Overview:

The Blister Packaging Cell is an automated system to package electronic toothbrushes for point of sale display. The blister packaging cell is an example of a machine tending work cell.

Process Description:

Product is delivered to the system on matrix trays.  Four versions of the product, distinguished by different colors, may be packaged at any given time. A SCARA robot uses fixed machine vision sensors to locate individual brush heads in each tray, load one or two brush heads into a pallet.  The number of brush heads is determined by the packaging configuration.

The pre-arranged brush heads are carried to the loading station, where they are grabbed simultaneously by another SCARA robot, and placed into the plastic blisters. As the brush heads are inserted into the blisters, a cardboard liner is held above the blister.  The insertion of the brush heads forces the cardboard liner into place in the blister, wrapping around the brush heads.  The line provides product information and hides the lower portion of each brush head from view.

The loaded blister packs are then heat sealed with a back-card, and loaded onto a conveyor belt, which takes the finished packs to operators for manual loading into corrugate containers and POS displays.

Technical Challenge:

Placement of the cardboard liner proved to be a very difficult challenge.  Initial concepts for the system had the liner installed separately from the brush heads.  However, tests showed that the liner did not remain seated in the blister with any great reliability. Though seemingly risky, it was determined through testing that holding the liner over the blister, and dropping the brush heads in place, was the only reliable method for placing the liner. Once this determination was made, it was also challenging to build a custom feeder for the two liner styles, and then create a gripping system that could pull the liners from the bottom of a large gravity-fed stack, but release the liners as the brush heads were pushed through. The final solution involved the use of a "helping hand" concept, where the liners were pulled from the stack with one gripper, fitted with strong rubberized vacuum cups, and then transferred to another gripper with a slippery vacuum system, comprised of holes in an aluminum plate.