Product category:
Actuators, motion systems, etc
News Release from: Aerotech | Subject: ADRT high accuracy, direct drive rotary tables
Edited by the Manufacturingtalk Editorial
Team on 01 July 2005
Small rotary stage positions precisely
More flexibility and choice for high speed/high precision angular positioning applications are provided by precision rotary stages for laser machining and wafer inspection.
With the introduction of a new smaller sized model, the Aerotech ADRT range of high accuracy, direct drive rotary tables now offer even more flexibility and choice for high speed/high precision angular positioning applications The new compact but powerful ADRT-100 is built around Aerotech's S-series, brushless, cog-free, direct drive servomotors with high resolution feedback providing 2000 rev/min speed performance with high acceleration and extremely precise positioning characteristics, seriously outperforming conventional worm wheel based rotary stages
This article was originally published on Manufacturingtalk on 11 Jul 2008 at 8.00am (UK)
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Aimed at demanding high throughput applications, such as laser machining and wafer inspection, the new ADRT-100 series has a footprint of just 96mm x 120mm with a 50mm diameter rotating platen and a 13mm aperture for services or product feed-through.
It is available in a choice of two heights, 85mm and 135mm, with an axial load rating of 15kg and continuous torque outputs of 0.4Nm and 1.96Nm respectively.
As with all ADRT rotary tables, the new -100 model is fitted with dual bearings in a choice of standard grade for a cost competitive solution for most high performance applications, or precision grade for superior accuracy, repeatability, wobble and run-out characteristics.
Further reading
Sealed gantry handling system avoids dirt ingress
A sealed version of a linear motor driven, X-Y gantry system is particularly suited to applications such as high throughput laser machining and welding.
Open frame air bearing stage has long life
An open frame air bearing stage provides the specification for through-aperture step and scan positioning and uses preloaded air bearings, direct-drive linear motors and high resolution encoders.
Low profile rotary stage offers high speed
A low profile, high speed, compact rotary stage provides a solution for compact positioning spindle applications and operates at up to 15,000 deg/s.
ADRT rotary stages are available in three other models with nominal footprint dimensions of approximately 150mm2, 200mm2 and 260mm2.
The ADRT-150 range has three height options for continuous torque requirements between 3.6Nm and 11.4Nm with an axial load rating of 30kg; the ADRT-200 offers two heights for 16.9Nm and 24.9Nm torque and a 140kg axial load rating whilst the ADRT-260 series is available in two height options with 30.4 and 44.5Nm torque for a 170kg axial load rating.
Through the range, the maximum speed is 2000 rev/min for the smaller (-100) model and 375 rev/min for the largest (-260).
Positioning resolution depends upon speed requirements, encoder and feedback multiplication with a maximum specification of 18 arc-sec for the -100 model and 12 arc-sec for the -260.
Calibrated accuracy across all models is +/-15 arc-sec for standard grade bearings and +/-5 arc-sec for the precision grade option.
Wobble, axial runout and radial runout ratings are of a similar high order and all measurement plots and calibration charts can be supplied on request.
Accessories and options for the range include a wide choice of encoder and positioning transducers for varying resolution requirements.
Both normally-closed limit switches and hard-stop end of travel limits are available, positioned to exactly suit customers' requirements.
A holding brake is available to prevent stage movement on power-off conditions or under impulse moment load conditions and all units can be specified with an air purge option to prevent the ingress of swarf and debris for machining applications.
A wide choice of electrical interfacing options are available, all supplied with mating connectors.
Mechanical interfacing for the larger ADRT models is aided with vertical 'T' slots allowing the table to be mounted horizontally or for attaching fixtures and tooling.
All table-tops have multiple threaded holes on both rotating and static mounting faces and each model features a clear aperture to allow laser beam delivery, product feed through, slip ring assemblies or other tooling requirements.
ADRT rotary stages utilise Aerotech's S-series brushless, direct-drive servo motors; based upon a slotless stator with no iron laminations eliminating torque ripple and allowing 'cog free' ultra-smooth velocity control comparable to that of a high quality brushed DC motor.
The dual preloaded bearing system and low-inertia, direct drive servomotor is precisely aligned and directly coupled to the table top and rotary encoder assembly; the resulting velocity stability and dynamic performance under unidirectional and bidirectional positioning conditions is of a much higher order when compared to traditional worm driven rotary tables.
High acceleration capability to quickly position the load, exceptional in-position stability and the inherent zero backlash of Aerotech's direct-drive technology combined with longer life and virtually maintenance-free operation is perfectly matched to high precision applications for the ADRT range of rotary stages.
Larger ADRT rotary stages are completely self-contained with motor and encoder feedback connectors integral within the housing keeping the overall footprint to a minimum.
The new compact ADRT-100 model has a 'pigtail' power and feedback connector fitted to keep the footprint extremely small and to allow quick and simple installation.
Like all Aerotech mechanical positioning solutions, ADRT stages are typically used with the comprehensive range of Aerotech motion controllers and servo amplifiers and are supplied as systems, complete with motor power and encoder cables and all performance and calibration related documents including complete interconnection drawings to help integrators with their own system documentation.
In addition, all motor parameter set-up data for the software configuration file is included; system commissioning is straightforward, requiring little more than connecting cables and applying power before programming application software.
These features are built into every Aerotech product ensuring that the true cost of ownership is extremely competitive. Request a free brochure from Aerotech ...
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