Food Safety Principles
4 Critical Principles of Metal Detection
July 1, 2023
Quality Control
Quality Assurance and Quality Control
September 1, 2023
Food Safety Principles
4 Critical Principles of Metal Detection
July 1, 2023
Quality Control
Quality Assurance and Quality Control
September 1, 2023
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Ceramic Balls

Ceramic BallsUnderstanding Ceramics and X-ray

One of the common contaminants companies are looking to remove from a product is ceramics.  At Testrods.com we offer two types – AL203 and ZrO2.

AL203 stands for Alumina Oxide.  “Aluminum Oxide (Al2O3), often abbreviated as Alumina, is one of the most popular fine ceramic material families worldwide. Encompassing a range of grades – characterized primarily by purity – coarse and dense alumina is renowned as one of the greatest materials in terms of price-to-performance ratios. Aluminum Oxide ceramics can subsequently service one of the broadest industrial cross-sections of any oxide ceramic on the market.”1

ZrO2 stands for Zirconia Oxide (or just “Zirconia”).  “Zirconia (ZrO2) is unique among the fine ceramic oxide group due to its exceptional fracture toughness and thermal expansion properties. As a result, zirconia ceramics are widely used as a specialist solution in hard-wearing and high temperature applications. ZrO2 ceramics come in a range of grades and formats to satisfy the extreme requirements of these demanding markets.”2

In X-ray inspection systems, it is always critical to know the density of the material you’re hoping to find and reject.  Since x-ray inspection is based on product density, you’ll need to understand the density of the expected contaminant.  In a nutshell, considering that water has a density of 1.0g/cm3, you can expect that anything with lower density (anything that floats) will be extremely difficult to find.

  • AL203 has a density of 3.9g/cm3, while
  • ZrO2 has a density of 6.0g/cm3

It might even be worth an investment in a densitometer to determine which kind of ceramic contaminant test piece you should be using in daily testing.  Without that knowledge, you may be completely missing the type of ceramic you’re hoping to capture.  For instance, if you choose to use ZrO2, you are not likely to capture the AL230, which is less dense.

To “play it safe,” you may want to use the less dense AL203 so you are certain to capture the greater density ZrO2.  That may mean, however, that you get false rejects based on the density of your product.  Having the specific numbers at hand (determined by a densitometer) would be very helpful. And while a good densitometer can be an investment of thousands of dollars, it may be the best investment you make in quality assurance.

“Alumina Ceramic (AL203) is the most widely used fine ceramics material. This material has superb material characteristics such as high electrical insulation, high mechanical strength, high wear and chemical resistance.”3  In fact, it is “used in the following areas, among others: Heavy-duty forming tools, substrates and resistor cores in the electronics industry, tiles for wear protection, thread guides in textile engineering, seal and regulator discs for water taps and valves, heat-sinks, protection tubes in thermal processes or catalyst carriers for the chemicals industry.”4  

ZrO2 is used for “has the highest strength and toughness at room temperature of all the advanced ceramic materials. The fine grain size allows for extremely smooth surfaces and sharp edges.  Applications include scissors, knifes, slitters, pump shafts, metal-forming tools, fixtures, tweezers, wire drawing rings, bearing sleeves and valves.”5

So given the wide range of applications for these 2 ceramics, you can expect that one of these or both should be in your cadre of ceramic test pieces.  X-ray inspection, at times, seems to be as much of an art as it is a science.  That is why getting all the statistical information you can is important to your approach and setting the demands of your HACCP plan.  A solid quality assurance team, using the right equipment and understanding the right contaminant test piece can be the best means of protecting your consumer and your profit as well.  Here’s a list of the contaminants we offer and their densities:

  • POLY-PROPYLENE 0.9 g/cm3
  • NYLON 1.1 g/cm3
  • RUBBER – EPDM 1.14 g/cm3
  • RUBBER – BUNA 1.2 g/cm3
  • PVC 1.41 g/cm3
  • DELRIN 1.42 g/cm3
  • RUBBER – VITON 1.85 g/cm3
  • TEFLON 2.2 g/cm3
  • QUARTZ 2.2 g/cm3[/one_second]
  • BOROSILICATE GLASS 2.23 g/cm3
  • SODA-LIME GLASS 2.5 g/cm3
  • ALUM 2.7 g/cm3
  • ALUM (BONE) 2.7 g/cm3
  • CER (AL203) 3.7 g/cm3
  • CER (ZRO2) 5.6 g/cm3
  • SS 316 7.82 g/cm3
  • FERROUS 7.85 g/cm3
  • NON-FERROUS 8.48 g/cm3

As you develop your Food Safety Plan, consider what types of contaminant you may want on a card or in a test piece.  Many of our customers choose to buy a multi-card.  We offer cards with whatever type contaminant (above) you need in a host of sizes.  Our most common card is a thermoform version with 24 contaminants comprised of:

  • 0.6, 0.7, 0.8, 1.0, 1.2, 1.5mm Stainless Steel 316 –
  • 2.0, 3.0, 4.0, 5.0, 6.0, 8.0mm Ceramic ZRO2 –
  • 2.0, 3.0, 4.0, 5.0, 6.0, 7.0mm Soda-Lime Glass –
  • 3.0, 4.0, 5.0, 6.0, 7.0, 8.0mm Rubber

We have manufactured cards with as many as 100 contaminants, and you can design your own card based on the needs of your product, your production line, your HACCP plan and any regulations that apply to your company.

We’re here to help you ensure that your product, the one you put in the marketplace, is as safe as possible.  We consider ourselves an extension of your food safety program.  Contact us at: (866) 691-8560 or email testrods@testrods.com or order online here at testrods.com.

  1. https://www.ceramicsrefractories.saint-gobain.com/materials/alumina-al2o3
  2. https://www.ceramicsrefractories.saint-gobain.com/materials/zirconia-zro2
  3. https://www.ortechceramics.com/creamic-materials/alumina-ceramics/
  4. https://www.ceramtec-industrial.com/en/materials/aluminum-oxide

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Floatable Thermoform Test Cards

Some applications involve large tubs, vats, or some other type of product travel where it would be nice to have a test piece that floats. Once again, our thermoform cards provide the simplest solution. We simply insert some type of structure that forces the thermoform card to retain air, which, of course, is what makes it float. We have also manufactured floating rods, which are more difficult because there is less space to close in enough air to make the rod float but is doable.

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We took an ordinary plastic “chip clip” as defined by the customer and embedded the contaminant into the clip. The clip can be attached to the product on the line without damaging or opening the product for testing purposes.

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Bone is a difficult contaminant to find because it can vary widely based on the size, age, and calcium content (as well as feed used) of the animal. After working with several customers, Regal Packaging Services offers Pork, Beef and Chicken Bone Simulate. We have a small range of sizes at a variety of depths to simulate whatever you might expect to find in the product. Our recommendation (assuming your x-ray has visual display) is always to start with a multi-card. Using a multi-card gives you an easy way to test several sizes and depths to determine what matches the bone you’re using. Once you’ve made a comparison, testing the card against the bone you’re looking for, you can purchase a card with a single contaminant for regular testing.

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This small pill shaped test piece is used in a system with a vacuum tube that shoots the test piece through the aperture and returns it to the “home” base. Your system may never be like it, but the point is that we can make a customized solution no matter how unusual or impossible it might seem.

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As you may have seen in some of the other thermoform card descriptions, we can put nearly as many seeds as you can imagine on a single card. Pictured here you will find a wide variety of configurations and contaminants. Just let us know your specs: size of the card (up to 8” x 8”) along with size and type contaminant(s) and we’ll get you a quote as quickly as possible. Working with a multi-card is especially helpful when you are looking for multiple types of contaminants or when you want to determine what size of the same contaminant you are able to detect. In that event, once the size is chosen, you can order individual card(s) for regular, standard inspection and detection.

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There are a wide range of applications that require a test piece much longer than our standard 5” or 6” Testrods. We can make up to 3/8” x 34” or 1/2” x 34” rigid test pieces which can then be extended well beyond that length with a “handle” made of acetal cylinder larger than the 3/8” or 1/2” extension. In the photos, we used a 1” x 24” cylinder handle with a 3/8” x 24” inch extension.

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Test pieces can be made in a variety of sizes and given a pointed end in applications that require the contaminant (metal) to be inserted into a food package such as sugar or some other soft packaged food product. This allows the metal to reach the center of the aperture.

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Double-End Test Whips are also available, with metal in both ends. One consideration is to make certain that the whip is long enough to keep the metal on the non-testing side of the whip outside the metal free zone of your detector. If you insert, for instance one end of a whip with 2.0mm and 3.0mm Ferrous, you need to make certain that the 2.0mm metal doesn’t affect the detection of the 3.0mm metal (and vice versa). If the 3.0mm metal is inside the metal free zone, then the detector will be reacting to the 2.0 as well as the 3.0 as if they were combined.

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Multi-seed laminate test cards are designed for seeds 4.0mm or less. Multi-cards are useful in x-ray inspection to determine what sizes and types of contaminants your system can achieve. They can be especially useful in temperate environments and applications. If your application is rugged or wet, or your standards are larger, we recommend our thermoform multi-cards.

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We can simulate a variety of packaging in an application where you need the test piece to mimic what is traveling down the production line. In this case, we manufactured a clear “package” with the seed inside. With this method, the customer is able to reject the container appropriately, and, in the event the package is not rejected, it is easily seen by the line worker for manual removal.

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There are two types of “candy bars” pictured here – one similar to a flat candy bar and the other in a custom, near perfect copy of a candy bar. Since we’re now able to produce many variations using colored material, the copy was made in red (Fe), green (NFe) and blue (SS 316). We have the equipment to accomplish nearly anything you can imagine, and these kinds of designs are proof positive.

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Need a test piece that looks and handles like chicken nugget? We can do it. Interestingly enough, in this situation, our first version for the customer left too much “void” in the hole where the metal was placed. Given the sensitivity the customer system was using, the void had the effect of causing false positives. We were able to minimize that hole and supply the test piece with almost no void. It’s an example of how we can work with you before, during and after manufacturing to ensure all the specifications were met.

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Our standard acetal card is 2 1/4"x3 3/8,” but if needed, we can cut that size down to as small as 1 1/4” x 1 1/4” (with limited engraving). If a larger card or a card with multiple seeds is needed, see our Custom Shape-Size Blocks and Tablets.

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This distinctive test piece was created to mimic an actual hamburger patty. The customer supplied photos of the raw product, which we were able to reproduce and then we placed blue glove contaminant. Using this configuration, the customer was able to determine what size piece the vision scanning system could detect with the raw burger as the background. Had they simply used a blank card with the glove, the system could easily have achieved contaminant rejection, but they needed to be sure the system could “see” the blue against the product itself.

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A card with 100 seeds in a 10x10 configuration is used to place beneath whole chickens on a production line. This gives the x-ray system operator the ability not just to see IF the equipment can detect the metal in the card, but also WHERE the equipment can detect it. If there is a problem, the operator (or company) can make any changes necessary to achieve the end goal – safe chicken in this case. This card really highlights another valuable facet of our thermoform cards.

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In this scenario, a company processing sugar needed to have a “bag” simulated with the same weight in order to accurately fall through the reject mechanism. A lighter test piece had the risk of passing over the reject mechanism.

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Our standard cubes are 1” and 1.5,” but we can also manufacture other sizes if needed. The cubes shown here are 1/2" in dimensions. Cubes can be helpful in applications where a ball or cylinder may bounce or roll away during testing, making their retrieval difficult, or, in some cases, present a hazard to the product or production equipment.

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This is a test piece that is dropped into a bottle. It’s designed so that the metal appears in the center of the aperture when testing the metal detector. In addition, the round stop makes the test piece easily removable after testing.

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Hexagonal Shaped test pieces can be very useful in places where a cylinder or ball might roll or bounce around a production floor whether dropped by a line worker or ejection from a reject mechanism. Hexagons are similar in weight to the 1inch cylinders without having the smooth, rounded cylinder edge.

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Our customer in this plant needed a test piece with a thickness less than 5.0mm. Because we have the capacity to customize sizes and shapes, we were able to mill down a product that met their specifications. That’s always our goal, meeting the specs you need for your product, testing environment and contaminants.