BOBST Manchester Limited: Clear and opaque barrier coatings from one machine

With many types of packaged foods, consumers prefer to see the contents of the package they are buying. This has to be balanced against the requirements of the packaging.  The packaging must protect the product, be environmentally friendly and cost effective, whilst also being attractive to consumers.

Certain food packaging materials need to have light and ultra-violet barrier to enable the food to stay fresh. Other foods don’t need this light barrier and can be packaged in clear barrier films.

BOBST Manchester (formally General Vacuum Equipment) has launched into the market a vacuum coated clear barrier coating which is a replacement for EVOH, PVOH and PVDC and combines the benefits of a clear barrier coating applied in atmosphere, with the additional advantages of a vacuum coated barrier layer. A distinctive property of vacuum coating is that it requires only a small fraction of the thickness of the equivalent atmospheric coating with the barrier properties of the two being similar. This results in a coating which has a lower cost of production.

BOBST Manchester uses a standard aluminium metallizing machine as a foundation for this process which results in versatility as one machine can be used for two processes without compromise. BOBST Manchester’s technology uses the controlled injection of oxygen into the aluminium vapour stream causing a reaction between the two elements to produce aluminium oxide (AlOx). This compound can be transparent if the process conditions are correctly controlled.

The exciting feature of this process is that a good water and oxygen barrier is achieved without the need for expensive vacuum ancillaries such as plasma guns. The performance of the machine is based on a control loop that constantly monitors the optical properties of the coated substrate and also ties the injection of the oxygen in to the system and in to these properties.

Careful examination and control of these properties can guarantee both the oxygen and water vapour barrier properties across both the width and length of the substrate. This tight control also permits very low usage of process consumables, enabling low cost production of a relatively high priced coating.

The application is available for coating a wide range of films including PET, BOPP, CPP, PLA and other types of plastic films. The coated film can be used for end products including baked goods and microwaveable products.

General Registron Hawkeye

BOBST Manchester has recently launched into the market, General Registron Hawkeye, which is a monitoring system that at full metallizer speed, detects, counts and categorizes pinholes and other defects from 0.1mm upwards. Hawkeye sets the benchmark for in-process control; bringing increases in speed and final product quality.

An OD beam measuring up to 4.5 OD at 25mm pitch with maximum web width of 4m, the design is modular, robust and easy to calibrate with easily replaceable probes. With a simple user interface, the unit can be standalone or integrated into the metallizer control system and gives customers the choice of which functionality they require.

Developed by BOBST’s renowned optical group in Lausanne, Hawkeye is designed and built to the highest standards. When a defect is detected, the operator is alerted and the type of defect is logged.

Hawkeye counts and classifies holes in 3 sizes, the minimum size of detectable holes is between 0.1mm and 0.2mm and the unit can count up to 255 max holes for each category at each sensor, with a sampling rate of 500ms or larger. Any holes detected which are larger than 2mm will be classified as a scratch. The production speed is currently 1000m/min.

Hawkeye also provides easy cleaning, modules that can easily be added or removed as necessary, 100% functionality from 10°C to 45°C and a design that is so stable, it can go for 1 month without calibration and of course, vacuum compatibility. This new product can also be used during the AlOx process to allow greater precision control and quality assurance.

For more information, please visit our website at or email: