Rapid prototype-Commonly used knowledge of Surface Treatment knowledge - vacuum plating
Rapid prototype-Commonly used knowledge of Surface Treatment knowledge - vacuum platingVacuum plating belongs to a kind of electroplating, is in the high vacuum equipment, on the surface of the product coated with a thin metal coating a method of vacuum plating has been most used in foreign countries, in recent years, has been a great development in China, and widely used in various industries
1.PVD is introduced
PVD is a physical meteorological deposition, which deposits gases on the surface of objects through physical phenomena without chemical reactions in the whole process. It belongs to physical changes.
Vacuum is an application of PVD.In fact, the most common application of PVD is vacuum plating, even equating PVD with vacuum plating.
2.Vacuum plating classification
Vacuum plating can be divided into evaporation plating, sputtering plating and ion plating according to different methods.
（1）Evaporation plating in vacuum environment of not less than 1 ~ 2 pa, using resistance heating, electron beam and laser bombardment methods such as heat to evaporate materials to a certain temperature, makes the molecules of a material or the atomic thermal vibration energy over the surface of the binding energy, so that a large number of molecules, atoms, evaporation or sublimation, and directly form a thin film deposition on the substrate.
Generally speaking, it is a method of heating a metal in a high vacuum environment, melting it, evaporating it, and then cooling it to form a metal film on the surface of the sample.
Evaporation plating metal materials including gold, silver, copper, zinc, chromium, aluminum, and so on, which is the most widely used aluminum.
（2）Sputtering plating is the deposition of gas or molecules onto the surface of the plated workpiece to form the required film.
Sputtering is a wide range of materials, any material can be sputtering, especially high melting point, low vapor pressure elements and compounds, sputtering film and substrate adhesion between good, high film density, film thickness can be controlled and good repeatability.
Compared with evaporative plating, sputtering plating has the disadvantages of more complex equipment, high pressure device and slower speed than evaporative plating.
（3）Ion plating is a method combining evaporation and sputtering. The advantages of this method are strong adhesion between the film and substrate, high deposition rate and film density.
3.Application site of vacuum plating
Vacuum plating is widely used, and the main fields are as follows:
（1）Communication products industry: such as mobile phones, telephone, etc.
（2）Digital products, IT industry: such as notebook computers, MP5, GPS, digital cameras, etc.
（3）Toy industry: especially toys with strict requirements for environmental protection.
（4）Lamps and lanterns industry is applied a lot.
（5）Cosmetics industry: such as cosmetics cover.
4.Vacuum plating process flow
The general technological process of vacuum plating is product surface cleaning -- antistatic -- spray primer -- baking primer -- vacuum coating -- spray finish -- baking finish -- quality inspection -- packaging.
The general method of vacuum plating is to spray a layer of primer on the material before electroplating.As the material is plastic parts, when the injection will remain bubbles, organic gas, and when placed will inhale the moisture in the air.In addition, due to the plastic surface is not smooth enough, direct plating of the workpiece surface gloss, gloss bottom, poor metal sense, and there will be bubbles, bubbles and other bad conditions.After spraying a layer of primer, it will form a smooth surface, and eliminate the bubbles and blisters in the plastic itself, so that the effect of electroplating can be shown.
5.Materials and colors suitable for vacuum
Vacuum plating as a result of meteorological precipitation, generally can spray plastic to both back but achieve vacuum plating, such as ABS, PC, PMMA, PET, PS, etc.
The surface color of vacuum degree is not limited. Different surface colors can be drawn by plating different metals, and colorful plating can also be made. Examples are as follows:
（1）Silver: chrome, aluminum, nickel and so on to achieve.
（2）Gold: gold - plated, titanium oxide and alloy.
（3）Black and gun color: compound coated with titanium and carbon.
（4）Local electroplating is convenient, vacuum plating can be used to cover the areas that do not need electroplating.
6.Vacuum layer thickness
The coating film of bagasse farmers is very thin, generally 0.5~2.0μm。
Because the coating is very thin, easy to wear, so the surface of the vacuum coating also needs to spray a UV paint.
The surface treatment thickness of vacuum plating products mainly includes primer, vacuum coating and UV paint, and the total thickness is controlled at about 0.02mm.
Vacuum plating can make the coating non-conductive, referred to as NCVM.
NCVM is widely used in the communication industry. Some plastic parts of mobile phones need electroplating effect due to appearance requirements. However, metal will interfere with the radio frequency signal of mobile phone antenna, thus affecting the ability of mobile phone to receive signals.
8.Vacuum plating has its drawbacks
The advantages and disadvantages of vacuum plating are relative to water plating. The advantages are mainly shown as follows:
（1）There are many electroplated plastic materials.
（2）Can nauseate color plating, rich color.
（3）When electroplating does not change the plastic performance is high, the local electroplating is convenient.
（4）No waste liquid, environmental protection.
（5）It can be used for non-conductive vacuum plating.
（6）Electroplating effect is brighter and brighter than water plating.
（7）Vacuum plating productivity is higher than water plating.
Its disadvantages are as follows:
（1）Vacuum plating failure rate is higher than water plating.
（2）Vacuum plating is higher than water plating.
（3）Vacuum coating surface is not wear-resistant, need UV protection, water plating generally do not over UV.