RU2503753C1 - Device for coat mechanical electroplating - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: proposed device comprises shaft, anode, actuating rolls made of abrasive, holders and actuating roll clamps. Note here that it is equipped with top and bottom flanges having electrolyte feed and discharge channels, seal gaskets, drive and driven pulleys connected by belting and spider. Note here that said spider supports shafts running in bearings and confined axially by top and bottom bushes while actuating rolls and pulleys are rigidly secured to and fitted on shafts. Note also one pair of shafts carry drive rolls and pulleys while another pair supports driven rolls and pulleys to allow slip of driven actuating rolls. Note that actuating roll clamp is composed of springs fitted in spider square grooves wherein holder guides fitted with pins displace, said pins limiting said displacement.

EFFECT: higher efficiency and quality.

2 dwg

Description

The invention relates to electroplating and can be used for electrolytic coating on the inner surface of cylindrical parts in a galvanomechanical way.

A device for electrolytic coating (AS USSR No. 1678911, C25D 5/06 from 12/14/89, bull. No. 35 from 09/23/91), containing a bath, a working electrode in the form of a holder with activating elements mounted in mandrels installed with the possibility of rotation and placement inside the product, the product mount and the current lead. In order to expand technological capabilities and improve the quality of coatings by processing products of different sizes and moving activating elements in a radical plane, it is equipped with a shaft and two disks, the mount is made in the form of upper and lower supporting conical covers with center holes connected by vertical uprights. The shaft is mounted concentrically with respect to the covers and connected to the rotation drive. The holder of the activating elements is made in the form of sections, each of which is made in the form of a hollow cylinder, and the activating elements are installed in the mandrels by means of spring-loaded pads placed in the mandrels on a sliding fit along the radius of the cylinder. Each mandrel is attached to the cylinder by a screw, while the holder sections are mounted without clearance on the shaft. At the ends of the extreme sections there are discs for tightening the sections by means of a threaded connection. The shaft is made with threaded sections, and the current lead is made in the form of a contact ring and mounted on the shaft.

The disadvantages of this device include: the intermittent effect of activating elements on the treated surface during deposition of the coating; the need for an electrolyte bath; uneven surface treatment due to the use of several independent activators in one plane; the need to give a certain frequency of rotation to the holder to create centrifugal forces pressing the activating elements to the work surface; restriction of the use of spring materials of activating elements due to their work directly in the electrolyte deposition; the inability to ensure sufficient circulation of the electrolyte and its constant purification from surface activation products.

A device is known for electrolytic coating (AS USSR No. 1634729, C25D 5/06 dated 01.12.88, bull. No. 10 dated 03.15.91), containing a base in which an annular channel, an annular undercut and a central hole are made . A part is installed in the annular groove through the gasket. A tubular anode is fixed in the center of the base, the drain pipe of which passes through the central hole. At the ends of the anode, PTFE plain bearings are fixed, on which a frame is mounted with the possibility of free rotation. The frame consists of upper and lower rings fastened by uprights. On the lower ring of the frame are rectangular blades, through one made elongated and curved in the opposite direction of rotation. A mandrel is pivotally fixed to the stand, the lateral surfaces of which are made at opposite angles to the axis of rotation. An activating element is fixed at the base of the mandrel. The current supply is carried out from the outside of the part using clamps. The part is lengthened by a nozzle, which is pulled together with screeds to the base. At the bottom of the annular channel, an end cam is made, the height of which is equal to the difference in the lengths of the blades.

The disadvantages of this device include: the need to give a certain frequency of rotation of the holder to create centrifugal forces pressing the activating elements to the work surface; the bias of the activating elements relative to the surface being treated due to the peculiarity of fixing their mandrel to the screed; the need to use powerful hydraulic pumps to create the necessary pressure on the blades of the frame; clogging of the surface of the activators with products of the cut layer; incorporation into the applied layer of material cut off by activating elements and abrasive particles.

A device for electrolytic coating is known (RF Patent No. 2155827, C25D 5/06; dated July 16, 1999; bull. No. 25 dated September 10, 2000) containing an electrolytic cell, an activating head, an attachment point of a product, and a current lead. The electrolytic cell is hermetically sealed, the activating head is made in the form of an impeller carrying three levers, with activating elements movably fixed copying the surface to be machined, mounted on a vertical axis in the lower flange of the electrolytic cell, with the possibility of rotation due to the transfer of hydrodynamic energy of the electrolyte stream to the impeller blades, under pressure not less than 0.05 MPa.

The disadvantages of this device include: the need to use powerful hydraulic pumps to create the necessary pressure on the impeller blades of the activating head; clogging of the surface of the activators with products of the cut layer; incorporation into the applied layer of material cut off by activating elements and abrasive particles.

Of the known closest in technical essence (prototype) is a device for electrolytic coating (AS USSR No. 1705418, C25D 5/06 from 03.03.87, bull. No. 2 from 01/15/92,), containing a shaft, anode , an activating element on the holder associated with means for clamping it to the surface to be treated. In order to simplify the design, the means for pressing the activating element to the surface to be machined is made in the form of a parallelogram mechanism, the links of which are movable through a position in which the parallelogram is transformed into a rectangle, and the parallelogram rocker arms are pivotally connected to the shaft with the possibility of movement in the longitudinal plane. The holder is rigidly connected with a connecting rod located parallel to the axis of the shaft, while the parallelogram mechanism is equipped with means for tightening its links in one direction. The preload tool is made in the form of a load fixed on a connecting rod, while the axis of the shaft is located vertically. In order to increase productivity, the activating agent is made of abrasive material in the form of a roller.

The device operates as follows: an anode and a cathode component are installed in a bath with an electrolyte. Activating abrasive elements are placed in the space between them, which due to their own mass, the mass of the holders, plates and additional weights, as well as due to the presence of parallelograms with articulated sides formed by holders, plates and a spider forming the parallelogram rocker arms, can move down parallel to the machined surface cathode-parts and evenly pressed against it. Moreover, during processing of the inner surface of the cathode-part, the sides of the parallelograms formed by the holders are above the sides formed by the cross, which creates a component of gravity of loads and other elements directed from the center of rotation of the shaft and pressing the activating abrasive elements to the inner surface of the cathode-part. Holders with activating elements from the shaft are driven in a circular motion. Moreover, due to the friction forces between the activating abrasive elements and the cathode surface, the activating elements rotate around the axis of the holders and run around the cathode surface. The current is turned on and coating is applied to the cathode surface. After applying the coatings of the required thickness, the current is turned off, the device is removed from the bath and the finished part is removed.

The disadvantages of the device include the need to use a bath with an electrolyte, the lack of the ability to ensure sufficient circulation of the electrolyte and its constant purification from surface activation products, which leads to a decrease in deposition performance, the quality of activation of the cathode surface and the quality of the resulting precipitate.

The invention is aimed at eliminating the disadvantages of the known devices for galvanomechanical deposition of coatings on internal surfaces and, when applied, the following technical result is obtained: increasing the productivity of the deposition process; improving the quality of activation of the cathode surface; improving the quality of the resulting coating; increasing the adhesion strength of the resulting precipitate with the substrate; prevention of dendritic formation at high operating current densities; improving the safety of the device and environmental safety; reduction in the required volume of electrolyte; increased electrolyte circulation rate.

The specified technical result is achieved through the use of the inventive device for galvanomechanical coating on the inner surface of cylindrical parts containing a shaft, anode, activating rollers made of abrasive, holders, means for pressing activating rollers, characterized in that in order to increase productivity, quality of activation the treated surface and the resulting coating, it is equipped with an upper and lower flange with channels for supplying and discharging electrolyte, I seal spacers, driving and driven pulleys connected by a belt drive and a spider, moreover, the spider carries shafts mounted in bearings and limited in axial movement by the upper and lower bushings, and the activating rollers and pulleys are rigidly fixed and arranged on the shafts in such a way that on one pair of shafts located opposite each other, drive rollers and pulleys are mounted, and on the other pair are driven rollers and pulleys, moreover, the means for pressing the activating rollers is springs, nye in square grooves of the cross, which move the guide holder equipped with pins, limiting their movement in the grooves.

When the rotation cross is communicated, the activating rollers are run on the surface to be machined and due to the difference in the diameters of the activating rollers and pulleys connected by a belt drive, as well as due to the different friction forces between the rollers and the activated surface, the driven rollers will slip relative to the machined surface.

In this case, during coating deposition, the treated surface will be activated by destroying the passivating film, which prevents deposition, and dendrite formation at high current densities will also be prevented. In addition, slippage of the driven activating rollers will improve the quality of surface activation, and the rotation of the rollers around its axis when rolling in will eliminate the clogging of the abrasive surface, since a constant change in the surface of the rollers involved in activation and electrolyte washing of the free surface of the rollers is ensured.

Graphic materials.

Figure 1 - General view of the device; figure 2 - isometry of the device with spacing elements.

The device comprises a shaft 1, anode 2, activating driving 3 and driven 4 rollers made of abrasive, holders 5, means 6 for pressing the activating rollers, upper 7 and lower 8 flanges with channels for supplying 9 and removal of 10 electrolyte, sealing gaskets 11, driving 12 and driven 13 pulleys connected by a belt drive 14, a crosspiece 15.

The crosspiece 15 carries shafts 16 mounted in bearings 17 and limited in axial movement by the upper 18 and lower 19 bushings.

The activating rollers 3, 4 and the pulleys 12, 13 are rigidly fixed and arranged on the shafts 16 so that the drive rollers 3 and the pulleys 12 are mounted on one pair of shafts located opposite each other, and the driven rollers 4 and the pulleys 13 are mounted on the other pair.

The means 6 for pressing the activating rollers 3, 4 serves to ensure constant contact of the rollers with the activated surface and is a spring 20 installed in square grooves of the crosspiece 15, along which the guides of the holders 5 are moved, provided with pins 21, restricting the movement of the holders 5 in the grooves.

The device operates as follows. After appropriate processing of the restored part 22 (i.e., machining, degreasing and etching), it, through the sealing gaskets 11, is installed between the upper 7 and lower 8 flanges, forming an electrolytic cell. Then, the crosspiece 15, bearing the holders 5, means 6 for pressing the activating rollers 3 and 4, pulleys 12 and 13 mounted on the shafts 16 and connected by a belt drive 14, together with the shaft 1 and the anode 2, forms an activating head, which is fixed in the chuck of a vertical drilling machine or other drive and is introduced into the electrolytic cell.

Further, an acid-resistant hydraulic pump (not shown) delivers electrolyte from the tank (not shown) through pipelines to the lower flange 8 of the electrolytic cell through channel 9 and, filling it, merges back into the tank through pipelines through the outlet channel 10 of the upper flange 7. The drive is turned on and rotation is communicated to the activating head, while the rollers begin to run on the activated surface and, by cutting the passivating film, abrasive grains carry out activation.

At the same time, from the direct current source “+” the operating current is supplied to the anode 2, through the shaft 1 and the crosspiece 15, and “-” to the workpiece 22, respectively. Next, galvanomechanical deposition of the coating on the workpiece surface takes place.

At the end of coating deposition, the direct current source is turned off and the electrolyte supply is stopped, the electrolytic cell is disassembled, the finished part (with a given coating thickness) is removed, and a new part is put in its place and the process is repeated.

To ensure slippage of the driven activating elements on the surface of the part, it is necessary that the gear ratio of the belt drive is not more than 0.9.

Claims (1)

Device for galvanomechanical coating on the inner surface of cylindrical parts, containing a shaft, anode, activating rollers made of abrasive, holders, means for pressing activating rollers, characterized in that it is equipped with an upper and lower flange with channels for supplying and discharging electrolyte, sealing gaskets, driving and driven pulleys connected by a belt drive, and a cross, and the cross carries on itself shafts mounted in bearings and limited in axial displacement the upper and lower bushes, and the activating rollers and pulleys are rigidly fixed and arranged on the shafts, while on one pair of shafts located opposite each other, drive rollers and pulleys are mounted, and on the other pair are driven rollers and pulleys, with the possibility of slippage driven activating rollers, moreover, the means for pressing the activating rollers are made in the form of springs installed in square grooves of the cross, along which the guide rails of the holders are provided, equipped with pins restricting them to be moved e in the grooves.

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