This is a follow up post focusing on some common shrink wrap problems when sealing, and heat shrinking. As mentioned in the first post, we will be focusing on ballooning, hot spots, and splitting seals.
All three of these issues are fairly common issues when dealing with shrink wrap. Let’s start with ballooning.
Shrink wrap ballooning happens when the shrink film is exposed to hot air. The air inside of the bag expands and causes the shrink film to puff out causing a pillow effect. There are a couple of fairly simple solutions if you are having ballooning problems.
1. Try using a shrink film with vent holes.
2. If using a hand sealer in a low output operation, try to be sure there is not excessive air in the shrink film before beginning to seal.
3. If using shrink film with vent holes, make sure the vent holes are positioned properly for air to escape the most efficient way.
Ballooning is an issue that should be addressed by using a shrink film with vent holes. This is the best option to prevent ballooning and allow air to escape the shrink wrap.
Hot spots are areas in shrink film that become too hot and may cause unwanted holes in the shrink wrap film. These spots should be detected on trial runs and can be adjusted for. Below are some recommended adjustments to make if you are experiencing hot spots in your shrink film.
1. Adjust temperature of heat output. Whether using a heat gun, or a shrink tunnel try to adjust the heat settings.
2. If using a shrink tunnel try speeding up tunnel conveyor belt. This allows the shrink wrapped package to pass by the shrink tunnel quicker and reduce the length of time the heat is applied to the package.
3. If temperature is correct try adjusting the air velocity. If using a heat gun, try to hold the end of the heat gun further away from the shrink film during shrinking.
Air velocity and heat are going to be the two most common adjustments to look for when experiencing shrink film hot spots. If proper adjustments are made, you should not have issues with hot spots during production.
Splitting seals are a common problem that can cause a variety of issues with shrink wrapped products. A split shrink wrap seal can result in damaged products, non-detection of tampered packages, product loss during shipment, etc. There are several issues that can cause splitting seals and they should be addressed promptly to avoid some of the issues listed above. Try some of the troubleshooting ideas below to avoid splitting seals.
1. Try to up-gauge and use a thicker shrink film.
2. Check the quality of your shrink film.
3. Clean sealing wire.
4. Check clamp pressure on sealer.
5. Make sure the sealing cycle is completed before sealing jaws are released.
6. Try increasing wire temperature.
7. Try decreasing wire temperature.
Of the problems listed in this post, splitting seals can be the most costly for your products. Be sure to attempt all troubleshooting options to address the issue.