What is an accumulator?

In many cases, an accumulator is simply a series of rollers used in the same function as a dancer roller, but with the ability to accumulate and dispense much longer lengths of web.

Accumulators are most commonly used with unwinders or winders to allow a zero-speed splice, without interrupting the speed of other processes on the web line, such as coating or drying.

What is the sequence using an accumulator for zero-speed splicing?

  1. The main process continuously runs at constant speed.
  2. The winder or unwinder decelerates to zero speed.
  3. The accumulator’s festoon moves, accumulating (ahead of winders) or dispensing (downstream of unwinders) the amount of web equal to the speed differential x time.
  4. The manual or automatic splice is made at the winder or unwinder.
  5. The winder or unwinder is accelerated to 50-100 percent over the main line speed to either refill the unwinder accumulator or dispense the web in a winder’s accumulator.
  6. As the accumulator returns to its starting position (fully dispensed for winder or fully accumulated for unwinders), the winder or unwinder ramps down to equal the main line speed.
  7. The accumulator is ready for the next splice.

Most accumulators are force loaded and float to a position determined by the input and output speed differential. Some accumulators are speed controlled, driving the web to a calculated position, again based on the input and output speed differential and usually coupled with a standard dancer roller to make up for small speed variations.