Product category:
CMMs (co-ordinate measuring machines) and software
News Release from: LK | Subject: Evolution CMMs
Edited by the Manufacturingtalk Editorial
Team on 06 October 2003
CMMs include continuous contact probing
Latest CMMs offer increased functionality for the measurement of dimensions, positions, curves and free-form surfaces with high density scanning capability.
Manufacturers, especially in the aerospace and power-train automotive sectors, need co-ordinate measuring machines that are compatible with concurrent engineering practices and help to shorten product development time Data collection, usually by taking a single point or series of points with a touch-trigger probe, is now being superseded by continuous contact probing, better known as analogue scanning
This article was originally published on Manufacturingtalk on 14 Jul 2000 at 8.00am (UK)
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At Luton-based Huntleigh Healthcare, the time taken to program a seven year old Mitutoyo co-ordinate measuring machine (CMM) has been halved using CAMIO software
To meet this need, LK has introduced a new range of bridge-type CMMs, called Evolution, designed specifically to provide the optimum mechanical performance for analogue scanning.
Offered with measuring envelopes ranging from 800 x 700 x 600mm to 5000 x 1500 x 1500mm, the machines combine extremely high measuring accuracy with the fast operational speed of a production line-based CMM.
This level of performance, which is usually associated with high cost measuring machines, is available with the LK Evolution at a competitive price, making the scanning revolution affordable to all companies.
Further reading
CMM software applicable to LK and other makes
LK, has introduced a new, advanced suite of programming software for use with its own and other manufacturers' co-ordinate measuring machines.
Complex aerospace CMM programming uses CAD data
Subcontractor Castillion says it would not really be able to handle some of the work it does now without LK CAMIO, a CAD-to-CMM interface which allows solid models to be imported and used
CMM upgrade allows import of solid models
Derbyshire-based co-ordinate measuring machine (CMM) manufacturer, LK, has upgraded the Zeiss CMM at the Heraeus QuartzTech factory, which produces silica quartz ovenware for semiconductor makers.
The innovative design of the new machine was created using computer aided solid modelling and finite element analysis where both the material selection and structure design were finely tuned to maximise stiffness, reduce vibration and provide smoothness of axis motion, all of which are fundamental in providing high accuracy scanning systems.
The construction incorporates an increased cross-section, ceramic design for the bridge and quill.
This material is ideal for a metrology structure, being 330 per cent stiffer than aluminium and only 32 per cent heavier by volume, resulting in high machine acceleration and velocity.
Ceramic also has a thermal expansion coefficient four times lower than aluminium, making the structure highly resilient to thermal change, so maintaining accuracy and performance.
All guideways use LK-designed, high efficiency air bearings which run with a reduced air film for low energy consumption and employ high stiffness friction drives with stainless steel drive belts.
Axis motion is assisted further by a new 'S-curve' profile for the servo motors rather than the traditional trapezoidal velocity / time profile, giving smooth, repeatable axis travel essential in accurate scanning systems.
Finite element analysis, as used by Formula 1 teams to maximise design efficiency, has been employed to optimise the complete machine design, which together with high build quality has prompted LK to offer an industry-leading, 10-year guarantee for the Evolution's dimensional stability.
The overall result is an extremely stiff metrology structure designed to withstand the higher forces generated by continuous contact measurement using high acceleration / deceleration, without sacrificing accuracy or risking machine deterioration over time.
ISO10360-4 scanning test results with the Renishaw SP25 probe give an MPR of 1.9 microns and an MPT of 68 seconds.
Repeatability is as low as 1 micron at scanning speeds in excess of 12 metres per minute.
Data collection rates can be up to 1,000 points per second to provide excellent component form definition and dimensional results.
Maintaining the accuracy over the wide operating temperature range of 10 to 35 degrees Centigrade is achieved by a combination of LK's dynamic temperature compensation and dynamic probe error correction.
The latter provides temperature compensation right to the stylus tip, not just the probe head centre.
LK research shows that a 5 degree Centigrade temperature change for a probe length of 230 mm could add up to 20 microns of error, which would remain uncompensated for in conventional systems.
Calculation of the thermal expansion co-efficient for any probe assembly is automatically generated by LK's CAMIO inspection software, removing the need for any complicated calculation by the user of probe assembly values.
To ensure the new Evolution range is 'future-proof', the controller uses advanced integrated modular technology that allows new hardware support modules to be added, with shortened development time.
Examples of this include laser probing.
To provide a complete, single-source solution, LK's full suite of internally-developed, Windows-based, 3D measuring software is available.
Included are the CAMIO Studio DMIS-based software for measurement using CAD data, and CAMIO Inspect for non- CAD applications.
Recently released in their third versions, both Studio and Inspect offer functionality and a user-interface designed to meet the needs of all skill levels, from novice user to experienced CMM programmer.
To assist non-skilled CMM operators, Launchpad software provides a graphical menu structure detailing component selection, required loading position within the machine and program launching instructions.
Programs can be launched with one-click, eliminating any keyboard operation with fully automatic printing of the report at the end of the inspection.
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