Can line control in Seville

Controlling Partners Canmaking in Europe has recently had an enormous boost by the opening of the first new canmaking plant in ten years.

Crown Cork and Seal, one of the world's leading packaging manufacturers, is now successfully producing cans from this new plant in Seville, Spain.

During the initial planning stage it was decided by Crown Cork and Seal to continue to use Allen Bradley systems for line controls and Sencon sensors as part of the control package of the conveying system as these were seen to be the best for ease of understanding and reliability.

Systems integration specialists, S J Systems (Oxford), were chosen to assist with the base engineering and on site commissioning of the line control conveying system, as well as the final stage training of the on-site workforce.

Crown Cork and Seal and S J Systems (Oxford) worked closely together to produce the control philosophy.

From this agreed philosophy S J Systems engineered and wrote the line control software for the complete control of the conveyors and ensured full integration with the relevant machines over an ethernet network.

As a part of this control philosophy, over 300 Sencon sensors were fitted on the new can making line in Seville.

This is a testament to the trust placed in Sencon sensors as a result of long term customer experience.

The key to building this trust is the fact that the sensors had been designed and proved specifically for the can-making environment, with a broad range suitable for any of the line control problems which might arise.

One key example is the use of the Area Mass Sensors (AMS) on the cupper mass conveyor, which carries cups to the infeed of the bodymakers.

The line control must ensure that there is a sufficient volume on the mass belt to feed all the running bodymakers, and to avoid the stop/start running which is so detrimental to their efficiency.

By mounting a Sencon analogue AMS sensor onto the cup mass belt, a number of control functions are possible.

The bodymakers will not start until the can density on the mass belt is above 30%, and they will stop if the density falls below 5%.

Cups which pass all the bodymaker infeeds are recycled to the beginning of the belt by a recycling conveyor.

The speed of this conveyor is also modulated by the AMS to create a constant flow of cups to the bodymakers.

The single AMS sensor provides all the data necessary for the effective day-to-day control of the mass belt infeed to the bodymakers at Seville.

Another solution was found for the intermittent stop-starting of the low level inspection mass belts.

Standard proximity sensors are unable to distinguish between stationary or moving cans, once the cans are in-front of the sensor.

Sencon's innovative "motion sensor" detects the movement of cans only and so creates a more meaningful signal to the control system eliminating unnecessary stops.

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