HOW TO CALCULATE WHAT THE WEIGHT OF A SPECIFIC SPEC PRODUCT SHOULD BE:
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
A pallet load with load footprint the same size as the pallet, with uniform shape and no protrusions.
B PROFILE
A pallet load with load footprint different to the size of the pallet with the load slightly irregular shaped.
C PROFILE
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.