Common Shrink Wrap Problems and How to Avoid Them
Shrink wrap (or shrink film) is a type of packaging material that is used to wrap products in a thin, polymer plastic film. Once heated, the wrap shrinks tightly around the product, which conforms to the item’s shape and creates a tight seal.
Shrink wrap has many advantages: protection, tamper resistance, and it ensures your product remains in pristine condition. It is used to package and protect items such as DVDs, electronics, and edible produce; such as fruit and vegetables.
However, using this material can come with issues. Most issues arise when the heat is improperly applied to a product, or when the wrap is not measured properly before application. This can cause dogs ears, burn holes, ballooning or even angel hair! Although these are preventable, and sometimes simple to fix, it is important to be aware of the problems when using shrink wrap.
Dog Ears
This may be exactly how you imagine it. “Dog ears” refers to the corners or edges of the shrink wrap, which can fold or wrinkle if not applied properly during the shrinking process.
It occurs when the material isn’t distributed evenly, or if excess heat is applied to specific areas of the item, causing the film to gather and fold.
This can create the appearance of the ears of a dog, and it is a very common issue of the material.
While some manufacturers do not find this a significant issue, failure to wrap the material to all edges and corners can lead to the risk of tearing in transit, if caught.
In order to prevent “dog ears”, we recommend the following:
- Assess the heating properties: check your shrink tunnel. It must be able to cover the package properly, whilst also being cool enough to avoid your item being damaged.
- Check the size of shrink wrap: when you are using this material to wrap an item, ensure that you have the correct measurements before you begin, so that you can avoid the leftover wrap that creates “dog ears”.
Burn Holes
Burn holes on shrink wrap can occur when the wrap material has been melted, or even burned, during the heat-sealing process.
This occurs when an excessive amount of heat is applied to the product, and not evenly distributed. Burn holes are a big concern because holes in your wrap increase the risk of damage before it reaches the end user. Without proper wrapping, the item does not have adequate protection, and its condition may be compromised.
In order to resolve such issues, it’s important to:
- Reduce your heat settings: avoid applying excessive heat that could cause the shrink film to melt.
- Use vent hole film: this allows the air to escape after the wrap has been applied.
Ballooning
Ballooning occurs when there is exposure to excessive air after sealing. This problem is common with items that have not been sealed before using shrink wrap. If the material is sealed before the film begins to shrink, the trapped air has nowhere to escape.
Ballooning in the packaging of a product can cause an uneven appearance, with the added risk of the product being tampered with in or around transit.
To prevent ballooning, we recommend the following:
- Proper ventilation: applying proper ventilation holes allows trapped air to escape as the film shrinks.
- Reduce conveyor speed: the hot air will have more time to escape from the shrink wrap once you slow down the process of application.
Wrinkling
Also known as “crows feet”, wrinkling appears around the corners of your product - forming a wrinkled appearance.
This is caused by an excessive amount of film on the corners of the product, which then form small pockets of exposed air.
Having “wrinkles” on your wrapped product results in an unprofessional display.In order to reduce “wrinkles”, you can:
- Reduce shrink wrap amount: use a smaller roll of shrink wrap to avoid pockets of air when wrapping the product.
- Increase temperature: wrinkling commonly occurs when the shrink tunnel machine is at too low a temperature.. Increasing the temperature will reduce the amount of wrinkling, helping you wrap the product more effectively.
- Decrease the Conveyor Speed: allow time for the air found in wrinkling to disappear before wrapping.
Weak and Improper Sealing
Having weak sealing on your product is a very common problem when using shrink wrap, caused simply because your film is not thick enough.
This can be more harmful to your item, so it requires immediate attention. If you find a split or weak sealing, it can seriously damage your product. Even a small split results in weak protection, tampering issues, and potential product loss.
Ways to avoid this issue include:
- Apply a thicker film: you may have a weak, or potentially tampered roll of film. Ensure your wrap is thick and strong enough to conform around your product.
- Clean your sealing wire: you want to be confident that your products are being wrapped with the maximum protection, so take time to clean your sealing wire, and make sure the machine is set at the correct temperature.
Angel Hair
These are thin strands of melted plastic that are formed during the heat-shrinking process. It occurs when the seal bar is not hot enough.
As the material melts, it stretches, resulting in thin, delicate strands, similar to hair.
Poorly wrapped products which show the appearance of angel hair create an unappealing appearance and potentially interfere with the product. For example, if you were to wrap edible produce, such as apples, the angel hair may interact with the apple - which could possibly result in contamination.
Prevent angel hair in shrink wrap by:
- Increase the temperature: apply more heat to the seal bar to ensure the hairs don’t form.
- Adjust the seal bar: ensure your seal bar is adjusted to be level when wrapping.
- Check clamp pressure: if you find that your clamp is uneven, it may not wrap well, resulting in angel hairs. Check your sealing wire works accordingly.
Find the Shrink Wrap Perfect for Any Item
At Polyflex, we are a leading supplier of polythene packaging products. Our team offers professional expertise with over 50 years in the industry.
Everything we supply is manufactured to our clients specific requirements from roll size, film thickness, custom printed film or covers, and more.
To request a quote or free sample, contact us today.
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