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Precision Linear Encoders
Linear Encoders based on glass scale technology are by far the most accepted
transducers for machine tool applications. These use a sturdy ruler of glass
outfitted with a highly durable chrome grating, placed in a well protected metal
encapsulation. A reader-head attached to the moving part monitors position and
motion by opto-electronically scanning the pattern on the scale.
Accuracy and Repeatability
Accuracy, repeatability and reliability are the well-proven reasons for ANILAM
offering precision glass scale (PGS) technology transducers.
With the very high precision grating applied, the transducer actually reads what
the operator wants to measure. It effectively counts its position digitally
rather than relying on complicated interpolation of analog signals, typical of
inductive technologies like sliding coils over magnetic 0.5" diameter balls
(i.e. more than 600,000 coarser grating).
The precision of the PGS grating and the rigidity of the metal extrusion ensure
that the same position can be repeated within 1.5 micron (.00006"),
significantly higher accuracy than other technologies. The low expansion
coefficient of glass ensures less sensitivity to temperature fluctuations that
may occur during machining.
The PGS encoders are highly resistant to magnetism and electro-magnetic fields
since it uses glass as the grating bearer and opto-electronics for the reading.
This has shown to be beneficial in the typical workshop where a lot of magnetic
material get all over the linear encoder and where electro-magnetic interference
often is generated by high power consumption machinery.
Contaminant Resistance
ANILAM has offered PGS Linear Encoders for more than 25 years and presented the
first contaminant protected encoder 20 years ago. Since then, protection has
been further improved and extensively proven in field, even in the harshest
environments. This is why ANILAM guarantees the resistance to contaminants of
our Linear Encoders.
Contaminant protection is ensured by the way the encoder is built with the glass
well protected by the extrusion and by ANILAM's exclusive lip seal made from
Nitrile. Nitrile rubber seal has unique mechanical properties that provide the
tight seal. Nitrile effectively resists absorption of shop chemicals making the
seal very enduring.
Also, since ANILAM uses PGS technology, the encoders are non-magnetic and will
not attract any swarf.
Roller-Bearing Technology
As a unique design feature for retrofit applications, ANILAM utilizes roller
bearing guided reader-heads in the RBS- and RBM-type linear encoders.
The advantages of this technique are manyfold. First, it ensures a stable
position of the reader-head while scanning the scale grating, ensuring signal
consistency and accuracy. It dramatically minimizes hysteresis effects when
motion is reversed to the opposite direction, bringing the reversal error to a
minimum. Also, the alignment requirement between extrusion and reader-head
becomes less critical, making installation easier.
All ANILAM readerheads have integrated signal processing electronics, minimizing
signal degradation and resulting in excellent noise resistance.
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