Following an extensive review of their wide range of automated handling machines for the cookware, ceramic and tableware markets, production machine manufacturer CMC Srl has opted for servo-drives and brushless servo motors from Control Techniques.
Since its establishment in 1981, CMC, located in the heart of the Italian ceramic tile production area in and around Sassuolo in northern Italy, has specialised in the design and technical development of innovative production line machines that meet the individual operational requirements of their customers.
Recently, the company reviewed all of their designs, looking for ways to enhance handling, increase throughput and generally improve machine efficiency and performance.
The first step was to reassess all motion controls using conventional induction motors, which formerly produced the movements for all axes under the control of variable-speed drives. The brief was to improve efficiency, dynamic performance and accuracy. Control Techniques recommended brushless servo-motors for the task to ensure high precision positioning and lower energy losses.
To give the best feedback, the drives were fitted with Sin/Cos absolute encoders that store the position of each axis in permanent memory, dispensing with homing set-up procedures which would otherwise be necessary at each start-up.
The ultra-compact Digitax ST servo-drives are used in conjunction with centralised motion controllers and can be connected using either digital or analogue networks, providing the movement control for each axis. Optional plug-in modules are used to interface the servo-drives with dedicated servo networks – typically EtherCAT, Sercos or CANopen. Dedicated I/Os include high-speed ‘freeze’ input, high resolution analogue input and simulated encoder output simplifying the connection of the drive to external controllers.
The encoder input accepts feedback signals, Sin/Cos, Hiperface, Endat and SSI allowing selection of the most suitable feedback for each application.
The Digitax ST range encompasses four models, each with industry-leading features, extremely compact in size and having full compatibility with Control Techniques’ existing range of function and communication modules. It is optimised for servo applications requiring high peak torque, exceptional dynamic response, faster installation and start-up as well as ease of integration. Four product variants make up the range: Base, Indexer, EZ Motion and Digitax ST Plus.
In addition, Digitax ST has a ‘Safe Torque Off’ standard input that disables the power stage of the drive with a high degree of safety, for maintenance purposes. This reduces the cost of meeting compliance with machine safety standards EN 954 Cat.3.
A typical CMC machine is an auxiliary system for use with a press for the production of aluminium pans. The system comprises a series of elements.
A module for de-stacking and distribution of aluminium disc blanks is followed by transport, inspection and oiling of the blanks, which are then aligned and elevated to a take-up station that comprises a pair of straight bars with synchronised movements. A pan take-up and conveyor completes the unit.
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The machine set-up is controlled by a selection of menus from the screen and requires minimal manual intervention. The machine achieves a high production rate of 16 cycles per minute. Access to the press during die-change operations is both easy and safe. The machine is very flexible and easy to adapt to different products and has a very low maintenance requirement. Digitax ST servo-drives control each of the key axes within the machine.
CMC Srl manufactures a wide range of machines, particularly for the ceramic industries. The company is a key supplier/partner for the SACMI Group and has supplied machines for some of Europe’s most prestigious manufacturers of tableware including Villeroy and Boch, Pozzi-Ginori and Tognana.