Splash phenomenathe process of vacuum aluminum plating film production
Splash phenomena in the process of vacuum aluminum plating film production
For a long time, the vacuum aluminum plating film in the production process of splash phenomenon, one is diagnosed with coated aluminum wire Fe, Si content is too high;
2 it is diagnostic for too many impurities in the vacuum.
Research on surface, aluminum plating film surface oxidation film, is the main reason for the splash.
Keywords: splash, the eye of a needle, the oxidation film
One, the introduction of the process of vacuum aluminum plating film production splash phenomenon, cause the aluminum plating film base material (PVC, PET, CPP, etc all kinds of plastic film) burns, needlelike spots, size is not a term called the eye of a needle.
Packing membranes with eye of a needle than a constant density, influence of packaging film barrier function;
In gold and silver thread the needle on the material base, can lead to break.
For a long time, the splash phenomenon is considered of the main quality problems of aluminum plating film industry.
Production of the above problems, for a long time, routinely diagnosed with vacuum indoor impurity is too high, or suspects aluminum wire quality issue - the amount of Fe, Si.
So, use clean vacuum chamber, transfer aluminium wire and transfer the evaporation boat to solve.
Through these measures, there are several reasons above, also received certain effect, but the majority of companies to adopt these measures, flying splash phenomenon still exists, can not fundamentally solve the problem.
The author through a long period of observation, the study found that root cause, is the result of the film coated aluminum wire surface oxygen.
Second, coating aluminum wire in the process of vacuum evaporation in a physical change In the vacuum coating machine, aluminum melting process, there is a wire feed system and evaporation boat to complete evaporation of atomization assembly, one of the evaporation boat electric heating temperature can reach 1800C - 2000C, when the aluminium wire through the wire feeding system, nearly in the evaporation, soften, melt flow for a drip into the evaporation boat, form a small amount of fog at high temperature, due to the oxide film on the surface of the aluminium wire, its melting point and evaporation point and aluminium wire is not the same as the base material, than base material melting point and steamed points more than double, in the absence of complete melting and atomization, aluminum clip in the fog, its molecular weight is much larger than aluminium atomization, big and small, it's temperature is higher than the temperature of the aluminum fog, this is why formation flying.
Third, oxide film Here I'd like to introduce the natural oxidation film, the fresh aluminum, in the process of natural contact with air and water, will naturally form a thin layer of oxide film, and it is the formula for beta AI2O3H2O in dry air, the membrane is about 2.5 ~ 3.0 nm, but in the water, or in damp environment, oxygen in the dry film is produced by two times, the longer the storage time, the thickness of the membrane increase usually generates oxidation film on the second floor, a layer close to the metal surface, another layer of oxide film formation in solid - gas interface.
Table 1: aluminum is placed in the atmosphere after five years of thickness of oxide film atmosphere relative humidity % 52, 72, 85, 100 222 281 378 17101 the thickness of the oxide film?
= 10???M = 0.1 nm
Four, aluminum plating film line production enterprise's response is always described above, the main reason for the formation flying is oxide film on the surface of the aluminum plating film line, and that the formation of the oxide film and natural property, increase the oxidation resistance of aluminium wire and as much as possible to control the thickness of the oxide film, coating aluminium wire is important subject to improve the quality of products production enterprises, the author thinks that, aluminum coating line production enterprises must adopt measures to deal with, set out to do the following several aspects: 1. Strengthen the study of aluminium wire surface oxidation, seek scientific and effective improvement methods (2) to improve packaging, increase the packing sealing performance 3. Drawing after finished product packing immediately, shorten the parking time among 4. Improve the warehouse environment, reduce the humidity of the air warehouse