Centerfold Film Sizing

The PRODUCT WIDTH (W) is run parallel to the CENTERFOLD (CF) edge of the film. Thus the product width would be run in the MACHINE DIRECTION (MD).

The PRODUCT LENGTH (L) or longest dimension of the package is run parallel to the CUTOFF (CO) or cross seal. This is the CROSS MACHINE DIRECTION (XMD).

When the package is positionned in the cross machine direction (xmd) as explained above, the length of the cutoff scrap is reduced, thus providing film savings. The following illustration demonstrates this method.

If the package is too long to run in the cross machine direction (XMD), then the package length must be run in the machine direction (MD).

The rule of thumb formula for determining the film WIDTH of centerfolded film required to package a product is:

MANUAL AND SEMI-AUTOMATIC “L” SEALERS

1. Centerfold Film Width

(Product Length) + (Product Height) + 2.0” (For 0” to 2.5” product height)
(Product Length) + (Product Height) + 2.5” (For 2.5” to 4.5” product height)
(Product Length) + (Product Height) + 3.0” (For > 4.5” product height)

2. Cut Off (Film Length)

(Product Width) + (Product Height) + 1.0” (For 0” to 2.5” product height)
(Product Width) + (Product Height) + 1.5” (For 2.5” to 4.5” product height)
(Product Width) + (Product Height) + 2.0” (For > 4.5” product height)

3. Film Usage

To calculate the amount of film used – multiply the Film Width (#1 above) by the Cut Off (#2 above) by 2. This will provide you with the total film usage per-package in square inches.

(CF Width X Cut Off) X 2 = Film Usage Per Package (sq. in)

Example (Manual & Semi L-Sealer)

Product Size: 17” L X 8” W X 2” H

CF WIDTH = 17 + 2 + 2 (L + H + Factor)
CF WIDTH = 21”

CUT OFF = 8 + 2 + 1 (W + H + Factor)
CUT OFF = 11”

 

AUTOMATIC “L” SEALERS

	1. Film and product advance through inverting head to discharge conveyor.
	2. Seal bars close and cycle. Next unit of product loaded on infeed conveyor.
	3. Bagged product discharges to shrink tunnel at the same time film and next unit of product advance to discharge conveyor as cycle repeats.

1. Centerfold Film Width

(Product Length) + (Product Height) + 4.0” (For 0” to 3.0” product height)
(Product Length) + (Product Height) + 4.5” (For 3.0” to 6.0” product height)

2. Cut Off (Film Length)

(Product Width) + (Product Height) + 1.0” (For 0” to 2.5” product height)
(Product Width) + (Product Height) + 1.5” (For 2.5” to 4.5” product height)
(Product Width) + (Product Height) + 2.0” (For > 4.5” product height)

3. Film Usage

To calculate the amount of film used – multiply the Film Width (#1 above) by the Cut Off (#2 above) by 2. This will provide you with the total film usage per-package in square inches.

(CF Width X Cut Off) X 2 = Film Usage Per Package (sq. in)

Example (Automatic L-Sealer)

Product Size: 17” L X 8” W X 2” H

CF WIDTH = 17 + 2 + 4 (L + H + Factor)
CF WIDTH = 23”

CUT OFF = 8 + 2 + 1 (W + H + Factor)
CUT OFF = 11”

Square Inches per Package

The number of square inches per package is required to determine film cost per package when the price per 1000 square inches is known.

Formula

CF Width X Cut Off Length X 2 = Square Inches Per Package

The “2” in the formula is required since when using CF film there are 2 layers of film being used for the package.

Example

Product Size: 17” L X 8” W X 2” H
- See examples above for CF Width and Cut Off Calculation

(Manual and Semi L-Sealer)
CF W 21” X CO 11” X 2 = 462 square inches

(Automatic L-Sealer)
CF W 23” X CO 11” X 2 = 506 square inches

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