DS500 Density Measurement System for Polyethylene – An award winning design

The DS500 was originally developed by Tecrad Corporation in 1986 for which it won a prestigious I-R award in 1987. This international competition recognizes the 100 most innovative and unique product developments of the past year.

The award is among the highest honors granted in the field of applied research and development. Its ultrasound technique was approved and documented by the ASTM under the designation D4883. It accepts as test specimens compression-molded plaques prepared as per document ASTM D4703 which superseded document ASTM D1928.

Theory of Operation

The DS500 system uses an acoustic method for determination of density. This is possible due to the nature of polyethylene which can be viewed as a composite where high density crystalline regions are embedded in a low density amorphous matrix. The degree of crystallinity determines the density of the material. The amorphous and crystalline phases show very distinct behaviors to the propagation of ultrasound. From this it can be understood that the propagation characteristics in the composite will depend on the degree of crystallinity. The DS500 system provides a measurement of crystallinity which directly correlates to density.