Every year, suppliers of silage stretch film receive complaints relating to problems that are not a result of poor quality of inferior manufacturing, but of film mis-use or problems related to the wrapping machines. While we at the Crop Packaging Association try our best to advise on how to rectify common problems with crop packaging, sometimes it is very difficult to offer advice on a solution and it is better to explain exactly what causes the problem in the hope that the operator can find the best solution for his own situation.
Film breaking at the start of a wrapping cycle is a very common problem, one where the film’s quality is often called into question. In reality, there is no reason for the quality of film to differ at any point throughout its length and no way that any imperfection could always show itself at the same point in the wrap cycle every time. However, to understand exactly what is causing the ‘failure’ of the film at this point would offer the best option to find a solution.
Most film wrappers have a similar method of capturing the film at the end of the wrapping cycle, gather the film together and pull it onto the knife blade to cut the film. In gathering the film, a hydraulic clamp is often employed, which pulls the gathered film against a metal surface, at great speed. The film inside the clamp is held securely; however the film immediately outside the clamp becomes damaged as it is gathered, through being scuffed across the metal surface, a situation further exaggerated by the associated build up of tackifier from the film itself on the metal surface, which provides a very abrasive surface that easily damages the film. This scuffing leaves minute abrasions on the film’s surface which, when pulled at the start of the next wrap cycle, at a great acceleration speed, begin to weaken the film and pull into holes that eventually break the film.
Naturally, it is easy to assume that the film is not strong enough for the wrapper, but next time you suffer this problem, and you will at some time, please take time to look a little closer at the evidence that is right there in your hands, as you re-attach the broken film tail back to the bale. It is obviously much easier to see this happen when you are stood next to the wrapper’s catch and cut mechanism, but as this is not often possible, allow this be the proof you need to understand what’s happening.