PET lines today are very rarely configured exclusively from individual machines. Instead, beverage producers want a turnkey system with a small footprint, shorter conveying segments and a reduced maintenance effort and – first and foremost – short changeover times. As part of the holistic, automated line changeovers on its PET lines the InnoPET stretch blow molder, labeler and filler TriBlock satisfies these high demands. Thanks to the new KHS InnoPET iflex automation concept beverage bottlers can now save up to 70% of the time needed for manual changeovers. To this end, various functions were developed for the different segments on the InnoPET TriBlock that considerably increase the level of automation and make manual intervention largely superfluous with a few clicks on the HMI.
Format changeovers by robot
PET bottles are produced in the stretch blow molding module. When formats are scheduled for a changeover, the iflex first triggers the automatic loading of recipes for the heating profile, blow pressure, preform conveying and inspection technology.
The most important new feature on this machine is the mold changeover when the new batch requires a different bottle size or shape. Here, the switch is made with the help of a robot that changes the two side mold shells and base mold fully automatically and very quickly during ongoing production. It removes the previous molds from the stations, places them in the mold set magazine, takes out the new molds and slots them back into the stations without any need for action from the operator. The robot needs just 41 seconds per station for this short, fully reproducible procedure. The time for manual intervention is thus reduced from a previous 95 to just eight minutes. This is further facilitated by automatic bottle base detection adjustment at the blow wheel transfer star with the help of several sensors. All the operator has to do by hand is to start the format changeover and later start the new production run.
Less manual intervention
The time and effort needed for manual work by the operator is also reduced in the labeling module. This is chiefly thanks to automatic adaptation of the label gluing height and bottle diameter. The operator still carries out the toolless changeover of the vacuum drum, brushes and bottle guide parts, however. Nevertheless, two labeling stations can now be converted within 20 minutes.
At the press of a button
In the filler module conversion is fully automatic. Firstly, this avoids handling errors by the operator, and secondly, it prevents the risk of bacterial or microbiological contamination by people entering the hygiene area that would then need foam cleaning. This would delay the changeover by around 30 minutes.
The key components relevant to automatic changeovers are the guides from the filler infeed to the capper discharge that need to be set to the bottle diameter and height. Conical base guides or bottle pockets are used here, for example, where the containers are fixed by simple height adjustment as in a funnel. The discharge conveyor is vertically adjusted by a servomotor instead of being manually cranked; the same goes for the horizontal adjustment of the railings. What’s more, the bottle caps are also changed over automatically, such as when a new beverage features a different cap color from the previous one.