Common Shrink Wrapping Machine Problems and How to Fix Them

Shrink Wrapping Machines are widely used across Australia’s food, beverage, pharmaceutical, logistics, and retail sectors because they keep products safe, stop people messing with them, and generally make them look a lot more presentable on store shelves. The global shrink packaging machinery market was valued at around USD 617 million back in 2017 and was expected to hit USD 1 billion by 2026. A pretty big increase considering just how much companies like minipack.com.au are relying on automated packaging systems these days. As production levels go up, even tiny problems with the machines can end up costing a lot of money through waste, lost time and having to reject products that have been messed up.

Those Wrinkly Packagings Inconsistent Shrinkage

The snag that pops up most often is uneven shrinkage, which causes little wrinkles, and the film either doesn’t stick properly or is all loose. The manufacturers of packaging gear have done some research and found that the main reason for this is that the heat isn’t being distributed evenly, or the tunnel temperature’s set wrong, or the conveyor speed isn’t right. All of which can lead to some pretty poor packaging. When the temperature’s set a bit too low, the film doesn’t shrink right around the product, and if it’s too high, well, it just gets all distorted and that’s not what you want. Production checks have turned up the fact that a tiny bit of temperature variation can really make a big difference in the quality of the shrinkage, especially when it’s POF films you’re working with.

Weak or Crappy Seals

Seal failures are one of the most expensive problems you can have because they leave the product not properly protected. Seals that aren’t up to scratch can cause the package to open up during transport, contamination risks are higher and then there’s the added bonus of higher rejection rates during quality checks. Studies on packaging line failures have shown that the most common causes are the wrong sealing temperature, not enough time to seal (dwell time), sealing wires that need replacing, or the sealing surfaces aren’t properly clean. All of which basically just means that your product isn’t as safe as it should be. In a lot of cases, operators just try to sort the problem by turning the temperature up a bit more but in reality, successful sealing is all about getting the right balance between heat, pressure, and how long the sealing process takes.

Tearing and Burn-Through Film

Tearing the film can quickly cause a lot of extra waste and slow the packaging line down big time. The problem normally occurs when it’s too hot in the tunnel or if the products have some sharp bits that put too much stress on the film when it’s shrinking. Maintenance reports have shown that overheating is one of the main causes of film damage. When the heat gets too high, it weakens the film, and if the film is poor quality or if the wrong gauge of film has been used, then you’ve got even more failures on your hands. One way to prevent some of the damage is to select a film that’s the right thickness for the weight of the product, reduce the tunnel temperature when you need to and get rid of any sharp edges on the product by using corner guards or modifying the design.

Air Traps & Ballooning

Ballooning is what you see when air gets trapped inside the package and swells it up, making the whole thing look a bit ugly and unstable. While it’s often just a cosmetic problem, trapped air can also cause issues with packing the boxes tightly together and getting them off the production line easily. Diagnostics on packaging show that often it’s because the film isn’t ventilating properly and the conveyor is running a bit too fast. When the package goes into the shrink tunnel before the air can get out, the pressure builds up and you start to see air pockets.

Fiddling Film Placement & Alignment

If the film is misaligned it can make for lousy centrefold seals, uneven shrinkage, and an awful lot of wasted material. In high-volume production, even a tiny bit of misalignment can add up pretty fast. Most of the time it’s because the rollers are worn out, or people have gotten the wrong tension on the film, or they haven’t adjusted the alignment guides correctly. Film tracking problems often sneak up on you. You don’t even notice them until they start causing problems. Regularly checking on the rollers, guides, and tension controls is the way to stop these problems before they cause too much damage in production. More and more facilities are now scheduling regular calibration so that their alignment stays spot on and they don’t waste as much film.

Shrink Tunnel Performance Woes

The shrink tunnel is the most energy-hungry bit of the whole shrink wrapping system so getting it right is really important if you want to pack the boxes up properly and save some money too. Problems with airflow, zapped heating elements, and poor temperature control all add up to trouble and a lot of the time it’s not even temperature that’s the issue. It’s getting the airflow sorted properly. Maintenance checks show that a lot of operators keep fiddling with the temperature settings without even thinking about the airflow. Airflow imbalance is the main culprit when you end up with loose film, wrinkles, and inconsistent shrink results. Keep the fans clean, check the heating elements and make sure the air is flowing the way it’s supposed to get the tunnel running smoothly. This is where maintenance programmes are so important.