There are a variety of issues that can occur when using shrink wrap film. Some names the shrink wrap industry has chosen for common issues are interesting to say the least. We are going to go over a few issues that are common with shrink wrap film, what they mean, and what may cause them. Keep in mind that some issues are pretty common and you should not panic if you are experiencing them. The best thing to do is go through the checklist and see if you can address the problem.
Dog ears are a common issue and something we often see when buying a shrink wrapped product in the store. Shrink wrap Dog Ears are triangular protrusions of the shrink film at the corners of the product. There are several causes of dog ears and most shrink wrapped packaging has some form of dog ears.
The triangular protrusions of dog ears indicate insufficient shrinkage of the shrink film. There are a variety of issues that can lead to the corners not being shrunk.
1. The easiest issue to address is checking the heat of you shrink gun or tunnel to be sure it is putting out the proper amount of heat for proper shrinkage.
2. To large of shrink film, bag, or tubing. Using the wrong size of shrink film can result in dog ears. Try to downsize the shrink wrap you are using.
3. Poor Quality shrink film. It is often more common to see dog ears in PVC shrink wrap than Polyolefin shrink wrap. Polyolefin shrink wrap is considered a better quality shrink wrap, but comes at a higher price.
4. Non-uniform corner shapes and sizes. Sometimes the corner shapes of the packaging you are sealing will play a role in the possibility of dog ears.
There are dog ears in many retail shrink wrapped packages found in stores all over. If you have minor dog ears in the corners of your shrink wrapped packages it is not the end of the world. Be sure the dog ears are not to large and make the package look bad.
Often accompanied with dog ear’s, crow’s feet are wrinkles extending from the corners of shrink wrapped packages. When troubleshooting for dog ears there is often the possibility you can find the source of crow’s feet as well. The two most common causes of crow’s feet are listed below.
2. Insufficient heat has been applied to the package. Check your heat source to be sure the proper amount of heat is being applied.
Fish eyes are round or oval patterns on a package that has been poorly shrunk. Fish eye’s are an issue that needs to be addressed because of the ability to make you shrink packaging look very poor. The two main causes of fish eyes are listed below.
1. Inadequate heat. Check your heat source to be sure it is applying the proper amount of heat.
2. Improper air velocity. Make sure your heat source is pushing enough air velocity when applying heat.
Angel hair are thin strands of shrink film between the product being sealed and the sealed end of the the shrink wrap film. Because of the size of the angel hair, it is often not a major issue in most packaging situations. Below are some common causes.
1. Sealing Wire temperature is to low. Try to turn up sealing temperature. Try clean sealing wire or replace sealing wire.
2. Make sure clamp pressure on sealer is even.
3. Sealing cycle has not completed before sealer is opened.
We are going to write a second part about common shrink wrap issues people have. That post will focus on ballooning, hot spots, and splitting seals.