Different NDT-methods and their possibility to detect defects [Adhesive bonding with quality] 

 

Table 1 Different NDT-methods and their possibility to detect defects, [Engineered materials handbook]
NDT-method *

Defect

 Manual method Ultrasonic method X-ray method Thermal method Vacuum method
Defect between adhesive and adherend X X   X  
Defect in the adhesive   X X    
Bad adhesion between adhesive and adherend         X
* The table is presented in the handbook "Limma med kvalitet" (eng. Adhesive bonding with quality), page 207, where the NDT-methods are presented in more detail.
Note: Where did the fault appear?
How severe is the fault?
Table 2 Example from the aircraft industry - Some common defect types and NDT-methods, [Saab Scania]. Reference: [Adhesive bonding with quality, page 208], where the NDT-methods are presented in more detail.
NDT-method
 
 

Defect type

 Manual method

Visual inspection 

Tapping
method
 Ultra- sonic
method		 Fokker bond tester Bonda-scope 2100 X-ray method Neutron radio-
graphy		 Thermal method Vacuum method Holography
method
Void     X X X (X) X (X)   X
Porosity     X X X (X) X (X)    
Separation/disbond     X X X   X (X) X  
Adhesive bond line too thick     X X   (X) X      
Lack of adhesive   X X X X   X X X X
Release film residuals     (X) (X)            
Porous, foam fillet* X                  
Lack of fillet* X                  
Cavitation of fillet* X                  
Fracture in fillet* X                  
Leak, outflow of adhesive X                  
* Fillet = exceeding/overflow of adhesive, pressed out at the edge of the joint.

References:

Adhesive bonding with quality - a handbook. 1994 (in Swedish) ISSN 0349-0653

Engineered materials handbook, volume 3. Adhesives and Sealants. Library of Congress. ISBN 0-87170-281-9

Saab Scania AB. Report Reg nr. TUKFF-91.330 (in Swedish)