Constraints in Penetrant Testing

Penetrant Testing

Penetrant testing is one of the most used non destructive testing methods due to its versatility and relatively cheap costs compared to other methods.

This coupled with the ability to process very large quantities of components at once in a short space of time is what makes it such a popular method.

There are however limitations and constraints as there are within all methods.

There are 3 main constraints which can slow down the penetrant testing process which are listed as follows:

  1. Pre and post cleaning and subsequent drying – before any part can be processed through penetrant testing they must first be thoroughly pre cleaned, this is to ensure that the surface of the part doesn’t contain any contaminants which would interfere with the test and potentially mask any surface breaking defects. Furthermore, to the cleaning operation the parts must then be thoroughly dried, many specifications mandate a minimum 45 minute drying operation following an alkaline cleaning process due to the ability for alkaline substances to “quench” the fluorescence of the dye penetrant potentially making surface breaking defects undetectable.


  1. Drying following excess penetrant removal – in the penetrant testing process many of the stages within the process are relatively fast and only require times such as a 10 minute dwell period or a wash off operation only lasting a matter of minutes. Drying of components however can cause a serious constrain on the penetrant line. Parts which thicker wall thicknesses or complex geometry can cause pooling and greater difficulty in drying. This can then lead to a bottleneck in the department.


  1. Developing following drying of components – similarly to the drying oven issue the developer cabinet can cause a bottleneck as parts have a tendency to remain In this area for a prolonged period.


ATH NDT as an equipment manufacturer have found innovative ways of removing these bottlenecks from the NDT department.

Our oven & developer combination units are a great addition to any existing or new dye penetrant line system and can dramatically increase the overall throughput of your penetrant line.

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