Saturday, October 23, 2010

Metallographic Microscope

A metallographic microscope is a high power compound microscope with objectives of various magnifications on a turret that rotates them into place. Common magnifications are 100x up to 1000x. It is used for examining the metallic grain structures of heat treated metals as well as studying composite materials. A metallographic microscope is also used in metal foundries for inspection of the cast metal samples. Also known as metallurgical microscope, this type of microscope uses reflecting light that travels through the microscope objective. This is known as epi-illumination. Light in a dissecting stereo microscope is also reflected but it comes from an illumination source from the side, or sometimes is coaxial. In coaxial illumination, the light comes along the same axis as the objective by means of a prism located within the microscope head. Light enters the side of the prism and is reflected downward to the specimen. Still, the light does not travel through the objective as it does in the metallographic microscope.