Liquid Penetrant Testing (PT) Liquid Penetrant testing is
probably the most widely used NDT method. The test object or
material is first cleaned and then coated with a visible or
fluorescent dye solution. After a pre-selected time interval
(dwell time), the excess dye is removed from the surface, and
then a developer is applied. The developer acts like a blotter
and draws penetrant out of imperfections which are open to the
surface. With visible dyes, the vivid color contrast between the
penetrant and the developer makes the "bleedout" easy to see.
With fluorescent dyes, an ultraviolet lamp is used to make the
"bleedout" fluoresce brightly, thus allowing the imperfection to
be seen readily. With a wide variety of penetrant materials and
a custom made fluorescent penetrant inspection system, we can
provide both field and lab, high volume processing of many
different parts with both fluorescent and visible penetrants.
Dye penetrant inspection (DPI), also called liquid penetrant
inspection (LPI) or penetrant tes