Design engineers in the precision automation market often put different things at the top of their requirement lists than their colleagues in the instrumentation sector.
Robustness may trump minimum dimensions and dynamic performance to achieve higher throughput which goes hand in hand with 24/7 reliability. Flexible network protocols, such as Ethercat that allows for real-time multi-axis synchronized motion and the capability of synchronizing with external events, are a plus when it comes to integrating the precision positioning equipment with lasers, machine vision, dispensers, etc.
XYZ configuration of two V-417 Linear Motor Stages in XY configuration and one L-412 ball-screw driven linear stage as the vertical axis.
The high dynamics and low maintenance requirements are met by linear motors – low inertia, no friction, no wear. High resolution and accuracy is provided by a wide range of linear encoder options – absolute encoders, for example, save time and add functional safety because they render homing procedures obsolete and avoid run-away situations caused by incremental encoder signal transmission issues. Modern linear encoders can measure motion in increments smaller than one nanometer.
For high force applications, ball-screws with robust servo motors and the ability to run directly on 110/240 volts AC servo drives are available. The ability for the end user to lubricate the ball screw rails without dismantling the stages is a great advantage.
Machine builders in the laser industry also need such positioning stages to offer good resistance to debris ingress and tolerance to hot particulates, so the linear stages have side sealing strips, air purge connections, and hard covers. As the size and mass of the manufactured parts may be challenging, the system components used need to be highly precise, stiff, robust, and offer reliable performance. Industrial motor connectors which are easy to handle and adjust, standard high flex cables, and the ability for the end user to lubricate the ball screw without dismantling the stages and other features often requested.
Design engineers who require ease of installation appreciate the machined reference edge on the new generation of linear stages for easy placement and alignment on their machine base. Standard cable management options and flexible motor cable exits are further advantages. Other important requirements for the linear stage manufacturer are the capability to provide metrology data, error correction mapping or aligned XY or XYZ multi-axis combinations.
EtherCat motion controller Synchronized Motion, Position - Event - Generator (PEG)
Since G-code (Geometric Code) and M-code (Machine Code) languages are the current standard for CNC machining and CAD/CAM systems also produce G&M-codes – it is beneficial to use precision motion controllers that understand commands in these languages, when looking into laser machining applications.
EtherCAT®-based motion controllers such as the ACS distributed architecture easily handle multi-axis synchronized motion applications and G code support. They also provide PEG (Position Event Generator) functionality, to precisely synchronize laser control with motion and other specific motion-related commands for tool and offset compensation commands, and look-ahead algorithms for the processing of segments.
