CN113351885A

CN113351885A - High-energy beam scanning path planning method, additive manufacturing method and device

Info

Publication number: CN113351885A
Application number: CN202110916486.3A
Authority: CN
Inventors: 李会霞; 朱纪磊; 车倩颖; 程康康; 王宇
Original assignee: Xi'an Sailong Metal Materials Co ltd
Current assignee: Xi'an Sailong Additive Technology Co ltd
Priority date: 2021-08-11
Filing date: 2021-08-11
Publication date: 2021-09-07
Anticipated expiration: 2041-08-11
Also published as: CN113351885B

Abstract

The invention relates to a high-energy beam scanning path planning method, an additive manufacturing method and a device, and relates to the technical field of additive manufacturing. The high-energy beam scanning path planning method comprises the following steps: building a three-dimensional model of the additive manufacturing part; slicing the three-dimensional model of the part layer by layer along the printing and manufacturing direction, and extracting section contour data of each layer of slice; obtaining the contour line of each layer of slices according to the section contour data of each layer of slices, and obtaining at least one continuous scanning line after the contour line is inwards contracted or outwards expanded; dividing the scanning line into N sections at random, wherein the length of each section of scanning line is less than or equal to a preset value; and numbering each section of scanning line, and scanning each section of scanning line according to a preset numbering scanning sequence, wherein at least one section of scanning line is arranged between two sections of scanning lines which are scanned successively. The invention improves the uniformity of heat distribution during the additive manufacturing of the thin-wall part, reduces the thermal stress and prevents the deformation and the cracking of the part.

Description

High-energy beam scanning path planning method, additive manufacturing method and device

Technical Field

The invention relates to the technical field of additive manufacturing, in particular to a high-energy beam scanning path planning method, an additive manufacturing method and an additive manufacturing device.

Background

High melting point metal materials, such as tungsten and tungsten alloys, molybdenum and molybdenum alloys, nickel-based high temperature alloys, and the like, have the characteristics of high melting point and boiling point, high hardness, low expansion coefficient, low vapor pressure and the like, and have important application in the fields of aerospace, electronics, chemical industry, nuclear industry and other extreme environments. However, high melting point metal materials such as tungsten and molybdenum have high melting points and low temperature brittleness, which makes it difficult to prepare them by conventional casting and machining methods. Generally, most parts made of refractory materials such as tungsten, molybdenum and the like are prepared by a powder metallurgy method, but the conventional sintered products have the defects of low density, low strength, poor plasticity, difficult control of impurity content and the like, so that parts with complex shapes, particularly thin-wall parts, are difficult to produce, and the thin-wall parts have the advantages of light weight, material saving, compact structure and the like.

In the related art, the additive manufacturing technology provides a brand-new way for integrally forming a part product with brittleness, infusibility and a complex shape. However, in the additive manufacturing direct forming process of complex metal parts, the heat source moves rapidly, the powder temperature changes rapidly along with time and space, so that thermal stress is formed, and in addition, due to the fact that the high-energy beam heating, melting, solidifying and cooling speeds are high, certain solidification shrinkage stress and structural stress exist at the same time, and under the combined action of the stress, the formed parts are easy to deform and even crack.

The existing means for controlling deformation cracking in additive manufacturing include preheating of a forming substrate, preheating of a powder bed and the like to reduce the longitudinal temperature gradient of molten metal and the forming substrate and the transverse temperature gradient in a forming surface in the forming process, however, the temperature of a molten pool under the instantaneous action of a high-energy beam is very high, although the substrate and the powder bed are preheated, the influence of the existing temperature gradient on some high-melting-point or brittle metal materials is still not negligible, and the uniformity of the distribution of the high-temperature field can be improved to a certain extent from the viewpoint of optimization of a scanning path to reduce the temperature gradient. At present, the most common melting scanning path is linear zigzag scanning, the scanning mode can better form a compact part, but the temperature field distribution in the forming process is very uneven, so that a large temperature gradient is caused, and the high-melting-point brittle material is easy to deform and crack under the action of thermal stress generated by the large temperature gradient. There is also a path planning method of point scanning, but the method is usually only used for edge pointing of a part, which limits the profile precision or loose layer of a formed part, and in the point scanning mode, a high energy beam is used for single scanning and then quickly deflected to the next position for dotting, which is very easy to splash the powder spread at the preset position, and easily causes phenomena such as 'powder blowing', and the like, which causes the forming quality to be poor and even the forming process to be stopped.

Accordingly, there is a need to ameliorate one or more of the problems with the related art solutions described above.

It is noted that this section is intended to provide a background or context to the embodiments of the disclosure that are recited in the claims. The description herein is not admitted to be prior art by inclusion in this section.

Disclosure of Invention

An object of the present invention is to provide a high-energy beam scanning path planning method, an additive manufacturing method, and an additive manufacturing apparatus, which overcome, at least to some extent, one or more of the problems due to the limitations and disadvantages of the related art.

The invention provides a high-energy beam scanning path planning method in a first aspect, which comprises the following steps:

building a three-dimensional model of the additive manufacturing part;

slicing the three-dimensional model of the part layer by layer along the printing and manufacturing direction, and extracting section contour data of each layer of slice;

obtaining the contour line of each layer of slices according to the section contour data of each layer of slices, and obtaining at least one continuous scanning line after the contour line is shrunk inwards or expanded outwards;

dividing the scanning line into N sections at random, wherein the length of each section of the scanning line is less than or equal to a preset value;

and numbering each section of the scanning line segment, and scanning each section of the scanning line segment according to a preset numbering scanning sequence, wherein at least one section of the scanning line segment is arranged between two sections of the scanning line segments which are scanned successively.

Preferably, the process of scanning each segment of the scan line segment includes:

and the high-energy beam is fed at the starting point of each section of the scanning line segment, continuously advances to the end point of the section of the scanning line segment, and then jumps to the starting point of the next section of the scanning line segment for scanning.

Preferably, the distance between adjacent positions of two adjacent continuous scanning lines and the distance between starting points of two adjacent scanning lines are set according to the size of a molten pool generated by the high-energy beam when scanning the scanning lines.

Preferably, the distance between adjacent positions of two adjacent continuous scanning lines is 0.005-0.15 mm, and the distance between the starting points of two adjacent scanning line segments is 0.005-0.15 mm.

Preferably, the step of randomly dividing the scan line into N segments, where the length of each segment of the scan line is less than or equal to a preset value includes:

and setting the preset value according to the temperature gradient of the scanning line segment during the high-energy beam scanning.

Preferably, the preset value of the length of the scanning line segment is 0.1-4 mm.

Preferably, the size of the molten pool and the temperature gradient of the scanning line section are calculated according to the material parameters of the part, the beam spot of the high-energy beam, the power of the high-energy beam, the propelling speed of the high-energy beam, the thickness of the powder layer and the temperature field of the powder bed.

Preferably, the step of numbering each segment of the scan line segment and scanning each segment of the scan line segment according to a preset numbering scanning order includes:

and predicting the distribution of the temperature gradient on each section of the scanning line segment, judging the distribution of the temperature gradient on a continuous scanning line in the section of the part, and setting the number scanning sequence of each section of the scanning line segment according to the distribution.

A second aspect of the invention provides an additive manufacturing method comprising the steps of:

planning a scanning path by using the high-energy beam scanning path planning method;

acquiring the scanning path planning data and importing the scanning path planning data into an additive manufacturing device;

and the powder spreading mechanism of the additive manufacturing device spreads metal powder on a forming substrate, and the high-energy beam melts and forms the metal powder layer by layer according to the scanning path planning data until the whole part is melted and formed.

A third aspect of the invention provides an additive manufacturing apparatus comprising a high-energy beam for additive manufacturing of a part to be processed by using the high-energy beam scanning path planning method according to any one of the above aspects.

The invention can realize the following beneficial effects:

the high-energy beam scanning path planning method provided by the invention comprises the steps of extracting section contour data of each layer of slices after slicing to obtain contour lines of each layer of slices, shrinking the contour lines inwards or expanding the contour lines outwards to obtain at least one continuous scanning line, randomly dividing the scanning lines into N sections according to a preset length, numbering each section of scanning line, and scanning each section of scanning line according to a preset numbering scanning sequence, wherein at least one section of scanning line is arranged between two sections of scanning line which are scanned successively. When the random segmented scanning path planning method is applied to additive manufacturing, the influence of powder splashing on the forming quality can be controlled to a certain degree, and meanwhile, random segmented scanning also ensures that the heat distribution is uniform in the forming process in a single-layer scanning section and the heat distribution between layers is uniform and not easy to concentrate, so that the problems of part deformation and crack propagation caused by thermal stress are avoided, and the forming quality of parts is ensured.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure. It is to be understood that the drawings in the following description are merely exemplary of the disclosure, and that other drawings may be derived from those drawings by one of ordinary skill in the art without the exercise of inventive faculty.

1 a-1 c show schematic temperature profiles after linear scanning for additive manufacturing techniques according to the prior art;

FIG. 2 illustrates a schematic powder splash diagram under a prior art additive manufacturing technique point scan process;

FIG. 3 is a schematic flow chart illustrating a method for planning a scanning path of a high-energy beam according to an embodiment of the present invention;

4 a-4 b show schematic diagrams of three-dimensional models of thin-walled parts of two different shapes in an embodiment of the invention;

FIGS. 5 a-5 b are schematic diagrams illustrating the contours and scan lines of a layer of a three-dimensional model according to an embodiment of the present invention;

FIGS. 6 a-6 d are schematic diagrams illustrating a segment of a scan line in an embodiment of the invention;

7 a-7 b are schematic diagrams illustrating temperature distribution states of the cross section of the thin-wall part scanned by the high-energy beam scanning path planning method in the embodiment of the invention;

FIG. 8 shows a schematic flow chart of steps of an additive manufacturing method in an embodiment of the invention;

FIGS. 9 a-9 b are schematic diagrams of a three-dimensional model of a tungsten grid and a layer of a tungsten grid model illustrating contours and scan lines according to an embodiment of the present invention;

FIG. 10 shows a cross-sectional view of a formed tungsten grid in an embodiment of the invention;

FIG. 11 illustrates a diagram of a shaped tungsten grid sidewall in an embodiment of the present invention;

fig. 12 shows a schematic structural diagram of an additive manufacturing apparatus in an embodiment of the invention.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many different 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 concept of 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.

Referring to fig. 1, fig. 1 is a schematic diagram of temperature distribution after linear scanning in the conventional additive manufacturing technology, and fig. 1 (a) shows a temperature gradient distribution during a scanning melting process when a molten pool generated by a high-energy beam advances forward, where darker colors in the diagram represent higher temperatures, which means that the temperature is highest near the front end of the molten pool, a certain heat-affected zone is accumulated before and after the temperature is highest, and the temperature is gradually decreased after a melted and solidified part is far away from the molten pool. Fig. 1 (b) and (c) show two kinds of morphology cross sections drawn according to current printing simulation and practical experimental experience, and it can be seen that the temperature field distribution is not uniform in some regions of the part due to the temperature distribution after melting and forming by linear scanning, and the part is prone to deformation and cracking.

Referring to fig. 2, fig. 2 is a schematic diagram of powder splashing in a point scanning process in the additive manufacturing technology in the prior art, according to practical experiments, under the action of a high energy beam, when continuously jumping to perform point-by-point scanning, the powder at an original position is easily deviated from the original position to cause splashing under the impact of the high energy beam, the powder at the original position is reduced due to splashing, the powder is easily sunk to cause uneven powder spreading, fusion is poor to form defects, and the powder splashing to other positions is also easily caused defects. In addition, limited by hardware conditions, the melting scanning speed of the point scanning is generally slower than that of the continuous scanning, so that the forming efficiency is influenced.

Based on this, the embodiment of the present invention first provides a method for planning a scanning path of a high energy beam, which is shown in fig. 3 and includes steps S101 to S105:

step S101, building a three-dimensional model of the additive manufacturing part.

And S102, slicing the three-dimensional model of the part layer by layer along the printing and manufacturing direction, and extracting section contour data of each layer of slice.

And step S103, obtaining the contour line of each layer of slice according to the section contour data of each layer of slice, and obtaining at least one continuous scanning line after the contour line is inwards contracted or outwards expanded.

And step S104, dividing the scanning line into N sections at random, wherein the length of each section of the scanning line is less than or equal to a preset value.

And step S105, numbering each scanning line segment, and scanning each scanning line segment according to a preset numbering scanning sequence, wherein at least one scanning line segment is arranged between two scanning line segments which are scanned successively.

Next, the respective steps of the above-described method in the present exemplary embodiment will be described in more detail with reference to fig. 4 to 7.

In step S101, a three-dimensional model of a to-be-machined part needs to be constructed, specifically, the to-be-machined part may be a solid part or a thin-walled part. For example, in one embodiment, three-dimensional solid models of thin-walled parts of two different shapes are shown in fig. 4 (a) and (b), respectively. The specific process of constructing the three-dimensional model, which is not described in detail in this embodiment, can refer to the prior art.

In step S102, the three-dimensional solid model may be sliced in layers along the printing manufacturing direction, and cross-sectional profile data of each layer slice may be extracted. For example, if the printing direction is the z-axis direction in fig. 4, the slicing software performs slicing along the z-axis direction according to a preset slice thickness, and the cross section of each slice is shown as the dotted line portion of the uppermost layer of the three-dimensional model.

In step S103, contour lines of the slices of each layer are obtained from the cross-sectional contour data of the slices of each layer, and at least one continuous scanning line is obtained after the contour lines are shrunk inward or expanded outward, and the continuous scanning lines may be closed or non-closed. Referring to fig. 5, fig. 5 (a) is a schematic diagram showing the outline of a layer of the three-dimensional model of fig. 4 (a), and fig. 5 (b) is a schematic diagram showing the outline of a layer of the three-dimensional model of fig. 4 (b). Specifically, in fig. 5 (a), the contour line 100 of one slice is obtained from the cross-sectional contour data of the slice extracted in S102, and after the contour line 100 is shrunk inward twice, two continuous closed scanning lines 200 are obtained. In fig. 5 (b), the contour line 100 obtained from the cross-sectional contour data of the slice includes one inner contour line 101 and one outer contour line 102, and the outer contour line 102 is contracted inward to obtain one continuously closed scanning line 200, and the inner contour line 101 is expanded outward to obtain another continuously closed scanning line 200. It should be noted that the scan lines 200 shown in dashed lines in fig. 5 are continuous in nature and are shown in dashed lines merely for purposes of illustration to distinguish them from contour lines.

In one embodiment, the distance between adjacent positions of two adjacent continuous scanning lines can be set by the size of a molten pool generated by the high-energy beam when scanning the scanning line segment, and the specific calculation process of the size of the molten pool can be calculated by modeling in a computer by using the material parameters of the part, the beam spot of the high-energy beam, the power of the high-energy beam, the advancing speed of the high-energy beam, the thickness of the powder layer and the temperature field distribution of the powder bed. Wherein the material parameters of the part include, but are not limited to, the thermal conductivity, shrinkage solidification, and melting point temperature of the material. For example, when a pure molybdenum thin-wall part is formed, the size of a molten pool generated by a high-energy beam is calculated by computer modeling according to relevant parameters of a pure molybdenum material and forming process parameters to be about 0.2mm, and in order to ensure that two adjacent scanning lines can have enough remelting and overlapping during melting so as to realize good internal metallurgical quality and avoid heat concentration caused by overhigh remelting and overlapping rate, the distance between adjacent positions of two adjacent continuous scanning lines can be 0.08mm, 0.09mm or 0.1mm and the like. In addition, the spacing value between the adjacent positions of two adjacent continuous scanning lines is matched with the selection of other parameters to be mutually restrained.

In one embodiment, as shown in FIGS. 5 (a) and 5 (b), the distance between two adjacent consecutive scan lines 200 is Δ h. Specifically, the range of the Δ h is 0.005-0.15 mm, and in the range of the distance, enough remelting and overlapping can be ensured between two adjacent scanning lines during melting so as to realize good internal metallurgical quality and avoid heat concentration caused by overhigh remelting and overlapping rate.

In step S104, the scan line 200 is randomly divided into N segments, and the length of each segment is set to be less than or equal to a preset value.

In one embodiment, the scan line segments may be equal or unequal, and N is an integer greater than or equal to 2, but the present disclosure does not limit the specific number of N, and does not limit whether the scan line segments are consistent in length or are regularly divided. In practice, the profile shape, material properties and specific data can be defined to reduce the temperature gradient as much as possible and ensure uniform heat dispersion during scanning and melting. For example, in fig. 6, the same scan line is divided into 4 different segmentation methods. In fig. 6 (a), the scan lines are divided into 11 segments of equal length; in fig. 6 (b), the scan lines are divided into 7 segments of equal length; in fig. 6 (c), the scan line is divided into 12 segments in a long-short manner; in fig. 6 (d), the scan line is divided into 15 segments in a one-long-two-short manner.

In one embodiment, the specific length preset value of each scanning line segment can be set according to the temperature gradient of the scanning line segment under the action of the high-energy beam, and the calculation process of the specific temperature gradient can be calculated by modeling in a computer by using the material parameters of the thin-wall part, the beam spot of the high-energy beam, the power of the high-energy beam, the propelling speed of the high-energy beam, the thickness of the powder layer and the temperature field of the powder bed. The material parameters of the component include, but are not limited to, the thermal conductivity, shrinkage solidification coefficient, and melting point temperature of the material. For example, when a pure molybdenum thin-wall part is formed, computer modeling calculates that when the length of a scanning line is 4mm, the highest temperature gradient of the scanning line is greater than 800 ℃ after the scanning line is melted, and when the length of the scanning line is 2mm, the highest temperature gradient of the scanning line is only 500 ℃, the length of the scanning line with the length of 2mm is more beneficial to control of thermal stress than the length of the scanning line with the length of 4mm, and in an actual situation, the length of the scanning line needs to be combined with material characteristics, part characteristics and process conditions, and a proper length of the scanning line is selected more accurately through computer simulation and actual tests according to relevant parameters of a pure molybdenum material and forming process parameters (including beam spots of a high-energy beam, the power of the high-energy beam, the propelling speed of the high-energy beam, the thickness of a powder layer, the temperature field of a powder bed and the like).

In one embodiment, the preset length of the scan line segment is 0.1-4 mm. Under the length range, heat generated in the forming process is not easy to concentrate and is further uniformly distributed, the problem of deformation and cracking caused by thermal stress is avoided, and meanwhile, good metallurgical quality in the part can be guaranteed.

In step S105, each segment of the scan line segment is numbered, and each segment of the scan line segment is scanned according to a preset numbered scanning sequence, wherein at least one segment of the scan line segment is spaced between two segments of the scan line segment that are scanned successively. Specifically, taking fig. 6 (a) as an example, the number of the 11 scan lines is L1, L2 · · L11, and the scan order is set according to the number of each segment. For example, in one embodiment, the high energy beam may complete scan line melting in the order of L1, L3, L5, L7, L9, L11, L2, L4, L6, L8, L10. In another embodiment, the scan line melting may also be done in the order of L1, L10, L8, L6, L4, L2, L11, L9, L7, L5, L3. Of course, in other embodiments, the scan line melting may be completed in the order of L1, L4, L7, L10, L2, L5, L8, L11, L3, L6, and L9, or may be completed in the order of L1, L5, L3, L6, L2, L7, L10, L8, L4, L11, and L9. In the present disclosure, the scanning of each segment requires at least 1 scan line segment between two adjacent scan line segments scanned successively, and the scanning sequence is not limited, and the scanning sequence of each numbered scan line segment may be a sequence from small to large, certainly from large to small, or may be interspersed, and the scanning of two successive scans may be of 1 scan line segment at the interval, or of 1 scan line segment at the interval or more.

In one embodiment, step S105 further comprises the steps of: and predicting the distribution of the temperature gradient on each section of scanning line segment, and setting the number scanning sequence of each section of scanning line segment according to the distribution of the temperature gradient. The scanning sequence is set according to the distribution condition of the temperature gradient, so that the heat distribution of each layer of section of the thin-wall part is more uniform during melting and forming, the temperature gradient is smaller, and the finally formed thin-wall part is not easy to deform. For example, in a continuous closed scan line composed of 7 scan line segments including L1, L2, L3, L4, L5, L6, and L7, if it is predicted that the temperature gradient after the L1 scan is completed is high, in order to reduce the thermal stress caused by heat accumulation without continuing to accumulate heat, it is preferable to scan an L4 or L5 scan line segment with a longer distance and a minimum heat accumulation effect under the condition that at least one scan line segment is spaced between two adjacent scan line segments that are scanned successively.

Specifically, the distribution of the temperature gradient can be predicted through the material parameters of the thin-wall part, the beam spot of the high-energy beam, the power of the high-energy beam, the propelling speed of the high-energy beam, the thickness of the powder layer and the temperature field of the powder bed. The material parameters of the thin-walled part include, but are not limited to, the thermal conductivity coefficient, the shrinkage solidification coefficient, and the melting point temperature of the material.

In one embodiment, in forming any layer of part cross section, the selection of the starting scan line segment number in the N scan lines is also random, for example, the starting scan line segment number of the cross section of the first layer may be 1, the starting scan line segment number of the cross section of the second layer may be 2, and the starting scan line segment number of the cross section of the third layer may be 3. Therefore, the disorder of interlayer scanning is increased as much as possible, the uniformity of heat distribution in the forming process is improved, and the deformation and cracking of parts caused by thermal stress are avoided.

In one embodiment, the segments and the segment scanning order of the adjacent two layers of scanning lines are different, for example, the n-1 th layer of scanning line segment pattern is equally divided by short line segments, the n-1 th layer of scanning line segment pattern can be two short and one long, and the n +1 th layer of scanning line segment pattern can be equally divided by long line segments. The N-1 th layer scan line may be divided into N segments, the N-th layer scan line may be divided into 1.5 xn, and the N +1 th layer scan line may be divided into 1.2 xn segments. The scanning line scanning sequence of the n-1 th layer can be numbered from small to large, the scanning line scanning sequence of the n-1 th layer can be numbered from large to small, and the scanning line scanning sequence of the n +1 th layer can be size-alternated. Therefore, the scanning disorder is increased as much as possible, the uniformity of heat distribution in the forming process is improved, and the deformation and cracking of parts caused by thermal stress are avoided.

In one embodiment, the scan line segment of each segment is completed by the continuous scan of the high-energy beam after being fed back and pushed forward, and then the melting scan is started by jumping to the starting end of the next scan line segment. The scanning mode can avoid the problem that the powder splashes, causes uneven powder spreading and poor fusion and forms defects on the one hand, and also ensures that heat can be uniformly distributed as far as possible in the forming process on the other hand, thereby avoiding the problem of deformation and cracking of parts caused by thermal stress.

In one embodiment, referring to FIG. 6 (a), the distance between the starting points of adjacent scan lines is 0.005-0.15 mm. Because the end and the starting end of the adjacent scanning line segments have a certain area under the action of the high-energy beam, a proper distance L between the positioning centers of the end and the starting end of the adjacent two scanning lines during the high-energy beam scanning is kept to ensure a proper lap joint rate, the fusion quality of a lap joint area is ensured, and the heat concentration of one part caused by the multiple times of scanning of the high-energy beam spot can be avoided. And when the distance between the scanning line sections is kept at 0.005-0.15 mm, the fusion of all sections of the thin-wall part is complete and the thin-wall part is not deformed and cracked just after the high-energy beam scanning.

Fig. 7 (a) and 7 (b) are schematic temperature distribution diagrams of the cross section of the thin-wall part scanned and melted by the high-energy beam scanning path planning method, and it can be seen that the method of the present disclosure has more uniform heat distribution, smaller temperature gradient and less deformation.

An embodiment of the present invention further provides an additive manufacturing method, which is shown in fig. 8 and includes the following steps:

step S201, planning a scanning path by using the high-energy beam scanning path planning method according to any of the embodiments.

Step S202, obtaining the scan path planning data and importing the scan path planning data into an additive manufacturing device. Inputting forming technological parameters, and filling metal material powder. Specifically, the metal material powder may be molybdenum powder, molybdenum alloy powder, tungsten alloy powder, nickel-based superalloy powder, or an element mixture powder, and the like, but is not limited thereto.

Step S203, spreading metal powder on a forming substrate by a powder spreading mechanism of the additive manufacturing device, selectively melting the metal powder by a high-energy beam according to the scanning path planning data to form a single-layer melting sheet layer, descending the forming substrate to a specific height, and repeating powder spreading and selective area melting until the whole part is melted and formed. Specifically, the energy source of the high-energy beam may be a laser, an electron beam, an arc, or the like, but is not limited thereto.

In a specific embodiment, a tungsten grid model is created using three-dimensional modeling software, see fig. 9 (a), with dimensions of 0.1mm wall thickness and 1.05mm aperture. And performing layer cutting processing on the model by using layer cutting software to obtain two-dimensional section data of the three-dimensional model, wherein the thickness of the cutting layer is 0.05 mm. Referring to fig. 9 (b), the outer contour line 102 and the inner contour line 101 of each slice are obtained according to the cross-sectional profile data of each slice, the outer contour line 102 is shrunk inwards, and the inner contour line 101 is expanded outwards, so that two closed continuous scanning lines 200 are obtained. And carrying out random segmentation and scanning sequence planning on the closed continuous scanning lines. And equally dividing the closed continuous scanning line according to the length of 2mm of each segment, wherein the scanning sequence is clockwise, and at least 1 segment of scanning line segment is arranged between every two adjacent segments of scanning line segments. And (3) guiding the two-dimensional section cutting layer and path planning data of the three-dimensional model into electron beam selective melting forming equipment, inputting melting process parameters, and filling pure tungsten powder. The powder spreading mechanism spreads tungsten powder on the forming substrate, the electron beam selectively melts the tungsten powder according to two-dimensional cross-section path planning data to form a single-layer melting sheet layer, the forming substrate descends to a specific height, and the powder spreading and selective melting are repeated until the whole tungsten grid part is melted and formed. The thin-walled part formed by the test is observed, and referring to fig. 10 and 11, fig. 10 is a cross-sectional gold phase diagram of the tungsten grid, and the tungsten grid is free of cracks, holes and poor fusion defects, and fig. 11 is a side wall diagram of the tungsten grid.

In summary, the additive manufacturing method provided by the invention ensures the forming quality of the thin-wall part and avoids the problem of generating cracks in the additive manufacturing forming process.

An embodiment of the present invention further provides an additive manufacturing apparatus, and specifically, as shown in fig. 12, the additive manufacturing apparatus includes: the powder spreading mechanism 300, the forming platform 400, the lifting mechanism 500, the control unit 600 and the high energy beam 700. When the additive manufacturing device performs additive manufacturing on a thin-wall part to be processed by using the high-energy beam 700, the additive manufacturing device performs additive manufacturing by using the high-energy beam scanning path planning method according to any one of the embodiments. Wherein, the powder spreading mechanism 300, the lifting mechanism 500 and the high-energy beam 700 are respectively connected with the control unit 600. The powder spreading mechanism 300 is located above the forming platform 400, and spreads powder on the forming platform 400 under the control of the control unit 600. The high-energy beam 700 is positioned above the powder spreading mechanism 300, and scans, preheats and melts the powder on the forming platform 400. The lifting mechanism 500 is located below the forming platform 400, and the forming platform 400 is lifted under the control of the control unit 600, and the two may be fixedly connected. The high energy beam 700 may be, but is not limited to, a laser, an electron beam, a plasma beam, etc.

It is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like in the foregoing description are used for indicating or indicating the orientation or positional relationship illustrated in the drawings, and are used merely for convenience in describing embodiments of the present invention and for simplifying the description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the embodiments of the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present invention, "a plurality" means two or more unless specifically limited otherwise.

In the embodiments of the present invention, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "fixed," and the like are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrated; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present disclosure can be understood by those of ordinary skill in the art as appropriate.

In embodiments of the invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise the first and second features being in direct contact, or the first and second features being in contact, not directly, but via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. A high-energy beam scanning path planning method is characterized by comprising the following steps:

building a three-dimensional model of the additive manufacturing part;

2. The method for planning the scanning path of the high energy beam according to claim 1, wherein the scanning of each segment of the scanning line segment comprises:

3. The method for planning the scanning path of the high energy beam according to claim 1, wherein the distance between adjacent positions between two adjacent continuous scanning lines and the distance between the starting points of two adjacent scanning lines are set according to the size of a molten pool generated by the high energy beam when scanning the scanning lines.

4. The method for planning the scanning path of the high energy beam according to claim 3, wherein the distance between the adjacent positions of the two adjacent continuous scanning lines is 0.005-0.15 mm, and the distance between the starting points of the two adjacent scanning lines is 0.005-0.15 mm.

5. The method for planning the scanning path of the high energy beam according to claim 1, wherein the step of randomly dividing the continuous scanning line into N segments, and the length of each segment of the scanning line is less than or equal to a preset value comprises the following steps:

6. The method for planning the scanning path of the high energy beam according to claim 5, wherein the preset value of the length of the scanning line segment is 0.1-4 mm.

7. The method for planning the scanning path of the high-energy beam according to claim 3 or 5, wherein the size of the molten pool and the temperature gradient of the scanning line segment are calculated by the material parameters of the part, the beam spot of the high-energy beam, the power of the high-energy beam, the advancing speed of the high-energy beam, the thickness of the powder layer and the temperature field of the powder bed.

8. The method for planning the scanning path of the high energy beam according to claim 1, wherein the step of numbering each segment of the scanning line and scanning each segment of the scanning line according to a preset numbering scanning sequence comprises:

9. An additive manufacturing method, comprising the steps of:

planning a scanning path by using the high-energy beam scanning path planning method according to any one of claims 1 to 8;

10. An additive manufacturing device, characterized by comprising a high-energy beam, wherein the high-energy beam is used for additive manufacturing of a part to be processed by the high-energy beam scanning path planning method according to any one of claims 1 to 8.