Q: How often should needle detection equipment be validated?
Validation should be frequent enough to catch a drift before suspect goods ship. A common routine is a check with test pieces at the start of each shift, after any adjustment, after a power interruption, and at the end of the run. Some factories check hourly on high-risk lines. The interval should follow the risk of the product, the machine's stability and the customer's requirement.
The check uses certified test pieces of known size, passed through the centre and near the edges of the aperture at production speed, and confirms that the alarm and the reject mechanism operate. Record the test piece size, the positions, the result, the time and the operator. If a check fails, quarantine all goods produced since the last passing check and re-inspect them, because the machine's status between checks is unknown.
Keep the validation log with the shipment records. During an audit, the log is what demonstrates control; a machine with no log is treated as unverified even if it is working correctly.