The possibility of electronic sensing under any angle, the possibility to read at 20% contrast of marking signs relative to the surface (for a linear bar-code it is required not less than 80-90% of contrast) refer to the advantages of matrix marking, Data Matrix, for example; the possibility to dimensional scaling and distant reading are available. In a square marking sized some millimeters only, up to 2335 alphanumeric signs can be put. Actually, it is a portable database.
One of effective conductive surfaces´ marking methods is electrochemical marking (ECM). Typical installations of ECM use solid tool-electrodes (TE) and a data entry screen with hollows in the image of the picture being marked, there being no electrolytic flow canal; the process is carried out by means of electrolytic damping of a porous layer. It limits the marking depth. Besides, such screens allow to apply a limited number of markings, require special materials and printers or using photolithographic methods for stamping.
The installations having the minimized and equal interelectrode-gap gage (IEG), along the whole surface and providing the conditions for the uniform electrolytic flow allow actualizing the ECM advantages to the full extent. The useful area of the developed by us TE for ECM with matrix notation sized 10x10 elements is a flat die made by the ends of isolated copper conductors of 0,35 mm diameter which are disposed in the form of a rectangular screen. The IEG is 0,1-0,2 mm, the electrolyte being prepared on the basis of sodium chloride or sodium nitrate.
We also developed a method of TE units´ commutations with photo-elements´ use which doesn´t contain mechanical circuit changers and without using complex programming devices. Every TE unit was connected with a photo-resistance on a flat panel through a reinforcing agent, and the disposition of the photo-resistances corresponding to every TE unit. The treatment was carried out by direct or alternate (for blackening) current. To do it a light image, in correspondence to which the commutation and current passage through TE units was carried out, was projected on the photo-elements´ die through a light-sensitive film or a photomask on the photocell matrix. The signs´ depth was 0,2 mm at the processing time of 40 sec., that is sufficiently higher than the mask methods of ECM.
The article is admitted to the International Scientific Conference " Modern High Technologies "; Egypt, Hurgada, February, 21-28, 2007; came to the editorial office on 11.01.07