JP3175095B2 - Deburring solution and precision deburring method for aluminum alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to 1100 or 30
0.0006 IN (0.152 mm) to 0.010 IN made of 03 aluminum alloy (JIS AA symbol)
The present invention relates to a deburring liquid for removing burrs generated when a cooling fin or a cooling core of a thin plate (0.254 mm) is formed by electric discharge machining into a required shape, and a method for removing precision burrs.

[0002]

2. Description of the Related Art Electronic devices mounted on aircraft are required to be small, light, and densely packed. For this reason, the technology of miniaturizing components and directly soldering components onto the board surface has become widespread in printed circuit board assemblies (hereinafter referred to as packages) for electrical component mounting. For this purpose, as shown in FIG. 1, the packages 1 and 1 are back-to-back, and a cooling core (or fin) 2 made of an aluminum alloy is inserted therein via a film adhesive 3, 3 to constitute one package (hereinafter referred to as a module). A way to be taken. Reference numerals 4 and 4 are printed circuit boards. FIG. 2 shows a cooling core (or fin) 2 which is a part of the package structure, and a rectangular wave-like projection extending in the air flow direction A is formed on the surface of a base material made of an aluminum alloy. Are arranged side by side in a direction perpendicular to the flow direction of the slab. After the cooling core 2 is processed into a predetermined shape according to the specification of the drawing, it is interposed between the packages 1 and 1. By the way, in order to form such a cooling core 2 into a predetermined size and shape, an electric discharge machine is generally used.
m, a small flash 5 (FIG. 3) is generated, and the flash 5 is 4K in the cooling core 2 for air cooling of the module.
By sending compressed air of g / cm ² or more, there is a problem that a part of the cooling core 2 or the blow-out portion is clogged away from the base material and obstructs the flow of air.

[0003] Therefore, in order to remove such burrs 5, generally, a method such as a mechanical processing (hand finishing) method, a water jet method, an electrochemical processing method, a chemical processing method, or the like is used. I have. However, the mechanical processing (hand finishing) method cannot be performed by the naked eye, and is performed by a file using a microscope.
Since it is a thin plate having a thickness of 0.25 mm, it is difficult to handle it, it is inefficient, and there is a problem that there is an individual difference in a degree of removing burrs. In addition, the water jet method is difficult to completely remove burrs due to the low jet pressure (high jet pressure damages the fin shape), and the electrochemical processing method is for complex shapes such as cores and fins. May cause burns on the electrodes, leading to a decrease in product quality. The chemical processing method is 0.15 mm to 0.25 m.
Although this is the best method used for cores and fins having a thickness of about m, this method also has a problem that the base material is severely eroded and it is difficult to appropriately remove burrs. Therefore, when using the chemical processing method, mechanical processing method, that is, immersion in a solution of nitric acid and phosphoric acid as a finishing treatment after removing the burrs to some extent by hand finishing with a file or the like, A method of chemically dissolving burrs with chlorine gas is generally used.

[0004]

However, the chemical processing method after the above-mentioned mechanical processing method is not only insufficient to completely remove burrs, but also causes roughening of the surface of the aluminum alloy base material. The aluminum alloy is susceptible to corrosion due to the effects of gas and pickling liquid, and as a time-dependent change after deburring, the occurrence of unstable surface conditions such as spots on the base material, unevenness, and discoloration has become a problem. Was.

[0005] Accordingly, the present invention has been made in view of the above-mentioned problems.
An object of the present invention is to provide a deburring liquid and a precise deburring method capable of obtaining a stable surface state without causing stains, unevenness, discoloration, etc. on the surface of an aluminum alloy.

[0006]

Means for Solving the Problems To achieve the above object, the deburring solution according to the first invention is 740 ml of phosphoric acid.
And 60 ml of nitric acid, and 200 ml of pure water was added to make a total volume of 1 liter, to which 2 to 5 g / l of aluminum alloy (2024) powder was added. In the precision deburring method according to the second invention, the temperature of the deburring liquid according to the first invention is set to 90 to 95 ° C., the immersion time in the solution is set to 120 to 130 seconds, and burrs are removed in the liquid. After that, the substrate is washed with water, further immersed in an oxalic acid solution as an aqueous carboxylic acid solution, and then immediately washed with water and subjected to a vacuum heating treatment.

[0007]

In the present invention, 740 ml of phosphoric acid and 60 ml of nitric acid are used.
When the cooling core or the fin is immersed in a debaring solution made up to a total volume of 1 liter by adding 200 ml of pure water to remove the burrs, the burrs are removed. , A stable aluminum alloy surface state can be obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a mixture of phosphoric acid, nitric acid and pure water to which aluminum alloy (2024) powder has been added, and has a capacity of 740 ml of phosphoric acid, oxalic acid and pure water per 1 liter of total weight. , 60 ml and 200 ml are mixed to remove fine burrs of 20 μm or less, then washed with water, further immersed in a 1 molar oxalic acid solution of a carboxylic acid aqueous solution, immediately washed with water, and subjected to vacuum heating treatment. .

[Example] A cooling core (or fin) made of 1100 or 3003 aluminum alloy formed into a predetermined shape by electric discharge machining is applied to a non-etching alkaline degreasing solution (for example, Okite 61 manufactured by Diafloc Co., Ltd.).
B) Dipping for 5 minutes in a degreasing treatment of machine oil or the like. Next, a 202% aqueous solution containing 74% of phosphoric acid and 6% of nitric acid in a volume ratio is used.
4 The mixed solution to which 3 g / l of aluminum powder was added was immersed at a liquid temperature of 95 ° C. for about 120 seconds, then washed with water, further immersed in about 1.0 mol of oxalic acid solution for about 3 minutes, and immediately washed with water did. And 760 mmHg, 12
Vacuum heat treatment was performed at 0 ° C. for 10 minutes. As a result of observing the surface of the cooling core after the burr removal treatment, the burr was completely removed, and the surface was very beautiful without spots, unevenness, discoloration and the like. This cooling solution can shorten the processing time by increasing the nitric acid concentration,
An experiment was conducted on the concentration of the mixed solution that gave the least surface condition because the surface roughness and discoloration of the aluminum alloy surface became remarkable. The results shown in Table 1 were obtained.

[0010]

[Table 1]

As a result, 74% of phosphoric acid and 6% of nitric acid
% Was most appropriate. Also, to avoid excessive etching of the aluminum alloy, the aluminum alloy 202
3 g / l of the four powders was added to the seven types of volume ratio solutions shown in Table 1 above.
The solution added gave good surface condition results.

Next, when the temperature is changed using the solution having the mixing ratio and the deburring removal time is measured, the value varies depending on the degree of the burr. Was.

[0013]

[Table 2]

Here, when the aluminum alloy 2024 material powder is added, it is considered to serve as a buffer (trial and error not found), and excessive etching does not occur. This result was not obtained even if an aluminum alloy powder other than 2024 was added.

If the deburring temperature is increased, the processing time can be shortened, but the danger in safety work increases, and if the temperature is lowered, the processing time becomes longer and the efficiency becomes worse. 120 to 130 seconds at 95 ° C is desirable.

The cooling cores and fins that have been deburred in accordance with the above are immediately washed with distilled water,
After immersion in morphic acid, it was sufficiently washed with distilled water. The cooling cores and fins treated in this way are completely deburred, and no defects such as spots, unevenness, discoloration, etc. are seen on the surface of the base material, and the surfaces left for one month are the same. And it was confirmed that a stable surface state was obtained.

[0017]

As described above, according to the deburring solution for aluminum alloy and the method for precision deburring according to the present invention, since the deburring solution consisting of a mixture of phosphoric acid, nitric acid and aluminum alloy powder is used, It is possible to obtain a stable aluminum alloy surface state after complete deburring and further processing, and it is possible to obtain a certain quality that is more reliable and safer than the conventional method.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a package using cooling fins.

FIG. 2 is a perspective view of a cooling fin.

FIG. 3 is an enlarged plan view of a main part showing burrs of the fin.

[Description of Signs] 1 Package 2 Cooling Fin 3 Film Adhesive 4 Printed Circuit Board 5 Burr

Claims (2)

(57) [Claims] 1. A deburring liquid for chemically removing fine burrs of 20 μm or less generated by electric discharge machining for forming a cooling fin or a cooling core made of an aluminum alloy into a required shape, comprising 740 ml of phosphoric acid. Mixed with 60 ml of nitric acid
A deburring solution, characterized in that 2 to 5 g / l of an aluminum alloy (2024) powder is added to a composition bath having a total volume of 1 liter by adding 1 ml. 2. The deburring solution according to claim 1, wherein the temperature is 90 to 95 ° C., and the immersion time in the solution is 120 ° C.
１３０130 seconds, a method of removing burrs in the solution, washing with water, further immersing in an oxalic acid solution as an aqueous solution of carboxylic acid, immediately washing with water, and performing vacuum heating treatment. .