A plastometer is a device which measures properties of plastic materials. There are a number of variations on the design which can be used to explore different properties and which provide measurements in different scales. Plastometers are carried by companies which stock supplies for materials testing and plastics research, and they can vary considerably in size, precision, and cost. Some training is usually required to operate the device safely and reliable.
One use for a plastometer is to provide measurements of flow properties. In this type of plastometer, known sometimes as a rheometer or extrusion plastometer, the material being studied is subjected to force and the response is measured. This device can be used with plastics in a fluid state, such as molten resin used in casting. The plastometer can provide information about the material which will be used to grade it, determining what kinds of projects it can be used for and confirming that the material is of consistent quality.
The term "plastometer" is also used to describe a device which can measure hardness in plastic materials, especially rubber. In this case, the device uses pressure to indent the material, and then the penetration depth is measured. Hardness is an important property to be able to measure, as it may influence how and where various materials can be used. For example, rubber rollers on printing presses need to have a carefully calibrated hardness to ensure that they function properly.
In the development of new plastics, plastometers are used for grading and to establish baseline information about the properties of the material. A plastometer can also be used during materials testing for new and old products alike. Materials testing is used to confirm that a material conforms with a safety standard, and to establish tolerances for new materials. Likewise, plastometers can be useful in forensic examinations of plastics after an incident has occurred, and in quality control to keep products consistent.
Plastometers are usually used in a controlled environment and they are routinely calibrated to make sure that they continue to function properly. Reliable and standardized performance is critical to ensure that the measurements are consistent and accurate. Many companies will handle calibration by request, either sending a technician to a lab or having the tools sent back to their facilities for calibration sessions. In addition, the technician who maintains the device can also recalibrate it periodically, following directions established by the manufacturer.
