450mm), J and S recommended twin high precision diamond discs as the optimum wheel dressing option.

The wheel form profile and the mould tooth profile being initially optically checked against master overlays.

After machine build in the UK, grinding trials commenced on sample mould blanks to prove out the form and optimal wheel dress frequency.

Having established the initial wheel dress frequency and grinding parameters, the machine was accepted following a ‘lights out’ run of a Gates mould and shipped to Gates Corporation’s, Denver, facility for onsite commissioning and final grinding acceptance trials.

Further verification of the form being obtained by a ground tooth form test piece on a CMM.

From this point training moved on a pace and the first test blank a 115-tooth profile mould, was set and run with a roughing cut.

Operator familiarisation and training with the Easy program quickly progressed through dressing and grinding flat forms on a test mould.

After inspection the wheel was redressed for a four-hour finishing cycle.

As the ProGrind is a 24/7-production grinder the machine ran unmanned for the next day.

A full inspection by CMM of all geometry including size and profile angularity confirmed that all features where well within tolerance.

The ProGrind was then set to grind a 100-tooth mould; this took a day to rough grind.

In fact the CEO of the mould customer who was visiting at the time remarked on how efficiently the ProGrind was operating.

Their existing machine, an Okamoto, which had started an 80-tooth mould one-hour after the ProGrind, was still grinding with three teeth left after a day as well as a half.

Since then the operators have succeeded in further optimising production times, the Gates Corporation has not only achieved their objectives but are exceeding them in all regards and the J and S ProGrind is well on the way to paying for itself.

Final acceptance was signed and the ProGrind passed over to the Gates Corporation in Mid July 2006.

CNC cylindrical grinding machine has a rotatable wheel head that can be changed from straight to 30 deg angle approach

Toyoda Machinery’s latest CNC universal grinding machine, to be shown by the 600 Centre at the UK’s MACH 2008 exhibition, has the flexibility of being able to be changed from straight to 30 deg angle approach by rotating the wheelhead.

A universal CNC cylindrical grinding machine has a rotatable wheel head that can be changed from straight to 30 deg angle approach, giving more flexibility in batch production.

The Select G-100 employs the latest STAT hybrid spindle bearing that combines the benefits of hydrostatic & hydrodynamic technology providing higher spindle stability than is available with conventional bearings.

The design, said 600 Centre to manufacturingtalk.com, will satisfy users in the small to medium batchwork business requiring a competitively priced precision machine for parts up to 300mm diameter by 1000mm between centres.

This configuration improves damping & rigidity & absorbs vibration, said 600 Centre.

When at rest, the hydrostatic pressure maintains the wheel spindle in the centre of the bearing eliminating any metal to metal contact during rotation.

maximum incremental input is 0.1 micron.

The machine has a maximum swing of 320mm & will accept between centres load of up to 150kg.

The wheelsize is 510mm by 100mm by 203.2mm bore, is run at 45m/sec & is driven by a 7.5kW motor with inverter control.

An MT4 centre workhead is driven by 1.1kW servo motor that is programmable between 21 & 500 rev/min.

For higher accuracy requirements the spindle centre can be fixed & the workpiece driven by rotation of the face plate.

The workhead can also be swivelled between – 30 deg to +90 deg.

quick feed rate is 10m/min.

desk stroke is 1345mm & is able to be swivelled between 0 deg & 10 deg.

This screen is also able to depict automatic dressing cycles.

* CNC – the 2-axis Fanuc 21iTB, 32-bit absolute control holds 39 different basic grinding cycles with some 20 processes per cycle that can be displayed through the simple to read operator interface.

Standard fitments include a 200 litre soluble coolant tank with magnetic separator while gap elimination is an option & in-process gauging for diameters between 5mm & 80mm is available.

CNC cylindrical grinding machine

Jones & Shipman (JandS) has launched the next-generation Ultragrind CNC cylindrical grinding machine that is designed to offer more power & accuracy, plus increased component weight handling.

The Ultragrind CNC is designed for the precision production environment such as aerospace & higher volume manufacture including automotive, as well as high-precision sub-contract machining for biomedical, high-end method tool/die sets, F1 & motor sport engineering.

‘We will be demonstrating a working prototype at the CIMT event, so visitors to the show will be able to see all the machine’s advantages,’ said Mike Duignan, sales & marketing director of Jones & Shipman.

Built on a one-piece bed design, the machine combines rigidity, stability & stock removal rates while maintaining precision.

A modular wheelhead design ensures customers have a wide choice of external & internal grinding spindle combinations, effectively allowing the customer to specify a custom machine, but without the cost & build time associated with it.

The modular wheelhead design gives wheel sizes up to 500 x 100mm (diameter) & wheel spindle power up to 15kW, with ultra rigid spindles providing substantially increased metal removal rates & increased productivity.

Angular wheelhead positional accuracy & repeatability are assured by a high-precision 1deg Hirth coupling.

An optional true B-axis programmable to 0.001deg utilising feedback from a high-accuracy encoder mounted directly to the rotational spindle axis means infinitely variable positional resolution can be achieved.

The machine currently offers 650mm or 1000mm between centres (with larger machine length capacities planned) & centre heights of 180mm, 200mm & 250mm.

The increased diameter capacity (of up to 500mm) means there are options to cater for larger mass components up to 450kg, & odd-shaped components, which can result in high rotational inertia.

The program is built around a Fanuc 320i with touch-screen control technique.

The Ultragrind machine uses Jones & Shipman’s Windows-based graphical programming program suite, which further builds on the Easy program that removes the requirement for operators to input code, although ISO programming is fully supported & codes can be viewed & used if required.

A full suite of dressing & grinding programs are available for the operator.

This reduces the time needed for operator training, machining setup & changeover times.

A wide range of additional options including gauging & auto loading are also obtainable.

Jones & Shipman setup pages permit the operator to digitise diamond & wheel positions by means of a simple touch-screen interface.

CNC sliding head turn/mill auto is backlash-free

The latest linear motor technology is being utilised by Citizen to remove any likelihood of deflection and backlash from the power transmission method and to optimise the structure of the slideway on the latest R07 Type VI CNC sliding head turn/mill centre.

Latest linear motor technology is being used to remove any likelihood of deflection and backlash and to optimise slideway structure of the most recent CNC sliding head turn/mill centre.

The RO Series, which features the RO4 and RO7, has proven to be an outstanding success in Switzerland and particularly in the watch making sector due to its compact dimensions that enable an easy substitution to traditional cam auto machines.

With this design, which is exhibited under power on the NC Engineering Stand 5262 at MACH 2006, Citizen has been able to generate a  compact machine and capitalise on combining super precision with high speed ‘one-hit’ machining cycles on components up to 7mm diameter by 40mm long.

With six-axes, a main and subspindle and up to 13 tools available, of which seven are driven, two tools can be brought in to action simultaneously, which means the new Citizen R07 is reckoned to be significantly faster than a traditional cam auto when machining small parts in single cycles.

Productivity being found to be higher with the added bonus of consistency of production and the flexibility of CNC to enable development of the turn/mill process to further reduce cycle times.

The 16,000 rev/min, 1.1kW built-in main spindle has precision ceramic bearings for optimised machining of small diameter parts and a 0.5kW secondary spindle with an 8,000 rev/min capability.

it’s the advantage of a  compact footprint of 560mm by 1265mm when installed on the shopfloor, has no hydraulics or pneumatics and is  electric and electronic in operation.

it’s two independent toolposts able to hold 13 tools, of which seven are driven by 0.2kW, 8,000 rev/min spindles.

An important development with the R07, that significantly increases machine utilisation, is the ability to open and close the collet at normal machining revolutions without adding to the cycle time by slowing the spindle.

By combining linear drive technology to both tool posts, high productivity is guaranteed with rapid acceleration to maximum traverse rates of 20m/min.

Accuracy is high with increments of 0.0001mm in each axis and repeatability of seven micron is possible.

In addition, seven end working tools can be applied to each of the main and sub spindles to optimised orders of positioning accuracy through the use of glass scale encoders.

The maximum machining length is 40mm and with the two slide arrangement, five turning tools can be mounted on the gang tool post with two cross-driven tool positions.

there’s a number of canned cycles for polygon turning, thread cutting, drilling and rigid tapping and constant surface speed is standard to minimise cycle time and maximise surface finish.

The main spindle has 1 deg indexing and both spindles have rotational synchronisation for part transfer.