Protective tape must be applied on a clean, uniform and smooth substrate. Correct performance of the protection film during application depends on the materials used (protective and surface type) and application conditions at the end user.

Construction Of An Ordinary Application Machine

A standard application machine consists of the following components: The position of the rolls can vary from system to system.

  • Protection film delivery system
  • Expander roll
    Guide rolls)
  • 2 Laminating rolls: Upper and lower roll

 
Guide Rolls

These rolls guide the film uniformly over the different contact points to the laminating rolls at correct angle. Their position is dependent on the position of other rolls in the application machine.

These rolls must be cleaned regularly. Dust or metal particles that have been transported from the guide rolls of the back of the protection film can cause scratches on the substrate protection film with a release treatment is especially sensitive to accumulation phenomena the guide rolls and therefore they should be cleaned regularly.

Laminating Rolls

These rolls usually consist of an iron-core covered with a thick rubber layer. The laminating rolls normally have a diameter of 200 mm, and the thickness of a rubber layer is 15mm. We advise that the rubber should have a shore hardness of 60°. Too hard or too soft a rubber; can create problems during application, The upper and lower roll should be made of the same material.

The pressure on the laminating roll can be given in following methods:

  • Cylinder method - Air-cylinders used with a pressure of 2-5kg/cm2
    In this case no adjusting according to the thickness of the material is necessary.
  • Spring cushion method - Upper and lower reels always have contact. Suitable for thin substrates and continues laminates. The rubber rolls always require periodical inspection and replacement. A non-uniform press causes wrinkles of the film and inclusion of air-bubbles.

 

 

Protection Film Delivery System

The protection film roll will be put onto an iron shaft (30 to 60 mm) which will be selected by the weight of the protective rolls) to be used. This shaft will be provided with tapered metal fixtures to avoid slipping of the Protective paper core.

The shaft should be able to:

  • Rotate freely
  • Brake effectively
  • Fine adjustment of the crossing axes to adjust the distance of the delivery system up to the laminating roll
  • Width adjustment (transfer adjustment without moving the guide for the substrate)

 

Expander Roll

The expander roll eliminates the slack and wrinkles of the plastic film by reducing the tension length-wise direction of the film.

The body of the roll rotates in arc form and spreads uniformly the tension imposed on the film. It absorbs the slack of the film and avoids wrinkles in the film during application.

The optimum effect of the expander roll will be obtained if the roll is properly installed on the machine. The film should make a wrapping angle of 10° to 30°. Then the roll guides the stack from the concave part towards the convex part.

The effect of the expander roll will be negligible if the distance between the roll and the press a roll is too long. This distance should be as short as possible to maintain the effect of the expander roll.

The best way of adjusting this expander roll is by testing on the machine.

 

Trouble Shooting

Wrinkles In The Laminated Film

Wrinkles all over the sheet can be caused by:

  • Deviation in the parallelism of the rolls in the machine
  • Too low a brake tension of the protection film

Wrinkles in the center of the sheet can be caused by:

  • Wrong adjustment of the expander roll
  • Too high brake tension of the protection film
  • Too much pressure on the sides of the laminating roll

Wrinkles at the side of the sheet can be caused by:

  • Deviation in the parallelism of the rolls.
  • Failure in the adjustment of the delivery roll

Entrapped Air

Entrapped air all over the sheet can be caused by:

  • Pressure on the laminating rolls too weak
  • Improper rubber hardness of the laminating rolls
  • Low temperature

Entrapped air in the center and at the side of the sheet can be caused by:

  • Rubber of the laminating roll is worn out

Protection Film Brakes
Too high brake tension or a very low temperature.

Width Shrinkage Of The Protection Film
Brake tension is too high

General Precautions Using Protective Film:

  • All rolls (Protective film delivery, expander. guide and laminating rolls) should be in perfect parallel position.
  • Never use an expander roll as a turn roll
    The effect of expansion will be lost, and the roll will only have a negative effect on the film behavior.
  • Avoid putting too much tension on the protection film. For instance, by:
    Application speed is too high
    Too much brake of the protection delivery system
    A wrong position of the expander or guide rolls