A 3D printing polymer alloy strength control method

Abstract

The present invention discloses a 3D printing polymer alloy strength control method, which relates to the technical field of polymer material processing and molding. The present invention includes step 1, obtaining the viscosity-shear rate curve of the polymer alloy material at different temperatures, and determining the nozzle temperature and printing speed of the 3D printer printing molding according to the characteristic shear rate of the 3D printer nozzle and the viscosity requirement window of the material; step 2, if there is crystalline material in the polymer alloy material, using differential scanning calorimetry to test the crystallization temperature of the polymer alloy material, and the heating temperature of the printing platform of the 3D printer is lower than the crystallization temperature of the polymer alloy material; if there is no crystalline material in the polymer alloy material, the heating temperature of the printing platform of the 3D printer is lower than the nozzle temperature; step 3, preparing the polymer alloy into a filament for 3D printing. The present invention accurately and efficiently controls the alloy strength of polymer printed parts without changing the polymer material ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material processing and molding, and in particular to a method for controlling the strength of a 3D printed polymer alloy. Background Art

[0002] A polymer alloy is a polymer composite material made by uniformly mixing two or more polymer materials in a specific proportion. Different polymer materials have different physical and chemical properties, such as crystal morphology, mechanical strength, and heat resistance. The application of a single polymer material is often limited by its relatively fixed and difficult-to-control properties, especially mechanical strength. By creating a polymer alloy from two or more polymer materials with different properties, the advantages of each material can be fully utilized. Furthermore, the alloy's performance can be more easily controlled, allowing for more economical and efficient production of polymer parts that meet diverse application requirements.

[0003] Currently, the mechanical strength of polymer alloys is typically controlled through traditional processing methods such as extrusion and injection molding, and is primarily achieved by changing the alloy material ratio. This change in ratio not only affects the alloy's strength, but also other properties such as hardness, thermal performance, and weather resistance, making it difficult to precisely control the strength of polymer alloys. Heat treatment of polymer alloy parts is a control method that does not change the material ratio, but it has a less significant effect on strength control.

[0004] Therefore, to address the shortcomings of the existing technology, we propose a 3D printing polymer alloy strength control method. Summary of the Invention

[0005] The purpose of the present invention is to propose a 3D printing polymer alloy strength control method to achieve accurate and efficient control of the polymer alloy strength without changing the material ratio during the 3D printing process.

[0006] The technical solution adopted in the present invention is as follows:

[0007] The present invention is a 3D printing polymer alloy strength control method, comprising the following steps:

[0008] Step 1: Use a rheometer to test the polymer alloy material to obtain the viscosity-shear rate curve of the polymer alloy material at different temperatures. According to the characteristic shear rate of the 3D printer nozzle and the viscosity requirement window of the material, the nozzle temperature and printing speed of the 3D printer are determined;

[0009] Step 2: If there is crystalline material in the polymer alloy material, the crystallization temperature of the polymer alloy material is tested using differential scanning calorimetry, and the printing platform heating temperature of the 3D printer is selected to be lower than the crystallization temperature of the polymer alloy material; if there is no crystalline material in the polymer alloy material, the printing platform heating temperature of the 3D printer is selected to be lower than the nozzle temperature;

[0010] Step 3: Prepare the polymer alloy into filaments for 3D printing. Before printing, preheat the printing platform using the printing platform temperature obtained in step 2, and start 3D printing after the printing platform temperature stabilizes.

[0011] Furthermore, in step 1, a corresponding extrusion speed is selected as the printing speed of the 3D printer according to the shear rate for maintaining low viscosity, and the printing speed is greater than 3000 mm / min.

[0012] Furthermore, in step 2, when there is crystalline material in the polymer alloy material, a temperature 20°C-50°C lower than the crystallization temperature of the polymer alloy material is selected as the heating temperature of the printing platform; when there is no crystalline material in the polymer alloy, a temperature 80°C-120°C lower than the nozzle temperature is selected as the heating temperature of the printing platform, and the lowest heating temperature of the printing platform is room temperature.

[0013] Furthermore, in step 3, the polymer alloy is prepared into a filament with a diameter of 1.75±0.05 mm and 3D printed using a 3D printer.

[0014] Furthermore, the 3D printing process method adopted by the 3D printer is specifically a fused deposition modeling process, and the 3D printing process parameters are specifically as follows: using the nozzle temperature and printing speed obtained in step 1, using the printing platform temperature obtained in step 2 to preheat the printing platform, the nozzle diameter d is 0.2~0.8mm, the 3D printing layer thickness is 0.4d~0.8d, and the 3D printing filling rate is 100%.

[0015] Furthermore, the maximum heating temperature of the printing platform of the 3D printer is ≥120°C, the maximum heating temperature of its nozzle is ≥260°C, and its fastest printing speed is ≥9000mm / min.

[0016] Furthermore, the printing platform material of the 3D printer is a lattice glass plate or a glass fiber reinforced epoxy resin plate, and the printing platform is coated with PVA glue, PVP glue or epoxy board glue.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] The present invention discloses a method for controlling the strength of 3D-printed polymer alloys. The method uses a polymer alloy to perform rheological and thermal property tests on the material before 3D printing. Appropriate 3D printing parameters are selected based on the physical and chemical properties of the alloy with a specific ratio. The shear field and thermal field effects in the 3D printing process are utilized to generate a special microstructure with a self-reinforcement effect in the polymer alloy printed part. The strength of the polymer alloy can be significantly improved through a molding method without changing the alloy material ratio. Effective strength control can be achieved through the selection of process parameters, and the method has universal applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort, among which:

[0020] Figure 1 It is the viscosity-shear rate curve of polymer alloy material;

[0021] Figure 2 This is a test curve of the crystallization temperature of polymer alloy materials;

[0022] Figure 3 This is a comparison chart of the strength of 3D printed polymer alloys. DETAILED DESCRIPTION

[0023] In order to make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only intended to explain the present invention and are not intended to limit the present invention. That is, the embodiments described herein are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and illustrated in the drawings herein may be arranged and designed in various different configurations.

[0024] It should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, product or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, product or apparatus.

[0025] Example 1

[0026] The present invention is a method for controlling the strength of a 3D printed polymer alloy, and the specific steps are as follows:

[0027] Step 1: Use a rheometer to test a polypropylene / polyethylene (weight ratio 80:20) polymer alloy material to obtain the viscosity-shear rate curve of the polymer alloy material at different temperatures, such as Figure 1 As shown, the appropriate temperature is selected based on the characteristic shear rate of the selected 3D printer nozzle and the required viscosity window for the material. In this embodiment, 210°C is selected as the nozzle temperature for 3D printing. The corresponding nozzle extrusion speed is selected as the 3D printing speed based on the shear rate that can maintain relatively low viscosity. In this embodiment, the printing speed is selected as 3000 mm / min.

[0028] Step 2: Use differential scanning calorimetry to test the crystallization temperature of the polymer alloy material. Figure 2 The figure shows a crystallization temperature test curve. A temperature 20°C-50°C lower than the crystallization end temperature is selected as the printing platform heating temperature of the 3D printer. In this embodiment, the printing platform heating temperature is selected to be 90°C.

[0029] In step 3, the polymer alloy is prepared into a filament with a diameter of 1.75±0.05mm using a fused deposition modeling process for 3D printing. Before printing, the printing platform is preheated using the printing platform heating temperature obtained in step 2. Printing begins after the platform temperature stabilizes. The 3D printing process parameters are as follows: the nozzle temperature and printing speed obtained in step 1; the nozzle diameter d ranges from 0.2 to 0.8mm, with d selected as 0.4mm in this example; the layer thickness is preferably 0.4d to 0.8d, with 0.2mm selected in this example; the fill factor is 100%; and other parameters are selected as appropriate. The 3D printer used in this invention preferably uses a lattice glass plate or a glass fiber-reinforced epoxy resin plate as the printing platform material, coated with PVA glue, PVP glue, or epoxy plate adhesive to enhance the bonding between the platform and the polymer alloy. In this example, a lattice glass plate coated with PVA glue is used.

[0030] The performance of polymer alloys 3D printed by the method of the present invention was compared and analyzed. Figure 3 The figure shows the strength comparison of polymer alloy materials. CPP and CPE are polymer parts formed by traditional compression molding method, while the other five PP / PE are polymer parts printed at different printing speeds. Figure 3 The analysis results show that the alloy 3D-printed using the method of the present invention has high strength, and when the printing speed is 3000 mm / min, the 3D-printed alloy strength is the highest, achieving effective control of the strength of the 3D-printed polymer alloy.

[0031] Example 2

[0032] The present invention is a method for controlling the strength of a 3D printed polymer alloy, and the specific steps are as follows:

[0033] Step 1: Use a rheometer to test a polypropylene / polystyrene (80:20 weight ratio) polymer alloy to obtain viscosity-shear rate curves at different temperatures. Select an appropriate temperature based on the characteristic shear rate of the selected 3D printer nozzle and the required viscosity window for the material. In this example, 230°C was selected as the nozzle temperature for 3D printing. Based on the shear rate that maintains a relatively low viscosity, an extrusion speed was selected as the 3D printing speed. In this example, a printing speed of 9000 mm / min was selected.

[0034] Step 2: Use differential scanning calorimetry to test the crystallization temperature of the polymer alloy material, and select a temperature 20°C-50°C lower than the crystallization end temperature as the printing platform heating temperature of the 3D printer. In this embodiment, the printing platform temperature is selected to be 90°C.

[0035] In step 3, the polymer alloy is prepared into a filament with a diameter of 1.75±0.05mm using a fused deposition modeling process for 3D printing. Before printing, the printing platform is preheated using the printing platform heating temperature obtained in step 2. Printing begins after the platform temperature stabilizes. The 3D printing process parameters are as follows: The key parameters are the nozzle temperature and printing speed obtained in step 1; the nozzle diameter d is preferably 0.2-0.8mm, with 0.2mm selected in this embodiment; the layer thickness is preferably 0.4-0.8d, with 0.1mm selected in this embodiment; the fill factor is 100%; and other parameters are selected as appropriate. The 3D printer used in this invention preferably uses a lattice glass plate or a glass fiber-reinforced epoxy resin plate as the printing platform material, coated with PVA glue, PVP glue, or epoxy plate adhesive to enhance the bonding between the platform and the polymer alloy. In this embodiment, a lattice glass plate coated with PVA glue is selected.

[0036] A comparative analysis of the properties of polymer alloys 3D-printed using the method of the present invention was conducted. The results showed that the process parameters selected using the method of the present invention make the alloy strength of the 3D-printed polymer much higher than the strength of the alloy printed and pressed using ordinary parameters, thereby achieving effective control of the strength of the 3D-printed polymer alloy.

[0037] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be conceived by a person skilled in the art within the technical scope disclosed by the present invention without inventive effort should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined in the claims.

Claims

1. A 3D printing polymer alloy strength control method, characterized in that: The following steps are involved: Step 1: Use a rheometer to test the polymer alloy material to obtain the viscosity-shear rate curve of the polymer alloy material at different temperatures. According to the characteristic shear rate of the 3D printer nozzle and the viscosity requirement window of the material, the nozzle temperature and printing speed of the 3D printer are determined; Step 2: If there is crystalline material in the polymer alloy material, the crystallization temperature of the polymer alloy material is tested using differential scanning calorimetry, and the printing platform heating temperature of the 3D printer is selected to be lower than the crystallization temperature of the polymer alloy material; if there is no crystalline material in the polymer alloy material, the printing platform heating temperature of the 3D printer is selected to be lower than the nozzle temperature; Step 3: Prepare the polymer alloy into filaments for 3D printing. Before printing, preheat the printing platform using the printing platform temperature obtained in step 2, and start 3D printing after the printing platform temperature stabilizes.

2. A 3D printing polymer alloy strength control method according to claim 1, characterized in that: In step 1, a corresponding nozzle extrusion speed is selected as the printing speed of the 3D printer according to the shear rate that maintains low viscosity, and the printing speed is greater than 3000 mm / min.

3. The 3D printing polymer alloy strength control method according to claim 1, characterized in that: In step 2, when there is crystalline material in the polymer alloy material, the printing platform heating temperature is selected to be 20°C-50°C lower than the crystallization temperature of the polymer alloy material; when there is no crystalline material in the polymer alloy, the printing platform heating temperature is selected to be 80°C-120°C lower than the nozzle temperature, and the lowest printing platform heating temperature is room temperature.

4. The 3D printing polymer alloy strength control method according to claim 1, characterized in that: In step 3, the polymer alloy is prepared into a filament with a diameter of 1.75±0.05 mm and 3D printed using a 3D printer.

5. A 3D printing polymer alloy strength control method according to any one of claims 1 to 4, characterized in that: The 3D printing process method adopted by the 3D printer is specifically a fused deposition modeling process, and the 3D printing process parameters are specifically as follows: using the nozzle temperature and printing speed obtained in step 1, preheating the printing platform using the printing platform temperature obtained in step 2, the nozzle diameter d is 0.2-0.8 mm, the 3D printing layer thickness is 0.4d-0.8d, and the 3D printing fill rate is 100%.

6. A 3D printing polymer alloy strength control method according to claim 5, characterized in that: The maximum heating temperature of the printing platform of the 3D printer is ≥120°C, the maximum heating temperature of its nozzle is ≥260°C, and its fastest printing speed is ≥9000mm / min.

7. The 3D printing polymer alloy strength control method according to claim 1, characterized in that: The printing platform material of the 3D printer is a lattice glass plate or a glass fiber reinforced epoxy resin plate, and the printing platform is coated with PVA glue, PVP glue or epoxy board glue.

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