Integrated 3D printing method and system for kinematic mechanisms

Abstract

The application discloses a kind of integrated 3D printing methods and systems for kinematic mechanism, the method includes two parts of software generation and actual production, software generation is used to analyze the model containing kinematic mechanism to determine the position needing auxiliary printing, and add bridge support structure or adopt arch printing structure in the position needing auxiliary printing, generate G code file that can be directly used for printing;Actual production includes 3D printing according to G code file, obtains preliminary model, removes bridge support structure and obtains the printed part containing kinematic mechanism.This method replaces traditional support structure by bridge support structure, easy to remove and will not affect the mechanism movement;By arch printing method, avoid long distance hanging structure droop, avoid structure mutual adhesion in printing process.This method not only can simplify manufacturing process, reduce manual assembly, support removal and overall printing time, but also can produce complex motion structure with different deformation mode and steady control.

Description

Technical Field

[0001] This invention belongs to the field of 3D printing technology and relates to an integrated 3D printing method and system for kinematic mechanisms. Background Technology

[0002] 3D printing, as a rapid prototyping technology, can typically create objects or solid models that are difficult to physically modify. However, existing 3D printing strategies struggle to manufacture multi-part moving mechanisms. On one hand, traditional multi-step manufacturing processes require interconnected assembly steps, which are time-consuming, labor-intensive, and prone to errors due to printing mistakes. On the other hand, in existing monolithic printing, the printed supports fill all internal gaps, hindering mechanical movement. Therefore, it is necessary to provide a more optimized monolithic 3D printing method for kinematic mechanisms. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by proposing an integrated 3D printing method and system for kinematic mechanisms. This method, through a specially controlled arched printing structure and bridging support structure, allows for the production of kinematic mechanisms using a one-step desktop FDM 3D printer, eliminating the need for additional post-processing and assembly. The method of this invention significantly reduces printing time, material consumption, and additional labor costs.

[0004] The technical solution adopted in this invention is as follows:

[0005] An integrated 3D printing method for kinematic mechanisms includes two parts: software generation and actual production. The software generation is used to analyze the model containing the kinematic mechanism to determine the locations that require auxiliary printing, and to add bridging support structures or use arched printing structures at the locations that require auxiliary printing, generating G-code files that can be directly used for printing. The actual production includes 3D printing according to the G-code file to obtain a preliminary model. The preliminary model contains bridging support structures or structures implemented using arched printing. The bridging support structures are then broken to obtain the printed part containing the kinematic mechanism, completing the finished product production.

[0006] In the above technical solution, the software generation further includes:

[0007] Input Model: The user inputs any virtual entity model as a base; kinematic mechanism parts are set on the virtual entity model according to the required deformation position and motion requirements;

[0008] Model settings: The obtained model is simplified into a quadrilateral mesh. Then, the user adjusts the motion mode and range of motion of the kinematic mechanism, and controls the gap range between the parts in the kinematic mechanism. Due to the limited precision of the printer, the gap width can usually be set to 0.2-0.4mm to avoid adhesion during the printing process. The completed model is then previewed.

[0009] Model Analysis: Analyze the obtained model. For parts that are attached to the 3D printing platform during actual printing, use conventional 3D printing methods directly. For parts that are not attached to the 3D printing platform during actual printing, determine the positions that require auxiliary printing and the methods of auxiliary printing. The auxiliary printing methods include adding bridging support structures or using arched printing structures.

[0010] Furthermore, for parts that are not attached to the 3D printing platform during actual printing, the locations and methods of auxiliary printing are determined. Specifically, this includes: analyzing each mesh surface of the part; if the normal vector of the mesh surface is close to the vertically downward direction and the included angle is less than a first preset value, then the location of the mesh surface can be assisted by adding a bridging support structure. Typically, the first preset value can be set to 52°. If the normal vector of the bottom surface of the suspended structure part of the part is vertical, then the suspended structure part can be assisted by an arched printing structure. In particular, when the length of the suspended structure part is long, such as exceeding 5cm, an arched printing structure should be used to assist printing in order to reduce the drooping of the printing filament and avoid deformation of the suspended structure part after printing.

[0011] Furthermore, the addition of the bridging support structure specifically includes: adding a "bridge-shaped" bridging support structure at the grid surface position, and during actual printing, both ends of the bridging support structure must be placed on the printed parts to support the parts to which the grid surface belongs.

[0012] Furthermore, the addition of the bridging support structure also includes: for the component to which the grid surface belongs, sliced ​​horizontally from bottom to top, for each increase of the height by a second preset value, a "bridge-shaped" bridging support structure is added in the geometric center direction of the corresponding slice, and both ends of the bridging support structure must be placed on the printed component during actual printing. The second preset value can usually be set to 2cm.

[0013] Furthermore, the use of an arched printing structure specifically includes: slicing the suspended structure portion horizontally from bottom to top, replacing the bottom slice with an arch, and gradually decreasing the curvature of the arch in each upward slice until, for example, after 4-6 layers, the top slice is a horizontal structure.

[0014] Furthermore, the bottommost slice is replaced with an arch shape, the curve of which is:

[0015]

[0016] Where the length of the slice is taken as the x-direction, the upward direction as the z-direction, x is the x-coordinate, Z(x) is the z-height, r is the arch height, s is the span, and l p The width in the x-direction of the horizontal connecting sections on both sides of the arched structure.

[0017] Furthermore, the method for generating the G-code file includes the following: printing the virtual entity model using conventional 3D printing methods to generate the original G-code file; replacing or inserting the G-code of the added bridging support structure or the arched printing structure into the original G-code file; and weaving the G-codes of the two printing methods together to obtain a G-code file that can be directly printed.

[0018] Furthermore, the printing parameters for the bridging support structure are: PLA material, extrusion ratio per unit length of 1.2, and printing speed of 20 mm / s, to ensure the toughness and support strength of the bridging support structure.

[0019] An integrated 3D printing system for kinematic mechanisms, the system being used to implement the software generation portion described in the method above.

[0020] The beneficial effects of this invention are:

[0021] The method and system provided by this invention not only simplify the manufacturing process of moving mechanical structures, reducing printing time and cognitive costs, but also integrate multiple deformation actions, multi-steady-state control, and continuous creation reverse design methods. This allows for faster and more efficient manufacturing, while simultaneously producing complex moving structures with different deformation modes and steady-state controls. Furthermore, this method replaces traditional support structures with bridging supports, making the bridging supports easy to remove without affecting movement; and avoids sagging of long-distance suspended structures through arched printing. Through systematic experiments on printing parameters, we have demonstrated the feasibility of 3D printing arched bridging structures using the method of this invention, as well as the strength and detachability of the bridging supports. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the process for setting up the software-generated model in this invention;

[0023] Figure 2 This is a schematic diagram of the model analysis in the software-generated part of this invention;

[0024] Figure 3 This is a comparison diagram of the bridging support method (bottom) of the present invention and the traditional support method (top);

[0025] Figure 4 A schematic diagram illustrating the arched printed curve;

[0026] Figure 5 This is a comparison diagram of the arched printing method of the present invention (bottom) and the traditional support method (top);

[0027] Figure 6 Schematic diagrams of three single-degree-of-freedom deformation structures printed using the method of this invention;

[0028] Figure 7 Schematic diagrams of two multistable structures printed using the method of this invention;

[0029] Figure 8 A schematic diagram of printing a stretchable structure using the method of this invention;

[0030] Figure 9 A schematic diagram illustrating the printing of a toy hedgehog using the method of this invention; Detailed Implementation

[0031] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific examples.

[0032] The integrated 3D printing method for kinematic mechanisms of the present invention includes two parts: software generation and actual production. The software generation is used to analyze the model containing the kinematic mechanism to determine the locations that need to be assisted in printing, and to add bridging support structures or use arched printing structures at the locations that need to be assisted in printing, generating G-code files that can be directly used for printing. The actual production includes 3D printing according to the G-code file to obtain a preliminary model. The preliminary model contains bridging support structures or structures implemented using arched printing. The bridging support structures are then removed to obtain the printed part containing the kinematic mechanism, thus completing the printing process.

[0033] Specifically:

[0034] The software generation part (such as) Figure 1 (As shown) includes:

[0035] Input Model: The user inputs any virtual entity model as a base; kinematic mechanism parts are set on the virtual entity model according to the required deformation position and motion requirements;

[0036] Model Setup: The model is simplified to a quadrilateral mesh. The user then adjusts the motion mode and range of motion of the kinematic mechanism, regulates the gaps between parts within the mechanism, and previews the completed model. Figure 1 In this invention, the user inputs a virtual dinosaur model, controls the generation position of the mechanical structure by selecting the dinosaur's neck area, and completes the final printed model by selecting the stretching length and direction. The software generation section of this invention can also include a DIY design component.

[0037] For experienced users, we offer follow-up or full-process DIY design services to achieve more complex and customized motion. To ensure the designed components are printable, the DIY design must meet the following conditions:

[0038] For components not attached to the platform,

[0039] Most of the P1 assembly should be located between the housing or other components;

[0040] P2 should have more than half of its bottom parallel to the printing platform, and the angle of the remaining part should be greater than 35 degrees.

[0041] The wall thickness of P3 should not be less than 1.5 mm;

[0042] For long-span suspension structures,

[0043] P4 ensures that the bottom of the structure is parallel to the printing bed;

[0044] P5 avoids incorporating complex shapes, such as corners, into hanging objects;

[0045] P6 should not exceed 10cm in length.

[0046] Model Analysis: Analyzing the obtained model, for parts that are attached to the 3D printing platform during actual printing, conventional 3D printing methods are directly used. For parts that are not attached to the 3D printing platform during actual printing, the locations requiring auxiliary printing and the methods of auxiliary printing are determined. These auxiliary printing methods include adding bridging support structures or using arched printing structures. For example... Figure 2 As shown, the model includes two parts. The bottom part is attached to the 3D printing platform and can be printed directly using conventional 3D printing. The top part is not attached to the platform and may require auxiliary printing.

[0047] Analyzing each grid surface of the component, if a grid surface is located on the bottom surface of the component, or on the bottom surface of the suspended structure portion of the component, and its normal vector forms an angle with the vertical direction, and the angle is less than a first preset value, then the position of this grid surface can be achieved using an auxiliary printing method that adds a bridging support structure. Typically, the first preset value can be set to 52°. Figure 2 As shown in Figure b, the bottom surface of the upper component needs to be reinforced with a bridging support structure. If the normal vector of the bottom surface of the suspended structure of the component is vertical, the suspended structure can be printed using an arched printing structure, especially when the length of the suspended structure is long, such as exceeding 5cm, to reduce the sagging of the printing filament and prevent deformation of the suspended structure after printing. Figure 2 The suspended structure above the component shown in b can be printed using an arched structure.

[0048] The addition of the bridging support structure specifically includes: adding a "bridge-shaped" bridging support structure at the grid surface location, and ensuring that both ends of the bridging support structure are placed on the already printed component during actual printing to support the component belonging to the grid surface, thus providing strong support for the bottom layer. It may also include: for each horizontal slice of the component belonging to the grid surface from bottom to top, for every second preset value increase in height, adding another "bridge-shaped" bridging support structure at the geometric center of the corresponding slice, and ensuring that both ends of the bridging support structure are placed on the already printed component during actual printing to prevent the object from swaying during printing. Typically, the second preset value can be set to 2cm. Figure 2 As shown in Figure c, the added bridging support structure is illustrated.

[0049] Typically, the printing parameters for bridging support structures can be set as follows: PLA material, extrusion ratio per unit length of 1.2, and printing speed of 20mm / s to ensure the toughness and support strength of the bridging support structure. Based on our manufacturing experience, each bridging support structure can withstand a weight of approximately 6 grams. This allows us to calculate the required number of bridging support structures. After deducting the bottom layer and the bridging support structures added towards the center to prevent wobbling, the remaining bridging support structures can be added evenly to the bottom of the part to ensure it can be printed intact.

[0050] like Figure 3 As shown, the main purpose of the bridging support structure is to replace traditional supports that are difficult to remove in the gaps of the mechanism. In the traditional layer-by-layer printing strategy, suspended components not attached to the platform require bottom-up support structures (such as...). Figure 3 (As shown in b). These supports are fatal to mobility because they cannot be removed within enclosed or semi-enclosed spaces (e.g., ...). Figure 3 (As shown in b3). In the above situation, the bridging support structure of the present invention or the arched printed filaments can be used as alternatives for support. Specifically, for example, by connecting several filaments of the bridging support structure to the wall (e.g. Figure 3 As shown in c2), the first layer of the intermediate components can be printed on them.

[0051] To meet the needs of actual printing and manufacturing, and in accordance with the generation logic of G-code, the generation of the bridging support structure needs to meet the following five principles:

[0052] P1. The printing order from bottom to top, layer by layer, does not conflict with existing G-code.

[0053] P2. Both ends of the bridging support must rest on an existing vertical surface or printed material.

[0054] P3. Provide sufficient strength to support the load of the object above.

[0055] P4. Non-linear arrangement to prevent the object above from shaking during printing due to the print head, thus affecting the quality.

[0056] P5. Generate as few bridging support structures as possible so they can be easily removed after printing.

[0057] P1 allows the generated print files to be compatible with traditional printers, while P2 and P3 ensure that the generated objects can be printed correctly. P4 and P5 meet the user's requirements for high-quality manufacturing and minimize manual post-processing.

[0058] The arched printing structure is specifically described as follows: the suspended structure is sliced ​​horizontally from bottom to top, the bottom slice is replaced with an arch, and the curvature of the arch of each slice decreases layer by layer until the top slice is a horizontal structure.

[0059] The arched curve is described using a correlation function. For example... Figure 4 In the coordinate system shown, the length of the arch structure in the X direction is called the span, and the height in the Z direction is called the arch height. Through actual testing, the arctan function, due to its relatively smooth and stable curvature, can achieve good printing results. Therefore, the arch curve can be described by the following function:

[0060]

[0061] Where r is the arch height, s is the span, and l p This refers to the width of the bridge columns on both sides of the arch structure. Besides the arch function, the number of arch layers, span, and arch height are also important factors affecting print quality. Actual experimental testing showed that 4-6 arch layers, a 4 cm span, and an arch height of 0.8-1.0 mm yielded the most satisfactory print results. After printing the first arch layer, the curvature of each subsequent arch layer gradually decreases, and after 4-6 layers, the print returns to a normal horizontal bridging configuration.

[0062] The virtual entity model is printed using conventional 3D printing methods, generating an original G-code file. The G-code for the added bridging support structure or the arched printing structure is then replaced or inserted into the original G-code file. The G-codes from both printing methods are interwoven to obtain a printable G-code file. In actual production, 3D printing is performed directly based on the obtained G-code file to obtain a preliminary model. This preliminary model contains the bridging support structure or the arched printing structure. Removing the bridging support structure yields the printed part containing the kinematic mechanism, completing the printing process.

[0063] like Figure 5As shown, the main purpose of arched printing is to prevent long-distance bridging from sinking and hindering the movement of the mechanism. Traditional FDM 3D printing, with the printed material supporting both ends, allows the filament to resist gravity over a short distance to complete suspended bridging printing. However, bridging printing is strictly limited in terms of distance. Figure 5 As shown in Figure a, printing a 50mm long bridge using standard printing methods results in a 1.7mm sinking, rendering the sliding mechanism malfunction. Therefore, printing components with sliding motion in an assembled state is highly likely to cause functional obstruction. The arched printing method proposed in this invention, however, allows the printing filaments to cool and solidify during the sinking process due to its vertically undulating printing path, reducing the impact of gravity. Figure 5 Figure b shows the effect of printing a sliding mechanism using the arch printing method. It can be seen that the final 50mm long bridge did not sink, and the mechanism can work normally. Figure 5 The image in Figure d shows the printed result of an 80mm long arch bridge compared to traditional bridging methods. Figure 5 The contrast effect of c) in the middle.

[0064] The above are only some embodiments of the present invention. In fact, the bridging support structure and arched printing structure involved in the present invention can be set at any position where printing assistance is desired, according to actual printing needs. Furthermore, the bridging support structure and arched printing structure can be flexibly combined or selected. Therefore, the method of the present invention can produce complex motion structures with different deformation modes and steady-state control. According to some embodiments of the present invention:

[0065] The method of this invention can be used to print single-degree-of-freedom deformable structures, such as... Figure 6 As shown, taking rotational, sliding, and spiral motion units as examples, arched printing can prevent the suspension structure at the connection between two components from sagging, thus printing horizontal and neat gaps for smooth motion. In addition, using bridging supports and arched printing can also achieve integrated printing of multi-stable structures, such as... Figure 7 As shown, the multistability of rotational and sliding motions is utilized to integrate them into the parametric design system. Figure 7 The shaft hole in the structure shown in Figure a is a polygonal columnar structure, and the number of steady states is determined by the number of sides of the polygon. Figure 7 The protrusion shown in diagram b is used to control the sliding movement. When the slider slides above the protrusion, the protrusion is pressed down to fill the gap below, thereby reducing wear, improving stability, and increasing the lifespan of the joint. For large-size structures, integrated printing overcomes the size limitations of the printer platform by integrating multiple units. For example... Figure 8 As shown, the cuboid printed using this invention integrates a double-track structure, which expands the deformation range of the basic sliding unit.

[0066] The following is based on Figure 9 Taking the toy hedgehog shown as an example, the prototype of its spiky compressed structure includes the following steps:

[0067] 1. Input Model: The user inputs a hedgehog model with thorns;

[0068] 2. Model Setup: Simplify the model into a quadrilateral mesh, dividing the hedgehog into multiple parts such as the body and spines.

[0069] 3. Model Analysis: Analyze the connection parts of the model, using bridging support structures to support each spike, and using arches...

[0070] The structural design of the connecting rods is optimized to prevent them from sticking to the barbs during the printing process;

[0071] 4. G-code generation: Calculate the required number of bridging supports and arch layers, and generate the G-code for printing the bridging supports and arch structures;

[0072] 5. G-code integration: Slice to obtain the G-code of the original input model, and replace or insert the G-code of the bridge support and arch structure printed by the software into the corresponding positions in the original G-code;

[0073] 6. Manufacturing: Stacking and printing using common 3D printers, such as... Figure 9 b;

[0074] 7. Manual Transformation: Manually mimic the behavior of a hedgehog when startled; the sliding motion of the body causes it to retract its head, and all the quills stand up, assuming a defensive posture. Figure 9 c, 9d).

Claims

1. An integrated 3D printing method for kinematic mechanisms, characterized in that, The method includes two parts: software generation and actual production. The software generation is used to analyze the model containing kinematic mechanisms to determine the locations that need to be assisted in printing, and to add bridging support structures or use arched printing structures at the locations that need to be assisted in printing, thereby generating G-code files that can be directly used for printing. The actual production process includes 3D printing based on G-code files to obtain a preliminary model. The preliminary model contains a bridging support structure or a structure implemented using arch printing. The bridging support structure is then removed to obtain a printed part containing a kinematic mechanism, thus completing the printing process. The addition of the bridging support structure includes adding a "bridge-shaped" bridging support structure at the specified location. During actual printing, both ends of the bridging support structure must be placed on the already printed part to support the part belonging to the grid surface at the specified location. The arched printing structure includes: slicing the location horizontally from bottom to top, replacing the bottom slice with an arch, and gradually decreasing the curvature of the arches of each upward slice until the top slice is a horizontal structure.

2. The integrated 3D printing method for kinematic mechanisms according to claim 1, characterized in that, The software generation includes: Input Model: The user inputs any virtual entity model as a base; kinematic mechanism parts are set on the virtual entity model according to the required deformation position and motion requirements; Model setup: The obtained model is simplified into a quadrilateral mesh. Then, the user can adjust the motion mode and range of motion of the kinematic mechanism, control the gap range between the parts in the kinematic mechanism, and preview the completed model. Model Analysis: Analyze the obtained model. For parts that are attached to the 3D printing platform during actual printing, use conventional 3D printing methods directly. For parts that are not attached to the 3D printing platform during actual printing, determine the positions that require auxiliary printing and the methods of auxiliary printing. The auxiliary printing methods include adding bridging support structures or using arched printing structures.

3. The integrated 3D printing method for kinematic mechanisms according to claim 2, characterized in that, For parts that are not attached to the 3D printing platform during actual printing, the location and method of auxiliary printing are determined. Specifically, this includes: analyzing each mesh surface of the part; if a mesh surface is located on the bottom surface of the part and its normal vector forms an angle with the vertical direction, and the angle is less than a first preset value, or if the mesh surface is located on the bottom surface of the suspended structure part of the part and its normal vector forms an angle with the vertical direction, and the angle is less than a first preset value, then the auxiliary printing method of adding a bridging support structure is adopted for the mesh surface location; if the normal vector of the bottom surface of the suspended structure part of the part is vertical, then the suspended structure part adopts the auxiliary printing method of an arched printing structure.

4. The integrated 3D printing method for kinematic mechanisms according to claim 3, characterized in that, The addition of the bridging support structure further includes: for the component to which the grid surface belongs, sliced ​​horizontally from bottom to top, for each increase of the height by a second preset value, a "bridge-shaped" bridging support structure is added in the geometric center direction of the corresponding slice, and both ends of the bridging support structure must be placed on the already printed component during actual printing.

5. The integrated 3D printing method for kinematic mechanisms according to claim 1, characterized in that, The bottommost slice is replaced with an arch shape, and the arch curve is as follows: ， Where the length of the slice is taken as the x-direction, the upward direction as the z-direction, x is the x-coordinate, Z(x) is the z-height, r is the arch height, s is the span, and l p The width in the x-direction of the horizontal connecting sections on both sides of the arched structure.

6. The integrated 3D printing method for kinematic mechanisms according to claim 1, characterized in that, The method for generating the G-code file includes the following steps: printing a virtual entity model using conventional 3D printing methods to generate the original G-code file; replacing or inserting the G-code of the added bridging support structure or the arched printing structure into the original G-code file; and weaving the G-codes of the two printing methods together to obtain a G-code file that can be directly printed.

7. The integrated 3D printing method for kinematic mechanisms according to claim 1, characterized in that, The printing parameters for the bridging support structure are: PLA material, extrusion ratio per unit length of 1.2, and printing speed of 20 mm / s.

8. An integrated 3D printing system for kinematic mechanisms, characterized in that, The system is used to implement the software generation portion of the method as described in any one of claims 1-7.

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