3D printing system for composite material

Abstract

The present invention provides a 3D printing system for composite materials. The system comprises a material receptacle having a base material contained therein; a laser project assembly configured to project a laser beam to the base material; a property modifier dispensing assembly having a property modifier for the base material contained therein and dispensing the property modifier to the base material; and a control system. The control system comprises a file storage assembly for storing 3D model files; a laser projection controlling assembly connected to the laser project assembly; and a property modifier dispensation controlling assembly connected to the property modifier dispensing assembly. The 3D printing system according to the present invention can determine different properties and appearances of each region of a workpiece as required and adjust the property modifier dispensation, including laser projection parameters and property modifier dispensation parameters, in accordance with a 3D workpiece to be formed.

Description

[0001] 3D PRINTING SYSTEM FOR COMPOSITE MATERIALS

[0002] TECHNICAL FIELD

[0003] The present invention relates to an engineering field involving a 3D printing system for composite materials.

[0004] BACKGROUND OF THE INVENTION

[0005] Forming 3D objects or workpieces using 3D printing technology is widely popular at present due to the rapid formation process, decreased loss of material texture, ability to produce complex workpieces, convenience in adjusting the design or size of workpiece, ability to accurately form both small and large workpieces, among other things. In addition, various materials can be used in the formation, such as plastic, metal, and ceramic materials, or metallic or polymeric composite materials like high-entropy alloys (HEA), high-entropy ceramics (HEC), and high-entropy polymers (HEP), etc.

[0006] Examples of prior art which are patent documents related to the formation of composite materials and 3D printing are as follows.

[0007] US 10,787,725 B2 discloses the manufacture of 3D workpiece from high-entropy alloy powder using a laser melting process. Such manufacturing process involves mixing the obtained high-entropy, powdered materials and processing them into powder for use as base material to be melted. However, the workpiece obtained from such a manufacturing process has a limitation in that the entire workpiece must be made of the same material.

[0008] US 5,204,055 discloses the manufacture of tooling and prototype parts and the use of 3D printing technology using computer models. The 3D workpiece of the present disclosure is made of a single-component material. Although the obtained workpiece is derived from a mixture of various materials, the mixing ratio of the present invention is the same for the entire workpiece.

[0009] US 2015 / 0375451 Al discloses a printer modified for printing 3D objects using material having two or more colors. The present invention uses a technology that can determine the supply of various materials to each workpiece by using two print heads to selectively output inks to obtain a multi-color workpiece. However, the invention relates to the melting process using the widely available plastic extrusion, and not the manufacture of workpiece using composite materials. US 6,259,962 B 1 discloses a 3D printer and a 3D printing method. Such printer includes an inkjet print head having a number of nozzles, a dispenser connected to the print head for selectively dispensing interface material in layers, and a curing means for optionally curing each of the layers deposited. The depth of each deposited layer is controllable by selectively adjusting the output from each of the nozzles. The injection mentioned in this document involves directly adding texture to the desired workpiece rather than adding a material property modifier, which changes the material’s properties through a chemical reaction.

[0010] WO 98 / 28124 A2 discloses method and apparatus for prototyping a three-dimensional object. A 3D printer can form 3D objects from powder by selectively applying a binder liquid to incremental layers of the powder. Such 3D printer uses inkjet print heads that can selectively dispense additives to the base material to form the binding. However, the present invention does not use laser to melt the materials and is not capable of adapting the laser intensity, projection pattern, and laser projection time to the varied workpiece components across different regions.

[0011] Although the patent applications disclosed above use composite materials to produce workpieces, particularly in conjunction with 3D printing, there has been no disclosure of the manufacture of composite materials by selectively adding a property modifier to specific region of the workpiece together with melting the materials using laser to form a workpiece.

[0012] Hence, there is a need to develop a 3D printing system for manufacturing composite materials that can determine the properties and control the ingredients in each region or the volume of a workpiece as needed for the applications. The system can also be applied to both current and future related technologies.

[0013] SUMMARY OF THE INVENTION

[0014] The present invention is aimed at developing an improved 3D printing system which provides enhanced printing and material formation efficiency. In particular, the invention is aimed at developing a 3D printing system which is particularly suitable for composite materials. The system is capable of producing composite materials and determining the properties of each region or the volume of a workpiece to be the same or different as needed for the applications. For example, the system can determine that some areas of the workpiece are friction-resistant and some areas, such as the interior, are highly thermally conductive by adjusting the property modifier dispensation parameters and the laser projection parameters to obtain composite materials with suitable properties. The workpiece obtained can thus be used in the applications while providing the desired specific mechanical or physical properties.

[0015] In a preferred embodiment, the present invention relates to a 3D printing system for composite materials comprising a material receptacle having a base material contained therein; a laser project assembly configured to project a laser beam to the base material; a property modifier dispensing assembly having a property modifier for base material contained therein and configured to dispense the property modifier to the base material; and a control system.

[0016] Preferably, the laser project assembly comprises a laser source and a laser direction adjusting device provided between the laser source and the material receptacle.

[0017] The control system comprises a file storage assembly for storing 3D model files, a laser projection controlling assembly connected to the laser project assembly, and a property modifier dispensation controlling assembly connected to the property modifier dispensing assembly.

[0018] According to the present invention, the 3D model files stored in the file storage assembly are read and the readable data is converted into laser projection pattern and property modifier dispensation pattern. The laser projection pattern is transmitted to the laser project assembly to project the laser beam to the base material using determined laser projection parameters, and the property modifier dispensation pattern is transmitted to the property modifier dispensing assembly to dispense the property modifier to the base material using determined property modifier dispensation parameters.

[0019] BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Fig. 1 is a diagram showing the components of the 3D printing system according to an exemplary embodiment of the present invention.

[0021] DETAILED DESCRIPTION

[0022] Different aspects and additional advantages of the present invention will become more apparent from the following details with reference to the accompanying drawing.

[0023] Any aspects shown herein shall encompass the application to other aspects of the present invention as well, unless stated otherwise.

[0024] Tools, devices, or methods mentioned herein shall mean tools, devices, or methods commonly used or practiced by a person skilled in the art, unless expressly stated to be tools, devices, or methods specific for the present invention. The terms “comprise,” “consist of,” “have / has,” “contain,” and “include” are open-ended verbs. For example, any methods which “comprise,” “consist of,” “contain,” or “include” one or more components or one or more steps are not limited to one or more components, or one or more steps indicated but shall also encompass components or steps that are not indicated.

[0025] Technical and scientific terms as used herein have meanings as understood by a person of ordinary skill in the art, unless specified otherwise.

[0026] The invention will now be described in more detail in conjunction with the accompanying drawing for better understanding.

[0027] Referring to Fig. 1, the 3D printing system for composite materials according to the present invention comprises a material receptacle (1) having a base material contained therein; a laser project assembly (2) configured to project a laser beam to the base material and comprising a laser source (2.1) and a laser direction adjusting device (2.2) provided between the laser source (2.1) and the material receptacle (1); a property modifier dispensing assembly (3) having a property modifier for the base material contained therein and configured to dispense the property modifier to the base material; and a control system (4) comprising a file storage assembly (4.1) for storing 3D model files, a laser projection controlling assembly (4.2) connected to the laser project assembly (2), and a property modifier dispensation controlling assembly (4.3) connected to the property modifier dispensing assembly (3).

[0028] According to the present invention, the 3D model files stored in the file storage assembly (4.1) are read and the readable data is converted into laser projection pattern and property modifier dispensation pattern, the laser projection pattern being transmitted to the laser project assembly (2) to project the laser beam to the base material using the determined laser projection parameters, and the property modifier dispensation pattern being transmitted to the property modifier dispensing assembly (3) to dispense the property modifier to the base material using the determined property modifier dispensation parameters.

[0029] The “ property modifier” according to the present invention can be any substances dispensed to the base material to modify any properties. The property modifier may be, but is not limited to, colorants, physical or chemical property modifiers, fragrances, etc., and may be any polymeric or metallic materials as required for mixing with the base material to obtain composite materials having the required properties.

[0030] The laser projection increases the energy required to change the material condition. Using only the latent energy stored in the property modifier or the material in its original state may not be sufficient to change the material condition. Therefore, using the additional energy from laser can help change the material condition in various ways and more completely than using only the energy from the property modifier.

[0031] According to a preferred embodiment, the 3D model files comprise 3D model geometric data and requirements for a formation of 3D model.

[0032] The geometric data may include characteristics and properties of the components needed to be formed, such as shape of each component, color gradients, color of each region, as well as the properties of the material in each region. For example, it may be model data for toy parts wherein the toy has a head, a body, and a base. The head may be circular and made of a textured, translucent material with facial features added to the surface. The body may be triangular and have color gradients. The base may have a spring-like shape and needs to be made of an elastic material.

[0033] The requirements for the formation of a 3D model may include determination of a laser projection power, a scan speed, and a laser projection pattern. For example, to create a model made of resin material with different property modifiers added, the resin part where a black material is added requires slower laser projection speed and higher laser power, whereas the laser projection of an elastic resin part with high shrinkage is performed by continuously projecting the laser in small spots, one at a time, to reduce the stress within the material.

[0034] According to an exemplary embodiment, the base material may be in a form of liquid, powder, solid, foam, a mixture of liquid and powder, a mixture of liquid and gas, or a combination thereof.

[0035] According to an exemplary embodiment, the property modifier for the base material may be in a form of liquid, solution, suspension, or a combination thereof.

[0036] According to a preferred embodiment, the property modifier dispensing assembly (3) is provided above the material receptacle (1) such that it is moveable along the horizontal or vertical direction or both, to dispense the property modifier to the base material.

[0037] According to an exemplary embodiment, the property modifier dispensing assembly (3) may be selected from an inkjet print head, a syringe, a liquid pump, a solenoid valve, or a combination thereof. The number of such devices can be adjusted as appropriate for the applications

[0038] Examples of the property modifier dispensation parameters are an amount of property modifier, a type of property modifier and a property modifier dispensation position, etc.

[0039] According to the above embodiment, the property modifier dispensation controlling assembly (4.3) serves to control the dispensation of property modifier by determining the amount of property modifier and the required ratio of property modifier, and controlling the movement of the property modifier dispensing assembly (3) to dispense the property modifier to the required position on the material receptacle (1). The property modifiers dispensed may react with each other or with the base material contained in the material receptacle (1), resulting in a change of material state. In the case of a liquid material, it becomes a solid through polymerization, crosslinking, or crystallization, for example. In the case of a powdered material, the powder particles attach to each other, resulting in solidification and the formation of the desired workpiece.

[0040] The movement of the laser project assembly (2) and the property modifier dispensing assembly (3) may be controlled by a control device which is developed based on a microcontroller system and Field Programmable Gate Array (FPGA).

[0041] Additionally, the 3D printing system according to the present invention may further comprise a stepping motor driving mechanism for controlling the movement of, for example, a print head, material scraper, and workpiece lifter, through a developed operating system and computer program.

[0042] According to the present invention, the laser projection parameters comprise parameters for controlling the laser source (2.1) and parameters for controlling the laser direction adjusting device (2.2).

[0043] Examples of the parameters for controlling the laser source (2.1) comprise a laser projection power, a laser projection pulse pattern, a laser intensity, a laser beam size, a wavelength used, a duration of projection, and a size of laser spot projected onto the base material.

[0044] As an example, adjusting the above parameters can result in uniform solidification of the material containing different property modifiers. For example, in a case where the base material is resin with dark pigments and a monomer with slow reaction rate, a longer laser projection time is required to obtain hardness and solidification depth equivalent to those of transparent resin with no property modifier. Also, in a case where the property modifier is added to a material which is iron-based metal powder with added tungsten, it is required to increase the laser power so that such alloy receives sufficiently high energy to cause the melting.

[0045] An example of the parameters for controlling the laser direction adjusting device (2.2) comprise angles of laser reflection.

[0046] According to an exemplary embodiment, the laser used may have a wavelength ranging from 190 nm to 11 pm. The laser projection power may be in a range of 5 mW to 20 kW. The size of the laser beam spot projected onto the base material may be in a range of 50 to 200 pm. However, the laser beam shape is not limited to a circle and can take other forms, such as a square, hexagon, or other shapes as appropriate.

[0047] According to a preferred embodiment, the laser direction adjusting device (2.2) comprises a mirror, and optionally a focusing lens, which allows the laser beam to be projected onto the printing plane with consistent laser power and laser beam size. The focusing lens also allows the light energy to effectively focus on the surface. The operation of the 3D printing system according to the present invention may require only the mirror or both the mirror and the focusing lens.

[0048] According to an exemplary embodiment, the mirror used in the 3D printing system according to the present invention is a galvo mirror with a response rate ranging from 1-500 KHz. An example of the focusing lens used in the 3D printing system according to the present invention is an F-Theta lens.

[0049] According to the above embodiment, the laser projection controlling assembly (4.2) serves to control the laser source (2.1) and the laser direction adjusting device (2.2). For example, it controls the galvo mirror to turn to the required angle to reflect the laser beam emitted from the laser source (2.1) to the base material, resulting in a change of material condition, i.e. solidification of liquid material, binding, or homogeneous melting of the base material in a case where it is in powder form. The laser projection controlling assembly may also adjust the laser projection pattern to correspond to the ingredients of the base material and the amount of property modifier.

[0050] The 3D printing system according to the present invention may further comprise an operation inspection assembly (5) connected to the laser projection controlling assembly (4.2), and the property modifier dispensation controlling assembly (4.3) to inspect the 3D printing operation in real time. According to a preferred embodiment, the operation inspection assembly (5) comprises an imaging device (5.1) disposed proximal to the material receptacle (1) to capture images of radiation and heat emission from the base material, which has been treated with laser and the property modifier; and a processor (5.2) for processing the images obtained from the imaging device (5. 1) and transmitting the processed data to the property modifier dispensing assembly (3) to adjust the property modifier dispensation parameters and to the laser project assembly (2) to adjust the laser projection parameters.

[0051] An example of the imaging device (5.1) which can be used in the 3D printing system is a camera configured to capture visible light and infrared.

[0052] The operation inspection assembly (5) receives the data from the imaging device (5.1), which detects the radiation emission. The emitted radiation may be visible light and infrared. The detection is intended to indicate the occurrence of reaction and the melting of the material. For example, the reaction can result in a change in absorbance and fluorescence emission. On the other hand, the melting of the material can be detected by measuring the thermal radiation from a black body. The detection of the material composition can be achieved through the radiation resulting from a change in electron energy level from a higher orbital to a lower orbital after receiving energy from the laser treatment. Upon detecting the occurrence of reaction and the melting of the material, the formation status and the reaction process are accurately and promptly provided.

[0053] The operation inspection assembly (5) enables the 3D printing system according to the present invention to inspect the formation quality and the reaction in real time by transmitting the real-time formation status to the property modifier dispensing assembly (3) to adjust the property modifier dispensation parameters, and to the laser project assembly (2) to adjust the laser projection parameters in a prompt and continuous manner. Therefore, the formation is effective, resulting in a workpiece that exhibits the desired properties.

[0054] The laser projection controlling assembly (4.2), the property modifier dispensation controlling assembly (4.3), and the operation inspection assembly (5) may be developed on a Field Programmable Gate Array (FPGA) processor chip, which receives and processes an image signal from the imaging device (5.1). A Non-Volatile Memory Express (NVME) data storage system is also used to store the 3D model files to be printed which are stored in the file storage assembly (4.1). Example

[0055] The present invention will now be described in more detail with reference to the examples of the invention to be mentioned hereinafter. The examples of the invention shown herein are not intended to limit the scope of the invention in any way.

[0056] Example of the manufacture of a 3D workpiece from metal powder material

[0057] The process was carried out using the laser source with a wavelength of 880 nm and the laser power of 200 W, which is high enough to melt the metal powder material such as SS400 steel having a particle size of approximately 15 pm. The laser beam emitted was projected onto the galvo mirror at a response rate of 50 KHz. The laser beam then passed through the F-Theta focusing lens, allowing the laser beam to focus on the printing plane of the base material. The F-Theta focusing lens selected for the laser beam with a wavelength of 880 nm has a lens dimension of 80 mm and a focal distance of 100 mm. The laser to be projected onto the base material, such as SS400 steel, has a diameter of the laser spot ranging from 50-200 pm, which is sufficient to melt said metal powder material. Furthermore, adjusting the size of the laser spot not only serves to melt the base material but also can expand the spot size of the laser to warm the powdered material, ensuring consistent heat distribution across the entire workpiece during the melting process.

[0058] The alloy workpiece was then subjected to property modification. For example, in a case where a workpiece with a corrosion-resistant surface is required, a property modifier, such as chromium, can be added to obtain stainless steel. The property modifier dispensing assembly would then be operated to dispense chromium particles in a suspension form to the base material. After mixing chromium with the steel base material, an alloy material would be obtained. Moreover, in a case where thermal conductivity is required, such as for producing a workpiece that is part of a cooling system, a property modifier like copper can be dispensed to the base material to provide the workpiece with thermal conductivity.

[0059] Example of the manufacture of a 3D workpiece from polymer

[0060] The process was carried out using the laser source with a wavelength of 405 nm and the laser power of 5 W, which is high enough to cause polymerization of a liquid resin material, such as a liquid resin material which is a mixture of acrylate and epoxy monomers based on free-radical and cationic crosslinking. Such resin was contained in the material receptacle. The laser beam emitted was projected onto the galvo mirror at a response rate of 50 KHz. The laser beam then passed through the F-Theta focusing lens, allowing the laser beam to focus on the printing plane of the base material. The F-Theta focusing lens selected for the laser beam with a wavelength of 405 nm has a lens dimension of 80 mm and a focal distance of 100 mm. The laser to be projected onto the base material has a diameter of the laser spot of approximately 50 pm, which is sufficient to cause polymerization.

[0061] Optionally, the scanning pattern may start from the peripheral edge of the workpiece, followed by the inner area of the workpiece. This step initiates gelation and, subsequently, a full solidification of the resin. The gelation creates an area where the property modifier can be added in a controllable manner.

[0062] The polymeric workpiece was then subjected to property modification. For example, in a case where a multi-color workpiece is required, the property modifier dispensing assembly, such as inkjet head print containing primary colors which have been dissolved in a solvent like cyan, magenta, yellow, black, would dispense the required primary colors onto the surface of the base material to obtain a multi-color workpiece. On the other hand, in a case where a partially soft workpiece is required, the property modifier dispensing assembly containing a substance consisting of urethane monomer dissolved in a volatile, inert solvent which helps enhance the elasticity property and impact resistance, would dispense the property modifier onto the surface of the base material. The addition of such a monomer would allow the region of the workpiece which has been subjected to property modification to become softer than other regions.

[0063] The 3D printing system according to the present invention having different characteristics as described above can be used to conveniently form a workpiece made of composite materials which can be applied to various applications by adjusting the property of each part or region of the workpiece to match the need by adjusting the property modifier and parameters related to the printing. For example, in a case where the system is used to construct a rocket’s engine room using powdered metal, wherein some parts require thermal resistance, others require thermal conductivity, and high-strength structural components are needed, different property modifiers can be added. For example, tungsten may be added to the region with direct heat exposure to provide such region with thermal resistance, copper may be added to the parts requiring good heat exchange, and titanium may be added to reduce the weight and increase structural strength.

[0064] The 3D printing system for composite materials disclosed and claimed in the present invention is intended to encompass the aspects of the invention that are obtained from any actions, practices, modifications or changes in factors without carrying out experiments substantially different from the present invention, and is intended to provide properties, utility, and effects similar to those of the present invention, as understood by a person of ordinary skill in the art, although not specifically stated in the claims. Therefore, substitutions or analogues of the aspects of the present invention, including any slight modifications or changes apparent to a person of ordinary skill in the art, should also be considered to be within the spirit, scope, and concept of the present invention.

[0065] BEST MODE OF THE INVENTION

[0066] Best mode of the invention is as described in the detailed description of the invention.

Claims

WHAT IS CLAIMED IS:

1. A 3D printing system for composite materials comprising: a material receptacle (1) having a base material contained therein; a laser project assembly (2) configured to project a laser beam to the base material and comprising a laser source (2.1) and a laser direction adjusting device (2.2) provided between the laser source (2.1) and the material receptacle (1); a property modifier dispensing assembly (3) having a property modifier for the base material contained therein and configured to dispense the property modifier to the base material; and a control system (4) comprising a file storage assembly (4.1) for storing 3D model files, a laser projection controlling assembly (4.2) connected to the laser project assembly (2), and a property modifier dispensation controlling assembly (4.3) connected to the property modifier dispensing assembly (3) wherein the 3D model files stored in the file storage assembly (4.1) are read and the readable data is converted into laser projection pattern and property modifier dispensation pattern, the laser projection pattern being transmitted to the laser project assembly (2) to project the laser beam to the base material using determined laser projection parameters, and the property modifier dispensation pattern being transmitted to the property modifier dispensing assembly (3) to dispense the property modifier to the base material using determined property modifier dispensation parameters.

2. The system according to claim 1, wherein the 3D model files comprise 3D model geometric data and requirements for a formation of 3D model.

3. The system according to claim 1, wherein the base material is in a form of liquid, powder, solid, foam, a mixture of liquid and powder, a mixture of liquid and gas, or a combination thereof.

4. The system according to claim 1, wherein the property modifier for the base material is in a form of liquid, solution, suspension, or a combination thereof.

5. The system according to claim 1, wherein the property modifier dispensing assembly (3) is provided above the material receptacle (1) such that it is movable along the horizontal or vertical direction or both.

6. The system according to claim 1, wherein the property modifier dispensing assembly (3) is selected from an inkjet print head, a syringe, a liquid pump, a solenoid valve, or a combination thereof.

7. The system according to claim 1, wherein the property modifier dispensation parameters comprise an amount of property modifier, a type of property modifier, and a property modifier dispensation position.

8. The system according to claim 1, wherein the laser projection parameters comprise parameters for controlling the laser source (2.1) and parameters for controlling the laser direction adjusting device (2.2).

9. The system according to claim 8, wherein the parameters for controlling the laser source (2.1) comprise a laser projection power, a laser projection pulse pattern, a laser intensity, a laser beam size, a wavelength used, a duration of projection, and a size of laser spot projected onto the base material.

10. The system according to claim 8, wherein the parameters for controlling the laser direction adjusting device (2.2) comprise angles of laser reflection.

11. The system according to claim 9, wherein the wavelength used is in a range of 190 nm to 11 pm and the laser projection power is in a range of 5 mW to 20 kW.

12. The system according to claim 1, wherein the laser direction adjusting device (2.2) comprises a mirror, and optionally a focusing lens.

13. The system according to claim 12, wherein the mirror is a galvo mirror with a response rate ranging from 1-500 KHz.

14. The system according to claim 12, wherein the focusing lens is an F-Theta lens.

15. The system according to claim 1 further comprising an operation inspection assembly (5) connected to the laser projection controlling assembly (4.2), and the property modifier dispensation controlling assembly (4.3) to inspect the 3D printing operation in real time.

16. The system according to claim 15, wherein the operation inspection assembly ( 5) comprises an imaging device (5.1) disposed proximal to the material receptacle (1) to capture images of radiation and heat emission from the base material, which has been treated with laser and the property modifier; and a processor (5.2) for processing the images obtained from the imaging device (5.1) and transmitting the processed data to the property modifier dispensing assembly (3) to adjust the property modifier dispensation parameters and to the laser project assembly (2) to adjust the laser projection parameters.

17. The system according to claim 16, wherein the imaging device (5.1) is a camera configured to capture visible light and infrared.

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