3D printing method for thin-walled Permalloy parts

Abstract

The present application discloses a 3D printing method for thin-walled Permalloy parts, including: three-dimensional modeling of thin-walled parts and model data processing; importing the processed model into a 3D printing device for slicing and printing path planning, setting the placement and processing direction of the parts, and generating a printing program; setting the printing parameters so that the model has no filling parameters when slicing and only retains the standard contour scanning parameters, and printing based on the printing program; after printing, the parts are cleaned out of the printing device and cut off from the substrate to obtain the printed thin-walled parts. If the filling parameters are turned on, the energy of heat dissipation during sintering of the internal entity will also cause the surrounding powder to semi-melt, and the wall thickness will exceed the required size. The present application sets the printing parameters so that the model has no filling parameters when slicing and only retains the standard contour scanning parameters. It only needs to let the laser spot scan along the model contour for one circle, and the wall thickness of the part can be close to the required size, thereby improving the printing efficiency and molding quality of Permalloy thin-walled parts.

Description

Technical Field

[0001] The present application relates to the field of additive manufacturing technology, and more specifically, to a 3D printing method for Permalloy thin-walled parts. Background Art

[0002] Thin-walled parts have the advantages of high strength, light weight, material saving and compact structure. As important parts, they are widely used in industries such as machinery, automobiles and aviation, but thin-walled parts also have relatively low stiffness. Permalloy (i.e., iron-nickel alloy, the nickel content range is very wide, between 35% and 90%. The biggest feature of Permalloy is that it has a very high weak magnetic field permeability, and their saturation magnetic induction intensity is generally between 0.6 and 1.0 T.) is a soft magnetic alloy with high magnetic permeability and low coercivity. It is widely used in electronics, communications, aerospace and military fields due to its excellent magnetic properties, processing properties and heat treatment properties. Permalloy is suitable for magnetic shielding, low-loss micromotors, magnetic sensors and magnetic sensitive elements. As a thin-walled honeycomb structure, it has the characteristics of high strength, high rigidity, good stability, strong conductivity and good electromagnetic shielding effect. The honeycomb structure made of Permalloy material, the electromagnetic waves entering the honeycomb plate are reflected and absorbed inside the honeycomb plate, which can effectively reduce electromagnetic interference.

[0003] In traditional processing technology, the smaller the volume of the parts and the thinner the thickness of the parts, the more likely they are to shrink, warp and other deformations during the manufacturing process, and the more difficult the processing is. 3D printing is a high-end digital manufacturing technology that has developed rapidly in recent years. It is a rapid prototyping method that uses materials to accumulate layer by layer to manufacture solid parts. As the most cutting-edge and most promising technology in the entire 3D printing system, metal 3D printing is an important development direction for the intelligent manufacturing industry. SLM (selective laser melting) metal 3D printing technology uses high-energy-density lasers as heat sources to melt the laid metal powder layer by layer, and obtain a metal component after cooling and solidification. The component can achieve very high surface dimensional accuracy and surface quality, solving the technical problems of difficult processing, long processing cycle and high cost of complex metal parts, and realizing the manufacturing of complex metal parts that are difficult or impossible to process by traditional manufacturing methods.

[0004] Compared with traditional manufacturing processes, laser selective melting technology has the characteristics of mold-free integrated forming, high dimensional accuracy and good surface quality, which is very suitable for the manufacture of thin-walled Permalloy parts, and its advantages are significant. However, the residual stress of thin-walled Permalloy parts is large during the printing process, which is prone to warping, and the parts are prone to cracking during the subsequent processing. The thin wall has poor rigidity and is prone to deformation, which makes it difficult to form thin-walled Permalloy parts using 3D printing. Summary of the invention

[0005] In response to at least one defect or improvement need in the prior art, the present application provides a 3D printing method for Permalloy thin-walled parts, which is used to improve the printing efficiency and molding quality of Permalloy thin-walled parts and solve the residual stress and cracking problems of the parts.

[0006] To achieve the above objectives, the present application provides a 3D printing method for a Permalloy thin-walled part, comprising:

[0007] Perform three-dimensional modeling of thin-walled parts, perform data processing on the constructed three-dimensional model, and obtain the processed three-dimensional model;

[0008] Import the processed 3D model into the slicing software of the 3D printing device for slicing and printing path planning, set the placement and processing direction of thin-walled parts, and generate the printing program;

[0009] Setting printing parameters so that the three-dimensional model has no filling parameters and only retains standard contour scanning parameters when slicing, and 3D printing the thin-walled part based on the printing program;

[0010] After printing is completed, the thin-walled parts are cleaned out of the 3D printing equipment and cut off from the substrate to obtain the printed Permalloy thin-walled parts.

[0011] Furthermore, the printing parameter setting method of making the three-dimensional model have no filling parameters and only retain the standard contour scanning parameters during slicing includes:

[0012] The first contour offset value in the contour offset parameter is set to 0.07-0.09 mm and changed in association;

[0013] The value range of the second contour offset value is: 0.11-0.13mm;

[0014] The value range of the third contour offset value is: 0.14-0.16mm;

[0015] The fourth contour offset value range is: 0.17-0.19mm;

[0016] The second to fourth contour offset values ​​are obtained by associated changes in the first contour offset value.

[0017] Further, the first profile offset value is set to 0.09 mm;

[0018] The second to fourth profile offset values ​​are respectively as follows: 0.13 mm, 0.16 mm and 0.19 mm.

[0019] Furthermore, setting the placement and processing direction of thin-walled parts includes:

[0020] The placement direction relative to the printing chamber of the 3D printing device is to place the parts in sequence from the position close to the powder supply cylinder, and the thin-walled parts are placed vertically relative to the base plate;

[0021] The processing direction is to print and shape in sequence from the air suction port to the air blowing port.

[0022] Furthermore, the parameters that need to be set when printing include:

[0023] The profile scanning power is set to 180-250W; the profile scanning speed is set to 800-1000mm / s;

[0024] The spot size is set to 70-90μm; the powder spreading scraper is leveled to a distance of no more than 0.05mm from the substrate; the substrate preheating temperature is set to 80-120℃; the wind pressure is set to 270-320Pa; a layer thickness of 0.03-0.04mm is used for printing; and the number of contour scans is set to 1.

[0025] Further, the profile scanning power was set to 180W; the profile scanning speed was set to 800mm / s;

[0026] The spot size was set to 90 μm; the substrate preheating temperature was set to 100°C; the wind pressure was set to 300 Pa; and the layer thickness was 0.04 mm for printing.

[0027] Furthermore, before 3D printing the thin-walled parts, the following steps are also included:

[0028] High-purity argon gas with a purity of at least 99.99% is introduced into the processing chamber of the 3D printing equipment as a protective gas, and 3D printing can only be performed when the oxygen content in the processing chamber is less than 0.1%.

[0029] Furthermore, the wall thickness of the printed Permalloy thin-walled parts ranges from 0.2 to 0.4 mm.

[0030] Furthermore, the metal powder material used for printing thin-walled parts is 15-53 μm Permalloy Fe-Ni50.

[0031] Furthermore, the printed Permalloy thin-walled parts have a hexagonal honeycomb shape as a whole.

[0032] In general, the above technical solutions conceived by the present application can achieve the following beneficial effects compared with the prior art:

[0033] (1) If the filling parameter is turned on, the heat dissipation energy during sintering of the internal entity will also cause the surrounding powder to semi-melt, and the wall thickness will exceed the required size. This application sets the printing parameters so that the model has no filling parameters during slicing and only retains the standard contour scanning parameters. By simply allowing the laser spot to scan along the model contour once, the part wall thickness can be close to the required size, thereby improving the printing efficiency and molding quality of Permalloy thin-walled parts.

[0034] (2) This application sets the first profile offset value in the profile offset parameter to 0.07-0.09 mm and changes it in association; the second to fourth profile offset values ​​are obtained by changing the first profile offset value in association. The residual stress and cracking problems of the parts are solved from the perspective of molding process parameters, and a thin-walled part whose mechanical properties and wall thickness meet the use requirements is obtained, so that the wall thickness dimensional accuracy of the standard thin-walled part can reach ±0.05 mm, the tensile strength ≥500 MPa, and the elongation ≥35%.

[0035] (3) The larger the molding area of ​​each layer, the greater the internal stress, which leads to a greater possibility of deformation and warping. In the present application, the thin-walled parts are placed vertically relative to the substrate, and the single-layer molding area is smaller. They can be sintered directly with the molding substrate, without the need to add a separate thin-walled structure for support, thereby reducing production costs. The installed molding substrate serves as the bottom support for the molded part (printed thin-walled part), which can prevent the molded part from shifting or warping during the construction process, reducing residual stress to a certain extent and avoiding cracking problems as much as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A core flow chart of a 3D printing method for a Permalloy thin-walled part provided in an embodiment of the present application;

[0038] Figure 2 A schematic diagram of the planar structure of a thin-walled part provided in an embodiment of the present application;

[0039] Figure 3 A schematic diagram of the placement of thin-walled parts provided in an embodiment of the present application;

[0040] Figure 4 A schematic diagram of the three-dimensional structure of a thin-walled part provided in an embodiment of the present application;

[0041] Figure 5A diagram illustrating contour offset and fill offset provided in an embodiment of the present application. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0043] The terms "first", "second" or "third" etc. in the specification, claims or the above-mentioned drawings of this application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" or "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units inherent to these processes, methods, products or devices.

[0044] The residual stress of thin-walled Permalloy parts is large during the printing process, which is prone to warping and cracking during the subsequent processing. The thin wall has poor rigidity and is prone to deformation, which makes it difficult to form thin-walled Permalloy parts using 3D printing. Figure 1 An embodiment of the present application proposes a 3D printing method for a Permalloy thin-walled part, and the 3D printing method may mainly include the following steps.

[0045] Step 1: Perform three-dimensional modeling of thin-walled parts, perform data processing on the constructed three-dimensional model, and obtain a processed three-dimensional model.

[0046] The wall thickness of the thin-walled parts ranges from 0.2 to 0.4 mm. Some traditional similar technical solutions generally require a separate thin-wall structure to support the thin-walled parts when three-dimensional modeling of parts, while the permalloy thin-walled parts in this embodiment do not need to be supported by a separate thin-wall structure when three-dimensional modeling, thereby reducing production costs.

[0047] Data processing mainly includes converting the constructed three-dimensional model into STL, SLC and other file formats that can be recognized by 3D printing equipment.

[0048] Step 2: Import the processed 3D model into the slicing software of the 3D printing device for slicing and printing path planning, set the placement and processing direction of thin-walled parts, and generate a printing program.

[0049] When confirming the placement of parts, the placement direction relative to the printing chamber of the 3D printing equipment is from the position close to the powder supply cylinder, and the placement direction of the thin-walled parts themselves is vertical (vertically placed relative to the substrate surface). Figure 2-Figure 4 .

[0050] The processing direction is to print and shape in sequence from the air suction port to the air blowing port.

[0051] The distance between the thin-walled parts and the edge of the substrate and the spacing between two adjacent rows of parts along different directions are set to be no less than 3 mm.

[0052] The larger the molding area of ​​each layer, the greater the internal stress, which leads to a greater possibility of deformation and warping. In this embodiment, the thin-walled parts are placed vertically relative to the substrate, and the single-layer molding area is smaller. They can be sintered directly with the molding substrate, and there is no need to add a thin-walled structure separately for support, thereby reducing production costs. The installed molding substrate serves as the bottom support of the molded part, which can prevent the molded part from shifting or warping during the construction process, and to a certain extent also reduces residual stress and avoids cracking problems as much as possible.

[0053] Step 3: Setting printing parameters so that the three-dimensional model has no filling parameters during slicing and only retains standard contour scanning parameters, and performing 3D printing on the thin-walled parts based on the printing program.

[0054] The smaller the layer thickness, the better the surface quality of the thin-walled parts, but the overall printing time will increase. In this embodiment, a layer thickness of 0.03-0.04 mm is selected for printing, and both the printing quality and the required printing time can be better guaranteed. Preferably, a layer thickness of 0.04 mm is selected for printing, which can best balance the printing quality and the required printing time.

[0055] Thin-walled parts are divided into entities and contours during molding. In order to ensure the quality of the interior and surface of thin-walled parts, there is a certain gap between the contour and the edge of the part entity during contour scanning. The size of this position is adjusted by the contour offset setting. In this embodiment, the X / Y contour offset parameters are adjusted to 0.07-0.09mm and changed in association, where the parameter range of contour offset 1 is: 0.07-0.09mm; the parameter range of contour offset 2 is: 0.11-0.13mm; the parameter range of contour offset 3 is: 0.14-0.16mm; the parameter range of contour offset 4 is: 0.17-0.19mm; such parameter settings make the three-dimensional model have no filling parameters during slicing (where the parameter range of the filling offset value is 0.10-0.12mm), only the standard contour scanning parameters are retained, and the number of contour scans is set to 1. Preferably, contour offset 1 is 0.09mm, contour offset 2 is 0.13mm, contour offset 3 is 0.16mm, and contour offset 4 is 0.19mm.

[0056] The data of the last three offsets (Contour Offset 2-Contour Offset 4) are obtained by changing the associated contour offset 1. Because when the laser is formed at different positions, there will be deviations when the spot scans the four sides of the part (the center of the spot is scanned along the edge of the 3D model part, and the radius of the spot exceeds the edge size of the model part, resulting in a larger size of the final formed part), and the four sides need to have different offset values ​​to compensate.

[0057] refer to Figure 5 , X / Y profile offset (abbreviated as profile offset) is the offset of the profile scan line relative to the nominal profile of the part. Profile offset 1, profile offset 2, profile offset 3 and profile offset 4 respectively represent the offset of the first profile (the first profile corresponds to the first edge, and the same applies to other profiles), the offset of the second profile, the offset of the third profile and the offset of the fourth profile of the thin-walled part, and take effect when the number of profiles is set to 1, 2, 3 and 4 respectively.

[0058] The X / Y fill offset (fill offset for short) is the offset of the end point of the fill scan line relative to the nominal contour of the part.

[0059] Nominal part profile: The size given by the design, that is, the theoretical position of the part profile.

[0060] The parameter contour quantity setting value is 1, that is, the contour scanning times are set to 1, which means that only one contour is printed for the part, and the offset value is only effective for the first offset set (the setting value of contour offset 1). If the requirements are met, only scanning once can also save printing time.

[0061] When printing parts, there are filling and contour scanning. When the contour offset value is a positive number, it means the offset is towards the inside of the workpiece. The larger the value, the greater the offset. When the association changes, the larger the contour offset value, the smaller the fill offset value, and finally there will be no fill. Contour offset 2, contour offset 3, contour offset 4 and fill offset are all the associated change values ​​of contour offset 1. The main function of the associated change is to ensure that the relative position between contour and fill remains unchanged.

[0062] When forming the internal solid part of a part, the filling parameters (filling bias) need to be optimized. Because the spot size of the equipment is 70-90μm and the wall thickness of the part is 0.2-0.4mm, the wall thickness of the part can be close to the required size by simply scanning the laser spot along the contour of the model. If the filling parameters are turned on, the energy dissipated during the sintering of the internal solid will also cause the surrounding powder to semi-melt, and the wall thickness will exceed the required size.

[0063] The 3D printing equipment has upper surface contour scanning parameters, lower surface contour scanning parameters and standard contour scanning parameters. In order to distinguish them from the contour parameters of the other two special positions, the standard contour scanning parameters are actually ordinary contour scanning parameters, which are the power and speed of laser scanning when the external contour of the part is formed.

[0064] The laser power of the standard profile scanning parameters is set to 180-250W, the scanning speed is set to 800-1000mm / s, and the spot size is set to 70-90μm. Before printing, the powder scraper is leveled to a distance of no more than 0.05mm from the substrate, the substrate preheating temperature is set to 80-120℃, and the wind pressure is set to 270-320Pa.

[0065] Preferably, the laser power of the standard profile scanning parameters is set to 180W, the scanning speed is set to 800mm / s, and the spot size is set to 90μm. Before printing, the powder spreading scraper is leveled to a distance of no more than 0.05mm from the substrate, the substrate preheating temperature is set to 100°C, and the wind pressure is set to 300Pa.

[0066] High-purity argon gas with a purity of at least 99.99% must be introduced into the processing chamber of the 3D printing equipment as a protective gas. 3D printing processing can only be officially carried out when the oxygen content in the processing chamber is less than 0.1%.

[0067] The specific metal powder material used for printing and manufacturing parts is 15-53μm Permalloy Fe-Ni50.

[0068] Step 4: After printing is completed, the thin-walled parts are cleaned out of the 3D printing equipment and cut off from the substrate to obtain the printed Permalloy thin-walled parts.

[0069] After printing is completed, the parts are cleaned out of the 3D printing equipment and air-cooled (cooled in the air). After air-cooling, they are cut from the substrate to obtain the required printed Permalloy thin-walled parts.

[0070] In this embodiment, permalloy Fe-Ni50 is used as an example to print thin-walled parts, and the shape is a regular hexagonal honeycomb hole, such as Figure 2-Figure 4 shown.

[0071] In order to test whether the printing parameters of this embodiment meet the mechanical property requirements for printing parts, samples within the GB / T228 metal tensile standard are selected for printing and testing. The mechanical property results are shown in Table 1 below.

[0072] Table 1 Comparison of mechanical properties results

[0073]

[0074] From the test results shown in Table 1, it can be concluded that the tensile strength and elongation results measured in Table 1 when the printing parameters provided in this embodiment are used for printing meet the use requirements. Using the printing parameters provided in this embodiment for part printing can ensure that the strength of the molded parts meets the requirements, meets the required mechanical properties, and ensures that the size of the thin wall meets the requirements.

[0075] The honeycomb hole parts were 3D printed using the part printing parameters that met the requirements, and the wall thickness was measured using a measuring tool to obtain the comparison table of thin-walled parts forming results shown in Table 2.

[0076] Table 2 Comparison of thin-walled parts forming results

[0077]

[0078] As can be seen from Table 2, the thin-walled part obtained by No. 6 was not formed, the thin-walled parts of No. 1 and No. 4 had holes, and the thin-walled parts of No. 2, No. 3 and No. 5 were successfully formed and the wall thickness met the requirements, but there were teeth on the top. By comparing the thin-walled parts obtained by No. 4 and No. 5, it was found that reducing the power can improve the tooth condition and is conducive to the forming of the top position. Energy density is the energy applied to a unit volume of material, which is power / speed. When the energy density of the parameters is close, the mechanical properties of the thin-walled parts are close. The energy density of power 180W and speed 800mm / s is similar to that of power 220W and speed 1000mm / s. The mechanical properties of the thin-walled parts formed using power 180W and speed 800mm / s also meet the use requirements.

[0079] By adopting the method for 3D printing Permalloy thin-walled parts provided in this embodiment, the residual stress and cracking problems of the parts are solved from the perspective of molding process parameters, and thin-walled parts with mechanical properties and wall thickness that meet the use requirements are obtained.

[0080] By adopting the printing method of this embodiment, the wall thickness dimensional accuracy of the thin-walled parts can reach ±0.05mm, the tensile strength is ≥500MPa, and the elongation is ≥35%.

[0081] The printing process parameters improved the printing success rate and processing efficiency of 3D printing of Permalloy Fe-Ni50 thin-walled parts, successfully completed the 3D printing processing task of Permalloy Fe-Ni50 thin-walled parts, and reduced production costs and time costs for customers while ensuring the 3D printing processing quality of parts.

[0082] Those skilled in the art will appreciate that the features described in the various embodiments and / or claims of the present application may be combined and / or combined in a variety of ways, even if such combinations and / or combinations are not explicitly described in the present application. In particular, without departing from the spirit and teachings of the present application, the technical features described in the various embodiments and / or claims of the present application may be combined and / or combined in a variety of ways, and all of these combinations and / or combinations fall within the scope of the present application.

[0083] Although the present application has been shown and described with reference to specific exemplary embodiments of the present application, it should be understood by those skilled in the art that various changes in form and details may be made to the present application without departing from the spirit and scope of the present application as defined by the appended claims and their equivalents. Therefore, the scope of the present application should not be limited to the above-mentioned embodiments, but should be determined not only by the appended claims, but also by the equivalents of the appended claims.

Claims

1. A 3D printing method for Permalloy thin-walled parts, characterized in that: include: Perform three-dimensional modeling of thin-walled parts, perform data processing on the constructed three-dimensional model, and obtain the processed three-dimensional model; Import the processed 3D model into the slicing software of the 3D printing device for slicing and printing path planning, set the placement and processing direction of thin-walled parts, and generate the printing program; Setting the placement and processing direction of thin-walled parts includes: The placement direction relative to the printing chamber of the 3D printing device is to place the parts in sequence from the position close to the powder supply cylinder, and the thin-walled parts are placed vertically relative to the base plate; The processing direction is to print and shape in sequence from the air suction port to the air blowing port; The printing parameters are set so that the three-dimensional model has no filling parameters and only retains the standard contour scanning parameters when slicing, and the thin-walled parts are 3D printed based on the printing program; the printing parameter setting method of the three-dimensional model having no filling parameters and only retaining the standard contour scanning parameters when slicing includes: The first contour offset value in the contour offset parameters is set to 0.07-0.09 mm and changed in association; The value range of the second contour offset value is: 0.11-0.13 mm; The value range of the third contour offset value is: 0.14-0.16 mm; The fourth contour offset value range is: 0.17-0.19 mm; The second to fourth contour offset values ​​are obtained by changing the first contour offset value in association; After printing is completed, the thin-walled parts are cleaned out of the 3D printing equipment and cut off from the substrate to obtain the printed Permalloy thin-walled parts.

2. The 3D printing method according to claim 1, characterized in that: The first profile offset value is set to 0.09 mm; The second to fourth profile offset values ​​are respectively taken as follows: 0.13 mm, 0.16 mm and 0.19 mm.

3. The 3D printing method according to claim 1 or 2, characterized in that: The parameters that need to be set when printing include: The profile scanning power was set to 180-250 W; the profile scanning speed was set to 800-1000 mm / s; The spot size was set to 70-90 μm; the powder spreading scraper was leveled to a distance of no more than 0.05 mm from the substrate; the substrate preheating temperature was set to 80-120 °C; the wind pressure was set to 270-320 Pa; a layer thickness of 0.03-0.04 mm was used for printing; and the number of contour scans was set to 1.

4. The 3D printing method according to claim 3, characterized in that: The profile scanning power was set to 180 W; the profile scanning speed was set to 800 mm / s; The spot size was set to 90 μm; the substrate preheating temperature was set to 100 °C; the wind pressure was set to 300 Pa; and the layer thickness was 0.04 mm for printing.

5. The 3D printing method according to claim 1, wherein: Before 3D printing thin-walled parts, it also includes: High-purity argon gas with a purity of at least 99.99% is introduced into the processing chamber of the 3D printing equipment as a protective gas, and 3D printing can only be performed when the oxygen content in the processing chamber is less than 0.1%.

6. The 3D printing method according to claim 1, characterized in that: The wall thickness of the printed Permalloy thin-walled parts ranges from 0.2-0.4 mm.

7. The 3D printing method according to claim 6, characterized in that: The metal powder material used for printing thin-walled parts is 15-53μm Permalloy Fe-Ni50.

8. The 3D printing method according to claim 6 or 7, characterized in that: The printed Permalloy thin-walled parts have an overall hexagonal honeycomb shape.

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