KR20000061563A - Ni-Cr FULL AUTOMATIC PLATING APPARATUS AND PLATING METHOD USING SAID APPARATUS - Google Patents

Abstract

PURPOSE: A nickel-chrome plating facility and a continuous plating method using the plating facility are provided to improve plating efficiency of chrome and to obtain environmental and economical advantages. CONSTITUTION: For rinsing processes(2,4,6,12,14) and a nickel plating process(11) among respective unit processes are performed by many baths separately according to a need. The rinsing processes(12,14) performed after the nickel plating process and a chrome plating process(13) are performed in at least three baths. In the first two baths, a plating solution is collected while simply rinsing is performed in the latter one bath.

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 contact shape of the hanger that hangs the rack, and also improve the coating strength (force) while making the coating thickness of the plating layer deposited on the surface of the product uniform. And it relates to a nickel-chromium plating equipment and a plating method with improved 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 to use the recovered nickel and chromium to be able 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, the shape of the tip of the rack may be stabilized so that the rack on which the plating object is mounted can be stably mounted on the hanger. "In addition to the shape of the hanger hanger on which the leading end of the rack is fitted so that the rack can match the" "In the configuration, it can be inserted and fixed in the shape of a wedge, thereby preventing electrical contact failure in which the power supply is momentarily shorted by shaking while the rack is 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.

(3) In order to fully unmanned automation of the plating equipment, an elevator device moving in an intermittent manner 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;

5B is a side view of FIG. 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 which are performed to improve the adhesion between the object to be plated and the nickel deposition layer in the nickel plating in this process, which will be described later, and instantaneously in the nickel plating bath. These are processes in which a very thin nickel plating layer is formed on the surface of a plating object by applying a high voltage.

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 the elevator apparatus used in the plating apparatus of the present invention, wherein the hanger 22 provided with the rack 21 can move up and down along the guide rod 25. The guide rod 25 is configured to be able to move forward intermittently by the chain drive means 26. This is the same as before.

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 immediately before the plating object is dipped in the plating bath, and the application of the voltage (time) is performed by the negative electrode slide bar (shown in FIG. 5B). 31 is configured to be instantaneously in contact with the resistor 32. 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. Resistors of 1 Ω and 2 were separately installed, respectively, and the upper and lower ends of the resistor 32 and the negative slide bar 31 shown in spring form in FIG.

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 referred to in the figure, the rack 21 of the present invention has an upper end " It is bent in the form of, and a groove-shaped contact portion 23b is formed in the crosspiece 22a of the hanger 22 so that the upper end of the rack 21 can be stably hung.

therefore, " Since the contact portion 23a on the upper end of the rack 21 bent in the shape is locked to the contact portion 23b formed on the hanger, 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 unmanned automated nickel-chromium plating equipment, A plurality of bathtubs are provided for each work process, and on the work process, an ordinary elevator device having a chain drive means 26 and a guide rod 25 is installed in all process lines. Nickel-chromium plating equipment, characterized in that the plating of the product while moving continuously between the bath (浴槽). The method of claim 1, The hanger 22 which moves up and down along the guide rod 25 and the rack 21 which is latched on the hanger 22 are " "" Is fixed so as not to be shaken back and forth through the shaped contacts 23a and 23b, Nickel slide bar 31 is mounted on both sides of the unit elevator moving up and down along the guide rod 25 so that a weak voltage can be applied immediately 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 and 42b and pumps, respectively. Nickel-chromium plating equipment. A method of plating nickel-chromium on the surface of a product according to the following process. 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) 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) Post Treatment Process (C) 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.