Test pieces are subjected to blows from a falling striker, of specified mass and shape, dropped from a known height onto specified positions around the circumference of the test piece.The true impact rate of the batch, or production run from an extruder, is estimated.

The maximum value acceptable for the TIR is taken to be 10%.There are two test methods, such as round-the-clock method and staircase method.

It is a tester or machine for plastic materials processing.