Angel Hair -
the hot wire on a shrink wrap system is cutting and sealing, extremely thin
strands of shrink wrap film appears between the cut end of the shrink film and
the product being wrapped.
When shrink film is exposed to hot air a pillowing effect is created.
When heated trapped air expands and then slowly escapes through the vent hole(s) resulting in an even shrink.
The slender round weld produced by applying
time and pressure with a hot knife or wire to two layers of plastic shrink film.
the shrink wrap film as a tendency to stick to an adjacent shrink film
Burn Through Temperature - The
temperature in a shrink wrap tunnel at which shrink film becomes cloudy and
Centerfold Shrink Wrap Film -
With center folded shrink film the product
is inserted between the folded film and then the remaining three edges are
heat sealed. Primarily used on slower, semiautomatic and manual shrink
packaging equipment. Centerfold shrink wrap film has been folded in half lengthwise and
wound onto a dispensing core.
- The amount of force required to slide two cold surfaces of shrink film against
Cold-Temperature Flex -
the ability of shrink film to perform at low temperatures without fracture or failure.
A paper tube on which shrinkwrap film is wound. cores are furnished in 3" and
6" inside diameters; 3" is standard.
Crow’s Feet -
Occurs when a shrink wrapped package has received
insufficient heat shrink. Crow's feet are those series of wrinkles
emitting out from the corners of an overwrapped package.
Dog Ears -
Triangular protrusions of shrink film at corners of the trim seal. Usually
associated with insufficient shrink, high-profile packages, or both.
Drape - The
softness of a shrink film that is characterized by its conformance to product
contours and irregularities.
Edge seal -
Edge seal packaging is the formation of a secure or tight closure by the
junction of two layers of shrink film around the perimeter of a product or container.
Electronic Beam - Cross
linking - A process which binds the polymer chains into a network which
significantly increases the strength of the shrink wrapping film.
Electrostatic Seal -
The sealing process applying a static charge to two overlapping edges of
This is common on high speed horizontal shrink wrappers.
Fish Eyes -
A scalloped surface on a shrink film package. The defect has the general
appearance of rounded or oval areas that have not been completely shrunk.
A term which is associated with high-speed overwrapping equipment with
single-wound film. A designed forming shoe wraps the film around the product.
The film edges are secured with static or thermal lap seal on the bottom of
the package. A vertical or horizontal trim seal is then applied on the front
and back of the package.
The term used to describe the thickness of film. One mil is equivalent to 1/1
000 of an inch. Fifty gauge film is 1/2 mil thick, 100-gauge is 1 mil thick.
Hole Punch -
A pneumatically or electrically operated device composed of a punch
and die which produces a deflate hole in a film.
Hot Slip -
The amount of force required to slide two heated surfaces of film
Impulse Seal -
A heat sealing technique defined as electrically pulsing a resistance
wire for a specified length of time to effect a bead seal.
In-Line Center Folding -
An extrusion line used to produce centerfolded film which slits the
tubular film before it is wound onto cores.
A term which describes any of the automatic, semi-automatic, or manual
trim-sealing equipment in which the seal bars are arranged in an "L"
Lap Seal -
A seal made with two pieces of overlapped film with a heated wire, bar, or
with a static charge.
Longitudinal Direction -
Perpendicular to film width.
Low Temperature Flexibility -
The lowest temperature at which the shrink packaging film will withstand a specified
bending without fracture.
The ability of a film to form, fill, and seal on overwrapping equipment.
Machine Direction -
The direction in which the shrinkwrap
and shrink tunnel.
Mechanical Centerfold -The process by which single-wound or flat film is mechanically folded for use
on L- bar sealers.
After shrinking, the film retains the same characteristics. In other words,
the film has good memory.
Mil Thickness -
One mil is equivalent to 1/1000 of an inch.
1000 square inches.
Opaque - -
Relatively impervious to light.
Optics - -
The visual properties of a material, i.e., clarity, gloss, haze.
Orientation or Racking - -
The stretching technique used to obtain molecular alignment in film
as it is manufactured, which increases tensile strength and stiffness
and decreases tear strength of shrink films.
Oriented - The stretching and aligning of a material’s molecules at
temperatures below its melting points.
Overwrap Machine -
A machine which completely surrounds a product with film.
Perforator - Shrink packaging equipment feature that
automatically pierces microscopic vents in shrink film as the film is
Racking - -
A machine and a process for orienting plastic materials. A racking machine
orients material by continuously stretching the thick-walled, tubular tape in
both directions, to form oriented, shrinkable film.
Sealing Wire -
The wire that is heated by virtue of its resistance to
electrical current for the purpose of melting or fusing two layers of a
shrinkwrap film together. Seal wires range in diameter from .018 to .30
inches and are generally made of nickel chrome alloy.
Shrink Appearance - The appearance of
an over-wrapped package after shrinking at a specified temperature and
Shrink Temperature Range -
The temperature range in which a shrinkwrap film will effectively shrink and
produce a tight-fitting, aesthetically pleasing package.
Shrink Tunnel -
Heated chamber through which products are conveyed in order to shrink an
Singlewound Film- -
A term used to describe one layer of film wound around a core. It is
generally used on automatic shrink packaging equipment.
Skin Packaging - The
formation of contour fitting covers normally adhered to stiff paper board.
That quality of shrink film that permits it to move easily over metal or
against another piece of film.
An electrical charge built up in shrink packaging films that tends to make them adhere
to oppositely charge machinery or products. Can also be defined as cling.
Static Lap-Seal -
A type of longitudinal seal, applied using automatic shrink wrap equipment,
in which the edges of single-wound film are overlapped and adhered to one
another using an electrostatic charge.
A property of a shrink film that is characterized by its adherence to metals
another sheet of similar film.
Tap Switch -
A device used to control the amount of voltage supplied to the seal
wire of an edge or trim seal machine. The device switches the output leads of
a multi-output transformer. The tap switch is also know as a heat controller.
Tear Initiation -
The force necessary to initiate a tear in shrink films.
Tear Resistance -
The ability of the shrink wrap film to resist zippering or propagation of a tear.
Thermal Lap-Seal -
A type longitudinal seal, applied using automatic form/fill/ seal
equipment, in which the edges of single-wound equipment are overlapped and
adhered using a heated wire, block, or other mechanism
Shrink film that allows the passage of light, but diffusing the light so that any
product wrapped in the film it is not readily distinguished.
Transverse Direction - Is parallel
to the film width.
The edges of excess shrink film which are cut from a package.
Trim Seal -
A seal applied using a seal wire which melts and fuses layers of
together. The seal wire both seals and cuts excess material
from the package.
Vent Hole - A hole made in the
which allows the air between the product and the film escape as the film is shrinking.
The direction that shrink film is wound on a core. Shrink film can unwind
either from the top or bottom of the roll when viewed horizontally from
the open side.