Разработка ионно-плазменной технологической установки для нанесения функционального покрытия на крышки масляных фильтров, страница 6

Then if to be set by time for which the tray with products will move from a compartment for cleaning to a compartment for drawing the covering, equal 1 minute, and distance between these compartments  m we shall receive tray moving speed of 0.2 m/min or 12 km/h. At such speed covering by thickness of 0,5 microns should be deposited on each product in time no more than 0,058 hours.

2.2 Definition of technological process modes

During production process (manufacturing, processing, storages) on the detail surface arise pollution - extraneous substances which presence on a surface is undesirable or is harmful.

The surface condition before plating defines quality of depositing layer and many functional characteristics of coverings.

The detail preliminary passes visual inspection on presence of cracks, having chopped off, hollows. If such are available, the detail is rejected at once.

Technological process of deposition of covering includes following basic stages:

Chemical clearing of a substrate surface;

Clearing of products surface in vacuum;

Covering deposition of on products surface.

For simplification of sprayed metal atom access to the surface it is necessary to remove a film from pollution available on it and the adsorbed gases. Clearing consists in removing from the layers surface of organic pollution: the rests of oils, prints of fingers and fat stains [5].

All chemical methods of details clearing   can be divided on two basic groups [6]:

1)       The methods based on application of neutral solvents which do not destroy molecules of pollution, and owing to sorption activity supersede them from a surface in a solution; thus in solvent the system is formed homogeneous stable molecular-disperse (colloid).

2)       The methods based on application of chemically active liquids (acids and alkalis) and electrolytic processes which destroy molecules of pollution and simultaneously influence the details material.

Application for clearing details of the first group  methods is most desirable, as thus is better the form and the sizes of details are kept; but these methods are not always universal, as there are pollution, on which solvents operate very poorly, leaving on details surfaces thin film of pollution. In this connection in neutral solvents it is necessary to supplement washing of details sometimes (or even completely to replace) with etching in chemically aggressive liquids, it is frequent even with application electrolysis, aspiring thus to the least influence on the details material. The final stage of such clearing - removal of chemically active liquid - consists in application of solvent, more often waters.

Active methods of clearing have, in comparison with clearing in the neutral solvents, following big advantage: together with superficial pollution leaves as well a thin layer of metal which is much saturated by oxides and other pollution.

With application of chemically active liquids and electrolysis it is necessary to carry except for deterioration of details accuracy bubbles formation inside of some metals, filled by hydrogen.

The scheme of technological process is brought on sheet ХАИ.461.06.ДП.12.СГ.01.

2.3 Development of the technological process flow scheme

The First stage of surface preparation before deposition of covering - degreasing of products surface. The greatest distribution to the vacuum industry has received degreasing details in hot trichloroethylene and four-chloride carbon [6]. Both these solvents are inclined to disintegration in presence of water (even in minute quantities) and at heats; products of disintegration - poisonous gas phosgene and a hydrochloric acid. Pairs of trichloroethylene besides possess narcotic action and are unhealthy. Despite of it, usage of  trichloroethylene for degreasing details from nickel, kovar, copper, iron, various alloys and many other things, metals used in vacuum technics, pays off simplicity of operation and its applicability in mass production. Trichloroethylene does not react with the specified metals, and dissolves all fats, oils, pitches, waxes and materials similar to them, not entering with them in chemical reaction that is very important for realization of solvent regeneration. On the basis of this for degreasing a surface of details has been chosen trichloroethylene.