KR100326394B1 - Ni-Cr FULL AUTOMATIC PLATING APPARATUS AND PLATING METHOD USING SAID APPARATUS - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automated nickel-chromium plating apparatus and plating method, which improves electrical efficiency by improving the shape of a contact portion of a rack and a hanger, and makes coating thickness of the plating layer deposited on the surface of the product uniform and at the same time coating strength. It relates to a plating facility and a plating method improved. Plating equipment of the present invention devised to achieve the above object,

① The shape of the tip of the rack 21 so that the rack 21 can be stably installed on the hanger 22 ' The cross section 22a of the hanger 22 to which the front end of the rack 21 is fitted, with appropriate spacing so as to fit with the rack, 'Form contact portion 23b to prevent wobble between the racks and prevent plating defects caused by short-circuit of the energized state, and ② high voltage at the initial stage to improve the coating power of Cr After applying for a predetermined time, the applied voltage is linearly lowered, and after a certain time, the power of the plating equipment is controlled by the rectifier to maintain the voltage in a standard state. ③ To prevent the occurrence of a bipolar phenomenon, A negative electrode slide bar 31 for determining the time of application of the weak voltage is installed on the vertical movement portion of the unit elevator 30, and ④ with a pump 51 or the like to recover chromium from the wastewater generated during the water washing operation. The exchanger 40 is provided.

Description

Nickel-chromium plating equipment and plating method {Ni-Cr FULL AUTOMATIC PLATING APPARATUS AND PLATING METHOD USING SAID APPARATUS}

The present invention relates to an automated nickel-chromium plating apparatus (apparatus) and a plating method in which the equipment itself is completely unattended so that each work process from the input to the plating object can be continuously performed. And improve the electrical conductivity (efficiency) by improving the shape of the contact portion of the hanger on which the rack is hung, and also improve the coating strength (force) while making the coating thickness of the plating layer deposited on the surface of the product uniform. The present invention relates to a nickel-chromium plating apparatus and a plating method which have improved corrosion resistance and durability.

In addition, the present invention by the ion exchange method, by recovering the nickel and chromium from the wastewater generated in the plating process to prevent water pollution and at the same time, the recovered nickel and chromium can be used again to benefit economically, Nickel-chromium plating equipment and plating method.

8 of the accompanying drawings is a conventional nickel-chromium plating process.

As referred to in the figure, the conventional nickel-chromium plating process is largely composed of a pretreatment step 100, the main step 200, and the post-treatment step 300.

In general, more than 50% of the plating failure rate is caused by the pretreatment process. The defects caused by the pretreatment process include (1) peeling or swelling of the plating layer, (2) unevenness of gloss such as spots and cloudiness, and (3) plating layer. Unevenness (adhesion), pits, corrosion resistance of the plating target due to the occurrence of pinholes, brittleness of the plating film, and the like.

This pretreatment process, although slightly different depending on the material or the plating method of the plating object, usually consists of the following operations shown in FIG.

Degreasing, Cleaning Process (110)

As a work for removing the oil-retaining dirt adhering to the surface of the plating object, there are solvent degreasing, alkali degreasing, electrolytic degreasing (finishing degreasing), emulsion degreasing and mechanical degreasing.

Pickling Work Process (120)

It is a chemical method for removing an oxide film or hydroxide generated on the surface of a plating object with an acid.

Water washing work process (130)

As a step for diffusing the solution of the previous process adhering to the surface of the plating object in a short time, air stirring, forced convection, hot water washing, spray washing and the like are performed to promote diffusion.

Neutralization Work Process (140)

The object to be plated through the pickling process 120 is deposited in an alkaline solution to neutralize the surface.

The plating object obtained with a clean surface through the pretreatment step 100 is nickel-chromium plated in the main step 200.

This main process is composed of the following operations, as shown in FIG.

Nickel Plating Work Process (210)

Nickel (Ni) of a certain thickness is deposited on the surface of the plating object passed through the pretreatment step 100 for the purpose of anticorrosion and decoration.

This operation was conventionally performed by hand, and was carried out at low current density so that an adion could be sufficiently diffused on the surface of the plating object to form part of the metal lattice.

However, in this case, since the particle | grains of a deposited layer (plating layer) have the disadvantage that it coarsens and peels easily, improvement is calculated | required.

Water washing work process (220)

As a work process for washing a film of plating liquid adhering to the surface of a plating object in a short time, there are a parallel type and a series countercurrent type depending on a method of supplying water.

Chrome Plating Work Process (230)

In order to enhance the appearance of the product, it is also carried out to prevent discoloration in the atmosphere and to improve corrosion resistance against acids.

By the way, according to the conventional chromium plating method, the electrical conductivity (efficiency) is extremely low at 15% or less, and the thickness of the coating layer (sedimentation layer, plating layer) is uneven, which adversely affects the durability of the product. That is, if the chromium plating layer is not deposited on the nickel plating layer, the nickel plating layer reacts with the atmosphere and oxidizes, resulting in a deterioration in appearance such as black pattern on the surface of the product. Therefore, the demand for improvement also boils in this field.

Water washing and dewatering work process (240)

Completely dry the surface of the plating object (product).

By the way, in treating the wastewater generated in this work process, conventionally discharged through the sewage pipe as it is, or discharged after the first settling in the sedimentation tank, there was a problem causing water pollution. For reference, the national law stipulates that in the case of hexavalent chromium, the emission concentration should be 0.5 ppm or less.

Therefore, there is room for improvement in this part as well.

In this way, the product which passed through the said main process 200 is packaged and shipped after quality inspection in the post-processing process 30.

9 of the accompanying drawings is a schematic diagram showing a change in plating layer thickness when a product is plated with a conventional plating facility according to the plating method described above.

In general, when the plating layer is laminated on the surface of the object to be plated under a low current density, since more negative charges are disposed at the corner portions than at other portions, the thickness of the plating layer at this portion becomes relatively thicker than other portions.

In particular, looking at the process of laminating the plating layer, as if making a snowman, the thicker portion of the deposition thickness, the faster the deposition rate of the deposition layer.

As described above, there are some disadvantages to be improved in the conventional nickel-chromium plating method, in particular, the conventional plating facilities are manual or semi-automatic, there is a disadvantage that the quality of the product varies depending on the skill of the operator.

In particular, in the conventional plating equipment (apparatus), the contact area between the rack to hang the plating object and the hanger is unstable, and when moving to the next process, the rack swings back and forth around the hanger, and the plating object (product) falls to the ground. Or, the rack hits the edge portion of the plating bath (혀), there was a disadvantage that the rack itself falls on the ground. Therefore, there is an urgent need for improvement.

The present invention has been made to improve the above-mentioned conventional problems, improve the conductivity (efficiency) by improving the shape of the contact portion of the rack and the hanger, the voltage of the applied voltage over time to different Cr It improves the coating power and fully unmanned automatization of the manual or semi-automatic plating equipment, which is now widely distributed in Korea, so that the quality of products can always be maintained at a constant level. It provides a nickel-chromium plating facility and a continuous plating treatment method using the plating facility, which purifies and prevents environmental pollution, and also provides economic benefits by reusing nickel-chromium reduced by this device. There is a purpose. In order to achieve the above object, the present invention has been devised the following means.

That is, ① the rack is mounted on the object to be stably installed in the hanger, the shape of the leading end of the rack ' And the cross-sectional shape of the hanger on which the front end of the rack is hooked with the rack. In the configuration, it was possible to insert and fix in a wedge shape, thereby preventing electrical contact failure in which the power supply was momentarily shorted by shaking while the rack was moving.

(2) In order to improve the coating power of Cr, at first, a high voltage (approximately 7 volts in this embodiment) is applied for a predetermined time, and then the applied voltage is linearly lowered. In the case of the example, by controlling the power supply of the plating equipment with a rectifier so as to maintain a voltage of about 4 volts), the plating failure caused by the decrease in coating power caused by the characteristics of the chromium plating was eliminated.

In addition, for the unattended automation of the plating equipment, an elevator device that moves intermittently was installed.

On the other hand, in the plating equipment of the present invention, the plating object is continuously transferred to the next step, so that a bipolar phenomenon occurs on the surface of the plating object during transfer in the plating bath. This bipolar phenomenon is a technical problem that must be solved because it prevents the plating layer from being formed on the surface of the plating object.

In the present invention, ④ the negative electrode slide to determine the time of applying a weak voltage to the vertical moving portion of the unit elevator, so that the negative object can be disposed on the surface of the object to be plated through the hanger and the rack, just before the object to be plated is deposited in the plating bath. By providing the bar, the low voltage (with resistance) was energized to prevent the bipolar phenomenon while simultaneously eliminating the plating failure (oxidation of the plating layer) due to the high voltage.

Furthermore, in the present invention, by recovering trivalent and hexavalent chromium from the wastewater generated during the washing operation of the water by ion exchange, water pollution is prevented and the amount of wastewater generated is reduced.

1 is a process flowchart of a nickel-chromium plating method according to the present invention;

2 is a layout view of the nickel-chromium plating equipment according to the present invention;

3 is a schematic perspective view showing a coupling portion of a rack and a hanger according to the present invention;

4 is a perspective view of the rack of FIG. 3;

5A is a front view of an intermittent mobile elevator apparatus according to the present invention;

Figure 5b is a side view and enlarged perspective view of Figure 5a,

6 is an explanatory diagram for explaining a recovery process of trivalent Cr and hexavalent Cr contained in the washing water;

7 shows a time-voltage graph versus a conventional time-voltage change graph showing the transition of voltage according to the present invention;

8 is a conventional nickel-chromium plating process chart,

Fig. 9 is a schematic diagram showing the thickness of each layer when the product (plating object) is plated by the conventional plating equipment.

[Description of Drawing Reference]

1, degreasing process, 2, 4, 6, 10, 12, 14 ...

3. electrolytic acid wash process, 5 electrolytic degreasing process,

7 activation process, 9 nickel strike process,

11 ... nickel plating process, 13 ... chrome plating process,

15 ... washing process, 21 ... rack,

22 hangers, 23a, 23b ...

31.Negative electrode slide bar, 41a, 41b ...

51 pump, 61 inlet pipe,

62 ... exhaust pipe.

Hereinafter, a nickel-chromium plating apparatus and a plating method according to the present invention will be described with reference to the accompanying drawings.

1 is a process flowchart of a nickel-chromium plating method according to the present invention.

As referred to in the drawings, the nickel-chromium plating method of the present invention consists of the following processes.

Pretreatment Process (A)

Degreasing step (1) → washing step (2) → electrolytic pickling step (3) → washing step (4) → electrolytic degreasing step (5) → washing step (6) → activation step (7) → nickel strike step (9) → washing process (10)

In the above, the activation process (7) and the nickel strike process (9) are processes that are performed to improve the adhesion between the object to be deposited and the nickel deposition layer during nickel plating in this process, which will be described later, and instantaneously high voltage in the nickel plating bath. Are applied to form a very thin nickel plating layer on the surface of the plating object.

Features and working method of each other process is the same as the conventional example described above.

Main process (B)

Nickel Plating Process (11) → Washing Process (Nickel Plating Solution Recovery Process) (12) → Chrome Plating Process (13) → Washing Process (14) → Hot Water Treatment Process (15) → Dewatering Process (16)

The hot water washing step 15 is a step of completely removing (washing) the plating liquid from the surface of the object to be plated (product) which has passed through the plating bath, and is made of hot water.

On the other hand, since the water used in the above-described washing step 14 contains trivalent chromium and hexavalent chromium, when discharged as it is, it causes water pollution.

In the present invention, in order to prevent such contamination of the water quality, as shown in Figure 6, through the inlet pipe 61 is installed in communication with the water tank, the waste water discharged from the water washing step 14, the hexavalent chromium ion It is introduced into the exchanger (41a) for reduction precipitation, and this water is introduced into the trivalent chromium ion exchanger (41b) for reduction and precipitation. Then, the purified water can be supplied to the water washing tank again through the discharge pipe (62). Configured. Here, reference numeral 51 is a pump.

However, the reduction precipitation reaction of chromium through the ion exchange groups 41a and 41b may be reversed in order. That is, trivalent chromium may be reduced precipitated first and then hexavalent chromium may be reduced precipitated.

On the other hand, the ion exchange resin filled in the ion exchanger (41a, 41b) can be reused by reducing it back to sulfuric acid (H ₂ SO ₄ ) or sodium hydroxide (NaOH) when the lifetime of the ion exchanger.

Post Treatment Process (C)

Since the post-treatment step of the present invention is the same as the conventional one, the description thereof is omitted here.

On the other hand, the plating equipment of the present invention, the plating operation is performed according to the above process sequence, for example, can be arranged in the form as shown in Figure 2 (an embodiment).

FIG. 2 is a layout view of the nickel-chromium plating facility currently carried out by the applicant, and among the unit processes, the washing processes 2, 4, 6, 12, 14 and the nickel plating process 11 are If necessary, it can be divided into several bathtubs.

On the other hand, in the present invention, the washing step (12, 14) disposed after the nickel plating step (11) and the chrome plating step (13) is divided into three or more sets, for example, the previous two sets of roles to recover the plating solution And the later washing tank was to perform the role of pure washing.

Here, the recovery of the plating liquid means that the plating solution can be continuously carried out even if the plating liquid (or chemicals) is not added separately by re-inserting the solution of the bath having a weak concentration into the bath or the plating bath of the previous concentration. It is used. Thus, there is an economic benefit.

In the nickel-chromium plating apparatus shown in FIG. 2, the movement between the respective processes, the movement to the adjacent bathtub, or the position movement in the bathtub is intermittent by the elevator apparatus shown in FIGS. 5A and 5B. )

5A and 5B are front and side views of an elevator apparatus used in the plating apparatus of the present invention, in which a roller is installed on a hanger 22 having a rack 21, and the roller is a guide rod 25. The guide rod 25 is configured to be able to move forward and intermittently by the chain-shaped driving means 26. That is, the guide rod 25 constituting the elevator device is provided. The movement of the rack 21 and the hanger 22 in each work process by the chain drive means 26 is the same as that of the conventional equipment. However, in the present invention, the chain drive means is also used between the work processes. The rack and the hanger are connected to each other so that the chain and the hanger are continuously moved along the entire work process by the chain drive means.

However, as in the present invention, when the plating object (not shown) continuously moves between the respective processes, a bipolar phenomenon inevitably occurs in the plating bath, and this bipolar phenomenon increases the plating defect rate. The solution must be found.

In the present invention, in order to reduce the bipolar phenomenon, a weak voltage is applied just before the plating object is dipped in the plating bath. However, the application of the voltage (time) is performed by the resistor as shown in Fig. 5B. At the moment when the side of the negative electrode slide bar 31 connected to the 32 is in contact with an energizing plate (facing the side of the negative electrode slide bar) attached to one side of the hanger 22 ascending and descending on the guide rod 25. It is configured to be made. That is, in the present invention, in order to change the strong voltage applied to the plating object through the hanger 22 and the rack 21 when the plating object is introduced into the plating bath and taken out of the plating bath, the weak voltage is changed. The resistors of 1 kV and 2 kV were separately installed, respectively, and the weak voltage when contacted simultaneously with the top or bottom of the negative electrode slide bar 31 connected to the resistor 32 shown in spring form in FIG. It was changed to.

7 of the accompanying drawings is a view showing a comparison of the time-voltage change graph according to the conventional method and the change graph of the voltage applied to the plating target through the rack of the present invention.

As referred to in the drawing, in the past, since the voltage was gradually raised to a high voltage state after applying a standard voltage, the metal particles of the plating layer first electrodeposited to the plating object were coarse, and thus the interfacial adhesion was low. Therefore, even if a plating layer is deposited thereon, the plating layer is easily peeled off, and in the case where the shape of the plating object is complicated, the relatively inner portion or the blunt end portion has a disadvantage in that plating is not performed due to poor electrical conductivity. .

However, as in the present invention, when a high voltage is initially applied, the particles of the plating layer deposited directly on the surface of the plating object become fine, and thus the adhesion at the interface is large. Therefore, the coating strength of a product (plating object) is high, and durability and corrosion resistance are excellent. In addition, when a high voltage is initially applied, even in a portion where plating is relatively poor, the plating layer is deposited to some extent, thereby reducing the defective rate.

Such an application form of the voltage may be adjusted according to a user's convenience by a general rectifier, and the time of each step shown in the figure may also be adjusted.

3 and 4 are schematic perspective views for explaining the combined state of the rack 21 and the hanger 22 of the present invention.

As referenced in the figure, the rack 21 of the present invention has an upper end ' It is bent in the form of ', and the groove 22a of the hanger 22 is formed with a contact portion 23b in the form of a groove so that the upper end of the rack 21 can be stably hung.

therefore, ' The contact portion 23a of the upper end of the rack 21 bent in the form of 'is caught by the contact portion 23b formed on the hanger, so that it does not shake back and forth during movement, and the energized state is also good.

As described above, in the nickel-chromium plating facility constituted according to the present invention, the labor cost can be reduced because the movement between the processes is performed continuously.

In addition, all processes (processes) are carried out regularly under a predetermined condition, there is an advantage that the plating state of the product can be kept constant.

In addition, unlike the prior art, by applying a voltage in the form of weak voltage → high voltage → standard voltage, it is characterized by improving the coating force of the plating layer, excellent durability and corrosion resistance of the final product.

In addition, the wastewater generated in the water washing process is reprocessed by the ion exchangers 41a and 41b, and the purified water is returned to the water washing process again, and only the metal particles precipitated in the ion exchanger are collected and disposed of, thereby reducing environmental pollution. There is an advantage that it can.

Claims (5)

In nickel-chromium plating equipment, Conventional elevator apparatus having a plurality of tubs for each work process and a chain drive means 26 and a guide rod 25 equipped with a hanger 22 on which the rack 21 is hanged on the work process. It is installed throughout the entire process line, the rack 21 and the hanger 22 is characterized by plating the product with unmanned automation while continuously moving between the bath tub of each process. Nickel-chromium plating equipment. The method of claim 1, The contact portion 22a of the hanger 22 moving up and down along the guide rod 25 is hooked to a contact portion 23a, 23b formed in a hook shape at one end of the rack 21, and the rack 21 The contact portions 23a and 23b are bent at a certain angle, and the contact portions 22a of the hanger 22 are configured at the same angle as the contact portions 23a and 23b of the rack 21, The cathode slide bar 31 is installed on both sides of the unit elevator moving up and down along the guide rod 25 so as to apply a weak voltage just before the rack 21 is deposited in the plating bath. Chrome plating equipment. The method according to claim 1 or 2, Among the tubs constituting the plating facility, the tub disposed in the last washing process 14 is characterized in that the inlet pipe 61 and the discharge pipe 62 are installed by installing ion exchangers (41a, 42b) and pumps installed in succession, respectively. Nickel-chromium plating equipment. In the nickel-chromium plating method which consists of a pretreatment process (A), this process (B), and a post-treatment process (C). The pretreatment step (A) is followed by a degreasing step (1), followed by a washing step (2), an electrolytic pickling step (3), and a washing step (4), followed by an electrolytic degreasing step (5) and a washing step (6) in a nickel plating bath. It further includes an activation process (7), a nickel strike process (9), and a water washing process (10) for instantaneously applying a high voltage. This process (B) removes the plating liquid from the surface of the object to be plated in hot water after the nickel plating process (11) → washing process (nickel plating solution recovery process) (12) → chrome plating process (13) → washing process (14). Nickel-chromium plating method further comprising a hot-water washing step (15) and a dehydration step (16). The method of claim 4, wherein In the nickel plating step (11) and the chrome plating step (13), the nickel-chromium plating method, characterized in that the voltage is applied to the plating object in the form of weak voltage → strong voltage → standard voltage.