Built in Castle Donington, Derbyshire, by LK Metrology Ltd (www.LKmetrology.com), the high-precision Altera range of co-ordinate measuring machines (CMMs) has been coupled with Renishaw’s REVO-2 scanning system and multi-sensor technology to offer manufacturers a powerful five-axis solution for inspecting the dimensional accuracy and surface finish of components.

A particular design feature of this CMM is the ceramic construction of its beam and spindle, which combines optimal stiffness-to-weight ratio for a high level of responsiveness with mechanical and thermal stability for consistent performance across a diverse range of manufacturing environments.

Offering high measuring speeds, the Altera SCANtek 5 includes a multi-sensor package based on Renishaw’s intuitive MODUS soft-ware for importing data, controlling the CMM, acquiring results and reporting — including GD&T (geometric dimensioning and tolerancing) labelling.

The machine’s high scanning speed boosts measurement throughput and prevents the metrology department from becoming the bottleneck in a factory, while providing a comprehensive awareness of product conformance.

The Altera SCANtek 5 is available with a variety of standard measuring volumes from 800 x 700 x 600mm (8.7.6) to 6,000 x 2,000 x 1,000mm (60.20.10); larger options can also be specified.

The AlteraM models with repeatabilities from 1.5µm are being marketed alongside an AlteraSL range offering repeatabilities from 0.7µm. Moreover, these machines are offered with a 10-year accuracy guarantee.

Ready for operation as soon as they arrive in the inspection room or on the shopfloor, these five-axis CMMs are designed to make it easier for users to win new work, while helping to bring products to market faster.

LK Metrology says that three-axis measuring solutions are often unable to measure some complex features, which require the constant acceleration and deceleration of large moving elements of the CMM, whereas the rotations of the lightweight REVO-2 head are synchronised with constant-velocity machine motions when scanning, allowing changes in component geometry to be followed without introducing dynamic errors.

Scanning at up to 500mm/sec without the stylus leaving the surface of the component allows the co-ordinates of up to 4,000 points to be captured ‘on the fly’ every second — a rate of data acquisition far higher than is possible using conventional probing techniques.

It is also possible to include rapid single-touch routines into a measuring cycle. Moreover, the flexibility offered by ‘infinite’ head positioning increases the effective measuring volume by minimising the need for head re-orientations, while allowing highly complex measuring.

Furthermore, exchanging the REVO-2 scanning probe for one of the vision modules increases data collection rates further — and the results can be correlated accurately with those acquired using tactile methods.

Surface finish analysis

By using different tip arrangements and knuckle joints, detailed surface finish analyses can be combined with other CMM measurements in a single operation; even fine bores down to 5mm in diameter can be inspected.

A variety of change racks (up to 1m long) is available for housing sensors, probes and styli, to enable automatic exchange during a measuring sequence.

The MODUS software with its user-configurable interface provides a powerful platform for creating programs, either by teach mode or from a CAD model imported via the usual graphical exchange formats or directly from CATIA, Siemens NX, Parasolid, PTC Creo or Solidworks.

Meanwhile, Wizards in the Windows programming environment that use conversational, graphical and drag-and-drop systems give access to a range of macros and standard scanning routines — such as helical, circular and sweep — to ensure best-practice metrology without the need for specialist programming skills.

Moreover, the native DMIS (Dimensional Measuring Interface Standard) program with drawing geometry, dimensions and tolerance data embedded can be simulated offline to check for potential collisions before an inspection cycle is run on the Altera SCANtek 5.

A comprehensive array of textual and graphical reporting functions is offered, including multi-part inspection for series production and real-time reporting during program execution. Data exchange to third-party applications such as Excel, XML or SQL is also provided, as well as to Q-DAS for statistical process control.

An Altera SCANtek 5 is available in LK’s Castle Donington technology centre for customer demonstrations. Two recently completed tests involved comparisons between five-axis and three-axis scanning of a cylinder head and an aero engine blisk.

In the cylinder head test, 12 valve seats and guides were inspected in 3min 42sec, instead of 29min 13sec; in the case of the blisk — comprising 29 blades — nine sectional, eight longitudinal and two root-profile scans per blade were completed, along with an annulus profile scan, in a total of 2hr 10.5min, compared with 22hr 11min using three-axis scanning.