Get Wrapped with Shrink Wrap

The Many Uses of Shrink Wrap

noreply@blogger.com (Veronica) — Mon, 05 May 2008 05:16:00 +0000

by: Steve Valentino

In the kitchen, shrink wrap keeps leftovers fresh and prevents spills in the microwave, but shrink wrap is also used in various industries to protect fragile items. Shrink wrap protects and groups pallets of items like glass and DVDs during shipment. Packaging shrink wrap is made from a plastic similar to the wrap used in kitchens, and it shrinks when it is heated. The heated shrink wrap makes a protected seal around the item. Shrink wrap systems vary in size, throughput rate, and level of automation, and films come in different thicknesses, stiffness, clarities and sizes.

Industrial businesses use shrink wrap to protect ship goods while they are being shipped. Several varieties of shrink wrap
packaging equipment are for sale. Smaller, often portable, systems start around $200, but larger, more elaborate systems
can cost anywhere from $2,000 to $35,000. Smaller equipment is often used by artists or art dealers to protect their works. The shrink-wrapped package makes the art look professional while protecting it from dust, dirt, and moisture. Acid-free or
archival-quality shrink wraps are available, though these are more expensive. Other smaller shrink-wrap systems package CDs, DVDs, and software for shipment. The larger shrink wrap systems are electronic and can package letters, boxes, books, industrial equipment and even traffic signals.

There are many different kinds of shrink wrap film, ranging in thickness from three-fourths of an inch to one inch. Prices
typically depend on the length, width, and qualities like shininess, clarity, flexibility, and the melt temperature of the
film. Prices start at around $50 but can reach several hundred dollars. Films are often made of Polyolefin or PVC. Polyolefin films have high clarity and are suited for automatic machines with a high throughput rate. PVC films are more resistant to tears and punctures. To shrink the shrink wrap, a hand-held heat gun is used to shrink wrap smaller items in small quantities. Heat tunnels with conveyor belts automate the process and can process large items quickly.

Shrink-wrap equipment and films are available online from a variety of retailers and wholesalers.

About the author:
Shrink Wrap Info provides detailed information about shrink wrap machines, systems, bags, as well as CD and DVD shrink wrap, and shrink wrap for boats. Shrink Wrap Info is affiliated with Original Content Web.

An Introduction to Shrink Wrap Machinery

noreply@blogger.com (Veronica) — Mon, 03 Jul 2006 02:14:00 +0000

by: Richard Jankel

The shrink wrap process involves two stages : the enveloping of the pack in shrink wrap either totally or partially and the application of heat to the shrink wrap film which activates the material's memory of its non-stretched molecular chains.
The application of shrink wrap can be divided into two principal types : transit and display.

Transit
The purpose of transit packaging is to offer the lowest cost option for packaging. The material used is almost exclusively polyethylene, which will provide the appropriate strength at the lowest available cost. A typical application is the collation of individual packs with or without tray support. The most frequent use of the forgoing involves the packaging of a quantity of cans or bottles or cartons for distribution.

The equipment used involves a sleeve or bundle sealer working in conjunction with a shrink tunnel. Two rolls of material produce a sleeve of film around the pack, which is then processed through the tunnel. Generally, these open sleeves do not cause any disadvantages to the pack integrity although a modification can be made to the tunnel whereby an attempt is made to have the hole closed through excess, annealed film.

A considerable amount of automation is offered for this process so that one may find a full range of manual, semi and fully automatic sealers and at maximum through-put, one can find lines with speeds of up to 200 packs per minute.

The processing of polyethylene is distinguished by the need for the shrink wrap film to reach an almost melt state, after which cooling will provide significant additional shrink. As a consequence, tunnels require specific cooling devices if elevated output speeds are needed.

All of this equipment may be used to wrap individual packs where collation is not required but a degree of protection is needed. Applications may vary from radiators through to office doors and bolts of cloth.

Display
The identical processes are also applied but with display shrink film where products have a natural requirement to use a sleeve. Gift wrap and wallpaper rolls fall into this category. The principles remain the same although both the sealer and tunnel will be modified to accommodate individual rolls with appropriately small diameters.

Turning to mainstream display applications, the main characteristic is the use of a total wrap.
In every single case, the sealer must now create a flat, two-dimensional bag around the product.
The product and this bag are then processed through a shrink tunnel to achieve the desired effect.

At the most basic level, this is achieved using an L-Sealer and folded film. The product is manually placed between the two layers of film and again manually placed into the sealer. The seal is completed and the pack placed on the tunnel conveyor. This is a continuous process that also produces an element of scrap film.

Automation is applied to the seal head and also to the pack support. Then, the seal process and the removal of the pack to the tunnel become automated. Generally, this is regarded as semi-automation. The clamping of the sealer head will be carried out using either a solenoid or a pneumatic ram.

Full automation of an L-sealer will allow packs to be automatically fed into the film and through to the sealer.

Manual vs. Automatic
Over the last few years, there has been a general polarisation of the above machines into manual and fully automatic, with relatively few machines being used in semi-automatic form. A manual machine will produce in the order of 10 packs per minute whilst a fully automatic will produce in the order of 20 packs per minute and there is relatively little speed advantage to be gained from a semi-automatic sealer.

Costs also have a significant influence here since entry level equipment can be purchased at significantly less than 2000 pounds whilst fully automatic shrink wrap machinery can be purchased at significantly less than 20,000 pounds.

The conventional use of a manual sealer and tunnel has been significantly reduced by the use of combined seal and shrink machines, commonly referred to as chamber equipment. These machines have a particularly small foot print and operate generally from single phase. The sealer head incorporates a plastic enclosure whilst heat is stored within the unit so that a combined seal and shrink can take place.

The maximum output that can be achieved from a fully automatic sealer will be in the order of 25-35 packs per minute.

As a consequence, both side seal and flow wrap machines are used to offer speeds approaching 100 packs per minute. The methodology remains the same as ever, to wrap the pack in a two dimensional bag of shrink wrap film.

Frequently, flat film is used although folded film is still applied by a number of machines. The sealer will be able to process individual packs at a much higher rate through the ability to seal at an appropriately higher rate.

Cross seals involve the seal device travelling with the pack whilst side seal or overlap seal mechanisms allow for film to be sealed continuously.

These same machines may be applied to other bagging requirements, in particular the mailing of magazines.

Machinery can be specifically customised to take advantage of any shrink wrap film's particular attributes to allow an appropriate pack to be achieved. One example of the foregoing is the modification of this process to allow for modified atmosphere packaging of food using barrier shrink film.

About The Author
This article was written by shrink wrap expert Richard Jankel with the support of Kempner, UK's largest distributor of display shrink wrap machinery and materials. For special offers please visit Kempner online at http://www.kempner.co.uk/

Source:
www.articlecity.com

To Shrink or To Stretch

noreply@blogger.com (Veronica) — Tue, 27 Jun 2006 04:24:00 +0000

Find out the differences between shrink and stretch wrap.
By Mel Parnes President. Ciratec Corp.

Shrink wrap is a packaging technique where the plastic film is wrapped around a product and heat sealed to form a loose envelope. It is then heated all over, causing the wrap to shrink tightly around the product. On the other hand, stretch wrap is an elastic film that is mechanically stretch around the product like a wide rubber band. It is not heat sealed but relies on a self adherence. It is applied in plys, overlapped it self.

Differences?

To visualise the difference, a toy or a box of software might be shrink packaged. You can see the line of the heat seal that was made before the shrinking took place, but the print on the product is clearly visible through the film. The film is clear and relatively slippery.

On the other hand, a pallet or skid of boxes is stretch wrapped. A stack of shrink wrapped boxes or software might be stretch wrapped. The film used is a hot like, if not identical to, the household wrap which we use to call "saran wrap" (it is usually not saran anymore). It is clear but many wrinkkes occur where the film overlaps it self, making it less aesthetically appearing.
stretch wrap is therefore more of a shipping tool, while shrink wrap is more to keep a product clean until after it is in the hand of the customer.

Functions

There are a lot of overlap in the functions of the two products. Shrink wrap is also used to package cases of dog-food and other products shipped in bulk where the package is opened at the market and it is not seen by the customer. Stretch wrap, on the other hand used more and more to unitise small bundles for shipping. Shrink wrap, is an older technique preceding stretch wrap by more than 10 years. Before stretch wrap was used, shrink wrap performed many of its functions. It was soon discovered that stretch wrap was better than shrink wrap for heavy duty industrial packaging, since it was no less effective and cheaper and easier to use.

Shrink wrap is energy intensive since heat must be produced to shrink the film. The shrink machinery usually requires more maintenance since heat sealing of the film is necessary. Stretch wrap film is designed to adhere it self (no adhesive is used though). The film has a high coefficient of friction. It can prevent a package from sliding when a stack of product is handled.
The prevention of sliding may not be an asset when the high triction creates handling difficulties for people, or sliding difficulties for certain types of machine handling.

Source:
www.apfoodonline.com

Shrink Wrap

noreply@blogger.com (Veronica) — Wed, 21 Jun 2006 05:36:00 +0000

Two major classification of shrink wrap:

For "point-of-sale" where the wrap has to sell the product-usually by not being in the way visually-rather expensive, special, oriented films are used. These films are very clear. When they shrink, they do so with alacrity, exerting energy on the product and shrinking with few or no wrinkles or distortion. This is high technology packaging where the film can be pre-printed with appropriate distortion so that the printing comes out perfect after it shrink.

Industrial shrink packaging, on the other hand, is done with more ordinary films which are less costly and shrinks when heated. In attempting to regain the form it was in or on its way out of the extruder.