阅读说明：本技术 一种电镀层厚度的测量方法 (Method for measuring thickness of electroplated layer ) 是由 吴秀冰 冯锡泽 郑利明 陈英贤 杨艳丽 于 2021-07-07 设计创作，主要内容包括：本发明公开了一种电镀层厚度的测量方法,包括如下步骤：将热固性树脂和固化剂混合得到透明的树脂混合液；取待测样片,所述待测样片包括塑料基底以及覆于在所述塑料基底表面的电镀层,将所述待测样片置于所述树脂混合液中,并使所述待测样片垂直于树脂混合液的液面；使所述树脂混合液固化,树脂混合液固化后待测样片被固定于固化后的热固性树脂中；对固化后的热固性树脂进行研磨,使待测样片的断面露出来；对所述断面进行检测,得到电镀层的厚度。本发明的测量方法可提高研磨后的断面与待测样片的垂直程度,使得研磨后的电镀层断面清晰可辨。而且本发明的工序简单方便,后续研磨方便,省时,高质量,并能实现自动化、大批量操作。(The invention discloses a method for measuring the thickness of an electroplated layer, which comprises the following steps: mixing thermosetting resin and a curing agent to obtain a transparent resin mixed solution; taking a sample to be tested, wherein the sample to be tested comprises a plastic substrate and an electroplated layer coated on the surface of the plastic substrate, placing the sample to be tested in the resin mixed liquid, and enabling the sample to be tested to be perpendicular to the liquid level of the resin mixed liquid; solidifying the resin mixed solution, and fixing the sample wafer to be detected in the solidified thermosetting resin after the resin mixed solution is solidified; grinding the cured thermosetting resin to expose the section of the sample wafer to be tested; and detecting the section to obtain the thickness of the electroplated layer. The measuring method can improve the vertical degree of the ground section and the sample wafer to be measured, so that the ground electroplated layer section is clear and identifiable. The invention has simple and convenient working procedure, convenient subsequent grinding, time saving and high quality, and can realize automatic and large-scale operation.)

1. A method for measuring the thickness of an electroplated layer is characterized in that: the method comprises the following steps:

mixing thermosetting resin and a curing agent to obtain a transparent resin mixed solution;

taking a sample to be tested, wherein the sample to be tested comprises a plastic substrate and an electroplated layer coated on the surface of the plastic substrate, placing the sample to be tested in the resin mixed liquid, and enabling the sample to be tested to be perpendicular to the liquid level of the resin mixed liquid;

solidifying the resin mixed solution, and fixing the sample wafer to be detected in the solidified thermosetting resin after the resin mixed solution is solidified;

grinding the cured thermosetting resin to expose the section of the sample wafer to be tested;

and detecting the section to obtain the thickness of the electroplated layer.

2. The method for measuring a thickness of a plated layer according to claim 1, comprising the steps of: the curing peak temperature of the resin mixed liquid is lower than the thermal deformation temperature of the plastic substrate.

3. The method for measuring a thickness of a plated layer according to claim 1, comprising the steps of: the mass ratio of the thermosetting resin to the curing agent is about 5-10: 1, preferably about 8.3: 1.

4. the method for measuring a thickness of a plated layer according to claim 1, comprising the steps of: and in the step of placing the sample wafer to be detected in the resin mixed liquid, the resin mixed liquid at least submerges the section of the sample wafer to be detected.

5. The method for measuring a thickness of a plated layer according to claim 1, comprising the steps of: the method comprises the following steps of placing the sample to be tested in the resin mixed solution, and enabling the sample to be tested to be perpendicular to the liquid level of the resin mixed solution: fixing the sample wafer to be tested by using a fixing clamp, vertically placing the sample wafer to be tested into a container, and pouring the resin mixed liquid into the container.

6. A method for measuring the thickness of a plated layer according to claim 5, comprising the steps of: the manufacturing method of the fixing clip comprises the following steps: and (3) inwards curling two opposite edges of a rectangular metal sheet on the same surface of the metal sheet to respectively form two symmetrical cylinders, and curling until the two cylinders are tangent to obtain the fixing clamp.

7. A method for measuring the thickness of a plated layer according to claim 5, comprising the steps of: the container is a curing movable mould which comprises a chassis and a mould body, wherein the mould body is detachably fixed on the chassis and is combined with the chassis to form a cavity with an upper opening.

8. The method for measuring a thickness of a plated layer according to claim 1, comprising the steps of: the curing temperature is 10-80 ℃, and preferably 20-30 ℃.

9. The method for measuring a thickness of a plated layer according to claim 1, comprising the steps of: the transparency of the cured thermosetting resin is more than or equal to 70 percent, preferably more than or equal to 80 percent.

10. The method for measuring a thickness of a plated layer according to claim 1, comprising the steps of: before grinding the cured thermosetting resin, the method also comprises the step of demoulding the cured thermosetting resin from the curing movable mould; preferably, the demolding step is performed by using a demolding jig, and the demolding jig comprises a base, an ejection column and an ejection part; the ejection column is vertically and fixedly arranged on the base and forms an inverted T shape with the base; the overall shape of the ejection part is T-shaped, and the cross section shape and the size of the top end of the ejection part are the same as those of the containing cavity of the curing movable mold; the lower end of the ejection part is provided with a groove with a downward opening, and the size of the groove can be embedded into the ejection column; preferably, the demolding process is to remove the chassis of the curing movable mold; and embedding the ejection column of the demolding jig into the groove of the ejection part, ejecting the top end of the ejection part to the bottom of the solidified resin, and then releasing the solidified resin from the cavity of the movable solidification mold.

Technical Field

The invention relates to the technical field of electroplated film detection, in particular to a method for measuring the thickness of an electroplated layer.

Background

In many automobile parts, resin is used as a base material, and the appearance of the resin base material can be improved by forming a plating film on the resin, thereby compensating for the defects of the resin, giving properties to metal, and fully exerting the characteristics of the resin and the metal. The thickness of the metal plating film can directly reflect the properties of the plating layer such as bonding force (copper layer) and corrosion resistance (nickel layer), so that it is necessary to grasp the film thickness level strictly according to the standard and estimate the properties of the product. The electroplated film of resin generally comprises three layers, from outside to inside, an outer layer (such as a chromium layer) for decoration, a nickel layer for corrosion prevention and a copper layer for improving the adhesion of the electroplated film, as shown in fig. 1, the electroplated film can comprise other different electroplated layers according to different requirements. When the thickness of the plated film is measured, it is required that the section of the plated film is clear enough to clearly distinguish each plated layer.

For measuring the thickness of the electroplated film, the measuring methods of the related technologies mainly comprise a coulometric method, a microscopic section measuring method and an X-ray method, wherein the microscopic section measuring method is widely applied due to the intuitive result, simple equipment and relatively convenient operation. The measuring process of the microscope section measuring method comprises the steps of cutting a test piece from a sample to be measured, holding the test piece by hand, vertically grinding the section of the test piece by using sand paper to enable the section to be flat and the coating to be clear, and finally observing and measuring the section by using a microscope. Due to the limitation of the shape of the test piece and the great difference between the resin base material and the material of the electroplating film, the sand paper is difficult to be vertical to the section in the grinding process, the ground section is fuzzy, and different coatings are difficult to distinguish; the method is time-consuming to operate, has very high requirements on the proficiency of grinding personnel, and cannot realize automation in the process.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a method for measuring the thickness of the electroplating layer, which can improve the detection accuracy of the thickness of the electroplating layer.

Specifically, the method for measuring the thickness of the electroplating layer comprises the following steps:

mixing thermosetting resin and a curing agent to obtain a transparent resin mixed solution;

taking a sample to be tested, wherein the sample to be tested comprises a plastic substrate and an electroplated layer coated on the surface of the plastic substrate, placing the sample to be tested in the resin mixed liquid, and enabling the sample to be tested to be perpendicular to the liquid level of the resin mixed liquid;

solidifying the resin mixed solution, and fixing the sample wafer to be detected in the solidified thermosetting resin after the resin mixed solution is solidified;

grinding the cured thermosetting resin to expose the section of the sample wafer to be tested;

and detecting the section to obtain the thickness of the electroplated layer.

The method for detecting the thickness of the electroplating layer has at least the following beneficial effects:

because the hardness of the electroplated layer is harder than that of the plastic substrate and is limited by the shape of the sample wafer to be detected and the proficiency of an operator, when the cross section is ground by adopting the method in the prior art, the conditions of unbalanced stress and inclination often occur, so that the ground cross section is fuzzy, and different electroplated layers are difficult to distinguish. According to the invention, the sample wafer to be tested is embedded in the solidified thermosetting resin, so that the subsequent grinding area can be obviously increased, the condition of unbalanced stress caused by too small section of the sample wafer to be tested is avoided, and the vertical degree of the ground section and the sample wafer to be tested is improved; in the curing process, the sample wafer to be detected is vertical to the liquid level of the resin mixed liquid, so that the vertical degree of the ground section and the sample wafer to be detected can be further improved, and the ground electroplated layer section is clear and distinguishable.

In some embodiments of the present invention, the curing peak temperature of the resin mixture is lower than the heat distortion temperature of the plastic substrate. The plastic substrate of the sample wafer to be measured can be prevented from deformation by curing at low temperature, so that the measurement error is reduced.

In some embodiments of the invention, the thermosetting RESIN comprises an epoxy RESIN, such as EPOFIX RESIN by Struers.

In some embodiments of the invention, the curing agent comprises a polyethylene diamine condensate, such as EPOXX HARDENER by Struers.

In some embodiments of the invention, the mass ratio of the thermosetting resin to the curing agent is 5-10: 1, preferably about 8.3: 1(25:3). Too little curing agent will result in too long a curing time, thus increasing the detection time, while too much curing agent may present a risk of yellowing. According to the invention, the resin mixed liquid has proper curing time and good transparency, and the curing peak temperature of the resin mixed liquid is not higher than 80 ℃ in the proportion, so that the plastic substrate can be prevented from deforming.

In some embodiments of the invention, the plastic substrate comprises any one of an ABS (acrylonitrile-butadiene-styrene copolymer) substrate, a PC + ABS substrate.

In some embodiments of the present invention, the electroplated layer includes at least two metal coatings of different materials, for example, a copper coating and a nickel coating, which are sequentially stacked, and may further include a chromium coating, a gold coating, a silver coating, a cobalt coating, and the like, and the stacking order thereof may be determined according to production requirements.

In some embodiments of the present invention, in the step of placing the sample to be tested in the resin mixture, the resin mixture immerses at least a cross section of the sample to be tested.

In some embodiments of the present invention, the step of placing the sample to be measured in the resin mixed solution and making the sample to be measured perpendicular to the liquid level of the resin mixed solution is specifically: fixing the sample wafer to be tested by using a fixing clamp, vertically placing the sample wafer to be tested into a container, and pouring the resin mixed liquid into the container.

In some embodiments of the present invention, the method for manufacturing the fixing clip comprises: two opposite edges of a rectangular metal sheet (such as a copper sheet) are curled inwards on the same surface of the metal sheet to respectively form two symmetrical cylinders, and the two cylinders are curled until the two cylinders are tangent to obtain the fixing clamp. The object is embedded at the tangent position of the two cylinders and is clamped and fixed under the action of the curling elastic force of the two cylinders. The two cylinders can be circular or elliptical, the diameters of the two cylinders can be set according to actual conditions, and the sample wafer to be tested can be embedded and fixed at the tangent position of the two cylinders.

In some embodiments of the present invention, the container is a movable curing mold, and the movable curing mold comprises a chassis and a mold body, wherein the mold body is detachably fixed on the chassis and is combined with the chassis to form a cavity with an upper opening. The cavity can be used for placing a fixing clamp for clamping a sample wafer to be tested and pouring resin mixed liquid. Before a fixing clamp for clamping a sample wafer to be tested is placed, the inner surface of the cavity is coated with silicone oil for subsequent demoulding.

In some embodiments of the invention, the method of curing is static curing. The curing temperature is 10-80 ℃, and preferably 20-30 ℃; the curing temperature refers to the temperature of the environment where the resin mixed liquid is located during curing. The curing time is 5-15 h, preferably 12 h. In the curing process, the curing exothermic peak temperature of the resin mixed solution is 35-45 ℃, and preferably about 40 ℃.

In some embodiments of the invention, the cured thermosetting resin has a transparency of 70% or more, preferably 80% or more.

In some embodiments of the present invention, before grinding the cured thermosetting resin, the step of releasing the cured thermosetting resin from the curing movable mold is further included.

In some embodiments of the present invention, the demolding process is specifically to remove the bottom plate of the cured movable mold, and then eject the cured thermosetting resin from the cavity of the cured movable mold.

In some embodiments of the invention, the demolding step is performed using a demolding tool comprising a base, an ejection post, and an ejection portion; the ejection column is vertically and fixedly arranged on the base and forms an inverted T shape with the base; the overall shape of the ejection part is T-shaped, and the cross section shape and the size of the top end of the ejection part are the same as those of the containing cavity of the curing movable mold; the lower end of the ejection part is provided with a groove with a downward opening, and the size of the groove can be embedded into the ejection column. The specific demolding process is that the chassis of the curing movable mold is removed; and embedding the ejection column of the demolding jig into the groove of the ejection part, ejecting the top end of the ejection part to the bottom of the solidified resin, and then releasing the solidified resin from the cavity of the movable solidification mold.

In some embodiments of the present invention, the grinding includes a step of grinding with coarse sandpaper, fine sandpaper and polishing cloth in this order, wherein the mesh number of the coarse sandpaper is 500-1000 mesh, and the mesh number of the fine sandpaper is 1500-2500 mesh. In practice, the grinding can be carried out by hand grinding or by an automatic polishing machine. The method of the invention can adopt manual grinding and can also adopt an automatic polishing machine to realize automatic and large-batch grinding.

In some embodiments of the invention, the method of detecting the cross-section comprises microscopic detection.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the solidification and embedding sample preparation is carried out before the grinding of the section of the sample wafer to be detected, and the sample wafer to be detected is embedded in the solidified thermosetting resin, so that the condition of unbalanced stress caused by too small section of the sample wafer to be detected is avoided, and the vertical degree of the ground section and the sample wafer to be detected is improved; in the curing process, the sample wafer to be detected is vertical to the liquid level of the resin mixed liquid, so that the vertical degree of the ground section and the sample wafer to be detected can be further improved, and the ground electroplated layer section is clear and distinguishable. The invention has simple and convenient working procedure, convenient subsequent grinding, time saving and high quality, can realize automatic and large-batch operation, and improves great convenience for measuring the thickness of the resin plating layer.

The invention flexibly adopts various tools and adjusts various operations in the processes of inlaying, sample preparation and demoulding, for example, a specific fixed clamp is adopted to ensure the verticality of a sample wafer to be tested in thermosetting resin, the demoulding tool with a specific structure can conveniently meet the demoulding requirement of curing movable moulds with different specifications, the structure is simple, the stress is uniform, the demoulding is easy, the service life of the curing movable mould is prolonged, and the sample preparation quality is improved.

Drawings

FIG. 1 is a schematic view showing a structure of a plated film of a resin;

FIG. 2 is a flowchart of a method for measuring the thickness of a plating layer;

FIG. 3 is a schematic structural view of a movable curing mold, wherein A is a front view and B is a top view;

FIG. 4 is a pictorial view of a retaining clip for holding a test strip;

FIG. 5 is a schematic structural view of the demolding tool;

FIG. 6 is an assembly schematic of the demolding of the cured resin with a demolding tool;

FIG. 7 is a result of observation of a plating layer of the example;

FIG. 8 is an observation result of a plating layer of a comparative example;

reference numerals: the method comprises the steps of solidifying the movable mold 10, the chassis 101, the mold body 102, the fixed clamp 20, the first clamping part 201, the second clamping part 202, the demolding jig 30, the base 301, the ejection column 302 and the ejection part 303.

Detailed Description

The technical solution of the present invention is further described below with reference to specific examples. The starting materials used in the following examples, unless otherwise specified, are available from conventional commercial sources; the processes used, unless otherwise specified, are conventional in the art.

Examples

The invention provides a method for measuring the thickness of a plating layer on the surface of a plastic substrate, and a flow chart is shown in figure 2. The tools required in the measurement process include a curing movable mold 10, a stationary clamp 20, and a demolding jig 30.

As shown in fig. 3, the movable curing mold 10 includes a base plate 101 and a mold body 102, wherein the mold body 102 is detachably fixed on the base plate 101, and is combined with the base plate 101 to form a circular cavity with an upper opening, and the size of the cavity can be adjusted according to actual conditions, for example, the diameter of the cavity can be designed to be 30mm or 40mm, and the height is less than 30 mm.

As shown in fig. 4, the fixing clip 20 includes a first clamping portion 201 and a second clamping portion 202, wherein the first clamping portion 201 and the second clamping portion 202 are both in a circle shape, and the first clamping portion 201 and the second clamping portion 202 are tangent. Specifically, the method for manufacturing the fixing clip 20 includes curling two opposite edges of a rectangular metal sheet (such as a copper sheet) inward on the same surface of the metal sheet to form two symmetrical cylinders respectively, and curling the two cylinders until the two cylinders are tangent to each other, thereby obtaining the fixing clip 20. Two cylinders, a first clamping portion 201 and a second clamping portion 202, are rolled up. An object is inserted into a position where the first clamping portion 201 and the second clamping portion 202 are tangent to each other, and the object is clamped and fixed by the curling elastic force of the first clamping portion 201 and the second clamping portion 202.

As shown in fig. 5, the demolding tool 30 includes a base 301, an ejector post 302, and an ejector portion 303. The ejection column 302 is vertically fixed on the base 301, and forms an inverted T shape with the base 301. The overall shape of the ejection part 303 is T-shaped, and the cross-sectional shape and size of the top end thereof are the same as those of the cavity of the movable curing mold 10; the lower end of the ejecting part 303 is provided with a groove with a downward opening, and the groove is sized to be inserted into the ejecting column 302.

The method for measuring the thickness of the electroplating layer comprises the following steps:

(1) a thin layer of silicone oil is brushed on the surface of the inner cavity of the curing movable mold 10 by a brush.

(2) Selecting appropriate transparent normal temperature curing epoxy RESIN [ EPOFIX RESIN of Struers, the components of which comprise 2, 2-bis (4-glycidoxyphenyl) propane (60-90%), glycidol 12-14 alkyl ether (10-40%) ] and curing agent [ EPOFIX HARDENER of Struers, the components of which are polyethylene diamine triscale (100%) ], according to the weight ratio of 25: 3, mixing the epoxy resin and the curing agent according to the mass ratio, uniformly stirring, standing for 2-5 min to dissipate bubbles, and obtaining transparent resin mixed liquid. The curing exothermic peak temperature of the resin mixed liquid in the proportion is 40 ℃.

(3) A partial region was cut out as a test piece from a resin plated article including a plastic substrate (an ABS substrate, or a composite substrate of PC and ABS) and a plated layer (including a copper layer and a nickel layer laminated) provided on the surface of the plastic substrate. The test strip is vertically inserted into the fixed clip 20 at a position where the first clamping portion 201 and the second clamping portion 202 are tangent (as shown in fig. 4), and then the fixed frame 20 is placed into the cavity of the movable curing mold 10 as vertically as possible.

(4) And (3) using tweezers to stabilize the test piece, pouring the resin mixed solution prepared in the step (2) into the containing cavity of the curing movable mold 10, and just immersing the top of the test piece. Standing and curing at room temperature for 12 h. After the curing, the test piece was fixed inside the cured resin.

(5) After the curing is finished, the base plate 101 of the curing movable mold 10 is removed. The ejection columns 302 of the demolding jig 30 are embedded in the grooves of the ejection portions 303, the top ends of the ejection portions 303 are abutted against the bottom of the cured resin, as shown in fig. 6, and then the cured resin is removed from the cavity of the curing movable mold 10.

(6) The top of the cured resin was vertically ground using coarse sandpaper (about 800 mesh), fine sandpaper (about 2000 mesh) and a polishing cloth in this order, so that the cross section of the top of the test piece was clearly exposed.

(7) After the grinding was completed, the cross section of the top of the test piece was observed with a microscope.

The time for completing the test steps is about 15 min; as shown in FIG. 7, the observation result of a test piece, the copper layer and the nickel layer were clearly distinguished by a microscope.

Comparative example

Test pieces having the same size and shape were cut from the same resin-plated product as in the example, and the test pieces were held by hand, and the cross sections of the test pieces were vertically ground using coarse sandpaper (about 800 mesh), fine sandpaper (about 2000 mesh), and a polishing cloth in this order, so that the cross sections of the test pieces were clearly exposed.

After grinding for 15min, the top section of the test piece was observed with a microscope, and the result is shown in FIG. 8. As can be seen from fig. 8, the cross section after the conventional hand-held grinding is blurred and the nickel layer and the copper layer cannot be distinguished under the same grinding time. And the copper layer and the nickel layer can be clearly distinguished after the grinding is continued for 15 min. That is, it takes at least 30min to obtain a qualified test piece that can clearly distinguish between the copper layer and the nickel layer by using the conventional hand-held grinding method.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.