The Gluing Process in Tray Formers
The carton then moves forward to the gluing station. Depending on the application, the gluing technology and placement are different. 4 and 6-point glued trays are usually glued by applying the adhesive from overhead pots to diagonally folded back flaps. For example, chip scoops can be glued with top mounted glue guns. Hamburger clamshell boxes, on the contrary, use bottom mounted guns. CE1000 tray formers can also work with rotary stencils.
The adhesive can be hot-melt or cold vinyl. If the package will have to withstand heat, it is advisable to utilize cold glue. Heiber + Schröder tray formers come with cold glue systems but have been configured with additional hot-melt equipment as well, by many of our clients.
Heiber + Schröder CE1000 tray formers have a standard cold-glue rotary stencil system which consists of 6 individually movable gluing discs with four normal and two double-width glue pots and bottles. The bottle is placed to maintain a constant glue level automatically. The glue quantity is metered by a small easy to handle thump wheel.
To build chip scoops, H+S tray formers use top mounted glue guns, moving in a lateral direction symmetrically on an oscillating shaft to create the right conical glue pattern. Each lane has two nozzles, and up to four lanes can operate simultaneously.
For hamburger clamshell boxes, the glue guns are mounted below, in a configuration of 4 nozzles per lane.
To prevent improper glue application, if one or more blanks fail to arrive, H+S tray formers automatically stop.
It is very important to ensure that the carton blanks do not skew and that the glue is applied exactly where intended. Glue splashes or squeeze-outs may prevent the package from opening properly in the filling line.
The Forming Tower
After glue application, the carton moves to the forming tower through top and bottom belts. The tray former's conveyors position it in front of the pusher (also called mandrel or plunger), which exerts pressure on the carton against a matching cavity, making it fold along the creases with the help of metal or plastic fingers and plows. The glued flaps fall in position and are pressed for adherence.
Here, the bending force must be very precise. Heiber + Schröder tray formers utilize servo motors to a move the pusher, which is readily programmed for various tray styles and formats. The forming tools (pusher and cavity) are specific to each tray style. However, they can be modified within the machine's size range, to produce different folding carton formats.
The glued and folded cartons move along the tray former's delivery section accumulating in a shingle pattern. Each lane is individually counted and separated into corresponding batches. They are later removed for delivery to the client.
The entire gluing and forming station is movable, on wheels, providing free access. This makes adjustment tasks easier and reduces changeover times.
Tray Former Productivity Enhancements
An additional flex-tower, allows the operator to carry out most of the setup for the next job off-line, without stopping the current batch. When the carton style changes, he/she removes the flex-tower and plugs in the new one. A single off-line unit can be shared across several H+S tray formers