A casting plastic mold, a mold system and process combining 3D printing technology

Abstract

This invention relates to a casting plastic mold, a mold system and process incorporating 3D printing technology, primarily targeting casting mold systems and processes for plastic products with uneven wall thicknesses using 3D printing. The mold core of this invention mainly consists of a stress-bearing surface distributed on the surface of the mold core and an internal mold core filling structure. The mold core filling structure can employ various network topologies, with gaps forming interconnected spaces. Therefore, although the actual effects produced by using different topologies may vary slightly, the core principle is that the network structure increases the surface area by a hundredfold, thereby achieving a rapid heat dissipation effect (whether through water contact or natural heat dissipation, the efficiency is 10-15 times that of the original mold). The invention also provides its manufacturing process and the mold system it constitutes. This can reduce mold weight by 20%, increase molding efficiency for thick plastic products by over 100%, and accelerate the production cycle.

Description

Technical Field

[0001] This invention relates to the field of molds, and in particular to a mold for plastic products with uneven wall thickness, and a casting mold system and process combining 3D printing technology. Background Technology

[0002] Injection molding has been around for nearly a century. Compared to other processing technologies, it is a relatively young industry, with many processes and methods still in their infancy. As a result, we have found many problems with unstable and inefficient final product production due to design, manufacturing, and molding processes when using this technology.

[0003] Because problems at any stage of injection molding production can lead to defects, the injection molding process is often referred to in the industry as a "project of eternal regret." Its technical defects will eventually manifest in the actual production process. Since we are in the mortise and tenon industry, mortise and tenon itself is a subtractive processing method, which has produced a large number of sophisticated and reliable connection technologies. However, injection molding production is an additive processing method, so subtractive and additive processing often face various contradictions.

[0004] These problems are common to all parts that require injection molding, so the design of injection molded parts generally needs to take into account wall thickness, weight, lifespan, structure and surface.

[0005] Uneven wall thickness can cause product shrinkage, resulting in loss of appearance, size, and functionality; unreasonable weight can prevent the product from being produced fully, resulting in structural defects; neglecting the lifespan can lead to product damage after repeated use, resulting in excessive waste; unreasonable structure can exponentially increase the price of molds and the difficulty of processing, resulting in loss of economic benefits; and an imperfect surface can fundamentally cause users to develop resistance, affecting the use and sale of the product.

[0006] In addition, there is an even more important problem in the mortise and tenon industry. Since mortise and tenon is a subtractive manufacturing method, it has produced a large number of sophisticated and reliable connection technologies. However, injection molding is an additive manufacturing process. Therefore, subtractive and additive manufacturing often face various contradictions.

[0007] For these reasons, due to the special nature of the inventor's industry and products, it is necessary to change this situation through technology and innovation. The primary goal is to ensure their own economic interests, and the secondary goal is to bring a new perspective and solution to society, thereby reducing the waste brought about by social production.

[0008] In the production and R&D process, the first problem we faced was that the wall thickness did not meet the injection molding conditions. There are many structural features in mortise and tenon joints that cannot guarantee uniform wall thickness. Therefore, large-scale deformation and shrinkage after production will cause the mortise and tenon products to be unable to fit together effectively. However, for the needs of mortise and tenon culture, we have to bite the bullet and produce them. After countless attempts, the inventor discovered various patterns. Therefore, the primary purpose of this invention is to solve the problem of reasonable production of products with uneven wall thickness.

[0009] Secondly, there is the issue of structure and lifespan. Only by ensuring that the mold has a long lifespan can injection molding production demonstrate its unique advantages. As we all know, mortise and tenon structures often involve many complex structures. These complex structures face numerous difficulties in subtractive manufacturing, let alone when we need to use additive manufacturing methods. Therefore, structure and lifespan have become the second key issues that need to be addressed in this invention.

[0010] Finally, there is the production issue. The mold manufacturing and processing cycle generally requires 30-50 working days, which is a disruptive pace in modern life. Often, three months is the key to whether a product can seize the market opportunity and successfully reap the rewards and develop positively. Moreover, there are many "non-reducible" processes in the mold manufacturing and processing cycle. Therefore, reducing the number of processes is another problem that this invention aims to solve.

[0011] Furthermore, during the development of this invention, in order to improve the accuracy of the mold, the introduction of 3D printing technology was considered. Several patents for 3D printed molds were found through searching. However, it was discovered that they only remained at the theoretical level and lacked actual production experience. For example, the consumables used for printing mentioned in the existing patents are actually common materials for metal 3D printing, which are not only not innovative but also not feasible. The processing flow is simply replacing one of the original machining steps—mold core subtraction machining—with 3D printing. After testing, this method is not economically efficient and cannot achieve the production efficiency of machining at all. This is because the actual production efficiency and quality of metal 3D printing are far lower than those of machining. For example, the original general mold core parts can be finely carved by CNC machine tools in 8-12 hours, with a cost of about 4,000-6,000 yuan. However, 3D metal printed parts of the same size require 24-48 hours of printing and 48-72 hours of proprietary 3D printing post-processing, with a cost of about 20,000-25,000 yuan and a processing accuracy far lower than that of machining. Therefore, the existing technology cannot be directly applied to this field.

[0012] Furthermore, regardless of whether 3D printing brings economic benefits, the feasibility of using 3D printing for rough processing followed by machining for fine processing involves the issue of material strength. As we all know, the theoretical basis of metal 3D printing is laser welding. During the welding process, a large number of dense gaps will inevitably be generated between the materials. These dense gaps will cause the machined product to break apart, thus losing strength and precision, and therefore have no reference value.

[0013] 3D printing is currently widely used in various mechanical fields. Based on the current processing technology and forms, it can be inferred that it will not be able to completely replace traditional processing techniques for decades, unless there is innovation in materials and a completely new printing method. However, with the current known technical solutions, no such technology has yet emerged.

[0014] Therefore, this invention first innovates and improves the 3D process method based on practice to realize the 3D printing of mold cores. Secondly, it explores a brand-new rapid prototyping solution that combines 3D printing with traditional processes. Learning from practice is the theoretical basis of this invention. Summary of the Invention

[0015] To address the above problems, the main technical problem solved by this invention is to provide a casting mold system, process, and mold structure that combines 3D printing technology for plastic products with uneven wall thickness, which is simple in structure, low in cost, and easy to operate.

[0016] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0017] A casting plastic mold is disclosed. The mold core is mainly composed of force-bearing surfaces distributed on the surface of the mold core and an internal structure with a network topology. The network topology is formed by stacking several cubic units. Each cubic unit consists of a mesh support composed of several endpoints and connecting rods between the endpoints. The gaps between the connecting rods in the network topology form interconnected spaces. This invention, utilizing the aforementioned mesh support, can enhance heat dissipation efficiency and provide sufficiently high strength. Furthermore, it can be combined with 3D printing technology and lost-wax precision casting to provide a new manufacturing process. Various network topologies can be obtained through digital model calculations to meet diverse performance requirements.

[0018] Furthermore, the force-bearing surface is preferably located on a node of the cube that is in contact with it.

[0019] Furthermore, the area within the frame formed by the twelve borders of the cube is the topological structure design region, and the contact surfaces of the cube are point-to-point fitted, meaning that the endpoints of the corresponding mating surfaces of any two units coincide. Moreover, the eight points of the quadrilateral of the contact surface can be designed to be fluidly adjusted according to the shape of the mold core, thereby allowing it to fit the external shape of the mold core. Simultaneously, thanks to the above structure, this invention differs from the mold steel commonly used in existing technologies. This invention uses a mold produced by die casting from cast iron, aluminum, or titanium alloy materials. This reduces material costs and processing difficulty, and allows for the use of precision casting technology, thereby improving accuracy. This makes it suitable for fields such as the mortise and tenon industry, where high precision requirements and uneven wall thickness exist.

[0020] The present invention also provides a casting plastic mold manufacturing process that combines 3D printing technology with the above-mentioned mold, wherein the plastic mold is manufactured by a 3D printing precision injection molding method that combines paraffin 3D printing technology with lost-wax precision casting technology. The 3D printing precision injection molding method first prints the mold core for die casting production using paraffin 3D printing technology, and then uses lost-wax precision casting method to die cast the plastic mold.

[0021] Specifically, it may include:

[0022] Step 1: Unitized Mold Manufacturing Design

[0023] The mold core is designed using a modular processing design method. Based on the injection molding conditions, the mold core is regionally planned and designed as several integrated standardized processing units. The processing units are joined together by mortise and tenon joints using unified structural data.

[0024] Step 2: Pulp Experiment

[0025] By using resin 3D printing to rapidly prototyping mechanical parts, the accuracy of the mating positions is calculated.

[0026] A comprehensive fit analysis was conducted on the mold core structure printed with resin to identify and correct any points prone to problems.

[0027] The mold core for die casting production was 3D printed using red wax, and the final mold core test was conducted.

[0028] Step 3: Mold Processing

[0029] Place the red wax model, confirmed in the above steps, into the sandbox mold.

[0030] The sand box inside the tool was treated using a vibrator and a pressure plate.

[0031] Die casting

[0032] The resulting die-cast parts are heat-treated and then machined to the design dimensions.

[0033] Polish and electroplate the parts;

[0034] Step Four: Mold assembly.

[0035] Preferably, the mortise and tenon fitting structure type includes the following major category permutations and combinations:

[0036] 1) The convex and concave form combination by controlling the taper and precision of surface to surface;

[0037] 2) The工字形态结合 (It seems there is a wrong name in Chinese, please correct it. For now, I just keep it as it is);

[0038] 3) The trapezoidal dovetail form combination;

[0039] 4) The convex point planar combination;

[0040] 5) The pin-through combination.

[0041] Through the permutations and combinations of the above several structure types, the structural data summary precipitation of the mortise and tenon fitting can be realized, and it can be quickly practiced and processed in place through practice.

[0042] Furthermore, the present invention further improves the processing unit, which includes a functional end (71) and a heat dissipation end (72). The functional end (71) is the position for secondary processing according to the shape of the product, and the heat dissipation end (72) is the heat dissipation position constituted by the topological structure. And the topological structure can extend into the functional end according to the heat dissipation requirement to ensure the function realization.

[0043] The present invention also provides a casting plastic mold system combined with 3D printing technology. In this system, the plastic mold adopts the design method of modularizing the mold core, which is divided into several mold core units. Each mold core unit includes a functional end and a heat dissipation end. The functional end is the functional position of the mold core unit for secondary processing according to the shape of the product. The internal structure of the heat dissipation end is a support structure constituted by a network topological structure network filling structure, and the topological structure extends into the functional end; and this system also includes a slider unit (91), a glue injection unit (92), a lifter unit (93), an ejection unit (94) and a chute unit (95). Compared with the prior art that generally divides the mold core into a front mold, a rear mold and a slider and fastens the above structures with screws, the above structure of the present invention can disassemble the mold core into different units or quickly combine them without using screws.

[0044] Compared with the prior art, the mold made by the casting mold system and method combined with 3D printing technology for plastic products with uneven wall thickness according to the present invention has at least the following beneficial effects compared with the conventional mold:

[0045] 1) The weight will be reduced by 20%, making mold assembly smoother. In the future, when conditions permit, the weight will be reduced by more than 80% when the overall mold frame is integrally molded, which will facilitate workers to assemble quickly and meet the working weight of general robotic arms, laying the foundation for Industry 4.0 in the injection molding industry.

[0046] 2) Improves molding efficiency of thick rubber products by more than 100%.

[0047] 3) Accelerating the production cycle can save nearly half of the production cycle. The production cycle of a typical mold is 35 to 45 working days. With this method, human factors will be involved less in the processing, so it can be shortened to 15 working days.

[0048] 4) Increase mold life at a lower cost.

[0049] 5) Increased part replaceability allows for the accumulation of a large amount of data-driven experience.

[0050] The following description, in conjunction with the accompanying drawings, further illustrates the casting mold system of the present invention for plastic products with uneven wall thickness, which incorporates 3D printing technology. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the thick columnar topological core filling structure used in a specific embodiment of the present invention. Figure 1 ;

[0052] Figure 2 This is a schematic diagram of the square mesh topology core filling structure used in a specific embodiment of the present invention. Figure 2 ;

[0053] Figure 3 This is a schematic diagram of the core filling structure of a three-dimensional thick-column strong node topology used in a specific embodiment of the present invention. Figure 3 ;

[0054] Figure 4 This is a schematic diagram of the structure used in a specific embodiment of the present invention. Figure 4 ;

[0055] Figure 5 This is a schematic diagram of the structure used in a specific embodiment of the present invention. Figure 5 ;

[0056] Figure 6 This is a schematic diagram of the structure used in a specific embodiment of the present invention. Figure 6 ;

[0057] Figure 7a This is a schematic diagram of a mold core unit according to a specific embodiment of the present invention;

[0058] Figure 7bThis is a schematic diagram of a module unit with a network topology structure according to a specific embodiment of the present invention;

[0059] Figure 8 This is a schematic diagram of the existing mold structure;

[0060] Figure 9 This is a schematic diagram of the modular processing structure of the casting mold system combined with 3D printing technology for plastic products with uneven wall thickness according to the present invention.

[0061] Figure 10 - Figure 12 , Figure 13a and Figure 13b This is a schematic diagram illustrating the design concept of the mesh topology structure of the present invention;

[0062] Figure 14 This is a process flow diagram of a casting mold combining 3D printing technology for plastic products with uneven wall thickness, as described in this invention.

[0063] Figure 15 This is a schematic diagram of a combination of dovetail and straight groove according to the present invention. Detailed Implementation

[0064] The common solution to the defects of molds for plastic products with uneven wall thickness is to address them at the design level, that is, to abandon the original structure with uneven wall thickness and change it to a structure with uniform wall thickness to meet production requirements. However, this method has significant limitations. For example, in the field of mortise and tenon joints where the inventor works, due to the need for cultural heritage and respect for traditional structures, and because product manufacturing is primarily about recording history, this method is completely inapplicable to solving product problems.

[0065] Through several years of continuous production, the inventor discovered the core problem of this defect—the temperature of the injection-molded part cannot quickly drop to the molding temperature when it enters the core of the mold. Currently, the common solution to this problem is to add a "waterway" to the mold, a method that uses flowing water to lower the overall temperature of the mold. The traditional "waterway" method utilizes the specific heat capacity of steel to maintain a constant temperature for the entire mold system (the flowing water can be continuously maintained at around 37 degrees Celsius using electric heating; excessively cold water will continuously affect the mold's lifespan due to thermal expansion and contraction). This method involves laying water pipes in the center of a solid mold core. To ensure strength, the pipes are generally located in the center of the mold core. However, this heat dissipation method requires a long heat transfer time. The flowing water carries away the heat generated during injection molding, specifically the heat in the core of the mold core, which contradicts the goal of efficient injection molding production.

[0066] To address this issue, the inventors, through continuous research and development, have invented a new structure and design method that can solve the problem of rapid heat dissipation while ensuring the strength of the mold core. A detailed description of specific embodiments follows:

[0067] like Figure 1-6 The diagram shows an improved mold core structure of a casting mold system combined with 3D printing technology for plastic products with uneven wall thickness, according to the present invention. The method of the present invention to solve the processing defects caused by uneven wall thickness is mainly to set the mold core filling structure with a network topology inside the mold structure, so as to solve the problems of product surface shrinkage, incomplete filling, surface bulging, unstable product size, and inability to continue production for a long time due to uneven wall thickness.

[0068] The mold core of this invention is mainly composed of a force-bearing surface distributed on the surface of the mold core and an internal mold core filling structure. The mold core filling structure can adopt a variety of network topologies. The gaps formed in the middle of the network topology structure form interconnected spaces. Therefore, although the actual effects produced by using different topologies will be slightly different, the core principle is that the surface area can be increased by a hundred times through the network structure, thereby achieving a rapid heat dissipation effect (whether it is water contact or natural heat dissipation, the effect is 10 to 15 times the actual efficiency of the original mold).

[0069] This invention utilizes a network topology structure constructed through spatial combinations and transformations of hexahedrons such as cubes and cuboids for filling. Hexahedral transformations enable controllability of all structural nodes, allowing for rapid and arbitrary deformation of the shape to adapt to different object forms and achieve rapid and free changes in strength. Furthermore, additional sub-support structures can be constructed within the hexahedrons to handle special nodes and provide stronger structural design.

[0070] The following is in conjunction with the appendix Figure 9-1 3. The structure and design concept of the core filling structure with network topology adopted in this invention.

[0071] The core of this plastic mold is mainly composed of force-bearing surfaces distributed on the surface of the core and an internal structure with a network topology. The principle of the network topology structure of this invention is based on point design according to the cubic unit shape. For example: Figure 9 As shown, it is a cubic unit structure. The area within the frame formed by the twelve borders of this cube is the topological structure design region. The spatial design principle of the topological structure used in this invention is to ensure that the designed lines can fit point-to-point, such as... Figure 10The diagram shows a composite of two unit structures, with the endpoints of their corresponding mating surfaces coinciding. As illustrated, the network topology is composed of stacked cubic units, with connecting rods between the endpoints of each cubic unit forming a mesh support. The gaps between these connecting rods create interconnected spaces. Furthermore, the cubic mesh can embed trihedral or hexahedral structures, and different reinforcing support structures can be used to connect the nodes according to functional requirements, thus forming different functional components. For example, some connecting rods can be hollow structures with a flow-guiding function, allowing coolant to be injected into the fluid space formed by these hollow structures.

[0072] In addition, such as Figure 12 As shown, when calculating an object, the eight points of the quadrilateral on the surface of the object can be adjusted to conform to the shape of the object.

[0073] As those skilled in the art will know, all objects in our real lives can be simplified and decomposed into components composed of interconnected hexahedrons. By adjusting controllable points, the topological structure can be made to fit the components. Alternatively, existing model algorithms can be used to transform curved surfaces into key points for fitting, connecting four key points in a group to obtain the aforementioned pattern. (See also...) Figure 13a and Figure 13b As shown, after dividing the curved surface into quadrilaterals, topological structures can be used to design it. The cube of this invention originates from a regular representation of multiple points connected by lines in a topological structure. Applied to three-dimensional structures, it manifests as a deformation and replication of a regular structure. This invention will be introduced by analogy through enumeration, hoping to help understand the principle of its spatial composition. Any existing connection method can be used as a standalone spatial three-dimensional state according to the supporting concept of this invention. The core principle of its combination is the combination of countless spatial quadrilaterals.

[0074] like Figure 1-6 These are various network topologies obtained by the inventors through numerical simulation calculations. The internal structure diagrams of some specific embodiments are described below:

[0075] Example 1: Thick columnar topological structure core filling construction

[0076] See Figure 1Each connecting rod is designed to resemble a thick-walled pipe block, giving the structure of this specific embodiment strong pressure resistance. Considering the relatively complex mold structure of this invention, a new manufacturing method and process flow are researched, the details of which will be described later. To this end, to match this, a different material was chosen for mold 1 than the tool steel used in the prior art. In this specific embodiment, cast iron was selected. For parts of the same size, this topology can achieve up to approximately 88% of the strength of actual steel (because the thickness and density of the connecting nodes can be adjusted according to actual applications, the strength varies considerably; this invention uses the same material to first conduct 3D printing experiments to infer mechanical feasibility and proportion, and then applies it to steel to obtain experimental results with extremely high approximation). Its toughness and heat dissipation far surpass those of steel blocks.

[0077] Example 2: Core Filling Construction of Square Mesh Topology

[0078] like Figure 2 As shown, this structure uses the endpoints of a cube as nodes, with supporting links established between the diagonal endpoints, forming a square mesh structure. This topology has high toughness and can withstand high pressure. Practical applications have shown that its compressive life is higher than that of solid materials. This is because solid materials tend to peel off after repeated pressure, requiring re-welding. Taking S136 material as an example, repairing peeling off requires a significant amount of time. However, with this square mesh topology mold core filling structure, ensuring the thickness of the stress-bearing surface reaches 5mm can largely prevent similar issues. Furthermore, experimental tests show that this structure has better heat dissipation than the thick columnar topology of Example 1. Therefore, this structure should be preferred when the product's adhesive thickness reaches 16mm.

[0079] Example 3: Three-dimensional thick-walled column strong node topology

[0080] like Figure 3 As shown, a smaller cube is set inside the larger cube, and the nodes (endpoints) between the large and small cubes are connected by inclined columns. The advantage of this structure in this specific embodiment is that the radius of each structural point is 50% larger than that of the connection point, resulting in stronger compressive strength than the thick columnar structure in Embodiment 1. Furthermore, due to the larger space in the hollow part that allows airflow or liquid to pass through, its heat dissipation effect is better than the thick columnar strong node structure in Embodiment 1. However, the disadvantage is that its spatial interval is larger, and the stress surface of the product needs to be designed on the nodes to ensure that it will not deform or be damaged.

[0081] Please see below. Figure 4 - Figure 6As shown, it is a structural form of other types of topological structures designed by the inventor through digital modeling. It can be connected by links of various shapes to form a form in which several topological structures of different shapes overlap to meet the needs of different functions of support and flow guidance.

[0082] It should be noted that the above six topological structures are only illustrative examples and do not include all the structures of this invention. The advantages and disadvantages of different structures are only specifically listed here. In actual applications, there will be many other basic topological forms, all of which can be designed according to the above methods.

[0083] Additionally, please see Figure 7a and Figure 7b As shown, in a specific embodiment of the present invention, a design of modularizing the mold core is adopted, and each mold core unit 7 is composed of a functional end 71 and a heat dissipation end 72.

[0084] As shown in the figure, the functional end 71 is the functional position of the mold core unit 7, which needs to be processed secondaryly according to the shape of the product. The heat dissipation end 72 is the heat dissipation position formed by the above topology, and the topology can be extended into the functional end according to the heat dissipation requirements to ensure the functionality.

[0085] Based on the above-mentioned structural improvements, this invention further provides a method to solve the defects of complex structural processing and short lifespan of product molds.

[0086] Currently, the core of a traditional mold is usually machined from a single piece of thick steel. Then, through milling, planing, and grinding by fitters, the mold is made into a usable state. However, this processing method brings an unavoidable problem: the fitter's ability to reliably control the data. In practice, processing errors often occur due to the fitter's misunderstanding of the drawings.

[0087] In response to this situation, the existing solution is usually to use a standard spare parts library so that a backup plan can be used immediately if a problem occurs. However, this method is very strict on the standardized design of the mold, and since the parts to be processed have their own characteristics, it is difficult to standardize the design at this stage.

[0088] Therefore, this invention takes into account the advantages of 3D printing technology to quickly prepare the aforementioned parts, and this method has certain fundamental differences in process from conventional direct metal printing, as detailed below:

[0089] Since metal 3D printing cannot currently use mold steel, the existing patents disclosed on the application of metal 3D printing in plastic molds actually use commonly used materials for metal 3D printing to print existing mold structures, and their performance obviously cannot meet the requirements.

[0090] With the increasing maturity of 3D printing, parts with an accuracy of 2% millimeters can be obtained through paraffin 3D printing, which has advantages such as mature technology, low cost, and high efficiency. However, mainly because the carving and demolding of paraffin is quite cumbersome, it is difficult to generate sufficient economic benefits in general processing and production. Therefore, at present, lost-wax precision casting is generally used in jewelry processing, and paraffin printing casting is already widely used in the jewelry industry. Furthermore, this invention utilizes the material properties of paraffin 3D printing and therefore employs lost-wax precision casting technology. In view of this, this invention has developed a new process that applies the above casting technology to high-strength cast steel, and uses die casting to ensure that this processing method can be perfectly realized in the aforementioned method and structural form used to solve processing defects caused by inconsistent wall thickness.

[0091] In view of the aforementioned problems, and in accordance with the functional requirements of the corresponding topology design, lifespan details, etc., this invention discloses a process flow method that reduces the complexity of traditional methods, and significantly differs from existing mold processing processes. The specific details are as follows:

[0092] Traditional mold processing includes:

[0093] I. Mold Design

[0094] like Figure 8 As shown, it is a traditional one-piece mold design, with the front and back of the mold being a single unit.

[0095] 1. Determine the optimal solution based on mold size analysis.

[0096] 2. Flow channel design selection

[0097] 3. Product Classification and Layout

[0098] 4. Mold core design

[0099] 5. Determining the mold frame dimensions

[0100] 6. Feasibility analysis of machining programming

[0101] 7. Product molding simulation;

[0102] II. Mold Processing

[0103] 1. Custom mold base

[0104] 2. Rough machining of mold core and parts assembly

[0105] 3. Exquisitely carved bronze pieces

[0106] 4. The dimensions of the core part of the mold core are obtained through secondary machining using electrical discharge machining;

[0107] III. Mold Assembly

[0108] 1. A fitter uses finite element analysis to understand the various specifications of parts after rough machining.

[0109] 2. Analyze assembly dimensions using specifications.

[0110] 3. Perform fit analysis and planar analysis on assembly nodes.

[0111] 4. Machining the dimensions of the nodes to the required standard to form the assembly dimensions.

[0112] 5. Complete the assembly of ejector pins and flow channels.

[0113] 6. Continue until the mold can be successfully closed.

[0114] IV. Mold Core Details

[0115] 1. Fine processing such as polishing and sandblasting of the cavity area.

[0116] 2. Check that the closure is tight.

[0117] 3. Check the cavity for cracks;

[0118] V. Mold Experiment

[0119] 1. Injection Molding Production Experiment

[0120] 2. Check for any irregularities or jamming between parts.

[0121] 3. Adjust the injection molding parameters to obtain the complete product.

[0122] 4. After the mold temperature reaches the rated production conditions, continue testing for 24 hours and observe the mold for any issues by checking the condition of the parts.

[0123] 5. Check the availability of spare parts for easily damaged components.

[0124] 6. Final delivery and production.

[0125] During the research process, this invention also yielded a new processing flow through experimental innovation:

[0126] I. Design Phase

[0127] like Figure 8 The diagram shown is a schematic of a mold core with an integrated design in the prior art. In this invention, the mold core refers to the core position that fits with the product during injection molding and helps the product to be formed.

[0128] In the design of the part processing unit, the difference between the modular core unitized processing design of the present invention and the traditional design is that the original core was designed as an integral one. The unitized processing is to perform "block building" processing on the core part of the core after regional planning and calculation of injection molding conditions such as heat dissipation pressure. The difficulty of this processing technology lies in the scientific and reasonable mortise and tenon fit between each processing unit. This comes from the understanding of the traditional mortise and tenon structure, and actually accumulates some experience in space avoidance and analyzes the force modes of interference fit and clearance fit.

[0129] In the present invention, it can be seen that the core can be disassembled into different units without using screws. These units are integrally formed and combined with a universal mortise and tenon structure.

[0130] Please refer to Figure 9 , which is a schematic diagram of the unitized processing structure of the present invention. The mold system of the present invention includes: a slider unit 91, a gating unit 92, a lifter unit 93, an ejection unit 94, and a chute unit 95. Different from the prior art in which the core is divided into a front mold, a rear mold, and a slider and is fastened by screws, the present invention mainly realizes the functions of rapid assembly and disassembly by means of the slider and unit design. Further, please refer to Figure 15 a schematic diagram of a combination of a dovetail and a straight groove, in which the dovetail is responsible for ensuring that the slider does not displace up and down, and the straight groove is used to ensure sliding. Such sliders can all adopt this standard structural form. In the present invention, it is named a mortise and tenon structure applied to metal units due to the convex-concave fit and spatial rationality.

[0131] In the unitized processing of the present invention, each part is a standardized unit, and then the mortise and tenon fit is carried out through unified structural data.

[0132] The structural types of each unit can be divided into the following major categories:

[0133] 1) Convex-concave form combination

[0134] The simplest and most common combination method of convex-concave combination, which is combined by controlling the taper and accuracy of surface to surface;

[0135] 2)工字形态结合

[0136] A deformed combination of convex and concave, controlling the end face of the工字 to carry out precision control;

[0137] 3) Trapezoidal dovetail form combination

[0138] A method of restricting position, applied to structures with low requirements for accuracy;

[0139] 4) Convex point-plane combination

[0140] A high-precision fitting method, which can achieve a high degree of fit by grinding the convex points; It should be noted that there is an unclear expression "工字形态结合" in the original text. I translated it according to its literal meaning. If there is a more accurate name for this structure, it can be further corrected.

[0141] 5) Combination of thread and pin;

[0142] It uses a combination of convex and concave shapes to limit the position of structural components;

[0143] By arranging and combining the above structural types, the structural data of mortise and tenon joints can be summarized and accumulated, and through practice, it can be quickly practiced and processed in place.

[0144] 1. Unit Detail Design: The following are the core issues in unit design.

[0145] (1) Design the mold core forming position, allow for machining errors, and determine the machining process.

[0146] (2) Confirm the mechanical moving structure design to ensure that the topology described in Question 1 does not affect assembly;

[0147] I. Pulse Experiment

[0148] 4. For rapid prototyping of mechanical parts using resin 3D printing, the precision of the mating positions needs to be calculated (the tolerance range of resin 3D printing is generally ±0.05~0.15mm, and the machining precision is ±0.03~0.05). Therefore, precision calculations need to be performed on the details of the structural connections to confirm whether the assembly problem is caused by the mechanical structure design or by the tolerance. The mold core structure can be quickly verified through simple grinding.

[0149] 5. Conduct a comprehensive fit analysis on the mold core structure printed with resin, identify points prone to problems, and make corrections;

[0150] 6. Use red wax 3D printing to create the mold core for die casting production and conduct final mold core testing;

[0151] II. Mold Processing

[0152] 5. Place the confirmed red wax model into the sandbox tool, and connect a long stick that extends straight through the bottom of the tool and is exposed outside the sandbox to the bottom of the red wax model;

[0153] 6. Use a vibrator and pressure plate to treat the sand box inside the tool. This step is to ensure that the sand can fill the complex structure, thereby ensuring its functionality.

[0154] 7. Perform die casting;

[0155] 8. After obtaining the die-cast parts, they undergo conventional treatments such as annealing and then are machined to the design dimensions;

[0156] 9. Polishing and electroplating the parts ensures smooth assembly, and the electroplating layer can greatly enhance the hardness and life of the mold core (this is a routine operation).

[0157] III. Mold Assembly

[0158] By using 3D printing precision injection molding and modular design, the mold assembly stage will be very smooth, ensuring that the overall dimensions of the mold base processing position can be smoothly assembled, thus saving a lot of processing time;

[0159] IV. Mold Experiment

[0160] In the above embodiments, cast iron was used as the material for the final mold. Other materials suitable for casting processes, such as aluminum and titanium alloys, can also be used. This invention can be applied to high-strength aluminum modified products used in casting processes. Experiments have shown that it can achieve the hardness and tensile strength levels of general mold steel.

[0161] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A casting plastic mold, characterized in that, The core of the plastic mold is mainly composed of a stress surface distributed on the surface of the core and an internal structure of the core with a network topology structure. The network topology structure is formed by stacking several cube units. Each cube unit consists of a network support composed of several endpoints and connecting rods arranged between the endpoints. The spaces between the connecting rods of the network topology structure form interconnected spaces. The plastic mold is manufactured by a 3D printing precision injection molding method that combines a paraffin 3D printing process and a precision investment casting process. The 3D printing precision injection molding method is to first print the core for die-casting production through the paraffin 3D printing process, and then die-cast the plastic mold using the precision investment casting method.

2. The casting plastic mold according to claim 1, characterized in that, The stress surface is located at the nodes of the cubes in contact with it.

3. The casting plastic mold according to claim 1, characterized in that, The area within the square formed by the twelve side edges of the cube is the topological structure design area, and the contact surfaces of the cubes are in point-to-point contact, that is, the endpoints of the corresponding joint surfaces of any two units coincide.

4. The casting plastic mold according to claim 2, characterized in that, The 8 points of the quadrilateral of the stress surface are adjusted fluidly according to the shape of the core, so as to fit the shape of the core.

5. The casting plastic mold according to claim 3, characterized in that, The plastic mold is a mold die-cast using cast iron, aluminum or titanium alloy materials.

6. A manufacturing process incorporating 3D printing technology for manufacturing the casting plastic mold as described in claim 1, characterized in that, The plastic mold is manufactured by a 3D printing precision injection molding method that combines a paraffin 3D printing process and a precision investment casting process. The 3D printing precision injection molding method is to first print the core for die-casting production through the paraffin 3D printing process, and then die-cast the plastic mold using the precision investment casting method.

7. The manufacturing process combining 3D printing technology according to claim 6, characterized in that, It includes: Step 1: Mold unitized processing design The core is designed using the core unitized processing design method. The core is regionally planned according to the injection molding conditions and designed into several standardized processing units formed integrally. The processing units are tenoned and mortised through unified structural data; Step 2: Core experiment 1. Rapidly form mechanism parts through resin 3D printing to perform accuracy conversion on the mating positions; 2. Conduct a comprehensive mating analysis on the core structure printed by resin, and find the points prone to problems for correction; 3. Print the core for die-casting production through red wax 3D printing for the final core experiment; Step 3: Mold processing 1. Place the red wax model confirmed in the above steps into the sand box tool; 2. Use a vibrator and a pressing plate to process the sand box in the tool; 3. Conduct die-casting; 4. After heat-treating the obtained die-cast parts, perform machining to the designed dimensions; Step 4: Mold assembly.

8. The manufacturing process combining 3D printing technology according to claim 7, characterized in that, The structural types of the tenon and mortise joints include the following major category permutations and combinations: 1) Concave-convex form combination by controlling the taper and accuracy of surface-to-surface; 2)工字形态结合; 3) Trapezoidal dovetail form combination; 4) Convex point planar combination; [[ID= 9. The manufacturing process combining 3D printing technology according to claim 8, characterized in that, ​ 10. A system incorporating 3D printing technology for manufacturing a cast plastic mold as described in claim 1, characterized in that, The plastic mold is divided into several mold core units by a modular design of mold cores, and each mold core unit includes a functional end and a heat dissipation end. The functional end is a functional position of the mold core unit that is further processed according to the shape of the product. The internal structure of the heat dissipation end is a support structure composed of a network topology and a network filling structure, and the topology extends into the interior of the functional end. The system also includes a slider unit (91), a glue inlet unit (92), a shovel unit (93), an ejector unit (94), and a chute unit (95).

Images