Lambert fits Schmitt AEMS into Bryant grinder

Lambert recently won an order to rebuild a Bryant grinding machine for Revolvo, a midlands-based manufacturer of large and split bearings.

The machine has been installed at Revolvo's new premises in Dudley.

The high accuracy and repeatability demanded on a rebuilt Bryant grinding machine required an acoustic emission monitoring gap and crash control system from Schmitt Europe.

The high accuracy and repeatability demanded from the machine meant that Lambert chose to incorporate an AEMS (Acoustic Emission Monitoring System) gap and crash control system from Coventry-based Schmitt Europe.

The Bryant LL3 machine was upgraded with CNC control and new software developed in conjunction with Revolvo.

The grinder is capable of outside diameter (OD), inside diameter (ID) and track and lip (Vector) grinding of roller bearings from 50 to 450mm diameter.

The machine has a point wheel dresser unit as standard and has also been retrofitted with a custom-made radius dressing attachment capable of generating gothic-arch wheel profiles.

The machine was originally fitted with a spindle load meter, but retro-fitting with the Schmitt AEMS means that a slide-tube type acoustic sensor mounted inside the grinding spindle can now detect the grinding wheel touching the workpiece or diamond dresser within one millisecond.

This data is sent back via Schmitt's SB-4500 series electronics to the machine control.

The AEMS allows rapid grinding wheel in-feed right up to the point of initial contact with the part, saving considerable air grinding time (non-cutting time) and therefore reducing overall cycle times.

The Schmitt controller also gives a graphical output of noise levels during the grind, so the operator can see what is happening throughout the process in a user-friendly format.

The AEMS can monitor and safeguard against crash conditions occurring on the machine by sensing heavy contact between the abrasive wheel and bearing surface, or other part of the machine.

AE monitoring has also become an integral component in the dressing of abrasive wheels, especially CBN, where it is essential to remove as little material as possible.

The wheel profile can be plotted on screen during a dress, giving a picture of what is occurring on the wheel surface.

The slide-tube acoustic sensor uses non-contact technology and is telescopic to facilitate installation.

It sits inside a bore within a grinding-machine spindle or rotary diamond dresser.

This configuration allows the acoustic sensor to spin with the spindle and means it is in close proximity to the grinding event, giving a clear and uninterrupted signal.

Studer offers Kronos S 250 CNC centreless grinder

Studer has introduced the Kronos S 250 CNC centreless grinder machine concept.

The maximum diameter of the grinding wheel was enlarged to 400-450mm and, as a result, a 30 per cent lifetime increase was achieved.

The design of the cross-slide unit located on both the grinding wheel and regulating wheel side, combining dynamic digital drives and a high-precision ballscrew unit, enables the machine to operate only from four CNC axes.

This design provides the same functionality and flexibility as a six-axis machine.

The Kronos S 250 is designed for in-feed and through-feed grinding, using both conventional and CBN grinding wheels with a diameter range of 1.5mm to 35mm and an in-feed width of up to 245mm.

The utilisation of high-performance grinding wheel spindles and maintenance-free hybrid roller bearings allows the use of CBN grinding wheels with a peripheral speed up to 150m/s.

Another highlight of this machine is the special dressing system for the grinding and regulating wheels by means of four CNC axes in the centre on the workpiece level.

For the grinding wheel dressing, there are optionally stationary or rotating dressers available, which can quickly be changed.

The stationary grinding gap allows the use of low-cost automation equipment, which does not require any follow-up axis.

An integrated handling system with an interface for external transport and palletising devices can be offered as standard.

The compact design of the machine results from the integration of the control cabinet directly fixed onto the machine bed.

This allows users to considerably reduce setup and commissioning time.

The full-size housing of the machine complies with strict environmental requirements, so that various coolant types, such as emulsions and grinding oil, can be used.

Widely opening sliding doors provide access to the grinding centre.

This machine enables the well-directed grinding of diameter and front face in only one operation by using a six-degree angled spindle unit.

Oscillating grinding with a distance of +/-50mm is a further possibility for the centreless machining of extremely hard materials.

Studer to exhibit grinding machines at EMO 2009

Studer is to showcase advanced grinding machines at EMO 2009, which will take place in Milan on 5-10 October.

According to the company, which will be found in Hall 6, Stand G02, the S33 universal cylindrical grinding machine has proven itself for both single-part and large series-production runs.

Now, even more workpiece geometries can be ground in a single clamping.

This development of the tried-and-tested S33 brings important advantages for customers in tool making, job shops and the supply industry.

It is made possible by a new grinding head with two motor spindles for external grinding and an internal grinding unit.

Three grinding wheels ensure that the workpiece can be machined even more individually and quickly.

The S33 is now available with CNC control and an integrated PC.

This enables the use of the new Studerwin operator interface.

The Studergrind programming software modules can now be installed directly on the control system.

The S33 features: a unique arrangement of the motor spindles; simple changeover from grinding between centres to live spindle grinding; a swivelling machine table; an optional C axis for form and thread grinding; a Granitan machine bed; and a selection of options and accessories.

The S22 is the production platform for the individual grinding solution.

The customer's workpiece is the focal point.

Any workpiece can be machined on the S22 using a variety of technologies, such as conventional cylindrical grinding in the production environment, form and thread grinding, high-speed grinding (HSG) with cutting speeds between 80m/s and 140m/s or heavy-duty applications with 160mm-wide grinding wheels.

The X and Z axis are designed as cross slides.

The workpiece table is permanently bolted to the machine and the machine bed is made of Granitan.

The large distance between the guideways and the sturdy machine base ensure excellent stability of this machine concept.

Highly dynamic axis drives, high-quality Studer guideway systems, short reaction times and optimised travel provide the basis for high dynamics and precision.

Pre-tensioned hydrostatics with linear motor or anti-friction guideways with ball-type linear drives are available in the X cross slide.

Available in the Z longitudinal slide are hydrostatics with linear motors or guides with patented surface structures (ribbed structures) and ball-type linear drives.

Thanks to the modular design, the S22 can be configured with almost all existing subassemblies (workhead, wheelhead, tailstock, measuring system and dressing, for instance).

The broad selection is intended to meet every possible requirement: chuck or universal workhead; standard or high-precision C axis (position and speed controlled for form and thread grinding); belt or motor spindle wheelhead; standard, synchronous or fine grinding tailstock; or dressing from the rear with a variety of devices.

An integrated system for measuring during the grinding process, re-measurement, recording, evaluation and trend correction guarantees comprehensive quality control.

For high-speed grinding, a B axis is available with two grinding spindles in the versions left/left or right/left for 400 wheels in the cutting speed range between 80m/s and 140m/s.

Heavy-duty applications with a 160mm-wide grinding wheel are also possible.

The CT960, meanwhile, is said to be the all-rounder for internal and radius grinding.

The high-end universal internal cylindrical grinding machine, with a B-axis swivelling to 91 degrees and four spindle turrets, is suitable for general grinding tasks and particularly for grinding complex workpieces from very hard materials (tungsten carbide, ceramic or sapphire).

The optimal stability and rigidity of the machine enable the finish grinding of workpieces in a polished surface quality.

In the case of dies with open geometries, radii and tapers can be ground with the interpolating B axis.

For dies and moulds with a closed geometry, the traditional method of path contour grinding is used.

Thanks to the HMI-SimCT programming and simulation software, programming and setup times for complex workpieces can be reduced to a minimum.

The grinding process can be simulated and optimised before machining on the machine control or offline on an external PC.

In addition to the four grinding spindles, a measuring probe can also be used for measuring and positioning tasks.

The hydraulically swivelling dressing spindle, which is equipped with an NCC diamond disc, enables the precise dressing of ceramic-bonded diamond grinding wheels.

This technology guarantees that the wheel radius always remains constant during the fine grinding process.

For grinding high-precision threads, such as for thread ring gauges, two of the four grinding spindles can be set to the pitch angle by means of two independent, manually activated swivel axes.

For the internal grinding of thread ring gauges, the CT960 is equipped with three dressing units: one diamond dressing roll with a multi-tooth profile (swivelled at pitch angle), two PCD dressing plates for a single-tooth profile and two multi-point diamonds for diameter and straight dressing.

The CT450L, meanwhile, is described as the optimal machine for low costs per part.

This entry model represents a good-value internal grinding solution with a broad application range; it is used for general internal grinding applications, grinding spring collets or for machining brittle materials.

It is capable of simple grinding tasks such as bores, surfaces and tapers through to complex contours and it has a very compact design and a small footprint.

The setup ergonomics, part loading and measurement are exemplary, thanks to the special machine concept of fixed grinding spindles and moveable workhead on a generously dimensioned cross slide.

The special features also include the linear spindle arrangement and the use of one or two belt spindles with speeds of 28,000rev/min to 60,000rev/min.

The C450, the practical machine for specific grinding solutions, offers even further expansion options in comparison to the C450L; the grinding spindle configuration and the number of grinding spindles can be optimally designed to meet all customer requirements.

A cost-effective solution for automated grinding can be achieved with the optional, fully integrated handling for loading and unloading.

Threaded nuts can also be ground using the optional C axis.