A method for determining scanning melting energy in additive manufacturing

Abstract

The present application relates to a method for determining scanning melting energy for additive manufacturing. The method comprises: determining the standard melting energy input of a three-dimensional object based on standard scanning power, standard scanning speed, standard scanning line spacing, standard scanning resolution, and layer thickness; using the standard melting energy input to melt the three-dimensional object, defining the first scanning line length corresponding to when the current layer's two-dimensional cross section just experiences over-melting as the first critical value of the first scanning line length; defining the first scanning line length that is less than the first critical value of the first scanning line length as the second scanning line length, and defining the two-dimensional cross section melted using the second scanning line length as a small-size cross section. Through the present application, the over-melting phenomenon of small-size cross sections and the under-melting phenomenon of over-small-size cross sections can be avoided, thereby improving the forming quality of special-shaped parts.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of additive manufacturing technology, and in particular to a method for determining scanning melting energy in additive manufacturing. Background Art

[0002] Electron beam selective melting (EBM) is an additive manufacturing technology that uses an electron beam to melt metal powder layer by layer to create three-dimensional parts. The process involves laying a layer of powder on a preheated substrate. The powder is then preheated. Based on the two-dimensional cross-sectional information of the part to be formed, the electron beam selectively scans the preheated powder point by point in parallel lines, melting the preheated powder to complete the current layer. These steps are repeated until the additive manufacturing of the three-dimensional part is complete. However, using the same melting process, when melting small cross-sections, overmelting can occur, affecting the subsequent powder laying process and leading to melting quality issues, or even causing printing to be terminated.

[0003] In the related art, the energy required to melt parts of different sizes is controlled by the required melting process based on the scan line length: the area with smaller two-dimensional cross-sectional dimensions corresponds to a shorter scan line length. Considering that the heat input required to melt the powder layer is relatively low, time slots are set before and after the scan line when melting small-sized areas. The energy beam during the time slot is used to melt other areas or preheat the powder bed; or the spacing between adjacent scan lines is adjusted according to the length of at least one of the two adjacent scan lines, thereby controlling the heat input of the two-dimensional cross-sectional areas of different sizes to fuse the powder layer and avoid over-melting caused by overheating of small-sized parts. The above-mentioned related art only considers the energy input required to melt the powder layer for the over-melting phenomenon of small-sized cross-sectional parts. This is applicable to the melting of powder layers within a given size range. However, for cross-sectional areas with too small dimensions, the energy required to melt the powder layer itself is small, so heat dissipation considerations during the melting process are also very important.

[0004] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0006] The purpose of the embodiments of the present application is to provide a method for determining scanning melting energy in additive manufacturing, thereby overcoming one or more problems caused by the limitations and defects of related technologies, at least to a certain extent.

[0007] According to an embodiment of the present application, a method for determining scanning melting energy for additive manufacturing is provided, the method comprising:

[0008] Determine the standard melting energy input for a three-dimensional object based on standard scanning power, standard scanning speed, standard scanning line spacing, standard scanning resolution, and layer thickness;

[0009] The three-dimensional object is melted by using the standard melting energy input, and a first scanning line length corresponding to when an overmelting phenomenon just occurs in a two-dimensional cross section of a current layer is defined as a first critical value of the first scanning line length;

[0010] defining a first scan line length smaller than a first critical value of the first scan line length as a second scan line length, and defining a two-dimensional cross section melted by the second scan line length as a small-size cross section;

[0011] determining a melting energy input for the small-size cross-section according to a scanning power at the second scanning line length, a scanning line spacing at the second scanning line length, a scanning resolution at the second scanning line length, the standard scanning speed, and the layer thickness;

[0012] The three-dimensional object is melted using the melting energy input of the small-sized cross-section, and the second scanning line length corresponding to when the current two-dimensional cross-section just experiences undermelting is defined as a second critical value of the first scanning line length; wherein the second critical value of the first scanning line length is less than the first critical value of the first scanning line length;

[0013] defining a second scan line length smaller than a second critical value of the first scan line length as a third scan line length, and defining a two-dimensional cross section melted by the third scan line length as a small-size cross section;

[0014] When the undersized cross section is in a square shape, energy compensation is performed on the melting energy input of the undersized cross section, and the melting energy input of the undersized cross section after energy compensation is determined as the melting energy input of the square undersized cross section;

[0015] When the shape of the undersized cross section is a rectangle, the melting energy input of the undersized cross section is determined as the melting energy input of the rectangular undersized cross section.

[0016] In one embodiment of the present application, the calculation formula of the standard melting energy input is as follows:

[0017] (1)

[0018] Where, represents the standard melting energy input, the subscript No actual physical meaning. Indicates the standard scanning power, Indicates the standard scanning speed, Indicates layer thickness, Indicates the standard scan line spacing, Indicates standard scanning resolution.

[0019] In one embodiment of the present application, the calculation formula for the melting energy input of the small-sized cross-section is as follows:

[0020] (2)

[0021] Where, Indicates the melting energy input of the small cross section, the subscript No actual physical meaning. represents the length of the second scan line, represents the scanning power under the second scanning line length, represents the scan line spacing under the second scan line length, Indicates the scanning resolution under the second scanning line length, represents a decreasing function of the scanning power at the second scanning line length, the scanning line spacing at the second scanning line length, and the scanning resolution at the second scanning line length with respect to the second scanning line length, Indicates the standard scanning speed, Indicates layer thickness.

[0022] In one embodiment of the present application, the calculation formula for the scanning power at the second scanning line length is as follows:

[0023] (3)

[0024] The calculation formula of the scan line spacing under the second scan line length is as follows:

[0025] (4)

[0026] The calculation formula for the scanning resolution under the second scanning line length is as follows:

[0027] (5)

[0028] Where, represents the first critical value of the first scan line length, ≥1, Indicates the standard scanning power, Indicates the standard scan line spacing, Indicates standard scanning resolution.

[0029] In one embodiment of the present application, the side length of the square undersized cross-section is 1 third scan line length, the short side of the rectangular undersized cross-section is 1 third scan line length, and the long side is n third scan line lengths, where n is a number greater than 1.

[0030] In one embodiment of the present application, the calculation formula for the melting energy input of the square undersized cross section is as follows:

[0031] (6)

[0032] In the formula, the subscript No actual physical meaning. represents the length of the second scan line, represents the melting energy input for a square undersized cross section, represents the melting energy input of a small cross-section, Indicates compensation energy, superscript No actual physical meaning.

[0033] In one embodiment of the present application, the compensation energy is determined by the heat dissipation of the undersized cross-section of the square.

[0034] In one embodiment of the present application, the calculation formula of the compensation energy is as follows:

[0035] (7)

[0036] Where, represents the horizontal direction of the undersized square section on the two-dimensional plane, represents the vertical direction of the undersized square section on the two-dimensional plane, Indicates that the square is undersized. The direction component, Indicates that the square is undersized. The direction component, Indicates that the square is undersized. The heat dissipation of the layer thickness in the direction, Indicates that the square is undersized. The amount of heat dissipated by the layer thickness in the direction.

[0037] In one embodiment of the present application, the undersized cross section of the square is The calculation formula for the heat dissipation of the layer thickness in the direction is as follows:

[0038] (8)

[0039] The undersized section of the square is The calculation formula for the heat dissipation of the layer thickness in the direction is as follows:

[0040] (9)

[0041] Where, Indicates the thermal conductivity of the printing material, Indicates layer thickness, represents the melt pool temperature, Indicates that the square is undersized. The heat dissipation of the layer thickness in the direction, Indicates that the square is undersized. The amount of heat dissipated by the layer thickness in the direction.

[0042] The technical solutions provided by the embodiments of the present application may have the following beneficial effects:

[0043] In an embodiment of the present application, the first scan line length corresponding to when the current two-dimensional cross-section just experiences overmelting is defined as the first critical value of the first scan line length by the above method. The second scan line length is then determined based on the first critical value of the first scan line length, and the undersized cross-section is determined based on the second scan line length. The melting energy input for the undersized cross-section is determined based on the second scan line length, and the undersized cross-section is melted using the melting energy input of the undersized cross-section to avoid overmelting of the undersized cross-section. The second scan line length corresponding to when the current two-dimensional cross-section just experiences undermelting is defined as the second critical value of the first scan line length. The third scan line length is then determined based on the second critical value of the first scan line length, and the undersized cross-section is determined based on the third scan line length. When the undersized cross-section is square, the melting energy input for the undersized cross-section is energy compensated, and the energy-compensated melting energy input for the undersized cross-section is determined as the melting energy input for the square undersized cross-section. When the undersized cross-section is rectangular, the melting energy input for the undersized cross-section is determined as the melting energy input for the rectangular undersized cross-section. By comprehensively considering the length of the third scanning line and the heat loss during the undersized melting process, undermelting of undersized cross-sections is avoided, thereby solving the melting quality problem of undersized cross-sections. This application can avoid overmelting of undersized cross-sections and undermelting of undersized cross-sections, thereby improving the forming quality of special-shaped parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0045] Figure 1 A flowchart showing the steps of a method for determining scanning melting energy for additive manufacturing in an exemplary embodiment of the present application is provided;

[0046] Figure 2 A schematic diagram showing the components of a square undersized cross section in a two-dimensional plane in an exemplary embodiment of the present application;

[0047] Figure 3 Showing pictures of sample parts with large and small cross sections printed using standard melting energy input in an exemplary embodiment of the present application;

[0048] Figure 4 Showing images of sample parts with small cross-sections printed using standard melting energy input and images of sample parts with small cross-sections and oversized cross-sections printed using a second scan line length of less than 10 mm in an exemplary embodiment of the present application;

[0049] Figure 5 Showing sample images of small-sized cross sections and over-small-sized cross sections printed using a second scan line length of less than 10 mm in an exemplary embodiment of the present application;

[0050] Figure 6 A picture of a sample of a square undersized cross section printed using a compensated undersized cross section melting energy input in an exemplary embodiment of the present application is shown;

[0051] Figure 7 A sample picture of a small-sized cross-section printed using a second scan line length less than 10 mm and a sample picture of an overly small-sized cross-section printed using a third scan line length in an exemplary embodiment of the present application are shown. DETAILED DESCRIPTION

[0052] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0053] In addition, the accompanying drawings are merely schematic illustrations of embodiments of the present application and are not necessarily drawn to scale. Identical reference numerals in the drawings represent identical or similar parts, and thus repeated descriptions thereof will be omitted. Some of the blocks shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0054] This example embodiment provides a method for determining scanning melting energy for additive manufacturing. Figure 1 As shown in , the method includes: steps S101 to S108.

[0055] Wherein, step S101: determining a standard melting energy input of a three-dimensional object according to a standard scanning power, a standard scanning speed, a standard scanning line spacing, a standard scanning resolution and a layer thickness.

[0056] Step S102: melt the three-dimensional object using a standard melting energy input, and define the first scanning line length corresponding to when the current two-dimensional cross section just experiences over-melting as a first critical value of the first scanning line length.

[0057] Step S103: defining a first scan line length that is smaller than a first critical value of the first scan line length as a second scan line length, and defining a two-dimensional cross section melted by using the second scan line length as a small-size cross section.

[0058] Step S104: determining the melting energy input of the small-size cross section according to the scanning power at the second scanning line length, the scanning line spacing at the second scanning line length, the scanning resolution at the second scanning line length, the standard scanning speed, and the layer thickness.

[0059] Step S105: Use melting energy input of a small-sized cross-section to melt the three-dimensional object, and define the second scan line length corresponding to when the current layer of the two-dimensional cross-section just undergoes under-melting as the second critical value of the first scan line length; wherein the second critical value of the first scan line length is less than the first critical value of the first scan line length.

[0060] Step S106: defining a second scan line length that is smaller than a second critical value of the first scan line length as a third scan line length, and defining a two-dimensional cross section melted by the third scan line length as an undersized cross section.

[0061] Step S107: When the undersized cross section is a square, energy compensation is performed on the melting energy input of the undersized cross section, and the melting energy input of the undersized cross section after energy compensation is determined as the melting energy input of the square undersized cross section.

[0062] Step S108: When the shape of the undersized cross section is a rectangle, the melting energy input of the undersized cross section is determined as the melting energy input of the rectangular undersized cross section.

[0063] In an embodiment of the present application, the above method defines the first scan line length corresponding to when the current two-dimensional cross-section just experiences overmelting as the first critical value of the first scan line length. A second scan line length is determined based on the first critical value of the first scan line length, and the undersized cross-section is determined based on the second scan line length. The melting energy input of the undersized cross-section is determined based on the second scan line length, and the undersized cross-section is melted using the melting energy input of the undersized cross-section to avoid overmelting of the undersized cross-section. The second scan line length corresponding to when the current two-dimensional cross-section just experiences undermelting is defined as the second critical value of the first scan line length. A third scan line length is determined based on the second critical value of the first scan line length, and the undersized cross-section is determined based on the third scan line length. When the undersized cross-section is square, energy compensation is performed on the melting energy input of the undersized cross-section, and the energy-compensated melting energy input of the undersized cross-section is determined as the melting energy input of the square undersized cross-section. When the undersized cross-section is rectangular, the melting energy input of the undersized cross-section is determined as the melting energy input of the rectangular undersized cross-section. By comprehensively considering the length of the third scanning line and the heat loss during the undersized melting process, undermelting of undersized cross-sections is avoided, thereby solving the melting quality problem of undersized cross-sections. This application can avoid overmelting of undersized cross-sections and undermelting of undersized cross-sections, thereby improving the forming quality of special-shaped parts.

[0064] Below, we will refer to Figures 1 to 2 Each step of the above-mentioned method for determining scanning melting energy for additive manufacturing in this example embodiment is described in more detail.

[0065] In step S101, when printing a three-dimensional object, the standard melting energy input is generally related to the standard scanning power, standard scanning speed, standard scanning line spacing, standard scanning resolution, and layer thickness. Therefore, the standard melting energy input can be calculated based on the standard scanning power, standard scanning speed, standard scanning line spacing, standard scanning resolution, and layer thickness.

[0066] Furthermore, the calculation formula for the standard melting energy input is as follows:

[0067] (1)

[0068] Where, represents the standard melting energy input, the subscript No actual physical meaning. Indicates the standard scanning power, Indicates the standard scanning speed, Indicates layer thickness, Indicates the standard scan line spacing, Indicates standard scanning resolution.

[0069] It can be understood that by calculating the standard melting energy input , which facilitates the use of standard melting energy input During the melting of the three-dimensional object, a first critical value of the first scanning line length is determined.

[0070] In step S102, the standard melting energy input In the process of melting a three-dimensional object, the standard melting energy input calculated above is Melting facilitates determining the applicable lower limit of the first scan line length (ie, the first critical value of the first scan line length).

[0071] Because the three-dimensional object is a special-shaped part, the size of the two-dimensional cross-section of different layers will change. During the melting of the three-dimensional object, the first scanning line length corresponding to when the current two-dimensional cross section just experiences over-melting is defined as a first critical value of the first scanning line length.

[0072] When the first scanning line length is greater than or equal to the first critical value of the first scanning line length, the standard melting energy input is used. It can ensure that the two-dimensional cross-sectional area of ​​a single layer thickness is completely melted and formed without overmelting.

[0073] In step S103 , the applicable rule of the powder bed electron beam melting process is: the melting and forming of a large-sized two-dimensional cross-section requires a relatively large melting energy input, while the melting and forming of a small-sized cross-section requires a relatively small melting energy input.

[0074] In this application, the first scan line length which is less than the first critical value of the first scan line length is defined as the second scan line length. , and the second scan line length will be used The melted two-dimensional cross section is defined as the small-size cross section.

[0075] Similarly, a two-dimensional cross section melted by a first scan line length greater than or equal to the first critical value of the first scan line length is defined as a large-size cross section. For a large-size cross section, a first scan line length greater than or equal to the first critical value of the first scan line length is used for melting. When the first scan line length is greater than or equal to the first critical value of the first scan line length, the standard melting energy input is used. It can ensure that large cross-sectional areas with a single layer thickness are completely melted and formed without overmelting.

[0076] In step S104, after defining the second scan line length After determining the small-sized cross-section, the present application needs to further determine the melting energy input for melting the small-sized cross-section, so as to melt the small-sized cross-section by the melting energy input of the small-sized cross-section. Specifically, the present application can determine the melting energy input of the small-sized cross-section by the scanning power at the second scanning line length, the scanning line spacing at the second scanning line length, the scanning resolution at the second scanning line length, the standard scanning speed, and the layer thickness of the small-sized cross-section.

[0077] Furthermore, the calculation formula for the melting energy input of a small-size cross-section is as follows:

[0078] (2)

[0079] Where, Indicates the melting energy input of the small cross section, the subscript No actual physical meaning. represents the length of the second scan line, represents the scanning power under the second scanning line length, represents the scan line spacing under the second scan line length, Indicates the scanning resolution under the second scanning line length, represents a decreasing function of the scanning power at the second scanning line length, the scanning line spacing at the second scanning line length, and the scanning resolution at the second scanning line length with respect to the second scanning line length, Indicates the standard scanning speed, Indicates layer thickness.

[0080] It can be understood that from formula (2) it can be seen that when the second scan line length The smaller the The smaller the value, the smaller the melting energy input of the cross section. The smaller.

[0081] Furthermore, the calculation formula for the scanning power under the second scanning line length is as follows:

[0082] (3)

[0083] The calculation formula for the scan line spacing under the second scan line length is as follows:

[0084] (4)

[0085] The calculation formula for the scanning resolution under the second scanning line length is as follows:

[0086] (5)

[0087] Where, represents the first critical value of the first scan line length, ≥1, Indicates the standard scanning power, Indicates the standard scan line spacing, Indicates standard scanning resolution.

[0088] It can be understood that from formula (3) it can be seen that the length of the second scanning line The smaller it is, the smaller the corresponding scanning power is. From formula (4), it can be seen that the length of the second scanning line is The smaller it is, the corresponding scan line spacing is the same as the standard scan line spacing, or the corresponding scan line spacing is smaller. From formula (5), it can be seen that the second scan line length The smaller it is, the corresponding scanning resolution is the same as the standard scanning resolution, or the corresponding scanning resolution is smaller.

[0089] In step S105, the melting energy input is In the process of melting a three-dimensional object, the melting energy input of a small cross section calculated by the above formula (2) is , which facilitates determining the applicable lower limit of the first critical value of the first scan line length (ie, the second critical value of the first scan line length).

[0090] This application uses a small cross-section melting energy input In the process of melting a three-dimensional object, the length of the second scanning line corresponding to the undermelting phenomenon of the current two-dimensional cross section is A second critical value defined as the length of the first scan line.

[0091] In step S106, step S107 and step S108, the present application sets a second scan line length smaller than a second critical value of the first scan line length to The third scanning line length is defined as the third scanning line length, and the two-dimensional cross section melted by using the third scanning line length is defined as an undersized cross section.

[0092] When the third scanning line length is less than the second critical value of the first scanning line length, the melting energy input of the small-sized cross section is input into the oversized cross section. When melting a three-dimensional object, the shape of the undersized cross-section can be in the following two situations:

[0093] The first case: When the shape of the undersized cross section is a square, the melting energy input of the undersized cross section is used. When melting a square cross-section that is too small, a void undermelting defect will occur, which means that the melting energy input of the small cross-section is too small. Not enough to melt a square undersized section.

[0094] When the undersized cross section is rectangular, the melting energy input of the undersized cross section is used. When melting a rectangular cross-section that is too small, it can be melted normally without void undermelting defects, that is, the melting energy input of the small cross-section is Rectangular undersized sections can be melted.

[0095] It should be noted that when the shape of the undersized cross-section is a rectangle, the melting energy input of the undersized cross-section is determined as the melting energy input of the rectangular undersized cross-section, which means that the melting energy input of the rectangular undersized cross-section is calculated according to the above formula (2) for calculating the melting energy input of the undersized cross-section.

[0096] Furthermore, the side length of the undersized square section satisfies the following conditions:

[0097] The side length of the square undersized cross section is 1 third scan line length.

[0098] The side lengths of the rectangular undersized section satisfy the following conditions:

[0099] The short side of the rectangular undersized cross section is 1 third scan line length, and the long side is n third scan line lengths, where n is a number greater than 1.

[0100] Furthermore, the calculation formula for the melting energy input of a square undersized cross section is as follows:

[0101] (6)

[0102] In the formula, the subscript It has no actual physical meaning. represents the length of the second scan line, represents the melting energy input for a square undersized cross section, represents the melting energy input of a small cross-section, Indicates compensation energy, superscript No actual physical meaning.

[0103] It can be understood that when the shape of the undersized cross section is a square, the melting energy input of the undersized cross section is It is not enough to melt the undersized square cross section. Because for the undersized square cross section, when the length of the third scanning line is constant, the smaller the area of ​​the undersized square cross section is, the smaller the melting energy input of the small cross section calculated according to the above formula (2) is. At this time, the influence of the heat conduction loss factor in the melting forming process cannot be ignored. Therefore, it is necessary to compensate for the melting energy input of the small cross section on the basis of considering the heat loss to ensure the melting forming of the undersized square cross section.

[0104] Specifically, the compensation of melting energy input of small-sized cross-sections can be achieved through formula (6).

[0105] Furthermore, the compensation energy is determined by the heat dissipation of the square undersized cross section.

[0106] In one embodiment, the calculation formula of the compensation energy is as follows:

[0107] (7)

[0108] Where, represents the horizontal direction of the undersized square section on the two-dimensional plane, represents the vertical direction of the undersized square section on the two-dimensional plane, Indicates that the square is undersized. The direction component, Indicates that the square is undersized. The direction component, Indicates that the square is undersized. The heat dissipation of the layer thickness in the direction, Indicates that the square is undersized. The amount of heat dissipated by the layer thickness in the direction.

[0109] It can be understood that the compensation energy can be calculated according to Formula 7. Figure 2 As shown, the x-direction component of the undersized square cross section in the two-dimensional plane is , the undersized square cross section in the two-dimensional plane Directional component .

[0110] Furthermore, the undersized square section The calculation formula for the heat dissipation of the layer thickness in the direction is as follows:

[0111] (8)

[0112] The undersized square section The calculation formula for the heat dissipation of the layer thickness in the direction is as follows:

[0113] (9)

[0114] Where, Indicates the thermal conductivity of the printing material, Indicates layer thickness, represents the melt pool temperature, Indicates that the square is undersized. The heat dissipation of the layer thickness in the direction, Indicates that the square is undersized. The amount of heat dissipated by the layer thickness in the direction.

[0115] It is understandable that the undersized square section The heat dissipation of the layer thickness in the direction is related to the thermal conductivity of the printing material and the temperature of the molten pool. Specifically, the square undersized cross section can be calculated by formula (8) The amount of heat dissipated by the layer thickness in the direction.

[0116] The undersized square section The heat dissipation of the layer thickness in the direction is related to the thermal conductivity of the printing material and the temperature of the molten pool. Specifically, the square undersized cross section can be calculated by formula (9). The amount of heat dissipated by the layer thickness in the direction.

[0117] It should be noted that, in the present application, the first critical value of the length of the first scanning line is generally between 10-15 mm, and the second critical value of the length of the first scanning line is generally between 4-8 mm.

[0118] The present application will be further described below through Example 1.

[0119] It should be noted that, in the process of printing special-shaped parts, the present application has large-sized cross-sections, small-sized cross-sections, and undersized cross-sections. In order to facilitate the observation of the melting conditions of two-dimensional cross-sections of different sizes, the present application prints samples of two-dimensional cross-sections of each size, that is, the present application prints samples of large cross-sections according to the specifications of large cross-sections, prints samples of small cross-sections according to the specifications of small cross-sections, and prints samples of undersized cross-sections according to the specifications of undersized cross-sections.

[0120] Example 1:

[0121] Standard melting process: standard scanning power is 16mA, standard scanning speed is 5m / s, standard scanning resolution is 0.1mm, standard scanning line spacing is 0.1mm, and layer thickness is 0.05mm.

[0122] Take printing TC4 samples as an example.

[0123] Printing large-size cross-section samples, the length of the first scanning line of the large-size cross-section is greater than or equal to 10mm, by using formula (1) and the above standard melting process to calculate the standard melting energy input, and use the calculated standard melting energy input to print large-size cross-section samples. Figure 3 It can be seen from the first row that the surface of the sample with large cross-section is smooth and the forming quality is good.

[0124] Printing small cross-section samples, using the above standard melting energy input to print small cross-section samples, from Figure 3 The second line, and from Figure 4 It can be seen from the first row that the center of the surface of the printed sample with a small cross-section is convex and over-melting occurs. The first scanning line length corresponding to the over-melting phenomenon when printing the sample with a small cross-section is used as the first critical value of the first scanning line length. The first critical value of the first scanning line length is 10mm.

[0125] This application uses a second scanning line length of less than 10mm to print small-size cross-section samples. Figure 4 From the first three samples from the left in the second row, we can see that the surface of the printed small-size cross-section samples is smooth and the forming quality is good; Figure 5 From the first two samples from the left in the middle, we can see that the surface of the printed small-size cross-section samples is smooth and the forming quality is good. Figure 4 From the last three samples in the second row from the left, we can see that the surface of the printed square samples with undersized cross-sections is uneven and under-melted, indicating poor forming quality. Figure 5 From the last two samples from the middle left, it can be seen that the printed rectangular samples with undersized cross-sections have uneven surfaces and are under-melted, resulting in poor forming quality.

[0126] In the process of printing samples with small cross-sections using a second scan line length of less than 10 mm, the second scan line length corresponding to when under-melting occurs in the process of printing samples with too small cross-sections is used as the second critical value of the first scan line length. The second critical value of the first scan line length is 5 mm, and the second scan line length less than 5 mm is used as the third scan line length.

[0127] Printing samples with undersized cross-sections. When the shape of the undersized cross-section is a square, the melting energy input of the compensated small cross-section is used to print the square undersized cross-section sample. Figure 6 It can be seen from the figure that the surface of the printed square undersized cross-section sample is smooth and has no undermelting phenomenon, and the forming quality is good.

[0128] The melting energy input of the compensated undersized cross section, that is, the melting energy input of the square undersized cross section, can be calculated according to formula (6).

[0129] When printing a sample with an undersized cross-section, if the shape of the undersized cross-section is a rectangle, the melting energy input of the undersized cross-section is determined as the melting energy input of the rectangular undersized cross-section. That is, the melting energy input of the undersized cross-section is calculated using formula (2). Figure 7From the last two samples from the left, it can be seen that the printed rectangular undersized cross-section samples have a smooth surface and no undermelting phenomenon, and the forming quality is good.

[0130] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0131] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of this application and include common knowledge or customary techniques in the art that are not disclosed herein.

Claims

1. A method for determining scanning melting energy in additive manufacturing, characterized in that: The method includes: Determine the standard melting energy input for a three-dimensional object based on standard scanning power, standard scanning speed, standard scanning line spacing, standard scanning resolution, and layer thickness; The three-dimensional object is melted by using the standard melting energy input, and a first scanning line length corresponding to when an overmelting phenomenon just occurs in a two-dimensional cross section of a current layer is defined as a first critical value of the first scanning line length; defining a first scan line length smaller than a first critical value of the first scan line length as a second scan line length, and defining a two-dimensional cross section melted by the second scan line length as a small-size cross section; determining a melting energy input for the small-size cross-section according to a scanning power at the second scanning line length, a scanning line spacing at the second scanning line length, a scanning resolution at the second scanning line length, the standard scanning speed, and the layer thickness; The three-dimensional object is melted using the melting energy input of the small-sized cross-section, and the second scanning line length corresponding to when the current two-dimensional cross-section just experiences undermelting is defined as a second critical value of the first scanning line length; wherein the second critical value of the first scanning line length is less than the first critical value of the first scanning line length; defining a second scan line length that is smaller than a second critical value of the first scan line length as a third scan line length, and defining a two-dimensional cross section melted by the third scan line length as an undersized cross section; When the undersized cross section is in a square shape, energy compensation is performed on the melting energy input of the undersized cross section, and the melting energy input of the undersized cross section after energy compensation is determined as the melting energy input of the square undersized cross section; When the shape of the undersized cross section is a rectangle, the melting energy input of the undersized cross section is determined as the melting energy input of the rectangular undersized cross section.

2. The scanning melting energy determination method for additive manufacturing according to claim 1, characterized in that: The calculation formula of the standard melting energy input is as follows: （1） Where, represents the standard melting energy input, the subscript No actual physical meaning. Indicates the standard scanning power, Indicates the standard scanning speed, Indicates layer thickness, Indicates the standard scan line spacing, Indicates standard scanning resolution.

3. The scanning melting energy determination method for additive manufacturing according to claim 1, characterized in that: The calculation formula for the melting energy input of the small-size cross-section is as follows: （2） Where, Indicates the melting energy input of the small cross section, the subscript No actual physical meaning. represents the length of the second scan line, represents the scanning power under the second scanning line length, represents the scan line spacing under the second scan line length, Indicates the scanning resolution under the second scanning line length, represents a decreasing function of the scanning power at the second scanning line length, the scanning line spacing at the second scanning line length, and the scanning resolution at the second scanning line length with respect to the second scanning line length, Indicates the standard scanning speed, Indicates layer thickness.

4. The scanning melting energy determination method for additive manufacturing according to claim 3, characterized in that: The calculation formula of the scanning power under the second scanning line length is as follows: （3） The calculation formula of the scan line spacing under the second scan line length is as follows: （4） The calculation formula for the scanning resolution under the second scanning line length is as follows: （5） Where, represents the first critical value of the first scan line length, ≥1, Indicates the standard scanning power, Indicates the standard scan line spacing, Indicates standard scanning resolution.

5. The method for determining scanning melting energy for additive manufacturing according to claim 1, wherein: The side length of the undersized square section is 1 third scan line length, the short side of the undersized rectangular section is 1 third scan line length, and the long side is n third scan line lengths, where n is a number greater than 1.

6. The method for determining scanning melting energy for additive manufacturing according to claim 5, characterized in that: The calculation formula for the melting energy input of the square undersized cross section is as follows: （6） In the formula, the subscript No actual physical meaning. represents the length of the second scan line, represents the melting energy input for a square undersized cross section, represents the melting energy input of a small cross-section, Indicates compensation energy, superscript No actual physical meaning.

7. The method for determining scanning melting energy in additive manufacturing according to claim 6, wherein: The compensation energy is determined by the heat dissipation of the undersized square cross section.

8. The method for determining scanning melting energy in additive manufacturing according to claim 7, wherein: The calculation formula of the compensation energy is as follows: （7） Where, represents the horizontal direction of the undersized square section on the two-dimensional plane, represents the vertical direction of the undersized square section on the two-dimensional plane, Indicates that the square is undersized. The direction component, Indicates that the square is undersized. The direction component, Indicates that the square is undersized. The heat dissipation of the layer thickness in the direction, Indicates that the square is undersized. The amount of heat dissipated by the layer thickness in the direction.

9. The method for determining scanning melting energy in additive manufacturing according to claim 8, wherein: The undersized section of the square is The calculation formula for the heat dissipation of the layer thickness in the direction is as follows: （8） The undersized section of the square is The calculation formula for the heat dissipation of the layer thickness in the direction is as follows: （9） Where, Indicates the thermal conductivity of the printing material, Indicates layer thickness, represents the melt pool temperature, Indicates that the square is undersized. The heat dissipation of the layer thickness in the direction, Indicates that the square is undersized. The amount of heat dissipated by the layer thickness in the direction.

Images