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Atomic Force Microscopy
AFM is a form of scanning probe microscopy. The AFM probe has a very sharp tip, at the end of a small cantilever beam. The probe is attached to a piezoelectric scanner tube, which scans the probe across a selected area of the sample surface. Interatomic forces between the probe tip and the sample surface cause the cantilever to deflect as the sample's surface topography (or other properties) changes. A laser light reflected from the back of the cantilever measures the deflection of the cantilever, and this information is fed back to a computer, which generates a map of topography and/or other properties of interest. Areas as large as about 100 microns square to less than 100 nm square can be imaged.
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Comparison of Polypropylene Sealing Surface by AFM
Atomic force microscopy was used to compare the sealing surfaces of two components manufactured from different cavities within a multi cavity tool. One cavity produced poor seal quality whilst the other produced a good, consistent seal.
AFM images of the two surfaces are shown below:
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Figure 1. AFM image from cavity showing good seal quality
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Figure 2. AFM image from cavity showing poor seal quality
As can be seen from these images, whilst the component from the good cavity shows a relatively smooth surface, the cavity producing the poor seal quality has a rippled, undulating surface. This cavity, with a reduced tool temeprtaure produces stick/slip flow in the critical region of the sealing surface.
Source: ipolytech
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