Turntable stretch wrappers are a type of ''automatic'' and ''semi-automatic''
stretch wrapping system. A load is placed on a
turntable
A phonograph, later called a gramophone, and since the 1940s a record player, or more recently a turntable, is a device for the mechanical and analogue reproduction of sound. The sound vibration waveforms are recorded as corresponding phys ...
, which rotates relative to the
film roll, which is housed in a carriage attached to a vertical "mast" on which it may move up and down.
Information
In the simplest turntable systems, stretch is achieved by rotating the load at a speed in which the take-up demand on the load surface is faster than the rate at which the film is allowed to be fed, being limited by a brake system.
More sophisticated systems also ''pre-stretch'' the film before wrapping by means of fixed/variable
gear ratio
A gear train or gear set is a machine element of a mechanical system formed by mounting two or more gears on a frame such that the teeth of the gears engage.
Gear teeth are designed to ensure the Pitch circle diameter (gears), pitch circles of e ...
s or other, even more sophisticated means, such as hydraulic ratios which can better take advantage of film "sweet spots", improving performance and film savings.
References
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Packaging machinery