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HOW TO CALCULATE WHAT THE WEIGHT OF A SPECIFIC SPEC PRODUCT SHOULD BE:

DIFFERENCES BETWEEN BLOWN AND CAST STRETCH FILMS

          EXAMPLE: 450mm X 20µm X 1000m roll is 0.45 X 0.02 X 1000 X 0.92 = 8.28kg plastic.
The weight of the core should then be added for the total roll weight.

BLOWN STRETCH FILM

CAST STRETCH FILM

FILM PROPERTIES BLOWN STRETCH FILMS
LOAD RETENTION Excellent holding properties in use.
Will not stretch much further after application.
FILM MEMORY Good material memory to return
to original size.
Has increased stretch and can wrap
FILM YIELD more pallets with the same length.
PUNCTURE RESISTANCE Manufacturing process creates greater
resistance to breakage of film.
CLING OF FILM 1 sided cling, useful for higher load retention
and prevents pallets sticking together in transit.
VISUAL CLARITY Not fully clear which can make barcode
scanning harder. However film has lower
gloss thus reducing reflections.
NOISE WHEN UNROLLED Can be very loud when releasing from the roll.
FILM PROPERTIES CAST STRETCH FILM
LOAD RETENTION Will stretch after application so
palletised loads can be less stable.
FILM MEMORY Less material memory than blown film.
FILM YIELD Not as much stretch as blown film.
PUNCTURE RESISTANCE Tearing can occur when film is highly stressed
CLING OF FILM Can have cling on both sides that can cause
pallets to stick together
VISUAL CLARITY Perfectly clear, makes reading and scanning in
warehouse light easy, but a higher gloss makes
reflections which can reduce barcode read rates.
NOISE WHEN UNROLLED Very quiet when unwound from the roll.

A PROFILE

Semi-Automatic machine criteria

    A pallet load with load footprint the same size as the pallet, with uniform shape and no protrusions.

B PROFILE

Semi-Automatic machine criteria

A pallet load with load footprint different to the size of the pallet with the load slightly irregular shaped.

 

C PROFILE

Semi-Automatic machine criteria

    A pallet load where the load footprint is significantly different to the size of the pallet and the load is highly irregular with many sharp edges or protrusions.

CRITERIA MANUAL WRAPPING
Throughput Limited by ability of labour
PROFILE A Suitable
PROFILE B Suitable
PROFILE C Suitable
Flexibility Highly Flexible
Consistency of application Wrapping patterndependant on operator
Film damage & Waste High
CRITERIA SEMI-AUTOMATIC
Throughput Cost effective in most throughputs greater than 100 pallets per day
PROFILE A Suitable
PROFILE B Suitable
PROFILE C Not Recommended
Flexibility Flexible
Consistency of application High
Film damage & Waste Low
CRITERIA FULLY AUTOMATED
Throughput Requires large throughput
PROFILE A Suitable
PROFILE B Suitable
PROFILE C Not Recommended
Flexibility Inflexible
Consistency of application High
Film damage & Waste Low

Referenced from Optimisation of pallet wrapping film use (https://www.slideshare.net/BobGiles/pallet-optimisation-64943165)

MULTI-LAYER CAST MATERIAL

The assumption that a high number of layers in multi layered films makes it stronger, is incorrect. The importance rests on what is put inside the layers rather than the number of layers. Coextruding layers with a single polymer increases the throughput of the production, but does not affect the properties.

Read more on multi-layer cast material: http://www.ptonline.com/articles/stretching-film’s-limits.