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Cognex Corporation designs, develops, manufactures, and markets a range of products that incorporate sophisticated machine vision technology that gives them the ability to “see.” Cognex products include barcode readers, machine vision sensors, and machine vision systems that are used in factories, warehouses, and distribution centers around the world to guide, gauge, inspect, identify, and assure the quality of items during the manufacturing and distribution process. Cognex is the world’s leader in the machine vision industry, having shipped more than 1 million vision-based products, representing over $4 billion in cumulative revenue, since the company’s founding in 1981. Headquartered in Natick, Massachusetts, USA, Cognex has regional offices and distributors located throughout the Americas, Europe, and Asia.

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Industry:
Food & Beverage Food & Beverage

Application:
Visual Inspection & Testing Visual Inspection & Testing

360-Degree Inspection of Unoriented Bottles Helps Ensure Highest Possible Levels of Quality for Tabasco® Brand Pepper Sauce

POSTED 05/28/2014

Tabasco® brand products have been made by McIlhenny Company on Avery Island, Louisiana, 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. A few years ago McIlhenny Company 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.

History

Edmund McIlhenny, a food lover and avid gardener, was given seeds of Capsicum frutescens peppers that had come from Mexico or Central America in the 1860s. He grew the seeds on Avery Island, mixed the peppers with salt and aged this mash for 30 days in crockery jars and barrels. He then blended the mash with vinegar and aged it for another 30 days. The sauce proved so popular with family and friends that McIlhenny decided to begin making it commercially. Over 140 years later, Tabasco Sauce is made much the same way except that now the aging process for the mash is longer and the vinegar is high-quality distilled vinegar. Labeled in 22 languages and dialects, Tabasco Sauce is sold in over 160 countries and territories around the world.

Difficult 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 ounces 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,” said 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. Since we produce a premium 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 said. “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 are very quality-minded so we decided that we needed to find something better. About two years ago I went to a packaging trade show with our purchasing manager, night shift manager and maintenance manager to look at the latest vision inspection systems for bottling lines. We concluded that Acquire Automation had the best performing solution for 360-degree inspection. Their product uses Cognex OmniView to produce a complete image of the circumference of the 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.”

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 (OCR), barcode reading, and other machine vision software tools can be applied. Acquire Automation’s vision system uses Basler Gigabit Ethernet cameras to acquire the image. Human machine interface (HMI) software is used to log in and train new products on the system. The HMI runs on a computer with 8 to 12 CPU cores and a dedicated Ethernet network interface card for each camera. “This inspection system provides confidence in the quality and conformance of every product we ship,” said Grimsley.

Vision tools verify label is correct

Acquire Automation used 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, raised/skewed caps, and flagging/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 said. “The entire process was very seamless and integration was very simple. 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 said the inspection system has already paid for itself, primarily by ensuring that only conforming products are shipped to customers. He also said 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 said. “Overall, we are more comfortable with our quality and feel confident that every product we ship conforms to our standards. I want to mention that one of the nice things about working with Acquire Automation is that they make you feel like you are their only customer. We have only had a couple of problems with the vision system but in each case they have responded very quickly and effectively to provide effective resolution.”