AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
Transmit 5 crack4/2/2023 The spacer thickness between the coils is normally adjusted for the optimal detection. The amount of vertical movement for the required liftoff is distributed so that the display only shifts slightly above or below the horizontal. In Figure 1, it is the movement from the null point X to point Y, which will only cause a mainly horizontal shift of the display along that distance.Įven this small distance can be a steep curve and may have to move slightly upwards before moving downwards (see Figure 2). A horizontal movement of the dot for the first 0.01 in. ![]() The signal is not a straight line but a curve, so it is important to remember that we only need a reasonable compensation for the expected liftoff variations caused by paint and fastener head unevenness. The liftoff is normally adjusted to be horizontal, as this is the conventional direction. When the probe is passed over the fastener head, an indication will be obtained similar to that of Figure 1. However, small probes are the most common choice and can be used down to 100 Hz. The penetration will increase with larger probes, and depths of 0.75 in. There are some exceptions, such as with large or magnetic fasteners and/or if the crack growth direction is at 90 degrees to the fastener row. They are rarely used for surface cracks where the fixed sliding probes typically have the advantage. Two types of scans are possible: one scan centralized over the heads or two side (tangential) scans with one scan on each side of the fastener.Īdjustable sliding probes are normally used for subsurface crack detection. This area is directionally sensitive, so the engraved (normally green) detection line must be kept in the direction of the expected cracks. The sensitive area is located in the center of the probe between the coils. They differ with the fixed sliding probe types in that they are often moved at right angles to the crack direction (the probe is turned 90 degrees) in a 90-degree scan (see Appendix). Adjustable sliding probes are particularly well suited to finding subsurface cracks in thick multilayer structures, such as wing skins. They can detect small defects in both the surface and subsurface layers. Sliding probes are the fastest method to inspect large numbers of fastener holes for cracks. With adjustable sliding probe types, a spacer is inserted between the two coil bodies. This means that the eddy currents are induced by the driver coil (transmitter) and detected by a separate pickup coil (receiver). ![]() Sliding probes are eddy current probes that operate in the reflection mode (transmit-receive). Conventionally, these probes are used in spot probing (e.g., with a ring-encircling probe or moving a spot/surface probe around the periphery of a fastener). The guidelines for adjustable sliding probes are similar to fixed sliding probes, so this application note includes some of the same instructions and details.Īs the name implies, sliding probes move over fasteners in the inspection area in a sliding motion. This application note explains how to detect fastener hole cracks using adjustable sliding probes. OEM Microscope Components for Integration.Semiconductor & Flat Panel Display Inspection Microscopes ▾.Aerospace/Wind Blade Inspection Scanners.Flaw Detectors / Phased Array Flaw Detectors ▾.Thickness and Flaw Inspection Solutions ▾.
0 Comments
Read More
Leave a Reply. |