JP2015094007A - Manufacturing method of casing, and film forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique to form, in the same process, a corrosion-resistant film having different film thicknesses according to parts of a casing, when coating a base material surface using magnesium alloy with the corrosion-resistant film.SOLUTION: A manufacturing method of a casing whose base material surface using magnesium alloy is coated with a corrosion-resistant film includes: a film treatment step of immersing the casing in a first treatment liquid for forming the corrosion-resistant film on the base material surface, and forming the corrosion-resistant film on the base material surface; and a surface adjustment treatment step which is performed before the film treatment step, of immersing the casing in a second treatment liquid for suppressing a reaction of the first treatment liquid and the base material surface during the film treatment step, and forming a surface adjustment film on the base material surface. In the surface adjustment treatment step, air bubbles generated and adhered by a reaction with the second treatment liquid are removed from a predetermined thin-film forming part of the base material surface, in which a film thickness of the corrosion-resistant film is to be made thinner than the other parts.

Description

  The present invention relates to a housing manufacturing method and a film forming apparatus.

  Magnesium alloys are attracting attention as housing materials for notebook computers and mobile phones. Since the magnesium alloy has a high specific strength and a low specific gravity, the casing can be made lighter and stronger than conventional resin casings and aluminum casings.

  However, since the magnesium alloy has low corrosion resistance compared to other metal materials and resin materials, it is necessary to form a corrosion-resistant film having high corrosion resistance such as chemical conversion treatment on the surface of the casing. Here, when the corrosion-resistant film is a thick film, although it is excellent in coating adhesion, conductivity (grounding property) tends to be poor. Further, the resistance value of the corrosion-resistant film varies depending on the film thickness. Therefore, when the corrosion-resistant film is a thin film, the coating adhesion is likely to be poor, although the conductivity of the film can be ensured.

  However, the performance required for the housing may differ depending on the part. For example, the outer surface exposed to the outside of the housing surface requires paint adhesion in addition to excellent corrosion resistance, but the demand for conductivity is often not so high. On the other hand, the inner surface of the housing surface that is not exposed to the outside is not required to have paint adhesion as much as the outer surface, but is often required to be conductive in order to ensure the grounding property of the housing.

JP 2007-277690 A

  However, conventionally, when forming a corrosion-resistant film on the surface of the housing, it was impossible to simultaneously form a corrosion-resistant film having a different thickness for each part. This case has been made in view of the above-mentioned problems, and its purpose is to provide a corrosion-resistant film having a different film thickness depending on the part of the housing when the substrate surface using the magnesium alloy is coated with the corrosion-resistant film. It is to provide a technique for forming in the same process.

  According to one aspect of the present invention, there is provided a method for manufacturing a housing in which a base material surface using a magnesium alloy is coated with a corrosion-resistant film, the first treatment liquid for forming the corrosion-resistant film on the substrate surface. A film treatment step for immersing the casing to form the corrosion-resistant film on the surface of the base material, and before the film treatment step, the first treatment liquid and the surface of the base material in the film treatment step. A surface adjustment treatment step of immersing the casing in a second treatment liquid for suppressing the reaction of the substrate to form a surface adjustment film on the surface of the substrate. In the surface adjustment treatment step, the surface of the substrate A method for manufacturing a housing is provided, in which bubbles generated and adhered to a predetermined thin film formation site where the thickness of the corrosion-resistant film is made thinner than other sites are removed by reaction with the second treatment liquid. .

According to another aspect of the present invention, there is provided a film forming apparatus that forms a corrosion-resistant film on the surface of a base material of a housing using a magnesium alloy, and is a first device for forming the corrosion-resistant film on the surface of the base material. In order to suppress the reaction between the first treatment liquid and the substrate surface in the corrosion-resistant film treatment unit that forms the corrosion-resistant film on the substrate surface by immersing the casing in the treatment solution. A surface adjustment treatment tank for storing the second treatment liquid, and a surface adjustment treatment section for immersing the casing in the second treatment liquid in the surface adjustment treatment tank to form a surface adjustment film on the substrate surface And the surface conditioning treatment part is generated by reaction with the second treatment liquid at a predetermined thin film forming part that makes the film thickness of the corrosion-resistant film thinner than other parts of the substrate surface. Bubble removal device to remove attached bubbles And further comprising film forming apparatus is provided.

  According to this case, when the base material surface using a magnesium alloy is coated with a corrosion-resistant film, it is possible to provide a technique for forming a corrosion-resistant film having a different film thickness in the same process according to the part of the casing. .

FIG. 3 is a diagram illustrating a housing according to the first embodiment. It is a figure which shows the film formation apparatus which forms a chemical conversion film on the surface of a housing | casing. It is a figure which illustrates the procedure of a surface adjustment process notionally. It is a figure which shows a rack. It is a figure which shows an injection unit. It is a figure which shows the state which assembled | attached the injection unit to the rack. It is a figure which shows the state which immersed the housing | casing in the surface adjustment process liquid. In a surface adjustment process, it is a figure which shows notionally the state before injecting a surface adjustment process liquid from an injection nozzle. In a surface adjustment process, it is a figure which shows notionally the state which is injecting the surface adjustment process liquid from an injection nozzle. It is a figure which shows the conductivity evaluation result of an Example and a comparative example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the invention will be exemplarily described in detail with reference to the drawings.

<Embodiment 1>

  FIG. 1 is a diagram illustrating a housing 1 according to the first embodiment. A front view of the housing 1 is shown in the lower stage, and a cross section taken along the line AA of the housing 1 is shown in the upper stage. The housing 1 is a housing of an electronic device such as a notebook personal computer or a mobile phone. The base material 11 of the housing 1 is made of a magnesium alloy, and the surface of the base material 11 is covered with a chemical conversion film 12. Further, a surface conditioning film 13 is interposed between the surface of the substrate 11 and the chemical conversion film 12. The base material 11 may be manufactured, for example, by pressing a flat plate made of a magnesium alloy using a press die. However, the manufacturing method of the base material 11 is not limited to press work.

Reference numerals 11a and 11b shown in FIG. 1 indicate an outer surface (front surface) and an inner surface (back surface) of the base material 11, respectively. The outer surface 11a of the base material 11 is an outer surface exposed to the outside in a state where the outer surface 11a of the base 1 is assembled as a finished product. On the other hand, the inner surface 11b of the base material 11 is an inner surface that is not exposed to the outside in a state of being assembled as a finished product among the surfaces of the housing 1, and is, for example, a surface facing the housing portion that houses the components of the electronic device. doing. As shown in FIG. 1, the surface adjustment film 13 covering the base material 11 of the housing 1 has a relatively thin outer surface 11a compared to the inner surface 11b. And among the chemical conversion film 12 laminated | stacked on the surface adjustment film | membrane 13 which coat | covers the surface of the base material 11, the chemical conversion film 12 which coat | covers the outer surface 11a side is formed as a thick film, and the chemical conversion film 12 which coat | covers the inner surface 11b side is It is formed as a thin film. That is, the inner surface 11 b is relatively thinner than the outer surface 11 a of the base material 11.

  FIG. 2 is a view showing a film forming apparatus 10 that forms a chemical conversion film 12 on the surface of the base material 11 in the housing 1. The film forming apparatus 10 includes a surface adjustment processing unit 2 and a chemical conversion film processing unit 3. The chemical film treatment unit 3 performs chemical film treatment for forming a chemical film 12 on the surface of the base material 11 in the housing 1. Specifically, the chemical conversion film treatment unit 3 includes a chemical conversion treatment tank 30 in which a chemical conversion film treatment liquid 31 is stored, and the case 1 is immersed in the chemical conversion film treatment liquid 31 so that the corrosion resistant film is formed on the surface of the substrate 11. The chemical conversion film 12 is formed. The chemical film treatment liquid 31 is an example of a first treatment liquid. The chemical conversion film treatment liquid 31 contains, for example, a fluorine compound. However, as the chemical film treatment liquid 31, various known chemical conversion liquids for magnesium alloys can be used.

  In the chemical conversion film processing unit 3 of the film forming apparatus 10, the chemical conversion films 12 having different film thicknesses are formed at the same time, that is, in the same process, according to the site of the housing 1. Specifically, the front surface 11a of the housing 1 forms a chemical conversion film 12 as a thick film in order to obtain excellent coating adhesion in addition to corrosion resistance. Further, on the inner surface 11b of the housing 1, a chemical conversion film 12 is formed as a thin film in order to ensure conductivity in addition to corrosion resistance.

  By the way, when the housing 1 is simply immersed in the chemical film treatment liquid 31, the chemical coating 12 having a uniform thickness is formed on the surface of the housing 1. In this case, in the same process, the chemical conversion film 12 cannot be formed on the outer surface 11a as a thick film, and the chemical conversion film 12 cannot be formed on the inner surface 11b as a thin film. Therefore, in the film forming apparatus 10, prior to the chemical conversion film treatment in the chemical conversion film processing unit 3, the surface adjustment processing for adjusting the surface of the base material 11 in the surface adjustment processing unit 2 is performed in the surface adjustment processing step. .

  As shown in FIG. 2, the surface adjustment processing unit 2 has a surface adjustment treatment tank 20, and a surface adjustment treatment liquid 21 is stored in the surface adjustment treatment tank 20. In the surface adjustment processing unit 2, the housing 1 reacts with the surface adjustment processing liquid 21 by being immersed in the surface adjustment processing liquid 21 of the surface adjustment processing tank 20, and the surface adjustment coating 13 is formed on the surface of the substrate 11. Form. For example, a polyoxyethylene laurate-like substance can be suitably used as the surfactant component contained in the surface conditioning treatment liquid 21. When the surface conditioning film 13 is formed on the surface of the housing 1 by the surface conditioning treatment liquid 21 containing a surface active component, the chemical conversion film treatment liquid 31 and the surface of the substrate 11 in the subsequent chemical film treatment process are used. The reaction is suppressed (reduced). As a result, the thicker the surface adjustment film 13 that covers the surface of the substrate 11 in the casing 1 is, the thinner the chemical conversion film 12 is formed during the chemical conversion film treatment, and the thinner the surface adjustment film 13 is, the chemical conversion film treatment is performed. Sometimes the thickness of the chemical conversion film 12 formed becomes thick. Therefore, in the surface adjustment processing step in the surface adjustment processing unit 2, the surface adjustment film 13 having different thicknesses is formed on the outer surface 11a side and the inner surface 11b side of the base material 11 of the housing 1. Specifically, the surface adjustment processing unit 2 adjusts the film thickness of the surface adjustment film 13 formed on the inner surface 11b of the housing 1 so as to be relatively thick compared to the outer surface 11a side. To implement.

FIG. 3 is a diagram for conceptually explaining the procedure of the surface adjustment processing. In addition, in FIG. 3, the external shape of the housing | casing 1 is simplified and shown. When the housing 1 is immersed in the surface conditioning treatment liquid 21 stored in the surface conditioning treatment tank 20, the magnesium alloy forming the base material 11 in the housing 1 reacts with the surface conditioning treatment liquid 21, whereby the base material 11. Bubbles 22 are generated and adhered to the surface of If the bubbles 22 are left on the surface of the base material 11, the reaction between the magnesium alloy forming the surface of the base material 11 and the surface conditioning treatment liquid 21 is suppressed (slows down). Therefore, in the present embodiment, among the surface of the base material 11 in the housing 1, the chemical film 12 is generated and attached to the inner surface 11 b (thin film forming portion) that makes the film thickness of the chemical conversion film 12 thinner than the outer surface 11 a (other portions). The surface adjustment process is performed while removing the air bubbles 22. Here, the removal of the bubbles 22 attached to the inner surface 11b of the housing 1 may be performed continuously or intermittently (intermittently).

  By performing the surface adjustment process while removing the bubbles 22 attached to the inner surface 11b of the housing 1, the reaction between the inner surface 11b and the surface adjustment treatment liquid 21 is actively performed, and the growth of the surface adjustment film 13 is promoted. Is done. On the other hand, regarding the outer surface 11a where the bubbles 22 are not removed during the surface adjustment process, the thickness of the surface adjustment film 13 formed as a film is thinner than that of the inner surface 11b. Thus, in the surface adjustment process according to the present embodiment, the inner surface 11b side of the surface adjustment film 13 formed on the surface of the base material 11 in the housing 1 can be made thicker than the outer surface 11a side. Hereinafter, specific contents of the surface adjustment processing unit 2 for realizing such surface adjustment processing will be described. In this embodiment, an example in which the chemical conversion film 12 having different thicknesses is formed on the outer surface 11a and the inner surface 11b of the housing 1 will be described. The portion to be thinned can be set freely.

  Details of the surface adjustment processing unit 2 will be described with reference to FIGS. 2, 4, and 5. The surface adjustment processing unit 2 includes a rack 4, an injection unit 5 and the like in addition to the surface adjustment processing tank 20 in which the surface adjustment processing liquid 21 is stored. When performing the surface adjustment treatment, the housing 1 is immersed in the surface adjustment treatment liquid 21 while being held (fixed) in the rack 4 (see FIG. 2).

  FIG. 4 is a view showing a rack (jig) 4. The rack 4 includes a pair of holding portions 41 and a pair of holding portions 42 that sandwich a pair of opposing edge portions of the housing 1. FIG. 4 shows only one of the pair of holding portions 41 and the pair of holding portions 42. The holding portions 41 and 42 have a waveform or a continuous V shape, and can support the plurality of cases 1 in parallel with each other at a predetermined interval. Hereinafter, the posture of the housing 1 illustrated in FIG. 4 is defined as the vertical posture of the housing 1. In the example shown in FIG. 4, the rack 4 has three housings held (fixed) by the holding portions 41 and 42 in a vertical posture at regular intervals.

  FIG. 5 is a diagram showing the injection unit 5. The injection unit 5 includes a plurality of injection nozzles 50, a supply pipe 51 connected to each injection nozzle 50, a pump 52, a frame body 53, a partition cover 54, and the like. The frame body 53 is a skeleton member including a vertical frame 531 and a horizontal frame 532 assembled in a three-dimensional lattice pattern, and the injection nozzle 50 partition cover 54 and the like are fixed thereto.

  One end side of the supply pipe 51 is connected to the pump 52. The supply pipe 51 branches from a distribution unit 510 provided in the middle thereof into a plurality of branch pipes 511. As shown in FIG. 5, the branch pipe 511 of the supply pipe 51 is disposed along the vertical frame 531 in the frame body 53, and is fixed to the vertical frame 531 at an appropriate position. The number of vertical frames 531 in the frame body 53 is the same as the number of the branch pipes 511. In this embodiment, the frame body 53 includes nine vertical frames 531 in a 3 × 3 arrangement.

  A plurality of injection nozzles 50 are connected to each branch pipe 511 arranged along the vertical frame 531 at predetermined intervals. The spray nozzle 50 is fixed to the vertical frame 531 via an attachment 55. In the example shown in FIG. 5, five injection nozzles 50 are attached to each branch pipe 511 at substantially constant intervals. In the injection unit 5 formed in this way, the surface adjustment treatment liquid 21 is pumped by the operation of the pump 52, and the surface adjustment treatment liquid 21 is supplied to each injection nozzle 50 through the supply pipe 51. Yes. The surface conditioning treatment liquid 21 supplied to each spray nozzle 50 is sprayed in a predetermined direction from the spray nozzle of each spray nozzle 50.

As shown in FIG. 5, each injection nozzle 50 is attached to the vertical frame 531 of the frame body 53 in such a posture that the injection port faces obliquely downward. More specifically, the angle formed between the spray direction in which the surface conditioning liquid 21 is sprayed from the spray nozzle of each spray nozzle 50 and the longitudinal axis direction of the vertical frame 531 is adjusted in the range of 5 to 20 °. Further, the partition cover 54 shown in FIG. 5 is a partition member having a flat plate shape. The partition cover 54 is fixed to the vertical frame 531 in the frame body 53 and is disposed along the vertical frame 531. The function of the partition cover 54 will be described later.

  Next, the detail of the surface adjustment process implemented in the surface adjustment process part 2 is demonstrated. When performing the surface adjustment process, first, the housing 1 is fixed to the rack 4, and then the injection unit 5 is assembled to the rack 4 (see FIGS. 4 and 6). As shown in FIG. 6, in the state where the injection unit 5 is assembled to the rack 4, the injection ports of the injection nozzles 50 face the back surface 11 b of the base material 11 in the housing 1.

  Next, the rack 4 in which the casing 1 is held and the injection unit 5 is assembled is installed in the surface adjustment treatment tank 20 in which the surface adjustment treatment liquid 21 is stored up to a predetermined liquid level, as shown in FIG. The housing 1 is immersed in the surface adjustment treatment liquid 21 as described above. The procedure of each process up to the state shown in FIG. For example, the surface adjustment treatment liquid 21 may be stored in the surface adjustment treatment tank 20 after the rack 4 and the injection unit 5 that hold the casing 1 are installed in the surface adjustment treatment tank 20. Further, after the rack 4 is installed in the surface conditioning treatment tank 20, the injection unit 5 may be assembled to the rack 4.

  In the surface adjustment process, the housing 1 immersed in the surface adjustment treatment liquid 21 reacts with the surface of the base material 11 and the surface adjustment treatment liquid 21, and the surface adjustment film 13 is gradually formed. Then, in the progress of the surface conditioning process, the magnesium alloy forming the base material 11 of the housing 1 and the surface conditioning liquid 21 react to generate bubbles 22, and the bubbles 22 adhere to the surface of the base material 11. To do. FIG. 8 is a diagram conceptually showing a state before the surface adjustment processing liquid 21 is ejected from the ejection nozzle 50 in the surface adjustment processing for the housing 1. FIG. 9 is a diagram conceptually illustrating a state in which the surface adjustment treatment liquid 21 is being ejected from the ejection nozzle 50 in the surface adjustment process for the housing 1.

  As shown in FIG. 8, before the surface adjustment treatment liquid 21 is ejected from the ejection nozzle 50, the air bubbles 22 are similarly attached to the outer surface 11 a and the inner surface 11 b of the substrate 11. On the other hand, in the present embodiment, the surface conditioning treatment liquid 21 is sprayed from the spray nozzle 50 onto the inner surface 11b that forms the chemical coating 12 as a thin film during the subsequent chemical coating treatment. The liquid flow is caused to collide with the bubbles 22 attached to the inner surface 11b. As a result, as shown in FIG. 9, the bubbles 22 attached to the inner surface 11 b of the base 11 in the housing 1 can be washed away and removed. As a result, on the inner surface 11b of the base material 11, the reaction between the magnesium alloy and the surface conditioning treatment liquid 21 is not inhibited and promoted. Thereby, the surface adjustment film | membrane 13 can be uniformly formed in the inner surface 11b of the base material 11 in the housing | casing 1. FIG.

On the other hand, on the outer surface 11a of the base material 11 in the housing 1, the bubbles 22 are not removed during the surface adjustment process and remain attached. As a result, the surface adjustment film 13 is hardly formed on the outer surface 11a, or the surface adjustment film 13 formed on the outer surface 11a is significantly thinner than the film thickness of the surface adjustment film 13 formed on the inner surface 11b (FIG. 1). See). In the surface adjustment process in the present embodiment, the surface adjustment treatment liquid 21 may be ejected from the ejection nozzle 50 in a timely manner. For example, the ejection timing of the surface adjustment treatment liquid 21 from the ejection nozzle 50 may be determined according to the degree of adhesion of the bubbles 22 on the inner surface 11 b of the base material 11. And whenever the injection timing determined in this way comes, the chemical | medical solution may be intermittently injected by injecting the surface adjustment process liquid 21 from the injection nozzle 50 over predetermined time. Further, the surface conditioning treatment liquid 21 ejected from each ejection nozzle 50 in the ejection unit 5 is pumped by sucking the surface conditioning treatment liquid 21 stored in the surface conditioning treatment tank 20 by a pump 52, and supplied to a supply pipe 51.
You may supply to the injection nozzle 50 via this.

  Here, when the surface adjustment processing in the surface adjustment processing unit 2 is completed, the rack 4 is pulled up from the surface adjustment processing tank 20 and the injection unit 5 is removed from the rack 4. Here, the housing 1 after the surface adjustment process is maintained in a state of being held by the rack 4. Next, after the casing 1 held on the rack 4 is washed with water, a chemical conversion film treatment is performed on the casing 1 in the chemical conversion film processing unit 3 at the subsequent stage. As shown in FIG. 2, the chemical conversion film treatment unit 3 has a chemical conversion treatment tank 30 that stores a chemical conversion film treatment liquid 31, and the casing 1 is immersed in the chemical conversion film treatment liquid 31 to provide corrosion resistance to the surface of the substrate 11. The chemical conversion film 12 which is a film is formed.

  In this embodiment, since the housing 1 is subjected to a surface adjustment process prior to the chemical conversion film treatment, the surface adjustment film 13 is uniformly formed on the inner surface 11 b of the base material 11. Therefore, when the chemical film treatment in the chemical film treatment unit 3 is performed, the reaction between the magnesium alloy and the chemical film treatment liquid 31 is suppressed on the inner surface 11 b of the base material 11. On the other hand, the outer surface 11a of the substrate 11 is not uniformly coated with the surface adjustment film 13, and the surface adjustment film 13 formed on the outer surface 11a is significantly thinner than the inner surface 11b side. Therefore, on the outer surface 11a side of the base material 11, the reaction between the magnesium alloy and the chemical conversion film treatment liquid 31 is not inhibited, and the film formation of the chemical conversion film 12 is promoted.

  As described above, in the method for manufacturing the housing 1 according to the present embodiment, the reaction with the surface adjustment treatment liquid 21 is performed on the inner surface 11b of the surface of the base material 11 where the film thickness of the chemical conversion film 12 is made thinner than the outer surface 11a. The surface adjustment treatment was performed while removing the generated and attached bubbles 22. Thereby, the film thickness of the chemical conversion film 12 can be changed according to a site | part in the same process. And since the chemical conversion film 12 formed in the outer surface 11a exposed outside when the housing | casing 1 is assembled can be made into a thick film, in addition to corrosion resistance, it provides the coating | coated adhesion excellent in the outer surface 11a. Can do. Moreover, since the chemical conversion film 12 formed on the inner surface 11b that is not exposed to the outside when the housing 1 is assembled can be formed into a thin film, excellent conductivity in addition to corrosion resistance can be imparted to the inner surface 11b. .

  And in this embodiment, according to the site | part of the housing | casing 1, the chemical conversion film 12 from which a film thickness differs can be formed in the same process (at the same time). According to this, the entire surface of the housing is covered with a thick chemical conversion film, and a part of the surface is peeled off by a laser or the like in a later process, and a conductive tape is applied, a screw is tightened, etc. This is advantageous in the following points as compared with the conventional method in which the contact portion is made conductive. That is, compared with the said conventional method, a man-hour can be reduced and the manufacturing cost of a housing | casing can be reduced. Moreover, according to the manufacturing method of the housing in the present embodiment, it is not necessary to peel a part of the chemical conversion film, and the risk of the future corrosion of the housing using the magnesium alloy as the base material is further reduced. Can do.

  Furthermore, the surface adjustment processing unit 2 immerses the casing 1 in the surface adjustment processing liquid 21 of the surface adjustment processing tank 20 and directs the spray nozzle 50 disposed in the surface adjustment processing tank 20 toward the inner surface 11 b of the base material 11. Spray. And the bubble 22 adhering to the inner surface 11b was removed by the liquid flow of the surface adjustment treatment liquid 21 ejected from the ejection nozzle 50. Thereby, the bubble 22 adhering to the inner surface 11b of the housing | casing 1 can be removed smoothly. Moreover, since the fresh surface adjustment processing liquid 21 can be supplied to the inner surface 11b of the housing 1, it is possible to promote the formation of a uniform surface adjustment film 13 on the inner surface 11b. Moreover, since the processing liquid used for the surface adjustment processing of the base material 11 is used for the purpose of removing the bubbles 22, the concentration of the surface adjustment processing liquid 21 in the surface adjustment processing tank 20 changes, or the surface adjustment processing. Mixing of the liquid 21 with other liquids can be avoided.

In this embodiment, the outer surface 11a of the base material 11 is an example of a thick film forming part, and the inner surface 11b
Is an example of a thin film formation site. Moreover, the chemical conversion film treatment liquid 31 and the surface adjustment treatment liquid 21 are examples of the first treatment liquid and the second treatment liquid, respectively. Moreover, in this embodiment, the chemical conversion film process part 3 is an example of a corrosion-resistant film process part, and the injection unit 5 is an example of a bubble removal apparatus.

  In addition, as described above, the angle formed between the spray direction in which the surface adjustment treatment liquid 21 is sprayed from the spray nozzle of each spray nozzle 50 in the spray unit 5 and the longitudinal axis direction of the vertical frame 531 is in the range of 5 to 20 °. It has been adjusted. Then, the angle at which the liquid flow of the surface adjustment treatment liquid 21 ejected from the ejection nozzle 50 is incident on the inner surface 11b of the casing 1 fixed in a vertical posture to the rack 4 (hereinafter referred to as “liquid flow incident angle”). Θ) is approximately 5 to 20 °. Thus, by setting the liquid flow incident angle θ to a gentle angle, the liquid flow ejected from the ejection nozzle 50 can be propelled along the inner surface 11b so as to stroke the inner surface 11b of the housing 1. The bubbles 22 attached to 11b can be efficiently removed. Further, as described above, by reducing the liquid flow incident angle θ, the liquid flow after colliding with the inner surface 11b of the casing 1 can be made difficult to collide with the outer surface 11a of the adjacent casing 1. As a result, it is possible to suppress the removal of the bubbles 22 attached to the outer surface 11a of the housing 1 during the surface adjustment process. Therefore, the formation of the chemical conversion film 12 on the outer surface 11a of the housing 1 can be promoted during the chemical conversion film treatment in the subsequent step, and the film thickness of the chemical conversion film 12 formed on the outer surface 11a can be sufficiently ensured. .

  Moreover, the injection unit 5 according to the present embodiment includes the partition cover 54 disposed along the vertical frame 531 of the frame body 53 as described with reference to FIG. The partition cover 54 extends along the plane of the housing 1 held by the rack 4 and separates the housings 1 from each other (see FIG. 7). According to this, after the surface adjustment treatment liquid 21 for removing the bubbles 22 attached to the inner surface 11b of the housing 1 is ejected from the ejection nozzle 50 during the surface adjustment processing, after colliding with the inner surface 11b of the housing 1 It is possible to suitably prevent the liquid flow from colliding with the outer surface 11a of the adjacent casing 1. As a result, it is possible to suppress the removal of the bubbles 22 attached to the outer surface 11a of the housing 1 during the surface adjustment process. Therefore, the formation of the chemical conversion film 12 on the outer surface 11a of the housing 1 can be promoted during the chemical conversion film treatment in the subsequent step, and the film thickness of the chemical conversion film 12 formed on the outer surface 11a can be sufficiently ensured. . Further, the injection unit 5 according to the present embodiment has a structure that is detachable from the rack 4. According to this, after the surface adjustment process in the surface adjustment processing unit 2 is completed, the chemical conversion film process is started when the rack 4 from which the injection unit 5 has been removed is put into the chemical conversion treatment tank 30 of the chemical conversion film processing unit 3 as it is. Because it is possible, it is highly convenient.

  In addition, in implementation of the surface adjustment process in the surface adjustment process part 2, the surface injected from the injection nozzle 50 according to the arrangement position of each injection nozzle 50 arrange | positioned in the surface adjustment processing tank 20 (surface adjustment process liquid 21). The injection pressure of the adjustment processing liquid 21 may be changed. Specifically, in the depth direction of the surface adjustment treatment tank 20, the injection nozzle 50 disposed at a shallow position (a position far from the bottom) as compared to the injection nozzle 50 disposed at a deep position (a position close to the bottom). The injection pressure may be relatively increased. As described above, each jet nozzle 50 in the jet unit 5 sets the liquid flow incident angle θ to a relatively small angle, causes the liquid flow to collide with the inner surface 11b of the housing 1 from a gentle angle, and the bubbles 22 Is removed along the inner surface 11b. Therefore, among the spray nozzles 50 arranged at regular intervals along the vertical frame 531 in the frame body 53, the liquid flow sprayed from the spray nozzle 50 is increased as the distance from the bottom of the surface adjustment treatment tank 20 is farther. The distance that the bubble 22 is washed away becomes longer. Therefore, by adjusting the spray pressure of the spray nozzle 50 as described above according to the depth of the spray nozzle 50 disposed in the surface adjustment treatment tank 20, the spray nozzle disposed at a shallow position of the surface adjustment treatment tank 20. It can be suppressed that the strength of the liquid flow ejected from 50 is insufficient. As a result, when the surface adjustment process is performed, the bubbles 22 attached to the inner surface 11b of the housing 1 can be suitably removed regardless of the arrangement position of each injection nozzle 50.

  The embodiment described above can be variously modified without departing from the gist of the present invention. Moreover, the above-mentioned embodiment and modification can be implemented combining them as much as possible.

<Example>
Next, examples will be described. In the examples, the surface conditioning treatment and the chemical conversion coating treatment described in the above embodiment were performed on a test piece (25 × 50 mm) of a magnesium alloy LZ91 (9% lithium, 1% zinc). At that time, a thick chemical conversion film was formed on one surface (hereinafter, front surface) of the test piece according to the example, and a thin film was formed on the other surface (hereinafter, back surface). In addition, as a comparative example, the same test piece as in the example was not subjected to surface conditioning treatment, and a thick chemical film was formed on both surfaces in the chemical film treatment. The test pieces according to Examples and Comparative Examples after the chemical conversion film treatment were washed with water, dried, and coated, and then the physical properties (resistance value, coating adhesion) regarding each test piece were compared.

FIG. 10 is a diagram showing the results of continuity evaluation of Examples and Comparative Examples. In addition, the notation “OL” in FIG. 10 means “over road” and indicates that the resistance value cannot be measured due to the over range. As shown in FIG. 10, in the test piece according to the example, the resistance value of the back surface on which the thin film was formed was significantly smaller than the front surface on which the chemical conversion film was formed as a thick film, and the back surface conduction was It was confirmed that the properties were excellent. As for coating adhesion, when a cross-cut test was performed on the front surface and the back surface of the test piece according to the example, both the front surface formed with a thick film and the back surface formed with a thin film There was no peeling of the paint. In addition, after performing a temperature and humidity cycle test on the test piece according to the example, and performing a cross cut test, the coating on the back surface formed as a thin film was peeled off, but the front surface formed as a thick film No peeling of the paint was observed. Therefore, it has confirmed that the coating adhesion of the front surface which formed the chemical conversion film as a thick film among the test pieces which concern on an Example was excellent. From the above, it was confirmed that different physical properties were imparted to the front surface and the back surface of the test piece according to the example.

DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Surface adjustment process part 3 ... Chemical conversion film process part 4 ... Rack 5 ... Injection unit 10 ... Film formation apparatus 11 ... Base material 11a ... Outer surface 11b ... Inner surface 12 ... Chemical conversion coating 13 ... Surface adjustment coating 20 ... Surface adjustment treatment tank 21 ... Surface adjustment treatment liquid 22 ... Bubble 30 ... Chemical conversion treatment bath 31 ...・ Chemical conversion film treatment liquid 50... Injection nozzle 51 .. supply pipe 52... Pump 53.

Claims (6)

A method for manufacturing a housing in which a substrate surface using a magnesium alloy is coated with a corrosion-resistant film,
A film treatment step of immersing the housing in a first treatment liquid for forming the corrosion-resistant film on the substrate surface to form the corrosion-resistant film on the substrate surface;
The substrate surface is immersed in a second treatment solution for suppressing the reaction between the first treatment solution and the substrate surface during the coating treatment step, which is performed before the coating treatment step. A surface conditioning process for forming a surface conditioning film on the surface;
Including
In the surface adjustment treatment step, bubbles generated and adhered by reaction with the second treatment liquid are removed from a predetermined thin film forming portion that makes the film thickness of the corrosion-resistant film thinner than other portions of the substrate surface. To
A method for manufacturing a housing. In the surface adjustment treatment step, the casing is immersed in the second treatment liquid stored in the surface adjustment treatment tank, and the spray nozzle disposed in the surface adjustment treatment tank is directed toward the thin film formation site. Removing bubbles adhering to the thin film formation site by the flow of the second treatment liquid sprayed
The manufacturing method of the housing | casing of Claim 1. The liquid flow of the second treatment liquid sprayed from the spray nozzle hits a predetermined thick film forming part that makes the film thickness of the corrosion-resistant film thicker than the thin film forming part in the base material surface. The surface adjustment processing step is performed in a state where the cover member for suppressing the surface is disposed in the surface adjustment processing tank.
The manufacturing method of the housing | casing of Claim 2. A film forming apparatus for forming a corrosion-resistant film on the surface of a base material of a housing using a magnesium alloy,
A corrosion-resistant film treatment part for immersing the casing in a first treatment liquid for forming the corrosion-resistant film on the substrate surface to form the corrosion-resistant film on the substrate surface;
The second treatment liquid in the surface adjustment treatment tank has a surface adjustment treatment tank for storing a second treatment liquid for suppressing a reaction between the first treatment liquid and the substrate surface in the corrosion-resistant film treatment unit. A surface adjustment processing unit for immersing the casing in a surface to form a surface adjustment film on the substrate surface;
With
The surface adjustment processing unit removes bubbles generated and adhered to a predetermined thin film forming portion that makes the thickness of the corrosion-resistant film thinner than other portions of the base material surface by reaction with the second processing liquid. A bubble removing device that further
Film forming device. The surface adjustment processing unit further includes an injection nozzle that is arranged in the surface adjustment processing tank and that injects the second processing liquid toward the thin film formation site, and the second processing is injected from the injection nozzle. Removing bubbles adhering to the thin film forming site by the liquid flow;
The film forming apparatus according to claim 4. The surface adjustment processing unit is a cover member disposed in the surface adjustment processing tank, and a predetermined thick film formation that makes the film thickness of the corrosion-resistant film out of the surface of the base material thicker than the thin film formation site. A cover member that suppresses the liquid flow of the second processing liquid sprayed from the spray nozzle from being applied to the portion is further included,
The film forming apparatus according to claim 5.

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