Sixteen-Eleven, Inc. - Reciprocating Machine Vibration Analysis

Evaluation of Reciprocating Machinery - Punch Press

On the right, a time wave shows the response of a
punch press during operation. The peaks at the bottom
of the plot exhibit a split peak, indicating the amount
of backlash in the main press bearing. As the tool
contacts the part, an initial negative peak is created.
A second small peak is created in the positive direction
as the tooling pierces the part, with a final negative
peak at the completion of the stroke. Because punch
presses are varied in structural responses and tooling
designs, the amount of backlash may be different for
each setup.

Time waves are the raw or unprocessed form of the vibration data, before
it is transformed into spectral data. Time data contains vital information
about rotor dynamics and reciprocating processes that are not easily
determined by FFT (spectral) analysis.