A processing method for mold fire pattern processing

Abstract

The present application discloses a method for processing mold spark patterns, comprising the following steps: processing the mold cavity to obtain a spark pattern surface; polishing the convex points on the spark pattern surface; performing a pattern patching process on the polished convex points to match the spark pattern surface; and post-processing the mold cavity after the pattern patching. The beneficial effects of the present application: by pre-polishing and polishing the convex points on the spark pattern surface, then pattern patching the convex points, and finally post-processing the pattern patched convex points, the convex points can be processed and still form a texture that matches the original spark pattern surface, making the processing of the convex points more natural, and will not cause damage to the spark pattern surface of the mold cavity, thereby achieving a more beautiful and consistent appearance effect on the molded product, and this method greatly improves the appearance quality of the product.

Description

Technical Field

[0001] The present application relates to the technical field of mold surface treatment, and in particular to a method for processing mold spark patterns. Background Art

[0002] At present, many products we use in our daily life are made by injection molding, and people have higher and higher requirements on the appearance quality of plastic products (such as shells) made by injection molding. The surfaces of these shell products often have various decorative effects. For example, in order to increase market competitiveness, some products need to have a textured effect on the shell.

[0003] In order to achieve the above purpose, it is necessary to set a texture in the mold cavity. The existing method is generally through electric spark processing, that is, the spark pattern produced is the ablation mark left on the mold surface when the copper is discharged. The spark pattern surface produced by the mold discharge is pitting, and the coarseness of the pitting can be adjusted by the current of the spark machine. After electric spark processing, such as Figure 1 As shown in the figure, many processing convex points will be formed on the mold surface, and the existing processing method often adopts grinding and polishing. Although this method can remove the convex points, it may damage the surface during the processing. At the same time, the polished surface after processing cannot fit the original surface, which affects the aesthetics of the subsequent molded product. Therefore, a processing method for mold spark pattern processing is proposed to solve the above technical problems. Summary of the invention

[0004] One of the purposes of the present application is to provide a method for processing mold fire patterns.

[0005] To achieve the above objectives, the technical solution adopted in the present application is: a method for processing mold spark pattern, comprising the following steps: S100: processing the mold cavity to obtain a spark pattern surface; S200: polishing the convex points on the spark pattern surface; S300: performing patching on the polished convex points to match them with the spark pattern surface; S400: post-processing the mold cavity after patching.

[0006] Preferably, in step S200, before the polishing process is performed, the following step is also included: filling the depressions of the spark pattern surface to form the convex points.

[0007] Preferably, in step S200, the height of the convex point after polishing is greater than or equal to the height of the spark texture.

[0008] Preferably, in step S300, the patching process includes the following steps: firstly, the convex point is subjected to manual electric spark treatment, and then, the convex point is etched by a corrosive solution to obtain a texture, so that the texture and the spark pattern surface are matched.

[0009] Preferably, the etching solution comprises, by weight, 10-15 parts of nitric acid, 10-15 parts of sulfuric acid, 10-15 parts of hydrochloric acid, 5-12 parts of hydrofluoric acid, 5-10 parts of cupric chloride, 1-5 parts of a surfactant, and 80-140 parts of deionized water.

[0010] Preferably, the etching time of the convex point by the etching solution is 3-8 seconds.

[0011] Preferably, the corrosive solution corrodes the protrusion for 5 seconds.

[0012] Preferably, during the etching process of the convex point, if the height of the convex point is greater than the height of the spark pattern surface, the etching process is repeated until the height of the convex point is less than or equal to the height of the spark pattern surface.

[0013] Preferably, in step S300, an anti-corrosion sheet is adapted to be provided in the mold cavity, and the protrusion is adapted to penetrate the anti-corrosion sheet.

[0014] Preferably, in step S400, the post-processing process includes sandblasting and polishing the area near the patching of the mold cavity to remove marks.

[0015] Compared with the prior art, the beneficial effects of this application are:

[0016] The present invention pre-grinds and flattens the convex points on the spark pattern surface, then performs patching on the convex points, and finally performs post-processing on the patched convex points, so that the convex points can form a texture that matches the original spark pattern surface after being processed, making the processing of the convex points more natural and not causing damage to the spark pattern surface of the mold cavity. In addition, through the patching process, it can be ensured that the texture on the convex points matches the texture of the spark pattern surface, thereby achieving a more beautiful and consistent appearance effect on the molded product, and the method greatly improves the appearance quality of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the spark pattern surface structure in the existing mold cavity.

[0018] Figure 2 It is a schematic diagram of the convex points on the spark pattern surface of the present invention and the convex points after being polished.

[0019] Figure 3It is a schematic diagram of the convex points on the spark pattern surface of the present invention after being processed by manual electric spark and adding corrosion solution.

[0020] Figure 4 It is a linear relationship between the reaction time of the etching solution of the present invention to the bump and the thickness of the bump consumed.

[0021] Figure 5 It is a schematic diagram of the working principle of the present invention.

[0022] In the figure: 1. mold body; 101. mold cavity; 2. spark pattern surface; 3. convex point; 4. etching; 5. etching solution. DETAILED DESCRIPTION

[0023] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0024] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present application.

[0025] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0026] In the prior art, mold spark pattern is a product surface treatment process, the purpose of which is to enhance the appearance and texture of plastic parts, so that the product presents a variety of changes or a brand-new design. It should be noted that the processing of the spark pattern surface 2 acts on the mold cavity 101 rather than directly performing surface processing on the product. The principle is: the discharge is to generate an electric field by moving the electrode infinitely close to the mold. Under the action of spark oil, the electrical energy is converted into heat energy to slowly peel off the electrons at the mold processing site to achieve the processed cavity effect. In the process of spark pattern processing, the following problems will arise:

[0027] The formation of bump 3 in EDM: (1) Incomplete removal of metal particles: During the discharge process, the metal particles between the electrode and the workpiece are not completely removed by the machining fluid, resulting in the inability to completely eliminate the ionization state. When the next discharge begins, the instantaneous high temperature will form a bump 3 on the workpiece surface. (2) The role of spark oil: Spark oil acts as a medium to form a discharge channel between the electrode and the workpiece and helps to dissipate heat energy. If the spark oil is used improperly or flushed poorly, it may cause carbon deposits and the formation of bumps 3. (3) Discharge parameter setting: Improper setting of the discharge time and rest time, or excessive servo adjustment, may lead to unstable processing and the formation of bumps 3. (4) Insufficient tool lift height: During EDM, if the tool lift height is not enough, the carbon slag cannot be discharged smoothly, which may also lead to carbon deposits and bumps 3.

[0028] Therefore, the inventor of the present application has developed a method for processing mold spark pattern, one implementation of which is as follows: Figures 1 to 5 As shown, the following steps are included:

[0029] S100 : performing electrical spark machining in the mold cavity 101 of the mold body 1 , thereby generating a spark pattern surface 2 in the mold cavity 101 , and convex points 3 appear on the spark pattern surface 2 .

[0030] S200: grinding and polishing the convex point 3 to remove part of the convex point 3.

[0031] S300: performing a pattern filling process on the polished convex point 3. It can be understood that the pattern filling process is to form a texture on the convex point 3 that matches the spark pattern surface 2. The texture is close to the spark pattern surface 2.

[0032] S400: Post-processing the mold cavity 101 after the patching: making the above-mentioned texture and the spark pattern surface 2 transition, so that the two are matched more naturally and smoothly.

[0033] It can be seen that by pre-grinding and flattening the convex point 3, then performing patching on the convex point 3, and finally performing post-processing on the patched convex point 3, the convex point 3 can be processed and still form a texture that matches the original spark pattern surface 2, making the processing of the convex point 3 more natural and not causing damage to the spark pattern surface 2 of the mold cavity 101. In addition, through the patching process, it can be ensured that the texture on the convex point 3 matches the texture of the spark pattern surface 2, thereby achieving a more beautiful and consistent appearance effect on the molded product, and this method greatly improves the appearance quality of the product.

[0034] Of course, when performing EDM in the mold cavity 101, the defect of convex point 3 generally occurs, but depression may also occur. The reasons for its formation are: (1) Discharge gap: The size of the discharge gap affects the degree of energy concentration. A gap that is too small may cause local overheating and melting, forming a depression. (2) Working fluid: The type and state of the working fluid will also affect the processing results. For example, a medium with low viscosity and high flash point helps to reduce the formation of pits. (3) Processing parameters: Including parameters such as peak current and pulse width. Improper parameter settings may cause the surface roughness to deteriorate, thereby forming a depression. (4) Mechanical factors: Such as the accuracy of the guide wheel and bearing, the constancy of the tension during up and down movement, etc. These factors may cause the electrode movement trajectory to be inconsistent, affecting the processing accuracy. (5) Processing parameters: Including parameters such as peak current and pulse width. Improper parameter settings may cause the surface roughness to deteriorate, thereby forming a depression.

[0035] Therefore, in order to solve the above technical problems, in one embodiment of the present application, in step S200, before the flattening treatment of the convex point 3 is performed, the concave part can be filled to form the above convex point 3. It should be known that the filled convex point 3 here and the convex point 3 during the above-mentioned electric discharge pattern processing are actually formed in a different way, but we can regard them as convex points 3 on the spark pattern surface 2, and then perform the same subsequent treatment on the convex point 3.

[0036] Specifically, when there is a depression on the spark pattern surface 2, it means that a small part is missing inside the mold cavity 101. At this time, we can fill the depression with molten metal. When the metal liquid cools and solidifies, it will form a convex point 3 on the spark pattern surface 2. Of course, the choice of filling material should be compatible with the material of the mold cavity 101 to ensure that the filled convex point 3 will not be mismatched or fall off during subsequent processing and use. The filling material can be a metal alloy that is the same or similar to the mold cavity 101 to ensure that its thermal expansion coefficient and mechanical properties match those of the mold body 1.

[0037] As a further description of the above embodiment, in step S200 , in order to prevent damage to the spark pattern surface 2 when machining the convex point 3 , the height of the convex point 3 after polishing should be greater than or equal to the height of the spark pattern surface 2 .

[0038] Specifically, Figure 2 As shown in (A), there are convex points 3 on the spark pattern surface 2; after grinding and polishing, as shown in Figure 2As shown in (B), the height of the convex point 3 is still greater than the height of the spark pattern surface 2. It should be known that the height after polishing is ideally flush with the height of the spark pattern surface 2, but in actual operation, it is difficult to make the two flush. Therefore, in order to ensure the integrity and aesthetics of the spark pattern surface 2, the height of the convex point 3 after polishing should be slightly higher than the height of the spark pattern surface 2, so that in the subsequent patching process, it can be easier to match the texture on the convex point 3 with the texture of the spark pattern surface 2 to achieve a smooth transition effect.

[0039] In one embodiment of the present application, in step S300, the patching process includes the following steps:

[0040] (1) If Figure 3 As shown, the polished convex point 3 is subjected to electric spark treatment again, but since the range of the convex point 3 is small, it is not convenient to process it by electric spark equipment at this time. Then the convex point 3 can be processed by hand, specifically using a small electrode for local processing, so that spark patterns are formed on the convex point 3. Of course, at this time, the spark patterns on the convex point 3 and the spark pattern surface 2 in the mold cavity 101 may not be well connected and transitioned.

[0041] (2) If Figure 4 As shown, the convex point 3 after the electric spark treatment is etched by the etching solution 5 (i.e., the leather grain solution). It should be known that the solution will flow along the spark grain on the convex point 3 under the action of gravity, so the spark grain will be corroded by the solution, and then the spark grain will be further deepened and extended, and then the etched grain 4 can be well matched with the original spark grain surface 2.

[0042] Specifically, the etching solution 5 includes, by weight, 10-15 parts of nitric acid, 10-15 parts of sulfuric acid, 10-15 parts of hydrochloric acid, 5-12 parts of hydrofluoric acid, 5-10 parts of cupric chloride, 1-5 parts of surfactant, and 80-140 parts of deionized water. The etching solution 5 has a strong corrosive nitric acid solution, a sulfuric acid solution, a hydrofluoric acid solution, and a hydrochloric acid solution as main components, which can clearly and effectively corrode the bump 3, and cupric chloride (of course, ferric chloride, zinc chloride and other solutions can also be used) can make the Cr, Fe and other elements in the bump 3 (generally made of steel) preferentially desolvated, and chloride ions have a significant effect on the corrosion of metals, which is conducive to improving the corrosion efficiency of the etching solution 5. Of course, since the corrosive solution 5 is generally added and controlled manually, the time required for the corrosion of the corrosive solution 5 must give the staff time to react. Therefore, the use of surfactants can slow down the corrosion rate to avoid excessive corrosion affecting the corrosion effect. At the same time, it can also give the staff a reaction space to prevent the corrosive solution 5 from flowing into the spark pattern surface 2 and causing excessive corrosion. The surfactant can be sodium dodecylbenzene sulfonate and / or sodium dodecyl sulfate.

[0043] like Figure 5 As shown, after adding an appropriate amount (for example, 0.2ml-2ml) of the etching solution 5 into the bump 3, the time and the thickness of the corrosion of the bump 3 are varied. Specifically, after adding the etching solution 5, the corrosion of the bump 3 will increase, and the two are in a proportional relationship as a whole. In other words, as the time the solution exists gets longer and longer, more and more parts of the bump 3 will be corroded, and the corrosion thickness of the bump 3 will gradually increase. According to the experimental data, there is a certain linear relationship between the corrosion time t and the corrosion thickness T of the bump 3, which provides a basis for controlling the corrosion depth. In actual operation, the staff can refer to the time and thickness variation table to determine the specific time for the corrosion solution 5 to act according to the corrosion depth to be achieved.

[0044] Specifically, since the bump 3 has been subjected to manual electric sparking to generate spark patterns before corrosion, the bump 3 will be in full contact with the corrosion solution 5, and then the corrosion solution 5 will etch the bump 3 at a very fast rate. In theory, the longer the time, the greater the corrosion thickness; but as the corrosion solution 5 is consumed, the corrosion effect gradually becomes worse. At the same time, we need to consider the following problem: under the action of gravity, part of the corrosion solution 5 will also enter the spark pattern surface 2 on the mold cavity 101. Therefore, in order to reduce the corrosion of the original spark pattern surface 2, the corrosion time can be controlled to be after 3-8 seconds.

[0045] Further, such as Figure 5As shown, within 5 seconds, the corrosion thickness will be proportional to the time, and the growth rate is the largest at this time, and it will not cause significant corrosion to the original spark pattern surface 2. Therefore, the corrosion time is preferably 5 seconds, which can ensure that the etching pattern on the convex point 3 and the texture of the spark pattern surface 2 can be smoothly connected, while avoiding unnecessary damage to the spark pattern surface 2. After the corrosion is completed, the convex point 3 should be immediately rinsed with clean water to remove the residual corrosion solution 5 to prevent further corrosion.

[0046] Based on the above embodiment, the following problem may occur in the specific etching process: the reserved height of the convex point 3 after grinding and flattening is too high, which causes the height of the convex point 3 after etching to be still greater than the height of the spark pattern surface 2. Therefore, in the etching process of the convex point, the etching process can be repeated again, that is, the etching solution 5 is added to the convex point 3 again, so that the convex point 3 is etched shorter again, until the height of the convex point 3 is less than or equal to the height of the spark pattern surface 2, so as to achieve a smooth transition with the spark pattern surface 2.

[0047] In this embodiment, in order to further reduce the excessive impact of the corrosive solution 5 on the spark pattern surface 2 when the bumps 3 are added, an anti-corrosion (corrosion-resistant) sheet can be provided in the mold cavity 101. Of course, a through groove is provided on the anti-corrosion sheet, and the bumps 3 can pass through the through groove. In other words, the anti-corrosion sheet is fitted in the mold cavity 101. In this way, when the corrosive solution 5 is added, it can be prevented from splashing onto the spark pattern surface 2, thereby avoiding unnecessary corrosion to the spark pattern surface 2.

[0048] It should be noted that no matter what measures are adopted, the corrosive solution 5 will inevitably enter the spark pattern surface 2, but the corrosive solution 5 that enters the spark pattern surface 2 is a small amount, and the corrosive solution 5 will also flow along the texture of the spark pattern surface 2, so that the corrosive solution 5 is dispersed. Therefore, the corrosion of the inner wall of the spark pattern surface 2 is very small and can be ignored, and it is difficult to detect with the naked eye after the subsequent product is formed.

[0049] In this embodiment, in step S400, the post-processing process is: performing a sandblasting polishing process on the mold cavity 101,

[0050] To remove the residues and tiny burrs on the inner surface of the etched pattern 4 and the spark pattern surface 2. The main purpose is to process the vicinity of the original convex point 3, so that the etched texture and the spark pattern surface 2 are transitioned, making the spark pattern surface 2 of the entire mold cavity 101 smoother and improving the molding quality of the product.

[0051] The working method of the present invention is (such as Figure 5 shown):

[0052] S100 : performing electrical spark machining in the mold cavity 101 of the mold body 1 , thereby generating a spark pattern surface 2 in the mold cavity 101 , on which convex points 3 and concavities appear.

[0053] S200: For the depression, the molten metal liquid can be filled in the depression, and when the metal liquid is cooled and solidified, a convex point 3 located on the spark pattern surface 2 is formed. Then, the convex point 3 is polished and leveled, so that part of the convex point 3 is removed, but the height of the convex point 3 is still higher than the spark pattern surface 2.

[0054] S300: Manual electric spark treatment is performed on the convex point 3, so that spark patterns are formed on the convex point 3, and then a corrosive solution 5 is added to the convex point 3, so that the spark patterns will be corroded by the solution, and then the spark patterns are further deepened and extended, and then an etched (engraved) pattern is obtained; of course, the corrosive solution 5 will also enter the spark pattern surface 2, and at this time, the etched pattern 4 can be well matched with the original spark pattern surface 2, so as to achieve a smooth transition effect, so that the convex point 3 and the depression on the overall spark pattern surface 2 are removed and more naturally, and the etching time is preferably set to 5 seconds, and then the convex point 3 should be immediately rinsed with clean water to remove the residual corrosive solution 5. Of course, during etching, if the height of the convex point 3 is still greater than the height of the spark pattern surface 2, the corrosion etching process can be repeated again, that is, the corrosive solution 5 is added to the convex point 3 again, so that the convex point 3 is etched shorter again, until the height of the convex point 3 is less than or equal to the height of the spark pattern surface 2, so as to achieve a smooth transition with the spark pattern surface 2.

[0055] S400: performing sandblasting and polishing treatment on the mold cavity 101 to make the spark pattern surface 2 of the entire mold cavity 101 smoother, thereby improving the molding quality of the product.

[0056] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A method for processing mold fire patterns, characterized in that: The steps include: S100: The mold cavity is subjected to electrospark machining to obtain a spark pattern surface, on which convex points will appear; S200: polishing the convex points on the spark pattern surface; the height of the convex points after polishing is greater than the height of the spark pattern surface; S300: performing a pattern filling process on the polished convex point to match it with the spark pattern surface; the pattern filling process comprises the following steps: firstly performing a manual electric spark process on the convex point, and then etching the convex point with a corrosive solution to obtain a pattern, so that the pattern and the spark pattern surface are matched; S400: performing post-processing on the mold cavity after the patching, wherein the post-processing process includes performing sandblasting and polishing to remove marks near the patching of the mold cavity.

2. The method for mold fire pattern processing according to claim 1, characterized in that: In step S200, before the polishing process is performed, the following steps are also included: the depressions of the spark pattern surface are filled to form new convex points.

3. The method for mold fire pattern processing according to claim 1, characterized in that: The etching solution comprises, by weight, 10-15 parts of nitric acid, 10-15 parts of sulfuric acid, 10-15 parts of hydrochloric acid, 5-12 parts of hydrofluoric acid, 5-10 parts of cupric chloride, 1-5 parts of a surfactant, and 80-140 parts of deionized water.

4. The method for mold fire pattern processing according to claim 3, characterized in that: The etching time of the convex point by the etching solution is 3-8 seconds.

5. The method for mold fire pattern processing according to claim 4, characterized in that: The etching time of the convex point by the etching solution is 5 seconds.

6. The method for mold fire pattern processing according to claim 1, characterized in that: During the etching process of the convex point: if the height of the convex point is greater than the height of the spark pattern surface, the etching process is repeated until the height of the convex point is less than or equal to the height of the spark pattern surface.

7. The method for mold fire pattern processing according to claim 1, characterized in that: In step S300, an anti-corrosion sheet is arranged in the mold cavity, and the protrusion is adapted to penetrate the anti-corrosion sheet.

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