How Metal Detection Can Help Improve Processes and Performance

For many food manufacturers, the pain points fall into three connected areas. Performance, productivity, and protection. Performance means detecting the smallest metal contaminants with greater consistency, including difficult contaminants such as fine wire and swarf. Productivity means reducing product waste, limiting false rejects, removing unnecessary stoppages, and helping operators keep lines moving. Protection is increasingly about secure access, data capture, traceability and reporting, all of which now play a greater role in audits and customer requirements.

Sensitivity sits at the heart of performance, but higher sensitivity alone is not the answer. There are different ways of increasing sensitivity depending on the product. This is because in real production environments products can vary significantly. Wet, conductive, chilled, partially frozen, and metallised film products can all create signals that make inspection more complex. When a metal detector is working close to its sensitivity limit, that variability can increase false rejects, creating waste, disruption, and additional checks.

Modern metal detection systems with better performance are designed to give manufacturers more headroom plus fewer false rejects. For dry, non-conductive products such as biscuits, confectionery, sugar and flour, higher tuned frequencies can amplify the signal from smaller metal contaminants. When combined with stronger field technologies, this can make small fragments easier to identify while keeping good product moving.

Wet and conductive products bring a different challenge because the product itself can behave like a contaminant signal. This is known as product effect. Multi-Simultaneous Frequency systems and Product Signal Suppression algorithms help remove product effect, leading to a clearer contaminant signal, and creating a more accurate inspection result. A simple analogy is noise cancelling technology. Reduce the background interference and the signal you need becomes clearer. In metal detection terms, reducing the product signal makes smaller residual signals, especially potential contaminants, easier to identify. One example is the M56R from Mettler Toledo, which uses product signal suppression technology, the 3S PLUS algorithm and AI-driven machine learning to help reduce product effect in applications such as ready meals, meat, poultry, seafood, partially frozen foods, and products in metallised packaging.

The gains are not only technical. False rejects cost money. They waste good product, take up operator time, create rework or disposal costs and interrupt line flow. A manufacturer running one wet product line with a 5% false reject rate, eight hours a day (100 products/hour) for 300 days a year, with a revenue of $2 per product, could potentially save around $24,000 per year by moving from traditional single frequency technology to a Multi-Simultaneous Frequency system. This excludes any investigation costs. Actual savings will depend on product, line speed, reject rate and existing equipment, but reducing product effect can lower product and packaging waste while improving sensitivity.

Productivity also depends on how quickly people can use and respond to the system. Large touchscreen interfaces that can be operated without the removal of gloves, can aid with ease of use and save time and improve productivity. RFID login simplifies the login process making it quicker and more compliant than traditional password-based access. Diagnostic support can also reduce unplanned downtime. Software that identifies the cause of a line stoppage and guides the operator through the next step can help production recover faster. If service support is needed, QR codes can help teams access fault codes in advance, supporting a quicker response and a stronger first-time fix rate.

Automated performance monitoring routines also have a role to play, although testing requirements depend on the application and relevant code of practice. Electronic test system can improve testing consistency across multiple lines plus free up operators for other tasks.

The third area is protection. Today, inspection data is becoming as important as the inspection event itself. Individual logins support accountability, while access logs, alarm logs, detection logs, performance monitoring records, and diagnostic logs help create a stronger audit trail. Data logs can be transferred by Wi-Fi, whilst all data can be transferred directly to MES and ERP systems through OPC UA, Ethernet/IP or managed through dedicated data capture software such as ProdX from Mettler Toledo.

This moves metal detection beyond a standalone control point. It becomes part of a connected production environment, where inspection data can reveal recurring issues, support root cause analysis and help manufacturers identify where processes can improve.

For food manufacturers under pressure to reduce waste, maintain compliance and keep lines running efficiently, modern and advanced metal detection can make a measurable difference. By improving sensitivity, reducing false rejects, simplifying operator interaction and strengthening data capture and management, it can help turn a necessary inspection step into a source of better performance, stronger protection, and long-term production value.