For quality-conscious food manufacturers, seeing a package without any visual access to what’s inside could be worrisome … and rightly so. Does the product have deformities that were missed upstream? Is a contaminant hiding inside? These questions all come to mind, except that nowadays, bakers and snack producers don’t just have to rely on faith in the process. They have technology.
In addition to finding foreign objects such as metal, glass, bone, stones, plastics or rubber in packaged products, X-ray technology and vision systems also count the items, identify broken or missing pieces, measure the mass or weight and verify package integrity, said Brian Barr, sales manager of packaging, Heat and Control.
And defective products also can be ejected.
While both inspection systems carry out similar tasks, each have different abilities. As X-rays improve, they’re becoming more reliable with investigation as strong beams scan through the product. Vision-based camera systems detect mislabeling on a product, broken seals or missing declarations of allergens, said Miles Kroner, business manager of vision and serialization, Mettler Toledo. This minimizes product recalls, retailer fines and costly rework.
Baking and snack companies should ask themselves if there’s value to using both types of equipment on one line for quality assurance and more product information.
“Leveraging the software capabilities such as on-board diagnostics, quality-control performance verification routines, overall equipment effectiveness, image library and quality control auto-reports allows customers to put a robust quality control program around the equipment — ultimately helping them comply with audits and Global Food Safety Initiative-based standards,” said Lanel Menezes, business manager at Mettler Toledo. “The technology helps our customers further bolster the overarching food safety program, keeping consumer safety as the main priority.”
Interferences with imagery
With X-ray equipment and vision systems, image clarity is everything. And there are a variety of factors that could potentially obscure what’s really going on in an item.
“Metal foils can make it difficult to see surface defects or see through for X-ray technology,” said Joe Crompton, vice-president of robot technology, BluePrint Automation. Additionally, the size of the foreign objects and product rates can prove challenging.
Mr. Barr has noticed that glass containers are consistently tougher applications to inspect. A combination of products, packaging or potential contaminants can also be difficult for a system to read when striving for safety.
Depending on the packaging, Mettler Toledo has a variety of X-rays to do the job. For example, its X37 side beam system is designed for tall, rigid containers. Its X34 system — which will be exhibited at the International Baking Industry Exposition held Sept. 7-11 in Las Vegas — is for small packages, its X36 is for large-case products and its X38 is for pumped products. The company understands that product presentation plays a significant role and that the inspection process must maximize foreign matter detection and keep the visual appeal, said Mr. Menezes.
Mettler Toledo’s vision systems face other challenges such as consistent product handling and inconsistent code verification print quality, sometimes due to a low contrast between the code and background design.
Clear packages and monotone colors can be difficult with vision systems, noted Steve Holtschult, vice-president of technology, Colborne Foodbotics. The products should also be identical for the best results.
“The ever-changing shape of products causes unstable image recognition,” he said. “Products that are rigid and have clean lines of sight are easier to capture.”
Not only does poor image quality cause vision systems to miss tainted product, but it also can swing the inspection pendulum the other way.
“Flexible packaging poses the largest challenges, as the variability can cause false rejects due to unclear camera presentation and reflection from the vision system’s light source,” Mr. Kroner said. “Vision systems perform best when the packaging is rigid or smooth and consistent.”
And companies can’t forget that a clean machine produces clear imagery.
“Maintenance and cleaning of vision systems are as straightforward as they are fundamental,” said Andrea Bertuolo, chief executive officer and sales manager, EyePro System. “The procedures do not take long, and the parts to check and change periodically are not many but should be respected to allow for the best system performance.”
Advances provide accuracy
Despite imagery concerns, improvements in X-ray and vision system technology have created better clarity. Systems are developing to meet customers’ needs. New algorithms, for example, can compensate for distorted images, Mr. Holtschult said. Other advancements such as 3-D or time-of-flight technologies have made it easier to inspect products.
“At times, a customer is interested in pre-package inspection, and at other times a customer is focused on following final packaging, all while working to eliminate any contaminants at each critical control point,” Mr. Barr said. “We look at the various product characteristics to ensure that we can inspect, transfer — onto and off of the X-ray system — and remove contaminated products, all of which require some customization to ensure seamless installation, integration and operation by our customers.”
The ability to make equipment modifications, especially when it comes to software, is one of the biggest advances in X-ray and vision systems. Mr. Crompton said you have to set parameters for an X-ray machine or a vision system of product size and type as well as the specific defects to be detected.
EyePro System has different software for each product and different rejection systems depending on the product characteristics and distribution on the line.
“It is very important to get familiar with these systems and to use them in the first phase to acquire data on the process capabilities in order to set the right limits accordingly,” Mr. Bertuolo said.
The amount of voltage power determines the accuracy of an X-ray systems’ beam when it penetrates a package and produces an image for inspection. Mr. Menezes said operators must adjust the voltage level in legacy systems for different packaging and products; however, new systems, such as Mettler Toledo’s X3000 series, are trained to adjust automatically.
“The packaged product is passed through the system a few times in ‘teach’ mode to learn variations in production, and the software chooses the most effective voltage and amperage levels to conduct a successful inspection,” he said. “This, along with advanced detection algorithms, makes the setting of those levels very accurate and eliminates the possibility of human error.”
Vision systems also are designed with automated adjustments to account for a wide variety of product sizes, shapes and packaging designs. But Mr. Kroner said the machine also needs to be tweakable for the operator.
“An easy-to-use software interface is essential to a successful implementation of a vision solution,” he said. “If the onsite operator is not able to adjust the technology, the benefits of the vision solution can quickly fade.”
Although Heat and Control’s focus is on achieving the best analysis and detection performance, Mr. Barr said the company also is working to simplify the user experience for X-ray.
“Our goal is to provide equipment that not only allows users to get to their goal of delivering the safest products to their customers but also gives them an intuitive and an informative operational experience,” he noted. “The information reporting aspects of the X-ray inspection results is key.”
EyePro System is doing the same thing with its vision camera equipment.
“Vision systems are not just installed to inspect quality and reject defective products, thus avoiding recalls and protecting the brand,” Mr. Bertuolo said. “Our vision process control solutions are used also to provide easily accessible and interpretable information, share real data coming from 100% of the production, understand the process and improve the process capabilities and the final products delivered to the final customers.”
Baked foods and snacks need to be examined carefully before being sent out to sit on store shelves. Quality control that ensures the safety and standards of a product through X-ray technology and vision systems can verify the consumer will get what they expect and will ease the mind of the manufacturer through inspection data.