阅读说明：本技术 三维物体及其打印方法、打印装置 (Three-dimensional object, printing method thereof and printing device ) 是由 余嘉 于 2020-03-25 设计创作，主要内容包括：本申请提供一种三维物体及其打印方法、打印装置,其中,方法包括：根据切片层打印数据利用至少一种实体材料在实体结构区进行打印,并利用至少一种支撑材料在支撑结构区进行打印；固化至少部分所述实体结构区的实体材料和所述支撑结构区的支撑材料,形成层打印结果,其中,所述层打印结果的支撑结构区具有孔洞。本申请提供的三维物体,浸泡在水、水性溶液、或碱性溶液等液体中时液体通过孔洞进入到支撑结构的内部,从而加快支撑结构的溶解或溶胀速率,提高支撑结构的去除效率,降低处理成本。(The application provides a three-dimensional object and a printing method and a printing device thereof, wherein the method comprises the following steps: printing in the solid structure area by using at least one solid material according to the slice layer printing data, and printing in the support structure area by using at least one support material; curing at least part of the solid material of the solid structure region and the support material of the support structure region to form a layer printed result, wherein the support structure region of the layer printed result has holes. The application provides a three-dimensional object, liquid enters into bearing structure's inside through the hole when soaking in liquid such as water, aqueous solution, or alkaline solution to accelerate bearing structure's dissolution or swelling rate, improve bearing structure's efficiency of getting rid of, reduce treatment cost.)

1. A method of printing a three-dimensional object, the method comprising:

printing in the solid structure area by using at least one solid material according to the slice layer printing data, and printing in the support structure area by using at least one support material;

curing at least part of the solid material of the solid structure region and the support material of the support structure region to form a layer printed result, wherein the support structure region of the layer printed result has holes.

2. The printing method of claim 1, wherein the support material comprises thermally expandable microspheres.

3. The printing method of claim 2, wherein the thermally expandable microspheres comprise a shell and a working medium contained in the shell, the shell is elastic, and the working medium expands in volume when heated.

4. The printing method of claim 3, wherein the housing is made of a thermoplastic elastomer.

5. A printing method according to claim 3, wherein the working medium is heated to convert from a solid or liquid state to a gaseous state.

6. The printing method according to claim 3, wherein before the printing with at least one solid material on the solid structure area and with at least one support material on the support structure area according to the cut-layer printing data, the method further comprises:

heating the support material, or heating the solid material and the support material.

7. The printing method of claim 6, wherein the heated temperature is equal to or higher than a temperature at which the working medium is converted from a solid or liquid state to a gaseous state, and lower than a temperature at which the housing expands to a maximum volume.

8. The printing method of claim 2, wherein the thermally expandable microspheres comprise 1% to 6% of the total weight of the support material.

9. The printing method according to claim 2, wherein the diameter of the thermally expandable microspheres is 100nm to 50 μm.

10. The printing method of claim 2, wherein the thermally expandable microspheres are dispersed in the support material.

11. The printing method of any of claims 1-10, wherein the support material is at least one of a photocurable material, a phase-change wax material, or a hydrogel material.

12. The printing method of claim 11, wherein the photocurable material comprises thermally expandable microspheres, a photocurable host material, a non-curable water-miscible material, a photoinitiator, and an auxiliary agent.

13. The printing method of claim 12, wherein the photocurable host material is a (meth) acrylate-based compound and/or a (meth) acrylamide-based compound, the water-miscible material is a polyol, and the auxiliary agent includes at least one of a surfactant, a polymerization inhibitor, a dispersant, and a colorant.

14. The printing method according to claim 1, wherein before the printing with at least one solid material on the solid structure area and with at least one support material on the support structure area according to the cut-sheet layer printing data, the method further comprises:

carrying out slicing processing on the digital model of the object to be printed to obtain a plurality of slice layers and slice layer image data;

and generating slice layer printing data according to the slice layer image data, wherein the slice layer printing data comprises data whether each voxel in the support structure area needs ink-jet printing.

15. The printing method of claim 14, wherein said printing with at least one support material in a support structure area comprises:

inkjet printing with at least one support material at each voxel in a support structure region, wherein at least some of the voxels eject the support material.

16. The printing method of claim 1, wherein after said curing at least a portion of said solid material of said solid structure region and said support material of said support structure region to form a layer printed result, said method further comprises:

printing layer by layer based on printing data of a three-dimensional object to be printed and superposing the layer printing results to form the three-dimensional object, wherein the three-dimensional object comprises a solid structure and a supporting structure;

and removing the support structure by means of dissolution or swelling to obtain a solid structure of the three-dimensional object.

17. A printing apparatus for a three-dimensional object, the printing apparatus comprising:

the jetting mechanism is used for jetting printing materials onto the supporting platform to form a material layer, wherein the printing materials comprise solid materials and/or supporting materials;

the curing mechanism is used for curing the material layer to form a layer printing result;

a controller for controlling the jetting mechanism and the curing mechanism to perform layer-by-layer printing and superposing the layer printing results to form a three-dimensional object by using the printing method of the three-dimensional object according to any one of claims 1 to 16, wherein the three-dimensional object comprises a solid structure and a supporting structure with holes.

18. The printing apparatus of claim 17, further comprising:

the leveling mechanism is used for leveling the uncured material layer;

and the lifting mechanism is used for driving the supporting platform to descend by a distance of a specified layer thickness or driving the spraying mechanism to ascend by a distance of a specified layer thickness.

19. The printing apparatus of claim 17, further comprising:

a heating mechanism for heating the support material, or heating the support material and the solid material.

20. The printing apparatus of claim 17, further comprising:

and the cooling mechanism is used for cooling the three-dimensional object so as to accelerate the formation of the hole by the support structure of the three-dimensional object.

21. The printing apparatus of claim 17, wherein at least one of the solid material and the support material is a photocurable material and the curing mechanism is a photocurable mechanism.

22. The printing apparatus of claim 21, wherein the light curing mechanism is at least one of an ultraviolet lamp, an electromagnetic radiation device, an infrared radiation device, a visible light lamp, a xenon lamp, and a mercury lamp.

23. The printing device of claim 17, wherein at least one of the solid material and the support material is a phase change wax material or a hydrogel material and the solidification mechanism is a cooling device.

24. A printing device according to claim 23, wherein the cooling device is a fan or a refrigerator.

25. A three-dimensional object printed according to the method of any one of claims 1 to 16, comprising a solid structure and a support structure, wherein the support structure has a plurality of holes.

Technical Field

The invention relates to the technical field of 3D object forming, in particular to a three-dimensional object, a printing method and a printing device thereof.

Background

The three-dimensional forming technology is also called as rapid forming technology, rapid prototyping technology or additive manufacturing technology, the basic principle of the three-dimensional forming technology is to slice a 3D model based on slice software, a data processor converts slice data of the model into layer printing data, and a controller controls a printing device to print layer by layer according to the layer printing data and form a three-dimensional object in an overlapping mode.

When the object with the suspension structure is printed, the suspension part below the suspension structure needs to be printed with the support structure, so that the target object can be formed; after the target object is formed, the support structure needs to be removed from the target object without affecting the surface accuracy of the target object; therefore, the support structure needs to have sufficient mechanical strength to support the target object while facilitating removal from the target object.

The types of existing support materials can be classified according to the removal mode of the support structure: mechanically removed support materials, water-soluble support materials, water-swellable support materials, alkali-soluble support materials, and the like; wherein, the support material removed by mechanical force can damage the target object due to the impact effect of mechanical force during the support structure removing process, and the support structure in the fine hole structure is difficult to remove; wherein the water-soluble support material and the water-swellable support material have slow dissolution and swelling rates in water, respectively, and particularly the removal rate of the support structure is slow when the support structure is large in volume; wherein, during the process of removing the alkali-soluble support material, the alkali-soluble support material is quickly saturated along with the prolonging of time, the removal rate of the support structure is slow, and therefore, the alkali solution needs to be replaced frequently. Therefore, the existing support structure has low removal efficiency and high treatment cost.

Disclosure of Invention

The embodiment of the invention provides a three-dimensional object, a printing method and a printing device thereof, which can improve the removal efficiency of a support structure and reduce the processing cost.

In a first aspect, an embodiment of the present invention provides a method for printing a three-dimensional object, where the method includes:

printing in the solid structure area by using at least one solid material according to the slice layer printing data, and printing in the support structure area by using at least one support material; curing at least part of the solid material of the solid structure region and the support material of the support structure region to form a layer printed result, wherein the support structure region of the layer printed result has holes.

With reference to the first aspect, in one possible embodiment, the support material comprises thermally expandable microspheres.

With reference to the first aspect, in one possible embodiment, the thermally expandable microspheres include a shell and a working medium accommodated in the shell, the shell has elasticity, and the working medium expands in volume after being heated.

With reference to the first aspect, in a possible implementation manner, the material of the housing is a thermoplastic elastomer.

With reference to the first aspect, in a possible embodiment, the working medium is heated to transform from a solid state or a liquid state to a gaseous state.

With reference to the first aspect, in a possible implementation manner, before the printing on the solid structure area with the at least one solid material and the printing on the support structure area with the at least one support material according to the slice layer printing data, the method further includes: heating the support material, or heating the solid material and the support material.

In a possible embodiment in combination with the first aspect, the temperature of the heating is equal to or higher than the temperature at which the working medium is transformed from a solid or liquid state to a gaseous state and lower than the temperature at which the housing is expanded to a maximum volume.

With reference to the first aspect, in one possible embodiment, the thermally expandable microspheres account for 1% to 6% of the total weight of the support material.

In a possible embodiment in combination with the first aspect, the thermally expandable microspheres have a diameter of 100nm to 50 μm.

With reference to the first aspect, in one possible embodiment, the thermally expandable microspheres are dispersed in the support material.

With reference to the first aspect, in one possible embodiment, the support material is at least one of a light-cured material, a phase-change wax material, or a hydrogel material.

In one possible embodiment in combination with the first aspect, the photocurable material includes thermally expandable microspheres, a photocurable host material, a non-curable water-miscible material, a photoinitiator, and an auxiliary agent.

With reference to the first aspect, in one possible embodiment, the photocurable host material is a (meth) acrylate compound and/or a (meth) acrylamide compound, the water-miscible material is a polyol, and the auxiliary agent includes at least one of a surfactant, a polymerization inhibitor, a dispersant, and a colorant.

With reference to the first aspect, in a possible implementation manner, before the printing on the solid structure area with the at least one solid material and the printing on the support structure area with the at least one support material according to the slice layer printing data, the method further includes: carrying out slicing processing on the digital model of the object to be printed to obtain a plurality of slice layers and slice layer image data; and generating slice layer printing data according to the slice layer image data, wherein the slice layer printing data comprises data whether each voxel in the support structure area needs ink-jet printing.

With reference to the first aspect, in one possible implementation, the printing on the support structure area with at least one support material includes: inkjet printing with at least one support material at each voxel in a support structure region, wherein at least some of the voxels eject the support material.

With reference to the first aspect, in a possible implementation manner, after the curing at least part of the solid material of the solid structure region and the support material of the support structure region to form a layer printing result, the method further includes:

printing layer by layer based on printing data of a three-dimensional object to be printed and superposing the layer printing results to form the three-dimensional object, wherein the three-dimensional object comprises a solid structure and a supporting structure; and removing the support structure by means of dissolution or swelling to obtain a solid structure of the three-dimensional object.

In a second aspect, an embodiment of the present invention further provides a printing apparatus for a three-dimensional object, where the printing apparatus includes:

the jetting mechanism is used for jetting printing materials onto the supporting platform to form a material layer, wherein the printing materials comprise solid materials and/or supporting materials;

the curing mechanism is used for curing the material layer to form a layer printing result;

and the controller is used for controlling the jetting mechanism and the curing mechanism to print layer by using the printing method of the three-dimensional object and superposing the layer printing results to form the three-dimensional object, wherein the three-dimensional object comprises a solid structure and a supporting structure with holes.

With reference to the second aspect, in one possible implementation, the printing apparatus further includes:

the leveling mechanism is used for leveling the uncured material layer;

and the lifting mechanism is used for driving the supporting platform to descend by a distance of a specified layer thickness or driving the spraying mechanism to ascend by a distance of a specified layer thickness.

With reference to the second aspect, in one possible implementation, the printing apparatus further includes:

a heating mechanism for heating the support material, or heating the support material and the solid material.

With reference to the second aspect, in one possible implementation, the printing apparatus further includes:

and the cooling mechanism is used for cooling the three-dimensional object so as to accelerate the formation of the hole by the support structure of the three-dimensional object.

With reference to the second aspect, in one possible embodiment, at least one of the solid material and the supporting material is a light curing material, and the curing mechanism is a light curing mechanism.

In a possible embodiment, in combination with the second aspect, the photo-curing mechanism is at least one of an ultraviolet lamp, an electromagnetic radiation instrument, an infrared radiation instrument, a visible light lamp, a xenon lamp, and a mercury lamp.

With reference to the second aspect, in one possible embodiment, at least one of the solid material and the support material is a phase-change wax material or a hydrogel material, and the solidification mechanism is a cooling device.

In a possible embodiment, in combination with the second aspect, the cooling device is a fan or a refrigerator.

In a third aspect, an embodiment of the present invention further provides a three-dimensional object, where the three-dimensional object is formed by printing according to the above-mentioned printing method for a three-dimensional object, and the three-dimensional object includes a solid structure and a support structure, where the support structure has a plurality of holes.

According to the three-dimensional object and the printing method thereof, the holes are formed in the supporting structure area in the curing process, so that when the supporting structure is soaked in water, aqueous solution, alkaline solution or other liquid, the liquid enters the supporting structure through the formed holes, the dissolving or swelling rate of the supporting structure is increased, the removal rate of the supporting structure is increased, the post-treatment efficiency of the three-dimensional object is improved, and the post-treatment cost of the three-dimensional object is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive labor.

Fig. 1 is a schematic structural diagram of a three-dimensional object printing apparatus according to an embodiment of the present disclosure;

fig. 2 is a schematic front projection diagram of a partial structure of another three-dimensional object printing apparatus according to an embodiment of the present application;

FIG. 3 is a flow chart of a method for inkjet printing a three-dimensional object according to an embodiment of the present disclosure;

FIG. 4 is a schematic cross-sectional view of a slice layer of a three-dimensional object provided by an embodiment of the present application;

FIG. 5 is a schematic diagram illustrating a bitmap representation of a slice layer image of a three-dimensional object according to an embodiment of the present disclosure;

FIG. 6 is a schematic view showing the change of state of thermally expandable microspheres before and after heating in the example of the present application;

FIG. 7 is a cross-sectional view of a support structure formed in an embodiment of the present application;

fig. 8 is a flowchart of another inkjet printing method for a three-dimensional object according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

For better understanding of the technical solutions of the present invention, the following detailed descriptions of the embodiments of the present invention are provided with reference to the accompanying drawings.

It should be understood that the described embodiments are only some embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the examples of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be noted that, in the X-Y-Z coordinate system indicated in the drawings, in the non-rotational printing mode of the support platform relative to the print head, the X axis is parallel to the printing direction, the Y axis is perpendicular to the printing direction and is parallel to the slice layer, that is, the X-Y plane is parallel to the slice layer, and the Z axis is parallel to the stacking direction of the slice layer and is perpendicular to the X-Y plane.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a three-dimensional object printing apparatus according to an embodiment of the present application, and fig. 2 is a schematic partial structural orthographic projection diagram of another three-dimensional object printing apparatus according to an embodiment of the present application.

As shown in fig. 1, the printing apparatus includes a support platform 1, an ejection mechanism 2, a curing mechanism 3, a leveling mechanism 4, a moving mechanism 5, a lifting mechanism 6, and a controller 7. In this embodiment, the printing apparatus is an inkjet three-dimensional printer.

And the spraying mechanism 2 is used for spraying preset printing materials onto the supporting platform 1 to form a material layer. Wherein the printing material comprises a solid material and/or a support material. The ejection mechanism 2 has a plurality of single-pass printheads, or has at least one multi-pass printhead, or a combination of a single-pass printhead and a multi-pass printhead.

And the curing mechanism 3 is used for carrying out curing treatment on the material layer so as to form a layer printing result. The selection of the curing mechanism 3 in the present application is selected according to the kind of solid material and support material for inkjet printing.

In one embodiment, when at least one of the solid material and the supporting material is a photo-curing material (e.g., a photosensitive resin), the curing mechanism 3 is a photo-curing mechanism, and specifically, the photo-curing mechanism may be an ultraviolet lamp, an electromagnetic radiation instrument, an infrared radiation instrument, a visible light lamp, a xenon lamp, a mercury lamp, or the like. The ultraviolet curing technology is a technology in which a photoinitiator is added into a system with a special formula (referred to as a photocuring system), and after high-intensity ultraviolet light generated in an ultraviolet curing mechanism is absorbed, active free radicals or cations are generated, so that polymerization, crosslinking and grafting reactions are initiated, and a solid material and/or a support material are converted from a liquid state to a solid state within a certain time.

In other embodiments, at least one of the solid material and the support material is a phase-change wax material or a hydrogel material, and the solidifying mechanism 3 is a cooling device, which may be a fan, a refrigerator, or the like.

And the leveling mechanism 4 is used for leveling the uncured material layer and improving the forming precision of the three-dimensional object. In the present embodiment, the leveling mechanism 4 is a leveling roller.

The moving mechanism 5 includes a guide rail and a carriage (not shown) attached to the guide rail, and the injection mechanism 2, the curing mechanism 3, and the leveling mechanism 4 are attached to the carriage and are capable of moving in the X direction along the guide rail.

The lifting mechanism 6 is used for changing the relative distance between the support platform 1 and the injection mechanism 2. Specifically, the lifting mechanism may be configured to drive the print head to move in the Z direction during the inkjet printing process so as to change the Z-direction relative distance between the support platform 1 and the print head 2, or the lifting mechanism may be configured to drive the support platform 1 to move in the-Z direction so as to change the Z-direction relative distance between the support platform 1 and the print head 2 during the inkjet printing process, that is, the lifting mechanism 6 is configured to drive the support platform 1 to descend by a specified layer thickness, or drive the ejection mechanism 2 to ascend by a specified layer thickness.

And the controller 7 is used for controlling the supporting platform 1, the spraying mechanism 2, the leveling mechanism 4, the moving mechanism 5 and the lifting mechanism 6.

In the embodiment of the present application, a three-dimensional object printing process is described by taking the lifting mechanism 6 as an example to drive the support platform 1. As shown in fig. 1, the supporting platform 1 is supported by a lifting mechanism 6, and a controller 7 is in signal connection with the lifting mechanism 6, specifically, the controller 7 controls the lifting mechanism 6 to drive the supporting platform 1 to descend by a distance of a specified layer thickness during the inkjet printing process.

In the embodiment of the present application, a supporting platform 1 and a printing head 2 of a printing apparatus keep moving relatively in a horizontal direction, specifically, as shown in fig. 1, the printing head 2 makes linear motion in the horizontal direction relative to the supporting platform 1, for example, the supporting platform 1 is fixed in the horizontal direction, the printing head 2 makes scanning motion in an X direction to execute inkjet printing, and step-by-step in a Y direction to execute inkjet printing; or as shown in fig. 2, an orthographic projection diagram of a partial structure of another three-dimensional object printing apparatus according to the present application is that the printing head 2 makes a circular motion in a horizontal direction relative to the supporting platform 1, specifically, the printing head 2 makes a reciprocating motion in a radial direction along the guide rail, and the supporting platform 1 makes a uniform circular motion.

In the orthographic projection view of a part of the structure of another three-dimensional object printing device shown in fig. 2, the moving mechanism 5 comprises a guide rail and a carriage (not shown) mounted on the guide rail, the jetting mechanism 2 is mounted on the carriage and can move along the guide rail in the radial direction, the curing mechanism 3 is fixedly mounted on the guide rail, the leveling mechanism 4 is rotatably mounted on the guide rail, the curing mechanism 3 and the printing head 2 are arranged opposite to each other in the radial direction, and the leveling mechanism 4 is arranged in the other radial direction between the printing head 2 and the curing mechanism 3. In one embodiment, the leveling mechanism 4 is a leveling roller. In order to improve the leveling accuracy of the leveling roller 4, the leveling roller 4 shown in fig. 1 has a cylindrical shape, and the leveling roller 4 shown in fig. 2 has a truncated cone shape or a conical shape, and the diameter of the outer periphery of the supporting platform 1 decreases as the center of the supporting platform approaches.

Further, the printing apparatus comprises a material reservoir 8 connected to the ejection mechanism 2 via a conduit 9 for supplying the printhead with the solid material and the support material.

The printing apparatus further comprises a heating mechanism 11, the heating mechanism 11 is used for heating the solid material and/or the supporting material in the material storage container 8; heating means 11 may be placed inside the material storage vessel 8 for directly heating the solid material and/or support material, such as a heating tank with a serpentine heating tube. The heating mechanism 11 may be disposed outside the material storage container 8, and by heating the material storage container 8, the heated material storage container 8 transfers heat to the solid material and/or the supporting material stored inside, thereby achieving the purpose of heating the solid material and/or the supporting material. The heating means 11 can also be arranged on the conduit 9 or be designed integrally with the conduit 9, by means of which conduit 9 the printing material conveyed through the conduit is heated.

In one embodiment of the present application, further, the printing apparatus further comprises a cooling mechanism 12, such as the cooling mechanism 12 shown in fig. 1, for cooling the three-dimensional object formed by printing, for example, by reducing the ambient temperature in the forming chamber 13 by the cooling mechanism 12, and increasing the cooling rate of the support structure; the cooling mechanism 12 is selected from at least one of the cooling devices described above, such as a fan, an air conditioner, a refrigerator, and the like.

The printing device further comprises a data processing device 10, wherein the data processing device is used for slicing the digital model of the object to be printed to obtain a plurality of sliced layers and sliced layer image data; and generating slice layer printing data according to the slice layer image data, and transmitting the printing data to the controller 7. The data processing device 10 is, for example, a slicing software, and the slicing software slices and layers a digital model of a three-dimensional object in the Z direction during slicing to obtain a plurality of slice layers and layer image data.

As can be understood, during the printing process, the controller 7 controls the moving mechanism 5 to move the jetting mechanism 2 in the horizontal direction based on the printing data, controls the jetting mechanism 2 to jet the printing material onto the support platform 1 to form the material layer, controls the leveling mechanism 4 to level the material layer which is not solidified yet so as to ensure the dimensional accuracy of the material layer, and controls the solidifying mechanism 3 to solidify the material layer to form the layer printing result. And the controller 7 controls the lifting mechanism 6 to move in the vertical direction, controls the injection mechanism 2, the leveling mechanism 4 and the curing mechanism 3 to repeat the steps to print layer by layer and superposes the printing results of the layers to form the three-dimensional object.

The shape of the three-dimensional object to be printed in the present application is not limited, and the three-dimensional object printing method in the present application is clearly described in the specific embodiment of the present application by taking the three-dimensional object 20 shown in fig. 1 as an example. The three-dimensional object 20 includes a solid structure 21 and a supporting structure 22, wherein the solid structure 21 is a target object, and the target object may be a single solid material or a plurality of different solid materials, and the specific solid material is determined by the properties of the solid structure. Wherein, bearing structure 22 plays the effect of support and/or parcel target demand object in the printing process of target demand object, improves the printing precision of target demand object, and bearing structure 22 need remove around target demand object after target demand object prints and accomplishes.

Fig. 3 is a schematic flowchart of a printing method for a three-dimensional object according to an embodiment of the present application, and as shown in fig. 3, the method includes:

step S01, printing in the solid structure area by using at least one solid material according to the slice layer printing data, and printing in the support structure area by using at least one support material;

and step S02, solidifying at least part of the solid material of the solid structure area and the support material of the support structure area to form a layer printing result, wherein the support structure area of the layer printing result is provided with holes.

In the scheme, the holes are formed in the supporting structure area in the curing process, so that when the supporting structure is soaked in water, aqueous solution, alkaline solution or other liquid, the liquid enters the inside of the supporting structure through the formed holes, the dissolving or swelling speed of the supporting structure is increased, the removal speed of the supporting structure is increased, the post-treatment efficiency of the three-dimensional object is improved, and the post-treatment cost of the three-dimensional object is reduced.

Further, before step S01, the method further includes:

carrying out slicing processing on the digital model of the object to be printed to obtain a plurality of slice layers and slice layer image data;

and generating slice layer printing data according to the slice layer image data, wherein the slice layer printing data comprises data whether each voxel in the support structure area needs ink-jet printing.

As shown in fig. 1, a three-dimensional object 20 of the present application includes a solid structure 21 and a support structure 22, fig. 4 is a cut-away view of a three-dimensional object according to an embodiment of the present application, fig. 5 is a bitmap representation of a cut-away image of a three-dimensional object according to an embodiment of the present application, and as shown in fig. 4 and 5, a cut-away layer of the three-dimensional object 20 includes a layer solid structure L_M20And a layer support structure L_Z20。

The bitmap image of the slice layer is a dot matrix image comprising pixels (also called voxels in three-dimensional modeling) to be ink-jet printed, as shown in fig. 5, each cell representing a voxel, T_Z20Indicating the voxels, T, of the support structure region to be ink-jet printed_M20Representing voxels of the solid structure region that need to be ink-jet printed.

In step S01, the printing on the support structure area with at least one support material includes:

inkjet printing with at least one support material at each voxel in a support structure region, wherein at least some of the voxels eject the support material.

It is to be understood that in the present application, inkjet printing is required in each voxel of the support structure region, and the support material is ejected in at least some of the voxels, for example, depending on the support strength requirement of the support structure, an ink drop of the support material and an ink drop of the solid material may be ejected simultaneously in each voxel of the support structure region, or the support material may be ejected in some of the voxels of the support structure region, the solid material may be ejected in some of the voxels of the support structure region, or the support material may be ejected in each voxel of the support structure region. For the purpose of simple and clear description of the present disclosure, the present embodiment is described by taking the case of jetting the support material in each voxel of the support structure region.

The curing process in this embodiment may occur after the inkjet printing of the current sliced layer is completed, or during the inkjet printing process of the print head. The solid material and the support material in this embodiment may be respectively selected from at least one of a photosensitive resin material, a phase-change wax material, or a hydrogel material, and the specific kind is not limited, and the solid structure is not dissolved in the solution of the support structure when the support structure is removed.

The support material herein includes thermally expandable microspheres, and the thermally expandable microspheres are dispersed in the support material. Fig. 6 is a schematic diagram illustrating a state change of a thermally expandable microsphere provided in this embodiment before and after being heated, where the thermally expandable microsphere 30 includes a shell 31 and a working medium 32 contained in the shell 31, the shell 31 has elasticity, and the working medium 32 expands in volume after being heated.

In the present embodiment, the working medium 32 is in a solid or liquid state at room temperature. Specifically, the working medium 32 is heated to change from a solid or liquid state to a gaseous state, causing the pressure inside the housing to increase, causing the housing to expand as shown in fig. a. Moreover, the working medium 32 can be transformed from a gaseous state to a solid or liquid state after being cooled, so that the pressure inside the shell is reduced, and the shell shrinks as shown in fig. b.

The working medium 32 may be, for example, a sublimable substance such as solid carbon dioxide, or a low-boiling-point liquid hydrocarbon such as isobutane or isopentane. The shell may be a Thermoplastic Elastomer having elasticity, such as polyurethane-based Thermoplastic elastomers (TPU), polyolefin-based Thermoplastic elastomers (TPO), Thermoplastic vulcanizates (TPV), Polyamide-based Thermoplastic elastomers (PATE), and the like.

In one embodiment, the diameter of the thermally expandable microspheres is preferably selected from 100nm to 50 μm.

In this embodiment, taking an example that the support material is selected from a photosensitive resin material, an ultraviolet lamp is used to cure the support structure region, and since the support material irradiated by the ultraviolet lamp absorbs heat during the photocuring process, the thermal expansion microspheres expand when heated, the volume occupied by the expanded thermal expansion microspheres in the ink droplets increases, the temperature of the support structure where the thermal expansion microspheres are located decreases after the photocuring process is completed, the volume of the thermal expansion microspheres decreases, and holes are formed in the peripheral region of the thermal expansion microspheres in the support structure. Specifically, as shown in fig. 7, which is a cross-sectional view of the support structure formed in the embodiment of the present application, a hole 221 is formed in the support structure 22. The diameter of the holes is about 20 um-150 um.

The supporting structure formed in this embodiment includes the hole 221, and after the three-dimensional object 20 is printed, when the three-dimensional object is immersed in a liquid such as water, an aqueous solution, or an alkaline solution, the liquid enters the inside of the supporting structure through the formed hole 221, so that the dissolution or swelling rate of the supporting structure is increased, the removal rate of the supporting structure is increased, the post-processing efficiency of the three-dimensional object is improved, and the post-processing cost of the three-dimensional object is reduced.

As shown in fig. 8, which is a flowchart of another three-dimensional object inkjet printing method according to an embodiment of the present application, on the basis of the foregoing embodiment, the three-dimensional object inkjet printing method according to this embodiment further includes, before the foregoing step S01, a step S0:

s0, heating the supporting material, or heating the solid material and the supporting material.

In this embodiment, the support material and/or the solid material is heated before the support material and/or the solid material is subjected to inkjet printing, and the solid material and/or the support material placed in the material storage container 8 may be heated by a heating mechanism, or the printing material conveyed through the conduit may be heated by a heating mechanism provided in the conduit. Thereby reducing the viscosity of the material, reducing the transmission power of the material and improving the ink jet fluency of the printing head. The heating temperature is not higher than the heat-resistant temperature of the print head. In this embodiment, taking the supporting material as the photosensitive resin material as an example, the heating temperature is equal to or higher than the temperature at which the working medium is converted from the solid state or the liquid state to the gaseous state, and is lower than the temperature at which the housing expands to the maximum volume.

Further, after step S02, the method further includes:

step S03, printing layer by layer based on the print data of the three-dimensional object to be printed and overlapping the layer printing results to form the three-dimensional object, wherein the three-dimensional object comprises a solid structure and a support structure;

and step S04, removing the support structure in a dissolving or swelling mode to obtain a solid structure of the three-dimensional object.

In one embodiment, the support material may be a photocurable material and the curing mechanism in the printing apparatus is a photocurable mechanism. After step S03, and before step S04, the method further comprises:

step S031, cooling the three-dimensional object to accelerate the formation of the holes by the support structure of the three-dimensional object.

In another embodiment, the support material may also be a phase-change wax material or a hydrogel material, heated at a temperature equal to or higher than the temperature at which the working medium changes from a solid or liquid state to a gaseous state, and lower than the temperature at which the housing expands to its maximum volume. In this embodiment, a fan or a refrigerator may be used to cool the three-dimensional object, so as to accelerate the curing rate of the support structure, and the volume of the thermal expansion microspheres dispersed in the support material is reduced during the cooling and curing process, thereby forming the holes in the support structure. In the embodiment, after the support material is sprayed to the support platform for primary curing and forming, a fan or a refrigerator is used for secondary cooling treatment, so that the curing rate of the support structure is increased, and the aperture of the formed hole is increased.

Embodiments of the present application also provide a support material that includes thermally expandable microspheres, a photocurable host material, a non-curable water-miscible material, a photoinitiator, and an auxiliary agent. Wherein the thermally expandable microspheres are dispersed in the support material.

Specifically, the photocuring main body material is a (methyl) acrylate compound and/or a (methyl) acrylamide compound.

In one embodiment herein, the (meth) acrylate compound is a monofunctional (meth) acrylate compound and/or a multifunctional (meth) acrylate compound.

Still further, the monofunctional (meth) acrylate compound is selected from one or more of glycidyl methacrylate (molecular weight 142), 3- (acryloyloxy) -2-hydroxypropyl methacrylate (molecular weight 214), 2- (methacryloyloxy) ethyl 3-hydroxybutyrate (molecular weight 216), hydroxyethyl acrylate (molecular weight 116), 4-hydroxybutyl acrylate (molecular weight 144), polyethylene glycol (200) monoacrylate (molecular weight 450), polyethylene glycol (400) monoacrylate (molecular weight 912), methoxypolyethylene glycol (400) monoacrylate (molecular weight 842) and methoxypolyethylene glycol (550) monoacrylate (molecular weight 620).

Further, the polyfunctional (meth) acrylate compound is selected from one or more of pentaerythritol tetraacrylate (molecular weight 352), pentaerythritol triacrylate (molecular weight 298), polyethylene glycol (200) diacrylate (molecular weight 336), polyethylene glycol (400) diacrylate (molecular weight 508) and polyethylene glycol (600) diacrylate (molecular weight 708).

Further, the (meth) acrylamide compound is selected from one or more of acryloyl morpholine (molecular weight 141), dimethylacrylamide (molecular weight 99), diethylacrylamide (molecular weight 127), dimethylaminopropylacrylamide (molecular weight 156) and hydroxyethylacrylamide (molecular weight 115).

In a specific embodiment of the present application, the photocurable host material contains 15 to 30 parts by weight of a compound having a molecular weight of 300 or more and 3 to 6 parts by weight of a compound having a molecular weight of 277 or more than 50, based on the total weight of the support material. The compound may be a (meth) acrylate compound and/or a (meth) acrylamide compound. In the scheme of the application, the solubility of the photocured product of the support material in alkaline or water or aqueous solution is better by controlling the proportion of the compounds with different molecular weight ranges in the photocured host material.

Further, the multifunctional (methyl) acrylate compound in the photocuring main body material accounts for 0-4 parts by weight based on the total weight of the support material.

In another embodiment of the present application, the photocurable host material is selected from at least one of (meth) acrylate compounds and (meth) acrylamide compounds having a molecular weight of 300 or more, and at least one of (meth) acrylate compounds and (meth) acrylamide compounds having a molecular weight of 50 or more and less than 277.

In the support material of the present application, the non-curable water-miscible material is a polyol.

During the photocuring reaction of the support material, the non-curable water-miscible material is infiltrated into the network formed by the photocuring reaction, so that the dissolution rate of the product formed by photocuring the support material in water or an alkaline solution is further increased. A "water-miscible material" is itself in a liquid state and is at least partially soluble or dispersible in water, further for example at least 50% of the molecule is soluble in water when contacted (e.g., mixed) with water.

Further, the polyol may be one or more selected from the group consisting of polyol 3165, polyol 3610, EO/THF copolymer, polypropylene glycol, polyglycerol, 1, 2-propylene glycol, tripropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, triethylene glycol dimethyl ether, polyethylene glycol monomethyl ether (400), polyethylene glycol (400), and polyethylene glycol (200).

In one embodiment, the photoinitiator is a free radical photoinitiator.

Further, the radical photoinitiator may be one or more selected from benzoin ethyl ether, benzoin α -dimethylbenzyl ketal, α -diethoxyacetophenone, 2-hydroxy-2-methyl-phenylacetone-1, 1-hydroxy-cyclohexylbenzophenone, 2-isopropylthioxanthone, 2-hydroxy-2-methyl-p-hydroxyethyl ether-phenylacetone-1, 2-methyl-1- [ 4-methylthiophenyl ] -2-morpholino-1-propanone, [ 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 ], benzoyl ester, 2,4, 6-trimethylphenylacyl-ethoxy-phenylphosphine oxide, 2,4, 6-trimethylphenylacyl-diphenylphosphine oxide, bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide, and 4-p-tolylmercaptobenzophenone.

Further, the auxiliary agent is at least one selected from the group consisting of a surfactant, a polymerization inhibitor, a dispersant and a coloring agent.

The surfactant added into the support material has certain solubility in water or aqueous solution, and the main function of the surfactant is to adjust the surface tension of the composition so that the composition can be printed normally, and simultaneously improve the fluidity of the composition and the wetting property of a substrate. The polymerization inhibitor is added to prevent the free radicals in the composition from generating polymerization reaction and improve the storage stability of the composition, and the polymerization inhibitor is preferably a product which can improve the storage stability and has no influence on the light curing reaction of the composition. The dispersant is added to prevent the heat expandable microspheres from settling, so that the heat expandable microspheres can be uniformly and stably dispersed in the support material composition.

Further, the surfactant is selected from at least one of polyether modified siloxane and non-silicon polyether. The polyether-modified silicone may be, for example, various commercially available polyether-modified silicone surfactants, and may be, for example, at least one of BYK345, BYK346, BYK333, etc., at least one of TEGO wet 270, TEGO Glide 450, etc., from dygao, and at least one of AFCONA 3580, AFCONA 3585, AFCONA 3587, AFCONA 3588, etc. The non-silicon polyether may be various commercially available non-silicon polyether surfactants, and may be, for example, at least one of BYK800D, TEGO WET 500, TEGO Airex 920, TEGO Airex921, or AFCONA 3500, AFCONA 3590, or the like.

Further, the polymerization inhibitor may be at least one of reon products such as genrad 16, genrad 18, genrad 20, genrad 22, barsfer products such as Tinuvin234, Tinuvin770, Irganox245, cyanot S100, cyanot 130, etc., may be at least one of tuba products such as Irgastab UV10, Irgastab UV 22D, etc., may be at least one of amaq products of amadoraceae, usa, 510 products of hogel chemical ltd, etc.

Still further, the dispersant may be at least one of TEGO Dispers 685, TEGO-715W, etc., available from Digao; may be at least one of BYK-DISPERSANT-2013, DISPERBYK-2030, BYKJET-9150, etc.; may be at least one of the trade names EFKA-4009, EFKA4585, etc. of the EFKA company.

The colorant is selected from self-dispersing nano-scale pigment color paste, in particular self-dispersing nano-scale inorganic pigment color paste or self-dispersing nano-scale organic pigment color paste, wherein the self-dispersing nano-scale inorganic pigment color paste can be white pigment color paste, in particular titanium dioxide, zinc oxide, lithopone, lead white and the like, and can be black pigment color paste, in particular carbon black, graphite, iron oxide black, aniline black, carbon black and the like; the self-dispersing nano-scale organic pigment color paste can be color pigment color paste, and specifically comprises aurora red (PR21), lithol scarlet (PR 49: 1), pigment red G (PR37), pigment red 171(PR171), sun-proof yellow G (PY1), hansha yellow R (PY10), permanent yellow GR (PY13), pigment yellow 129(PY129), pigment yellow 150(PY150), pigment yellow 185(PY185), phthalocyanine blue (PB15), indanthrone (PB60) and the like.

Further, the support material of the present application comprises, based on 100% of the total weight of the components: 1-6% of thermal expansion microspheres, 18-40% of photocuring main material, 48-78% of non-curable water-miscible material, 1-5% of photoinitiator and 0.4-5% of auxiliary agent.

Examples of support materials and comparative examples listed in the present application are shown in table 1 below:

the embodiment of the application also provides a three-dimensional object which is formed by printing according to the printing method of the three-dimensional object, wherein the three-dimensional object comprises a solid structure and a supporting structure, and the supporting structure is provided with a plurality of holes.

When the three-dimensional object printed by the embodiment is soaked in water, aqueous solution, alkaline solution or other liquid, the liquid enters the inside of the supporting structure through the formed holes, so that the dissolving or swelling rate of the supporting structure is increased, the removing rate of the supporting structure is increased, the post-treatment efficiency of the three-dimensional object is improved, and the post-treatment cost of the three-dimensional object is reduced.

Using a cena J501 printer and the support materials listed in the present application and the support materials in the comparative examples, a 20mm by 20mm test piece was printed according to the three-dimensional object printing method in the examples of the present application, and left to cool naturally at room temperature after the printing was completed, after which the test piece was dissolved in an alkaline solution, which was a 2% NaOH aqueous solution, and the dissolution time was recorded, and the test results are shown in table 2.

TABLE 2 dissolution test results for test blocks

It can be seen from the above experiment that the molding material composition, on the premise of having the same composition (e.g., comparison between example 1 and comparative example 1, comparison between example 2 and comparative example 2), the support material with the thermal expansion microspheres added printed to form a support structure with holes, compared to the composition without the thermal expansion microspheres added, and the dissolution rate was faster than that of the support structure without holes when immersed in the alkaline solution.

In another embodiment, the support material includes thermally expandable microspheres, a phase change wax, and an auxiliary agent, which are not illustrated herein.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions, improvements, etc. within the spirit and principle of the present invention should be included in the scope of the present invention.