Tabasco® brand products have been made by McIlhenny Company on Avery Island, LA, since 1868. The company is extremely quality-minded about everything from aging its product for up to three years to making sure every label is correct, straight and in the right position on the bottle. The McIlhenny Company has embarked on an effort to perform 100% inspection of the three labels on each bottle to ensure that the right labels were correctly positioned on every bottle. The biggest challenge in performing machine vision inspection is that the bottles can be oriented in any direction as they come down the line.
The inspection challenge
Each bottle of Tabasco Sauce has a diamond label on the front, a rectangular label on its back, a wrap on its top neck, a cap, and a fitment underneath the cap to control flow out of the bottle. The company makes products with hundreds of different labels for Tabasco Sauce lovers around the world. McIlhenny Company has four different bottling lines that are used for bottles ranging in size from 2- to 12-ounces. The lines operate at around 300 bottles per minute.
“We use hundreds of different labels and it’s critical to ensure that the correct label is affixed to every bottle,” says Tom Grimsley, Jr., Bottling Manager, McIlhenny Company. “For example, if we produce an order intended for Germany with Austrian labels we will not only have an unhappy customer but also considerable expenses to remake and reship the product. We also want to be sure that every label is straight and in the correct position.”
“In the past we used infrared light and photoeyes to inspect labels,” Grimsley says. “The previous method was capable of determining whether the label was in the correct position but could not determine if the label itself was correct. We decided that we needed to find something better.
About two years ago, Grimsley and Tabasco’s purchasing manager, night shift manager and maintenance manager went to a packaging tradeshow to look at the latest vision inspection systems for bottling lines. The team selected Acquire Automation (www.acquire-automation.com) to come up with the solution for 360-degree inspection. Their product uses Cognex (www.cognex.com) OmniView to produce a complete image of the circumference of each bottle.
“Their system offers an operator friendly human/machine interface and can easily be programmed for new labels and bottle sizes. We also liked the fact that their system measures 30 inches by 30 inches so it easily fits within the footprint vacated by our previous inspection system,” continues Grimsley.
Move to 360-degree inspection
Complete 360-degree inspection of unoriented bottles, tubes and cylindrical containers has traditionally required line scan vision technology combined with complex mechanical handling devices for image acquisition. Acquire Automation’s approach enables less intrusive integration options and higher throughput rates. The system also allows for label inspection on the container, assuring a higher degree of label integrity compared to label web inspection prior to application. The inspection station can read barcodes, verify text, inspect graphics and measure features at production line speeds of up to 1,200 parts per minute.
Units can be in any orientation as they pass through the vision inspection system. The Acquire Automation system selected by McIlhenny Company uses four cameras to obtain a 360-degree view of all features of the bottles. Cognex OmniView vision software technology uses images from multiple area-scan cameras positioned around the cylindrical object to instantly generate a virtual 3D surface model. It then creates a seamless, undistorted, unwrapped image of the complete surface to which optical character recognition, barcode reading, and other machine vision software tools can be applied.
Vision tools verify label is correct
Acquire Automation uses Cognex VisionPro vision tools to configure the label inspection routine. After a color image of the circumference of the bottle has been acquired and stitched together, a combination of pattern recognition and color matching tools are used to identify the label and to confirm it matches the current production run. Programmers set tolerance limits so incorrect labels cannot pass inspection.
After the label has been identified, a series of line tools are used to determine the vertical position of each label in relation to the ends of the bottle and the angle of the label in relation to the axis of the bottle. The position and angle of the label are matched against allowable limits. Additional inspection tools are utilized to check for bottle fill level, ink-jet code print presence, skewed caps, and damaged labels. New labels can be added to the system simply by running some through the system and setting a few unique search regions in the teach mode. Acquire Automation engineers also use remote access to perform troubleshooting without having to travel to the customer site.
Painless implementation process
Acquire Automation configured the system in their own facility prior to shipment to McIlhenny Company. The company’s engineers calibrated the cameras and used Cognex VisionPro tools to train the system to identify each of McIlhenny Company’s labels. “The installation and implementation of the system were painless,” Grimsley says. “It’s a very user friendly system and has been well-accepted by the operators. The vision system communicates with our programmable logic control to reject nonconforming products and to shut down the line if consecutive nonconforming products are identified.”
Grimsley says the inspection system has already paid for itself, primarily by ensuring that only conforming products are shipped to customers. He also says that the overall quality of the product has been improved. “If something goes wrong with the equipment that is causing skewed labels, we can identify the problem on the very first label,” Grimsley says. “Overall, we are more comfortable with our quality and feel confident that every product we ship conforms to our standards.”