TWI565546B - A method for micro-electrolytic machining with deionized water - Google Patents

Description

Deionized water microelectrolysis processing method

The invention relates to an electrolytic processing method, in particular to a deionized water microelectrolysis processing method.

The fine molds produced by the micro-mold processing technology are often used to manufacture precision parts such as precision instruments and microelectronics industries, and the micro-dies are often produced by micro-electrolysis processing methods, which generally use an electrolyte-modulated electrolysis. Liquid, but also a micro-electrolysis process using a deionized water. The conventional deionized water micro-electrolysis processing method, as shown in FIG. 1a, includes a workpiece 9 as an anode and a cutter 8 as a cathode. The cutter 8 has a processing portion 81 in the flowing deionized water. and at a voltage of 28V and 2.3A / cm ² of current density, flowing through the electrolytic processing portion 81 with the deionized water between the workpiece 9, the micro electrochemical machining.

However, in this method, while micro-electrolysis processing is performed, a discharge phenomenon occurs between the cutter 8 and the workpiece 9, which results in a large surface roughness and a poor appearance of the pocket obtained by the processing, which is insufficient for use as a precision part. .

Therefore, there is a need for a deionized water microelectrolysis machining method which can produce a pocket having a small surface roughness and a flat appearance or a milling surface of an arbitrary path.

The invention provides a deionized water micro-electrolysis processing method, which can produce a milling surface with a small surface roughness and a flat appearance or an arbitrary path.

A method for micro-electrolysis of deionized water, comprising: disposing a workpiece on an anode, placing a cutter on a cathode, and immersing the workpiece and the cutter in a deionized water, the cutter having a processing portion, the processing portion is oriented The workpiece; and in the flowing deionized water, and at a current density of 20 to 50 V and a current density of 25 to 200 A/cm ² , the tool is subjected to microelectrolysis processing of the workpiece by the processing portion, wherein the flow is The specific resistance of deionized water is 20~120kΩ-cm. Thereby, the possibility of occurrence of a discharge phenomenon in the deionized water microelectrolysis process can be reduced, and a milled surface having a small surface roughness and a flat appearance or an arbitrary path can be obtained.

The processed portion has a spherical shape or a convex aspherical shape similar to a sphere, and the processed portion has a maximum diameter of 0.01 to 1.0 mm. Thereby, the current density distribution can be made uniform to avoid the unevenness of the shape of the workpiece.

Among them, the processing part of the tool performs microelectrolysis processing at a rotation speed of 60 to 1000 rpm. Thereby, the electric field of the microelectrolysis process can be uniformly applied to the workpiece.

The processing portion of the tool is subjected to microelectrolysis processing at a feed rate of 10 to 40 μm/min with respect to the workpiece. Thereby, microelectrolysis processing can be performed at an appropriate time.

Wherein, a current of 50 to 100 mA is applied to the workpiece and the cutter so that the current density reaches 25 to 200 A/cm ² . Thereby, the processing can be performed stably, and the discharge of the electric current is prevented from being excessively generated.

The current is a pulsed direct current with a pulse width of 0.1 to 0.5 μs. Thereby, electrolytic processing can be performed using appropriate energy to avoid over-processing.

Wherein the flowing deionized water comprises an abrasive grain. Thereby, the workpiece can be polished while performing deionized water microelectrolysis processing.

Wherein, the abrasive particles are an alumina abrasive grain, a diamond abrasive grain, a cubic boron nitride abrasive grain or a carbonized cerium abrasive grain. Thereby, the amount of processing for the workpiece can be increased.

The particle size of the abrasive grains is 1.0 to 5.0 μm. Thereby, the passage of the abrasive particles to block the deionized water conduction can be avoided.

In the deionized water micro-electrolysis processing method of the present invention, by appropriately setting the voltage and current density, a milled surface having a small surface roughness and a flat appearance or an arbitrary path can be obtained, and can be applied to manufacture a fine mold.

(this invention)

1‧‧‧Tools

11‧‧‧Processing Department

2‧‧‧Workpiece

21‧‧‧Processing area

(known)

8‧‧‧Tools

81‧‧‧Processing Department

9‧‧‧Workpiece

91‧‧‧Processing area

Figure 1a: Schematic diagram of a conventional tool for microelectrolysis machining.

Figure 1b: Schematic diagram of the shape and electric field of the processed part of the conventional tool.

Figure 2a: Schematic diagram of the shape and electric field of the machining part of the spherical tool.

Figure 2b: Appearance of the processed part of the spherical cutter.

Fig. 3a is a diagram showing the macroscopic topography of the micro-pits produced by the deionized water microelectrolysis processing method of the present invention.

Fig. 3b is a top view of the bottom view of the micro-pits made of alumina added to the deionized water microelectrolysis processing method of the present invention.

Figure 4a: Bottom SEM image of micro-pits made by the deionized water microelectrolysis process of the present invention.

Figure 4b: Bottom SEM image of micro-pits made by adding alumina to the deionized water microelectrolysis process of the present invention.

Figure 5a: Appearance of the deep trench made by the deionized water microelectrolysis processing method of the present invention.

Figure 5b: Surface topography of a deep trench made by the deionized water microelectrolysis processing method of the present invention.

Figure 5c is a bottom profile view of a deep trench made by the deionized water microelectrolysis process of the present invention.

Fig. 6a is a view showing the appearance of a microchannel having a radius of 0.5 mm produced by the deionized water microelectrolysis processing method of the present invention.

Figure 6b: The micro-electrolysis processing method of the deionized water of the present invention has a radius of 1.0 mm The middle surface topography of the flow channel.

Fig. 7a is a view showing the appearance of a square groove produced by the deionized water microelectrolysis processing method of the present invention.

Figure 7b: Surface topography of the square groove produced by the deionized water microelectrolysis processing method of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt; The deionized water micro-electrolysis processing method comprises: using a workpiece 2 as an anode and a cutter 1 as a cathode, the cutter 1 having a processing portion 11 having a processing region 21, the cutter 1 The processing portion 11 can face the processing region 21, and the processing portion 11 and the processing region 21 can be relatively moved. For example, the processing portion 11 can be moved according to a predetermined movement path, and the processing portion 11 can be processed. Area 21 is machined to form a projected shape.

The method for microelectrolysis of deionized water according to the present invention further comprises: subjecting the tool 1 to microelectrolysis processing of the workpiece 2 by the processing portion 11 in flowing deionized water at a predetermined voltage and current density. In detail, the deionized water flow system can wash away the sludge generated by the processing, prevent the sludge from accumulating in the processing region 21, hinder the micro-electrolysis processing, and update the ratio of the micro-electrolysis processing in the processing region 21 The deionized water whose resistance value changes. Moreover, a circulation tank can be installed to circulate the deionized water, and the deionized water is set to be circulated for a specific time to replace the deionized water, thereby reducing the amount of the deionized water.

Further, the line voltage may be 20 ~ 50V, the current density is based may be 25 ~ 200A / cm ^2, if the voltage is greater than 50V can easily lead to the occurrence of the deionized water dielectric discharge phenomenon caused by the collapse, and the tool wear 1 On the other hand, if the voltage is less than 20 V, the current density due to the microelectrolysis process generated is too low, and the abnormal retraction is likely to occur, and the smooth processing cannot be performed smoothly. Moreover, if the current density is greater than 200 A/cm ² , the deionized water is prone to discharge, resulting in a pitting mark at the bottom of the processing region 21, and if the current density is less than 25 A/cm ² , The current density is too low, which may cause abnormal retraction and cannot be processed smoothly.

Further, in the deionized water microelectrolysis processing method of the present invention, a current of 50 to 100 mA can be applied, and the design and size of the tool 1 described later can be appropriately matched to achieve a current density of 25 to 200 A/cm ² . The processing can be stably performed to avoid the excessive energy generated by the current to generate a discharge phenomenon. If the current is greater than 100 mA, the deionized water is prone to discharge, and the micro-electrolysis processing of the deionized water cannot be performed. If the current is less than 50 mA, the microelectrolysis processing of the deionized water is difficult to occur because the energy supplied is too low.

Moreover, the current system can be a pulsed direct current. By using the pulsed direct current, the circuit can be processed when the circuit is in the path, and the sludge deposited in the processing region 21 can be removed during the disconnection to avoid excessive mud. When the slag is deposited to hinder the progress of the deionized water microelectrolysis process, and the deionized water flows slowly, the sludge can be sufficiently removed by the time of the disconnection. Moreover, the pulsed direct current preferably has a pulse width of 0.1 to 0.5 μs, and since the pulse width is proportional to the energy of the microelectrolysis process provided by the current, by setting the pulse width to be within the range, the pulse width can be used. If the pulse width is greater than 0.5 μs, the workpiece 2 is excessively processed. On the other hand, if the pulse width is less than 0.1 μs, the abnormal retraction is likely to occur, and the tool 1 is easily removed. The feed depth cannot reach 0.01 mm, and abnormal retraction causes pitting on the surface of the processing region 21. Moreover, the pulse breaking time is preferably 0.2 to 1.0 μs, whereby the deionized water for flowing can appropriately remove the sludge, and if the pulse breaking time is more than 1.0 μs, the microelectrolysis processing efficiency is lowered, and On the one hand, if the pulse breaking time is less than 0.2 μs, the removal effect of the sludge is insufficient, and after a long time of processing, the sludge may be deposited to hinder the progress of the micro-electrolysis process.

Moreover, the specific resistance value of the deionized water may be 20 to 120 kΩ-cm, thereby reducing the possibility of discharge of the deionized water during microelectrolysis processing, if the specific resistance value When it is larger than 120 kΩ-cm, discharge phenomenon is likely to occur, and it is difficult to perform microelectrolysis processing of the deionized water. On the other hand, if the specific resistance value is less than 20 kΩ-cm, the deionized water is made as the sludge accumulates. The concentration of the conductive ions is too high to perform microelectrolysis processing.

In addition, in the deionized water micro-electrolysis processing method of the present invention, the tool 1 can be designed to improve the electric field design in the micro-electrolysis process. The surface of the workpiece 9 processed by the conventional tool 8 shown in FIG. 1b is a planar shape, and the electric field formed by the tool 8 in the processing region 91 during the microelectrolysis process (the plurality of workpieces 9 are oriented toward the workpiece 9) The arrow of the tool 8 is particularly concentrated on the edge of the tool 8, resulting in a large current density of the edge relative to other parts, and the unevenness of the current density causes the appearance of the workpiece 9 to be uneven, even A discharge phenomenon is particularly likely to occur at the edge to impair the effect of microelectrolysis processing. Here, the processed portion 11 of the cutter 1 is formed into a spherical shape as shown in FIGS. 2a and 2b, or a convex aspherical shape similar to the spherical shape, as shown in FIG. 2a, the cutter 1 The electric field formed by the processing region 21 of the workpiece 2 (indicated by a plurality of arrows from the workpiece 2 toward the cutter 1) is evenly distributed, so that the current density of each part can be made uniform to avoid the finished workpiece 2 The above-mentioned undesirable phenomenon occurs in appearance. Moreover, the maximum diameter of the processed portion may be 0.01 to 1.0 mm, whereby the current density can be appropriately adjusted to ensure smooth progress of the micro-electrolysis process, and if the diameter is larger than 1.0 mm, the current density is lowered. In order to increase the current density, it is necessary to apply a high current, and the processing machine capable of performing micro-electrolysis processing is limited to a machine capable of outputting high energy, and the energy consumed is increased without economic efficiency. On the other hand, if the diameter is less than 0.01 In the case of mm, the processing region 21 is made too small to reduce the efficiency of microelectrolysis processing.

Further, the processing speed of the processing portion 11 of the tool 1 with respect to the workpiece 2 may be 10 to 40 μm/min, whereby microelectrolysis processing may be performed at an appropriate time, if the feed speed is greater than 40 μm/min. , the appearance of the workpiece 2 is not uniform, and if the feed speed is less than 10 μm/min, the surface erosion is too long due to the excessive residence time of the cutter 1 and cannot be applied to the Microelectrolysis processing of deionized water. In addition, the knife The tool 1 can set the feeding direction according to the appearance of the desired workpiece 2, for example, the processing portion 11 is held in the direction of the workpiece 2, and the depth of the pocket in which the tool 1 is machined can be deepened, or A predetermined path is set to the processing portion 11, such as an S-shaped path or a geometric pattern such as a square groove, and the corresponding appearance shape can be processed on the workpiece 2.

Further, the processing portion 11 of the tool 1 can be set to rotate during processing, and the rotational speed of the processing portion 11 can be 60 to 1000 rpm, whereby the electric field of the micro-electrolysis machining can be uniformly applied to the workpiece 2 to obtain a comparison. The uniform processing appearance, if the rotation speed is greater than 1000 rpm, causes vortex formation in the processing region 21, so that the sludge generated by the micro-electrolysis processing is retained in the processing region 21 and is not easily removed, thereby hindering the progress of the micro-electrolysis process, and the other On the other hand, if the number of revolutions is less than 60 rpm, the rate of renewal of the deionized water in the processing region 21 is too slow, and it is difficult to sufficiently remove the sludge, thereby hindering the progress of the microelectrolysis process.

In addition, in the deionized water micro-electrolysis processing method of the present invention, an additional abrasive grain may be added, and the workpiece 2 may be ground while performing deionized water micro-electrolysis processing, and the abrasive grain may be selected from general abrasive particles commonly used for grinding. The preparation may be made, for example, by selecting an alumina abrasive grain, a diamond abrasive grain, a cubic boron nitride abrasive grain or a carbonized cerium abrasive grain. The particle size of the abrasive grains may be 1.0 to 5.0 μm, whereby the grinding effect of the abrasive grains can be matched during microelectrolysis processing, and the processing amount for the workpiece 2 can be increased and the processing efficiency can be improved, if the particle diameter is greater than 5.0. In the case of μm, the abrasive grains block the conductive path of the deionized water, and it is difficult to cause microelectrolysis processing. On the other hand, if the particle diameter is less than 1.0 μm, the height of the abrasive grain deposition is insufficient, and the polishing effect cannot be sufficiently exhibited. Moreover, in the deionized water micro-electrolysis processing method of the present invention, in the case where the circulation tank is installed and the abrasive grains are added, an ultrasonic oscillator may be coupled to the circulation tank for oscillating the abrasive grains to avoid the The abrasive grains are deposited in the circulation tank and cannot flow to the processing region 21.

Moreover, since the abrasive grains are non-conducting, when the abrasive grains enter the electric field, the current density is insufficient to cause an abnormal retraction, and the tool 1 is reciprocally processed in the same portion, thereby causing the workpiece 2 to erode holes. As a result, the surface roughness is large. Therefore, the departure of the present invention The sub-water micro-electrolysis processing method is selected in the process design, and the abrasive particles can be selected according to the processing requirements of the workpiece 2. For example, when the workpiece 2 is to have a low surface roughness, the deionized water is not added with the abrasive particles. The electrolytic processing method is mainly used. When it is desired to increase the processing amount of the workpiece 2 or to increase the processing efficiency, the deionized water microelectrolysis processing method in which the abrasive grains are added is mainly used. Alternatively, the deionized water microelectrolysis processing method of the present invention in which the abrasive grains are added may be selected in a rough processing stage, and the deionized water microelectrolysis processing method of the present invention to which the abrasive grains are not added may be subjected to a fine processing stage to take into consideration The depth of the workpiece 2 and the integrity of the appearance.

The deionized water microelectrolysis processing method of the present invention can produce fine pits, and can make the pits have a flat appearance and a low surface roughness, which is sufficient for manufacturing a fine mold. In order to confirm that the deionized water microelectrolysis processing method of the present invention can be applied to fine mold processing, the following experiment is carried out: First, (a) the deionized water microelectrolysis processing method of the present invention without adding the abrasive grains and (b) The results of the drilling process of the deionized water microelectrolysis processing method of the present invention to which the abrasive grains are added, wherein the abrasive grains are alumina abrasive grains, and the alumina abrasive grains have a particle diameter of 3 μm. The bottom macroscopic morphology of the micro-pits produced by the methods is measured by a conjugate focal-focus laser interferometer, and the result of the (a) group is represented by a 3a graph, and the result of the (b) group is represented by a 3b graph. It can be seen that the 3b image has a relatively complete macroscopic morphology compared to the 3a image, and the processing depth can reach 20 μm or more. Therefore, it can be confirmed that the addition of the alumina abrasive grains can increase the grinding effect. However, the microscopic images of the micro-pits produced by these methods were observed by scanning electron microscopy (SEM), and the observation results were shown in Fig. 4a and Fig. 4b, respectively. It can be seen that the 4b map is compared with the 4a map. The pitting phenomenon occurs more obviously, resulting in a larger surface roughness. Among them, the surface roughness of Fig. 4a is 0.169 μm, and the surface roughness of Fig. 4b is 1.085 μm.

Deionized water micro-electrolysis machining milling deep groove experiment: set the voltage to 50V, the current is 50mA pulse DC current, the pulse DC current pulse width is 0.2μs, the pulse breaking time is 0.8μs, the deionized water ratio The resistance value was 110 kΩ-cm, the spherical diameter of the processed portion 11 was 0.35 mm, the rotational speed of the processed portion 11 was 500 rpm, the feed speed of the processed portion 11 was 30 μm/min, and the deep groove processing area was 0.2 × 0.1 mm ^{2 .} And the deep groove is divided into 10 layers of processing, each layer is 0.01mm. The processing results are as shown in Fig. 5a, Fig. 5b and Fig. 5c, wherein the processing depth is about 0.12 mm, the aspect ratio of the deep groove is 1.2 times, and the surface roughness Ra is 0.227 μm. The deionized water micro-electrolysis processing method of the invention can obtain a good surface topography and a low surface roughness, and can achieve a depth of 0.12 mm or more if a layered processing of an appropriate number of layers is set during processing.

Deionized water micro-electrolysis machining milling micro-channel experiment: set the voltage to 50V, the current is 50mA pulse DC current, the pulse DC current pulse width is 0.2μs, the pulse breaking time is 0.8μs, the deionized water The specific resistance value is 110 kΩ-cm, the spherical diameter of the processed portion 11 is 0.35 mm, the rotational speed of the processed portion 11 is 500 rpm, and the feed speed of the processed portion 11 is 30 μm/min, and the microchannel is S-type, wherein The radius of the curved portion is set to (a) 0.5 mm and (b) 1.0 mm, and the micro flow path is divided into two layers, each layer being 0.01 mm. The processing result of the group (a) is as shown in Fig. 6a, wherein the surface roughness Ra of the S-type microchannel is about 0.36 μm, and the processing result of the group (b) is as shown in Fig. 6b, wherein The surface roughness Ra of the S-type microchannel is about 0.36 μm, and it can be known that the micro-scale processing of the processing portion 11 can be appropriately set by the deionized water micro-electrolysis processing method of the present invention. The micro flow channel.

Deionized water micro-electrolysis machining milling square groove experiment: set the voltage to 50V, the current is 50mA pulse DC current, the pulse DC current pulse width is 0.2μs, the pulse breaking time is 0.8μs, the deionized water ratio The resistance value is 110 kΩ-cm, the spherical diameter of the processed portion 11 is 0.35 mm, the rotational speed of the processed portion 11 is 500 rpm, the feed speed of the processed portion 11 is 30 μm/min, and the square groove processing area is 0.6 × 0.6 mm ² And the square groove is divided into two layers of processing, each layer is 0.01mm. The processing results are as shown in Fig. 7a and Fig. 7b, wherein the processing depth is about 50 μm and the surface roughness Ra is 1.8 to 2.0 μm. It can be known that the deionized water microelectrolysis processing method of the present invention is suitable for processing. By setting the feed path of the processed portion 11, it is possible to produce a bottom non-spherical recess such as a square groove, and it is possible to achieve a depth of 50 μm by setting two layers of processing during processing.

In summary, the present invention can reduce the possibility of occurrence of a discharge phenomenon in the deionized water micro-electrolysis process by appropriately setting the voltage and current density, so that the bottom of the workpiece 2 is reduced in pitting corrosion caused by the discharge phenomenon. The milled surface of the pit having a small surface roughness and a flat appearance or an arbitrary path is obtained. Therefore, the deionized water microelectrolysis processing method of the present invention can be applied to the manufacture of a micro mold.

In addition, the energy required for the deionized water microelectrolysis processing method of the present invention can be supplied by a general electric discharge machine, and the microelectrolysis process can be achieved by reducing the discharge phenomenon by appropriately setting the voltage and current density, thereby saving the purchase of electrolysis. The cost of processing machines increases economic efficiency.

While the present invention has been disclosed in the above embodiments, it is not intended to limit the scope of the present invention. The scope of protection of the invention is therefore defined by the scope of the appended claims.

Claims (10)

A method for micro-electrolysis of deionized water, comprising: using a workpiece as an anode and a tool as a cathode, the tool having a processing portion facing the workpiece; and flowing in deionized water Under the voltage of 20~50V and the current density of 25~200A/cm ² , the tool is subjected to micro-electrolysis processing of the workpiece by the processing part, wherein the specific de-ionized water has a specific resistance value of 20~120kΩ-cm. . The method for microelectrolysis of deionized water according to claim 1, wherein the processed portion has a spherical shape or a convex aspherical shape similar to a sphere. The method for micro-electrolysis of deionized water according to claim 3, wherein the processed portion has a maximum diameter of 0.01 to 1.0 mm. The method for microelectrolysis of deionized water according to claim 1, wherein the processing portion of the tool performs microelectrolysis processing at a number of revolutions of 60 to 1000 rpm. The method for micro-electrolysis of deionized water according to claim 1, wherein the processing portion of the tool performs micro-electrolysis machining drilling or milling at a feed rate of 10 to 40 μm/min with respect to the workpiece. . The deionized water microelectrolysis machining method according to claim 1, wherein a current of 50 to 100 mA is applied to the workpiece and the cutter so that the current density reaches 25 to 200 A/cm ² . The method for micro-electrolysis of deionized water according to claim 7, wherein the current is a pulsed direct current having a pulse width of 0.1 to 0.5 μs. The deionized water microelectrolysis processing method according to claim 1, wherein the flowing deionized water comprises an abrasive grain. The method for micro-electrolysis of deionized water according to claim 9, wherein the abrasive particles are an alumina abrasive grain, a diamond abrasive grain, a cubic boron nitride abrasive grain or a carbonized honing machine. grain. The method for microelectrolysis of deionized water according to claim 10, wherein the abrasive grains have a particle diameter of 1.0 to 5.0 μm.