The Dog Hair Experiment

At Microscope World we are curious and love viewing different specimens under the microscope. The microscope expands the world we live in. Using a metallurgical microscope with reflected light, we took a look at some dog hair.

Image of dog hair was captured at 200x magnification using the ML7100 metallurgical microscope, a c-mount adapter and the DK3000 microscope digital camera.

400x Magnification.

A metallurgical microscope, such as the Meiji MT7000 series, allows viewing of objects that will not allow light to pass through them. A metallurgical microscope is used when a stereo microscope will not provide enough magnification (generally when you need to see micron size particles). Metallurgical microscopes look similar to biological microscopes, but a major difference is that the objective lenses allow light to shine down through them, providing plenty of light for a crisp clear image, at a high magnification.

Viewing Metal Under A Microscope

Viewing metal through the microscope can be tricky. Not only does the surface reflect light and sometimes cause hot spots in photographs, but many times the metal is not a flat surface. When viewing items with uneven surfaces at a high magnification, it's important to keep in mind that you won't be able to have the entire object in focus at the same time. This is because the depth of field decreases as magnification increases.

Metal can be viewed with either a stereo microscope or a metallurgical microscope. Stereo microscopes typically provide about 10x-50x magnification. A metallurgical microscope provides much higher magnification of 100x, 400x and sometimes 1000x. In a metallurgical microscope the light comes down through the objective lens to ensure the specimen is illuminated.

This metal slotted gear was captured using a 150w halogen dual pipe illuminator and a SMZ-168 stereo microscope at 40x magnification. Notice how parts of the gear are not in focus because the gear does not all lie on the same flat plane.

Metallurgical Microscope for Measuring Plastic Layers

Microscope World recently helped configure a microscope system for a customer who needed to measure the thickness of layers in a very thin piece of plastic (about 0.064mm). The customer wanted a system to perform quality control.

The thin piece of plastic was placed between two slides to hold it vertical beneath the ML7100 metallurgical microscope. The Moticam MC2300 camera was mounted on the trinocular port with a 1.0 c-mount. The microscope magnification was 400x, but because the setup involved a camera with a 1/2" chip and a 1.0 magnification c-mount, the camera's effective magnification was closer to 700-800x.


After capturing the plastic layers image, the Motic Images software (included free with all Moticam cameras) was used to measure each layer of plastic.

This image shows the four different layers of plastic along with their corresponding measurements in microns. The ability to quickly capture an image, make measurements and determine if a layer was the correct thickness allowed this customer to maintain quality control on their production process.

Metallurgical Microscopes

In manufacturing metals, it is often important to be able to find flaws in the metal prior to final production. However, the standard biological high power microscope will not allow you to view metals because light comes from beneath the stage and will not shine through solid objects.

The two images above were captured using the MC2000 microscope digital camera on a National Optical 420T stereo microscope. These images were captured at 30x magnification. In order to view scratches or minor flaws in metal, a stereo microscope works well.

In more advanced instances, when more magnification is required a metallurgical microscope is best. The image above was captured with the Meiji MT7100 metallurgical microscope at 200x magnification. The metallurgical microscope is similar to a biological microscope, in that it has high power objectives. On a metallurgical microscope however, the light shines down from inside the objective directly onto your specimen, allowing you to view opaque samples at high magnification.