Flexible production with faster neck changes on the stretch blow molder

Thought through to the end

In order to considerably speed up the conversion process as a whole, KHS has not just simplified the individual work steps involved but also the concept governing the entire procedure. “We started out by analyzing how the operators work,” says Arne Andersen, stretch blow molding product manager. “On this basis we then considered how all tasks could be made easier and organized as perfectly as possible - paying particular attention to the ergonomics. Magazines were thus installed that stop the operator having to repeatedly abandon the machine to fetch and carry change parts, for example. We also replaced the grippers to reduce the number of screws that need to be loosened. At the same time, newly developed mandrel heads are now used that can be simply removed by pressing a release spring. This process used to be much more complex.”
Step 1 shield changeover (source: Jörg Schwalfenberg)
When converting the stretch blow molder to a different neck, the shields are first exchanged.

In this case, KHS consciously went for an approach that thought all of the specific processes through to the end based on actual customer requirements, Andersen emphas. “We aimed to achieve the best possible improvement within the shortest possible time.” KHS managed both: thanks to the simple neck change, the time needed for two operators to convert the KHS InnoPET Blomax16 stretch blow molder, for instance, has now been cut by a good two thirds to approximately just 86 minutes - including the preform infeed. As the PET bottles in a block like the KHS InnoPET BloFill are held and conveyed by their necks throughout the entire machine, not only the stretch blow molder but also the filler has been developed further in order to shorten conversion times. The capper was one particular area of focus, where the cone responsible for lifting and closing the bottles needs to be replaced manually. No conversion is required regarding the screw cap, however, as there are two cap feeds - one for each neck diameter in the respective format.

Step 2 mandrel head changeover (source: Jörg Schwalfenberg)
The mandrel head is released by simply pressing on a spring, enabling it to be changed over quickly and easily.

Greater flexibility, less storage space

Andersen is convinced that the new neck change option will give beverage producers much greater flexibility, as they can now also run much shorter production cycles for bottles with different necks and therefore reduce their warehousing effort accordingly. “Some of our customers produce just in time; this means that the finished containers are loaded straight onto the truck without any interim storage. The drastically reduced conversion time will now enable filling operations like these to change necks more frequently; they thus profit from totally new options in their production planning.” The same goes for converters who can now produce the generally smaller batches for their customers - often in very different bottles - on a single line much more efficiently. The first customers in Asia who are already using the quick neck change developed by KHS are extremely pleased with the amount of time and effort they save. This retrofittable option has thus earned plenty of praise from KHS’ clients in this region.