EP2013383B1 - Surface treatment installation for metallic parts, particularly by electrolysis - Google Patents

Abstract

Surface treatment installation (100) for metallic parts including an electrolytic cell (1) comprising a treatment liquid (20) in which the parts to be treated are immersed, characterised in that the parts to be treated are fixed on a pivoting drum (2) such that there is at least one rotation movement for each part in the cell, and in that the cell (1) comprises at least two electrodes (8a, 8b), while the drum is powered by an electrical power supply with polarity opposite to the electrode polarity, through at least one contact pad that is brought into contact on the drum drive ring.

Description

The present invention relates to an improvement in the method of surface treatment of metal parts, by electrolysis and relates more particularly to an electrolysis cell using the principle of immersion and transfer of parts continuously.

The surface treatment of parts by electrolysis is a well known method, which requires the implementation of an electric current for carrying out the treatment.

Electrolysis can be applied to metals, such as anodizing aluminum, anaphoresis which allows the electrolytic deposition of aluminum paint, treatments on steels such as zinc plating, chrome plating, copper plating, nickel plating , cataphoresis, phosphatation, copper treatments such as tinning, but also electrolytic coating treatments on non-metallic parts such as electroplating of plastic parts.

• soit attachés sur des supports placés de façon à rester immobile dans la cuve d'électrolyse. Dans ce cas un contact électrique, comme par exemple un V en cuivre, placé sur le bord de la cuve permet d'apporter le courant aux supports posés sur ce V et de ce fait aux pièces. Par ce procédé pour que le contact électrique reste constant, les supports et donc les pièces doivent rester immobiles. Ce procédé ne permet donc pas d'éviter la formation de bulles d'air et par conséquent un manque de traitement dans les parties creuses de certaines pièces, et il en résulte un défaut d'homogénéité dans le traitement.
• soit mises en vrac dans des tonneaux d'électrolyse. Dans ce cas les pièces traitées en masse sont mises en contact avec une électrode mobile, placée dans le tonneau. L'inconvénient de ce procédé est que les pièces mises en masse et en rotation s'abîment par frottement les unes contre les autres.

According to conventional electrolysis processes, the parts to be treated are:

• are attached to supports placed so as to remain stationary in the electrolytic cell. In this case an electrical contact, such as for example a copper V, placed on the edge of the tank allows to bring the current to the supports placed on the V and thus parts. By this method so that the electrical contact remains constant, the supports and therefore the parts must remain stationary. This method therefore does not prevent the formation of air bubbles and therefore a lack of treatment in the hollow parts of some parts, and results in a lack of homogeneity in the treatment.
• either placed in bulk in electrolysis barrels. In this case, the mass-treated parts are brought into contact with a moving electrode placed in the barrel. The disadvantage of this method is that the parts put in mass and in rotation are damaged by friction against each other.

The object of the invention is then to overcome all or part of the disadvantages of existing methods and implementation facilities, as mentioned above.

For this purpose, the present invention relates to an installation using a method for surface treatment of parts such as hollow parts or the like, in which the parts are immersed completely inside at least one treatment tank. containing a liquid characterized in that each hollow part is immersed by making it rotate so that the air bubbles that can be created inside the tank are driven from the inner wall of said part.

Thus, the metal surface treatment plant according to the invention comprises an electrolysis cell containing a treatment liquid in which the treated parts are immersed, and is characterized in that the electrolysis cell comprises a motor and a drum rotatably mounted in said electrolytic cell, said drum being rotated by said motor via a driving ring of said drum, and in that the workpieces are fixed on a pivoting drum so as to it is done for each piece in the tank, at least one rotational movement, and in that the tank comprises at least two electrodes, while the drum is supplied with electric current of opposite polarity to that of the electrodes, means of at least one contact pad which is brought into contact with the drive ring of the drum.

According to a complementary feature, the tank comprises a set of contact pads, for example two times fifteen pads sandwiching the drive ring of the drum

According to another characteristic, the contact pads are movably mounted in translation towards the flanks of the ring, and are biased in abutment against the corresponding face of the corresponding flank by an elastic system such as a spring.

According to other features of the invention, the two lateral successions of pads are arranged in an arc having the center of the pivot center of the drum, while each of the contact pads is connected to a copper cable or braid connected to the power supply.

Note also that the outer periphery of the drum comprises a succession of slides, intended to receive by sliding cassettes serving as a support for the parts to be treated, and that the slides are equipped with flexible contact blades, which are fixed to the slides, to transmit the electrical contact of the slide to the corresponding cassette and therefore to the parts attached thereto, thus making it possible to perform the electrolysis.

It should be added that the tank comprises a motor designed to rotate the pivoting drum by the cooperation of a toothed wheel (6) with a succession of pins mounted parallel to each other, and between the two flanges of one of the sidewalls of the drum. .

According to another complementary feature, the tank comprises two electrodes connected to a negative or positive polarity, while the drum is fed at the opposite polarity, and that said electrodes consist of aluminum plates.

• La figure 1 est une vue en bout illustrant la cuve de l'invention ;
• La figure 2 est une vue de dessus ;
• La figure 3 est une vue latérale ;
• La figure 4 est une vue similaire à la figure 1, mais sans le tambour.

Other features and advantages of the invention will become apparent from the description which follows with reference to the accompanying drawings which are given by way of non-limiting examples.

• The figure 1 is an end view illustrating the vessel of the invention;
• The figure 2 is a view from above;
• The figure 3 is a side view;
• The figure 4 is a view similar to the figure 1 but without the drum.

According to the method implementing the treatment plant of the invention, each piece is immersed in a tank, making it do at least one rotational movement such that the air bubbles that can be created inside of the tank are driven from the inner walls of said room.

According to the illustrated embodiment, a rotational movement of at least 90 ° is made to each piece, and preferably a rotation of 360 °.

According to this embodiment illustrated, a predetermined number of said parts is placed beforehand on a support or cassette (4) comprising at least one holding member to retain each of them.

According to this embodiment, the part treatment plant with the general reference (100) consists of a tank (1) comprising a drum (2), rotatably mounted inside the latter, along an axis horizontal (X, X '), on which the parts to be treated are fixed.

According to the illustrated embodiment, the drum (2) comprises, at its outer periphery, a succession of slides (3) with an axis parallel to the axis of rotation of the drum, intended to receive for example by sliding the cassettes (4). serving as support for the parts to be treated.

The cassettes are for example those described in the European patent application EP-A-1,433,537 and include a set of part holders for attaching a plurality of pieces to a single cassette.

The tank (1) of the invention comprises a motor for rotating the pivoting drum (2) by the cooperation of a toothed wheel (6) with a succession of pegs (7) mounted parallel to each other, and between the two flanges (10a, 10b) of one of the flanks (10) of the drum, constituting the drive ring.

The tank (1) comprises for example two electrodes (8a, 8b) connected to a negative polarity for electrolysis of aluminum parts. It will be noted that these electrodes (8a, 8b) would be connected to a positive polarity in the case of electrolysis of a steel or copper part.

The drum (2) is advantageously titanium but it could be otherwise as for example plastic for treatments requiring a metal deposition such as zinc coating.

Said drum (2) is fed at the opposite polarity, that is to say positive in the case of anodization.

The electric current is distributed to the drum (2) by means of at least one contact pad (9) which is brought into contact with the drive ring (10) of the drum.

According to one characteristic of the invention, the tank comprises a set of contact pads, for example (9) two times fifteen pads (9a, 9b, 9c, ..... 90), as illustrated more particularly in FIG. the figure 4 .

According to the illustrated embodiment, the electrical contact with the drum is by sandwiching the drive ring (10) between two sets of fifteen pads.

Said contact pads (9) are for example graphite, but could be in another material for other treatments.

Add that each of the pads (9) is movably mounted in translation to the flanks (10a, 10b) of the ring, and is biased against the corresponding face of the corresponding flank by an elastic system such as a spring.

Of course, the two lateral successions of pads are arranged in an arc whose center is the pivoting center of the drum, as appears more particularly in FIG. figure 1 and 4 .

Thus the graphite pads rub on the walls of the moving flank to transmit the current to the entire structure of the drum, including slides (3) by which are retained the cassettes (4).

Each of the contact pads (9) is connected to a copper cable or braid (12) connected to the power supply (13).

The graphite contacts rub on the flanks (10a, 10b) of the drive ring of the drum, thereby transmitting the current to the entire structure of the wheel, the slides (3) serving as support for the cassettes.

The slides (3) are advantageously equipped with flexible contact blades, which are fixed to the slideways, to transmit the electrical contact of the slideway to the corresponding cassette (4) and thus to the parts which are fixed thereto, thus making it possible to realize the electrolysis between the connected parts, polarized in this application example to the positive pole and the electrodes (8a, 8b).

It will be specified that, according to the preferred embodiment, the electrodes (8a, 8b) advantageously consist of aluminum plates polarized at the negative pole.

Add that the aluminum plates constituting the electrodes are arranged for example on either side of the drum near the walls of the tank, and extend parallel to the axis of rotation of the drum.

The tank (1) thus equipped and filled with an electrolytic solution such as sulfuric acid for anodizing aluminum, makes it possible to anodize aluminum parts attached to the cassettes. By this system the electrolysis is performed on parts fixed to cassettes performing a transverse movement and rotation on the wheel, which allows for a continuous electrolysis on moving parts in the treatment tank.

Of course, the invention is not limited to the embodiments described and represented by way of examples, but it also includes all the technical equivalents as well as their combinations.

Claims (11)

1. A treatment installation (100) for treating the surface of metal parts, comprising an electrolysis vat (1) containing a treatment liquid (20) in which the parts to be treated are immersed, characterized in that the electrolysis vat (1) comprises a motor (5) and a drum (2) pivotally mounted in said electrolysis vat (1), in that said drum (2) is driven in rotation by said motor (5) via a drive ring (10) of said drum (10), in that the parts to be treated are fixed to said drum (2) so that it makes each part in the electrolysis vat (1) undergo at least one rotation movement, in that the electrolysis vat (1) comprises at least two electrodes (8a, 8b), and in that the drum (2) is supplied with electric current of opposite polarity to that of the electrodes (8a, 8b) by means of at least one set of contact pads (9) which is brought into contact with the drive ring (10) of the drum (2).
2. The treatment installation (100) as claimed in claim 1, characterized in that the vat comprises a set of two times fifteen pads (9a, 9b, 9c, ... 9o).
3. The treatment installation (100) as claimed in claim 2, characterized in that the electrical contact with the drum takes place by sandwiching the drive ring (10) between two series of fifteen pads.
4. The treatment installation (100) as claimed in claim 3, characterized in that the contact pads (9) are made of graphite and mounted so as to move translationally toward the flanges (10a, 10b) of the ring and are pressed against the corresponding face of the corresponding sidewall by a resilient system, such as a spring.
5. The treatment installation (100) as claimed in claim 4, characterized in that the two lateral successions of pads are arranged in the form of a circular arc having for center the center of pivoting of the drum.
6. The treatment installation (100) as claimed in claim 5, characterized in that each of the contact pads (9) is connected to a cable or to a copper braid (12) connected to the power supply (13).
7. The treatment installation (100) as claimed in any one of the preceding claims, characterized in that the external periphery of the drum comprises a succession of slideways (3) intended for slidingly receiving the cassettes (4) used to support the parts to be treated.
8. The treatment installation (100) as claimed in the preceding claim, characterized in that the slideways (3) are equipped with flexible contact blades (14) that are fixed to the slideways so as to transmit the electrical contact of the slideway to the corresponding cassette (4) and therefore to the parts that are fixed thereto, thus enabling the electrolysis to be carried out.
9. The treatment installation (100) as claimed in any one of the preceding claims, characterized in that the vat (1) includes a motor for rotating the pivoting drum (2) thanks to the cooperation of a toothed wheel (6) with a succession of pegs (7), which are mounted so as to be mutually parallel, and between the two flanges (10a, 10b) of one of the sidewalls (10) of the drum.
10. The treatment installation (100) as claimed in any one of the preceding claims, characterized in that the vat (1) has two electrodes (8a, 8b) connected to either a negative or positive polarity, whereas the drum (2) is supplied with the opposite polarity.
11. The treatment installation (100) as claimed in claim 10, characterized in that the electrodes (8a, 8b) consist of aluminum plates.

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