German filling and packaging specialist KHS GmbH has developed a multi-stage inspection program which tests PET preforms.
Called the Innocheck PPI, the system can recognise faulty preforms by finding foreign objects and detecting even the smallest amount of damage.
It helps ensure an efficient stretch blow-moulding process with a detection rate of almost 100 per cent.
KHS estimates that close to 40 per cent of all stretch blow moulders are now fitted with an inspection system, and the supplier is now integrating its own Innocheck PPI preform inspection unit, developed in-house, into its plant engineering.
This supplements its Innocheck portfolio, which also includes the Innocheck PCI PET container inspector.
Typical faults detected by a preform inspector can be foreign objects in the preform, or the slightest damage to the preform's sealing surface which could cause leaks and products to spoil at a later date.
If the preform which enters the stretch blow moulder is faulty, this can be clearly detected.
The Innocheck PPI preform inspector is directly integrated into the stretch blow moulder's preform separator, where it first assesses the quality of the sealing surface.
A second end cap imaging camera then detects any distortion or contamination of transparent and practically opaque PET preforms.
The smallest deviations in colour are also ascertained, and the preform length determined with an accuracy of ±1 mm.
Image processing software evaluates any possible errors in real time, enabling up to 81,000 preforms to be inspected every hour.
Faulty preforms are reliably rejected prior to stretch blow moulding, saving on compressed air and increasing line availability and consumer safety. As a result, the number of rejected blown bottles is reduced.
