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Send to KindleGerman firm uses machine vision for toothpaste tube inspection
The conveyor system moves the tubes clockwise toward the cleaning and filling station. Before they reach that station, a scanner checks that the tubes are aligned correctly so that the printing is in the correct position when the base is sealed later. Two successive inspection stations check that the tubes are round in shape and clean before they go through cleaning and filling stage.
Two In-Sight 5100 cameras installed above the conveyor and the work areas evaluate the tube ground coat, the shoulders of the tube, and the inside of the tube cap during the particle check. The cameras detect foreign bodies based on the contrast to their surroundings. A red, ring-shaped LED light illuminates the inside of the tube from above. Any undesired particles cast a shadow that’s detected by the Cognex cameras, making it possible to detect objects that are the same color as the tube itself.
During the subsequent tube roundness check, two In-Sight 5100s check whether the tubes are of the required shape. If the tubes do not have the specified roundness, the nozzles stay at the edge during the cleaning and filling process and ram the packages into the tube holders. The technology ensures that the nozzles enter the tubes accurately to within a tolerance of three millimeters (0.12 in.). The checking procedure takes place without the need for an additional operation step during the process. The individual cameras receive a trigger for every tube and record pictures of the packages as they move past. If a tube is out-of-round or outside of the tolerance range, it is identified as faulty and is not filled. Further on in the process, the TFS 80-6 seals the tube and ejects it from the production line.
Seal verification
After cleaning and filling, the laminated plastic tubes are sealed with hot air. The ends of the tube are heated by hot air at a temperature of 380° to 450°C (716 to 842°F) and are then pressed together by cooled stamping jaws. The seal is either stamped smooth or in a corrugated pattern and may feature a serial number or code. Defects can occur at this stage of the packaging process. For example, if a knife becomes blunt and can no longer cut off the ends of the tubes correctly, the seal will be left with rough edges. In the trimming station, two In-Sight 5400 cameras ensure that all faulty packages are detected without fail. The cameras also check the seal itself. If the seal is not complete, or if the printing is not properly aligned with the specified parameters, the faulty tube is ejected from the process.
Saving time and reducing overall costs
The In-Sight vision systems are networked to a central panel PC that records all of the images of faulty pieces. This makes it possible to detect faults quickly without having to recheck the actual item of packaging that has already been ejected from the process. The packaging process of IWK is reliable in terms of the quality standards achieved.
Article supplied by Cognex
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