For years people have argued that powered pre-stretch stretch wrappers are a must. WHY?
- Our Legs are replaced by an electric motor
- So every time the motor turns sprocket A one time, sprocket B turns twice.
- NOW if each sprocket was attached to a roller that carried film, and they are the same size, for every rotation of sprocket A, B would turn twice which would create a stretch between the rollers of 100%.
- The force it requires to stretch the film is absorbed by the motor. Therefore with a POWERED PRE-STRETCH machine you can lay the film on loose like a dust cover, or so tight it either breaks the film or crushes the product being wrapped.
- The film is pulled through the rollers and attached to the pallet to be wrapped.
- So every time the motor turns sprocket A one time, sprocket B turns twice
- In the above sprocket example, you will still get 100% stretch but not the pallet will rotate pulling the film out f the machine.
- The force it requires to stretch the film is absorbed by the PALLET OF PRODUCT. Therefore with a NON-POWERED PRE-STRETCH machine you can only wrap pallets in film that have the stability to stay in-tact while forces are applied equal to what it takes to stretch the film.
- EXCEPTION TO THE RULE – Core brake technology does not use gears and sprockets to change the stretch, they incorporate a braking method on the roll carriage that will create resistance. Changes to the brake tension will create changes in stretch.
DOES THAT MAKE SENSE?
As you can imagine, if I have an 80 gauge film and a 45 gauge film, they will take different force to stretch them both the same amount. As wise man has taught me over the years “There is no replacement for mass”, so it is most likely the 80 gauge will require more force to stretch 200% than a 45 gauge. So what does that mean to you, the consumer? You will get less containment with a 45 gauge film than an 80 gauge because it takes less force to stretch it to its maximum point of elongation, or it will break with less force than the 80 gauge.
NOW LET’S TIE IT ALL TOGETHER:
Because of what we just discussed regarding film and the types of stretch machines available, what is right for your Non-Powered Pre-Stretch machine? Lets take the following items into consideration:
- What is the value of the load being wrapped?
- How far is it travelling?
- How is it being shipped?
- What is the weight of the pallet load being wrapped?
MY SOLUTION: Apply the 45 gauge so it stretches 125% (again, determined by the force you can apply without pulling your pallet load apart). All of the force is applied to the load giving you excellent containment force and as the film is thinned and applied it is probably in the area of the same thickness of the Powered Pre-Stretch applied film.
WHY DO THIS: It all boils down to ROI (return on investment), if you are wrapping under 30 pallets a day, this is a very viable, justifiable process with tremendous labor savings and typically a great return on film as compared to hand wrapping.
QUESTIONS ABOUT POWERED VERSUS NON POWERED PRE-STRETCH? Ask firstname.lastname@example.org!