TWI816163B - A system for manufacturing 3d objects and methods thereof - Google Patents

Abstract

A rapid prototyping and production system features a dispensing head capable of dispensing material from two connected but basically perpendicular exits, one for dispensing material in erected positions and one for dispensing material in horizontal positions. In general, the dispensing head of this invention comprises adjustable exit capable of changing cross-sectional area by a factor of at least 10 to 200 to accommodate variation of required geometric feature size and to increase build rate. Further, this invention includes a shaping tool for reshaping solidified dispensed material to improve curvature and surface finish. Still further, this invention includes a Thick-layer Building procedure, which builds a 3D object by repeatedly alternating a dispensing step to dispense a thick layer of material and a shaping step, using a shaping tool, to reshape the layer.

Description

A system and method for manufacturing 3D objects

The present invention relates to systems and methods for rapid 3D prototyping and production technology (rapid prototyping and production), and in particular to systems and methods for producing 3D prototypes, components and molds with better surface smoothness at a faster speed.

The current commercialized additive manufacturing technology mainly uses metal powder lamination method (Selective Laser Melting, SLM) in terms of metal forming. In terms of non-metal forming, it mainly includes stereolithography (Stereolithography, SLA) and fused deposition forming (Fused). Deposition Modeling (FDM), 3D Printing (3DP) and Laminated Object Manufacturing (LOM), etc. However, its practical application fields are not yet common. The reason is that the industry currently believes that the following shortcomings still need to be solved: (1) slow forming speed, (2) poor surface roughness, (3) material type restrictions and (4) ) Equipment and material costs are high.

The reason for the above-mentioned shortcomings is that the basic forming methods used by various current methods are in principle horizontally stacked fabrics and solidified and formed by connecting dots to form lines. Regardless of the geometric shape of the workpiece, horizontal lamination is always used when fabricating. Since the lamination has a certain thickness, when encountering characteristic structures such as curved surfaces and inclined planes, lamination steps will occur, which will worsen the surface roughness. However, during solidification, points are connected to form lines and then constructed into plane, three-dimensional and other structures, and single points are accumulated to form the required three-dimensional structure, resulting in Shape speed is slow. If the lamination thickness is reduced (that is, the lamination steps are reduced) in order to improve the surface quality of the curved surface, the forming speed will be significantly slowed down because the total time for dotting and horizontal lamination of fabrics will increase. Figure 1(a) is an example of a 3D part. Figure 1(b) and (c) illustrate the situation when it is manufactured using the current additive manufacturing technology. Figure 1(b) is an enlarged view of the blade part. Figure 1( c) is a cross-sectional diagram. The dotted line 201 is a cross-cutting lattice structure of horizontal lamination, and 217 and 218 are the material forming conditions of horizontal lamination. The outer walls of the blade 103 and the hub 102 will inevitably produce lamination steps, resulting in surface roughness differences (214, 212). The thick black curve 203 shows the scanning situation of connecting points to form a line and solidifying. The construction method of point writing is used, resulting in a slow forming speed. In terms of forming physics, each current method requires high-average particle size, high-fluidity metal powder (the cost is 7-8 times that of ordinary powder), photosensitive polymers, lasers, environmental control boxes and other related equipment, so the manufacturing cost is high. In order to achieve high forming density, metal powders of different particle sizes need to be mixed in different proportions, which is a complicated procedure.

Taking the SLM (or Selective Laser Sintering, SLS) method as an example, the surface roughness of the part is related to the angle of the laser molding path. Better surface roughness can be obtained on the vertical or parallel laser sintering plane. , the surface roughness of curved or inclined surfaces is subject to certain limitations [Amend, P.et al., "A fast and flexible method for manufacturing 3D molded interconnect devices by the use of a rapid prototyping technology", Journal of Physics Procedia, Volume 5 ,Part B,2010,Pages 561-572.]. Plastic injection molding mold cores made by SLM systems. Plastic injection molding mold cores made by SLM systems generally have a surface roughness of 40 microns (comparable to sand mold casting), and 200-500 microns need to be reserved for subsequent cutting. processing. There are also studies on using laser for polishing. Increasing the range of the laser's light spot can re-melt and solidify the surface metal again to achieve the polishing effect. However, this method consumes quite a lot of energy, so the cost is relatively high. And the result has not yet achieved the surface smoothness expected by the industry [A. Lamikiz et al., "Laser polishing of parts built up by selective laser sintering", International Journal of Machine Tools & Manufacture 47 (2007) 2040-2050].

In terms of increasing the forming speed, there is the so-called skin-core strategy, which uses a smaller laser spot to scan the contour and a larger laser spot to scan the interior, and even develops a multi-beam system to speed up the molding process. shape speed. However, these methods require expensive laser costs [K.Wissenbach, "Fantasia Project Shows Selective Laser Melting Can Produce Complex Components Quickly and Cost Effectively", http://www.ineffableisland.com/2010/05/fantasia-project -shows-selective-laser.html? showComment=1318241730096].

Regarding the FDM method, US Pat. No. 5,121,329 discloses the use of a cloth head to move along a curve in space to produce a curved surface or curved frame (original Figures 10 and 12 in the patent). The patent also describes that the distributing head can adjust the thickness of the dispensing material while traveling. However, since the discharging aperture of the distributing head is fixed, the purpose of distributing materials with different thicknesses can only be achieved by adjusting the feeding speed or the moving speed of the distributing head. Therefore, its forming speed is not faster than the original method of horizontally stacking fabrics and connecting dots into lines for solidification. In addition, U.S. Patent Application Publication No. 2015/0266244 A1 also describes the use of a distributing head to move in a curve in space and adjust the material extrusion flow rate to control the thickness of the dispensing material, but it also uses a fixed discharge aperture. Generally speaking, the discharge hole diameter of the FDM cloth head is about 0.25 to 1mm (see www.matterhackers.com/news/3d-printer-nozzle-comparison-guide). The diameter of the linear material extruded by the cloth head is roughly the same as the discharge hole diameter. The range in which the diameter of the linear material can be changed by adjusting the material extrusion flow rate is also very limited.

In another FDM-related technology, U.S. Patent No. 8221669 discloses that when strip-shaped (non-cylindrical) raw materials are used as the supply material, the response time is shorter than the cylindrical raw materials used in current commercial systems. , where "response time" is the delay time required to start or stop the actual flow rate change at the end of the extrusion tip of the liquefier when the supply mechanism receives a command to supply/pause raw materials to the liquefier. This patent improves the aesthetics and structural quality of parts by reducing response time. However, how to increase the stacking deposition rate of materials is not the purpose of this patent and is not mentioned in this patent.

There are also other rapid prototyping methods for making metal parts. For example, the U.S. Patent U.S. 7942987 discloses the concept of using the FDM method to construct metal parts. This patent describes a method of heating a metal alloy to between the solidus temperature and the liquidus temperature, so that the metal alloy is in a semi-solid state and has sufficient viscosity. , to facilitate extrusion forming. However, this is basically a point scanning and horizontal lamination forming mode.

Another method is collectively called Laser Deposition Technology (LDS). US Pat. No. 4,323,756 discloses the technical concept of using wires and using energy beams as heat sources to melt and deposit them on the surface of objects. In order to reduce the installation of powder silos and simplify subsequent processing, US Patent No. 5043548 discloses the use of airflow to carry fine powder into a laser beam to melt and deposit on the object, where the laser beam is not directly focused. On the object, it will not cause the object to melt. The laser beam is focused on the position where the powder is fed to melt the powder and spread it on the object. This is basically still a point scanning forming mode, and the edge contour of the formed object is also relatively rough.

There is also research into using cloth outlets that can change in size to speed up the molding speed. For example, Brooks et al. designed an extrusion head with a two-stage opening, which can be adjusted to select thicker or thinner extrusion material wire diameters, and the range of change is also limited. However, its forming is still done layer by layer, which cannot solve the problem of lamination steps. [4 H.Brooks et al., "Variable fused deposition modeling-concept design and tool path generation", in Rapid Design, Prototyping and Manufacturing , pp.113-122.ISBN 978-0-9566643-1-0, from eprints .lancs.ac.uk/50959/]

U.S. Patent No. 6030119 describes a cloth device that can change the length of the outlet opening. The opening mechanism uses two planar components to overlap to form a long opening. The opening can be adjusted by adjusting the relative positions of the two components. length. However, it is still formed layer by layer, and there is still the problem of stacking steps. In addition, the purpose is to speed up the forming speed, so the length of the maximum opening is very wide. Therefore, the cloth device only moves along a single axis during each layer of cloth, and it is not suitable for multi-degree of freedom movement.

The previous invention of one of the inventors in this case (Republic of China Patent No. I611909 and U.S. Patent No. Patent No. 10,766,802 B2) describes an "elastic changeable cloth" 3D forming technology. The basic principle is to use a cloth head to coat a fluid curable material on a base so that it can function under certain environmental conditions. It becomes a solid state, and causes the cloth head to move relative to the base in space according to a predetermined cloth path, causing the curable material to be continuously coated, and the front and rear materials to be cured and connected in sequence at a predetermined position to form a 3D part. . The distribution path is not limited to the current horizontal lamination mode. It adopts a forming strategy that flexibly changes the lamination direction according to the needs of the geometric shape of the part. When good surface quality is required, the material is layered along the tangent direction of the surface of the 3D part. Forming, so it can eliminate the contour step problem caused by the horizontal lamination method, making the formed surface of the part smooth. This technology uses a kinematic mechanism device with multiple independent degrees of freedom to enable the cloth system to produce a 3D curve trajectory in space on the base. When distributing materials, the thickness, width, and speed of the discharging material can be adjusted according to the local geometry of the part, and geometric shapes including strips, lines, points, etc. can be produced. When the geometry of the 3D part is appropriate, increase the The width of the material is used to form a surface with lines, and the area-based cloth method makes the cloth appear in a strip shape, which greatly speeds up the forming speed, while geometric shapes such as lines and points are used for the finer feature structures of 3D parts. In addition, when distributing materials, a micro-forming mechanism is partially added to the surface of the material in the area where the curing process occurs to limit the flow of the curing material, allow it to solidify into the desired shape, and produce good surface smoothness; Furthermore, the curvature of the strip-shaped discharge material can be changed in the width direction to match the local geometry of the part.

Figure 2 takes the shape of the part in Figure 1(a) as an example to illustrate the forming steps of the above-mentioned "elastically changeable fabric" method. This figure assumes that the cloth head 401 moves and the base 501a does not move. (a)-(c): The cloth head coats the strip-shaped discharge material on the carrier, and multiple layers of strip-shaped discharge materials are superimposed (that is, the two strip-shaped discharge materials are connected to each other with a wide surface) to form the inside of the wheel hub. (d)-(e): Paving the outside of the wheel hub. (f) Make the blade base 603 as the starting point for forming the next blade. (g) Blade forming: The blades are formed by multiple strips of strips of material connected side by side with narrow surfaces (this is called stitching). The first strip of blade material is the blade edge 601. When forming, it is first joined to the base 603, and then the material is applied outward. At certain intervals, the supporting posts 605 are connected to the prefabricated bracket 610, and finally the material is joined. Based on the prefabricated support frame configuration 430. Subsequently, the second strip of strip 602 of the blade is also first joined to the base 603, and then uses the The cured edge portion 601 serves as a support and is connected side by side with the edge portion 601 by sewing. Another option is to first build the support structure under the blade, such as the current FDM method or SLA method. Also note that the width of the strip shown in the figure can be changed, so it can be sewn into the outline of the entire blade.

In order for the cloth system to generate any 3D curve trajectory as shown in Figure 2 on a base in space, multiple independent degrees of freedom are required. Under normal circumstances, if the material outlet of the cloth head is only a single hole, it means that the degree of freedom of the motion device must be at least 3 to allow path tracking of 3D curve trajectories. However, if a wide strip of material is to be coated, the motion device must have at least 4 independent degrees of freedom.

Figure 2(h) shows an example of the machine structure used in the above-mentioned "elastically changeable fabric" technology. Its basic structure is a 5-degree-of-freedom (5-axis) machine with 3 linear motion degrees of freedom (X, Y, Z) and two degrees of freedom of rotational movement (A-axis (rotates around the X-axis), B-axis (rotates around the Y-axis)). The base area 501 such as the workpiece and its carrier is placed on the A-axis rotary table. The cloth system 401 is mounted on the Z-axis, and the cloth head can rotate around the Z-axis, which is the sixth degree of freedom (C-axis).

The above-mentioned Republic of China Patent No. I611909 (and US Patent 10,766,802 B2) proposes a new 3D forming concept and corresponding implementation methods to address the shortcomings in the basic methods of other current major additive manufacturing technologies. However, the fabric system of this technology only uses one fabric outlet and only one discharging direction. In the process of changing the direction of fabric forming, it is often necessary to change the distribution direction of the fabric outlet and the relative seating direction of the 3D part. This is adjusted by a multi-degree-of-freedom motion mechanism device. When the relative orientation changes greatly, the motion of the motion mechanism device will change more drastically, or more degrees of freedom will be required. This will cause inconvenience in motion path planning and may increase the hardware cost of the motion mechanism device. As shown in Figure 2, the x-y-z coordinate system is used to illustrate the seating direction of the cloth head 401. It can be seen that the seating direction of the cloth head relative to the workpiece (or base 501a) changes greatly during the molding process. The multi-degree-of-freedom motion mechanism device Each degree of freedom must have a large range of motion. As shown in Figure 2(a) to Figure 2(d), the cloth head must be almost at a right angle around the y-axis so that the discharge port is close to the outer side wall of the hub. As shown in Figure 2(f) when making the blade base, since it is necessary to adopt a vertical discharging method (that is, the discharging height is greater than the width, such as a low wall shape), not only does the cloth head need to be tilted around the x-axis, but it must also be tilted sideways around the x-axis. Only when the cloth head rotates at a larger angle around the y-axis can the material be discharged vertically.

In order to solve the above problems, one aspect of the present invention proposes a system for manufacturing 3D objects, which includes: an anisotropic dual-outlet distribution head for coating a material to manufacture a 3D object. The anisotropic dual-outlet distribution head includes Two cloth outlets with different distribution directions can independently discharge materials in two different directions; a material supply unit is used to supply materials to the dual outlet cloth heads in different directions; a base is used to carry coating materials and 3D Object; and a movement mechanism device for causing the cloth head to produce a relative movement to the base in space according to a predetermined trajectory.

According to an embodiment of the present invention, the distributing head with dual outlets in opposite directions further includes a material chamber, wherein the two distributing outlets of the distributing head with dual outlets in opposite directions are connected to the material cavity in the distributing head with double outlets in opposite directions. chamber, the material supply unit supplies materials to the material chamber, and can adjust the feeding rate to match changes in the discharge flow rate. The two cloth outlets each include a gate mechanism that can continuously change the size of the outlet, and the two cloth outlets can be adjusted independently. The size of the cross-section of the cloth outlet is used to coat strip-shaped materials with different widths or continuously changing widths.

According to another embodiment of the present invention, one of the gate mechanisms further includes at least one gate element, and the gate element further includes a groove feature. When the gate element is completely closed, the groove feature and the counter-direction double outlet distribution head The wall forms a nozzle structure for coating linear and dot-shaped materials.

According to yet another embodiment of the present invention, the control direction of the gate mechanism includes the thickness direction and the width direction of the two cloth outlets, wherein a plurality of gate elements can be used in the width direction to push each other but operate independently to adjust the outlet opening. size.

According to another embodiment of the present invention, one of the two cloth outlets includes a horizontal discharge port, the long side of the opening of the horizontal discharge port is substantially parallel to the horizontal direction, and one of the gate mechanisms includes a Horizontal gate mechanism. The horizontal gate mechanism includes a horizontal gate element. The horizontal gate element is arranged approximately vertically in the material chamber. When the horizontal gate mechanism is opened and closed, the horizontal gate element rotates and moves in a movement mode that causes the lower end of the horizontal gate element to exit horizontally. The long side of the opening of the material port moves linearly and keeps the internal volume of the material chamber roughly constant, so as to adjust the size of the discharging section and maintain stable discharging.

According to another embodiment of the present invention, the horizontal gate element is a part of the structure constituting the material chamber. The horizontal gate mechanism includes: a U-shaped structure integrally connected with the horizontal gate element, and a two-link mechanism including a U-shaped Structure, one end of the two-link mechanism is fixed and can only rotate, and the movement of the other end is limited by a limit slot.

According to another embodiment of the present invention, it further includes a shaping device for trimming the coated and formed material and removing excess material; a movable tool table, a counter-direction double outlet distribution head and a shaping device are all installed on the On it, you can switch positions as needed to approach 3D objects for cloth or trimming work.

According to another embodiment of the present invention, the shaping device includes a hot scraping tool. The hot scraping tool contacts the coated and formed material to soften the excess material and then remove it.

According to another embodiment of the present invention, the hot scraping tool includes a curved member and an actuator. The actuator rotates the curved member to produce different curvatures when different parts of the curved member come into contact with the material.

According to another embodiment of the present invention, the hot scraping tool includes a deformable member and an actuator, and the actuator can adjust the curvature of the deformable member.

According to another embodiment of the present invention, the motion mechanism device has at least 4 degrees of freedom of movement.

Another aspect of the present invention provides a method for manufacturing 3D parts, which includes: A curable material that becomes fluid after being heated is used to accumulate the material layer by layer on a base to form a 3D product. The curable material can be cured at a predetermined temperature. When accumulating a layer of material, a motion mechanism device is first used. A cloth head causes relative movement to the base in space according to a predetermined cloth trajectory. At the same time, the cloth head coats the curable material into a thick layer, and then uses a shaping device to move the base in space according to a predetermined path. The shaping trajectory produces relative motion, trims the surface of the thick layer of material, removes excess material and improves surface smoothness, then accumulates the next layer of material, and repeats the above steps until the 3D part is completed. Thick layer refers to a layer of fabric that requires curvature and shape changes in the vertical direction within the thickness. The shaping device includes a hot scraping tool, and the process of trimming the thick layer includes the hot scraping tool moving according to a predetermined shaping trajectory and contacting the thick layer and at least another thick layer immediately below the thick layer, locally heating and softening the material, and then removing the predetermined For excess material beyond the shaping trajectory, the hot scraping tool contains a mechanism that can adjust the curvature shape of the contact surface with the material in the lamination direction, so that the side surface of the trimmed thick layer is correctly continuous and smooth in the lamination direction. shape.

103:Blade

102:wheel hub

140:Rotating axis

201: dotted line

203:Thick black curve

212,214: Surface roughness

217, 218: Horizontal stacking

401, 401M: cloth head

404H: Material cavity

404H1:Right wall

404H2: Left wall

404H3:Superstructure

404H31: Lower edge of upper structure

404H4: Horizontal gate element

404H41: Upper end of horizontal gate element

404H42: Lower end of horizontal gate element

404H43: Handlebar

404H43a: Horizontal part

404H5: Vertical gate element

404H5a, 404H5b, 404H5c: gate components

404H10: Material Chamber

404G20: Groove Features

405V, 405H: Discharge port

405G:Export

405Ha, 405Va: Long side of the discharge port

406: Material entrance

420A1: U-shaped thin plate

420A1a, 420A1b: Part of U-shaped thin plate

420A2, 420A3: Grip part

420A4: Pivot

430: Support frame configuration

451, 451a, 451b, 451c: Strip discharge

460:Substrate

461: L-shaped structure

462: straight column

463:shaft

463a:Axis

464:Limit slot

465:Trajectory

466, 468: rotating shaft

467: Crossbeam

501a: Base

505: Rotatable tool table

506:Tool table

506b: Movable platform

506a: Base

530: Plastic surgery device

531:Hot scraping tool

532:qubang

532a:Inner arc

532b, 532c: Left side of curve stick

533:Heater

534:Rotating device

540:Surface

545:Surface

546, 547: excess material

601: Edge

602: Strip discharging

603:Base

605:Support column

610: Bracket

712a, 712b: Strip discharge width

713a, 713b: Strip discharge height

1501, 1502: Direction

C1, C2, C3: Curve

O, P, P*, Q: points

S1, S2, S3: Surface

The features and advantages of the present invention can be further illustrated by the following drawings and corresponding detailed description:

Figure 1(a) is a schematic diagram of a 3D part. Figures 1(b) and 1(c) illustrate the situation of manufacturing the 3D part of Figure 1(a) using current additive manufacturing technology; Figures 2(a)-(g) Taking the product in Figure 1(a) as an example, a single outlet cloth head using the previous technology "elastically changeable fabric" technology is used to elastically change the direction of the fabric for forming; Figure 2(h) is a schematic diagram of the previous technology An example of the machine structure used in the "elastic direction-changing fabric" technology; Figure 3 shows the basic concept of the different-direction dual-outlet fabric head of the present invention and a schematic representation of the fabric situation; Figure 4 is a schematic diagram of using the product in Figure 1(a) as an example to use the counter-direction dual-outlet distributing head of the present invention to elastically change the direction of the fabric for forming; Figure 5 is the structure of the counter-directional dual-outlet distributing head of the present invention. One of the design examples and operation; Figure 6 is a design example of adjusting the size of the outlet opening of the distributing head in Figure 5; Figure 7 is a second design example of the structure and operation of the different-direction double-outlet distributing head of the present invention ; Figure 8 is another design example of adjusting the opening size of the discharging port of the distributing head of the present invention.

Figure 9 is another design example of adjusting the opening size of the discharging port of the distributing head of the present invention.

Figure 10(a) is an example of multi-layered vertical strip materials of the present invention being sewn into an object in the vertical direction; Figure 10(b) is an example of a shaping device of the present invention that modifies the surface of an object; Figure 11 is an example of machine equipment of the present invention. , including a movable tool table that can alternately perform the cloth head and the shaping device to modify the surface of the object; Figure 12 is a second example of the machine equipment of the present invention, including a movable tool table that can interactively perform the cloth head and the shaping device to modify the surface of the object; Figure 13 is another example of a movable tool table according to the present invention that can alternately use the cloth head and the shaping device to modify the surface of an object; Figure 14 is an example of a hot scraping tool of the shaping device according to the invention and its working principle.

Figure 15 is another example of the hot scraping tool of the shaping device of the present invention.

Figures 16(a)-(e) illustrate the principles and steps of the "thick layer forming" method of the present invention.

In order to solve the above problems, the present invention proposes a new non-directional double outlet cloth head. The material head contains two cloth outlets with different distribution directions. In particular, it contains two cloth outlets that are basically perpendicular to each other. One outlet can be used to coat in the horizontal direction to produce a horizontal strip discharge, and the other outlet can be used to coat in the vertical direction to produce a vertical strip. Discharge. The two cloth outlets can be connected to supply materials from the same material chamber. Figure 3(a) shows the basic concept of the opposite-direction double-outlet distributing head 401M. The counter-direction double outlet distributing head 401M includes a vertical outlet 405V and a horizontal outlet 405H. Figure 3(b) shows the situation of vertical strip discharging. Figure 3(c) shows the situation of horizontal strip discharging. Generally speaking, the cloth head used in the present invention includes a mechanism that can adjust the opening size of the cloth outlet. The ratio of the maximum opening area to the minimum opening area is at least about 10 to 200 times, so it can cope with different geometric feature sizes and increase Distribution rate (volume forming rate).

In addition, the present invention also includes a shaping device for shaping the surface of the cured material to modify the curvature of the surface and improve the surface smoothness. The different-direction double-outlet cloth head and shaping device are both installed on a movable tool table. The movable tool table is mounted on a multi-degree-of-freedom motion mechanism device. The positions of the cloth head and shaping device can be changed as needed to bring them closer to the machine. fabric or trim work on the piece. One example of the shaping device includes a cutting tool, and another example is a hot scraping tool.

Furthermore, the present invention also includes a "thick layer forming" method. In this method, a material with a larger thickness is first coated with a cloth head on each layer, and then a shaping device is used to trim the surface of the material. This is done alternately for each layer. Forming layer by layer can quickly produce objects with smooth curved surfaces.

Figure 4 takes the shape of the workpiece in Figure 1(a) as an example to illustrate the situation of elastically changing the direction of fabric forming by the different-direction dual-outlet cloth head of the present invention, and compares with Figure 2. As shown in Figure 4(a) to Figure 4(b), the horizontal discharge port is used to carry out horizontal strip discharging to make the inside of the wheel hub. As shown in Figure 4(a) to Figure 4(d), when making the outer side wall of the wheel hub, you can use the vertical outlet to dressing the side wall, so the cloth head only needs to be slightly tilted around the y-axis. As shown in Figure 2(f) when making the blade base, you only need to tilt the cloth head around the x-axis, and you can use the vertical outlet to discharge the material vertically.

The curable materials described in the present invention may include any material that has a fluid state and is in a specific environment. Materials that can be transformed into a solid state under environmental conditions.

For example, many polymeric materials have this property. Most thermoplastic polymer materials become fluid at high temperatures and solidify at low temperatures, such as nylon, PMMA, and PS (such as ABS). Wax is another material with such curable properties. Wax and thermoplastic polymer materials can be used to make patterns (patterns) for precision casting (such as lost wax casting).

Another type of curable material may be a paste material. Paste material is a mixed state of solid particles and liquid carrier. For example, in the traditional metal powder injection molding process, the metal powder is mixed in a fluid carrier of heated wax and polymer, injected into the mold together, and becomes a solid blank after cooling. The wax and polymer in the solid blank are then removed by chemical attack or combustion, and the remaining metal powder blank can be sintered and consolidated to increase its strength.

Another example of a pasty material is ceramic slurry. Ceramic slurry is a mixture of fine ceramic powder mixed with water and a binder. Ceramic slurry can be spread and formed in the manner described previously. If the porcelain slurry has high fluidity and low viscosity, it can be distributed by injection; if the porcelain slurry has low fluidity and high viscosity, it can be distributed by extrusion. More preferably, while the cloth is being clothed, hot air can be blown over the cloth to accelerate the drying process of the ceramic slurry, thus forming a ceramic powder blank. The ceramic powder blank can be consolidated by sintering.

Another example of a pasty material is concrete slurry to create cementitious components.

Another type of curable material can be glass. Glass can be melted by adjusting pressure and temperature, distributed by extrusion, and solidified into shape by controlling temperature.

Another form of the present invention is to coat a powdery material that can be combined and perform a bonding process on it, so that the powdery material can be consolidated into one body on the base. For example, metal or plastic powders are granular materials that can be bonded together. They can be bonded by local heating with laser or arc welding heat to melt part or all of the powder particles. When the material leaves the local heating area, the powder cools and solidifies. One body. Another example of a bonding process is to apply powder spray adhesive to another pair to consolidate them into one piece. For example, the added binder used in traditional processes such as metal powder injection molding or ceramic powder molding can be used to consolidate metal powder or ceramic powder.

The device that implements the forming includes a kinematic mechanism device with multiple independent degrees of freedom, which allows the cloth system to produce a 3D curve trajectory on the base in space. It also includes a discharging cloth head, which can also include a differential forming mechanism. In addition, It includes a feeding system that can adjust the feeding speed and an environmental control system that can regulate environmental conditions. In terms of process and software programs, it includes the previously mentioned forming program, the program for decomposing and reorganizing geometric data, the program for generating forming parameters and process parameters, the program for controlling the movements of the cloth head and differential forming mechanism, and the program for controlling the machine to generate 3D Program for curve trajectories. The following describes the specific implementation of the device and the corresponding operation method.

Example: Distribution head with two discharging directions and adjustable discharging opening size

In the prior art, a cloth head only had one discharging opening, and the opening had only one discharging direction. By adjusting the seat direction of the cloth head itself, the angle and attitude of the cloth outlet relative to the base or machine table can be changed, so that horizontal (horizontal) strip materials or vertical (vertical) strips can be coated. shape material. Being able to fabric in both horizontal and vertical directions helps to increase the operational flexibility of fabric forming, because strips of material at different angles can be quickly assembled into a 3D object, as shown in the example in Figure 2. If the cloth head can produce horizontal or vertical strip materials without adjusting its own seating direction, it can reduce the degree of freedom required on the machine, simplify the machine operation, and increase the geometric combination of fabrics into 3D objects. elasticity.

The different-direction dual-outlet distribution head of the present invention includes two distribution outlets that are connected to the same material cavity, but the long sides of the discharge opening are approximately perpendicular to each other. One outlet can be used to produce horizontal coating in the horizontal direction. For strip discharging, the other outlet can be used to coat in the vertical direction to produce vertical strip discharging. The two cloth outlets are controlled and opened by independent gate mechanisms.

Figure 5 shows an example of the structure and operation of the opposite-direction double-outlet cloth head. As shown in Figure 5(a), the material cavity 404H includes two side walls (right wall 404H1 and left wall 404H2), two gate elements (horizontal gate element 404H4 and vertical gate element 404H5) and a gate element sandwiched between the two side walls. The superstructure of 404H3. The space bounded by the two side walls, the two gate elements and the superstructure is the material chamber 404H10, the upper opening is an inlet 406 for the material supply unit (not shown) to feed materials. The material supply unit supplies material to the material chamber and can adjust the supply rate to match changes in the discharge flow rate. The gate mechanism includes a horizontal gate element and a vertical gate element. The horizontal gate element 404H4 controls the outlet with one long side in the horizontal direction, and the vertical gate element 404H5 controls the outlet with one long side in the vertical direction. Figure 5(a) shows the situation when both gates are closed. As shown in Figures 5(b) and 5(c), when the horizontal gate element 404H4 moves and rotates counterclockwise, the horizontal discharge port 405H is opened. The long side 405Ha of the horizontal discharge port is in the horizontal direction. When the horizontal gate element moves to different positions, the coated strip-shaped discharge material 451 will have different widths in the horizontal direction, as shown at 712a and 712b in Figures 5(b) and 5(c). As shown in Figures 5(d) and 5(e), when the vertical gate element 404H5 moves upward, the vertical outlet 405V is opened. The long side 405Va of the vertical outlet is vertically oriented. Similarly, when the vertical gate element moves to different positions, the coated strip discharge material 451 assumes the shape of a vertical low wall and presents different heights in the vertical direction, as shown in Figures 5(d) and 5(e), 713a and 713a. 713b is shown in two places.

As shown in the example of Figure 5, the vertical and horizontal discharge ports are connected and lead to the same material chamber 404H10. The two gate components independently control the opening and closing of the two discharge ports. The two gates can also be opened at the same time to coat a strip of material, as shown in Figure 5(f). Figure 5(f) shows that the cloth head is applying a section of vertical strip material 451b to the upper edge of another section of vertical strip material for vertical stitching. In this case, opening the horizontal outlet at the same time while fabricating can increase the contact area and help stitch the upper and lower strip materials.

When the material cavity 404H is assembled, screws and additional locking structures (not shown) are used to maintain appropriate clearance between the two side walls and the two gate elements, as well as between the upper end 404H41 of the horizontal gate element and the lower edge 404H31 of the upper structure 404H3. The contact pressure makes the leakage of the fluid material in the cavity from the contact surface very small, but at the same time allows the two gate elements to move.

The horizontal gate element is opened and closed in a rotational manner instead of horizontal linear movement, which can significantly reduce the length of the lower end of the material cavity. As shown in Figure 5(c), the horizontal gate element 404H4 is fully open. The length of the lower end of the material cavity is only a little longer than the length of the horizontal discharge port 405H. This can reduce the chance of collision between the cloth head and the formed object. Ideally, when the horizontal gate element is opened and closed, its lower end 404H42 should move linearly along the long side 405Ha of the horizontal outlet. However, if the horizontal gate element rotates around a fixed axis, its lower end 404H42 will definitely move in an arc shape. Therefore, the horizontal gate element should adopt a rotation and translation movement method.

Figure 6 shows a horizontal gate switching mechanism that can achieve the above ideal movement method. First, since the distance between the two side walls is very small, the mechanism for driving the two gates is placed outside the two side walls (outside the right wall 404H1). The horizontal gate component 404H4 has a handle portion 404H43 that is integrated with the straight column 462 outside the right wall 404H1 via an L-shaped structure 461. The handle part 404H43, the L-shaped structure 461 and the straight column 462 form a U-shaped structure, and the right wall 404H1 is located in the U-shaped structure. The movement of the horizontal gate element 404H4 is close to the inner surface of the right wall 404H1. Since the above-mentioned U-shaped structure is an integrated structure, moving the straight column 462 on a plane parallel to the right wall can drive the horizontal gate element to produce exactly the same movement. Therefore, the driving mechanism can be placed outside the side wall to drive the vertical column 462, thereby controlling the opening and closing of the horizontal gate.

The lower end 462 of the straight column 462 is connected to one end of a cross beam 467 through a rotating shaft 466, and the other end of the cross beam 467 is connected to a rotating shaft 468, and the rotating shaft 468 is fixed on a base plate 460. The upper end of the straight column 462 is connected to a shaft 463, and the shaft 463 is located in the curved limiting groove 464 on the base plate 460. That is, the straight column 462 and the cross beam 467 form a two-bar linkage mechanism, the rotating shaft 468 at one end is fixed on the base plate, and the shaft 463 at the other end is in the limiting groove 464. The base plate 460 is parallel to the right wall 404H1, and both are fixed on the cloth head. The limiting groove 464 limits the trajectory of the shaft 463 on the substrate to 465. The curve shape of the trajectory 465 is the same as the curve shape of the lower edge 404H31 of the upper structure 404H3 in the material cavity, and the two are aligned. The axis 463a of the shaft 463 is aligned with the upper end 404H41 of the horizontal gate element. Therefore, when pushing and pulling the shaft 463, under the restriction of the limiting groove 464, the upper end 404H41 of the horizontal gate element will be close to and move along the lower edge 404H31 of the upper structure 404H3. At the same time, based on the action of the 2-link mechanism (straight column 462 and cross beam 467), each different position of the shaft 463 on the limit groove track 465 will correspond to a different angle of the horizontal gate element. That is to say, there are different outlet opening sizes, and these positions and angles are kinematically determined. Finally, the curve shape of the lower edge 404H31 of the upper structure (and the limit groove track 465) is appropriately designed so that when the horizontal gate element is rotated and opened, its position will rise slightly at the same time, so that its lower end 404H42 can be along the long side 405Ha of the discharge port. Movement in a straight line.

In addition, when the horizontal gate element rotates and switches, the internal volume (volume) of the material chamber 404H10 should be kept roughly constant to avoid extrusion of material when the door is closed or internal cavitation caused when the door is opened, which will affect the discharge flow rate. control. For example, if the distance between the axis 463 and the rotating axis 466 is appropriately proportioned to the entire length of the horizontal gate element (upper end 404H41 to lower end 404H42), the internal volume of the material chamber can be kept approximately constant.

Figure 7 shows the structure and operation example 2 of the opposite-direction double-outlet cloth head. The difference between this example and the example in Figure 5 lies in the structure and operation mode of the horizontal gate. The horizontal gate element 404H4 of Figure 7 has a horizontal portion 404H43a near the lower end, which is located between the lower edges of the right wall 404H1 and the left wall 404H2. When the horizontal gate element 404H4 moves in the horizontal direction (x direction), the horizontal gate can be opened and closed. Figure 7(a) shows the situation when the horizontal gate is closed, and Figure 7(b) shows the situation when the horizontal gate is nearly fully open.

The examples in Figures 5 and 7 use a single gate component in the vertical direction, so that the height of the vertical discharge can be adjusted, but the width of the vertical discharge is roughly fixed. If multiple stacked but independently sliding gate elements are used, the width of the discharge can be adjusted. Figure 8 shows a design example of adjusting the size of the outlet opening. Compared with Figure 5, the vertical gate in this example uses multiple stacked but independently sliding gate components (404H5a, 404H5b, 404H5c). Independently adjusting the position of each gate element can adjust the discharge opening to produce several different discharge widths. As shown in Figure 8, a gate element can change the cross-sectional area of the discharge port opening several times from closing to opening. For example, if the opening width is 1mm and the maximum opening length is 5mm, the opening cross-sectional area can change from at least 1mm ² to 5mm ² . Using 3 independently sliding gate elements, the opening cross-sectional area can vary from at least 1 mm ² to 15 mm ² . The same principle can also be used for horizontal gates, using multiple horizontal gate elements that are stacked but can slide independently to adjust the thickness of the horizontal discharge.

Figure 9 shows another design example of adjusting the size of the outlet opening to coat linear materials. Figure 9 shows an enlarged view of the front end of the cloth head. The front end (lower end) 404H42 of the horizontal gate element 404H4 has a groove feature 404G20 on the upper edge of the portion of the left wall 404H2. When the horizontal gate element 404H4 and the vertical gate element 404H5 are fully closed, this groove feature forms a nozzle (or extrusion hole) structure with the inner wall of the left wall 404H2, and the material can be drawn from the material chamber 404H10 using this groove feature. The runner flows to outlet 405G and is extruded into linear material. At this time, it is basically the same as the current FDM method. Therefore, the flexibility provided by this technology includes the current FDM method. Assuming that the inner diameter of the groove feature 404G20 is 0.25mm (which is equivalent to the inner diameter of the nozzle of general FDM technology), and the opening size is 2mm wide and 5mm long when the discharge port is fully opened, the maximum change in the cross-sectional area of the discharge port opening can be 200:1.

In addition, although the angles of the two discharge openings in the example in Figure 5 are arranged in vertical and horizontal directions, they do not necessarily have to be perpendicular to each other in practice. It can still be achieved that the cloth head does not need to adjust its seating direction to produce horizontal or horizontal distribution. Vertical strip material purpose.

Example: Hot scraping and shaping device and "thick layer forming" method

When multiple strips are stacked or sewn together, there will inevitably be seam marks between the strips, which will affect the surface smoothness. Material expansion or contraction can also affect dimensional accuracy. For example, Figure 10(a) shows three vertical strip-shaped discharge materials (451a, 451b, 451c) sewn in the vertical direction into a strip-shaped discharge material 451. This can be produced by using a multi-degree-of-freedom machine as shown in Figure 2(h) to carry a distributing head to discharge material vertically to the discharge port. However, since the edge of the cloth outlet of the cloth heads of Figures 5 and 7 is straight, the surface of each strip of discharge material is also straight in the vertical direction, as indicated by 545. Therefore, in the vertical direction, the stitched surface is polyhedral rather than a true curve as shown by dashed line 540. To obtain the true curved surface as shown by the dotted line 540, it is necessary to remove the excess material as indicated by 546 and the excess material on the seam traces as indicated by 547.

To remove excess material, a shaping device can be used to perform secondary trimming on the fabric-shaped material. Since the fabric forming process of the present invention uses a multi-degree-of-freedom machine to generate multi-degree relative motion between the fabric head and the workpiece (the object to be formed), replacing the fabric head with a shaping device will allow easy access and trimming Most of the surface of the workpiece. One ideal approach would be to use a tool-changing tool holding system, like those used on CNC machine tools. Another approach is to use a movable tool table to carry the shaping device and the cloth head, and move the shaping device or cloth head close to the workpiece as necessary.

Figure 11 shows an example of a movable tool table, using a rotatable tool table 505. The shaping device 530 and the cloth head 401 are respectively installed at different positions on the rotatable tool table. The rotatable tool table is rotated as necessary to bring the shaping device or the cloth head close to the workpiece. As shown in Figure 11, the 5-degree-of-freedom machine of Figure 2(h) is used, and a rotatable tool table 505 is installed on the Z-axis moving platform. Figure 11(a) shows the use of the cloth head, and (b) shows the use of shaping. When installing.

And if a robotic arm-type multi-degree-of-freedom motion system is used, the shaping device 530 can be installed on the end of the cloth head, and then the closest rotating joint (such as the B-axis) is used for rotation transformation, as shown in Figure 12 shown.

Figure 13 shows another example of a movable tool table. A tool table 506 with linear displacement capability can be used to replace the rotatable tool table 505 in Figure 11. The tool table 506 includes an X2-axis movable platform 506b, which can be linearly displaced on its base 506a. The base 506a is installed on the Z-axis moving platform, and the shaping device 530 and the cloth head 401 are installed on the movable platform 506b at a certain distance. In this way, both the shaping device 530 and the cloth head 401 can move on the x-z plane as needed. Bring the shaping device or cloth head close to the workpiece respectively. Naturally, this linear displacement tool table can also be installed on the front end of a multi-degree-of-freedom robotic arm to switch fabrics or perform trimming work as needed.

For most materials, cutting tools can be used as shaping devices. For example, using a rotating milling cutter, especially a ball-end milling cutter, can be used with a multi-degree-of-freedom motion system (machine), Trace and cut surfaces of various shapes.

For materials with lower melting points (such as thermoplastics or waxes), a heating tool can be used as a shaping device to trim the formed material or improve its surface smoothness by hot scraping. This process is similar to cutting, but the hot scraping tool does not need to continuously rotate at high speed, and the material surface is easier to deform and trim after being heated.

The simplest hot scraping tool can be a straight cylindrical rod that can be heated. However, if you are trimming a curved surface and want to reduce the total number of scraping strokes, the scraping tool needs to be able to match the surface curvature at different locations on the workpiece surface to increase the contact width for each scrape. Figure 14 shows an example of a hot scraping tool that can be adjusted and adapted to different curved surfaces. Its working principle is to use a curved component. Rotating the curved component allows different parts of the curved component to come into contact with the coated material to produce different curvatures to meet the requirements. Required curvature change. The hot scraping tool 531 includes a bent rod 532, a heater 533 connected to the bent rod, and a rotating device (ie, "actuator") 534. The heater heats the bent rod to turn it into a hot scraper. The rotating device allows the heater and the bent rod to rotate integrally around the rotating shaft 140 . Further explanation below.

Figure 14(a) shows a side perspective view of the hot scraping tool. The curved rod is bent from the end point O to the upper starting point P. Point P is projected downward in a direction parallel to the rotating axis 140 to the horizontal plane where point O is located. P*point. Marking point Q marks the direction pointed by the outer arc surface of the curved rod for convenience of explanation. In Figure 14(a), the outer arc of the curved rod points directly to the right, so point P* is directly to the left of point O. S1 represents a curved surface facing and convex to the right. Under this relative seating relationship, when using a hot scraping tool to hot scrape the S1 curved surface, the contact curve between the curved rod 532 and the S1 curved surface is as C1, and its curvature is exactly the same as the inner circle of the curved rod seen from the side view in Figure 14(a) Arc 532a has the same curvature. Therefore, at this time, the same curvature as the curved rod itself from point O to point P can be hotly scraped.

Figure 14(b) shows another curved surface S2 that faces and protrudes to the right. The curvature (degree of curvature) of this curved surface is smaller than that of S1. At this time, the hot scraping tool can be rotated, as shown in the figure marked point Q (and Point P*) indicates that the hot scraping tool rotates an angle clockwise. The curvature of the left side 532b of the curved rod seen from the perspective of Figure 14(b) becomes smaller, so at this time, the curved surface S2 can be hot-scraped to produce a curved surface with a smaller curvature. Under this relative seating relationship, the contact curve between the curved rod 532 and the S2 curved surface, such as C2, extends obliquely on the S2 curved surface.

Figure 14(c) shows how to hot scrape a curved surface S3. At this time, the hot scraping tool can be rotated 90 degrees from the position in Figure 14(a), as shown by the marked point Q in the figure. From this perspective, the bend of the curved rod itself from point O to point P is no longer visible, and the curvature of the left side 532c of the curved rod becomes zero (and a straight line), so the curved surface S3 can be hot scraped. Under this relative seating relationship, the contact curve between the curved rod 532 and the curved surface S3, such as C3, shows the curvature of the curved rod itself from point O to point P on the curved surface S3.

Figure 14(d) and Figure 14(e) show how to heat scrape a concave surface to the right. The situation is similar to Figure 14(b) and Figure 14(a), except that the concave and convex are opposite and the angle of the hot scraping tool is different. I won’t go into details here.

Figure 15 shows another example of a hot scraping tool that can be adjusted and adapted to different curved surfaces. Its working principle is to use a deformable component and an actuator to change the curvature of the component. The hot scraping tool is mainly composed of two upper and lower flexible thin plates (i.e., "deformable components"). The two flexible thin plates may be two parts (420A1a, 420A1b) of a single U-shaped thin plate 420A1, see Figure 15(a). The two holding parts (420A2, 420A3) respectively connect the two ends of the two flexible thin plates, and are connected by a pivot 420A4 (i.e., the "actuator"). As shown in Figure 15(b), when the two holding parts are opened in the 1501 direction, the two thin plates (420A1a, 420A1b) are bent inward to form a concave surface. As shown in Figure 15(c), when the two holding parts are close to each other in the direction 1502, the two thin plates (420A1a, 420A1b) will bend outward to form a convex surface. The curvature of the surfaces of the two thin plates can be controlled by adjusting the opening and closing of the two gripping parts. The opening and closing of the two holding parts may use an appropriate actuating device, such as two coaxial but oppositely rotating worm gears (not shown in the figure). The heating device can be added to the side of the holding portion (not shown in the figure).

Using the hot scraping tool described above, you can trim surfaces with different curvatures. The excess material that softens or melts after heating is scraped off the surface of the workpiece with a hot scraper tool, and can then be removed by cleaning with a sponge or cotton cloth. As shown in Figure 10(b), a hot scraping tool 531 in the form of a curved rod is trimming the third layer of material.

Using the above-mentioned shaping device, the present invention also includes a "thick layer forming" method. In this method, a cloth head is used to coat a thicker layer of material on each layer, and then the shaping device is used to trim the surface of the material. This is done for each layer. Interactively and layer by layer, objects with smooth curved surfaces can be quickly produced. The layer-by-layer fabrication method of this method is similar to the FDM method, but the thickness (height) of each layer is much larger, so the total number of layers is smaller and the forming speed is faster. The shaping device is used to modify the curvature and shape in the vertical direction within each layer. In the traditional FDM process, the layer thickness must be small to produce shape changes in the vertical direction (ie, the direction of stacking). However, using a shaping device can trim a greater thickness at one time to a certain extent, so thick layers can be used to speed up the forming rate. After the forming and trimming of one layer of fabric is completed, a new layer of material is coated on it, and then a shaping device is used to trim the surface of the new layer of material and the joints with the previous layer to remove excess material and smooth the surface. In this way, the upward forming is repeated layer by layer. During the process, except for the uppermost layer being formed, all the layers below it have been trimmed. The cloth head and shaping device only need to extend downward for about 1 to 2 layers at most, which reduces the cost. Opportunities to collide with completed parts.

Figure 16(a)-(f) illustrates the "thick layer forming" method by taking a three-layer strip-shaped discharge structure and using the hot scraping tool 531 as an example. First, the cloth head applies the first layer (451a) and the second layer (451b), as shown in Figure 34(a). Then, the hot scraping and shaping device trims the first and second layers, as shown in Figure 34(b). Then the cloth head applies the third layer, as shown in Figure 34(c). Then, the hot scraping and shaping device trims the third layer and the second layer, as shown in Figure 34(d). At this time, since the second layer has been trimmed in the previous trimming step, this step is mainly to scrape off the excess material of the third layer and the traces of the seams between the second and third layers. As previously explained in Figure 16, using a rotatable curved rod can adjust the curvature of its contact with the material surface, including convex and concave surfaces of different curvatures and flat surfaces. As shown in Figure 34(e), the other side of the curved rod is used to trim the concave surface of the three-layer curved surface structure.

The embodiments described above are only for illustrating the technical ideas and characteristics of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the patent scope of the present invention. That is to say, all equivalent changes or modifications made in accordance with the spirit disclosed in the present invention should still be covered by the patent scope of the present invention.

For example, the above embodiment is based on the production of parts or models of general sizes, so the opening size of the cloth opening is on the order of millimeters. However, if large parts or models need to be produced, the size of the aforementioned cloth opening and the groove feature on the gate element should naturally be enlarged.

As shown in Figure 14, the shape and size of the curved rod can also be adjusted according to the nature of the parts or models to be produced. As long as the rotation of a curved rod is used to produce the required different heat scraping curvatures, it should still be covered by the patent of the present invention. within the range.

Another example is the "thick layer forming" method. The so-called "thick layer" refers to a layer of fabric that needs to have curvature and shape changes in the vertical direction. This thickness can be called a thick layer, and a shaping device can be used to trim each layer. Curvature, shape within the layer. Therefore, the so-called "thick layer" is also relative to the size and shape of the product, rather than an absolute standard size.

401M: Cloth head

405V, 405H: Discharge port

451: Strip discharge

Claims (12)

A system for manufacturing 3D objects, including: an anisotropic dual-outlet cloth head for coating a material to manufacture a 3D object. The anisotropic dual-outlet cloth head includes two cloth outlets with different distribution directions and can be independently Materials are discharged in two different directions respectively; a material supply unit is used to supply the material to the opposite-direction double outlet distribution head; a base is used to carry the coating material and the 3D object; a motion mechanism device, It is used to make the opposite direction double outlet distribution head produce a relative movement to the base in space according to a predetermined trajectory; and a shaping device is used to trim the material after coating and forming, and remove the excess material. . The system for manufacturing 3D objects as described in claim 1, wherein the opposite-direction dual-outlet cloth head further includes a material chamber, wherein the two cloth outlets of the opposite-direction double-outlet cloth head are connected to each other. The material chamber in the double-outlet distributing head; the material supply unit supplies the material to the material chamber, and can adjust the supply rate to match changes in the discharge flow rate; the two distributing outlets respectively include A gate mechanism with a continuously changing material outlet size can independently adjust the cross-sectional size of the two cloth outlets to coat the material in a strip with different widths or with continuously changing widths. The system for manufacturing 3D objects as claimed in claim 2, wherein one of the gate mechanisms further includes at least one gate element, and the gate element further includes a groove feature, When the gate element is completely closed, the groove feature and the inner wall of the counter-directional dual-outlet distribution head form a nozzle structure for coating the material in linear and dot-like shapes. The system for manufacturing 3D objects as described in claim 2, wherein the control directions of the gate mechanisms include the thickness direction and the width direction of the two cloth outlets, wherein a plurality of gate elements can be used to push each other in the width direction but operate independently. , to adjust the size of the outlet. The system for manufacturing 3D objects as described in claim 2, wherein: one of the two cloth outlets includes a horizontal outlet, and the long side of the opening of the horizontal outlet is substantially parallel to the horizontal direction; the gate mechanisms One includes a horizontal gate mechanism. The horizontal gate mechanism includes a horizontal gate element. The horizontal gate element is arranged in a substantially vertical direction in the material chamber. When the horizontal gate mechanism is opened and closed, the horizontal gate element performs a rotation and movement mode. Make the lower end of the horizontal gate element linearly move along the long side of the opening of the horizontal discharge port, and keep the internal volume of the material chamber approximately constant to adjust the cross-sectional size of the discharged material and maintain stable discharge. The system for manufacturing 3D objects as described in claim 5, wherein: the horizontal gate element is part of the structure constituting the material chamber; the horizontal gate mechanism includes: a U-shaped structure integrated with the horizontal gate element ; And a two-bar linkage mechanism includes the U-shaped structure, one end of the two-bar linkage mechanism is fixed and can only rotate, and the movement of the other end is limited by a limiting groove. The system for manufacturing 3D objects as described in claim 1 further includes: a movable tool table, the opposite-direction double-outlet cloth head and the shaping device are both installed on On it, you can change the position as needed to approach the 3D object for cloth or trimming work. The system for manufacturing 3D objects according to claim 7, wherein the shaping device includes a hot scraping tool. The hot scraping tool contacts the coated and formed material to soften the excess material and then remove it. . The system for manufacturing 3D objects according to claim 8, wherein the hot scraping tool includes a bending member and an actuator, and the actuator rotates the bending member to produce different curvatures when different parts of it come into contact with the material. . The system for manufacturing 3D objects according to claim 8, wherein the hot scraping tool includes a deformable member and an actuator, and the actuator can adjust the curvature of the deformable member. The system for manufacturing 3D objects as described in claim 1, wherein the motion mechanism device has at least 4 degrees of freedom of motion. A method for manufacturing 3D objects, which uses the system for manufacturing 3D objects as described in any one of claims 1 to 11, which includes: using a curable material that becomes fluid after being heated on a base Accumulating material layer by layer to form a 3D product, the curable material can be cured at a predetermined temperature; and when accumulating a layer of material, a motion mechanism device is first used to move a cloth head to the base in space according to a predetermined direction The cloth trajectory generates relative movement, and at the same time, the cloth head coats the curable material into a thick layer, and then uses a shaping device to generate relative movement of the base in space according to a predetermined shaping trajectory to trim the thick layer of material. On the surface, remove excess material and improve surface smoothness, then accumulate the next layer of material, and repeat the above steps until the 3D part is completed; The thick layer refers to a layer of fabric that requires curvature and shape changes in the vertical direction within the thickness; wherein the shaping device includes a hot scraping tool, and the process of trimming the thick layer includes the hot scraping tool according to the predetermined The shaping trajectory moves and contacts the thick layer and at least another thick layer immediately below the thick layer, locally heats and softens the material, and then removes excess material outside the predetermined shaping trajectory. The hot scraping tool includes an adjustable The mechanism of the curvature shape of the contact surface in the lamination direction, so that the trimmed side surface of the thick layer has a correct, continuous and smooth shape in the lamination direction.