Pendulum Impact Tester is a high strain-rate test to determine the amount of energy absorbed by a material during fracture. The Impact tester involves a pendulum of known mass and length which is dropped from a known height to strike an Impact Specimen. Impact specimens are of standard or subsidized dimensions that can be found in a variety of industry standards including ASTM E23, ASTM A370, EN 10045-1 and ISO 148. Various strikers and specimen vises are available to suit all requirements of Charpy or Izod Testing. Specimens are notched using a broaching machine to specific dimensions and geometries. The energy transferred to the material after impact can be inferred by comparing the change in height of the hammer before and after striking the specimen.
Origin and Invention
Heating Shrink as it is known today can be traced back to the early post- World War II era. Scientists started to take notice of the effect of radiation on a variety of materials, including polymers, as nuclear energy programs sprang up in the United States and elsewhere during this time.
In the 1950s, one of these scientists was Paul Cook working out of Stanford University. He was especially interested in the effects of ionizing radiation upon plastics. Cook and some others found after being exposed to radiation, that some plastics took on a heat shrinkable quality.
Cook soon commercialized his discovery by starting his own company (later to become Raychem). Whilst other researchers soon followed his invention, he is largely given credit for bringing heat shrinkable materials to a commercial market. Heat shrinkable tubings and wrapping were available to the public by the early 1960s. Numerous innovations and variations on heat shrinkable products have resulted in continuous growth in this industry ever since.