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Motion co-ordinators bring new life to old tools

Edited by the Engineeringtalk editorial team Jan 16, 2004

Control Techniques has pioneered a motor, drive and motion control system which provides substantial benefits to the machine tool sector.

Control Techniques has pioneered a motor, drive and motion control system which provides substantial benefits to the machine tool sector.

"The exceptional performance provided by Trio motion co-ordinators equipped with SLM daughterboards in standard motion control applications can now also be utilised as a very flexible computer numerical controller", said Bill Drury, Executive VP Technology of Control Techniques.

Following a long history of close collaboration between the two companies, Control Techniques already had an excellent understanding of the capabilities of the latest range of motion control products from Trio.

Control Techniques, too, has a significant presence in the CNC machine tool industry, supplying a range of drive, control and motor systems to many of the major manufacturers.

The introduction of SLM technology offered new opportunities to supply systems with enhanced precision of control and much lower build costs through reduced wiring complexity.

SLM technology was originally developed for use with M'Ax and MultiAx servo drives to provide very high, "at source", feedback resolution of over 8.3 million points per turn, 50ns synchronisation between any axis, local intelligence in the motor, up to 50% less wiring, and elimination of the +10V analogue reference signal.

The company announced a policy of close partnerships with multi-axis motion control manufacturers from 1998.

Trio Motion Technology has been an active participant in this partnership, producing an SLM daughterboard for use with its own range of motion co-ordinators.

The Trio MC224/SLM offers 125ms position loop control regardless of the number of axes in the system.

On top of the increased performance, one of the aims of the partnership is to provide "plug and play" capability to a servo system.

Drury commented: "It has been seen in the field that the intelligent drive setup provided by Trio's MotionPerfect software is one of the simplest servo-commissioning systems in the industry".

The combination provided the spur to offer an enhanced system to CNC machine tool builders which would also offer substantial advantages when retrofitted to older machines.

The Control Techniques Research and Development Department retrofitted a conventional CNC machining centre using MultiAx and an MC224 motion co-ordinator.

Accuracy of table movement is assessed using a Renishaw Ballbar system, which permits the user to capture data to a computer for detailed analysis.

The whole procedure, including initial setup, takes about 10min of machine time.

The high resolution feedback combined with full digital interface to eliminate any delays, synchronisation jitter and offsets leads to high dynamic and static stiffness, enabling the system to provide better accuracy and repeatability.

Early tests with a variety of drive/motor combinations revealed that under 10um circularity error at speeds in excess of 3m/s can be achieved with virtually no speed reversal spikes at the four points where the table drive motors reverse.

Machine tool operators are, of course, familiar with the potential for error which derives from the mechanical and electronic characteristics of the machine, and will take these effects into consideration when programming each component.

Further, the package will be of considerable interest to those who wish to upgrade the performance of their existing CNC machines.

"The ease of programming of the Trio motion co-ordinator allows the measured data to be used to compensate for the mechanical errors caused by wear and tear", said Drury.

"The installation of a Control Techniques' SLM system means that older machines can be given a new lease of useful life at a relatively low cost, and users will gain from the reliability and ease of use of the Trio controller".