Three sets of eyes
X-ray, metal detection and vision technologies keep the quality in your packaging systems.
By Judy Rice, Contributing Editor | 02/24/2005
Super Store dairy plants produce plain, pre-stirred and fruit-on-the-bottom yogurt varieties. Notes Hopper, “The X-ray system has no problem with fruit or yogurt densities. We only have to set up for size changes. Our product sizes are programmed into the system. So it is as simple as selecting the size on the operator screen and adjusting one guide rail to product width, and we’re ready to run.”
Hopper says the speed of our production lines, ranging between 180 to 280 cups per minute, is no problem for the system. “We can even run the cups touching side-by-side and still only reject the cup that is suspect,” he continues. “This is unlike our metal detector, which needed spacing between the cups. This has helped significantly lower our error count of good product that gets wrongly rejected.” He also notes no major conveyor modifications were required, and the set-up and control screens are operator-friendly.Vision systems in focus
On today's high-speed production lines, it’s increasingly challenging to check the integrity and critical features of packages, such as proper marking and logo placement. Increasing production line speeds and frequent changeovers further increase the difficulty of ensuring the proper filling, capping, sealing, labeling, and packaging of products.
Machine vision systems provide the watchful eye to assist with quality assurance. According to Cognex Inc. (www.cognex.com
), Natick, Mass., vision systems can perform such checks as:
- Label presence and skew
- Cap presence and position
- Package integrity
- Print presence verification
- Print quality inspection
- Date and lot code verification
- Safety seal presence
- Fill level detection
- 1D and 2D code reading
- Insert presence verification
- Package color and shape sorting
- Bottle counting
Private label frozen pizza maker Frozen Specialties Inc., Archbold, Ohio, uses a Cognex system to detect unboxed pizzas, pizzas damaged during wrapping and open carton flaps. The pies are inspected twice at 175 pizzas per minute.
Alltrista Consumer Products Co., Muncie, Ind., which manufactures two-piece canning closures, uses F160 vision systems from Omron Electronics LLC to achieve real-time lid defect detection. Alltrista captures an image of each lid. That image is sent to a PLC for comparison against programmed defect limits. After the PLC determines if the lid is good or bad, that status result is stored and tracked until it reaches a rejection station, where a PLC signal activates a mechanism to remove the bad lids. The F160 system inspects lids being transported from the curing oven to the final packaging area at the rate of 160 lids/minute.
), Schaumburg, Ill., also has several other vision sensor systems to accommodate on-line applications for a broad range of packaging types. The F500 vision sensor has a 1 million pixel digital camera to deliver high-precision image sensing. The system captures up to 200 images in compact flash, easily transmitted in batches to permanent storage. The system features two separate image processors: one for judgment and one for communication.
|Antibody-based inks spell food safety
Toxin Guard, a patented package printing technology developed by Toxin Alert Corp. (www.toxinalert.com), Jackson, Miss., provides consumers with a visual indicator to gauge freshness of products with moisture content.
The company prints flexible polymer films using inks embedded with antibody-based biochemical sensors that detect mold or mildew in the packaging. The inks employed to print “Best Used By” dates change color if mold or mildew is present.
Already being commercialized in Europe for meat and poultry product packaging, the ink technology can be customized with specific antibodies to meet specific product needs -- including seafoods, fruits and vegetables. Research is under way with the University of Southern Mississippi (Hattiesburg) to develop consumer product packaging applications that could detect and signal the presence of pathogens such as E.coli, listeria and salmonella.
Seafood processor Port Graham Corp., Port Graham, Alaska, recently won a contract to supply the armed forces with smoked fish products packaged in films incorporating Toxin Guard ink technology.