Monday, May 29, 2017

May 29, 2017 Corona Metal Belt or Pinning Belt

This is another metal belt application to support film sheet forming.
Conductivity of stainless steel works here.
Please refer to the illustration below.
Meted plastics goes out of T die and falls on the cooling roller.
Pinning system is working here to transport plastics smoothly from T die to the cooling roll so as to avoid fine air bubbles, thickness deviation and degrades of transparency.  
In this pinning system high voltage is applied to a metal belt.  Through this metal belt a positive charge covers plastics.
Whe the cooling roller is set negative, thin plastics is attached to the cooling roller instantly and plastic film is formed.

Pinning system becomes more effective when a metal belt is thinner.
Tungsten wire is often used.  Its thickness is 1.5 to 2mm or 0.06 to 0.08 inches.  When roller width is quite long, this wire sags.
To avoid slack tension is appled, then the wire may be broken.
When it comes to metal belt, thickness can be 50 micron or 0.002 inches.  Yet by additional width metal belts stand much tension.
Metal pinning belt is wound on a reel and delivered
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