Satt technology allows us to provide our customers with a wide variety of decoration requirements of plastic parts.
In this context the use of PVD technology is aimed mainly at obtaining surface finishes. It is possible to achieve a metallic look (shiny and satin) with remarkable aesthetic characteristics of light reflection that are unachievable with traditional painting.
The final result is very similar to galvanization, with the advantage of being very flexible with regards to the obtainable colors.
The term PVD stands for Physical Vapor Deposition.
With this technique materials such as aluminum, steel, alloys of chromium, copper, gold and silver can be deposited on substrates (tipically made of plastic or zamak).
PVD includes more types of machines in its definition:
- Thermal evaporation
- Cathodic Arc deposition
- Sputtering
Without discussing in detail the merits and flaws of each type of machine, what is central to all these processes is the fact that they produce a "cloud" of metal that spreads in space and wraps the pieces making the coating possible.
In all cases the process takes place inside a closed chamber, in which a high vacuum is generated. Once the vacuum threshold is reached, the metal vapor production phase begins, coating the parts while rotating inside the chamber. The treatment has no environmental impact at all, making it a very ecological option.
The obtained deposit of metal has a very thin thickness (typically on the order of nanometers / micron). Therefore it is of paramount importance to combine it with a protective coating. In fact, in most cases the process is more complex and requires different layers of painting inside which the metal is deposited. PVD coatings are applicable to a wide variety of plastics: PS, ABS, PC, PC / ABS, PMMA, PA ... (and not only: zinc alloy for example).
By integrating multiple technologies it is possible to achieve a very wide range of colors: silver, chrome, steel, copper, and many colors both in gloss, satin or metallic effect. Because of the constraint given by the size of the chamber, the technology is suitable for medium-small size parts.
PVD vs galvanic coatings
From what can be derived in the relevant sections, the enormous problems of galvanic chrome-plating plants in relation to the risks to the workers health and the environmental impact clearly emerge.
The substances used are in fact very dangerous and should be handled with great care. The costs of disposal and water management are high and it is now extremely difficult to obtain the necessary authorizations for the installation of new plants.
PVD coatings, in contrast, exhibit zero environmental impact with regards to the deposition of metal and very limited impact of the painting operations, thus being an alternative of great interest considering the always increasing sensitivity towards the environment and the working conditions.
Even with regards to the materials that can be coated PVD treatments have certain benefits. They can be applied to a wide range of polymers, zamak, and glass. While galvanized coatings are essentially confined to only ABS and PC / ABS.
Another advantage of PVD coatings is given by the range of colors available, ranging from metallic effects to colored finishes.
However, in terms of duration of the coating, the chromium-plating presents better characteristics of resistance to scratching and chipping. Thus it a better option in very severe applications (eg. front grills of cars), both internally and externally.
PVD treatments are recommended only for indoor or modest outdoor use.
Chromium plating can also be performed on very small and very large parts (depending on the size of the tanks), while PVD is limited to the size of the high vacuum chamber.
In conclusion, each technology has advantages and disadvantages that need to be assessed in relation to the type of product that needs to be produced, the operating conditions and the sensitivity about environmental pollution.
