Metallization of plastic parts (PVD)
Compelma proposes technologies for metallization of plastic parts, here is a presentation of the different PVD processes and of the machines.
Metallized plastics are used to replace metal objects by plastics with similar properties. Such as abrasion resistance and electric conductivity which are not innate characteristics of plastic. It also makes parts lower in weight and have higher corrosion resistance.
In general we use PEEK, PEI, ABS et PA plastics materials to process by vacuum metallization (Physical Vapor Deposition method ) to realize metal-plated parts. The PC, PET and PMMA are to avoid for metallization.
The most common metal materials for surface treatment are:
- Al ( Aluminum)
- Cr ( Chromium)
- Cu ( Copper Alloy)
- Ni ( Nickel)
- NiCu (Nickel Copper)
- Sn (Tin)
What is PVD?
PVD is the abbreviation of Physical Vapor Deposition. It refers to the practice of using low-voltage and high-current arc discharge technology. It vaporizes the target material, and ionize both the evaporated material and gas under vacuum conditions.
By using the acceleration of electric field, the evaporated material and its reaction products are deposited on the part to be metallized.
PVD versus Traditional Electroplating
PVD coating and traditional electroplating are similar. Both belong to the category of surface treatment. Both are used to cover the surface of another material.
The difference between the two is that PVD coating film layer and the surface of the work-piece have:
- higher adhesion
- higher hardness of the film layer
- better wear resistance and corrosion resistance
- more stable performance than electroplating.
- can be coated with a wider variety of films
- can be plated out of a variety of more beautiful colors
- does not produce toxic or polluting substances.
The characteristics of PVD coating
The PVD coatings are harder and have more corrosion resistant than coatings applied by the electroplating process. Most coatings have high temperature and good impact strength, excellent abrasion resistance and are so durable that protective topcoats are almost never necessary. PVD coating technology can achieve metallic like appearances on the surfaces of plastics
The surfaces metallized using PVD have the following characteristics:
- abrasion resistance
- scratch resistance
- shedding resistance
- cracking resistance
- stable chemical performance
- corrosion resistance
- acid resistance
- oxidation resistance
In the harsh environment such as sun or humidity:
- the color doesn't change
- no shedding or damage
- stable performance
- good cleaning - easy to remove paint and handwriting, no traces left.
It reduces the time and cost required to clean and polish plated brass or gold.
The weight of the metallized part is lower than full metal parts, so it is easier to transport and to manufacture.
It can bend over 90 degrees without cracking or peeling (PVD coating holds high adhesion and durability). Other technologies, including electroplating and spraying, cannot be compared.
PVD technology is mainly divided into three types:
- vacuum evaporation coating
- vacuum sputtering coating
- vacuum ion coating
Principle of PVD by Evaporation
Principle of PVD by Sputtering
Principle of PVD by ion coating
PVD Machine by Evaporation
PVD Machine by Sputtering
PVD Machine by In-Line Sputtering - continuous
PVD Machine by ION
Flow of the PVD Process