When Youngs Bluecrest Seafood decided to upgrade a packing line for fish fingers, they opted to ‘do it themselves’ using the M’Ax servo system with SLM Technology from Control Techniques. The result? The removal of a production bottleneck, a saving of some £180,000 per year and an increase in production!

The line takes frozen fish fingers and packs 50 at a time into five cardboard boxes. Previously, this had been a hand-picking line, employing some 27 people. “We looked at the options available to us and realised that we could build a fully automatic machine ourselves for the same cost as buying in a semi-automatic,” says factory engineer, Stuart Baker.

“But it all hinged on the servo system,” he added, “and, after we undertook a technical appraisal, we chose Control Techniques M’Ax with 4-wire SLM, because of its flexibility, ease of programming and greatly reduced wiring.”

The system comprises a Control Techniques MC216 motion controller, with its capability of 16-axis control, eight M’Ax singleaxis servo drives and eight Unimotors with SLM technology. “To reduce our spares requirement, we standardised on one rating of servo drive and motor,” explained Stuart Baker.

The result? At a time when the plant has increased from 12 hours to 20 hours a day operation, just 13 people are needed on this line, allowing the remaining 14 to be redeployed elsewhere in the plant. This has given a saving of some £180,000 a year and an increase in line capacity.

“This area was previously a bottleneck, with a maximum throughput of 1.2 tonnes per hour” says Stuart Baker. “Now, with half the people, we are working towards a target of 1.7 tonnes an hour on all products!.”

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.

“To simplify the mechanical design of the machine, we have used three of the six axes paired (two servomotors on each shaft),” says Stuart Baker.

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 highspeed multi-axis control (1 ms 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.

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.

 “SLM was a key factor in our choice of the Control Techniques system,” says Stuart Baker, “and we have found it greatly simplified not only the build and installation, but also, with its extensive diagnostics, has reduced maintenance time too. We went on a two-day training course and that was all we needed, although we do get excellent support from the Telford Drive Centre and they were particularly helpful during the development phase. The system really is easy to use – we can even adjust gains whilst the machine is operating – we’re all very impressed.”