A scaffold-polymer composite structure and a method of making the same

Abstract

The present application relates to a kind of preparation methods of skeleton-polymer composite structure, comprising: drawing the three-dimensional structure model of skeleton;Based on the three-dimensional structure model of skeleton, using adhesive jet additive manufacturing process to obtain skeleton;The skeleton obtained is placed into injection mold, and polymer is used as injection raw material and is injected into the cavity of the injection mold, cooling and demolding operation are carried out, and skeleton-polymer composite structure is obtained.The preparation method provided by the present application uses adhesive jet additive manufacturing process to obtain skeleton, compared with conventional 3D printing process such as laser 3D printing, can adapt to the preparation demand of skeleton with different shapes and complex structure, and can effectively improve production efficiency;Green body preparation, sintering and injection molding can be carried out simultaneously, which is conducive to realizing line operation.

Description

TECHNICAL FIELD

[0001] The present application relates to a skeleton-polymer composite structure and a preparation method thereof. BACKGROUND

[0002] With the development of the aviation, aerospace, ship and other high-tech industries, the requirements for lightweight load-bearing / energy-absorbing materials and structures are becoming higher and higher. In addition, in the field of consumer electronics and other fields, higher requirements for lightweight, waterproof sealing and other requirements are also put forward. The skeleton-polymer composite structure can meet the requirements of structural strength, lightweight, energy absorption and waterproof sealing at the same time. At present, such skeleton-polymer composite structures are mainly prepared by injection molding process, which has low preparation efficiency. There are also ways to prepare skeletons by laser 3D printing and then realize the combination of skeletons and polymers by injection molding process. However, this method has low production efficiency when preparing complex structures / shapes of skeletons, and the combination between the skeleton and the polymer needs to be improved, especially in the fields of aviation, aerospace, ship, weapon equipment and other fields. When the environment is harsh or after a long period of service, the polymer and the skeleton are easy to separate, which affects the working reliability and safety. SUMMARY

[0003] The present application relates to a skeleton-polymer composite structure and a preparation method thereof, which can at least solve some defects of the prior art.

[0004] The present application relates to a preparation method of a skeleton-polymer composite structure, comprising:

[0005] drawing a three-dimensional structure model of the skeleton;

[0006] based on the three-dimensional structure model of the skeleton, a skeleton is prepared by using an adhesive jet additive manufacturing process;

[0007] putting the prepared skeleton into an injection mold, injecting a polymer as an injection raw material into a cavity of the injection mold, cooling and demolding to obtain a skeleton-polymer composite structure.

[0008] As one of the embodiments, at least part of the ribs in the skeleton includes an inner core and an outer layer, the outer layer uses large particle powder raw material to form a surface layer pore in the outer layer, and the average particle size of the large particle powder raw material is in the range of 80-360 μm; when injection molding, the polymer fills the surface layer pore.

[0009] As one of the embodiments, the inner core uses small particle powder raw material, and the average particle size of the small particle powder raw material is in the range of 5-60 μm.

[0010] As one of the embodiments, the inner core raw material is at least one of metal powder, nylon powder and ceramic powder, and the outer layer raw material is metal powder or ceramic powder.

[0011] As one of the embodiments, at least part of the ribs in the framework comprises an inner core and an outer layer, and the outer layer adopts a mixture of A material and B material, wherein the B material is gasified at the sintering temperature of the inner core and the A material, so as to form surface layer pores in the outer layer; and the polymer fills the surface layer pores during injection molding.

[0012] As one of the embodiments, the inner core also adopts the A material, and the particle size of the A material of the inner core is not greater than the particle size of the A material of the outer layer.

[0013] As one of the embodiments, the A material is metal powder, and the B material is non-metal powder.

[0014] As one of the embodiments, the polymer is epoxy resin.

[0015] As one of the embodiments, the framework is a lattice framework.

[0016] The present application also provides a framework-polymer composite structure prepared based on the preparation method of the framework-polymer composite structure.

[0017] The present application has at least the following beneficial effects:

[0018] The preparation method provided by the present application adopts the binder jetting additive manufacturing process to prepare the framework, which can adapt to the preparation requirements of frameworks with different shapes and complex structures, and can effectively improve the production efficiency compared with conventional 3D printing processes such as laser 3D printing; the green body preparation, sintering molding and injection molding can be carried out at the same time, which is beneficial to realize the production line operation. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0020] Figure 1 The structural schematic diagram of the framework provided by the embodiments of the present application is shown in the figure;

[0021] Figure 2 The structural schematic diagram of the framework-polymer composite structure provided by the embodiments of the present application is shown in the figure;

[0022] Figure 3 The structural schematic diagram of the powder laying box provided by the embodiments of the present application is shown in the figure;

[0023] Figure 4 A schematic view of a combination of a plurality of powder spreading boxes. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0025] Embodiment one

[0026] The embodiment of the present application provides a preparation method of a skeleton-polymer composite structure, comprising:

[0027] drawing a three-dimensional structure model of the skeleton 11;

[0028] preparing the skeleton 11 by using an adhesive jet additive manufacturing process based on the three-dimensional structure model of the skeleton 11;

[0029] putting the prepared skeleton 11 into an injection mold, injecting a polymer 12 as an injection raw material into a cavity of the injection mold, cooling and demolding to obtain the skeleton-polymer composite structure.

[0030] The drawing of the three-dimensional structure model is generally realized by using related model drawing software, such as Solidworks or Rhino software.

[0031] The skeleton 11 can be designed in a corresponding shape according to actual product requirements, such as a columnar shape, a ring shape, a hollow body (such as a hollow spherical shape), etc. In one of the embodiments, the skeleton 11 is a lattice skeleton 11. Figure 1 And Figure 2 The node unit of the lattice skeleton 11 can be in a pyramid shape, a prism shape, a spherical shape, etc. The three-dimensional structure model of the skeleton 11 can be drawn according to the designed shape of the skeleton 11.

[0032] The preparation method provided in the embodiment can prepare the skeleton 11 by using the adhesive jet additive manufacturing process, which can adapt to the preparation requirements of skeletons 11 with different shapes and complex structures, and can effectively improve the production efficiency compared with conventional 3D printing processes such as laser 3D printing. The green body preparation, sintering forming and injection molding production can be carried out at the same time, which is beneficial to realize the production line operation.

[0033] In one of the embodiments, at least part of the ribs in the framework 11 comprises an inner core and an outer layer, the outer layer is formed by using large-particle powder raw materials to form surface layer porosity in the outer layer, the average particle size of the large-particle powder raw materials is in the range of 80-360 μm, and is further preferably controlled in the range of 120-200 μm; during injection molding, the polymer 12 fills the surface layer porosity. Based on the above scheme, the combination between the polymer 12 and the framework 11 can be effectively improved, the framework 11 can better support and constrain the polymer 12, and thus the structural strength and working reliability of the framework-polymer composite structure can be improved; the outer layer has relatively large porosity, which can reduce the self-weight of the framework 11 and the composite structure, and the porosity of the outer layer can be filled by the polymer 12, which can improve the structural performance of the outer layer to a certain extent, and can improve the corrosion resistance and other weather resistance of the framework 11; based on the characteristics of the binder jet additive manufacturing process, only the particle size of the outer layer powder raw materials needs to be selected to control the porosity and size of the outer layer, and thus the process is simple and easy to control, and the products have high consistency.

[0034] Further, the inner core is formed by using small-particle powder raw materials, and the average particle size of the small-particle powder raw materials is in the range of 5-60 μm. The inner core is formed by using small-particle powder raw materials, which can ensure the structural density and structural strength of the inner core after sintering, and thus ensure the structural strength and rigidity of the framework 11, and avoid the situation that the structural porosity of the outer layer of the rib leads to the decline of the structural performance of the framework 11; in particular, in the structure of the inner core-outer layer, the binder in the green body of the inner core is more easily removed during debinding due to the structural characteristics of the outer layer, which significantly improves the structural performance of the inner core and overcomes the problem that the binder is easily left in the traditional process.

[0035] The framework 11 is preferably a metal framework 11, and the inner core and the outer layer can be formed by using the same material or different materials. In one of the embodiments, the inner core raw material is at least one of metal powder, nylon powder and ceramic powder, and the outer layer raw material is metal powder or ceramic powder; wherein the metal powder can be titanium alloy powder, stainless steel powder, high-temperature alloy powder and refractory metal (such as molybdenum, tantalum, tungsten, etc.) powder.

[0036] In another embodiment, at least part of the struts in the skeleton 11 comprise an inner core and an outer layer, and the outer layer is formed by mixing the A material and the B material, wherein the B material is gasified at the sintering temperature of the inner core and the A material, so as to form surface layer pores in the outer layer; and the polymer 12 fills the surface layer pores during injection molding. Based on this scheme, the bonding between the polymer 12 and the skeleton 11 can be effectively improved, the skeleton 11 can better support and constrain the polymer 12, and thus the structural strength and working reliability of the skeleton-polymer composite structure can be improved; the outer layer has a relatively large porosity, which can reduce the self-weight of the skeleton 11 and the composite structure, and the pores in the outer layer can be filled with the polymer 12, which can improve the structural performance of the outer layer to a certain extent, and improve the corrosion resistance and other weather resistance of the skeleton 11.

[0037] Further, the inner core also uses the A material, and the particle size of the A material of the inner core is preferably not larger than that of the A material of the outer layer. For example, the particle size of the A material of the inner core is the same as that of the A material of the outer layer, which can reduce the types of powder raw materials, facilitate actual production, and reduce costs.

[0038] In one embodiment, the particle size of the B material is larger than that of the A material, so that the structural performance of the outer layer can be improved accordingly by selecting a smaller particle size of the A material while meeting the size requirement of the pores in the outer layer.

[0039] The skeleton 11 is preferably a metal skeleton 11, that is, the A material uses a metal material, such as titanium alloy powder, stainless steel powder, high-temperature alloy powder, and refractory metal (such as molybdenum, tantalum, tungsten, etc.) powder; and the B material can use a metal powder or a non-metal powder, as long as it can be gasified at the sintering temperature of the A material.

[0040] The volume ratio of the A material to the B material is considered based on the porosity of the outer layer, and in one embodiment, the volume ratio of the two is in the range of 3:10 to 7:10.

[0041] In one embodiment, the polymer 12 is an epoxy resin.

[0042] The embodiment of the present application also provides a skeleton-polymer composite structure prepared based on the preparation method of the skeleton-polymer composite structure.

[0043] Optionally, the composite structure can be used for active energy absorption and buffering protection during armor protection impact, lightweight structure weight reduction in aerospace, lightweight and weight reduction in consumer electronics, and waterproof sealing in various application scenarios.

[0044] Embodiment two

[0045] The embodiment provides a powder laying box 2, which is mainly used in additive manufacturing production.

[0046] The powder spreading box 2 comprises a box body 21 which can have the same appearance structure as the powder spreading box 2 in the field of additive manufacturing, be convenient to install into a printer, and be configured with a powder box driving mechanism, which will not be described here.

[0047] Compared with the way that the conventional powder spreading box 2 adopts a continuous material falling port 22, the powder spreading box 2 provided in the embodiment is provided with a plurality of material falling ports 22 at the bottom of the box body 21, the material falling ports 22 are arranged in a straight line and spaced apart in sequence, and each material falling port 22 is provided with a material unloading valve.

[0048] Based on the above design, the powder spreading flexibility and working reliability of the powder spreading box 2 can be improved, and the powder spreading operation of products with different shapes can be facilitated, for example, the powder spreading requirements of annular structures, segmented structures, hollow structures, etc. can be realized; specifically, a controller (such as a computer, etc.) can control all or part of the material falling ports 22 of the powder spreading box 2 to perform material falling operation according to the three-dimensional structure model of the target product.

[0049] Among them, the material falling port 22 can be a square material falling port 22, the length of the material falling port 22 is in the range of 1-10 mm, and the width is in the range of 1-10 mm; the material falling port 22 can also be a circular material falling port 22, and the diameter of the material falling port 22 is in the range of 1-10 mm.

[0050] Each material falling port 22 is preferably arranged at equal intervals. In one embodiment, the spacing between adjacent material falling ports 22 is in the range of 3-30 mm.

[0051] The number of material falling ports 22 is designed according to the specific working conditions, of course, it can be designed according to the demand for the maximum number of material falling ports 22, and in actual production, part of the material falling ports 22 can be selected to be opened; in the embodiment, the number of material falling ports 22 is in the range of 3-10.

[0052] Further preferably, as Figure 3 A plurality of partitions 23 are arranged in the box body 21, each partition 23 separates the lower part of the box body 21 into a plurality of material falling bins, and each material falling port 22 is arranged at the bottom of each material falling bin; based on this structure, each material falling port 22 can have a suitable material pressure to ensure the powder spreading effect.

[0053] Preferably, as Figure 3 The bottom of the box body 21 adopts a tapered structure that is wide at the top and narrow at the bottom, which can obtain a relatively large material pressure at the material falling port 22, and ensure the powder spreading effect and efficiency.

[0054] It can be understood that the powder spreading box 2 provided in the embodiment can be used in the above-mentioned embodiment one to complete the related powder spreading operation therein, for example, to perform powder spreading of the inner core or the outer layer, and the corresponding powder raw materials can be stored in the box body 21.

[0055] The above discharge valve can adopt a knife gate valve, a flap valve, etc. The valve driving mode is automatic driving, such as electric driving or pneumatic driving.

[0056] The embodiment also provides an additive manufacturing device, comprising a machine body, wherein a powder laying mechanism is arranged on the machine body, and the powder laying mechanism comprises a plurality of powder laying boxes 2.

[0057] Each powder laying box 2 is used for storing different powder raw materials. For example, when the first embodiment is applied, two powder laying boxes 2 can be configured, one of which is used for storing powder raw materials for the inner core, and the other is used for storing powder raw materials for the outer layer.

[0058] For example, Figure 4 Each powder laying box 2 is arranged in a straight line, and the arrangement direction is perpendicular to the arrangement direction of the discharge port 22 of a single powder laying box 2.

[0059] Preferably, each powder laying box 2 is respectively configured with a powder box driving mechanism, that is, each powder laying box 2 is independently driven, which can ensure the powder laying operation requirements of different raw materials, and the working flexibility and reliability are relatively high.

[0060] In one embodiment, the additive manufacturing device is an adhesive jet additive manufacturing device, and correspondingly, an adhesive jet module is also arranged on the machine body, which is a conventional structure in the field and is omitted here.

[0061] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a skeleton-polymer composite structure, characterized in that: include: Draw a three-dimensional structural model of the skeleton; Based on the three-dimensional structural model of the skeleton, the skeleton was prepared using the adhesive jetting additive manufacturing process; placing the prepared skeleton into an injection mold, injecting a polymer as an injection raw material into the cavity of the injection mold, cooling and performing a demoulding operation to obtain a skeleton-polymer composite structure; In the skeleton, at least part of the bone ridge includes an inner core and an outer layer, the outer layer is made of large-particle powder raw material to form surface pores in the outer layer, and the average particle size of the large-particle powder raw material is in the range of 80 to 360 μm; the inner core is made of small-particle powder raw material, and the average particle size of the small-particle powder raw material is in the range of 5 to 60 μm; Alternatively, the outer layer is made of a mixture of material A and material B, wherein material B is gasified at the sintering temperature of the inner core and material A, thereby forming surface pores in the outer layer; During injection molding, the polymer fills the surface pores.

2. The method for preparing a skeleton-polymer composite structure according to claim 1, wherein: When the outer layer is made of large-particle powder raw material and the inner core is made of small-particle powder raw material, the inner core raw material is at least one of metal powder, nylon powder and ceramic powder, and the outer layer raw material is metal powder or ceramic powder.

3. The method for preparing a skeleton-polymer composite structure according to claim 1, wherein: When the outer layer is made of a mixture of material A and material B, the inner core is also made of material A, and the particle size of material A in the inner core is not larger than that of material A in the outer layer.

4. The method for preparing a skeleton-polymer composite structure according to claim 1, wherein: When the outer layer is made of a mixture of material A and material B, the material A is metal powder; and the material B is non-metal powder.

5. The method for preparing a skeleton-polymer composite structure according to claim 1, wherein: The polymer is epoxy resin.

6. The method for preparing a skeleton-polymer composite structure according to any one of claims 1 to 5, characterized in that: The skeleton is a lattice skeleton.

7. A skeleton-polymer composite structure, characterized in that: The skeleton-polymer composite structure is prepared based on the preparation method of any one of claims 1 to 6.

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