Process capable of improving and solving electrophoresis primary flow mark

Abstract

The invention provides a technology capable of improving and solving electrophoresis primary flow marks. The technology comprises the following steps that S1, a workpiece obtained after pretreatment is soaked, and meanwhile electrolytic treatment is achieved; s2, the workpiece subjected to soaking electrolysis treatment is cleaned; and S3, the cleaned workpiece is subjected to electrophoresis treatment. According to the method, soaking before electrophoresis is changed into the electrolysis procedure of the specific electrolyte, primary flow marks and particles in the electrophoresis process are effectively reduced, the polishing requirement for the product is lowered, the overall appearance qualification rate of the product is increased, and the quality and production efficiency of the electrophoresis product are effectively improved. Meanwhile, pollution of chemical agents and grease substances to an electrophoresis tank is reduced, and the salt fog resistance and corrosion resistance of the product are stabilized.

Description

Technical Field

[0001] The invention belongs to the technical field of metal workpiece surface treatment, and in particular relates to a process capable of improving and solving electrophoresis primary flow marks. Background Art

[0002] In the traditional electrophoresis process, the special structure of the product (blind holes, slits, and cold solder joints) is very likely to cause primary flow marks and particle problems during the electrophoresis process, which will not only lead to a decline in the appearance quality of the product, but also require a lot of grinding work in the subsequent processing of the product, and may even require rework and then spraying. In addition, the electrophoretic paint on the surface of the product is damaged after grinding, which greatly reduces the salt spray resistance and corrosion resistance of the product. At the same time, during the pre-electrophoresis treatment, the chemical agents and grease substances remaining in the blind holes, slits, etc. of the workpiece will pollute the electrophoresis tank and affect the electrophoresis effect. In addition, the traditional immersion process before electrophoresis cannot effectively remove the above impurities, making it difficult to meet the needs of high-quality electrophoresis, which seriously restricts the quality improvement of electrophoretic products. Summary of the invention

[0003] The purpose of the present invention is to provide a process that can improve and solve the electrophoresis primary flow mark, aiming to solve the above-mentioned technical problems.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a process for improving and solving the problem of electrophoresis primary flow marks, comprising the following steps: S1, soaking the workpiece after pretreatment and simultaneously performing electrolytic treatment; S2, cleaning the workpiece after soaking and electrolytic treatment; S3, performing electrophoretic treatment on the cleaned workpiece.

[0005] As a preferred embodiment of the present invention, in the step S1, when performing electrolysis, the electrolyte is first prepared, and a first additive containing an ether or ester compound is mixed with a second additive containing an organic acid, so that the first additive accounts for 1.2%-3.0% in the electrolyte, the pH value is controlled at 5.4-6.2, and the conductivity is 750-2100μs / cm.

[0006] As a preferred embodiment of the present invention, the first additive is one or more of isopropylene, ethylene glycol ethyl ether, ethylene glycol butyl ether, ethylene glycol hexyl ether, and ethyl acetate.

[0007] As a preferred embodiment of the present invention, the second additive is one of acetic acid or lactic acid.

[0008] As a preferred embodiment of the present invention, in the step S1, the same operating voltage is maintained during the electrolysis treatment and the electrophoresis treatment.

[0009] As a preferred embodiment of the present invention, in the step S1, under the action of a rectifier, the electrolytic cell is powered on and the voltage is controlled at 100-300V, and the metal workpiece is electrolyzed for 20-120 seconds. If the power permits, the electrolytic cell is connected in parallel to the electrophoresis tank with the same rectifier, or a rectifier can be configured separately.

[0010] As a preferred embodiment of the present invention, in the step S2, the electrolytic cell is made of an insulating material or a metal material with a fiberglass insulating coating on the inner wall.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] 1) In the electrophoresis method of the present invention, the immersion before electrophoresis is changed to an electrolysis process of a specific electrolyte. The electrolyte is accurately prepared, one or more ether or ester compounds such as isopropylene and ethylene glycol ethyl ether are selected as the first additive, and the proportion is controlled at 1.2%-3.0%. The pH value of the electrolyte is strictly controlled at 5.4-6.2, and the conductivity is controlled at 750-2100μs / cm. The electrolysis effect is effectively improved, and the stability and safety of the electrolysis process are ensured. In addition, gas is generated during the electrolysis process. In particular, the workpiece as the cathode will generate hydrogen with a volume twice that of the oxygen precipitated by the anode. Bubbles overflow from the liquid, which is equivalent to stirring the liquid. The liquid containing chemicals remaining in the special structure will be fully mixed with the electrolyte to dilute the concentration of the chemicals. During the electrophoresis process, flocculation (primary flow marks) of the electrophoretic paint will not be caused, thereby ensuring the quality of the final product processing.

[0013] 2) The present invention changes the immersion before electrophoresis into an electrolysis process of a specific electrolyte, which effectively reduces primary flow marks and particles during the electrophoresis process, reduces the need for product polishing, and improves the overall appearance qualification rate of the product. At the same time, it stabilizes the salt spray resistance and corrosion resistance of the product, reduces the pollution of the electrophoresis tank by chemicals and oils and fats, and further improves the quality and production efficiency of electrophoresis products. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0015] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0017] Example

[0018] See also Figure 1 The present invention provides the following technical solution: A process for improving and solving the electrophoresis primary flow mark, comprising the following steps:

[0019] S1, immersing the pre-treated workpiece and simultaneously performing electrolytic treatment;

[0020] S2, cleaning the workpiece after immersion electrolysis treatment;

[0021] S3, performing electrophoresis treatment on the cleaned workpiece.

[0022] The pre-treated workpiece is immersed and electrolytically treated at the same time. After the workpiece is placed in a specific electrolytic tank, the electrolyte is fully in contact with the workpiece. By applying an electric field in the electrolyte, the residual particles and electrolytes in the special structure of the workpiece are removed, making it more conducive to the subsequent electrophoresis process;

[0023] It should be noted that the electrophoretic paint working fluid is a colloidal solution, which will flocculate when it encounters a strong electrolyte or an electrolyte of a different charge. The significance of the present invention using electrolysis instead of immersion washing is that due to the special structure of the workpiece, after pre-treatment, chemicals or particles will remain in the special structure of the workpiece. Due to the particularity of the structure, these residues cannot be washed out (capillary phenomenon). The significance of electrolysis is that the electrolysis process will generate gas, especially the workpiece as a cathode, which will generate a large volume of hydrogen. Bubbles overflow from the liquid, which is equivalent to stirring the liquid. The liquid containing chemicals remaining in the special structure will be fully mixed with the electrolyte, diluting the concentration of the chemicals. In the electrophoretic process, no flocculation (primary flow mark) of the electrophoretic paint will be caused, thereby ensuring the quality of the final product processing.

[0024] After the electrolysis treatment, the product is further washed with water and then enters the electrophoresis stage, which reduces the generation of primary flow marks of electrophoresis, improves the quality and appearance of the electrophoretic coating, and ensures the final product quality of the workpiece.

[0025] In this embodiment: In the S1 step, when electrolysis is performed, the electrolyte is first prepared, and a first additive containing an ether or ester compound is mixed with a second additive containing an organic acid, so that the first additive accounts for 1.2%-3.0% in the electrolyte, the pH value is controlled at 5.4-6.2, and the conductivity is 750-2100μs / cm, wherein the first additive is one or more of isopropylene, ethylene glycol ethyl ether, ethylene glycol butyl ether, ethylene glycol hexyl ether, and ethyl acetate, and the second additive is one of acetic acid or lactic acid.

[0026] Specifically, a first additive containing an ether or ester compound is mixed with a second additive containing an organic acid, and the proportion of the first additive is controlled at 1.2%-3.0%, so that the additive can fully exert its effect, while other properties of the electrolyte will not be affected due to excessive addition;

[0027] The second additive contains organic acid, which can adjust the pH value of the electrolyte. When the pH value is controlled within the range of 5.4-6.2, the chemical reaction in the electrolyte can proceed at an optimal rate, which not only ensures the effect of electrolysis, but also avoids adverse reactions caused by too high or too low pH value. The conductivity is controlled between 750-2100μs / cm. The appropriate conductivity can ensure the normal occurrence of the electrolytic reaction, so that all parts of the workpiece surface can be effectively electrolytically treated, while avoiding excessive current and excessive heat generation, ensuring the stability of the electrolytic reaction.

[0028] In this embodiment: in the step S1, the same working voltage is maintained during the electrolysis treatment and the electrophoresis treatment.

[0029] Specifically, during the electrolytic treatment stage, the workpiece is placed in an electrolytic cell and an electrolytic reaction is achieved by applying an electric field. When the electrolytic treatment and the electrophoretic treatment use the same working voltage, the electrolytic reaction can be ensured to proceed normally while avoiding corrosion of the workpiece due to excessive voltage.

[0030] In this embodiment: in the step S1, under the action of the rectifier, the electrolytic cell is powered on and the voltage is controlled at 100-300V, and the metal workpiece is electrolyzed for 20-120 seconds. If the power allows, the electrolytic cell is connected in parallel to the electrophoresis tank with the same rectifier, or a separate rectifier can be configured.

[0031] Specifically, when the electrolytic cell is powered on, the voltage is controlled at 100-300V, and the electrolysis time is controlled at 20-120 seconds, so that the electrolysis reaction can be fully carried out and residual electrolyte and particles in the special structure of the workpiece can be effectively removed. In addition, under the premise of power permitting, the electrolytic cell is connected in parallel to the electrophoresis cell with the same rectifier, which can save equipment cost and space, and is also convenient for unified management and control; and a separate rectifier can better control the parameters of the electrolysis process, avoid mutual interference with the electrophoresis process, and then meet different electrolysis needs.

[0032] In this embodiment: in the step S1, the electrolytic cell is made of an insulating material or a metal material with a glass fiber reinforced plastic insulating coating on the inner wall.

[0033] Specifically, in actual industrial production, the electrolytic cell needs to be in contact with the electrolyte for a long time, and the electrolyte may be corrosive to a certain extent. The use of insulating materials or metal materials with insulating coatings can effectively solve the corrosion problem and ensure the stability and reliability of the electrolytic cell during long-term use, thereby ensuring the effect of the electrolytic treatment and the quality of the electrophoretic products.

[0034] The process of the present invention uses degreasing and phosphating to remove surface oil and form a chemical conversion film when pre-treating the workpiece, so that the workpiece surface is clean and suitable for subsequent treatment. Then, the pre-treated workpiece is placed in a specific electrolytic cell, and in an electrolyte containing a first additive of an ether or ester compound and a second additive containing an organic acid in a specific ratio, the pH value is controlled to be 5.4-6.2 and the conductivity is controlled to be 750-2100 μs / cm. A voltage of 100-300V is applied for electrolysis for 20-120 seconds, and residual electrolytes and particles of a special structure are removed under the action of an electric field. The electrolysis treatment and the electrophoresis treatment maintain the same working voltage, simplifying the electrical control system and thereby reducing the primary flow mark of the electrophoresis, thereby improving the quality of the electrophoresis coating, the appearance effect and the product quality.

[0035] It should be supplemented that: in order to further improve the quality of electrophoresis processing of the workpiece, the electrolysis step in step S1 can also be performed twice or more to further remove residual impurities on the surface of the workpiece.

[0036] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technology of the present invention, which do not depart from the content of the technical solution of the present invention, are within the scope of the technical solution of the present invention.

Claims

1. A process for improving and solving the primary flow mark of electrophoresis, characterized in that: The following steps are involved: S1, immersing the pre-treated workpiece and simultaneously performing electrolytic treatment; S2, cleaning the workpiece after immersion electrolysis treatment; S3, performing electrophoresis treatment on the cleaned workpiece.

2. A process for improving and solving electrophoresis primary flow marks according to claim 1, characterized in that: In the step S1, when electrolysis is performed, the electrolyte is first prepared, and a first additive containing an ether or ester compound is mixed with a second additive containing an organic acid, so that the first additive accounts for 1.2%-3.0% of the electrolyte, the pH value is controlled at 5.4-6.2, and the conductivity is 750-2100 μs / cm.

3. A process for improving and solving electrophoresis primary flow marks according to claim 2, characterized in that: The first additive is one or more of isopropylene, ethylene glycol ethyl ether, ethylene glycol butyl ether, ethylene glycol hexyl ether, and ethyl acetate.

4. A process for improving and solving electrophoresis primary flow marks according to claim 2, characterized in that: The second additive is one of acetic acid or lactic acid.

5. A process for improving and solving electrophoresis primary flow marks according to claim 2, characterized in that: In the step S1, the same working voltage is maintained during the electrolysis treatment and the electrophoresis treatment.

6. A process for improving and solving primary flow marks in electrophoresis according to claim 5, characterized in that: In the step S1, under the action of the rectifier, the electrolytic cell is powered on and the voltage is controlled at 100-300V. The metal workpiece is subjected to cathode electrolysis for 20-120 seconds. If the power allows, the electrolytic cell is connected in parallel to the electrophoresis tank with the same rectifier, or a separate rectifier can be configured.

7. A process for improving and solving primary flow marks in electrophoresis according to claim 6, characterized in that: In the step S1, the electrolytic cell is made of an insulating material or a metal material with a glass fiber reinforced plastic insulating coating on the inner wall.

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