Product category:
Linear Position Sensors
News Release from: ACI (UK) | Subject: Products at MACH
Edited by the Engineeringtalk Editorial
Team on 25 February 2004
Glass linear encoders have clear
advantages
Anilam, a division of measurement and control specialist ACI Europe, will use MACH to reinforce both the accuracy and performance benefits of its glass linear encoder technology.
Anilam will not only be using MACH to illustrate its pioneering position in the development of one- and four-axis DROs, but the complementary display of linear scales will also serve to reinforce both the accuracy and performance benefits of its glass linear encoder technology "Glass precision linear encoders are the most accurate way to cost-effectively measure distance/position in a straight line", comments Managing Director Phil Goulding
"That's why around 90% of machine shops globally - and most OEMs - use this type of optical encoder rather than inductive types".
Anilam was the first company to produce a programmable DRO (a product which took the competition four years to emulate) and one of the first to use contaminant-protected glass scales over 30 years ago.
"There's no argument that glass encoders are more accurate", continues Goulding, "because they have 1270 points of measurement graduations per inch compared with the four points per inch that characterise many other alternative (transducer) types".
Accuracy is, of course, the key denominator when comparing encoders, he says.
"Anilam ensures accuracy by adding the hard chrome graduations - which occur at every 20 microns step - to the glass in a vacuum, then the scale is mounted in a one-piece extrusion using elastic adhesive.
Coupled with the fact that the roller bearing-guided reader heads consistently maintain their position relative to the grating, and the result is predictable and repeatable measuring to +/-5um/m".
This compares, he says, with encoders that are constructed of other materials that, conservatively, even if they can be produced to within 1um of each other means that their inaccuracy over a 1m length could be as much as 80um.
The longevity of glass scales and their suitability for working in the harshest metal-cutting environments are other myths that Anilam will be dispelling at MACH, where it will be showing examples from a comprehensive range of precision glass scale linear encoders having resolutions from 5 to 0.5um, to suit the application.
The use of "smart" technology features has injected unparalleled levels of performance and power into Anilam's DROs - as will be seen with the series W211 (one-/three-axis), W450 (one-/three-axis), W450L (two-/three-axis for lathes), W900 (two-/four-axis) and W900E (EDM-specific) DROs on display.
The developments are headed up by the EverTrack absolute reference system.
This enables the DRO to always know its position in absolute terms.
Available with both the RBS and RBM linear encoder scales, EverTrack always keeps track of the position - even if the power is interrupted - and so eliminates the need for awkward battery back-up solutions.
EverTrack uses a reference index track comprising two sets of marks.
Each set has the same distance between its own marks while the relationship between each set is unique.
Thus by moving across two marks anywhere on the scale, the system will know exactly where it is.
The MACH display being staged by ACI Europe will also feature examples from the Anilam CNC range, as well as Acu-Rite DROs and Millpwr CNC and Quadra-Chek DROs for measuring applications.
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