Most bottling plants handling PET containers blow-mold the bottles themselves from outsourced preforms. For the quality of the blowmolded bottles the quality of the preforms is inevitably crucial. Krones has accordingly developed an inspection unit which checks the PET performs either after the unscrambler or on the infeed wheel of the Contiform stretch blow-molding machine. At speeds of up to 72 preforms an hour the perform inspector monitors compliance with ovality inner diameter and quality of the sealing surface.
The IRIS technology used here photographs the raw preforms with a high resolution of 0.05 mm/ pixel using special light sources and a camera installed above the passing preforms. The camera itself detects even the tiniest of preform defects with 640 x 480 pixels and 12-bit halftone resolution.
