Laser perforations open new possibilities

08 Apr 2011

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Micron sized laser produced holes are an essential part of many manufacturing processes. Often difficult to see with the naked eye, these tiny apertures are used in packaging to control and extend the shelf life of many fresh products. Hole size, shape and position are controlled to micron dimensions, providing the specific functionality required.

Modified atmosphere packaging (MAP) is an excellent example of how the flexibility of the laser perforation process can be used to good effect. This type of packaging is used to increase the shelf life of fresh and refrigerated food products. The growth in the healthy foods and snacks markets has driven the requirement for not only attractive presentation, but also extended shelf life for products such as organic fruit, vegetables, nuts, dried fruit and cereals. The freshness of these products is largely determined by air-ventilation and the preservation of humidity within the packaging.

An additional requirement has arisen for multi-chamber trays used for multi-component snacks, where each chamber requires perforating differently to optimize the storage life of the ingredients within that particular chamber. Lasers are increasingly becoming an integral part of the production process.

The packaging materials used in these applications are often produced in a continuous process and at high speeds. To maximize the efficiency of the packaging film, it is essential that the laser-produced holes are of the accuracy required to allow the specified air exchange to take place. If not properly controlled the laser perforation process could produce oval or inconsistent shapes and sizes, rendering the material inefficient at best and at worst, unusable.

To eliminate inconsistency problems and match web speeds which can reach 500 m per minute, Rofin has developed laser systems with their Web Movement Compensation System (WMC), which provides solutions for both web direction and cross web applications. In addition, the Rofin system has the capability to control and optimize the perforation hole dimensions, ensuring consistency and further enhancing the shelf life of fresh food products. This means less waste, lower costs, and ultimately more attractive pricing for the user.

Lasers have also proven to be the ideal solution for selective weakening / easy opening applications in packaging. The capability of the laser to “select” a particular film layer(s) to scribe enables the generation of precise easy opening tear lines, while leaving other layers that protect the product from light and humidity, intact. Rofin lasers can even be used to scribe freeform lines, for example following a contour on the print, therefore providing new inspiration and ideas for packaging designers. Laser generated easy open features, which can have as many as 50 holes/cm, provide a consistent opening force, avoiding the spills and even minor injuries which can result from the sometimes inconsistent quality of mechanically created opening features.

Clearly, the not so humble hole, generated in millions every day by Rofin lasers, plays a significant part in our everyday lives from maintaining the freshness of food.

Source: Rofin