New Preform Inspection System by INTRAVIS: PreWatcher® III

Six high-resolution cameras for side-inspection

The new INTRAVIS PreWatcher® III is the latest release in their line of high-speed preform inspection systems. With its innovative space saving design this system can seamlessly integrate into the production line to perform a comprehensive inspection of each preform for defects. The new PreWatcher® III effortlessly meets the increasing demands of injection molders.

Unlike its predecessor, the PreWatcher® III is self-contained with a high-tech centrifugal feeding unit already included in the inspection system. By combining both the feeding unit and the inspection system, INTRAVIS is able to fit the system into 8m² of floor space with a maximum height of only 2.5m! Small and fast, the new PreWatcher® III can inspect preforms at fast speeds of up to 72,000 per hour, providing an inline 100% inspection system for even the most demanding production environments.

INTRAVIS has forged new paths in the state-of-the-art handling system for the preforms. To ensure optimal preform presentation to the cameras, the preforms are separated by the VT wheel then picked up by individually rotating vacuum plates. By rotating each individual preform, all of the 8 cameras are ensured a perfect field of view for the inspection. The newly developed top sealing surface inspection with color camera and bicolor multi-angle lighting detects scratches and notches in the mouth area without being distracted by possible parting lines. While the proven technology of the predecessor was adapted for the inspection of the injection gate point, the PreWatcher® III performs side wall and thread inspection with a total of 6 high-resolution cameras. True to the INTRAVIS motto “A higher amount of data leads to more powerful decisions”, these cameras take various precise images while the preform is rotating, thus creating a roll out image of the preform surface for the image processing system. The patented background suppression method suppresses the image from the rear side of the preform on translucent preforms, enabling the system to see and evaluate contamination, streaks, scratches, unmelts, oil splashes etc. At the same time the geometric characteristics, as well as the wall thickness, of the preform are being measured. Virtually all thread dimensions are measured by the cameras particularly aligned to the thread area. Simultaneously, the cavity numbers are being read, allowing for sorting of preforms by mold cavity numbers or creating cavity-related statistics. This works also for opaque preforms. To complete the inspection, detection of color deviation in the l*a*b* color space as well as the transmission in the UV and IR wavelengths is accomplished using a spectrometer. All references are taught through a training program. Tolerances for all measured values may be defined via the touch screen of the completely updated and cutting-edge user interface. Preforms that don’t meet these requirements are removed from the production process and the remaining good preforms are counted.

The PreWatcher® III cannot only be integrated behind an injection molding machine but can also be used offline for batch inspection of large preform batches. INTRAVIS offers the necessary downstream equipment such as octabin or gaylord tipper, bunker and diverter for the packaging of the inspected good preforms. These components are optimally suited for the system and are controlled by the PreWatcher® III interface.

PreWatcher III at INTRAVIS-Booth: 11A58