Food Safety
Commitment to Food Safety
January 10, 2019
Customer Service
Why Regal Considers Customer Service Critical
April 24, 2019
Food Safety
Commitment to Food Safety
January 10, 2019
Customer Service
Why Regal Considers Customer Service Critical
April 24, 2019
Show all
0
metal detector setup

Are You Prepared for your Metal Detector Setup?

Metal Detector Setup

Critical Limit

When it comes to setting your standards, how do you set the Critical Limits?
As defined by the FDA, Critical Limit is “A maximum and/or minimum value to which a biological, chemical or physical parameter must be controlled.”  This happens at any given CCP (Critical Control Point).  This will prevent, eliminate or reduce to an acceptable level the occurrence of a food safety hazard.” So you need to be sure you know what you’re doing in a metal detector setup.
All metal detectors have their differences, but all are essentially the same when it comes to determining the CCP:

• Sensitivity, or threshold: These are the trigger points for the test sample and contaminant. So if your sensitivity is set to 1.5 Ferrous, 2.0 Non-Ferrous and 2.0 Stainless Steel 316, it should find those.  Anytime one of those size contaminants or larger passes through the aperture, the detection system should reject the contaminated product.

• Phase angle/compensation: These are the settings for the product.

Calibration to Product

1) The detector should have an automatic calibration feature to follow as a starting point. During the metal detector setup, you “calibrate,” using uncontaminated product.  Look at the signal created each time it passes through the aperture or is “scanned” by means of the display. This will display as a number or scale of led lights. When the product generates little or no effect, then we say the product is “tuned out.” That is, to say, the product itself will not trigger a reject. The term “calibration” is used only as it refers to the product’s relationship to the detector. For instance, when an audit is done, the auditor will not calibrate your detector.   He/she will be validating that the detector is achieving the expected, HAACP defined standards.

Sensitivity

2) Second, as you continue through the metal detector setup, set the sensitivity. Pass the product through with the contaminants (often in 0.5 mm increments) to find which sample size works for the product. Do this for each type of metal.  Be sure you are using Ferrous, Non-Ferrous and Stainless 316 (while use 304, 316 is the industry standard). Keep in mind that the least sensitive portion of the aperture is at the center. Test pieces should always be placed in the middle of the product when feasible.  This, ideally, is the approximatel centered in the aperture. If the sample is detected there, it will be picked up anywhere else it might appear.

Repeatability

3) Next, (in this phase of the metal detector setup) you can define the repeatability of the test.  Do this by watching in production to see if the product is consistent. Irregularity or change in the product effect will produce false rejects which will require further tuning. A minimum variance between the product and product plus test standards has to be feasible.  This is needed in order to ensure the system does not reject good product.

How OFTEN does a metal detector need to be tested using certified test pieces?

A metal detectors operation and performance, including detection and rejection of test samples, should be verified and documented on a regular basis, especially at the start of a product run or shift change. This regularity should be spelled out in the HAACP plan, but at minimum, should be hourly. In addition, whenever any settings are altered or updated, the testing should occur again. A minimum expectation for testing should be hourly.

Imagine, somewhere in the middle point between two verification tests, that the detector ceases to operate properly or at peak performance. When the test occurs at the hourly point and fails, ALL product from the last test will need to be put on HOLD and reworked after the equipment has been repaired or updated. Depending on the speed of your production line, this could mean a LOT of product set aside, waiting for another run, before it can be released to the market. In many cases, this may entail sending that product out for 3rd party testing. This is costly both in terms of product value and time. If you’re not releasing product to the market, you may be safe, but you’re not making money, either.

Industry standards and auditing constraints may prescribe the testing frequency and the proper procedure for testing. A company’s QA department usually defines those specifications. Ultimately, the higher the frequency of testing, the better. Should the equipment fail a testing sequence, quality control hold procedures will need to be initiated.  You should know or set this criteria during the metal detector setup.

Why do you get differing results for different products?

Conductivity or magnetic effect will vary from product to product. This determines where the detector is “calibrated” at the point where the signal is not displayed or impacting the reject mechanism. Gold, silver and copper are things we typically think of as electrical conductors, but salt and water in the product will affect its magnetic properties. Since all products will have one or both of these, the product effect will require attention. Product effect can behave in similar fashion as the non-ferrous and stainless standards being used, so this needs to be taken into consideration. A cold product with liquid will behave differently than a frozen product even though both have liquid of some type. Powder will react differently than solids or what appear to be solids, like gummy bears, which appear solid, but have a high liquid content.

When a detector is installed or a “start-up” is performed is the critical time to nail down all the potential issues you may have with a metal detector: the “calibration” or limiting of product effect, sensitivity (including the electrical noise on or near the production line), the achievable standards, and the repeatability. This will also include reject timing, as a reject system improperly timed will either miss the actual product needing to be eliminated and/or rejecting good product.

A company like Regal Packaging Services, (representing Fortress Technologies) with 20+ years of business and several decades of knowledge within its team is the best place to get a production line set up properly and all your questions answered.

http://www.regalpack.com/wp-content/uploads/2015/04/Manuals/TestingMetalDetectors.pdf

See http://www.regalpack.com/metal-detection-basics/

See also: https://www.ifsqn.com/forum/index.php/forum/138-metal-detection-x-ray-inspection-sieving/

Related posts

June 1, 2025

Multiscan Metal Detection

Read more
Pipeline Metal Detector
April 1, 2025

How Do You Test a Pipeline System?

Read more
Aluminum vs. Brass
September 1, 2024

Should You Use Brass or Aluminum in Metal Detection

Read more

Leave a Reply

Your email address will not be published. Required fields are marked *


✕
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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.

✕

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.