JPH04400A - Plating and production of alumite - Google Patents

Abstract

PURPOSE:To enhance thermal economy and quality and to enhance treatment efficiency by utilizing a heat pump as a heat exchange means for heating and cooling and performing aeration agitation of liquid by a fine porous diffusion cylinder in the case of plating and producing alumite. CONSTITUTION:In plating or production of alumite, a heat pump is used as a heat exchange means for performing heating and cooling in at least one stage such as sulfuric acid degreasing, caustic etching, dyeing and electrolysis. As this heat pump, a type is utilized which discharges hot air or hot water. Thereby heat balance is improved without using a boiler and a refrigerator and less energy consumption is contrived. Aeration agitation is performed for the liquid in the above-mentioned stages by utilizing a fine porous diffusion cylinder made of high-temp. roasted ceramics. The blowout hole of micro bubbles in this diffusion cylinder is preferably regulated to about 50-60mum diameter. Thereby the liquid is extremely homogeneously agitated and treatment time is shortened and also quality of the product is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improvements in plating processes (including both electrolytic plating and electroless plating) and alumite manufacturing methods.

Conventional technology The production of plating and anodizing is a well-known technology, which is currently significantly developed, but there are still many improvements to be made, especially in improving the quality of products, preventing the occurrence of defective products, and saving thermal and electrical energy. Further improvements in reducing the manufacturing time are strongly desired.

Problems to be Solved by the Invention The present invention has conducted various studies on improvements in plating and alumite production, and has found that by using a heat pump, the heat balance during plating and alumite production can be significantly improved. By using a microporous aeration cylinder made of high-temperature fired ceramic, the liquid can be stirred very homogeneously, and the combination of these two new methods improves the quality of the product and saves energy. It has been found that considerable savings can be made and the operating time is considerably shortened.

Structure of the Invention The present invention provides a method for producing plating or alumite,
A heat pump is used as a heat exchange means when performing heating and cooling in one or more of the steps, and a microporous aeration tube made of high-temperature combustion ceramic is used for the liquid during the above steps. The present invention relates to a plating or alumite manufacturing method characterized by performing aeration stirring.

Description of preferred embodiments A preferred embodiment of the present invention will be described.

In the method of the present invention, a heat pump, preferably a special heat pump (cooling heat is discharged as hot water) is used instead of a refrigerator, and the cooling heat is transferred to a relatively low-temperature heating section (sulfuric acid degreasing, caustic etching, dye bath, etc.). ) to save energy.

For the electrolytic cell, instead of using the conventional air agitation with large bubbles, we use a porous porcelain tube made of ceramic or lithium fired at high temperature.
This is a method to obtain a product more than 30% faster in plating and more than 3 times faster in alumite production than conventional methods by bringing microbubbles of ~80μ into continuous contact with the product.

At the same time, micro-agitation is also carried out in the dyeing tank and washing tank.
It is also a method that eliminates defects such as dirt. Applications include alumite manufacturing methods and printed circuit board plating methods, but it is also effective in cleaning.

As an example, a method for manufacturing alumite will be described. -The following operations are performed in the boat-based alumite method.

Loading - Sulfuric acid degreasing - Water washing - Caustic enoting - Water Chemical polishing - Water washing - Neutralization - Water washing - Electrolysis (anodizing) - Water - Dyeing - Water washing - Sealing - Water washing - Drying - Unloading ■ Cooling Electrolysis...・・・ Freezer dyeing
40°C Sealing 95・C In the conventional method, cooling and heating are performed as follows, and electrolysis (
The anodizing bath is cooled to about 20'C using a refrigerator of appropriate capacity. The absorbed heat is dissipated in a cooling tower.

For sulfuric acid degreasing, caustic etching, chemical polishing, dyeing, and sealing, heating is performed using a heater or boiler to reach the required temperature.

Regarding air agitation, electrolytic cells and dyeing tanks require air agitation, but it is usually used by drilling a number of holes of about 1+n/m at regular intervals in a pipe with a diameter of 20m/m to 25m/m. do.

An example of operating conditions is shown below. Current density 0.8-1.2A/d
m', film thickness 15μ, electrolysis time 40 minutes, current density IA/d
m', temperature 20'C0 The general method has the following drawbacks.

■ A refrigerator with the necessary capacity was used for cooling, and a separate heat source such as a boiler was used for heating. The heat lost during cooling is released without being used externally, resulting in a lot of waste in heat engineering.

(2) The current density can only be about 0.8 to 1.2 A/dm' at most, and therefore a long time is required for electrolysis.

(2) There is a large difference between the low current part and the high current part, and this causes a variation in film thickness of 20% to 30%.

■ Dyeing time is long, about 15 to 20 minutes. Also, dyeing properties are poor due to non-uniformity of the film.

■ If the processing temperature is not lower than 20°C, defects such as burning and burning will occur. Temperature control is strict.

According to a preferred embodiment of the method of the invention, the following operations are carried out.

1. When starting up, a boiler can be used to supply a heat source to all necessary locations.

2. Since the electrolytic cell generates heat at the same time as the start-up, this generated heat is supplied to a specific heating tank. Heating by the boiler will be stopped and switched to the heat pump.

3. Since conventional heat pumps discharge cooling heat as air, high-temperature heating (50°C to 60'C) is difficult. Heat pumps that discharge cooling heat as hot water at 60°C to 65°C have a good heat exchange efficiency, so they can be used.

4. If a heating source such as a wheeler is used during the initial start-up, air and water as a heat source for the heat pump are unnecessary. Also, if water is used as a heat source, water will be required, but this embodiment has the advantage that it is hardly needed.

Combined with Heat Bonft Micro Aeration, it has an epoch-making effect in terms of energy saving.

FIG. 1 is a schematic pipe system diagram showing a heating and cooling piping system in an alumite manufacturing method according to a preferred embodiment of the present invention. At the start of production operations (start-up), underground wells (31
) or water from the tap is supplied to the heat pump (31). The heat pump (31) is, for example, a 308P aqua heat pump that discharges hot water. The water mentioned above is piped (
43) and used as hot water as appropriate. Cooling water for the electrolytic cell is supplied to the electrolytic cell heat exchanger (23) through a cold water pump (29), a cold water cushion tank (13), and a cold water pump (27). Heat exchanger (23) 0'
).

The high temperature wastewater returns to the heat pump (11) again.
Used as a heating source. Heat exchanger for acidic degreasing tank (17
), the hot water supplied to the caustic etching heat exchanger (19) and the dyeing tank heat exchanger (21) is supplied to the heat pump (
11), is sent to the heat exchangers (17), (19), and (21) via the hot water pump (30), hot water shoe/dung tank (15), and hot water pump (25).

Let's talk about stirring the electrolyte.

■ In the general method of air stirring, when the rectifier was set to a constant voltage and a current was passed, a current of 800 A flowed.

Therefore, electrolysis is carried out for 40 minutes at a current density of IA/dm'.

2 A micro aeration method using a microporous aeration cylinder according to the present invention will be described. Air stirring was performed using a porous ceramic diffuser tube with a pore diameter of 50 μm to 60 μm, and when a current was applied at a constant voltage of 15 V as described above, a current of 200 OA flowed. Therefore, conduct electrolysis for 40 minutes at a current density of 2.5 A/dm'.

3 The results were as follows.

In Table 1, the temperature is about 20°C in the general method, but according to the microaeration method according to the present invention, it is 28°C to 31°C.
It can be used at a high temperature of about 8°C to 10°C and has an energy saving effect of about 8°C to 10°C.

An example of experimental data is shown.

Table 2 4: In the micro-stirring method according to the present invention, electrical resistance can be lowered by continuously removing Joule heat by continuously surrounding the surface of the alumite product with microscopic bubbles.
A current density 2.5 times higher was obtained. As a result, in order to obtain the same film thickness, less than half the electrolysis time was required compared to the general method, and the variation in film thickness was also very small.

As for dyeability, since a uniform porous membrane was obtained, the dyeability was also good, and a good product was obtained in a much shorter time than with the conventional method. To obtain the same film thickness, a relatively low voltage and short time treatment is sufficient, so the amount of electricity used at that time is 15% to 3.
The energy saving effect was reduced by 0%. Regarding the cooling process, the above-mentioned microporous aeration tube can be manufactured from ceramics, metals, synthetic resins, etc., but in view of its porous nature, heat resistance, and corrosion resistance, ceramics are generally suitable.

Preferably, the porosity is 25-50% and the pore size is 5-50%.
μ.

An example of a microporous aeration cylinder is shown in FIG. The aeration cylinder (76) shown in the figure has a cylindrical shape and is a high-temperature fired ceramic body made of arantum abrasive grains as an aggregate. Diffusion cylinder (76)
A front cover (81) is attached to one end of the cover, and a back cover (83) is attached to the other end. An air (or other desired substance) supply conduit (85) is attached to the back cover (83). The front cover (81) and the back cover (83) are connected to the shaft (87
). Four specific examples of the aeration pipe (26) A, B,
The dimensions and physical properties of C and D are shown in Table 3. However, as is clear to those skilled in the art, the aeration pipe (26)
The shape, dimensions, and characteristics of can vary as desired.

An example regarding the alumite method will be shown.

Example 1 B. The working conditions were as follows.

Electrolyte composition HtSO415V/V% aluminum 4g/ρ Bath temperature 25°C±1°C Bath voltage 18V Bath current 200OA Number of electrolytic cells 5 tank ports Total heat generated by electrolytic cell: approx. 190.000 kcaL
'Hrc The heating locations and conditions were as follows.

Sulfuric acid degreasing 3,200 (60°C, 1 tank Caustic etching 3,000g 55°C, 1 tank Dyeing (A) 3
．． 0OOQ 40°C 1 tank staining (B) 3.00
0Q50℃ 3 tank chemical polishing 3,0OOC10
0°C1 tank sealing hole 5,50012
95°C 2 tanks 2 The required amount of air was as follows.

2728.7kg/Hr (1,766, 879
kca12/Hr) 801.4 kg during operation
/Hr (41,7,972kca12/Hr) The total amount of heat required for sulfuric acid degreasing, caustic etching, and dyeing is approximately 100,000 kcaσ/Hr. If the operation is 8 hours a day, 100,000 kca (!/ HrX 8 Hr = 800,000 kc
aQ/day, and the heating process described above produces 800,000 kca per day.
This results in a reduction in the amount of heat ρ. In addition, 9 as the remainder of the generated heat
0,000kca (!/ H is reused as preheating for chemical polishing and sealing, so 190,000kca1
2 X8 H= 1.520.000kca (!/day savings.

Example 2 The working conditions for this case were as follows.

Electrolyte composition H,5o416V/V% Aluminum 4g/Q Bath temperature 25°C±1°C Time 40 minutes Bath voltage 15V Liquid volume 3.500Q Object material to be treated 1100 Total surface area 802dm'

[Brief explanation of drawings]

FIG. 1 is a schematic pipe system diagram showing a heating and cooling piping system in a preferred embodiment of the alumite manufacturing method of the present invention. FIG. 2 is a longitudinal sectional view of a microporous aeration cylinder used in the present invention. 11... Heat pump: 13... Cold water cushion tank: 15... Hot water cushion tank: 17... Heat exchanger for acidic degreasing tank: 19... Heat exchanger for caustic etching tank;
21. Heat exchanger for dyeing tank: 23... Heat exchanger for electrolytic tank; 25... Hot water pump 27 and 29... Cold water pump: 31.. Underground well: 33... Drainage section; 76.・
・Microporous diffuser cylinder; 81...Front cover: 83...Back cover: 8
5... Conduit, 87... Shaft.

Claims (4)

[Claims] (1) In the plating or alumite manufacturing method, a heat pump is used as a heat exchange means when performing heating and cooling in one or more of the steps, and furthermore, a high temperature fired ceramic is used for the liquid during the above steps. A plating and alumite production method characterized by performing aeration stirring using a high-quality microporous aeration cylinder. (2) The method for producing plating and alumite according to claim 1, wherein the heat pump is of a type that discharges hot air. (3) The method for producing plating and alumite according to claim 1 or 2, wherein the heat pump is of a type that discharges hot water. (4) The method for producing plating and alumite according to claim 1, 2 or 3, wherein the diameter of the microbubble ejection holes of the microporous atomization cylinder made of high temperature fired ceramic is about 50 to 60 microns.