CONTROL Techniques ' new M'Ax servo drives are a big step forward in servo technology and have been designed to help the machine builder, cutting set-up times and improving performance.
M'Ax is the first servo to provide 'easy-start', with auto loading of the motor map - virtually plug and go. M'Ax is also extremely compact, using less cubicle space than most servo drives and, using SLM technology, wiring is drastically reduced too. Particularly important for complex installations is the fast synch between drives, with performance unaffected by the number of axes involved and the ultra-fast acceleration compensation.
Youngs Bluecrest Seafood decided to upgrade a packing line for fish fingers, constructing their own system using the M'Ax servo system. Frozen fish fingers are fed across a vibrating deck, which collates them into 50 lines of product. Five packs at a time are indexed into the packing machine, using the registration input to measure the carton distance to the pneumatic stop. This replaces 14 packers. As the fish fingers move down the deck, a servo motor provides a finger lifting and separating action from underneath to prevent them sticking.
Servos then provide indexing into a collating plate, which pushes the blocks of fish fingers into the correct width for the box and a vacuum pick and place unit picks up five carton loads at a time and places them in their boxes. Finally, an acceleration conveyor rapidly clears the boxes ready for the next batch. Previously, this had been a hand-picking line, employing 27 people.
Overall control of the system is from a Control Techniques MC216 modular motion controller, that is expandable to 16 axis control with the addition of daughter boards. With high-speed multi-axis control (1ms per axis), the MC controller is able to perform tasks such as cam indexing and complex acceleration/deceleration profiles and variants are available to cover every conceivable feedback.
Working with M'Ax servo controllers and Unimotors with SLM technology, packages are particularly straightforward to build into a machine because of the simplicity of programming and the reduced number of wiring connections.
SLM technology uses the motor-mounted SinCos encoder and DSP technology which provides very high resolution control. Cabling costs are cut by two thirds and an error-free signal is ensured through a high-speed dedicated bus system.
The Unimotor range of brushless AC servomotors from Control Techniques gives extraordinary torque per unit volume with industry-leading thermal performance. The single-piece integral construction, which gives increased torsional stiffness, also permits accurate and consistent bearing to housing alignment and maintains air-gap concentricity. This arrangement optimises torque output and reduces cogging to less than 1%.
The SL motors feature a module with built-in speed loop electronics and a specially developed encoder interface and is designed to provide highly accurate speed and position control when used in conjunction with the M'Ax range of servo drives.
This speed and position transducer provides a resolution of greater than eight million points per revolution, giving a greatly enhanced performance, with a digital link unaffected by noise.
Further, with intelligence centred on the motor, the update loop response is cut to just 125μs and a staggering axis to axis synchronisation of 50ns.
The reduction in cabling with the SL Unimotor coupled with M'ax servo drive also gives major customer savings. Not only does the package cost less than that of equivalent servos, but the installation time is reduced. With half as many cables to connect, the chance of error is less and the ongoing costs of maintenance are reduced by improved reliability.
The final deciding factor for many users is the 'plug-and-play' connectivity, with an ASIC on the motor sending set-up data to the drive on initial switch-on. Even an inexperienced engineer can complete commissioning in around one minute.