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Issues Of Heat Shrink Film And Their Solutions

2019-05-28

LIN-YANG-Issues Of Heat Shrink Film And Their Solutions

When you are shrink wrapping products with heat shrink films, you will realize it is accompanied by various issues. Various terms are used to describe the issues of shrink wrapping, which we will inform you more about them. Such issues are obvious ones, and solving them is easy just by having the machine setting adjusted. You can be required to adjust the temperature, conveyor speed, and air velocity of the tunnel.


Their perforations quantity and size have some effects too, depending on the speed of forming the balloon and the speed it uses to collapse when there is a shrinking film. You should analyze the rate of air escaping from the film so you can come up with packages that are best looking. You can start by making the empty package onto the sealer having air in it then squeeze the air to confirm if it has holes for escaping. You can then individually pull each seal to confirm if they are very strong since weak seals will give you poor shrink. The strength of seals depends on pressure, temperature, and time. The film should also be relaxed so you can avoid getting weak seals. Below are some issues associated with heat shrink films packages and the way you can solve them.

 

Heat Shrink Film Issues And Its Solutions

 

1. Dog Ear

 

Most shrink wrappings experience the problem of dog ear, especially in the retail stores. The dog ears are protruded in a triangular shape in the packaging corner that shows there is no shrinkage. They mostly happen in large areas that have excess film amount before completion of shrinking or in corners.

 

Causes:

 

•  Large shrink bag

•  Improper heat amount

•  Loud products that have many perforations located in the wrong places

•  Weak seals or many perforations which allow easy escape of air

 

Solutions:

 

•  Adjust tunnel temperature at the monitor package shrink

•  Use a tighter packaging bag before shrinking

•  Adjust perforations or add some hole punches

•  Reduce conveyor speed at the tunnel

•  Increase the air velocity of the tunnel

•  Correct perforation amount.

 

2.Fish Eyes

 

They are oval and round patterns being formed on the package due to poor shrinking and they make the package seem unprofessional.

 

Causes:

 

•  Less heat

•  Wrong air velocity

•  Bad seals or many perforations

 

Solutions:

 

•  Adjust heat temperature to the required amount

•  Ensure heat source offers required air velocity

•  Reduce the speed of tunnel conveyor

•  Use a lighter bag size.

 

3. Crow’s Feet

 

They are simply wrinkles found at the wrapping package corner. They always appear with dog ears.

 

Causes:

 

•  The product corners can have excess films

•  Less heat

 

Solutions:

 

•  Use a thinner shrink film

•  Lower available air holes or sizes

•  Lower air being evacuated at the heat shrink film container

•  Use a smaller bag

 

4. Angel Hair

 

They are thin shrink film strands between the sealed end and the product that is being sealed at the wrapping film. When it is large at the package, there is no attractiveness.

 

Causes:

 

•  Uneven clamp pressures

•  Low sealing temperatures

•  Shrink film type

•  Incomplete sealing

•  Knife, wire, seal blade being used.

 

Solutions:

 

•  Adjust proper temperature to the sealing

•  Use even clamp pressures

•  Apply compatible shrinking films

 

5. Ballooning

 

It can happen when you expose heat shrink films to hot air where the inside air will expand, which makes it be able to gust out, and it will resemble a balloon.

 

Causes:

 

•  Perforated holes being poorly positioned

•  No perforations to evacuate air from the film

 

Solutions:

 

•  Use proper perforation

•  Don't allow more air at the film before you shrink

•  Use more holes

•  Properly position holes for the evacuation of air

 

6. Burn Out

 

They are due to more heat at the heat shrink film that causes tearing or burning as it shrinks. It can cause unwanted holes at the film since bubble package has improper heat.you can detect it in trials then correct before the package shrinks finally. Confirm everything is happening in the tunnel during shrinking.

 

Cause:

 

•  Fewer perforations

•  Slow tunnel conveyor

•  Package has voids

•  High temperature

 

Solutions:

 

•  Add perforation holes

•  Increase speed for tunnel conveyor

•  Reduce temperatures

•  Shrinking film gauge should be thicker.

 

7. Hazing

 

When there is a cloudy shrink film after the process, that is called hazing. Mostly it happens in voids when rounded bottles are being wrapped.

 

Cause:

 

•  More heat

 

Solutions:

 

•  Reduce temperature at the tunnel

•  Increase conveyor speed

 

8. Weak Seal

 

Here, the shrink bag sealing line is broken or can have holes.

 

Causes:

 

•  High sealing temperature

•  Sealing line improperly placed

•  Uneven sealing pressure applied

•  Dirty sealing blade/base surface

•  Damaged seal tape/pad

•  Fast sealing cycle

 

Solutions:

 

•  Reduce blade temperature

•  Place sealing line at the center of the product

•  Use even sealing blade and confirm the sealing pad is okay

•  Cleaning the sealing blade/base surface

•  Replace a damaged sealing tape/pad

•  Elongate the sealing cycle

 

9. Bad Seal Position

 

Here, the shrink bag sealing line is not placed at the product’s center.

 

Causes:

 

•  Improper sealing conveyor or table height

•  Improper sealing frame height

•  Wrong sealing frame blower direction

•  Large shrinking bag

 

Solutions:

 

•  Ensure you reset the sealing table height or its conveyor belt height

•  Ensure the sealing frame has a reset height

•  Make sure the shrink tunnel blower direction is placed correctly

•  Use a tighter shrink bag

 

10. Crushing

 

The crushing of the product happens when the shrink film crushes it since there is a large shrinking force.

 

Causes:

 

•  There might be a high shrink tunnel temperature

•  Very low shrink tunnel speed or conveyor speed

•  Very small shrink tunnel bag

•  Incompatible shrinking film for packing the products

 

Solutions:

 

•  Ensure the temperature of the shrink tunnel is decreased

•  Increase the conveyor speed of the shrink tunnel

•  Ensure the heat shrink film bag is big

•  Select the compatible shrink film

 

When having your products packaged with heat shrink film, you need to make sure such issues are not available in your packages and if they are found, then fix them using the provided solutions immediately so you can have an attractive package of good quality. People always like attractive products with no any issues in them.


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