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This is another example of the "conveyor as production process", as opposed to a conveyor that just moves things from A to B.
Our customer has long strips of foam, which are passed into a cutting machine that cuts them into lots of little pads the size of a kitchen scouring pad. One day, they thought "hey.. if we can stack three strips on top of one another, the cutting machine can cut three times as many pads on each pass".
.. and that's when our phone rang !
One key parameter of the job was that this must be a continous process. The input feed cannot be "paused" while the stacking is accomplished. But of course not.. that would make it too easy !
Our solution was a "nodding donkey" quad-stacked conveyor system. There are four conveyors, vertically stacked. They are fixed at the output end, but can move up and down at the input stage, courtesy of an indexing crank mechanism. This allows a different conveyor to be presented to the input feed conveyor each cycle.
So a strip will trundle down the input feed conveyor, and be transferred onto conveyor #1. The quad unit then indexes, so that the NEXT strip on the feed conveyor is presented to conveyor #2, and the next to conveyor #3.
The system in this picture is in our factory, prior to calibration, which is why the three sheets are NOT quite aligned on top of one another correctly.
We've got a short snippet of video to illustrate this.----------------------
The key to success of this system are the sensors on the quad conveyors, and a rather complex control panel. Bear in mind that the belt emerging from conveyor #1 will have further to travel than the one on conveyor #3, so the system must continously adapt the drive motors of the four conveyors to compensate for this, otherwise the belts won't be perfectly stacked vertically, and this would result in wastage as - when cut - the first group of 'scouring pads' will be shorter or longer than the others.
This required a somewhat complicated control panel, with a PLC monitoring the sensors and adjusting the drive inverters, in addition to sending the appropriate indexing signals to the crank mechanism.
The final installed system featured safety cages with electrical interlocks: if any of the cage doors are opened, power is immediately cut off to the system
It took a lot of careful adjustment and calibration once on-site, but the end result was very succesful, maintaining continuity of production with virtually zero waste. The customer was delighted, and is currently negotiating with us for another similar machine !