It was only with the advent of robot technology that the concept of grouping chains for the optional grouping of individual products became a feasible possibility. The functional principle is a simple one. Products run into pockets (tools) which are mounted on two chain lines. Once the required number of products for a group has been collected in one of the lines, it moves to pick-up positon. One of the tasks of the control system is to monitor the product spacing and to separate out products where necessary - quite a challenging task at high infeed rates. The grouping chain is offered in a horizontal and a vertical operating version. The trend towards transposing mechanical functions into software applications has now also taken off in the packaging machine sector. Taking this a stage further, grouping chains themselves are likely to give way to vision systems in the foreseeable future .