CN111941826B

CN111941826B - Block additive manufacturing method of complex part

Info

Publication number: CN111941826B
Application number: CN201910397613.6A
Authority: CN
Inventors: 孙丽娟; 黄洁; 李�昊; 邓景煜; 孙小峰; 陈洁
Original assignee: Commercial Aircraft Corp of China Ltd; Shanghai Aircraft Manufacturing Co Ltd
Current assignee: Commercial Aircraft Corp of China Ltd; Shanghai Aircraft Manufacturing Co Ltd
Priority date: 2019-05-14
Filing date: 2019-05-14
Publication date: 2022-08-12
Anticipated expiration: 2039-05-14
Also published as: CN111941826A

Abstract

The invention discloses a block additive manufacturing method of a complex part, which comprises the following steps: s1: establishing a model of the part, and analyzing a working face of the part; s2: setting the printing and placing state of the part by taking the working face as a reference element; s3: judging whether the working face N can be directly printed or not according to the printing and placing state of the parts, if so, directly printing the working face, and printing and forming the parts according to the printing and placing state in the step S2; if the working face needs to be supported to finish printing, the model of the part is divided into a plurality of sub-blocks 11; s4: setting the printing and placing states of the sub-blocks 11 by taking the sub-working surfaces of the sub-blocks 11 as reference elements; s5: the printing and molding of the sub-blocks 11 are performed according to the printing and placing state in the step S4, and the plurality of sub-blocks 11 printed and molded are spliced to complete the manufacture of the part.

Description

Block additive manufacturing method of complex part

Technical Field

The invention relates to the field of additive manufacturing, in particular to a block additive manufacturing method for a complex part.

Background

The additive manufacturing technology is different from the traditional material reduction manufacturing technology, can realize the rapid manufacturing of a plurality of complex parts, and greatly improves the material utilization rate. Meanwhile, the additive manufacturing technology has the outstanding advantages of designability, automation, rapidness and the like, the visibility and the intuition of the model are improved, the additive manufacturing technology can be directly used for functional testing, and the production efficiency and the manufacturing flexibility are greatly improved. Therefore, the additive manufacturing technology is rapidly developed and widely applied to various industries.

When the part is manufactured in an additive mode, the solid model needs to be redesigned, supporting design is carried out through related software, and printing of the part is finally achieved. However, in the actual part printing process, the support needs to be carefully designed, since the parts are often complex. The stronger support enables successful manufacture of the part, but the support is printed as part of the part together with the part, and the support structure needs to be peeled off from the part after printing is completed, so that the surface of the part may be damaged to some extent. And easily removable supports often cause part printing failures due to stress and deformation. It must be pointed out that the design of the support is closely related to the posture of the parts. In addition, most of the actually printed parts have a certain inclination angle theta in the vertical direction, and the inclination angle theta has an important influence on the forming quality of the parts.

Therefore, the dimensional accuracy and the surface quality of the working surface (such as an assembly matching surface and a positioning surface) of the printed part caused by the addition of the support or the inclination angle can not meet the use requirements, if the printed part is machined, a machining reference surface is lacked for some complex parts, and extra positioning and clamping tools are sometimes needed, so that the manufacturing cost is increased, the manufacturing period is prolonged, and the application and the popularization of the 3D printing technology are seriously limited.

Disclosure of Invention

The invention aims to provide a block additive manufacturing method of a complex part, which can ensure the dimensional precision and the surface quality of a working surface of the complex part.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method of block additive manufacturing of a complex part, the method comprising the steps of:

s1: establishing a model of a part and analyzing a working face of the part;

s2: setting the printing and placing state of the part by taking the working face as a reference element, and judging whether the working face can be directly printed or not according to the printing and placing state of the part;

s3: in step S2, if the working surface can be printed directly, the printing and forming of the parts are performed according to the printing and placing status in step S2;

s4: in step S2, if the working surface needs to be supported to complete printing, the model of the part is divided into a plurality of sub-blocks, and the printing and placing states of the sub-blocks are set with the sub-working surfaces of the sub-blocks as reference elements;

s5: and printing and molding a plurality of the sub-blocks according to the printing and placing states in the step S4, and splicing the printed and molded sub-blocks to finish the manufacturing of the part.

Optionally, in step S2, when the working surface is multiple, and multiple working surfaces are parallel to the printing platform at the same time or multiple working surfaces are perpendicular to the printing platform at the same time, the working surface may be directly printed and formed.

Optionally, in the printing process of the working surface, an included angle between a connection line of outermost points of contour lines of two adjacent forming layers and the printing platform is a printing inclination angle of the working surface, and in step S2, when the printing inclination angle of the working surface is greater than 90 °, the working surface can be directly printed and formed.

Optionally, in step S2, when the printing inclination angle of the working surface is smaller than 90 °, and the printing inclination angle of the working surface is larger than a preset angle, the working surface may be directly printed and formed; wherein: the preset angle is a support critical angle which is jointly determined by a printing material and the additive forming equipment; or the preset angle is determined by the precision requirement of the part.

Optionally, in step S4, the part is divided using a plane approximately perpendicular to the printing platform.

Optionally, in step S4, the dividing position of the part is selected as a planar extension area of the part.

Optionally, in step S4, the part division result is to ensure that the printing tilt angle of the sub-working surfaces of the sub-blocks is 0 ° or 90 °.

Optionally, in step S5, two adjacent sub-blocks are connected by a splicing assembly, where the splicing assembly includes a positioning post integrally formed on one of the sub-blocks and a positioning hole integrally formed on the other sub-block.

Further, the splicing assembly further comprises through holes formed in the two adjacent sub blocks respectively, and locking pieces penetrating through the through holes.

The block additive manufacturing method of the complex part has the following advantages:

(1) the printing and placing state of the part is determined by taking the working face of the part as a reference element, and whether the part needs to be printed in blocks is determined according to the printing and placing state, so that the dimensional accuracy and the surface quality of the working face of the complex part are better ensured.

(2) The printing and placing states of the subblocks are set by taking the sub working faces of the subblocks as reference elements, so that the forming precision of each subblock is ensured, and the forming precision of the whole part is better ensured.

(3) The plurality of sub-blocks are spliced into the complete part in a splicing mode, so that the difficulty of additive manufacturing is reduced, and the processing efficiency of the part is improved.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

FIG. 1 is a flow chart of particular steps of a method of block additive manufacturing of a miscellaneous part of one particular embodiment of the present invention;

FIG. 2 is a schematic view of a part model formed using a method of block additive manufacturing of a complex part according to an embodiment of the invention;

FIG. 3 is a schematic illustration of the part piece result shown in FIG. 2;

FIG. 4 is a schematic diagram of the splicing of two adjacent tiles shown in FIG. 2;

fig. 5 is a schematic view of a sub-block of a part formed by a method for the block-wise additive manufacturing of a hybrid part according to an embodiment of the invention.

FIG. 6 is a molding diagram of an additive manufacturing method;

fig. 7 is a schematic error diagram of an actual profile and a theoretical profile of an additive manufacturing method.

Reference numerals:

1-parts; 11-subblock; n-working face; n1-primary work surface; n2-secondary work surface; theta-printing tilt angle; m-cutting the surface; 21-positioning blocks; 22-positioning holes; 23-perforating; 24-locking member.

Detailed Description

In order to make the technical problems solved, the technical solutions adopted and the technical effects achieved by the present invention clearer, the technical solutions of the present invention are further described below by way of specific embodiments with reference to the accompanying drawings.

Specific steps of a method for the block additive manufacturing of a complex part according to an embodiment of the present invention are described below with reference to fig. 1 to 4.

As shown in fig. 1, according to the block additive manufacturing method of the complex part of the present invention, the block additive manufacturing method includes the following steps:

s1: establishing a model of the part 1, and analyzing a working surface N of the part 1;

s2: setting the printing and placing state of the part 1 by taking the working face N as a reference element, and judging whether the working face N can be directly printed or not according to the printing and placing state of the part 1;

s3: in step S2, if the working surface N can be directly printed, the printing and molding of the part 1 are performed according to the printing and placing status in step S2;

s4: in step S2, if the working plane N needs to be supported to complete printing, the model of the part 1 is divided into a plurality of sub-blocks 11, and the printing and placing states of the sub-blocks 11 are respectively set with the sub-working planes of the sub-blocks 11 as reference elements;

s5: the printing and molding of the sub-blocks 11 are performed according to the printing and placing state in step S4, and the plurality of sub-blocks 11 printed and molded are spliced to complete the manufacture of the part 1.

It will be understood that, firstly, depending on the operating conditions and the requirements of use of the part 1, it is possible to specify the respective type of plane of the part 1. Specifically, each surface of the part 1 may be divided into a working surface N (e.g., an assembly mating surface, a locating surface) and a non-working surface. In the analysis process, the acting force born by the two surfaces in the actual use process can be evaluated, the characteristics of the working surface N and the relative relationship between the surfaces can be analyzed, for example, the area size, the curvature change, the distance and the angle between discontinuous working surfaces N and the like of the working surface N can be analyzed. After the above analysis is completed, the printing and placing states of the parts 1 are set by using the parameters of the working plane N as reference elements.

Then, whether the working surface N of the part 1 can be directly printed or not is judged according to the printing and placing state of the part 1. Particularly, when working face N can directly print, working face N's shaping precision is higher, and if working face N need support just can accomplish the printing, according to the principle of vibration material disk, need add the surface that the support just can print, need get rid of the support after printing finishes, just so reduced the shaping precision and the intensity on this surface to a certain extent. Therefore, the printing and placing state of the part 1 is selected to be suitable, so that the working face N of the part 1 can be directly printed, and the printing precision of the part 1 can be guaranteed to the maximum extent.

In the invention, whether the working face N of the part 1 can be directly printed or not is judged according to the placing state of the part 1, if the working face N can be directly printed, the part 1 is directly molded, if the working face N needs to be supported to complete printing, the part 1 is divided into a plurality of subblocks 11, the printing placing state of the subblocks 11 is set according to the sub-working face contained in each subblock 11, each subblock 11 is printed according to the printing placing state of the subblock 11, and finally, each subblock 11 is spliced to form the complete part 1. Therefore, the printing and placing state is determined according to the working face N, and whether the printing is needed to be performed in blocks is determined according to the printing and placing state, so that the printing efficiency of the part 1 is guaranteed, and the forming precision of the part 1 is also guaranteed.

It should be noted that, in the embodiment of the present invention, there may be multiple working surfaces N in the component 1, and the working surfaces N may be divided into a primary working surface N1 and a secondary working surface N2 according to the stress and function of the component 1, and when the placement state of the component 1 cannot satisfy that both the primary working surface N1 and the secondary working surface N2 can directly print, the primary working surface N1 is used as a primary reference factor. That is, in the printing setting state, it is necessary to ensure that the main working surface N1 can directly print as much as possible, and if the main working surface N1 can directly print, the part 1 can be directly printed. If only the secondary work surface N2 is directly printable, part 1 needs to be printed in blocks. Of course, depending on the printing accuracy of part 1, part 1 can only be printed directly under certain conditions, provided that primary working surface N1 and secondary working surface N2 can be printed directly at the same time.

It should be added that if the printed material has the characteristic of anisotropy, the printing and placing state of the part 1, which is beneficial to increasing the bearing capacity of the part 1, needs to be preferentially selected according to the printing process, so as to meet the actual use requirement.

According to the block additive manufacturing method of the complex part, whether the complex part is blocked or not is determined through the working surface N, the respective printing and placing states of different sections are achieved through the block dividing mode, the complex part 1 is formed by splicing after printing, subsequent machining is not needed, and the forming process is simple. Meanwhile, the part 1 can be replaced and repaired conveniently in a detachable splicing mode.

Optionally, in step S2, when there are multiple working planes N, and multiple working planes N are parallel to the printing platform at the same time or multiple working planes N are perpendicular to the printing platform at the same time, the part 1 may be directly printed and formed. It can be understood that, as shown in fig. 6 to 7, according to the principle of additive manufacturing, e ═ t/tan θ (where the deviation caused by the step effect is e, t is the slice thickness, and θ is the printing inclination angle) when the working plane N is perpendicular to the printing platform, θ is 90 °, and when the working plane N is parallel to the printing platform, θ is 0 ° (non-suspended state) or 180 °. The step effect caused deviation epsilon is 0 in both cases. In this case, the part 1 can be directly printed.

Optionally, the printing inclination angle θ is an included angle between a connection line of outermost points of contour lines of two adjacent molding layers and the printing platform in the printing process of the working surface N. In step S2, when the printing inclination angle θ of the working plane N is greater than 90 °, the part 1 can be directly printed and molded. It can be understood that when the printing inclination angle θ of the working surface N is larger than 90 °, it can be determined that the working surface N does not have the cantilever structure, that is, the working surface N can directly print without being supported. In this case, the forming accuracy of the working face N is high. Therefore, the printing of the part 1 can be directly performed at this time.

Alternatively, in step S2, when the printing inclination angle θ of the working plane N is smaller than 90 °, and the printing inclination angle θ of the working plane N is larger than the support critical angle, which is determined by the printing material and the additive forming apparatus together, the part 1 can be directly printed and formed. It will be appreciated that when the printing inclination angle theta of the working surface N is less than 90 deg., the working surface N has a cantilever structure, but since the printing inclination angle theta of the working surface N is still greater than the critical angle for support, that is, the working surface N does not need to be supported, in this case, the forming accuracy of the working surface N is high. Therefore, the printing of the part 1 can be directly performed at this time.

Alternatively, when the printing inclination angle θ of the working surface N is larger than a preset angle, the part 1 can be directly printed and formed, wherein the preset angle is determined by the precision requirement of the part 1. It is understood that in some cases where the forming accuracy is more required, the printing inclination angle θ is larger than the support critical angle, but the printing accuracy is still reduced by the presence of the printing inclination angle θ according to the foregoing. Specifically, the minimum printed layer height for a typical molten fiber wire (FFF) additive manufacturing technique is 0.1mm, with a critical angle of support of 45 °. The machining accuracy of a certain part 1 is required to be controlled within 0.05 mm. In a certain printing and placing state, the printing inclination angle theta of the working surface N of the part 1 is 60 degrees, and the maximum deviation epsilon between the model and the theoretical model can be calculated to be 0.058mm according to the formula. At this time, although the printing inclination angle θ of the working face N of the part 1 is larger than the support critical angle, since the part cannot be directly printed due to its processing accuracy, block printing is required. However, when the component 1 is placed in another printing state, the printing inclination angle θ of the working surface N is 65 °, and the maximum deviation ∈ between the model and the theoretical model is 0.046 mm. At this time, the printing inclination angle theta of the working surface N of the part 1 is larger than the support critical angle, and the printing precision meets the part precision requirement. As described above, in some specific cases, the printing inclination angle θ is larger than a critical value determined according to the printing accuracy, and the forming accuracy of the component 1 can be improved more.

It should be noted here that when some complex parts 1 are printed, the working surface N of the analyzed part 1 is divided into a primary working surface N1 and a secondary working surface N2, and after multiple placements, neither the primary working surface N1 nor the secondary working surface N2 can be printed at the same time. Under such conditions, the part 1 can be directly subjected to block printing. Or selecting a proper placing state to directly print by combining the conditions. Specifically, it is necessary to ensure that the printing inclination angle θ of the primary working surface N1 is as close to 90 ° as possible, that if there are a plurality of primary working surfaces N1, the deviation due to the step effect of all the primary working surfaces N1 is epsilon enough to meet the machining accuracy requirement of the part 1, and that the printing inclination angle θ of the secondary working surface N2 is larger than the support critical angle, that is, the secondary working surface N2 does not need to be supported during printing. That is, when the primary working surface N1 and the secondary working surface N2 of the component 1 cannot satisfy the above-mentioned conditions for direct printing at the same time, the deviation caused by the step effect of one entire primary working surface N1 can be selected to satisfy the processing accuracy requirement of the component 1, and the printing layout state in which the entire secondary working surfaces N2 do not need to be supported can be selected for direct printing.

To sum up, whether part 1 can directly print and can refer to simultaneously, the contained angle size between working face N and the print platform of part 1, whether printing inclination angle theta of working face N satisfies the requirement of printing the precision and whether the working face needs to support three conditions.

Alternatively, in step S4, the part 1 is divided using a plane perpendicular to the printing platform. Therefore, the accurate surface profile of the printed and molded dividing surface M is ensured, the assembling deviation is reduced, and the molding precision of the part 1 is improved. It should be noted that, in some complex parts, when the dividing plane M may not be or is not easily perpendicular to the printing platform, a plane approximately perpendicular to the printing platform may be selected as the dividing plane M. That is, the extending direction of the dividing plane M may be selected according to the actual structure of the part 1, and it is not necessary to make the dividing plane M exactly perpendicular to the printing table.

Alternatively, in step S4, the dividing position of the part 1 is selected as the planar extension area of the part 1. Therefore, the accuracy of splicing the sub blocks 11 is guaranteed, the assembling deviation is reduced, and the forming accuracy of the part 1 is improved. It should be noted that the planar extension area may be an area where the surface of the part 1 is a plane, and if the shape of the part 1 is complex and the surface is a curved surface, the dividing position of the part 1 may be a position where the surface of the part 1 is relatively flat.

Alternatively, in step S4, the division result of the part 1 needs to ensure that the printing inclination angle θ of the sub-working surfaces of the plurality of sub-blocks 11 is 0 ° or 90 °. According to the foregoing, the printing inclination angle θ is 0 ° or 90 °, and the printing accuracy of the part 1 is high, thereby ensuring the printing accuracy of the sub-block 11 and improving the molding accuracy of the part 1. Of course, under the condition that the structure of the component 1 is complicated, the printing inclination angle θ of the sub-surfaces of the plurality of sub-blocks 11 cannot be guaranteed to be 0 ° or 90 ° regardless of the division, and under such a condition, the printing inclination angle θ of the sub-surfaces of the plurality of sub-blocks 11 can be guaranteed to be approximately 0 ° or 90 °. If the difference is large, the printing inclination angle theta of the sub working surfaces of the sub blocks 11 is also ensured to be larger than the support critical angle, or the deviation epsilon caused by the step effect calculated according to the printing inclination angle theta meets the processing precision requirement of the whole part 1.

Alternatively, as shown in fig. 5, in step S5, two adjacent sub-blocks 11 are connected by using a splicing assembly, where the splicing assembly includes a positioning post 21 integrally formed on one of the sub-blocks 11 and a positioning hole 22 integrally formed on the other sub-block 11. Therefore, the splicing accuracy of the two adjacent sub-blocks 11 is guaranteed, and the forming accuracy of the part 1 is improved. Of course, in order to further ensure the splicing accuracy of the sub-blocks 11, the printing inclination angles of the surfaces of the positioning holes 22 and the positioning columns 21 are all larger than the support critical angle, and no support needs to be added during printing.

Further, as shown in fig. 4, the splicing assembly further includes through holes 23 respectively formed in two adjacent sub-blocks 11, and locking members 24 inserted into the through holes 23. Therefore, the integral rigidity of the part 1 formed by splicing the sub-blocks 11 is ensured, and the mechanical property of the part 1 is ensured.

Optionally, a spacer may be added between two adjacent sub-blocks 11, so as to reduce the influence of the print shrinkage on the splicing accuracy.

Alternatively, in order to ensure the splicing accuracy, the positioning columns 21 and the positioning holes 22 on each sub-block 11 need to be directly printed without adding supports, or the printing inclination angles θ of the positioning surfaces of the positioning columns 21 and the positioning holes 22 meet the positioning accuracy requirement.

Example 1:

a method of block additive manufacturing of a complex part of one embodiment is described below.

(1) A model of the part 1 is established and the working surface N of the part 1 is analyzed. The part 1 shown in fig. 4 is formed by thickening a hyperbolic curved surface, and a plurality of normal holes are distributed on the curved surface. All the normal holes are respectively a main working surface N1 for positioning and needing to ensure higher precision and surface quality, the curved surface concave surface is a secondary working surface N2 for keeping relatively accurate surface contour, and the rest surfaces are non-main working surfaces. In the practical use process, each normal hole bears axial and radial acting force. Part 1 employs a molten fiber wire (FFF) additive manufacturing technique, depending on design requirements.

(2) The main working face N1 is used as a reference element to set the printing and placing states of the part 1, in the placing process, the normal holes and the concave face of the part 1 are required to be considered as the main working face N1 and the secondary working face N2, and the surfaces are required to be prevented from being supported as much as possible, so that the whole printing and placing trend is that the axes of the holes are perpendicular to the printing platform as much as possible, and the concave face is parallel to the printing platform and faces upwards as much as possible. In addition, the manufacturing process of the part 1 is an FFF technology, and has the characteristic of anisotropy, the interlayer bonding force is slightly weaker than that of the same-layer material, the axial line of each hole is vertical as much as possible during printing, and the axial bearing capacity of the hole is favorably improved.

(3) According to the multiple placement, due to the structural complexity of the part 1, the axes of the holes cannot be perpendicular to the printing platform at the same time, and one or more holes need to be supported in the printing process in the placement process. It is thus determined that the part 1 is to be printed in blocks.

(4) In the block division, the angle and position of the division plane M and the respective printing postures of the sub-blocks 11 are adjusted a plurality of times in accordance with the principle that the printing inclination angles θ of the respective holes are as close to 90 degrees as possible in consideration of the need for a sufficient space for the butt joint and the connection. As shown in fig. 3, the part 1 is divided into three pieces. It is noted here that for the three sub-blocks 11, the difference in height between the highest point and the lowest point of the sub-block 11 is as small as possible while ensuring that the printing inclination angle θ of the main working surface N1 is approximately perpendicular to the printing platform, thereby reducing the amount of support used and reducing warpage occurring during the printing process.

(5) A splicing assembly with two quadrangular positioning columns 21 and two bolt locking structures is adopted as a splicing structure of the two sub-blocks 11. Acute included angles formed by all positioning surfaces of the positioning columns 21 and the printing platform are larger than 60 degrees, two quadrilateral positioning columns 21 are arranged on a splicing and butt joint surface of one sub-block 11, the distance between the two positioning columns 21 is as far as possible, so that the positioning accuracy is better ensured, two quadrilateral positioning holes 22 with the same outline are arranged at corresponding positions on the other sub-block 11, and the distance between the positioning holes 22 and the single side of the positioning columns 21 is 0.02. It should be noted here that the conventional positioning manner is positioning by a circular positioning pin or positioning by a V-shaped groove or a dovetail groove, wherein the circular positioning pin is close to the horizontal direction to place and position two sections, which results in the bottom of the positioning pin needing to be supported and affects the positioning accuracy, and the groove positioning manner cannot fully ensure that the degree of freedom in each direction is effectively limited. In the embodiment, the positioning manner that the positioning column 21 having a quadrilateral shape is matched with the positioning hole 22 can limit circumferential positioning along the positioning axial direction, and the axial degree of freedom of the positioning hole 22 can be limited after the screw is tightened.

It should be added that when actually printing three sub-blocks 11, the FFF technique divides the sub-blocks 11 into three parts when printing the sub-blocks 11: upper and lower surface layers, walls, filling areas, each of which corresponds to one or several parameters. The rigidity of the printed sub-block 11 can be increased by increasing the thickness and the filling rate of the upper surface layer and the lower surface layer; the increase of the wall thickness can realize the increase of the rigidity of each normal hole, the positioning block at the joint and the mounting area of the locking part 24, and the effect of increasing the local filling rate is achieved. The printing material that can choose for use when printing this subblock 11 is nylon + carbon fiber chopped strand, and this kind of material printing shrinkage reduces, therefore can not carry out shrinkage compensation when printing.

In the description herein, references to the description of "some embodiments," "other embodiments," 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 invention. In this specification, the schematic representations of the terms used above do not necessarily 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.

The above description is only a preferred embodiment of the present invention, and for those skilled in the art, the present invention should not be limited by the description of the present invention, which should be interpreted as a limitation.

Claims

1. A block additive manufacturing method of a complex part is characterized by comprising the following steps:

s1: establishing a model of a part and analyzing a working face of the part;

2. The method for manufacturing the complex part by the block additive according to claim 1, wherein in step S2, the number of the working surfaces is multiple, the multiple working surfaces are parallel to a printing platform at the same time or the multiple working surfaces are perpendicular to the printing platform, and the working surfaces can be directly printed and formed.

3. The method for manufacturing the complex part by the block additive according to claim 1, wherein an included angle between a connecting line of outermost points of contour lines of two adjacent molding layers and a printing platform in the printing process of the working surface is a printing inclination angle of the working surface, and in step S2, when the printing inclination angle of the working surface is greater than 90 °, the working surface can be directly printed and molded.

4. The method for manufacturing the complex part by the block additive according to claim 3, wherein in step S2, when the printing inclination angle of the working surface is less than 90 ° and the printing inclination angle of the working surface is greater than a preset angle, the working surface can be directly printed and formed; wherein: the preset angle is a support critical angle which is determined by the printing material and the additive forming equipment together; or the preset angle is determined by the precision requirement of the part.

5. The method for block additive manufacturing of a complex part according to claim 1, wherein in step S4, the part is divided using a plane perpendicular to the printing platform.

6. The method for block additive manufacturing of a complex part according to claim 1, wherein in step S4, the dividing position of the part is selected as a planar extension of the part.

7. The method for manufacturing the complex part by the block additive manufacturing method according to claim 1, wherein in step S4, the division result of the part is to ensure that the printing inclination angle of the sub-working surfaces of the plurality of sub-blocks is 0 ° or 90 °.

8. The method for manufacturing a complex part by using a block additive manufacturing method according to claim 1, wherein in step S5, two adjacent sub-blocks are connected by using a splicing assembly, wherein the splicing assembly comprises a positioning column integrally formed on one of the sub-blocks and a positioning hole integrally formed on the other sub-block.

9. The method of additive manufacturing of a block of a complex part according to claim 8, wherein the splicing assembly further comprises through holes respectively provided on two adjacent sub-blocks, and locking members inserted into the through holes.