Principles
DPI is based upon capillary action, where low surface tension fluid penetrates into clean and dry surface-breaking discontinuities. Penetrant may be applied to the test component by dipping, spraying, or brushing. After adequate penetration time has been allowed, the excess penetrant is removed, a developer is applied. The developer helps to draw penetrant out of the flaw where an invisible indication becomes visible to the inspector. Inspection is performed under ultraviolet or white light, depending upon the type of dye used - fluorescent or nonfluorescent (visible).
Read more about this topic: Dye Penetrant Inspection
Famous quotes containing the word principles:
“The proclamation and repetition of first principles is a constant feature of life in our democracy. Active adherence to these principles, however, has always been considered un-American. We recipients of the boon of liberty have always been ready, when faced with discomfort, to discard any and all first principles of liberty, and, further, to indict those who do not freely join with us in happily arrogating those principles.”
—David Mamet (b. 1947)
“It seems to me that man is made to act rather than to know: the principles of things escape our most persevering researches.”
—Frederick The Great (1712–1786)
“The principles of the good society call for a concern with an order of being—which cannot be proved existentially to the sense organs—where it matters supremely that the human person is inviolable, that reason shall regulate the will, that truth shall prevail over error.”
—Walter Lippmann (1889–1974)