Based on your previous focus on the operation background of using a dial indicator to test the coaxiality of an LVDT sensor in a hot runner scenario, the core key points of reference calibration are as follows:
Reference Rigidity Requirements: The magnetic base must be attached to the rigid moving body of the hot runner needle valve, not fixed to the LVDT itself or easily deformable parts, to avoid the reference introducing detection errors due to probe wobbling.
Indicator Head Contact Requirements: The dial indicator probe must be perpendicularly attached to the smooth outer circle of the LVDT probe, pre-pressed for 1-2 turns, and then zeroed to avoid reading deviations caused by probe slippage or tilted contact angle.
Rotation Operation Requirements: The probe must be manually rotated at a constant speed throughout the entire rotation, without causing the base to shift. A complete rotation must cover the entire circumference to ensure the maximum radial runout value is captured.
Reference Traceability Requirements: The movement axis of the needle valve must be the sole reference, not the unmachined surface of the LVDT mounting base, to ensure the reference for coaxiality testing is completely aligned with the actual movement trajectory. These key points are the core of ensuring the accuracy of dial indicator testing and can avoid more than 90% of the errors in benchmark testing.
