Are the results of your shrink-wrapping endeavors consistently less-than-ideal? Your first instinct might be to blame your shrink wrap machine. But what if the problem is actually your product instead?
Machines are smart, but they aren’t know-it-alls or jacks-of-all-trades. If your machine isn’t built to accommodate your product’s material, shape, or size, things can quickly go awry. In this article, we’ll explain how your product causes poor results on your shrink-wrapping and how to achieve better, more consistent results.
Is It Your Machine? Or Your Product?
Is your machine causing the problem, or is it your product? A broken, old, or worn-down machine can lead to poor results on your shrink wrapping, but so can making your machine wrap products that it isn’t equipped to wrap.
So how do you tell who the troublemaker is? Parsing through your machine’s user manual and inspecting a few key areas of your machine will help you determine the source of your shrink-wrapping woes.
What To Look At
The Size of the Heat Tunnel
The first part of your machine you’ll want to inspect is the heat tunnel. How big is it? More importantly, how big is it relative to your products? If your products are too big for the tunnel, they might scrape against or snag on the heating elements as they pass through. This can perforate the film.
The Temperature of the Heat Tunnel
How hot is the heat tunnel? If it isn’t hot enough, your products won’t come out properly sealed. At the same time, a heat tunnel that’s too hot can also cause problems.
If the heat tunnel isn’t heating up enough, that’s a sign that your machine needs adjustment or repair. If your products come out of the heat tunnel melted or damaged, heat-test them to see exactly how much heat they can withstand.
So how does your product cause poor results on your shrink-wrapping? There are a few ways that your product can influence the results of the shrink-wrapping process.
Is your product oddly shaped, oversized, or undersized? Products that don’t fit the traditional mold move through shrink wrap machines differently and may not come out as you expect them to. To see if your machine can handle your product, take note of the item’s weight and dimensions, and compare them with the dimension requirements indicated in the machine’s user manual to see if your product will run through the machine smoothly. If your machine has rollers, you need to be extra cautious because a product that’s oddly shaped or of an inappropriate size can damage the rollers and chain.
If you can’t find this information in the manual or any other documentation, contact your machine’s manufacturer for more information.
There are many kinds of belts and belt add-ons that you should keep in mind. Some kinds of belts don’t mesh well with particular products or films.
Metal belts, for example, are incompatible with polyethylene films. The film sticks to the metal, which can result in tearing and other problems. If you use polyethylene film, stick to Teflon or fiberglass mesh belts for the best results.
If you’re wrapping heavy products or regularly have multiple items on the belt at a time, using a plastic grid belt is the best option to keep stalling to a minimum.
And if your product is constantly moving around on the belt, you might want to consider setting up some guides to keep it in the middle and steady.
What kind of film are you using to wrap your products? Your machine could be incompatible with the size or gauge you’re using. However, there’s also a chance your product is incompatible with the film you’re using.
The chemicals in some products, such as perfumes, react uniquely to films and can negatively affect shrink-wrapping results. Make sure the kind of film you’re using is compatible with your machine, belts, and product before you use it.
Common Shrink Wrap Problems and How To Fix Them
What kind of problem are you experiencing the most when you shrink wrap your products? Different problems have different causes and solutions. Here’s what you need to know about some of the most common shrink-wrapping problems and how to fix them.
Dog ears are triangular protrusions that appear around the corners of the packaging. This is an exceedingly common shrink-wrap problem that occurs when the corners of the film don’t shrink sufficiently.
This can happen for a variety of reasons. Insufficient heat, irregularly shaped or sized products, using a larger film width than necessary, and using low-quality films (especially PVC film) are all potential causes of dog ears.
Crow’s feet, which are wrinkles that extend from the corners of packaging, usually occur alongside dog ears. They show up due to an excess of film around the corners of the product.
There are two ways to reduce or eliminate crow’s feet. The first is to use a smaller shrink wrap or shrink tubing. The second way is to ensure the heat tunnel is producing enough heat to shrink the film uniformly.
Fish eyes are round or oval patterns that give the film an uneven and speckled appearance. Fish eyes are another problem resulting from a lack of heat, so if you’re experiencing them regularly, ensure your heating element is working properly.
Fish eyes are also common with low air velocity, so double-check that the tunnel air velocity is high enough. Another cause of fish eyes is perforations in the film, which you can keep to a minimum by turning down the conveyor speed.
Angel hairs are strands of melted plastic that stretch across the film. A few common causes of angel hairs include sealing wires or seal bars that aren’t hot enough, uneven clamp pressure, and a too-fast conveyor speed.
Ballooning occurs when you expose the wrap to hot air after sealing, which causes the air inside to expand. You can eliminate ballooning by switching to pre-perforated film, which has tiny vent holes that allow air to escape. Don’t worry—these holes aren’t noticeable after shrinking!
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