Universal 3D printer and printing method thereof

Abstract

A universal 3D printer comprises a printer body and a control system, the printer body comprises a lower mold and an upper mold with a flat plate cavity, the lower mold and the upper mold are matched with each other, the lower mold comprises a base and a plurality of transmission assemblies, the transmission assemblies are arranged at intervals, and each transmission assembly comprises a moving rod and a transmission part which are coaxially arranged; the transmission parts are rotatably or fixedly installed on the base, the moving rods move up and down through the transmission parts, the upper ends of the moving rods are connected with the top heads, and the top heads jointly form a working area. The control system comprises a printing execution module, and the control end of each transmission part is electrically connected with the signal output end of the printing execution module. The foam package can be prefabricated based on the 3D model without relying on a real object, the problem that the package cannot be prefabricated in the product design, research and development stage is effectively solved, and the period from product design to package mass production is greatly shortened. The invention further provides a printing method of the universal 3D printer.

Description

Technical Field

[0001] The present invention relates to the technical field of foam material molding, and more particularly to a universal 3D printer and a printing method thereof. Background Art

[0002] At present, foam packaging is generally done manually, and the specific operation process is: laying an isolation film 1 on the bottom of the packaging box, and then placing the object to be packaged with the front side facing up on the isolation film 1, and then placing an isolation film 2 on the object, and adding a foaming agent to this isolation film 2, and the isolation film 2 completely covers it, and pressing the isolation film 2 so that the isolation film 2 is pressed tightly against the front side of the object, so that after the foaming agent foams, a foam packaging half can be obtained, and the foam packaging half has a cavity in the shape of the front side of the object, and then a foam packaging half with a cavity in the shape of the back side of the object can be obtained in the above manner, and the two foam packaging halves are folded together to form a foam packaging box, which can be used to place objects and avoid damage to the objects.

[0003] However, the foam packaging box obtained by the above operation method requires that the physical object has been produced. If the physical object has not yet been produced or is in the design and development stage, the foam packaging cannot be prefabricated, resulting in an extension of the product cycle from design to packaging mass production; moreover, manual operation is relatively cumbersome, time-consuming and labor-intensive, with low production efficiency, and it is difficult to meet the needs of large-scale production.

[0004] In view of this, the applicant conducted in-depth research on this basis, which led to the emergence of this case. Summary of the Invention

[0005] The purpose of the present invention is to provide a universal 3D printer and a printing method thereof, which can directly perform rapid prototyping of foam packaging based on a digital model of a product without relying on the physical object, effectively shortening the production cycle and improving production efficiency.

[0006] To achieve the above object, the solution of the present invention is: A universal 3D printer includes a printer body and a control system, wherein the printer body includes a lower mold and an upper mold having a flat cavity that cooperate with each other, the lower mold includes a base and a plurality of transmission assemblies arranged up and down, the transmission assemblies are arranged at intervals, and each transmission assembly includes a coaxially arranged moving rod and a transmission member, each transmission member is rotatably or fixedly mounted on the base, each moving rod is moved up and down by the transmission member, and the upper end of each moving rod is connected to a head, and each head together forms a working area; the control system includes a printing execution module, and the control end of each transmission member is electrically connected to the signal output end of the printing execution module.

[0007] Each of the transmission members is a screw rod, and a number of mounting holes and through holes are respectively provided on the base, and each of the mounting holes and the through holes correspond to each other one by one. Each of the transmission members can be rotatably installed in the corresponding mounting hole, and each of the moving rods is installed in the through hole in a manner of sliding up and down, and an internal thread section is respectively provided on the inner side wall of each of the moving rods, and the external thread section on each of the transmission members is spirally matched with the corresponding internal thread section; wherein, each of the transmission members is respectively equipped with a driving motor, and each of the driving motors is respectively installed on the lower side of the base, and the output shaft of each of the driving motors is respectively connected to the lower end of the corresponding transmission member, and the control end of each of the transmission members is respectively the control end of the corresponding driving motor.

[0008] Each of the transmission parts is a hydraulic cylinder, and a number of mounting holes are respectively opened on the base. The cylinder body of each hydraulic cylinder is respectively fixedly installed in the corresponding mounting hole, and the piston rod of each hydraulic cylinder is respectively connected to the lower end of the corresponding moving rod; wherein, each of the hydraulic cylinders is respectively connected to at least one hydraulic pump through a pipeline, and a control valve is respectively installed on each of the pipelines, and the signal input end of each control valve is respectively electrically connected to the signal output end of the printing execution module, and each of the hydraulic pumps is electrically connected to the signal output end of the printing execution module, and the control end of each of the transmission parts is respectively the control end of the corresponding control valve.

[0009] A printing method for a 3D universal printer, using the above-mentioned universal 3D printer, is performed according to the following steps: Step 1: Wrapping: Wrapping the 3D model of the object to be packaged; Step 2: Selecting a placement angle: Selecting a cross-section of the 3D model processed in step 1, and using the surface with the most bearing points as the downward-facing load-bearing surface. Then, determining the placement angle of the object to be packaged based on the load-bearing surface to form the optimal posture of the 3D model. Step 3: Obtain 3D packaging materials, obtain bounding box data of the optimal posture of the 3D model and process the data of the optimal posture of the 3D model to obtain the required 3D data of the packaging material, thereby generating a preset 3D packaging material; Step 4: Obtain a cross-sectioned 3D packaging material, perform cross-section processing on the preset 3D packaging material according to the cross section selected in step 2 to obtain two cross-sectioned 3D packaging materials, and then perform fine segmentation processing on the two cross-sectioned 3D packaging materials respectively; Step 5: The two cross-sectioned 3D packaging materials after fine segmentation processing are transmitted to the printing execution module, and the printing execution module is used to control each of the transmission components to complete the batch printing and forming of the packaging materials according to the preset trajectory, and finally obtain two cross-sectioned packaging materials that are adapted to the object to be packaged. After combination, a stable packaging box for the object to be packaged can be realized.

[0010] In step 1, the wrapping process includes simplifying precision and filling gaps, which involves reducing the details of the 3D model to simplify the 3D model precision and filling holes and / or gaps on the surface of the 3D model that are smaller than a manually preset value.

[0011] In step 2, an automatic recognition method is used to obtain the surface with the most bearing points in the 3D model. The steps of the automatic recognition method are as follows: Step A2-1: Generate the normal vectors and areas of all surfaces of the 3D model, and calculate the area score using the area score formula: S a = , where K a is the area coefficient, K a = ; is the contact area between the 3D model and the selected surface; Minimum area to maintain basic stability; K a,min is the critical stability value, K a.max is the ideal stable value; Step A2-2: Calculate the moment score using the moment score formula. The moment score formula is: S m = , where is the torque ratio, The torque to maintain the system's equilibrium is is the moment that pushes the system into instability; K m,min is the critical stability value, K m.max is the ideal stable value; Step A2-3: Perform contact stability scoring on all surfaces of the 3D model. The contact stability score is calculated using the following formula: S=α*S m +(1-α)*S a , where α is the moment weight, and 0< α <1; then, select the surface with the largest contact stability score as the load-bearing surface that needs to be arranged facing downward.

[0012] In step 2, an automatic placement angle method is used to determine the placement angle of the 3D model. The automatic placement angle method is to rotate the 3D model so that the surface normal vector of the load-bearing surface selected in step A2-3 is aligned with the z-axis.

[0013] When the selected load-bearing surface is an incomplete plane, polygonal plane fitting is performed on the load-bearing surface, and the normal of the fitted plane is aligned with the z-axis. The placement angle of the 3D model is secondary optimized. The secondary optimization process is as follows: the position of the 3D model determined by the automatic placement angle method is used as the initial placement position. Based on the initial placement position, the rotation combinations of 0°, 90°, 180° and 270° of the 3D model in the x-, y- and z-axis directions are traversed, and the envelope volume of each group of the rotation combinations is calculated. The rotation combination with the smallest envelope volume is selected as the optimal posture of the 3D model.

[0014] In step 4, if one of the two cross-sectioned 3D packaging materials has a size that is larger than the working size of the working area, the cross-sectioned 3D packaging material is bisected along an axis perpendicular to the excess size, so as to further cross-section the cross-sectioned 3D packaging material to obtain two 3D subdivided cross-sectioned packaging materials; When the size of the bisected 3D packaging material exceeds the working size of the working area along the x-axis, the bisected 3D packaging material is bisected along a direction perpendicular to the y-axis; When the size of the bisected 3D packaging material exceeds the working size of the working area along the y-axis, bisecting the bisected 3D packaging material along the x-axis; When the packaging material size of the cross-sectioned 3D packaging material exceeds the working size of the working area along the z-axis direction, the cross-sectioned 3D packaging material is cross-sectioned along the horizontal plane formed by the x-axis and the y-axis.

[0015] After step 4, first correspond the coordinates of the cross-sectioned 3D packaging material on the x and y axes to the x and y axis coordinates on the corresponding heads one by one, then obtain the values ​​of the n z-axis directions of the cross-sectioned 3D packaging material arranged in the x and y matrix, and obtain the height difference between each of the values ​​and the height value of the cross-sectioned 3D packaging material, and then the printing execution module converts the height difference values ​​arranged in the x and y matrix into electrical signals and sends them to the control ends of the transmission parts, so that each head moves to the target position to form a curved surface matching the cavity of the cross-sectioned 3D packaging material. At the same time, the control system controls the upper mold to move downward, and presses the isolation film laid in the working area and the foaming material covered in the isolation film to complete the printing of the cross-sectioned 3D packaging material.

[0016] After adopting the above scheme, the present invention has the following beneficial effects: the present invention adopts the steps of package processing, placement angle selection and 3D packaging material bisection to complete the packaging material data processing, and then according to the data of the 3D packaging material bisection, the printing execution module controls the action of the transmission component, and cooperates with the upper mold to realize the layered printing and molding of the packaging material; compared with the traditional manual foaming packaging method, the present invention does not rely on the physical object to prefabricate foaming packaging based on the 3D model, effectively solving the problem of inability to prefabricate packaging in the product design and development stage, and greatly shortening the cycle from product design to packaging mass production; at the same time, the automated printing process replaces tedious manual operations, reduces manpower input, significantly improves production efficiency, and can better meet the needs of large-scale production.

[0017] Furthermore, in the placement angle selection step, the surface with the most bearing points is automatically identified as the load-bearing surface, and the optimal posture is selected in combination with the secondary optimized rotation combination. This not only improves the stability of the packaging, but also maximizes the use of the space in the packaging box and reduces the use of packaging materials.

[0018] Furthermore, the present invention's refined segmentation of 3D packaging materials and the two-way cutting strategy when they exceed the working area ensure that large packaging materials can also be printed and formed smoothly, avoiding the problem of being unable to produce due to the limited working size of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the structure of the printer body in the universal 3D printer of the present invention (the upper mold is omitted).

[0020] Figure 2 Schematic diagram of the structure of the transmission component in the universal 3D printer of the present invention.

[0021] Figure 3 Schematic diagram of a 3D model in the printing method of the universal 3D printer of the present invention.

[0022] Figure 4 Schematic diagram of a 3D model after wrapping processing in the printing method of the universal 3D printer of the present invention.

[0023] Figure 5 Schematic diagram of cross-section selection in the printing method of the universal 3D printer of the present invention.

[0024] Figure 6 Schematic diagram of obtaining preset 3D packaging materials in the printing method of the universal 3D printer of the present invention.

[0025] Figure 7 Schematic diagram of a cross-section of a preset 3D packaging material in the printing method of the universal 3D printer of the present invention.

[0026] In the picture: 1-lower die; 2-base; 21-bottom plate; 22-upper plate; 23-column; 3-transmission member; 4-moving rod; 5-head. DETAILED DESCRIPTION

[0027] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0028] A universal 3D printer is suitable for printing conventional foam packaging materials.

[0029] like Figure 1 As shown- Figure 2 As shown, the universal 3D printer includes a printer body and a control system. For the convenience of description, the orientation of the printer body during normal use is used as the reference direction of the present invention. The printer body includes a lower mold 1 and an upper mold (not shown in the figure) that cooperate with each other. The upper mold (not shown in the figure) is located on the upper side of the lower mold 1, and the lower side surface of the upper mold has a flat cavity. Preferably, the upper mold can move up and down. In detail, the upper mold adopts a moving device commonly used in existing conventional molds to move up and down through the moving device, and the upper mold is installed on the bracket through the moving device. The moving device can be a hydraulic cylinder device, a screw device, etc. The bracket can be an N-shaped bracket fixedly installed on the flat ground or on the base of the lower mold 1 described below.

[0030] The above-mentioned lower mold 1 includes a base 2 and several transmission components, each transmission component is arranged up and down, and each transmission component is arranged evenly at intervals. Preferably, each transmission component is arranged in a matrix, and each transmission component includes a transmission member 3 and a moving rod 4. The lower end of the transmission member 3 can be rotatably or fixedly installed on the base 2, and each moving member 4 moves up and down through the corresponding transmission member 3. Each transmission member 3 and the moving rod 4 are coaxially arranged, and the two can be connected together in conventional ways such as couplings, tight sleeves, snap fits or threaded connections.

[0031] Furthermore, a plug 5 is installed on the upper end of each movable rod 4, each plug 5 is spherical, and each plug 5 together forms a working area for carrying and forming packaging materials. The shape of the working area can be dynamically adjusted by controlling the movement of different transmission parts 3 to adapt to the following 3D packaging material printing requirements of different shapes; preferably, each plug 5 is rotatably installed on the upper end of the corresponding movable rod 4, and the two can be installed together by conventional methods such as clearance fit or key connection to ensure that the plug 5 can flexibly adjust the angle when cooperating with the upper mold to press the packaging material, so as to avoid scratches or indentations on the surface of the packaging material.

[0032] It is worth mentioning that during the packaging material printing process, an isolation film (such as a plastic film) is usually laid on the working area to facilitate the separation of the packaging material from the working area. Therefore, two adjacent heads 5 can be spliced ​​with each other, or they can be gap-matched to facilitate the movement of each transmission component. At the same time, due to the effect of the isolation film, the foaming material is prevented from leaking from the gap between the heads 5 during the molding process.

[0033] In this embodiment, the above-mentioned control system includes a printing execution module, and the control end of each transmission member 3 is electrically connected to the signal output end of the printing execution module, so that the action of each transmission member 3 can be controlled by the printing execution module, thereby driving each head 5 to move up and down.

[0034] Furthermore, the above-mentioned base 2 includes a bottom plate 21, an upper plate 22 located on the upper side of the bottom plate 21, and several columns 23 connecting the bottom plate 21 and the upper plate 22. The columns 23 are arranged at the four corners between the bottom plate 21 and the upper plate 22, and each transmission component is respectively located within the encirclement of the base 2; in addition, the upper plate 22 can also be replaced with a frame according to actual conditions.

[0035] Furthermore, each of the above-mentioned transmission members 3 is moved up and down using a moving device, and the specific structure of the moving device is described as follows.

[0036] In the first structure, each transmission member 3 is a screw rod, that is, the outer side wall of each transmission member 3 is respectively provided with an external thread section, and a plurality of mounting holes are respectively opened on the outer base 2, and each mounting hole and each transmission member 3 are respectively matched one to one, and each transmission member 3 is rotatably installed in the corresponding mounting hole. The transmission member 3 can be rotatably installed in the mounting hole by a key connection or by a conventional method such as a bearing; a moving rod 4 is respectively sleeved on each transmission member 3, and the above-mentioned upper plate 22 is respectively provided with a plurality of plate holes, and each plate hole and each moving rod 4 are respectively matched one to one, and a slide groove arranged along the axial direction is respectively opened on the hole wall of each plate hole. The outer side wall of each moving rod 4 is integrally connected with a sliding block arranged along the axial direction, and each moving rod 4 is slidingly limited with the sliding groove on the corresponding plate hole through its own sliding block, and the inner side wall of each moving rod 4 is respectively provided with an internal thread section, and the internal thread section on each moving rod 4 is spirally matched with the external thread section on the corresponding transmission member 3; wherein, each transmission member 3 is respectively equipped with a driving motor, and each driving motor is respectively fixedly mounted on the lower side of the base plate 21, and the output shaft of each driving motor is respectively connected to the lower end of the transmission member 3, and the two can be connected together by existing conventional methods such as couplings.

[0037] In this way, the up and down moving structures of each moving rod 4 are the same, so one of the moving rods 4 is taken as an example for explanation; when the driving motor is started, its output shaft drives the transmission part 3 to rotate. Since the moving rod 4 is matched with the sliding groove of the upper plate 22 through the sliding block, the moving rod 4 cannot rotate synchronously with the transmission part 3, and can only move up and down axially under the action of the threaded transmission of the transmission part 3, thereby driving the head 5 to move up and down, thereby adjusting the shape of the working area.

[0038] The second structure is that each transmission member 3 is a hydraulic cylinder, and a plurality of mounting holes are opened on the base plate 21. The cylinder body of each hydraulic cylinder is fixedly installed in the mounting hole, and the upper end of the piston rod of each transmission member 3 is integrally connected to the moving rod 4, and each moving rod 4 is located within the frame surrounding range of the above-mentioned base 2, wherein each transmission member 3 is connected to at least one hydraulic pump through a pipeline, and a control valve is installed on each pipeline, and the signal input end of each control valve is electrically connected to the signal output end of the printing execution module, and the control end of each hydraulic pump is electrically connected to the signal output end of the printing execution module, where the control end of each transmission member 3 is the control end of the corresponding control valve; in this embodiment, the hydraulic pump is preferably a water pump.

[0039] Furthermore, a one-way valve is installed between each transmission member 3 and the control valve thereon to prevent water from flowing back on the transmission member 3. Each transmission member 3 is also connected to a water pump through a pipeline. At least one of the water pumps can be provided so that after the printer body completes printing, the water on the transmission member 3 can be pumped out through the water pump, so that each transmission member 3 drives the corresponding moving rod 4 to return to its position.

[0040] In this embodiment, each transmission member 3 is hydraulically driven, so a conventional hydraulic system is also provided outside the base 2, such as a water tank, a reversing valve, etc. This part adopts existing conventional operations and will not be described in detail.

[0041] Furthermore, in this embodiment, the number of water pumps can be at least one, that is, one water pump controls the movement of all transmission parts 3. Alternatively, all transmission parts 3 can be divided into multiple parts, with one water pump responsible for one part. Alternatively, each transmission part 3 can be equipped with a water pump. The specific configuration of the water pump is determined according to actual conditions and is not set here.

[0042] It should be noted that after each transmission member 3 drives the corresponding moving rod 4 to move up and down according to actual conditions, the backflow of water can make each plug 5 return to its position. However, sometimes when the plug 5 does not return to its position, the corresponding plug 5 can be pressed down manually to return to its position.

[0043] In this way, the up and down movement structure of each moving rod 4 is the same, so one of the moving rods 4 is taken as an example for explanation; when it is necessary to control the transmission assembly to drive the head 5 to move up and down, the printing execution module sends a control signal to the corresponding control valve, the control valve adjusts the opening according to the signal, and the hydraulic pump pumps hydraulic water (or oil) into the cylinder of the transmission part 3, pushing the piston rod to extend, and then driving the moving rod 4 and the head 5 to move upward; when the head 5 needs to move downward, the printing execution module controls the control valve to move in the opposite direction, the hydraulic water (or oil) in the transmission part 3 flows back, and the piston rod retracts under the action of gravity or spring force to drive the moving rod 4 to move synchronously, thereby realizing the downward movement of the head 5 to ensure that the shape of the working area meets the forming requirements of the following 3D packaging materials. In the present invention, each movable rod 4 can be moved up and down according to different types and specifications of foam packaging, and has strong versatility.

[0044] The control system further includes a signal processing unit, which is used to receive external input 3D model data of the object to be packaged, process the 3D model data according to a preset algorithm, and generate control instructions to send to the printing execution module.

[0045] During the actual working process, the user imports the 3D model of the object to be packaged into the control system or generates a 3D model in the 3D module of the control system. The signal processing unit first wraps the 3D model, such as simplifying the accuracy, filling the gaps, etc., and then automatically identifies the load-bearing surface and optimizes the placement angle, and then generates data; after that, the printing execution module controls the action of each transmission part 3 according to the processed cross-section 3D packaging material data, so that the top head 5 forms a shape that matches the part of the cross-section 3D packaging material for accommodating the object to be packaged. At the same time, the control system controls the upper mold to move downward, and presses the isolation film and foaming material laid on the top head into shape to complete the printing of the corresponding packaging material; repeating the above process can obtain a complete foam packaging material.

[0046] The present invention also provides a general 3D printer printing method, such as Figure 3 As shown- Figure 6 As shown, the printing method includes the following steps: Step 1: Perform 3D modeling on the object to be packaged to obtain a 3D model of the object to be packaged, and then perform packaging processing on the 3D model.

[0047] Specifically, if Figure 3 As shown, the above 3D modeling can be performed in the control system of the printer body, and the control system also includes a 3D module. It can also be generated in 3D software and then imported into the control system. The two can be selected according to actual conditions.

[0048] Furthermore, wrapping includes simplifying precision and gap filling, e.g. Figure 4As shown, in the simplified precision, the details of the 3D model are slightly reduced to reduce the complexity of the 3D model. The details of the 3D model here can be rounded corners, simplified surfaces, etc., so as to improve processing efficiency.

[0049] Among them, when the 3D model is a visual model, its accuracy error range is ±1~2mm, that is, the accuracy range can be slightly reduced to ±1~2mm; if the 3D model is a functional protection model, the accuracy error range is ±0.5mm, that is, the accuracy range can be slightly reduced to ±0.5mm; in this embodiment, the accuracy adjustment of the above-mentioned 3D model can be achieved by conventional operations, so it will not be described in detail.

[0050] In gap filling, a preset value is manually set, which can be preset in the control system. Holes and / or gaps smaller than the preset value on the surface of the 3D model are filled to avoid missing packages when the packaging material is generated. Holes and / or gaps smaller than 2-3mm in the 3D model are automatically closed or bridged. This closing or bridging process can be achieved using conventional Boolean hole filling algorithms or STL model repair tools.

[0051] Step 2: Select the placement angle. Select the section of the 3D model after step 1. Figure 5 As shown, the surface with the most bearing points in the 3D model is used as the downward-facing load-bearing surface, and then the placement angle of the 3D model is determined based on the load-bearing surface.

[0052] To elaborate, an automatic recognition method is used to obtain the face with the most bearing points in a 3D model. The automatic recognition method includes the following steps: Step A2-1: Obtain all surfaces of the 3D model, generate the surface normal vectors and areas of all surfaces of the 3D model, and calculate the area score using the area score formula. The area score formula is: S a = , where K a is the area coefficient, K a = , is the contact area between the 3D model and the selected surface; The minimum area to maintain basic stability can be determined through experiments or theoretical calculations; K a The bigger, the more stable; K a,min is the critical stability value, usually set to 1, that is, A = When just stable; K a.maxIt is the ideal stable value and can be set according to the requirements.

[0053] Step A2-2: Simulate the direction of gravity to estimate the moment of each face of the 3D model. Here, the direction of gravity is the z-axis. The moment score is calculated using the moment score formula. The moment score formula is: S m = , where is the torque ratio, which quantifies the contribution of torque to stability and is usually taken as K m = , in, >1 indicates temporary stability, the larger the value, the more stable it is; The torque to maintain the system's equilibrium is is the moment that pushes the system into instability; K m,min is the critical stability value, usually set to 1 (critical stability when torque is balanced); K m.max It is the ideal stable value and is set according to the application scenario.

[0054] Step A2-3: Perform contact stability scoring on all surfaces of the 3D model. The contact stability score is calculated using the following formula: S=α*S m +(1-α)*S a , where α is the moment weight, and 0< α <1; then, select the surface with the largest contact stability score as the load-bearing surface that needs to be arranged facing downward.

[0055] In this embodiment, α You can choose to set it according to the actual situation, such as setting it to 0.7. For example, taking "objects on the table resist tipping" as an example, the specific construction process is: 1. Torque parameter: stable torque M s =G*d , where G is the object's gravity, d is the minimum distance from the center of gravity to the support edge; the destabilizing moment M u =F*h , F is the lateral force, h is the force height; torque ratio K m = .

[0056] 2. Area parameter: support area A , area coefficient Ka = , a is the length of the bottom side of the object.

[0057] 3. Scoring function: If lateral force is the main threat, then α =0.7, then S =0.7* S m +0.3* S a ,in, S The closer it is to 1, the better the stability.

[0058] Furthermore, an automatic placement angle method is used to determine the placement angle of the 3D model. The automatic placement angle method is: rotating the 3D model so that the surface normal vector of the load-bearing surface selected in step A2-3 is aligned with the z-axis.

[0059] When the load-bearing surface selected in step A2-3 is an incomplete plane, a polygonal plane fitting is performed on the load-bearing surface, and the surface normal (i.e., the surface normal vector) of the fitted plane is aligned with the z-axis. It should be noted that the above-mentioned section selection is generally to perform a bisection of the 3D model. In this step, only the section of the 3D model is selected, but no bisection is performed.

[0060] As a preferred method, the placement angle of the 3D model is optimized twice to save packaging box space. The process of the secondary optimization is as follows: The position of the 3D model determined using the automatic placement angle method is used as the initial placement position. Based on this initial placement position, the 3D model is rotated in the x, y, and z directions by 0°, 90°, 180°, and 270°, respectively, for a total of 64 rotation combinations. The enveloping volume of each rotation combination is calculated, and the rotation combination with the smallest enveloping volume is selected as the optimal pose of the 3D model. It should be noted that in this embodiment, the enveloping volume size is calculated using the conventional minimum bounding cuboid (OBB) method. Alternatively, the enveloping volume size can be calculated using the conventional axis-aligned bounding box (AABB) method or other conventional methods.

[0061] In addition, the optimal posture of the 3D model can also be selected by calculating the volume utilization rate. The formula for volume utilization rate is: volume utilization rate = volume of 3D model / bounding box volume of 3D model. The rotation combination with the largest volume utilization rate is selected as the optimal posture, where the bounding box volume of each rotation combination is calculated using a conventional method, such as AABB (axis-aligned bounding box) volume calculation, which is to traverse all vertices in each rotation combination, find the minimum and maximum values ​​of the x, y, and z coordinates, and then calculate the lengths of the three sides and multiply them to obtain the volume. In addition, the conventional OBB (oriented bounding box) volume calculation or the bounding sphere (Bounding Sphere) volume calculation can also be used.

[0062] Step 3: Perform Boolean operation on the bounding box data of the optimal posture of the 3D model and the data of the optimal posture of the 3D model in step 2 to obtain the required 3D packaging material data, and generate the preset 3D packaging material, that is, Figure 6 shown.

[0063] In this embodiment, the above-mentioned Boolean operation is a conventional operation, and thus will not be described in detail.

[0064] Step 4: Use the section selected in step 2 to perform cross-section processing on the preset 3D packaging material in step 3 to obtain two cross-section 3D packaging materials. The two cross-section 3D packaging materials are arranged up and down, and then the two cross-section 3D packaging materials are finely subdivided, that is, Figure 7 shown.

[0065] It should be noted that the section selection in step 2 generally selects the largest flat surface in the 3D model as the dividing interface. The section is a plane, so the upper mold adopts an upper mold with a flat cavity; in this embodiment, the part that needs to be adjusted is the cavity shape of the lower mold, that is, the shape of the working area of ​​the printer body.

[0066] Furthermore, if the packaging size of one or both of the two cross-sectioned 3D packaging materials is larger than the working size of the working area of ​​the printer body, if the packaging size of one of the cross-sectioned 3D packaging materials exceeds, the cross-sectioned 3D packaging material is cut into two parts along the axis perpendicular to the exceeded size, so that the cross-sectioned 3D packaging material is cut into two 3D subdivided cross-sectioned packaging materials; accordingly, if the packaging size of two cross-sectioned 3D packaging materials exceeds, the two cross-sectioned 3D packaging materials are cut separately in the above manner.

[0067] When the packaging material size of the cross-sectioned 3D packaging material exceeds the working size of the working area along the x-axis direction, the cross-sectioned 3D packaging material is cross-sectioned along a direction perpendicular to the y-axis.

[0068] When the packaging material size of the split 3D packaging material exceeds the working size of the working area along the y-axis direction, the split 3D packaging material is split along the x-axis direction.

[0069] When the packaging material size of the cross-sectioned 3D packaging material exceeds the working size of the working area along the z-axis direction, the cross-sectioned 3D packaging material is cross-sectioned along the horizontal plane formed by the x-axis and the y-axis.

[0070] It is worth mentioning that the above steps can be generated in the corresponding software, that is, each 3D segmented packaging material can generate a packaging material 3D file respectively, and then be imported into the control system and printed separately; in addition, the above steps can also be generated in the control system.

[0071] Among them, each two adjacent 3D subdivided packaging materials can be provided with alignment slots or edge chamfers to facilitate subsequent splicing. In addition, the size of the packaging box is cut according to the size of the packaging material, and the adjacent packaging materials can be arranged close together when placed in the packaging box.

[0072] It should be noted that the above-mentioned subdivision method can be combined with a conventional automatic segmentation algorithm, such as Voxel cutting or KD-Tree space partitioning method, to optimize the generated path.

[0073] Furthermore, the refined segmentation processing in this embodiment is an existing conventional refined segmentation processing method.

[0074] Step 5. The two cross-sectioned 3D packaging materials after fine segmentation processing are respectively transmitted to the printing execution module. The printing execution module works twice according to the corresponding cross-sectioned 3D packaging materials. When printing each cross-sectioned 3D packaging material, the printing execution module controls the control end of each transmission part and completes the layered printing and forming of the packaging material according to the preset trajectory. Finally, two cross-sectioned packaging materials that are compatible with the object to be packaged are obtained. After combination, a stable packaging box for the object to be packaged can be realized.

[0075] Specifically, in the printer body, each head 5 is provided with three-dimensional coordinates, namely, x-, y-, and z-axis coordinates. In the initial state, the working area formed by each head 5 is a horizontal plane.

[0076] Among them, the printing process of the two cross-sectional 3D packaging materials is the same, so one of the cross-sectional 3D packaging materials is taken as an example for explanation. For the convenience of description, the cross-sectional 3D packaging material is recorded as the first cross-sectional 3D packaging material, and the other is the second cross-sectional 3D packaging material.

[0077] During the printing process, the coordinates of the first cross-sectional 3D packaging material on the x and y axes are first mapped to the x and y axis coordinates on the corresponding pin 5 one by one, and then the n z-axis values ​​of the first cross-sectional 3D packaging material arranged in the x and y matrix are obtained, and the height difference between the n values ​​and the height of the first cross-sectional 3D packaging material is obtained. The height difference is the height value that the corresponding pin 5 needs to extend; wherein, n refers to the number of pins 5 to be moved according to the first cross-sectional 3D packaging material, and the height refers to the value from the bottom surface to the cross section of the packaging material.

[0078] Then, the printing execution module converts the height differences of the first cross-sectioned 3D packaging material in the x, y matrix arrangement into electrical signals and sends them to the control end of each transmission member 3, so that each head 5 can be accurately moved to the target position to form a curved surface that matches the cavity of the first cross-sectioned 3D packaging material. Subsequently, the control system controls the upper mold to move downward, presses the isolation film laid in the working area and the foaming material wrapped in the isolation film, and uses the expansion characteristics of the foaming material to fill the cavity space. After the material is solidified and formed, the upper mold is reset and the head 5 returns to its position to complete the printing of the first cross-sectioned 3D packaging material.

[0079] In this embodiment, the printing process of the second bisected 3D packaging material is consistent with that of the first bisected 3D packaging material. It is only necessary to adjust the protruding height of each pin 5 according to its corresponding cavity data. Through the synergistic effect of layered printing and height control, it is ensured that the two bisected packaging materials finally formed can be seamlessly spliced ​​to provide a fitting buffer protection structure for the object to be packaged.

[0080] A printing method of the present invention adopts the steps of wrapping 3D models, optimizing placement angles, generating packaging material data through Boolean operations, sectioning and fine-tuning, etc., combined with the flexible driving mode of the transmission component, to achieve efficient molding of packaging materials of different specifications. It has strong versatility and does not rely on physical objects, which can effectively shorten the production cycle and improve production efficiency.

[0081] The above description is only a preferred embodiment of this embodiment, and all equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A general 3D printer, characterized by: It includes a printer body and a control system, the printer body includes a lower mold that cooperates with each other and an upper mold with a flat cavity, the lower mold includes a base and several transmission components arranged up and down, the transmission components are arranged at intervals, and each transmission component includes a coaxially arranged moving rod and a transmission member, each transmission member is rotatably or fixedly installed on the base, each moving rod is moved up and down by the transmission member, and the upper end of each moving rod is connected to a head, and each head together forms a working area; the control system includes a print execution module, and the control end of each transmission member is electrically connected to the signal output end of the print execution module.

2. A universal 3D printer according to claim 1, characterized in that: Each of the transmission members is a screw rod, and a number of mounting holes and through holes are respectively provided on the base, and each of the mounting holes and the through holes correspond to each other one by one. Each of the transmission members can be rotatably installed in the corresponding mounting hole, and each of the moving rods is installed in the through hole in a manner of sliding up and down, and an internal thread section is respectively provided on the inner side wall of each of the moving rods, and the external thread section on each of the transmission members is spirally matched with the corresponding internal thread section; wherein, each of the transmission members is respectively equipped with a driving motor, and each of the driving motors is respectively installed on the lower side of the base, and the output shaft of each of the driving motors is respectively connected to the lower end of the corresponding transmission member, and the control end of each of the transmission members is respectively the control end of the corresponding driving motor.

3. A universal 3D printer according to claim 1, characterized in that: Each of the transmission parts is a hydraulic cylinder, and a number of mounting holes are respectively opened on the base. The cylinder body of each hydraulic cylinder is respectively fixedly installed in the corresponding mounting hole, and the piston rod of each hydraulic cylinder is respectively connected to the lower end of the corresponding moving rod; wherein, each of the hydraulic cylinders is respectively connected to at least one hydraulic pump through a pipeline, and a control valve is respectively installed on each of the pipelines, and the signal input end of each control valve is respectively electrically connected to the signal output end of the printing execution module, and each of the hydraulic pumps is electrically connected to the signal output end of the printing execution module, and the control end of each of the transmission parts is respectively the control end of the corresponding control valve.

4. A printing method for a general 3D printer, characterized in that: Using the universal 3D printer as claimed in claim 2 or 3, printing is performed according to the following steps: Step 1: Wrapping: Wrapping the 3D model of the object to be packaged; Step 2: Selecting a placement angle: Selecting a cross-section of the 3D model processed in step 1, and using the surface with the most bearing points as the downward-facing load-bearing surface. Then, determining the placement angle of the object to be packaged based on the load-bearing surface to form the optimal posture of the 3D model. Step 3: Obtain 3D packaging materials, obtain bounding box data of the optimal posture of the 3D model and process the data of the optimal posture of the 3D model to obtain the required 3D data of the packaging material, thereby generating a preset 3D packaging material; Step 4: Obtain a cross-sectioned 3D packaging material, perform cross-section processing on the preset 3D packaging material according to the cross section selected in step 2 to obtain two cross-sectioned 3D packaging materials, and then perform fine segmentation processing on the two cross-sectioned 3D packaging materials respectively; Step 5: The two cross-sectioned 3D packaging materials after fine segmentation processing are transmitted to the printing execution module, and the printing execution module is used to control each of the transmission components to complete the batch printing and forming of the packaging materials according to the preset trajectory, and finally obtain two cross-sectioned packaging materials that are adapted to the object to be packaged. After combination, a stable packaging box for the object to be packaged can be realized.

5. The printing method of a universal 3D printer according to claim 4, characterized in that: In step 1, the wrapping process includes simplifying precision and filling gaps, which involves reducing the details of the 3D model to simplify the 3D model precision and filling holes and / or gaps on the surface of the 3D model that are smaller than a manually preset value.

6. The printing method of a universal 3D printer according to claim 4, characterized in that: In step 2, an automatic recognition method is used to obtain the surface with the most bearing points in the 3D model. The steps of the automatic recognition method are as follows: Step A2-1: Generate the normal vectors and areas of all surfaces of the 3D model, and calculate the area score using the area score formula: S a = , where K a is the area coefficient, K a = ; is the contact area between the 3D model and the selected surface; Minimum area to maintain basic stability; K a,min is the critical stability value, K a.max is the ideal stable value; Step A2-2: Calculate the moment score using the moment score formula. The moment score formula is: S m = , where is the torque ratio, The torque to maintain the system's equilibrium is is the moment that pushes the system into instability; K m,min is the critical stability value, K m.max is the ideal stable value; Step A2-3: Perform contact stability scoring on all surfaces of the 3D model. The contact stability score is calculated using the following formula: S=α*S m +(1-α)*S a , where α is the moment weight, and 0< α <1; Then, select the surface with the largest contact stability score as the load-bearing surface that needs to be arranged facing downward.

7. The printing method of a universal 3D printer according to claim 6, characterized in that: In step 2, an automatic placement angle method is used to determine the placement angle of the 3D model. The automatic placement angle method is to rotate the 3D model so that the surface normal vector of the load-bearing surface selected in step A2-3 is aligned with the z-axis.

8. The printing method of a universal 3D printer according to claim 7, characterized in that: The placement angle of the 3D model is secondary optimized. The secondary optimization process is as follows: the position of the 3D model determined by the automatic placement angle method is used as the initial placement position. Based on the initial placement position, the rotation combinations of 0°, 90°, 180° and 270° of the 3D model in the x-, y- and z-axis directions are traversed, and the envelope volume of each group of the rotation combinations is calculated. The rotation combination with the smallest envelope volume is selected as the optimal posture of the 3D model.

9. The printing method of a universal 3D printer according to claim 4, characterized in that: In step 4, if one of the two cross-sectioned 3D packaging materials has a size that is larger than the working size of the working area, the cross-sectioned 3D packaging material is bisected along an axis perpendicular to the excess size, so as to further cross-section the cross-sectioned 3D packaging material to obtain two 3D subdivided cross-sectioned packaging materials; When the size of the bisected 3D packaging material exceeds the working size of the working area along the x-axis, the bisected 3D packaging material is bisected along a direction perpendicular to the y-axis; When the size of the bisected 3D packaging material exceeds the working size of the working area along the y-axis, bisecting the bisected 3D packaging material along the x-axis; When the packaging material size of the cross-sectioned 3D packaging material exceeds the working size of the working area along the z-axis direction, the cross-sectioned 3D packaging material is cross-sectioned along the horizontal plane formed by the x-axis and the y-axis.

10. The printing method of a universal 3D printer according to claim 9, characterized in that: After step 4, first correspond the coordinates of the cross-sectioned 3D packaging material on the x and y axes to the x and y axis coordinates on the corresponding heads one by one, then obtain the values ​​of the n z-axis directions of the cross-sectioned 3D packaging material arranged in the x and y matrix, and obtain the height difference between each of the values ​​and the height value of the cross-sectioned 3D packaging material, and then the printing execution module converts the height difference values ​​arranged in the x and y matrix into electrical signals and sends them to the control ends of the transmission parts, so that each head moves to the target position to form a curved surface matching the cavity of the cross-sectioned 3D packaging material. At the same time, the control system controls the upper mold to move downward, and presses the isolation film laid in the working area and the foaming material covered in the isolation film to complete the printing of the cross-sectioned 3D packaging material.

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