SEGMENT 1:  DEFINITIONS OF COMMON SHRINK WRAP PACKAGING TERMS

1.       Shrink Wrap:   A method of packaging in which a thermoplastic film is wrapped and sealed around a product, encapsulating the product in a “bag” of film.  The process is completed by passing the wrapped product through a heated chamber, causing the film to shrink and conform to the shape of the wrapped product.  Shrink can be used for display and/or protective packaging.

2.       Centerfold:  The type of film used on “L” – Sealers.  The shrink film is a web which has been folded in half as it is wound onto the core, allowing for a an upper and lower web of film between which the product is placed for sealing on an “L” – Sealer machine.

3.       Compensator:  Controls the heat to the wire-temperature range.  The key control on an “L” – Sealer it is spring-mounted screw adjustment located on the extreme left end of the front seal bar which controls the heat of the seal wires by controlling the flow of electricity to these wires.  When the seal cycle is initiated, electricity flows into the wires and they heat up and expand as the springs keep the wires taut.  As the compensator contacts the screw due to the expansion of the heated wire, the electrical flow is terminated and wire begins to cool and contract.

4.       Conveyor Timer:  A control on semi-automatic “L” – Sealers which is used to control the time the take-away conveyor after the seal cycle is completed to move the wrapped products to the shrink tunnel.

5.       Cycle:  A complete repetition of all actions required to wrap a product in shrink film.

6.       Dead Roller:  A term used to designate that the individual rollers on a shrink tunnel’s roller conveyor do not rotate as the conveyor passes through the tunnel chamber.  

7.       Dwell:  The time during which the seal head of an “L” – Sealer remains down after the completion of the seal cycle allowing the seal to cool and “set up” enhancing seal strength.

8.       Dwell Timer:  A device which can be set to control the dwell time on a manual or semi-automatic “L” – Sealer.

9.       Heater Bank:  A resistance heating device which generates heat which is then directed through the chamber of a shrink film tunnel, causing polyolefin or PVC film to shrink around wrapped products.

10.   Skip Cycle:  An option which allows a form/fill/seal machine to double its length capacity by cycling the seal head only on every other horizontal stroke.

11.   Static Seal:  The standard longitudinal seal on Weldotron Segment 3 wrappers, its uses a static charge to bond the two edges of the film web together in an overlap seal.  It is the preferred type of seal for retail display packages, producing the best aesthetics and providing a strong seal with good overall package integrity.

12.   Thermal Seal:  An optional seal which uses a heated element of “drag wire” to form a “welded” bead seal in two layers of film as they pass over the heated element.  It is generally used to seal polyethylene, which does not statically seal effectively, but can be used to seal other films when a more positive seal is required than can be provided by a static seal.  Multi-count packages of heavier products (cans, bottles) generally are better-done with thermal seals due to their weight and the flexing they are subjected to in distribution.

SEGMENT 2:  DEFINITIONS OF COMMON SHRINK FILM PACKAGING TERMS

1.       Centering rollers:  Adjustable rollers used to center the centerfold shrink film onto the midpoint of the inverting plow on Segment 2 Weldotron machines to better control the flow of shrink film onto the plow and improve shrink film ”tracking”.

2.       Closing (or bridging) Conveyor: The outfeed conveyor has the capability to move toward the infeed conveyor during product feeding to close of bridge the gap between the two conveyors, enhancing the machine’s ability to handle short of stacked, loose products.

3.       Live/Dead Rollers:  This allows the conveyor to be run in either the live or dead roller mode to best accommodate the shrink characteristics of the film being used.

4.       Inverting Plow:  The adjustable device which opens and inverts the web of CF film, allowing products to be fed into the film for sealing.

5.       Photocells:  The “electric eyes” which detect the location of the products, controlling machine operation.

6.       Programmable Logic Controller (PLC):  The electronic “computer” which is the central control unit in automatic machines.

7.       Relay Logic:  The type of control system (non-PLC) used some models.

8.       Scrap Drive:  The system which controls the scrap tail and advances shrink film through the machine.

9.       Scrap Winder:  The mechanically-driven wheel which collects the scrap tail as it advances through the machine and is released from the scrap drive.

10.   Seal Bar:  A heated “knife” which cuts and seals film.  Unlike impulse wires, a seal bar operates at a constant temperature, enhancing seal quality and integrity while making the machine adaptable to more films.  The improved operating consistency of a bar also reduces maintenance and build-up of film residue.

11.   Vertically Rising Seal Head:  The FastPak’s seal head assembly moves in a vertical direction as a unit, unlike the hinged of most other machines.  This vertical orientation provides for more consistent seal pressure, assuring stronger, more consistent seals with less maintenance and machine wear.  In addition, the vertical orientation allows for better feeding of higher-profile products.

SEGMENT 3:  DEFINITIONS OF COMMON PACKAGING TERMS

1.       Adjustable Plow:  An adjustable film-forming device made of movable components which allow for multiple sizes of products and film to be used as the components are moved in relation to each other.  Adjustable plows are commonly used on edge-seal machines in one configuration and occasionally used on bottom lap seal machines in another configuration (fixed/adjustable).

2.       Cross-Seal Bridge:  An optional feature which minimizes the gap over which products must move at the cross seal, enhancing a machine’s ability to run shorter length products.

3.       Dual Zone:  A term used to describe a shrink tunnel with two individually-controlled zones within the chamber, with each zone capable of having separate operating settings from the other zone.  A dual zone tunnel allows for the greatest ability to run a wide range of films and to set up specific heat and air flow patterns within the tunnel for best shrink characteristics.

4.       Forming Plow:  The device on a Form/Fill/Seal machine which forms the film web in to the shape required to encapsulate the product being wrapped.  A fixed (or fixed/adjustable) plow generally forms a rectangular tube and is used on a bottom lap seal machine, while an adjustable plow usually forms a “C” – shaped open web on an edge-seal machine.

5.       Gated Indexer:  An optional infeed device which allows for “choke-fed” products to be separated and introduced to the infeed of an Fold / Fill / Seal machine properly spaced.  It incorporates a photocell to control the movement of “gates” which move up and down to stop and then release products properly indexed for introduction to the flights of an infeed.

6.       Planetary Seal:  The type of device used on Weldotron edge-seal machines, it incorporates two opposed heated wheels to cut and seal film.  One wheel has a cutting edge and the other acts as an “anvil” for it to cut against.  As their vertical relationship is changed, the type of seal created can be changed as required by the application.

7.       Print Registration:  An option which allows machines to run registered printed shrink films, it incorporates a photocell to “see” registration marks on the film and thus control film feed and cutoff relationships.

8.       Rectangular Orbit:  The term used to describe the movement of the Weldotron 1600-Series seal head in operation, which resembles a rectangle and allows for the most dwell for optimum film sealing capabilities.

9.       Singlewound:  The type of film commonly used on F/F/S machines, it is a single layer of film wound onto a core and formed on a plow.  Less expensive than centerfold it adds to the overall cost-efficiency of F/F/S machinery.

10.   Impulse Wire:  The type seal wire used on some sealers.  Impulse wires get hot during the seal cycle and cut and seal film.  Controlled by the compensator, electricity flows into the wires, causing them to heat up to the correct temperature for sealing the film in use.  When the compensator stops the flow of current, the wires cool and contract between seal cycles.

11.   Live Roller:  A term used to designate that the individual rollers of a shrink tunnel’s roller conveyor rotate as the conveyor passes through the tunnel chamber.  Properly used to shrink polyolefin and PVC films.

12.   Biaxally Oriented Shrink Film:  Film which during manufacture has been stretched equally in both directions and then cooled.  When reheated in a shrink tunnel it will shrink equally in both directions.

13.   Preferentially Oriented Shrink Film:  Film which during manufacture has been stretched more in on e direction than the other. When reheated in a shrink tunnel it will shrink more in one direction than the other.

14.   Polyethylene:  A commonly-used shrinkable film generally used for protective packages where aesthetic are of little concern, it is the least expensive film available but has less clarity and more shrink force than the “retail display” films.  Usually “preferentially oriented”.

15.   Polyolefin:  A “controlled force” shrink film with excellent clarity and consistency, commonly used for display packages.  It is the predominant all-purpose shrink film currently in use.  Usually “Biaxally oriented”.

16.   Polyvinyl Chloride (PVC):  A “controlled force” shrink film similar to polyolefin, but generally used as a lower-force film suited to products with unusual shapes and/or a tendency to curl as the film shrinks around them.  Can be either “preferentially or Biaxally oriented”.

17.   Seal:  The use of heat to bond two layers of film.  All machines seal film by controlling the time during which is introduced to the seal area, the temperature of the sealing device (impulse wires in Segment 1) and the pressure of the seal head holding the film immobile during the seal cycle. (T/T/P – Time/Temperature/Pressure)

18.   Speed:  Generally measured in cycles per minute.  Speed is a designation of a machine’s productive capacity, the operators motivation and the ability of the operator to handle the product.

19.   Tap Switch:  The control which varies the voltage of the current introduced to the impulse seal wires.  As voltage is increased, the wires heat up more quickly.

20.   Thermostat:  The control used to set the operating temperature of a shrink film tunnel.

21.   Velocity:  The speed or force at which the heated air is directed to the wrapped products as they pass through the chamber of a shrink tunnel on the conveyor.