Robust direct current potential drop method to inspect cold pressed green bodies

The basics of the direct current potential drop (DCPD) method is presented. It is applied to studies of pressing defects in green bodies made of iron based powders. Three types of bodies are studied: rectangular bars, two level L shaped bodies and a multilevel industrial body. It is found that by using ratios of potential drop (PD) between defective and defect free areas of a body the method becomes more insensitive to disturbances. For this purpose a five electrode probe has been designed. An analysis of the statistical scatter indicates that the DCPD method is more suited to find the correct press settings than to look for defective specimens under production.