Breathable metal mold and method for manufacturing the same

Abstract

The application relates to a breathable metal mold which is composed of a plurality of mutually laminated deposition layers, the material of the deposition layers is metal powder and a chemical adhesive, and at least one surface of the deposition layers is provided with at least one groove. The application is composed of a plurality of mutually laminated deposition layers, and the surface of the deposition layers is provided with the groove, the groove plays the role of an airflow channel between adjacent deposition layers, can effectively increase the hole interconnection degree of the metal mold, and makes the breathability of the breathable metal mold better.

Description

Technical Field

[0001] This application relates to the field of molds, and more particularly to permeable metal molds. Background Technology

[0002] By utilizing the fact that the mean free path of gas molecules is smaller than that of pores, permeable metal molds allow gas to escape smoothly and promptly from trapped areas during the production process, avoiding gas trapping problems in injection molding and improving the quality and yield of injection molded products. Good permeability can improve the pressure difference between the inside and outside of the mold cavity, increase mold opening efficiency, reduce demolding losses, and help reduce energy consumption, defects, optimize mold structure, and improve production efficiency. To achieve the above objectives, an ideal permeable metal mold needs to have a large number of interconnected micropores evenly distributed inside.

[0003] Currently, the processing methods for permeable metal molds mainly employ powder metallurgy and selective laser melting additive manufacturing. These technologies present varying degrees of technical challenges in manufacturing permeable metal molds, as the resulting pores cannot achieve a complex spatial distribution. Powder metallurgy, by controlling the average particle size, loading rate, and loose density of the powder, and adding a certain proportion of foaming agent, introduces numerous pore defects during sintering to prepare sintered metal samples with micropores. However, this method produces pores with low interconnectivity and random, irregular pore distribution, making it difficult to further improve permeability. Summary of the Invention

[0004] This application provides a breathable metal mold and its preparation method to solve the technical problem of low interconnection degree of holes in existing breathable metal molds.

[0005] In a first aspect, embodiments of this application provide a breathable metal mold, which is composed of a plurality of stacked deposition layers. The material of the deposition layers includes metal powder and chemical binder, and at least one channel is provided on the surface of at least one deposition layer.

[0006] In some embodiments of this application, the particle size of the metal powder is no greater than 45 μm.

[0007] In some embodiments of this application, the width of the channel is 30-1000 μm.

[0008] In some embodiments of this application, the thickness of the deposited layer is 0.05-2.0 mm.

[0009] In some embodiments of this application, the metal powder is stainless steel powder.

[0010] Secondly, embodiments of this application provide a method for preparing a breathable metal mold, the method comprising the following steps:

[0011] Using a mixture of metal powder and chemical binder as raw material, deposition lines are prepared by 3D printing according to a preset deposition path, so that multiple deposition lines form a deposition layer;

[0012] The laser is used to process the printed deposition lines, evaporating the chemical binder at the processing point, causing the metal powder to collapse and form channels;

[0013] Several stacked deposition layers are prepared through the above steps to form a green body;

[0014] The green body is degreased and sintered to obtain the breathable metal mold.

[0015] In some embodiments of this application, the diameter of the printhead used for printing is 0.15-2 mm, the temperature of the printhead during printing is 80-240°C, and the printing speed is 1-100 mm / s.

[0016] In some embodiments of this application, the laser is provided by a laser, which is an ultraviolet laser or an infrared laser.

[0017] In some embodiments of this application, the power of the laser is 10-100W, the diameter of the focused spot of the laser is 30-1000μm, and the laser operates in pulsed or continuous mode.

[0018] In some embodiments of this application, the degreasing is at least one of solvent degreasing, thermal degreasing, and catalytic degreasing, and the peak temperature of the sintering is higher than 70% of the melting point of the metal powder.

[0019] The technical solutions provided in this application have the following advantages compared with the prior art:

[0020] The breathable metal mold provided in this application is composed of several stacked deposition layers, and the surface of the deposition layers is provided with channels. The channels act as airflow channels between adjacent deposition layers, which can effectively increase the interconnection of the holes in the metal mold and make the breathable metal mold more breathable. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the structure of the deposition layer provided in an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the structure of the breathable metal mold provided in Embodiment 1 of this application;

[0025] Figure 3 This is a schematic diagram of the structure of the breathable metal mold provided in Embodiment 2 of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] Unless otherwise specified, the terminology used herein should be understood as having the meaning as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any conflict, this specification shall prevail.

[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0029] Existing breathable metal molds suffer from the technical problem of low interconnection of pores.

[0030] The technical solution provided in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0031] Firstly, this application provides a breathable metal mold, please refer to... Figures 1-3 The breathable metal mold is composed of several stacked deposition layers 1. The material of the deposition layer 1 includes metal powder and chemical binder. At least one channel 2 is provided on the surface of at least one deposition layer 1.

[0032] The purpose of setting the structure of the breathable metal mold as a multi-layer deposition layer 1 is to facilitate the processing of channels 2 on the surface of each deposition layer 1 after the formation of each deposition layer 1.

[0033] The deposition layer 1 described in this application can be formed in a manner commonly used in the art, such as 3D printing, spraying, or roller coating.

[0034] The channel 2 described in this application can be formed in a manner commonly used in the art, such as machining, laser processing, or chemical etching.

[0035] Both the metal powder and the chemical binder described in this application can be selected from conventional breathable metal mold raw materials.

[0036] In some embodiments, channels 2 are provided on the surface of all deposited layers 1 except the uppermost layer.

[0037] The breathable metal mold provided in this application is composed of several stacked deposition layers 1, and the surface of the deposition layer 1 is provided with channels 2. The channels 2 act as airflow channels between adjacent deposition layers 1, which can effectively increase the interconnection degree of the holes in the metal mold and make the breathable metal mold more breathable.

[0038] In some embodiments of this application, the particle size of the metal powder is no greater than 45 μm.

[0039] The advantages of using the above-mentioned particle size for the metal powder are that, on the one hand, the gap size between the metal powders is moderate, which is suitable for injection molding, and it can also achieve a good air permeability when combined with the channel 2; on the other hand, this particle size is suitable for 3D printing.

[0040] In some embodiments of this application, the width of the channel 2 is 30-1000 μm.

[0041] In some embodiments of this application, the thickness of the deposition layer 1 is 0.05-2.0 mm.

[0042] In some embodiments of this application, the metal powder is stainless steel powder.

[0043] Secondly, embodiments of this application provide a method for preparing a breathable metal mold, the method comprising the following steps:

[0044] S1: Using a mixture of metal powder and chemical binder as raw material, deposition lines are prepared by 3D printing according to a preset deposition path, so that multiple deposition lines form a deposition layer 1;

[0045] S2: Use a laser to process the printed deposition line, evaporate the chemical binder at the processing point, and cause the metal powder to collapse to form a channel 2;

[0046] S3: Several stacked deposition layers 1 are prepared through the above steps to form a green body;

[0047] S4: Degrease and sinter the green blank to obtain the breathable metal mold.

[0048] This application uses 3D printing as the preparation method, which is less difficult and less costly than existing technologies.

[0049] In practice, 3D printing is achieved through a nozzle, and the laser is emitted by a laser generator. While the nozzle prints the deposition line along a predetermined path, the laser can delay for a period of time and then perform laser processing on the deposition line along the predetermined path. Since the movement paths of the nozzle and the laser are the same, the mechanical principle of the device, which includes the nozzle and the laser, for implementing the method described in this application is relatively simple and the implementation difficulty is low.

[0050] It is easy to understand that the predetermined path is a conventional setting for 3D printing. The principle of 3D printing is to make the nozzle move along the preset path and continuously print linear materials. As printing progresses, the linear materials gradually combine into planar materials.

[0051] As an example, the preset path described in this application can be a reciprocating path; please refer to [reference needed]. Figures 1-3 When the nozzles move in parallel directions during printing of adjacent deposition layers 1, the resulting permeable metal mold is as follows: Figure 2 When the nozzle movement directions are perpendicular to each other during printing of adjacent deposition layers 1, the resulting permeable metal mold is as follows: Figure 3 .

[0052] It should be noted that Figure 1 and Figure 2 The examples provided are merely illustrative of the embodiments described in this application and do not represent any limitation. For instance, the nozzle movement direction of adjacent deposition layers 1 does not necessarily have to be perpendicular or parallel, but can be any other angle; the predetermined path described in this application is not limited to a reciprocating path, and all conventional 3D printing solutions are applicable to this application.

[0053] The working principle of the laser is that the laser performs dynamic selective heat treatment on the deposited layer 1 according to the scanning path. The surface binder is removed by the laser heating action, and the surface metal powder collapses downward due to the lack of binder to form the corresponding channel 2.

[0054] Degreasing and sintering are routine steps in the field of breathable metal molds, and those skilled in the art can perform degreasing and sintering based on common knowledge.

[0055] The breathable metal mold prepared by the method described in this application is a type of breathable metal mold as described in the first aspect. Therefore, the method for preparing the breathable metal mold described in this application possesses all the beneficial effects described in the first aspect, which will not be elaborated further here.

[0056] In some embodiments of this application, the diameter of the printhead used for printing is 0.15-2 mm, the temperature of the printhead during printing is 80-240°C, and the printing speed is 1-100 mm / s.

[0057] In some embodiments of this application, the laser is provided by a laser, which is an ultraviolet laser or an infrared laser.

[0058] In some embodiments of this application, the power of the laser is 10-100W, the diameter of the focused spot of the laser is 30-1000μm, and the laser operates in pulsed or continuous mode.

[0059] It should be noted that although forming channels on 3D-printed layers using lasers is a conventional method in the art, the method described in this application differs from conventional methods in that the purpose of laser processing in this application is to evaporate the chemical binder, rather than ablate the 3D-printed material itself. The advantage is that this invention can be implemented using a lower-power, simpler-structured laser. Typically, laser processing for ablating 3D-printed materials requires several kilowatts of power, while this application only requires 10-100W, a reduction of one to two orders of magnitude. This lowers both the laser purchase cost and energy consumption cost, and the simpler laser structure also makes installation easier.

[0060] In some embodiments of this application, the degreasing is at least one of solvent degreasing, thermal degreasing, and catalytic degreasing, and the peak temperature of the sintering is higher than 70% of the melting point of the metal powder.

[0061] In some embodiments of this application, the chemical adhesive is at least one of paraffin wax and polyethylene.

[0062] The present application is further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to national standards. If there is no corresponding national standard, then general international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0063] Example 1

[0064] H13 steel powder with a maximum particle size of 15μm was selected, and the powder loading rate was 50%. The powder and paraffin were mixed at high temperature to make printing raw material.

[0065] A 0.6mm diameter nozzle was selected for 3D printing. The preset layer thickness was 0.25mm, the preset printing speed was 20mm / s, the preset printing spacing was 0.6mm, and the preset nozzle temperature was 80℃. During the printing process, the nozzle reciprocated. When printing adjacent deposition layers 1, the nozzle movement directions were parallel to each other.

[0066] The laser is a continuous ultraviolet laser that reciprocates following the nozzle. The laser output power is set to 20W, and the spot diameter is 150μm, centered on the deposition lines produced by the printing process. The initial focus of the laser is set on the printing bed, rising 0.25mm after each layer is printed. The part model is 3D sliced, and the printing material fill pattern uses a concentric circle line filling method with a constant interlayer phase angle. 3D printing begins simultaneously, with the laser starting to operate until the green sample is printed. The green sample is then solvent-degreased, thermally degreased, and sintered to obtain the desired result. Figure 2 The permeable metal mold shown.

[0067] Example 2

[0068] 316L stainless steel powder with a maximum particle size of 45μm and a powder loading rate of 40% was selected. The powder was then mixed with paraffin and polyethylene at high temperature to make printing raw material.

[0069] A 1.0mm diameter nozzle was selected for 3D printing. The preset layer thickness was 0.4mm, the preset printing speed was 40mm / s, the preset printing spacing was 1.0mm, and the preset nozzle temperature was 220℃. During the printing process, the nozzle reciprocated. The nozzle movement directions were perpendicular to each other when printing adjacent deposition layers 1.

[0070] The laser is a pulsed infrared laser. The output power of the laser on the nozzle off-axis is set to 30W, the spot diameter to 300μm, and the processing frequency to 50Hz. The initial focus of the laser is set on the printing bed, and it is raised 0.4mm after each layer is printed. The part model is 3D sliced, and the printing material fill pattern adopts a reciprocating line fill method with an interlayer phase angle of 90°. 3D printing begins, and the laser starts working simultaneously until the green sample is printed. The green sample is then solvent-degreased, thermally degreased, and sintered to obtain the desired result. Figure 3 The permeable metal mold shown.

[0071] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0072] In this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Furthermore, in the description of this application, the terms "comprising," "including," etc., mean "including but not limited to." Moreover, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In this document, "and / or" describes the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent: A alone, A and B simultaneously, or B alone. For associations involving three or more related objects described using "and / or", it indicates that any one of the three related objects can exist alone, or at least two of them can exist simultaneously. For example, for A, and / or B, and / or C, it can mean that any one of A, B, and C exists alone, or any two of them exist simultaneously, or all three of them exist simultaneously. In this document, "at least one" means one or more, and "more than one" means two or more. "At least one", "at least one of the following", or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can each be single or multiple.

[0073] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A breathable metal mold, characterized in that, The breathable metal mold is composed of several stacked deposition layers. The material of the deposition layers includes metal powder and chemical binder. At least one channel is provided on the surface of at least one deposition layer. The channel is formed by laser evaporation of the chemical binder on the surface of the deposition layer, causing the metal powder at that location to collapse. The width of the channel is 30-1000 μm. The thickness of the deposition layer is 0.05-2.0 mm.

2. The breathable metal mold according to claim 1, characterized in that, The particle size of the metal powder is no greater than 45 μm.

3. The breathable metal mold according to claim 1, characterized in that, The metal powder is stainless steel powder; and / or... The chemical adhesive is at least one of paraffin wax and polyethylene.

4. A method for preparing a breathable metal mold according to any one of claims 1-3, characterized in that, The method includes the following steps: Using a mixture of metal powder and chemical binder as raw material, deposition lines are prepared by 3D printing according to a preset deposition path, so that multiple deposition lines form a deposition layer; The laser is used to process the printed deposition lines, evaporating the chemical binder at the processing point, causing the metal powder to collapse and form channels; Several stacked deposition layers are prepared through the above steps to form a green body; The green body is degreased and sintered to obtain the breathable metal mold.

5. The method for preparing a breathable metal mold according to claim 4, characterized in that, The diameter of the printhead used for printing is 0.15-2mm, the temperature of the printhead during printing is 80-240℃, and the printing speed is 1-100mm / s.

6. The method for preparing a breathable metal mold according to claim 4, characterized in that, The laser is provided by a laser, which is either an ultraviolet laser or an infrared laser.

7. The method for preparing a breathable metal mold according to claim 6, characterized in that, The laser has a power of 10~100W, a focused spot diameter of 30-1000μm, and operates in pulsed or continuous mode.

8. The method for preparing a breathable metal mold according to claim 4, characterized in that, The degreasing is at least one of solvent degreasing, thermal degreasing, and catalytic degreasing, and the peak temperature of the sintering is higher than 70% of the melting point of the metal powder.

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