X-ray inspection: Getting more for less
With new demand and recent advancements, manufacturers are offering more affordable X-ray inspection machines that are easier to use.
With the enactment of the Food Safety Modernization Act (FSMA), the industry is experiencing the effects of a major regulatory shift that emphasizes preventing food contamination rather than responding to it. Processors must meet mandatory preventative controls to be in compliance with FSMA, and many see X-ray equipment as a key part of a facility’s food safety plan.
“The Food Safety Modernization Act requires companies to enhance their food safety plans with tighter controls and recordkeeping in the event of an audit or recall,” says Bob Reis, lead product manager of metal detection and X-ray inspection for Thermo Fisher Scientific. “This is why X-ray is being adopted more frequently—typically at the end of the line.”
It is important to note that the wording of FSMA does not specifically require processors to have X-ray machines. However, the section of the act commonly referred to as “preventative controls” states action to eliminate or significantly reduce hazards must be taken and documented.
“FSMA requires food and beverage manufacturers to ensure their products are free of biological and chemical contamination, and physical contamination from, for example, metal fragments or stones,” says Kim Susor, marketing manager of Mettler-Toledo Safeline. “X-ray systems can support manufacturers in adhering to the principles of Hazard Analysis and Critical Control Points [HACCP].”
In addition, retailers are creating strict standards regarding contamination detection and putting more pressure on the food and beverage manufacturing industry to adopt product inspection equipment. “Walmart, for example, requires all suppliers to achieve Global Food Safety Initiative [GFSI] certification, a condition of which is the implementation of measures to minimize the risk of foreign body contamination,” observes Christy Draus, marketing manager for Eagle Product Inspection.
If major retailers aren’t openly requiring processors to use X-ray equipment, they are strongly suggesting it. “Manufacturers and their customers have increasingly sought more efficient inspection equipment to handle faster production line speeds and higher levels of inspection sensitivity, accuracy, reliability and even traceability,” says Todd Grube, manager of inspection systems for Heat and Control, Inc.
Product packaging changes may also spur a processor to make the switch from metal detection to X-ray systems. For instance, David DiPrato, CEO of Novus X-Ray based in Blue Bell, PA, recalls when a local pie company that produced its product in a paper-based package wanted to automate its production line and found it needed to switch to foil pans for the extra support.
“The company realized the metal detector it had used for years wouldn’t meet its inspection requirements,” he says. DiPrato adds that packaging technology is increasingly using metalized packaging, generally foil, which creates interference in metal detectors, but not X-ray systems, giving them a major advantage.
“Another reason for using X-ray technology is the ‘product effect’ problem metal detection has,” he says. “If the production line is running at full speed with no problems, the temperature of the product stays consistent. But if the line stalls and the product cools or warms up, especially causing a state change, such as frozen into liquid, there’s a large difference in the conductivity, which is the scientific principle metal detectors work on.” However, product temperature makes no difference with X-ray technology.
With X-ray equipment’s growing capabilities, processors are showing more interest in using it to help uphold product quality and safety, as well as brand integrity. Antoine Dodier, general manager of Loma Systems’ Canadian office, says during PACK EXPO East, at least half the company’s booth visitors had questions about X-ray equipment. “Although metal detectors are very efficient in many cases, X-ray technology is probably the most advanced method in terms of finding the smallest contaminants,” he says.
Plus, X-rays can detect a larger variety of materials such as glass, high-density plastic, rubber or even bones and stones. “X-ray inspection is now more frequently used because it combines the functions of metal detection and checkweighing with the detection of non-metallic foreign objects in a relatively small footprint,” says Grube.
The data management systems included in X-ray equipment are becoming more attractive to processors, says Draus. For example, Eagle Product Inspection machines can record and store data on conforming and non-conforming products on the line. “This information allows manufacturers to demonstrate they have taken every feasible measure to prevent contamination and enable them to trace the source of safety issues,” she explains.
While FSMA requires companies to enhance their food safety plans and keep detailed records, these records also assist in taking preventative actions and producing documentation if contaminated product makes it out into general distribution, says Ries.
In addition to helping achieve food safety goals, advanced data management systems allow manufacturers to look at multiple inspection machines at the same time to help analyze reject trends, according to Draus. [“These systems] can help manufacturers keep up to speed with how their production processes are operating and plan scheduled maintenance, minimizing operational downtime,” she says.
X-ray technology is not new to the food and beverage industry. However, it is offering processors a steadily increasing number of benefits, specifically in its ability to analyze images for irregularities.
“X-ray systems generate images where the intensity is proportional to density,” says Ries. “With modern vision algorithms, it is possible to do many things to analyze these images at high speed.” For instance, processors can not only find contaminants, they can verify presence/absence, size, position, shape, counts and some patterns.
“Besides protecting vital product safety, X-ray inspection systems can carry out a number of other important quality checks, without slowing throughput speeds,” says Susor. “They can count components or perform gross mass measurement to ensure portion control and minimize product giveaway. They can even be connected to the filling systems upstream to provide feedback control, adjusting portion sizes automatically to eliminate future instances of product over- or under-fill.”
Moreover, these systems can detect broken components like a broken biscuit or cookie in a pack. They also can make sure a box of 12 chocolates actually has 12 pieces, with each in the correct place. These capabilities ensure the product is delivered in an attractive manner, providing the consumer with the intended and expected experience.
“The systems can even check seal integrity on packs to minimize the risk of premature product spoilage and ensure products such as hamburger patties are of uniform shape and size so they don’t just look the same, they cook at the same rate for enhanced consumer safety,” says Susor.
X-rays can generally find smaller fragments of metal, but targeting the detection of less dense contaminants, such as glass or rocks in more complex products like nuts, traditionally has been difficult. However, some advancements are being made in this area.
“Thermo Fisher Scientific’s latest X-ray system eliminates foreign objects from bulk flow materials such as nuts, seeds, berries or vegetables,” says Ries. “In the past, companies that process these products have relied on sieves, magnets, optical sorters and metal detectors. But there are many well-documented cases where contaminants made it through all these lines of defense into the end product.”
The new, continuous flow X-ray system based on the Thermo Scientific Xpert platform can find and remove metal, glass and stone with a diameter of one to four millimeters. Ries says the system is designed to be used early in the process to eliminate hard-to-find objects prior to adding significant value to the end products.
Detecting contaminants earlier in the production line is a key benefit, says Mettler-Toledo’s Susor. “This not only maximizes detection rates, it helps reduce product waste, lowering operating costs for manufacturers,” she says.
Placing an X-ray inspection system upstream on the production line, where the product cross section is smaller, makes the technology more effective in detecting contaminants, says DiPrato. “In the question of what’s detectable, the first thing you have to determine is what kind of a product it is, and how much of the product will be penetrated by the X-ray beam,” he says. “Customers would like to deploy X-ray inspection at the end of the line, in cases or cartons, for economical reasons. Unfortunately, that’s probably the worst place to put the X-ray machine.” Generally, at the end of the line, the X-ray beam must penetrate a large cross section of the product, which diminishes the sensitivity of the technology. Plus, the cost of the machine is higher due to the required larger inspection aperture. Consequently, DiPrato suggests processors figure out where the cross sectional distance is the smallest, and there is little chance of further contamination.
“That’s usually at the single product package point,” he says. “If you’re making candy bars, it’s the single candy bar, not the retail box. If you’re making hamburger patties, definitely the individual patty would be better to inspect than the case. And, blueberries are best inspected in bulk flow just prior to filling poly-lined boxes.”
Since many processors have traditionally associated higher costs and more complex operation as barriers to owning of an X-ray system, some manufacturers are attempting to make the technology more affordable and easier to use. One of the biggest trends in the last few years has been the increased level of sensitivity in X-ray detectors, resulting in the use of significantly lower X-ray power.
“This means the system shielding requirements are less, the machines are safer, and the X-ray sources run cooler and last longer,” says Ries. “The algorithms to detect contaminants in images also are constantly progressing, so more subtle foreign objects can be automatically detected.”
The cost to operate X-ray equipment can be cut even further with more energy-efficient machines. For instance, the Mettler-Toledo Safeline X33 system features a 20W X-ray generator that consumes a fraction of the power of traditional 100W generators. “This significantly reduces energy consumption and cuts operational costs, while maintaining the same high detection sensitivity,” according to Susor.
Previously, when companies looked at buying X-ray equipment, they had to consider the higher maintenance and installation costs associated with it, which made ownership more daunting.
“But everyone wants an X-ray machine now,” says Loma’s Dodier. “So, we’re making the technology more affordable, not just to purchase, but also to run. We’re offering equipment that has greater longevity, as well as a new detector, which allows processors to minimize maintenance costs.”
Doug Pedersen, Sesotec’s product inspection manager for North America, says X-ray systems for general packaging lines make up roughly 80 percent of the machines being sold. “The developments are in lower cost, use smarter software and are easy-to-use machines,” he explains. “As computers get faster, X-ray systems do more at faster speeds. Improvements in X-ray tube efficiencies increase the source life and reduce the cost [of ownership]. The detector resolution is better today than it was even a few years ago; hence, we are able, with smarter software, to see things we could not see before.”
One company offering lower-cost systems is Xavis, which entered the US market last year. It sells Korean-made X-ray inspection equipment that is affordable, but comes equipped with the same high-quality software as higher-end machines, says Scott Hudson, marketing director for Xavis.
“We know our customers want a machine that is robust and can grow with their companies,” says Hudson, which is why all its Xavis FSCAN machines have a Smart Learn function, seven proprietary algorithms, seal control, fill level control, counting functions and more.
Anritsu Industrial Solutions USA has also heard from many processors that have limited their use of X-ray systems due to cost and difficult operation. “Anritsu has listened to these concerns and developed lower-cost X-ray systems and improved the overall operational platform,” says Rob Tiernay, director of sales in North America for Anritsu. All the company’s systems use HD imaging and have the same operating procedures. To allow for easier use, the software’s major component is an auto-learn process for new products that allows for quick product code registration.
Many X-ray suppliers are focusing on automation as a way to help make the user experience less difficult. For instance, Sesotec Raycon fully automatic software includes image analysis techniques to detect smaller or softer contaminants and handles varying densities.“The automatic recognition software fully adjusts filtering and setup for completely random products, virtually eliminating the need for an operator to touch the machine,” says Pedersen.
Novus X-Ray utilizes fully automatic training technology in its X-ray machines to teach what normal products should look like under the light of X-ray energy and reject everything else. A one-button “auto-learning” system pioneered by the company allows a technician to visually inspect an X-ray image that has been falsely detected and, with one button, tell the machine to ignore similar detections in the future. No further adjustments or even knowledge of how the image processing system works is required.
Thermo Fisher Scientific’s NextGuard system now offers inspection capabilities in a new way—by using easily customizable vision software. “Instead of creating an application-specific combination of vision algorithms, NextGuard product verification software allows the user to combine functions as needed from a library and experiment interactively with the software to determine if a wide range of inspections is feasible,” describes Ries. “This eliminates the need to rely on the X-ray vendor for application-specific software development and maintenance.”
Also offering new capabilities, dual energy systems improve the detection of low-density foreign objects, particularly in notoriously difficult applications such as products with uneven surfaces.
“Traditional X-ray systems detect foreign objects by analyzing dark and light areas in transparent X-ray images,” says Heat and Control’s Grube. “However, when products overlap, distinguishing dark areas from foreign objects becomes unreliable, resulting in missed detection and false rejects.”
Heat and Control’s Ishida IX-G2 X-ray inspection systems solve this problem by using a dual energy process based on medical X-ray absorptiometry. It compares the absorption of X-rays on two levels, which improves detection of thin, low-density foreign particles such as flat glass or rubber.
Eagle Product Inspection’s dual energy solution, MDX technology, discriminates materials by their chemical composition, rather than density alone. It detects problematic contaminants in products with high variations in density such as bags of salad or mixed frozen vegetables.
Anritsu DualX technology also analyzes two different X-ray energy signals at the same time. The DualX system is optimal for use in the meat and poultry industry as it is well suited for detecting low-density bone, stones and rubber, says Anritsu’s Tiernay.
Dual beam inspection systems are also available. With these systems, inspections are provided simultaneously from several different directions, which can eliminate blind spots and possibly provide a better image of the product being inspected.
“When used with cans or jars, dual beam inspection can detect slivers or shards of glass or, when the bottom of the container is not flat, find contaminants an X-ray system may miss if it only inspects from one angle or view,” says Ries.
This increased inspection capability can boost detection rates, but it does come at a cost. “Several beams have to be generated for them to work,” says Draus, “so these systems consume more energy, adding to production cost.”
Therefore, if packaging presents no potential blind spots such as foil or film flow-wrap packs, single-beam machines might be the best option to reduce operating costs. “Alternatively, manufacturers could take advantage of innovative split-beam X-ray technologies,” offers Susor. For example, Mettler-Toledo Safeline GlassChek and GlassChek PLUS systems generate a single X-ray beam that is split to produce two separate beams, combining better detection with energy efficiency. “Another innovation from Mettler-Toledo Safeline is the R50G single-beam machine that inspects the product at an angle; this solution eliminates packaging blind spots and ensures improved detection over other traditional X-ray configurations.”
With the advancements in increased sensitivity and capabilities, ease of use and lower costs of ownership, it is no wonder X-ray systems are getting more attention from food and beverage processors.
For more information:
Rob Tiernay, Anritsu Industrial Solutions USA, 847-419-9729, firstname.lastname@example.org, www.detectionperfection.com
Christy Draus, Eagle Product Inspection, 877-379-1670, email@example.com, firstname.lastname@example.org, www.eaglepi.com
Bill Klein, Heat and Control, Inc., 800-227-5980, email@example.com, www.heatandcontrol.com
Kim Susor, Mettler-Toledo Safeline, 813-549-8343, firstname.lastname@example.org, www.mt.com/pi
James Chrismas, Loma Systems, 44-0-1252-893318, email@example.com, www.loma.com
Doug Pedersen, Sesotec, 224-208-1900, firstname.lastname@example.org, www.sesotec.us
Bob Ries, Thermo Fisher Scientific, 763-783-2500, email@example.com, www.thermoscientific.com/productinspection
Scott Hudson, Xavis, 651-482-7767, firstname.lastname@example.org, www.xavis.us
David DiPrato, Novus X-Ray, 215-962-3171, email@example.com, www.novusxray.com