Sep 12, 2024
This term refers to a systematic examination of the physical, mechanical, thermal and chemical properties of plastics.
This makes it possible to assess their quality and suitability for specific applications. The most important test methods include tensile, compression and bending tests, hardness tests, impact strength tests and thermal analyses such as DSC and TGA. These tests help to precisely characterize the material properties and ensure that plastics meet the requirements of their subsequent application. The results of plastics testing are crucial for the selection of suitable materials and the development of new plastic products. They also enable quality control in production and the verification of material conformity in accordance with norms and standards. Plastics testing therefore makes a significant contribution to the safety, functionality and durability of plastic products.
Quality:
Tensile test on a standard test rod
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Poisson’s ratio
This glossary of plastic industry is provided by PLEXPERT Canada Inc.
Sep 17, 2024
The material constant that indicates the ratio of transverse strain to longitudinal strain when a material is deformed is called Poisson’s ratio or transverse strain coefficient.
The Poisson’s ratio describes how much a material shrinks in the transverse direction when it is stretched in the longitudinal direction. Typical values for the Poisson’s ratio for plastics are between 0.3 and 0.5.
A high Poisson’s ratio means that the material shrinks significantly in the transverse direction when stretched longitudinally. The Poisson’s ratio is important for calculating deformations and stresses in complex components and is frequently used in materials science and engineering. Its precise determination is crucial for the design of components in order to correctly predict their deformation behavior under load.
Quality:
Temperature dependence of the Poisson’s ratio for different materials.
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This glossary of plastic industry is provided by PLEXPERT Canada Inc.
Dec 9, 2021
is a tolerance specification and is found on engineering drawings to describe the position of the center of a bore or surface.
The toleranced straight line or plane must lie between two planes that are perpendicular to the reference with the set distance.
For bore centers, the axis of a bore must be inside a cylinder of the given diameter.
The cylinder axis must therefore coincide with the location of the bore axes to the given reference planes.
There are special cases where a point can be set as a toleranced element (e.g. center of a sphere).
Dec 9, 2021
or also called line profile, is a form tolerance and describes a tolerance zone which is limited by two curves (envelope lines or envelope curves).
This tolerance defines how the curvature of a part must be designed.
The measured profile line must lie at every point across the thickness of the molded part between the envelope lines running at the given distance.
The distance between the two equidistant enveloping lines is formed by circles with the specified diameter.
The centers of the circles lie on the shape specified as geometrically ideal.
Quality assurance: Profile shape line
tolerance with enveloping lines at the distance of a circle diameter of 0.09mm
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This glossary of plastic industry is provided by PLEXPERT Canada Inc.
Dec 14, 2021
This term refers to a tolerance zone which is bounded by two curves.
The area tolerated as the profile forming area must lie between two equidistant enveloping surfaces.
The spacing of these enveloping surfaces is formed by imaginary spheres with the diameter of the specified value, encompassing the entire specified curvature.
Quality assurance: Tolerated surface profile with representation of the enveloping surfaces
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This glossary of plastic industry is provided by PLEXPERT Canada Inc.
