Issue link: https://www.e-digitaleditions.com/i/1371139
34 May/June 2021 Tablets & Capsules Detector not working properly We have learned through the years that metal is often missed because the metal detector has been shut off, was improperly set up, or has a problem with its electronics. Use the following strategies to remedy these issues. Verification. Verification is the process of proving that a metal detector meets its sensitivity requirements. This is accomplished by challenging the detector in a repeatable manner using a certified metal sphere at a predetermined time. Verification is most often executed daily. A correct test protocol requires the certified sphere to be placed on the product. This is critical, as some products may impact the detectability of certain metals, especially stainless steel. This is often overlooked, and many oper- ators simply place the metal test sphere in or through the detector's aperture without the product. For most third-party audits, testing without product will result in noncompliance and could allow metal to pass undetected during production. Certified test pieces are readily available and should include a certification number that corresponds to a cer- tificate of compliance. The certificate, which confirms the sphere size and metal composition, is essential to a sound metal detection program. Validation. Validation is the process of authenti- cating the metal detector to ensure that the equipment meets verification requirements. For instance, if your metal detector has been verified to detect a 2-millimeter stainless steel sphere, you should validate these results (typically on an annual basis) using a third party. Service companies that validate equipment should provide the user with a certification letter and a sticker to be placed conspicuously on the equipment. Documentation is not limited to third-party validations. A sound program must also include recordkeeping. It is not enough to say that you are verifying your equipment; you must be able to prove it. This is much easier if your detection system features an event log for recordkeeping. Despite having policies in place, many companies don't regularly verify or validate their metal detectors, some- times with disastrous consequences. You can overcome this shortfall by using a smart detector with verification scheduling that prompts operators to test the detector at predetermined intervals. If testing does not occur, the detector can signal a warning alarm and, eventually, trig- ger a fault alarm. To identify problems with a detector's electronics, look for a detector with a continuous diagnostics feature that monitors the machine's critical parameters and trig- gers an audible and visible alarm if a problem arises. Orientation effect If the equipment is operating at peak performance and has been verified but still allows metal to pass undetected, the reason could be a phenomenon called the orientation effect. The orientation effect relates to the alignment of metal as it passes the metal detector coils and is most Photo 2: Static buildup occurs on metal detector conveyor systems installed on packaging lines due to plastic-to-plastic contact between the belting and slider bed. Photo 3: A metal detector's aperture height and width determine the detectability of needle- or wire-shaped fragments. Photo 1: Static buildup often occurs when a detector is placed at a tablet press discharge outlet, which can lead to false trips and decrease the operator's confidence in the detector.