Handy Math > Metric Units > Yield Auditor  >  FORMING A PACKAGE by Cutting off One Sheet and Wrapping Around the Case with a Wand

FORMING A PACKAGE by Cutting off One Sheet and Wrapping Around the Case with a Wand

Complimentary Slide Rule ca. 1976

If you are shrink wrapping cases, you are a converter. You buy film by the kilogram and cut it off into sleeves before it goes into the shrink tunnel. If you buy 55.88 cm X 50.8 µm 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 kilogram 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:  55.88 cm wide                  50.8   µm (micrometer / micron) gauge                  86.36 cm cutoff             Half of the web width or  ½ of 55.88:                             27.94 cm X 86.36 cm X 50.8 µm X .0001849 = 22.66 kg / 1,000 packages                    Half of the web cutoff or  ½ of 86.36:                             43.18 cm X 55.88 cm X 50.8 µm X .0001849 = 22.66 kg / 1,000 packages

Example: Here is an example of film which is 6% "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:     55.88 cm 50.8 µm (micrometer / micron) (ostensibly) 40.64 cm od rolls 34.93 kg per roll No footage marked on roll tags one roll cutoff style   86.36 cm cutoff 1,443 packages from 1 roll of film Step 1: measured cutoff = 86.36 cm   Step 2: 1,443 packages from 34.93 kg of film Step 3: weight per 1,000 packages =                                                 22.66 kg / 1,000 Step 4: 34.93 kg ÷ 22.66 kg / 1,000 = 1541 "theoretical yield" from 34.93 kg film Step 5: compare actual (1,443) to theoretical (1,541) In this example, the real cost per 1,000,000 cases assuming a price of €1 per kilogram is €24,019 not €22,660.

Weight per 1,000 Cutoffs Calculator:      Width (cm):    Cutoff (cm): Gauge (µm):                  Weight:   kilograms per 1,000 packages                          Theoretical Yield Calculator Weight: kilograms per 1,000 packages Number of Kilograms per Roll (kg): Number of Rolls: Theoretical Yield:  packages