PE Films Weights and Measures
Yield Auditor - English Units
Single Roll Cutoff with Wand
and
Heat Seal Pass Through: Roll on Top / Roll on Bottom
Complimentary Slide Rule ca. 1976
Check Out the Yield Auditor for Heat Seal Pass Through: Roll on Top / Roll on Bottom
Single Roll Cutoff with Wand
If you are shrink wrapping cases, you are a converter. You buy film by the pound and cut it off into sleeves before it goes into the shrink tunnel.
If you buy 22 in. X 2 mils sheeting and have one ply on top & bottom, for practical purposes, you are making a bag. Multiply the weight per 1,000 packages by the price per pound to derive the cost per 1,000 cases.
If you cutoff one sheet at a time - simple. Just imagine a bag by folding either the width or length of the cutoff so there are two plys.
Example:
Half of the web width or ½ of 22": 11" X 34" X 2 mils÷15 = 49.86 # / 1,000 packages
Half of the web cutoff or ½ of 34": 17" X 22 X 2 mils÷15 = 49.86 # / 1,000 packages
Example:
Here is an example of film which is 7% "heavy" and well within the ± 10% industry tolerances. However, the film is produced "heavy" adding cost to the packages without the customer realizing the additional cost:
If you buy 22 in. X 2 mils sheeting and have one ply on top & bottom, for practical purposes, you are making a bag. Multiply the weight per 1,000 packages by the price per pound to derive the cost per 1,000 cases.
If you cutoff one sheet at a time - simple. Just imagine a bag by folding either the width or length of the cutoff so there are two plys.
Example:
- 22 in.
- 2 mils
- 34 in. cutoff
Half of the web width or ½ of 22": 11" X 34" X 2 mils÷15 = 49.86 # / 1,000 packages
Half of the web cutoff or ½ of 34": 17" X 22 X 2 mils÷15 = 49.86 # / 1,000 packages
Example:
Here is an example of film which is 7% "heavy" and well within the ± 10% industry tolerances. However, the film is produced "heavy" adding cost to the packages without the customer realizing the additional cost:
- 22"
- 2 mils (ostensibly)
- 16" od rolls
- 77 pounds per roll
- No footage marked on roll tags
- one roll cutoff style
- 34" cutoff
- 1,443 packages from 1 roll of film @ 77 pounds per roll
Step 1
measured cutoff = 34″
Step 2
1,443 packages from 77 pounds of film
Step 3
weight per 1,000 packages = 49.86 # / 1,000
Step 4
77 # ÷ 42.53 # /1,000 = 1,544 "theoretical yield" from 140 # film
Step 5:
compare actual (1,443) to theoretical (1,544)
In this example, the real cost per 1,000,000 cases assuming a price of $1 per pound is $53,350 not $49,860.
Heat Seal Pass Through: Roll on Top / Roll on Bottom
Example:Here is a nearly perfect scenario:
- 22″
- 2 mils 16″ od rolls
- 70 pounds per roll
- No footage marked on roll tags
- one roll on top one roll on bottom
- 2 rolls of shrink film in a heat-sealed pass through fashion
- 29″ cutoff
- 3,309 packages from 2 rolls of film @ 70 pounds per roll
Step 1
measured cutoff = 29″
Step 2
3,309 packages from 140 pounds of film ( 2 rolls X 70 # / Roll)
Step 3
weight per 1,000 packages = 42.53 # / 1,000
Step 4
140 # ÷ 42.53 # /1,000 = 3,292 "theoretical yield" from 140 # film
Step 5
compare actual (3,309) to theoretical (3,292)
In this example, the yield is practically perfect and there were 17 "free" packages from "light film".