EXPERIENCE | TECHNOLOGY | PASSION
Film Metallisation
The primary objective of the film metallisation process is to increase the impermeability to gas, steam, humidity and light, thus preserving the substrate’s properties.
Film metallisation belongs to a type of process known as ‘P.V.D.’ which stands for Physical Vapour Deposition and consists of evaporating a metal inside a chamber at very low pressure to allow the creation of a very thin, homogenous layer on the base substrate.
The process consists of positioning the film reel (such as OPP, BOPP, CAST, LDPE, MDPE, HDPE, PET, PVC, PS, OPS, CPP, PC, PA, nylon as well as paper, card, carbon fibre textiles, glass fibre textiles, non-woven fabrics and biodegradable film) inside the metalliser where the metallisation process takes place in a high vacuum at approximately 10-4 pascals. During the process, the film passes through specific rollers under which the evaporators are positioned. The evaporators are bars of conductive material that are heated up to the required temperature to evaporate the aluminium wire.
The aluminium evaporation is deposited on the surface of the film during its passage through the machine. The amount of aluminium deposited depends mainly on the quantity of aluminium evaporated and the speed of the film as it passes through the machine.
Typically, the thickness of the aluminium deposited on film ranges from a minimum of 100 angstroms to more than 350 angstroms. Less than 30 milligrams of aluminium per square metre of film. Given the difficulty in measuring such fine thicknesses, in practice it’s more common to measure and quantify the deposit indirectly: either by measuring the surface resistance of a square-shaped sample or by the optical density, which is defined in relation to the transparency of the metallised film.
Sophisticated optical density control systems are installed on our machinery following the evaporators, allowing measurements to be taken and recorded during the processing of the reel.
Once the metallisation phase has been completed, the reels are immediately rewound, i.e. unwound and rewound using machines called rewinders or cutters. During this phase the film can be cut along the edges to remove the selvedge which forms on the edges of the strip and/or cut to make several narrower reels. In fact, in order to keep costs down, it’s preferable to metallise the widest possible reels which in our case is 2400mm, and then cut to them to obtain the desired width to meet the customer’s needs.
Reasons to choose us
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We metallise any type of film
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Maximum width 2400mm
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On time checks
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Very low start/end reel waste
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Our machines are amongst the most advanced
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Experience since 1982
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Always punctual
Film sector quality
Working in quality means satisfying our customers. Our customers’ satisfaction is our satisfaction.
Continuous quality improvement is one of our goals and is a guarantee of performance for our customers.
Metalfilms’ 30 years of experience in the sector is a guarantee of the correct qualitative assessment of the many types of film and the methods adopted for metallisation. As an ISO 9001, ISO 22000 and a chain of custody certified company we carry out the quality controls that are generally requested of us by the customer. In the absence of specific procedures, we adopt our standard procedure, born from the experience of thirty years of work in the metallisation sector, which include the following checks and controls:
Visual checks of the reels on arrival
Even before unloading the delivery trucks, the packaging and the general condition of the truck itself are checked in order to avoid contamination of the film. Then the reels are checked in order to verify the integrity of the film reels and thus conformity to metallisation.
Surface checks
Humidity tests are carried out with special liquids on the surface of the film to check whether it can be metallised.
In the case of low humidity, a pre-treatment can be carried out by means of a plasma system; this is also often used to increase the adhesion of metal on corona-treated films. The equipment is installed on all our metallisers.
Checks during the process
During the metallisation process the optical density is continually checked at specific points and across the entire reel. The operator adjusts the machine parameters in order to obtain the optical density required by the customer. The metallising machines are equipped with photometric heads, 100mm apart, which continually record and graph the values obtained. The graph allows the operator to intervene immediately in adjusting the parameters of the machine. The optical density values of all the reels are archived in order to maintain a record of the product’s processing history.
Rewinding
Once metallised, the film is rewound on special cutters/rewinders to stabilise the film, trim it or cut it, generating multiple reels of a smaller width. During this phase, visual checks are made such as the rewinding of the film, the winding tension etc. In addition, a sample is extracted to perform the metallisation adhesion test and measure the optical density using a laboratory instrument in order to verify that it corresponds to the values requested by the customer.