Coating vacuum

In vacuum coating, the substrate is fed through an entry template into the application chamber and leaves through an exit template. A vacuum pump or pumps generate vacuum in the system. The negative pressure causes air to be pulled into the application chamber through the entry and exit templates. 

Coating Methods, Characteristics, and Corresponding Coating Thickness 

Coating Method Coating Viscosity, Pa.s Coating Speed, m/min (ft/min) Coating Thickness, pm 

Diagram of vacuum coating system. (Whittle, K., RadTech Report, 18, No. 6, RadTech International N.A., p. 18 (2004). By permission from RadTech International, N.A.) 

Organic Coatings Science and Technology, o. II (Wicks, Z., Ed.), Wiley-Interscience, New York, Chapter XII (1994). 

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VACUUM COATING OF OPTICAL PARTS AND OTHER MATERIAL, ETC,... 

Anon., Vacuum Coating of Formed Meta Parts, National Research Corporation, Cambridge, Massachusetts (1959)... 

The quartz oscillator coating thickness gauge (thin film controller) utilizes the piezoelectric sensitivity of a quartz oscillator (monitor crystal) to the supplied mass. This property is utilized to monitor the coating rate and final thickness during vacuum coating. 

According to our experience, coating-related stresses have the most unfavorable effect on the crystal. This effect is particularly pronounced in the presence of gas, e.g. in sputter processes or reactive vacuum coating or sputter processes. If the Z value for solid material is known, it is better to use it than to carry out automatic determination of the auto Z ratio". In cases of parallel coating and coating sequences, however, automatic Z determination is significantly better. 

The instrument models available differ both in hardware and softv/are equipment the simplest unit, the XTM/2, is purely a measuring or display device that cannot control vacuum coating. 

The XTC/2 and XTC/C group can control vacuum coating sources and up to three different coatings of a process (not to be confused w/ith nine different coating programs). In the case of XTM/2, XTC/2 and XTC/C units, the AutoZero and AutoTune functions are not available, and measurement with several sensors simultaneously as well as simultaneous control of two vacuum coating sources are not possible. 

In all vacuum coating methods layers are formed by deposition of material from the gas phase. The coating material may be formed by physical processes such as evaporation and sputtering, or by chemical reaction. Therefore, a distinction is made between physical and chemical vapor deposition ... 

For molded-plastic patls, vacuum coating techniques are increasingly replacing conventional coating methods, such as electroplating. For example, using vacuum coaling methods, automobile reflectors obtain a mirror-like surface, plastic articles in the furniture, decoration, clock and vratch as ell as electronics industry are metal-coated and optical effects are created on articles in the decoration industry. 

Part 4 - Vacuum coating technology Part 5 - Vacuum drying and vacuum 3/76... 

This air causes the coating material to be brought into contact with the substrate. A diagram of vacuum coating system is in Figure 6.5. 

Figure 79 A continuous in-line vacuum coating unit in production (Photo by courtesy of Leybold Limited)...

Vacuum coating of optical parts and other material... 

Quite aside from physical or chemical reactions, an important function served by high vacuum is the provision of collision-free space, such as required in radio and television tubes, and particle accelerators. In these applications, charged particles must travel relatively long distances before reaching their target. Obviously, their path will be unimpeded only when the probability of collision with residual gas molecules is very low. A similar function is served in vacuum coating, where metal vapor is condensed on a suitable substrate some distance from an evaporation source. 

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