As machine vision technology becomes increasingly reliable and cost-effective, manufacturers are finding it easy to integrate into their packaging lines. Due to the rapid development of machine vision and inspection systems, more tools are becoming available for quality control in the packaging processes of many manufacturers. One fast-moving consumer goods brand, Alltrista, produces two-piece cans in India. The company uses Omron's F160 camera image sensor to inspect each can as it comes off the line, allowing damaged cans to be rejected before they reach their final packaging location. The company initially installed eight imaging systems and has now increased that to eighteen. Some of the earlier imaging systems required more powerful air conditioning units to cool the electronic components. These air conditioning units frequently malfunctioned and were very expensive to maintain, and these systems had already reduced cycle times, becoming a major obstacle to increasing productivity. The Omron F160 , however, offers many advantages in compact packaging. It allows two systems to be installed in the space where previously only one system could be installed, saving space and completely eliminating the need for an air conditioning unit. This is because the complexity of the system is simplified and the cost is reduced through good design. The F160 system can capture an image of the lid and send it to a PLC for comparison to prevent defects in the lid. This PLC is pre-programmed by Alltrista engineers and quality control personnel. After the PLC determines the good/damaged state of the lid, the result is stored and tracked until the lid reaches the discard state. At the discard state, a signal from the PLC activates the discarding mechanism, which removes the damaged lid from the conveyor belt. The F160's menu is very simple and easy to use; it even offers networking and data collection capabilities, which lays a very good foundation for the full integration of packaging systems. Barcode Camera The latest development in machine vision technology is seen in lens conversion; one eyewear manufacturer has been able to make lenses darken when exposed to sunlight. Pinellas Park, FL, has begun operating a new machine vision system that ensures accurate marking on lens cardboard boxes. Older machine vision systems wouldn't allow companies to automate entire production lines, but the Cognex Insight 4001 high-resolution image sensor can read two-dimensional codes that indicate the end-of-line status of box-labeling machines. "We've transferred a two-dimensional etched model onto our lenses," says Chris Rauscher, project manager at Transitions Optical. "It's something like a barcode, square-shaped with no vertical lines, made up of a series of small dots. The advantage is that you get a lot of numbers, which can form a very small mark, called a data model. Other digital imaging systems sometimes confuse the numbers. This new coding helps us ensure the lenses are in the right cardboard box, and it also contains more information we've discussed earlier." The information included in this small code includes which eye the lens is designed for, magnification intensity, and color. The Cognex sensor, with a resolution of 1024x768, is mounted in a closed chamber. This level of resolution is crucial because it allows the company to obtain an image of the entire lens, rather than just a portion, for identification; the system operates at 20 lenses per minute. A conveyor belt carries each lens into a closed sensor chamber. Cognex sensors use software written by Rauscher to locate a two-dimensional code suspended at the top of the sensor cabinet using a pattern-finding tool. A 12-digit string is obtained from the code and sent to a PLC provided by Rockwell, which can compile the code and send the information via a network to the printing and labeling machines. The lenses exit the sensor cabinet and are moved into the carton forming machine. The cartons are then transported through the labeling machine, where they are identified by appropriate pressure-sensitive labels from the printing and application labeling machines. The primary reason for this work is to automate other parts of the production process. This new two-dimensional coding allows for the establishment of relevant information links between other machines in the process, making full automation of other parts of the packaging line possible. Printing Press Inspection System Not only packaging manufacturers, but also semi-finished product processors are finding machine vision useful. Farnell Packaging Ltd. is one such example. This Canadian manufacturer of deformable packaging and pressure-sensitive labels recently installed AVT's Printvision/Pro automated inspection system and Automated Barcode Authentication (ABCV) module to maximize the productivity of its new Windmoeller & Hoelscher Novoflex® (superscript) driveless flexo printing press. AVT's automated registration pre-adjustment and control system has also been installed on the new 52” eight-color printing press. The addition of the inspection system is expected to enable the company to reduce costs, improve competitiveness, and solidify its current business. "When we decided to introduce the Cadillac printing press, which we considered to have the latest servo technology, we also wanted to have a corresponding quality control system to ensure compatibility during operation." “Dan Christianson, Vice President of Operations at Farnell Packaging, said. AVT’s Printvision/Pro system can identify defects by taking a master digital image of the printed image before the job begins. During operation, if the sensor detects a difference between the master image and the image being printed, the sensor should alert the operator, allowing the operator to see the error displayed on the Printvision control monitor. The system can be used on various types of materials, including paper, foil, and translucent or opaque films. It can detect color differences, splattering, misreading, fogging, streaks, printing errors, and spots. For Farnell, the vision system detects subtle problems on the polyethylene film, which, while visible to the naked eye, have the advantage of indicating trends that can deteriorate or lead to waste over time—a warning that the naked eye may not be able to provide.” This proprietary machine vision technology automatically identifies and authenticates all barcodes printed on products, ensuring product quality and verifying all barcode parameters. Unlike laser scanners, ABCV cannot scan every barcode and display the results on a screen. Operators can see relevant information on the screen and identify and resolve problems. The barcode verification system captures a video image of each barcode and uses AVT software to analyze the image and derive a "grade." If the determined grade is lower than an acceptable pre-programmed value, the display will suddenly jump to the operator's data window. "I know AVT's inspection system is helping us improve our productivity," said Don Farnell, the company's chairman and founder. "With these new printers, we have increased our ability to see all the details and detect any defects, and the detailed process records we print for our customers are very important." " Quality Control " A Canadian aluminum bottle cap manufacturer also uses a pair of SmartImage Legend 540 image sensors to inspect its products. Installed last year, these sensors are capable of inspecting the printed lettering on the top and sides of the aluminum bottle caps. They use one camera to observe the top of the cap and another to observe the sides, with system integrators assisting in the installation of the DVT system. At the top, they position the markings and confirm they are not off-center, and at the side, they confirm the printed lettering is present. If the markings are off-center by more than 1.5mm, the cap is ejected into a waste cap bin via an air jet device at a speed of 250 caps/min, with production time completely unaffected by images of damaged caps. Thanks to this new machine vision system, Capalux hears far fewer complaints and returns from customers, achieving significantly higher quality and efficiency than manual inspection. After printing on the caps, they enter the DVT inspection position. Before being counted and boxed, the good caps need to be moved to another production location.