Rofin Laser has installed a new system for Ultimate Packaging, a company based in Grimsby UK, that doubles the rate of producing perforations in modified atmosphere packaging materials for foodstuffs, while at the same time inspecting the perforations using machine vision.
As much as 70 per cent of the flexible packaging produced by Ultimate Packaging is used for fresh produce and chilled food, so the production of modified atmosphere packaging (MAP) has become a key part of the company's business. Ultimate Packaging has a specialist technical team that works with its customers to define the perforation pattern required for each application to ensure maximum shelf life. With the pattern of holes established, it is essential that the systems used to produce these micro-apertures not only incorporate reliable methods of controlling and guaranteeing the size and shape of the holes being produced, but are capable of doing so during high-speed production.
When a laser pulse hits fast-moving material, there can be instances where the quality of the resultant hole may not be quite as required. If web speed exceeds certain values, the holes can become visibly oval and there may also be insufficient energy available within the pulse to completely perforate the material. In some cases, material produced at very high speed may not be of the accuracy required to allow the specified air exchange for the packaging and could therefore be deemed unusable.
Rofin-Baasel has been active in the flexible packaging market for more than 10 years and now has more than 200 customers in this sector. It has developed a series of laser systems, with different configurations, to support customers' requirements in scribing (scoring), perforating, and cutting packaging materials.
The system delivered to Ultimate Packaging is based on Rofins’ high speed StarPack Web Direction System which incorporates a 300W CO2 laser, with four individual Web Movement Compensation (WMC) heads. Rofins’ WMC controls the dimensions of the perforation to ensure consistency, which in turn results in longer shelf life for fresh foods. In this configuration, the system installed by Ultimate can accommodate web widths of up to 1300mm with production speeds in excess of 350m per minute, double their previous system.
The vision system, which uses four cameras, captures images in real time and checks hole diameter and percentage roundness. The system will trigger an alarm if a pre-set number of holes are out of specification.