The Application of Different NDT Processes for Automotive PM Components 2004-01-0492

PM parts, similar to those made by other metalworking processes, are not always defect free. Typical defects like cracks or larger pores are usually checked by cumbersome, visual methods with limited effectiveness. Conversely, physical effects can also be used to detect defects through the application of eddy currents, x-ray, optical methods or the measurement of resonance modes. These methods are gaining a wide field of applications in PM today.

Some methods investigate the components locally for pre-defined defects, e.g., optical, ultra-sonic or some commonly used sonic inspection systems. Other localizing methods investigate whole components, detecting locations of defects. Sophisticated integral methods allow for the inspection of the whole component. The key point is the signal evaluation. Simple analysis only allows the determination of local defects, i.e., known defects. Sophisticated methods, combined with the right physical analysis, inspect the whole component, so that unknown defects can also be found. For a cost effective selection of defect sorting, the sensing and evaluation methods need to be fast and applicable in automated rigs. Different physical methods and evaluation tactics are presented along with their advantages and limitations for selected PM engine, transmission and seat components.