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June 22, 2023


Fortress Technology’s automatic testing solution has been deployed by one of the largest international suppliers of frozen retail, wholesale and food-service potato products. Ensuring the ultimate product integrity and premium quality from farm-to-freezer-to-table.

One of Fortress Technology’s longest-standing customers has installed more than two-dozen of the firm’s highly sensitive Stealth metal detectors. Each equipped with customised reject conveyors and Halo Automatic Testing.

Producing everything from French fries to hash browns and onion rings, alongside scales, shakers, vibrators, graders, baggers, open bag detectors, case packers, sortation conveyors, palletisers and wrappers, located towards the end of multiple processing lines are a number of highly-sensitive Stealth metal detectors. Each providing a final and robust quality check.

Every hour, each metal detector automatically performs up to nine machine validation tests – equating to 180 or more repeatable tests on multiple SKUs and different-sized bags of French fries, ranging from 225 grams to 9 kilograms. The deployment of Halo Automatic Testing ensures tests are not skipped. The solution also helps to minimise bags of frozen fries being split open to insert test wands, and consequently good product being damaged and wasted. Additional engineering safeguards also ensure quarantined metal-contaminated products are not re-introduced to the upstream processing line.

180 inline machine tests per hour

Testing the performance of conveyor metal detectors is typically done manually. However, the challenge for an operation of this scale is dedicating the resource and time to conform to multiple QC testing criteria set by suppliers and switching between multiple product SKUs. Especially on high-speed processing lines operating at 150ppm with a frozen product range comprising multiple smaller consumer-sized bags to restaurant-sized bulk packaged bags of French fries.

Simulating real production conditions, Halo enables the frozen fries processor to program and conform to every customer’s performance verification testing program. Including independently testing all three metals in the leading, trailing and middle of product bags – a request stipulated by a fast food chain.

‘Product effect’ was the main rationale for these additional checks. The reason being is that in bulky frozen products weighing up to nine-kilos, performing just one test could result in high levels of false rejects. This not only distorts results but could lead to potentially high volumes of good product being wasted.

“By testing all three metals in three positions ensures the metal samples are not being masked by the product in any position and also confirms that the reject system is tracking correctly. This is especially important in frozen bulk products when the characteristics might change due to slight thawing during the inspection phase,” clarifies Fortress Europe’s Commercial Manager Jodie Curry.

Adapting on-the-fly for faster ROI

Switching and adapting to different test routines is equally straightforward, reports Jodie. For customers whose COP standards only require one pass of each metal sample hourly, or at the start and end of daily production, the metal detector’s infeed sensor picks this up. Communicating  with Halo to perform the verification tests aligned to each product SKU and inspection standard.

Each production line will only halt if the metal detector performance test or reject check fails. To assist with audit traceability, each individual metal detector automatically captures and saves all the data. Quality personnel can call up this digital data for a documentation review whenever it is required and extract reports via USB. Providing a reliable machine performance and due diligence audit trail.

To ensure quarantined rejected products are never reintroduced to the processing line, Fortress also added several extra failsafe features. This included equipping each reject bin with magnetic locks and issuing controlled security card access to authorised personnel only.

The reject bin automatically unlocks for any products rejected during the Halo test, enabling personnel to move the bags back upstream to be re-inspected. However, to distinguish between a genuine contaminant rejection and product isolated during the Halo performance verification test, the metal detector bin door automatically remains locked if a reject was already present.

Using Halo on conveyor, gravity or pipeline systems as prescribed can result in huge operational savings, notes Jodie.

At this specific processing factory, Fortress moderately estimates a payback of less than several months on the original investment. This factors in the combination of eliminating human errors, eradicating workforce safety risks, labour savings and reduced product waste. Meaning that each Stealth metal detector equipped with Halo for this frozen fries supplier has already potentially paid for itself more than 30-times over!