Plating equipment

One. Classification of electroplating processes:

Acid Bright Copper Plating Nickel/Gold Electroplating Tin

Two. Process flow:

Acid picking & rarr; full plate electroplating copper & rarr; graphic transfer & rarr; acid degreasing & rarr; secondary countercurrent rinsing & rarr; micro etch & rarr; secondary

→ soaking → tin plating & rarr; two-stage countercurrent rinsing

Countercurrent rinsing & rarr; pickling & rarr; graphic electroplating copper & rarr; two-stage countercurrent rinsing

→ nickel plating & rarr; secondary washing & rarr; dip citric acid & rarr; gold plating & rarr; recycling & rarr; 2-3 pure water washing & rarr; drying

three. Process Description:

(1) pickling

1 Role and purpose:

Remove the surface oxide and activate the surface of the board. The concentration is generally 5%, and some are kept at about 10%, mainly to prevent the sulfuric acid from being unstable due to the introduction of moisture;

2 The acid leaching time should not be too long to prevent the oxidation of the surface; after a period of use, the acid should be turbid or the copper content should be replaced in time to prevent contamination of the copper plating cylinder and the surface of the plate;

3 C.P grade sulfuric acid should be used here;

(2) Full-plate electroplating copper: also called copper, plate, panel-plating

1 Role and purpose:

Protect the thin chemical copper that has just been deposited, prevent the chemical copper from being etched away by acid after oxidation, and add it to a certain extent by electroplating

2 Process parameters of full-plate electroplating copper: The main components of the bath are copper sulfate and sulfuric acid, which are formulated with high acid and low copper to ensure the uniformity of the thickness distribution of the plate during plating and the deep plating ability for the deep hole. At 180 g / liter, the majority reaches 240 g / liter; the copper sulfate content is generally about 75 g / liter, and a small amount of chloride ions are added to the bath, which serves as an auxiliary glossing agent and a copper light agent to exert a gloss effect; copper The amount of light agent added or the amount of open cylinder is generally 3-5ml / L, the addition of copper light agent is generally supplemented according to the method of kiloampere hour or according to the actual production board effect; the current calculation of the whole plate plating is generally 2 A / square The decimeter is multiplied by the electroplatable area on the board. For the whole board, the board length dm× board width dm× 2× 2A/ DM2; the copper cylinder temperature is maintained at room temperature, the general temperature does not exceed 32 degrees, multi-control At 22 degrees, so in the summer because the temperature is too high, the copper cylinder is recommended to install a cooling temperature control system;

3 Process Maintenance:

Daily replenishment of copper light agent according to the kiloampere hour, supplemented by 100-150ml/KAH; check whether the filter pump is working properly, whether there is air leakage or not; use a clean wet cloth every 2-3 hours to connect the cathode conductive rod Scrubbing clean; weekly analysis of copper cylinder copper (1 time / week), sulfuric acid (1 time / week), chloride ion (2 times / week) content, and through the Hall cell test to adjust the light agent content, and Timely replenish relevant raw materials; clean the anode conductive rods every week, electric joints at both ends of the tank, timely replenish the anode copper balls in the titanium basket, use low current 0. 2 & mdash; 0. 5ASD electrolysis 6 & mdash; 8 hours; monthly inspection Whether the titanium basket of the anode is damaged or not, the damaged one should be replaced in time; check whether there is anode mud accumulated at the bottom of the titanium basket, if it should be cleaned up in time; and continuously filter 6&mdash with carbon core; 8 hours, while low current electric discharge Every six months or so, depending on the contamination of the bath, it is decided whether large treatment (activated carbon powder) is required; the filter element of the filter pump should be replaced every two weeks;]

4 large processing procedures: A. take out the anode, pour the anode out, clean the anode surface anode film, and then put it in the barrel of the copper anode, roughen the copper corner surface with a micro-etching agent to even pink, wash and dry After that, put it into the titanium basket and put it into the acid tank for standby. B. Put the anode titanium basket and the anode bag into 10% lye soaked in 6— 8 hours, rinse with water, then soak with 5% dilute sulfuric acid, rinse with water. After the reserve; C. Transfer the bath to the spare tank, add 1-3ml / L of 30% hydrogen peroxide, start heating, wait until the temperature is added to about 65 degrees to open the air and stir, the air is stirred for 2-4 hours; Turn off the air agitation, slowly dissolve the activated carbon powder into the bath according to 3— 5g/L. After the dissolution is complete, turn on the air to stir, so keep 2— 4 hours; E. Turn off the air and stir, warm, Let the activated carbon powder slowly precipitate to the bottom of the tank; F. When the temperature drops to about 40 degrees, use 10um PP filter to add filter powder to filter the tank to clean the working tank, open the air and stir, put into the anode, hang Into the electrolytic plate, press 0. 2-0. 5ASD current density low current electrolysis 6 & mdash; 8 hours, G. Analysis, adjust the sulfuric acid, copper sulfate, chloride ion content in the tank to the normal operating range; according to the Hall groove test results to supplement the light agent; H. After the plate surface color is uniform, you can stop the electrolysis, then press 1- 1. The current density of 5ASD is subjected to electrolytic membrane treatment for 1-2 hours, and a black phosphorus film with uniform adhesion and good adhesion is formed on the anode; I. Test plating OK.

5 The anode copper ball contains 0.3% & mdash; 0.6% phosphorus, the main purpose is to reduce the anode dissolution efficiency and reduce the production of copper powder;

6 When supplementing the medicine, if the addition amount is as large as copper sulfate or sulfuric acid; after the addition, it should be electrolyzed with low current; when adding sulfuric acid, pay attention to safety. When the amount of supplement is large (10 liters or more), it should be slowly supplemented several times. Add; otherwise, the bath temperature will be too high, the photolysis will accelerate, and the bath will be contaminated;

7 The addition of chloride ion should pay special attention because the chloride ion content is extremely low (30-90ppm). When adding, the dosage tube or measuring cup must be accurately weighed before adding; 1ml hydrochloric acid contains about 385ppm of chloride ion,

8 Drug Addition Calculation Formula:

Copper sulphate (unit: kg) = (75-X) & times; tank volume (liter) / 1000

Sulfuric acid (unit: liter) = (10% - X) g / L & times; tank volume (liter)

Or (unit: liter) = (180-X) g / L & times; tank volume (liter) / 1840

Hydrochloric acid (unit: ml) = (60-X) ppm & times; tank volume (liter) / 385

(3) Acid degreasing

1 Purpose and effect: remove the oxide on the copper surface of the circuit, the residual glue of the ink residual film, to ensure the bonding force between the primary copper and the patterned copper or nickel plating

2 Remember to use an acidic degreaser here, why not use an alkaline degreaser and the alkaline degreaser is better than an acid degreaser? Mainly because the graphic ink is not resistant to alkali, it will damage the graphic circuit, so only the acid degreaser can be used before the graphic plating.

3 It is only necessary to control the concentration and time of the degreaser during production. The concentration of the degreaser is about 10%, and the time is guaranteed to be 6 minutes. The time is longer and there will be no adverse effect; the replacement of the bath is also working according to 15 square meters per liter. Liquid, supplemental addition according to 100 square meters 0. 5 & mdash; 0. 8L;

(4) Micro-etching:

1 Purpose and role: clean the roughened copper surface to ensure the bonding between the patterned copper and primary copper

2 The micro-etching agent mostly uses sodium persulfate, the roughening rate is stable and uniform, and the water washing property is good. The concentration of sodium persulfate is generally controlled at about 60 g/L, the time is controlled at about 20 seconds, and the drug is added at 100 m3 3-4 kg. The copper content is controlled below 20 g / liter; the other maintenance cylinders are the same as the copper etched.

(5) pickling

1 role and purpose:

Remove the surface oxide and activate the surface of the board. The concentration is generally 5%, and some are kept at about 10%, mainly to prevent the sulfuric acid from being unstable due to the introduction of moisture;

2 acid leaching time should not be too long to prevent oxidation of the surface of the board; after a period of use, when the acid liquid appears turbid or the copper content is too high, it should be replaced in time to prevent contamination of the surface of the electroplated copper cylinder and the plate;

3 C.P grade sulfuric acid should be used here;

(6) Graphic electroplating copper: also called secondary copper, copper plating on the line

1 Purpose and role: In order to meet the rated current load of each line, the copper and copper of each line and hole need to reach a certain thickness, and the purpose of copper plating is to thicken the copper and copper of the line to a certain thickness in time;

2 Other items are all plated with

(7) Electroplating tin

1 Purpose and role: The purpose of pattern plating pure tin is mainly to use pure tin as a metal resist layer to protect the line etching;

2 The bath is mainly composed of stannous sulfate, sulfuric acid and additives; the stannous sulfate content is controlled at about 35 g/l, and the sulfuric acid is controlled at about 10%; the tin plating additive is generally added according to the kiloampere hour method or according to the actual situation. Production board effect; the current calculation of electroplating tin is generally multiplied by the plateable area on the plate by 1.5 amps/square metre; the temperature of the tin cylinder is maintained at room temperature, the general temperature does not exceed 30 degrees, and the control is more than 22 degrees, so In summer, the temperature is too high, and the tin cylinder is recommended to be equipped with a cooling temperature control system;

3 Process Maintenance:

Daily replenishment of tin-plated additive according to the kiloampere hour; check whether the filter pump is working properly and there is no air leakage; clean the cathode conductive rod with a clean wet rag every 2-3 hours; Tin cylinder stannous sulfate (1 time / week), sulfuric acid (1 time / week), and through the Hall groove test to adjust the tin plating additive content, and timely supplement the relevant raw materials; weekly cleaning anode conductive rod, tank two End electrical connector; low current 0. 2 & mdash; 0. 5ASD electrolysis 6 & mdash; 8 hours; check the anode bag for damage every month, the damage should be replaced in time; and check whether there is anode mud on the bottom of the anode bag, such as It should be cleaned up in time; continuously filter 6&mdash with carbon core every month; 8 hours, while low-current electricity is removed; every half a year or so depends on the tank liquid pollution to determine whether it needs large treatment (activated carbon powder); filter every two weeks. Pump filter;

9 large processing procedures: A. Take out the anode, remove the anode bag, clean the anode surface with a copper brush, rinse with water, put it into the anode bag, put it into the acid tank, and reserve it. B. Put the anode bag into 10% lye. Soak 6— 8 hours, rinse with water, then soak with 5% dilute sulfuric acid, rinse with water and use for later; C. Transfer the bath to the spare tank, slowly dissolve the activated carbon into the tank according to 3— 5 g/L In the liquid, after it is completely dissolved, adsorb 4-6 hours, use 10um PP filter to add filter powder filter solution to the clean working tank, put into the anode, hang into the electrolytic plate, press 0. 2-0. 5ASD current density low current electrolysis 6— 8 hours, D. After analysis and analysis, adjust the sulfuric acid in the tank, the stannous sulfate content to the normal operating range; supplement the tin plating additive according to the Hall slot test results; E. After the surface color is uniform, the electrolysis is stopped; F. Trial plating OK.

4 When supplementing the medicine, if the amount of addition is large, such as stannous sulfate and sulfuric acid; after the addition, it should be electrolyzed with low current; when adding sulfuric acid, it should be safe, and when the amount of supplement is large (10 liters or more), it should be divided several times slowly. Addition; otherwise it will cause the bath temperature to be too high, stannous oxidation, and accelerate the aging of the bath;

5 drug addition calculation formula:

Stannous sulfate (unit: kg) = (40-X) & times; tank volume (liter) / 1000

Sulfuric acid (unit: liter) = (10% - X) g / L & times; tank volume (liter)

Or (unit: liter) = (180-X) g / L & times; tank volume (liter) / 1840

(8) Nickel plating

1 Purpose and role: The nickel plating layer is mainly used as a barrier layer between the copper layer and the gold layer to prevent the mutual diffusion of gold and copper, affecting the solderability and service life of the board; at the same time, the nickel layer is also greatly increased. Mechanical strength;

2 Process parameters related to full-plate electroplating copper: The addition of nickel-plated additives is generally supplemented by the method of kilo-hours or according to the actual production board effect, the addition amount is about 200ml/KAH; the current of the electroplated nickel is generally calculated as 2 amps/square. Meter multiplied by the plateable area on the plate; the temperature of the nickel cylinder is maintained at 40-55 degrees, and the general temperature is about 50 degrees. Therefore, the nickel cylinder should be equipped with heating and temperature control system;

3 Process Maintenance:

Daily nickel plating additives are added according to the hourly hour; check whether the filter pump is working properly and there is no air leakage; clean the cathode conductive rod with a clean wet rag every 2-3 hours; analyze the copper regularly every week. Cylinder nickel sulfate (nickel sulfamate) (1 time / week), nickel chloride (1 time / week), boric acid (1 time / week) content, and through the Hall cell test to adjust the nickel plating additive content, and timely Supplement the relevant raw materials; clean the anode conductive rod every week, the electric joint at both ends of the tank, timely replenish the anode nickel angle in the titanium basket, use low current 0. 2 & mdash; 0. 5ASD electrolysis 6 & mdash; 8 hours; check the anode every month Whether the titanium basket bag is damaged or not, the damaged one should be replaced in time; and check whether there is anode mud deposited on the bottom of the anode titanium basket, if it should be cleaned up in time; and continuously filter 6&mdash with carbon core; 8 hours, while low current electric discharge; Every six months or so, depending on the contamination of the bath, it is decided whether large treatment (activated carbon powder) is required; the filter element of the filter pump is replaced every two weeks;]

4 large processing procedures: A. Take out the anode, pour the anode out, clean the anode, and then put it in the barrel of the nickel corner. Use the micro-etching agent to roughen the surface of the nickel corner to a uniform pink. After washing and drying, install Into the titanium basket, into the acid tank spare B. Put the anode titanium basket and anode bag into 10% lye soak 6 — 8 hours, wash and dry, then soak with 5% dilute sulfuric acid, wash and rinse, and set aside; C. Transfer the bath to the spare tank, add 1-3ml/L of 30% hydrogen peroxide, start heating, wait until the temperature is added to about 65 degrees, open the air and stir, keep the air for 2-4 hours; D. Turn off Air agitation, according to 3 & mdash; 5 g / liter of activated carbon slowly dissolved into the bath, after the dissolution is complete, open the air to stir, so 2 — 4 hours; E. turn off the air to stir, warm, let the activated carbon The powder is slowly precipitated to the bottom of the tank; F. When the temperature drops to about 40 degrees, use a 10um PP filter to filter the filter solution into the clean working tank, turn on the air to stir, put in the anode, and hang into the electrolytic plate. , according to 0. 2-0. 5ASD current density low current electrolysis 6 & mdash; 8 hours, G. by laboratory analysis, adjustment slot The nickel sulfate or nickel sulfamate, nickel chloride, boric acid content to the normal operating range; according to the Hall groove test results to supplement the nickel plating additive; H. After the plate surface color is uniform, the electrolysis can be stopped, and then Electrolytic treatment at a current density of 1-1. 5 ASD for 10-20 minutes to activate the anode; I. Trial plating OK.

5 When supplementing the drug, if the addition amount is large, such as nickel sulfate or nickel sulfamate, nickel chloride, it should be electrolyzed at a low current after the addition; when the boric acid is added, the supplementary amount of boric acid should be put into a clean anode bag. Can be placed directly inside the nickel cylinder;

6 After nickel plating, it is recommended to add a recovery water wash, use pure water to open the cylinder, which can be used to supplement the liquid level of the nickel cylinder which is volatilized by heating, and recover the water and then rinse it with two-stage countercurrent rinsing;

7 drug addition calculation formula:

Nickel sulfate (unit: kg) = (280-X) & times; tank volume (liter) / 1000

Nickel chloride (unit: kg) = (45-X) & times; tank volume (liter) / 1000

Boric acid (unit: kg) = (45-X) & times; tank volume (liter) / 1000

(9) Electroplating gold: It is divided into electroplated hard gold (gold alloy) and water gold (pure gold) process. The composition of hard gold and soft gold bath is basically the same, except that some trace metal nickel or cobalt is added in the hard gold tank. Or elements such as iron;

1 Purpose and role: gold as a precious metal, has good weldability, oxidation resistance, corrosion resistance, small contact resistance, good wear resistance of the alloy, etc.;

2 At present, the electroplating gold of the circuit board is mainly a citrate gold bath, which is widely used for its simple maintenance and simple and convenient operation;

3 The water gold content is controlled at about 1 g/l, the pH is about 4.5, the temperature is 35 degrees, the specific gravity is around 14 brome, and the current density is about 1 ASD;

4 The main added drugs are acid-adjusted salt and basic-adjusted salt for adjusting the pH value, conductive salt and gold-plated supplement additive for adjusting the specific gravity, and gold salt;

5 In order to protect the gold cylinder, a citric acid dip tank should be added in front of the gold cylinder to effectively reduce the pollution of the gold cylinder and maintain the stability of the gold cylinder;

6 After the gold plate is electroplated, it should be washed with pure water as the recovered water. It can also be used to supplement the liquid level of the evaporation of the gold cylinder. After the water is washed, it is washed with two-stage countercurrent pure water. After the gold plate is washed, 10 g/L of lye is added. To prevent gold plate oxidation;

7 The gold cylinder should be made of platinized titanium mesh as the anode. Generally, stainless steel 316 is easily dissolved, causing metal such as nickel-iron-chromium to contaminate the gold cylinder, causing defects such as white gold plating, exposed plating and blackening;

8 Gold tank organic pollution is continuously filtered by carbon core and supplemented with appropriate amount of gold plating additive.


Plating Equipment Management

The equipment required for electroplating is mainly DC power supply, plating tank, anode and power supply lead, as well as plating solution prepared according to certain formula. In order to make the electroplating process of scientific or industrial value, it is necessary to control the electroplating process, that is, to carry out electroplating according to certain process flow and process requirements, and also to use certain auxiliary equipment and management equipment, for example, filtration. Machine, heating or cooling equipment, test equipment, testing equipment, etc.

(1) Rectifier power supply

Compared with other industrial technologies, the equipment of electroplating technology is not only simple, but also has great flexibility. Taking power supply as an example, as long as it can provide DC power, it can be used as electroplating power source, from battery to AC/DC power generation. Machines, from selenium stacks to silicon rectifiers, from thyristors to pulsed power supplies, are all available for electroplating. The power can be determined by the surface area of ​​the product being plated, or it can be determined by the existing power source.

Of course, the formal electroplating process will use a relatively reliable silicon rectification device, and the main indicator is the magnitude and adjustable range of the current value, and the voltage varies from 0 to 15V with current. Depending on the power level, single or three-phase inputs can be used to protect against moisture and heat. Industrial electroplating power supplies generally range from l00A to several thousand amps, and are usually pre-designed according to production capacity requirements. It is best to use single-slot single-use. Do not supply power to multiple plating tanks. If you only test in the laboratory, you can use a small experimental rectifier power supply of 5 ~ 10OA.

In 1993, the Ministry of Machinery Industry organized experts to prepare the standard for electroplating rectification equipment (JB/T1504-1993), and made relevant regulations on the types, specifications and technical parameters of electroplated rectifiers designed and produced in China. With the advancement of power science and technology, in recent years, there have been great improvements in the design and manufacture of rectified power supplies. Many electroplating power supplies have been developed in the direction of multi-function, high power and small volume. Cycle commutation, adjustable pulses, smoothing adjustments, etc. are already common functions. The technical specifications of commonly used air-cooled thyristors are shown in Table 1.

Table 1 Technical specifications of common thyristor rectifier equipment


Output current / A output voltage / V AC input Output accuracy Preset function Dimensions reference length / mm & times; width / mm & times; height / mm
500

500

500

1000

1000

1000

1500

1500

2000

2000

3000

3000

4000

4000

5000

5000

6000

6000

8000

10000

12000 12

24

50

12

24

50

12

24

12

24

12

24

12

24

12

24

12

24

24

24

24 3-phase exchange

(50±1)H2

380V soil 10% voltage control

± 1% current control ± 1% current density

Control 2% preset time maximum

9999min

Maximum preset power

9999A·h 550×400×850

600×450×950

700×550×1150

600×450×950

700×550×1150

700×550×1150

600×450×950

700×550×1150

700×550×1150

850×650× 1350

700×550×1150

850×650× 1350

850×650× 1350

850×650× 1350

850×650× 1350

1000×800×1750

1000×800×1750

1000X800×1750

1200× 1000× 2100

1200× 1000× 2100

1400× 1100× 2100 (2) plating bath

The plating tank for electroplating includes a dedicated tank for each step in the electroplating production. It is not only a plating tank, but also includes a degreasing tank for pretreatment, a pickling tank and a washing tank, an activation tank, a post-treatment passivation tank, a hot water tank, and the like. Since the plating tank is still a non-standard equipment, its size and size have a large space for the equipment. Small to beakers, large to the pool can be used for plating tanks, because as long as the plating solution can be loaded into the device without loss, it can be used for plating tanks, which is the plating tank used in the actual electroplating industry production, and There is no uniform standard, and this situation is not conducive to strengthening plating management.

In the current electroplating enterprises, the size is generally determined only by the capacity, for example, 500L, 800L, I000L, 2000L up to l0000L, 20000L plating tanks. The length, width and height are also determined by the manufacturers themselves according to the size of the products produced and the size of the shop. Therefore, even the same type of plating tanks are not necessarily the same in size.

As for the material of the plating tank, it is also available in various colors. It is made of FRP, useful for hard PVC, and is made of soft PVC lining with steel. It is also made of brick-concrete structure and then lining soft PVC, or plating on the ground. Slots, even the plating tanks made of granite, of course, there are many irregularities in the middle, but it is the real situation in China's electroplating processing industry.

With the entry of foreign investors into China's electroplating market, foreign advanced electroplating equipment and tanks have also begun to appear in China's electroplating enterprises. At the same time, there are already many professional electroplating equipment manufacturers, and the production level of electroplating tanks is also increasing. high. It is believed that with the further deepening of market economy reform, electroplating equipment manufacturers and industry associations and standardization organizations will cooperate in standardizing and standardizing plating tank capacity, which will be an important contribution to electroplating management.

As for the way the plating tank is used, it varies depending on the operation mode of the electroplating production. There are manual process lines that are arranged in a straight line. In the arrangement, there are multiple plating types and various cleaning tanks and pretreatment tanks according to the process. The other is arranged separately by plating, and each plating is a line. It is also arranged according to the site space and the size of the plating tank according to the local conditions. If it is a mechanical automatic production line, it is basically arranged according to the process flow, and requires a large space and preparation and auxiliary work site.

The indicators of common plating tanks can be seen in Table 2.

Table 2 Process Specifications for Electroplating Production Tanks


Plating tank name Solution properties Working temperature Available materials Main and auxiliary equipment configuration
Tank lining heating pipe or cooling pipe rectification

Power supply cathode

Moving loop

Filtration exhaust
Chemical degreasing Alkaline 70～90 Carbon steel Carbon steel - - - +
Electrochemical degreasing Alkaline 70～90 Carbon steel Carbon steel + - - -
Cold water cleaning neutral room temperature plastic - - - -
Hot water cleaning Neutral 70～80 Carbon steel Carbon steel - - - -
Sulfuric acid pickling acid room temperature ~ 60 carbon steel

Plastic plastic ladle plastic, etc. - - - +
Hydrochloric acid pickling acidic room temperature carbon steel

Plastic Plastics - - - + Continued Table


Plating tank name Solution properties Operating temperature / °C Available materials Main and auxiliary equipment configuration
Tank lining heating pipe or cooling pipe rectification

Power supply cathode

Moving loop

Filtration exhaust
Weak acid activation acid room temperature plastic - - - -

Acidic copper plating, nickel

Acidic

Room temperature to 60 carbon steel

Plastic

Plastic

Ladle plastic, etc. + +

- +

—
Alkaline copper plating, alloy alkaline 25 ~ 65 carbon steel plastic stainless steel, etc. + + - +
Acid tin plating acid room temperature plastic + - +
Alkaline tin plating Alkaline 70～90 Carbon steel Plastic Carbon steel + - +
Silver plated alkaline room temperature plastic + + + +
Gold plating acid or alkaline room temperature ~ 60 plastic fluoroplastic glass + - - +
Acid galvanizing acid room temperature plastic + - - +
Alkaline galvanized alkaline room temperature carbon steel plastic + - - +
Bright nickel plating, weak acidity, 50-60 carbon steel

Plastic plastic titanium, fluoroplastic, etc.

+

+

+ -
Chrome plating Acid 45～70 Carbon steel Plastic Titanium, fluorine plastic, etc. + - - +

Electroless nickel plating on steel

Acidic

90～95 ceramic PP fluoroplastic or sleeve groove - - + -

Regarding the size of the plating tank, in the same plating or production line, the same specification of the plating tank should be used, so that the design and construction can save resources, and the metering and management of materials and water and electricity are also convenient, and the plating site is also neat and beautiful.

For the loading of the plating tank, refer to the parameters listed in Table 3.

(3) Auxiliary equipment

In order to complete the electroplating process according to the process requirements, it is not enough to have the power supply and the plating tank. There must be some auxiliary equipment to ensure the normal production of electroplating, including heating or cooling equipment, cathode moving or stirring equipment, plating liquid circulation or filtration equipment. And necessary accessories for plating tanks, such as electrode rods, electrode leads, anode and anode baskets, plating hangers, etc.

Table 3 Average loading of plating bath


Plating solution type per 100mm cathode loading / m2 per 1OOOL plating loading / m2
Acidic and alkaline plating solution 0.3~0.6 0.6~1.2
Decorative chrome plating, anti-seepage carbon plating copper 0.2~O. 3 0.4 to 0.6
Hard chrome plating 0.15~0.2 0.3~O. 4
Aluminum alloy anodizing treatment 0.3~O. 6 0.6~1.2
Various chemical treatments 0.8～1.5 1.6～3.0

Note:

l. The l000mm cathode length in the table refers to the plating tank with a plating tank width and a height of 800mm. If it is larger than 800mm or the plating liquid volume is more than l000L, it should be calculated according to the loading amount of l000L plating liquid.

2. The loading of the bath is also affected by bath stability and heat exchange capacity.

1 heating or cooling device. Since the plating solution needs to work at a certain temperature, it is necessary to equip the plating tank with a heating device. For example, plating bright nickel requires the plating temperature to be kept at 50 ° C, chrome plating requires a temperature of 50 to 60 ° C, and acid bright copper plating or bright. Silver plating requires a temperature of 30 ° C or less. Thus, these process requirements need to be met with heat exchange equipment. For the heating, the direct heating method is generally adopted, that is, a stainless steel or titanium electric heating tube is directly inserted into the plating tank, and some are fixedly installed in the tank without affecting the plating side or the groove bottom of the plating work. For the more corrosive plating solution, it is best to use a Teflon-regulated electric heater. Some plants still use steam for indirect heating.

There is a direct cooling in the cooling, and there is also a way to indirectly cool down. In units where there is no condition to install a cold machine, it is a last resort to use ice cubes to cool down and place ice cubes around the plating tank. If you really need to cool the plating, you should still use a cold machine. The tube of the exchanger should also be made of a material that is resistant to plating corrosion as the heating tube.

2 Cathode moving or stirring device. Some plating or most plating types require the cathode to be in a swing state, which can increase the operating current, make the plating solution play its proper role (usually brightness and dispersion), and prevent the tip and corners. Plated, burnt.

For example, most bright plating such as bright nickel plating, acid bright copper plating, bright silver plating, etc., require cathode movement. Cathodic movement is also a non-standard device, as long as it can make the cathode a linear or vertical reciprocating mechanism, it can be used as a cathode moving device. The amplitude and frequency of movement are generally required to be 10 to 20 times per minute, and each stroke is generally 10 to 20 cm depending on the length of the plating tank. Some plating can replace the cathode movement with mechanical or air agitation. Mechanical agitation is carried out with a mixer made of a corrosion-resistant material, usually driven by a motor, but the speed cannot be too high. Air agitation uses compressed air that has been filtered to remove oil.

3 filtration and circulation filtration equipment. In order to ensure the quality of the plating, the plating solution needs to be filtered regularly. Some plating types also require continuous filtration during work. Filters are commonly used in the chemical industry. Therefore, they are industry-standard equipment, but they are also based on the company's own standards. Filters can be selected according to plating conditions, plating tank size and process requirements. The usual indicator is the hourly flow, for example, 5t/h, lOt/h, 20t/h, etc.

4 necessary accessories for plating tanks. Accessories that must be provided in the plating bath include anode and anode baskets or anode hooks, electrode rods, power connections, and the like. In order to save investment, some factories do not use an anode basket. It is also possible to hook the anode directly into the plating tank with a hook, but at least the anode sleeve is required.

The advantage of using the anode basket is that the area ratio of the anode to the cathode is relatively stable, which is favorable for the normal dissolution of the anode. When the anode metal material is consumed too much and cannot be replenished, the normal plating operation can be maintained for a certain period of time, and at the same time, it is advantageous to fully use the anode head or the like which is dissolved to be small. The anode sleeve is to prevent the anode slag or the anode mud from contaminating the plating solution, but the anode basket makes the anode in a bimetallic state, which increases the power of the anode chemical dissolution, and at the same time, the difference in the quality of the anode basket and the poor conductivity, It will also add difficulties to the management of some plating.

Most of the anode baskets are made of titanium, a few of them can be made of stainless steel or steel, and the anode bags can be made of polyester or other acid or alkali resistant fabric.

The electrode rod is a conductive rod used to suspend the anode and the cathode and is connected to a power source. Usually made of copper rod or brass rod, slightly longer than the plating tank, the diameter is determined by the current, but at least 5cm.

The key to the power cable is to ensure that the required current can be passed. It is best to use a copper plate or a multi-strand cable. In this case, the cross-sectional area must be met.

5 racks. The hanger is the most important auxiliary tool for electroplating processing. It is a tool to ensure that the electroplated product is well connected to the cathode, and it is also a device that directly affects the distribution and working efficiency of the electroplated coating. Now there are professional hanger manufacturers and suppliers, providing common hangers in the industry and designing and customizing hangers according to user needs.

The hanger is usually made of copper as the main conductive rod and brass as the pole. In addition to the conductive connection between the conductive cathode bar and the product, the other parts of the hanger should be coated with a hanger insulating glue to ensure that the current is effectively distributed over the product and that the hanger is plated with a metal coating.

The simplest hanger is a single metal hook. The complicated hangers have double main conductive rods and multi-layer rods, as well as connecting lines with auxiliary anodes.

In order to save investment, some electroplating factories use wire as a hanging device, which is not worth the loss. There are also some non-effective conductive parts that are not coated with insulating coatings. As a result, metal materials and electrical energy are wasted, and product quality is also affected. Therefore, it should be equipped with suitable hangers according to the process requirements. It cannot be considered that only electricity can be passed.