KR20230134396A - The apparatus of additive manufacturing and the method threrof - Google Patents

Abstract

The present invention relates to an additive manufacturing system and a method of additive manufacturing, wherein droplets are sprayed and the droplets adhere to a substrate or build platform by attraction control by an electric field, thereby forming at least one object in a layer-by-layer manner. A printing platform that forms a layer of; A flattening unit that flattens the laminate formed by the printing platform to a set height; a curing unit that cures the laminate flattened by the flattening unit; And, a controller that controls the printing platform, the flattening unit, and the curing unit, and is characterized in that the quality of additive manufacturing can be improved while significantly increasing the molding speed.

Description

Additive manufacturing system and method of additive manufacturing {THE APPARATUS OF ADDITIVE MANUFACTURING AND THE METHOD THREROF}

The present invention relates to an additive manufacturing system and method, and more specifically, to a system for additive manufacturing an object that can accurately and quickly form a laminate based on provided 3D model data.

The basic operations of the additive manufacturing system include slicing a three-dimensional computer model into thin cross-sections, converting the results into two-dimensional position data, supplying the data to a control device, and the control device forming three layers in a layered manner. It consists of manufacturing a dimensional structure.

Additive manufacturing involves numerous different fabrication methods (e.g., three-dimensional printing, thin film deposition, thermal melt deposition, etc.).

In three-dimensional printing processes, for example, building materials are dispensed from a dispensing head with a series of nozzles to deposit layers onto a support structure. Then, depending on the building material, the layer can be cured or solidified using an appropriate device. Building materials may include model materials (which form the object) and support materials (which support the object as it is built).

In additive manufacturing, prototypes of functional parts can be quickly produced with minimal investment in mechanical equipment and labor. This rapid prototyping can shorten the product development cycle and improve the design process by providing quick and effective feedback to designers.

Additionally, additive manufacturing can be used to rapidly manufacture non-functional parts, for example to evaluate various aspects of the design (e.g. aesthetic appearance, fit, assembly, etc.).

Additive manufacturing has also proven useful in the medical field (modeling predicted outcomes before performing treatments). In addition, fields that require visualizing specific designs or functions, such as architecture, dentistry, and plastic surgery, can benefit from rapid prototyping.

However, in many cases, the quality and accuracy of the laminated body for which laminated manufacturing was completed was significantly lower than the provided 3D data, and when the laminated material had low viscosity, there was a problem in that the molding speed was significantly lower.

In addition, in order to increase the molding speed, the viscosity of the laminated material must be increased, but in the case of high viscosity, there is a problem in that the material is not properly discharged.

In particular, when forming a 3D structure using inkjet printing, there was a problem that low viscosity ink had to be used.

1. Korean Patent Publication No. 2019-0127767 (2019.11.13.) “Pulse type light emitting diode sintering” 2. U.S. Patent Publication No. 2021-0308951 (2021.10.07.) “Method and system for additive manufacturing using closed-loop temperature control”

The object of the present invention is to solve the conventional problems as described above, and to provide an additive manufacturing system and a method for additive manufacturing that enable additive manufacturing at a rapid manufacturing speed by facilitating material discharge even when the laminated material has a high viscosity. The purpose.

In addition, the purpose is to provide an additive manufacturing system and a method for additive manufacturing that can improve the quality of accuracy of laminates for which additive manufacturing has been completed by applying EHD method or hybrid method to stacking.

The above problem is, according to the present invention, printing by spraying droplets so that the droplets adhere to a substrate or build platform by attraction control by an electric field to form at least one layer of the object in a layer by layer manner. platform; A flattening unit that flattens the laminate formed by the printing platform to a set height; a curing unit that cures the laminate flattened by the flattening unit; And, a controller that controls the printing platform, the flattening unit, and the curing unit.

Here, it may further include a neutralization unit that neutralizes the electric field after at least one layer is formed by the printing platform. At this time, the neutralization unit may be an ion generator.

Additionally, the printing platform includes at least one nozzle provided to discharge the material; an electrode formed in an area outside the discharge end of the nozzle; And, it is connected to a power source to form an electric field between the electrode and the laminate being formed on the build platform or the substrate or the build platform, and discharges charged droplets from the nozzle through voltage control to follow the electric field. It may include a voltage controller for electrodes that attach to the build platform.

In addition, the printing platform includes a piezoelectric actuator installed to generate a pressure wave to pressurize the material of the chamber toward the discharge end; And, it may further include a piezo voltage controller for driving control of the piezo actuator.

In addition, the controller includes a spatial distribution calculation unit that considers the spatial distribution of the electric field formed in the space between the nozzle, the laminate being molded, and the build platform; And, a trajectory calculation unit that estimates the trajectory in which the charged droplet flies along the electric field after being discharged from the nozzle; including a voltage magnitude or pulse signal supplied to each nozzle so that the droplet lands at the target point along the estimated trajectory. The nozzle can be controlled or the nozzle can be moved so that the droplet lands on the target point along the estimated trajectory.

In addition, the controller may determine the spatial distribution data of the electric field formed between the nozzle and the laminate being molded and the build platform according to the printing surrounding environment and the laminate material, and under the electric field after the charged droplet is discharged from the nozzle. A database in which trajectory data, which is a flying trajectory, is stored; And, a printing algorithm that analyzes the droplet impact point using machine learning on the spatial distribution data and the trajectory data accumulated in the database.

In addition, the flattening unit is provided with a pair of rollers, each rotating about an axis and arranged to contact each other and moved in the same direction by the controller, one of the pair of rollers is a hydrophobic roller, The other is provided as a receptor roller, so that the material adhering to the hydrophobic roller can be received and removed by the receptor roller.

Additionally, the receptor roller may be installed so as not to contact the material after the hydrophobic roller passes by. At this time, the curing unit may be provided with UV LED.

In addition, the inspection unit includes a camera that captures a surface image of the hydrophobic roller and a vibration sensor that measures vibration of the hydrophobic roller, and the controller detects the video image obtained from the camera and the vibration pattern obtained from the vibration sensor. By analyzing, it is possible to check whether the laminated state of the laminated body formed by the printing platform is abnormal.

In addition, it may further include a gantry unit that moves the printing platform in the x-direction, y-direction, and z-direction on the build platform.

Additionally, the nozzles are grouped into two groups, with the first group spraying droplets of 3 pL or less, and the second group spraying droplets of 50 pL or more.

Additionally, the first group can be controlled through vector scan, and the second group can be controlled through raster scan.

Additionally, the first group may form an edge region of the laminate, and the second group may form an inner region of the edge region. At this time, the first group may be a single nozzle, and the second group may be grouped as a multi-nozzle.

On the other hand, in the method of spraying droplets and attaching them by gravity control by an electric field to produce an object in a layer-by-layer manner, the voltage is controlled to discharge the droplets from the nozzle of the printing platform. A layer forming step of forming at least one layer of the laminate by causing the discharged liquid droplet to fly along the electric field and land on the substrate; A flattening step of controlling a flattening unit to flatten the layer to a set height; And, a curing step of controlling a curing unit to cure the layer flattened by the flattening unit, wherein the layer forming step, the flattening step, and the curing step are achieved by an additive manufacturing method controlled by a controller. You can.

In addition, the layer forming step includes forming an electric field between the printing platform and the substrate and applying a voltage through a voltage controller for electrodes to form a meniscus at the nozzle of the printing platform; And, applying a pressure wave to the chamber above the nozzle to control the voltage of the piezoelectric actuator so that the liquid droplet is ejected from the nozzle.

In addition, the layer forming step includes applying a voltage through a piezo voltage controller to form a meniscus in the nozzle of the printing platform by applying a pressure wave to the chamber above the nozzle; And, forming an electric field between the printing platform and the substrate, and controlling the voltage of the electrode voltage controller to discharge the liquid droplet from the nozzle.

In addition, it may be performed between or simultaneously with the layer forming step, the planarizing step, or the curing step, and may further include a neutralization step of neutralizing the electric field between the printing platform and the substrate.

According to the present invention, a layered manufacturing system and a layered molding method are provided that enable layered molding at a rapid molding speed by facilitating material discharge even when the layered material has a high viscosity.

In addition, an additive manufacturing system and a method of additive manufacturing that can improve the quality of accuracy of a laminate for which additive manufacturing has been completed by applying the EHD method or the hybrid method to stacking are provided.

Figure 3 is a detailed view of the printing platform of Figure 1;
Figure 4 is a longitudinal cross-sectional view of the nozzle of Figure 3;
5 is a schematic diagram of a hybrid inkjet nozzle;
Figure 6 is a schematic diagram showing the trajectory of a droplet flying along an electric field;
Figure 7 is a detailed view of the flattening unit of Figure 1;
Figure 8 is a detailed view of the curing unit of Figure 1;
Figure 9 is a detailed view of the inspection unit of Figure 1;
Figure 10 is a stack formation diagram by vector scan and raster scan;
Figures 11 and 12 are state diagrams of manufactured products using vector scan and raster scan;
13 is a diagram showing the stacking state of a laminate by an additive manufacturing system according to another embodiment of the present invention;
14 to 21 are schematic diagrams showing a process for additive manufacturing an object according to the present invention.

Prior to explanation, in various embodiments, components having the same configuration will be representatively described in the first embodiment using the same symbols, and in other embodiments, configurations different from the first embodiment will be described. do.

Hereinafter, a system for additive manufacturing an object according to a first embodiment of the present invention will be described in detail with reference to the attached drawings.

1 is a schematic diagram of a system for additive manufacturing an object according to the present invention. Referring to Figure 1, the system for additive manufacturing of objects according to the present invention (hereinafter referred to as "system") includes a build platform 10, a gantry unit 20, a printing platform 30, a flattening unit 40, and a curing unit. It consists of a unit 50, an inspection unit 60, and a controller 70.

The build platform 10 is a part on which a support object on which objects are stacked is placed. In this embodiment, the support object is a substrate P, but is not limited thereto.

The build platform 10 is grounded or voltage is applied so that an electric field is formed between the nozzle 32, which will be described later.

[Gantry unit]

Figure 2 is a plan view of the gantry unit of Figure 1. The gantry unit 20 is configured to move the printing platform 30, which will be described later, in the x and y directions. Specifically, the roller and printing platform of the gantry unit are supported on a Y rail, and the Y rail 22 is coupled to the X rail 21 at both ends.

Here, the printing platform 30 is mounted on the Y rail 22 using any of a variety of methods and devices known in the art such that the printing platform 30 is supported and moves along the Y rail 22.

Any of a variety of motors or actuators and devices for control known in the art may be used to move and accurately control the movement of the printing platform 30 along the Y rail 22.

The carriage 221 is mounted on both ends of the Y rail 22 and is coupled to the two X rails 21 at both ends of the Y rail 22 so that the Y rail 22 moves along the X rail 21. can do.

Movement and control of the carriage 221 along the X-rail 21 may be possible using any of a variety of motors or actuators and devices for control known in the art. For example, a stepper motor with a linear encoder or a piezoelectric motor may be used.

Meanwhile, the gantry unit 20 includes a platen gantry 23 configured to move the build platform vertically along the z-axis during fabrication of the substrate (see Figure 1).

Accordingly, as a layer of the substrate P is formed, the platen gantry 23 can lower the build platform vertically or along the z-axis as needed. Additionally, the platen gantry 23 may be configured to move the build platform along the x-axis, for example along a build path, to allow other processes to be performed on the substrate P.

[Print platform]

A system for additive manufacturing of objects according to the present invention may be a printing platform configured to perform an on-demand part manufacturing process to accurately build a 3D part or support portion for use in forming a portion of a 3D part.

Figure 3 is a detailed view of the printing platform of Figure 1; Referring to FIG. 3, the printing platform 30 may include a container 31, a nozzle 32, an electrode 33, and a voltage controller 34 for the electrode.

The printing platform 30 includes a supply system or molten pool of molten or consumable fluid material 311. The supply system is in the form of a molten pool configured to hold or produce molten or consumable fluid material 311 and includes a vessel 31 storing the molten or consumable fluid material 311 for dispensing.

The vessel 31 is equipped with a heater 312 (e.g., a heating element, heat piping, etc.).

Heater 312 may be located within vessel 31, under vessel 31, or along the side of vessel 31. Heater 312 may be controlled by controller 70 based, for example, on a temperature signal output from a temperature sensor indicating the temperature of consumable fluid material 311 within container 31 . The viscosity of the fluid material can be controlled through temperature control of the heater 312.

Printing platform 30 also includes one or more nozzles 32, each of which is configured to receive consumable fluid material 311 of container 31 through a corresponding channel 32a. When composed of a plurality of nozzles 32, they are arranged in an array as shown.

That is, the nozzles 32 may form an array and be distributed within a plane defined by the x-axis and y-axis. The nozzle 32 array is not limited to the shape as shown and may take on other shapes and configurations.

Meanwhile, in this embodiment, the consumable fluid material 311 is ink, and the viscosity and droplet size of the ink may be determined depending on the purpose of use, and is prepared as a conductive ink that further contains a conductive material to make it conductive. It could be.

Here, the ink droplet size (volume) may be smaller than 3 pL or larger than 50 pL, and viscosity may be 25°C and 20 cP or more.

Additionally, the nozzle 32 may be an EHD (Electro HydroDynamic) inkjet type nozzle or a hybrid inkjet type nozzle that combines the Piezoelectric type and the EHD inkjet type.

First, the nozzle of the EHD inkjet method will be described. Figure 4 is a longitudinal cross-sectional view of the nozzle of Figure 3. Referring to FIG. 4, the EHD inkjet nozzle 32 has an inlet end 321 on one upper side through which ink flows through the channel 32a, and a chamber where ink flowing in through the inlet end 321 is stored. 322 and a discharge end 323 through which ink is discharged may be included on one lower side of the chamber 322.

The electrode 33 is formed in an adjacent area (external in this embodiment) of the discharge end 323, and at this time, the electrode 33 is formed to cover the outside with an insulator (not shown) to prevent contact with ink. You can. Additionally, the electrode 33 can be connected to the electrode voltage controller 34 for voltage control.

Droplets can be jetted (discharged) by inducing electrostatic force to the meniscus formed at the discharge end 3212 by controlling the voltage of the electrode 33.

The voltage controller 34 for the electrode is installed to be connected to the electrode 322 and the substrate (P) or the build platform (10 in FIG. 2) through a high voltage power supply (not shown), and is connected to the nozzle 32 and the substrate (P) and the build platform 10 can generate and modulate a high potential difference. That is, through the electrode voltage controller 34, an electric field can be formed between the nozzle 32, the substrate P, and the build platform 10, and the formed electric field can be controlled. The electrode voltage controller 34 may control voltage modulation, etc. by its own algorithm, or may be controlled by the controller 70, which will be described later.

At this time, either the substrate P or the build platform 10 may be selectively connected to the electrode voltage controller 34, and even if the electrode voltage controller 34 is selectively connected to either of the electrode voltage controllers 34, the substrate P and build platform 10 may both be grounded or connected to a common potential.

Meanwhile, the electrode voltage controller 34 performs selective modulation of the voltage individually for each nozzle 32 in order to precisely control the discharge of ink droplets from each nozzle 32 to the substrate P. It may be possible.

According to the modulation of the electrode voltage controller 34 described above, the ink in the chamber 322 forms a meniscus at the discharge end 323, and the meniscus is discharged from the nozzle 32 and can be discharged as ink droplets. there is.

The ink droplet discharged from the nozzle 32 can be accurately landed at a desired location by charged droplet attraction-control by electric field. That is, individual droplets can fall onto the substrate P in a precise manner to form the stack m.

That is, an electric field is formed in the space between the nozzle 32, the substrate P, and the laminate m being stacked due to the voltage applied to the nozzle 32. The existing stack (m) formed on the substrate (P) forms the same potential (common potential) as the substrate (P), and as a result, the liquid droplet discharged from the nozzle 32 can be accurately deposited on the existing stack (m). there is.

Next, a hybrid inkjet type nozzle will be described. The hybrid inkjet method is a nozzle that combines the Piezoelectric method and the EHD inkjet method, and can improve printing performance by improving ejection precision.

Figure 5 is a schematic diagram of a hybrid inkjet nozzle. Referring to FIG. 5, the nozzle 32' of the hybrid inkjet method is a piezoelectric actuator that applies pressure to discharge liquid droplets to the discharge end 323 on the upper part of the nozzle 32 (upper part of the chamber 322) as shown in FIG. 5. (35) is configured, and a piezo voltage controller (36) connected to the piezo actuator (35) is further configured.

Here, the piezo actuator 35 may be provided with electrodes formed on the upper and lower surfaces centered on the piezoelectric body and driven in the vertical direction. And the piezo voltage controller 36 can be controlled by being connected to the controller 70, which will be described later.

In the case of the hybrid inkjet nozzle 32', the piezo voltage controller 36 for driving control of the piezo actuator 35 is configured to operate on the driving electrodes of the piezo actuator 35 (at least one of the electrodes formed on the upper and lower surfaces of the piezoelectric body). ) can be connected to. The piezo actuator 35 of this embodiment shows electrodes formed above and below the piezoelectric body, but it is not limited to this, and a piezo-type inkjet device with a different existing structure may be configured. Since details other than the above-mentioned configuration are already well-known, detailed descriptions other than this will be omitted.

The method of ejecting ink droplets with a hybrid inkjet nozzle is as follows. When the electrode voltage controller 34 applies voltage to the electrode 322, the liquid surface protrudes outward from the discharge end 323, forming a meniscus. At this time, the piezo actuator 35 is driven by the piezo voltage controller 36 to generate a pressure wave, and the pressure wave is transmitted to the discharge end 323 through the chamber 322 to push the meniscus outward. It is discharged as droplets by causing it to separate from the nozzle 32. At this time, droplets may be ejected simply by applying the voltage of the electrode voltage controller 34.

Meanwhile, the above-mentioned control method for discharging droplets is presented as an example, and the voltage signal applied to the piezo actuator 35 and the voltage signal applied to the electrode 33 are controlled according to a predetermined control method to discharge the droplets. You can. For example, droplets may be ejected by synchronizing the voltage signal applied to the piezo actuator 35 and the voltage signal applied to the electrode 33 with a certain time gap.

The principle of droplet adhesion using the above-described nozzle will be explained.

Figure 6 is a schematic diagram showing the trajectory of a droplet flying along an electric field. Referring to FIG. 6, the droplet discharged from the nozzle 32 is in a charged state, so the speed and flight trajectory of the droplet are determined by the relationship between the electric force due to the electric field distribution in space and the inertial force, gravity, and air resistance force due to discharge. It is decided.

The electric field formed in the space between the nozzle and the build platform is expressed by Maxwell's equations.

E is the electric field (V/m), ϕ is the voltage (V), ε is the dielectric constant (Coulomb/Vm), and ρ is the charge density (Coulomb/m ³ ).

The electric field obtained from the above equation is three-dimensional spatial information, and the electric force acting on the charged droplet existing in the electric field can be expressed as Coulomb force.

The flight speed and flight trajectory of a charged liquid droplet can be obtained from the following equation according to Newton's second law.

v is speed (m/s), t is time (second), g is gravitational acceleration, q _drop is the charge of the droplet (Coulomb), and m is the droplet mass (kg). You can also add air resistance to the right term.

Since the flight trajectory of the droplet varies depending on the spatial electric field distribution, the trajectory of the droplet must be controlled for an accurate stacking process. For this purpose, it is possible to control the magnitude and pulse of the voltage applied to the nozzle 32 using the voltage controller 34 and the nozzle driver 33.

For example, by lowering the magnitude of the voltage or shortening the duration of the applied pulse to reduce the amount of charge on the droplet, the strength of the electric force caused by the electric field can be lowered so that the droplet accurately lands on the target point along the estimated trajectory.

If the voltage magnitude and pulse control are not performed, the nozzle 32 can be controlled to move directly to suit the electric field in which the droplet is formed so that the droplet lands at the target point along the estimated trajectory.

Meanwhile, the controller 70, which will be described later, accumulates a database on the distribution of the electric field and the flight trajectory of the droplet, and the printer software that repeats the experiment continuously accumulates the data, so that the distribution of the electric field and the droplet's flight path formed from these data are accumulated. The trajectory can be estimated and the accuracy and precision of bullet impact can be improved. Here, lamination process optimization can be performed through droplet trajectory estimation using machine learning and AI algorithms.

The distribution of the electric field is determined by the location and shape of the nozzle 32 that applies the voltage, the size of the substrate (P), the material of the substrate (P), the surrounding printing environment, the viscosity of the ink, the density of the ink, the electrical conductivity of the ink, and the It may vary depending on the dielectric constant, etc. When performing a lamination process with specific ink by accumulating data on surrounding environmental variables and printer process variables, an optimal process using AI algorithms is possible.

Through this optimal process, the ink droplet discharged from the nozzle 32 can accurately land on the existing laminate (m).

Therefore, the printing platform 30 can precisely control the average diameter of the droplets (1pL to 100pL) within the range of about 1㎛ to about 100㎛ to accurately form a laminate (m) of the desired shape on the substrate (P). You can.

Additionally, the laminate (m) may be formed as a single layer, or may be formed by stacking multiple layers in a layer-by-layer manner.

[Neutralization unit]

The neutralization unit (Charge neutralization unit, 37 in FIG. 3) is provided with a soft It later serves to neutralize the electric field formed between the nozzle 32 and the substrate P. To this end, the neutralization unit 37 may be installed to move together with the container 31 or may be provided separately to perform the above function.

[Flatening unit]

Figure 7 is a detailed view of the flattening unit of Figure 1. Referring to Figure 7, the flattening unit is configured to rotate by contacting each other with a pair of rollers rotatably mounted on each roller shaft.

Of the pair of rollers, the first roller 41 is a hydrophobic roller and the second roller 42 is an acceptor roller, and the second roller 42 is relatively larger than the first roller 41. It is located at a high position and does not contact the pattern (m) flattened by the first roller (41). That is, the material that sticks to the first roller 41 while passing through the layer applied to the substrate P is removed through the second roller 42, and at this time, the second roller 42 is not in contact with the pattern m. Therefore, it can be maintained in a clean state.

Meanwhile, the material removed through the second roller 42 may be stored in a separate storage container (not shown).

The flattening unit is installed so that its moving direction moves in the same direction as the moving direction of the Y rail 21 of the gantry unit 20, and can be arranged to proceed behind the above-described printing platform 30 (FIG. 2 reference).

That is, the layer sprayed by the printing platform 30 and laminated on the substrate P can be flattened to a height set by the flattening unit 40.

In addition, the printing platform 30 can flatten each layer of the laminate (m) while moving along with it during stacking in a layer-by-layer type.

[Harding unit]

Figure 8 is a detailed view of the curing unit of Figure 1. Referring to FIG. 8, the curing unit 50 is provided with a UV LED or a UV laser and is configured to cure the laminate (m) laminated on the substrate (P).

The wavelength band and irradiation time of the curing unit 50 may vary depending on the material being laminated. In addition, when forming patterns such as electrodes or wiring on a substrate, a UV curing monomer or conductive ink with conductive particles dispersed is used as the lamination material. In this case, the conductive material of the lamination material is gold or silver. ), copper, graphene, mxene, etc. can be used to ensure conductivity.

Additionally, the curing unit 50 is provided to move with a separate transfer mechanism or printing platform 30 and can be controlled by the controller 70.

That is, the curing unit 50 cures the laminate m after the above-described flattening unit 40 flattens the laminate m.

[Inspection unit]

Figure 9 is a detailed view of the inspection unit of Figure 1. Referring to FIG. 9, the inspection unit 60 includes a camera 61, a vibration sensor 62, and an analysis unit 71.

The inspection unit 60 can inspect defects, curling, and shrinkage of the laminate (m).

To this end, the camera 61 acquires the surface state of the hydrophobic roller 41 as a video image and transmits it to the controller 70, and the analysis unit 71 analyzes the surface state of the hydrophobic roller 41 to determine the hydrophobic roller ( The state of the laminate (m) in contact with 41) can be analyzed.

In addition, when the vibration signal generated from the hydrophobic roller 41 is transmitted to the controller 70 through the vibration sensor 62 installed on the hydrophobic roller 41, the vibration pattern is analyzed in the analysis unit 62 to determine the hydrophobic roller 41. ) can be analyzed.

To this end, the analysis unit 71 is configured to compare and contrast the designed 3D model, object data of the laminate, and the vibration pattern of the hydrophobic roller 41.

In addition, the controller 70 may have the 3D model, object data, and vibration patterns of the laminate that can be compared and stored in the controller 70, or may be stored in a server connected through a network. .

As a result, the inspection unit 60 analyzes the video image and the vibration pattern together to determine defects, curling, and shrinkage of the laminate (m) flattened by the hydrophobic roller 41 in real time. You can check your back.

[controller]

Next, the controller in FIG. 1 will be described. The controller 70 may be one or more processors configured to execute instructions that may be stored locally in the system's memory or in a memory remotely connected to the system to control components to perform one or more functions of the system.

Controller 70 also includes one or more control circuits, microprocessor-based engine control systems, or digitally-controlled raster imaging processor systems, e.g., a host. The system may be configured to operate components of the system in a synchronized manner based on print commands received from a computer or remote location.

Controller 70 may then receive sliced layers of the desired 3D part or support structure, thereby allowing the system to generate the 3D part or support structure, for example, in a layer-by-layer manner.

In addition, the controller 70 may be configured with a circuit to control the above-described build platform, gantry unit, printing platform, curing unit, flattening unit, and inspection unit, and a sequence for sequentially operating the entire system may be configured. You can.

In addition, the controller 70 includes a spatial distribution calculation unit that considers the spatial distribution of the electric field formed between the nozzle 32, the laminate (m) being formed, and the build platform 10, and a charged liquid droplet is ejected from the nozzle. It may include a trajectory calculation unit that estimates the trajectory flying along the electric field.

That is, the voltage level or pulse signal supplied to each nozzle 32 can be controlled so that the droplet lands at the target point along the estimated trajectory. Alternatively, the nozzle 32 can be moved so that the droplet lands at the target point along the estimated trajectory.

Additionally, the controller 70 may further include a database in which data from the spatial distribution calculation unit and the trajectory calculation unit are stored, and a printing algorithm.

The spatial distribution data is the spatial distribution data of the electric field formed between the nozzle 32 and the laminate being printed and the build platform depending on the printing surrounding environment and the laminate material, and the trajectory data is the flight of the charged droplet under the electric field after being discharged from the nozzle. It may be trajectory data that is a trajectory.

The printing algorithm may be an algorithm that analyzes the droplet impact point through machine learning on spatial distribution data and trajectory data accumulated in a database.

The precision of the droplet's impact point can be further improved by the database and printing algorithm.

[Vector scan and raster scan]

In order to form at least one layer of the laminate (m), the controller 70 generally stacks the material according to the two-dimensional position data by using a printing platform (e.g., a print head, an extrusion nozzle) along some movement pattern. etc.) and the work surface.

Two types of motion patterns are known in the art, referred to as raster scan and vector scan.

Raster scanning is characterized by relative back and forth movement between the printing platform and the work surface, typically using multiple nozzles for parallel stacking.

During a raster scan, the printing platform visits all positions on the work surface by the gantry unit 20, where the controller can selectively activate and deactivate the nozzles of the printing platform for each position visited according to the two-dimensional position data.

In vector scan, the printing platform is controlled to move by the gantry unit 20 described above, but does not visit all locations on the work surface. Instead, material deposition moves along a selected path based on where it is needed.

For example, as shown in (a) of FIG. 10, a plurality of long-shaped structures (111, elognated structures) move along a path set by vector scan in the work area (100) of one layer (110). can be formed.

In addition, as shown in (b) of FIG. 10, the structure 111 may be a boundary structure that at least partially surrounds an area filled with the laminated material, and the boundary structure is connected to any one layer 60 by vector scanning. can be formed.

Additionally, as shown in (c) of FIG. 10, the structure 111 may be an interlayer connection structure connecting at least two layers 60 and 70. The structures in this example are preferably small (e.g., less than 1%) compared to the overall size of the layer.

Meanwhile, as shown in (a) of FIG. 10, the structure 111 may be included in an area formed by raster scanning. That is, the work area 100 of the layer 110 may be formed by raster scanning so that the structure 111 is embedded within the area 72.

Additionally, as shown in (d) of FIG. 10, the structure 111 may be a peripheral edge of one layer 110.

Product manufacturing using vector scanning and raster scanning is explained in detail. Figures 11 and 12 are state diagrams of manufactured products manufactured using vector scan and raster scan. Referring to FIG. 11, the manufactured product 200 includes a plurality of layers (110 in FIG. 10(a)) made of a non-conductive material and manufactured through three-dimensional printing, wherein one of the layers 110 is At least one may include:

A pattern 210 of conductive lines made of an electrically conductive material may be deposited on or formed in an area 220 of a non-conductive material.

Here, the pattern 210 can be manufactured by vector scanning, and the area 220 can be manufactured by raster scanning.

And, referring to FIG. 12, the device 300 is a large-area electronic device, such as an optoelectronic system, an active matrix display system, a projector display system, a sensor, an identification tag, a memory medium, and a smart card (e.g., a microprocessor card). , encryption cards, ATM cards, subscriber identity module cards (also known as SIM cards), projector displays, batteries, electronic components such as diode systems and transistor systems, etc.

That is, the manufactured product 200 is laminated in 3D using conductive and non-conductive materials using vector scan and raster scanning in any one area included in the device 300, or the manufactured product 200 is separately combined. can do.

Next, another embodiment of the additive manufacturing system according to the present invention will be described. Figure 13 is a diagram showing the stacking state of a laminate by an additive manufacturing system according to another embodiment of the present invention.

In the second embodiment of the present invention, nozzles are grouped into two groups. One group is configured to spray droplets of 3 pL or less, and the other group is configured to spray droplets of 50 pL or more. Here, the viscosity of the droplet may be 20 cP or more at 25°C.

If the nozzles are grouped into two groups as above, a large area such as area B sprays droplets of 50pL or more with a relatively large droplet size, and a small area such as area A, that is, the edge area, sprays droplets of relatively large size. Spray small droplets of 3pL or less.

Through this, the stacking speed of the laminate (m) can be improved.

Meanwhile, area B (large area) can be controlled through raster scan, and area A (small area) can be controlled through vector scan. In addition, during raster scanning, a large area can be quickly stacked using multiple nozzles, and when vector scanning requires precise formation of a small area, it can be controlled to form using a single nozzle.

Next, a manufacturing method using the additive manufacturing system according to the present invention will be described.

The method of additive manufacturing of an object according to the present invention is a method of forming an object by sequentially stacking at least one layer. Here, the nozzle 32 will be described as an example using a hybrid inkjet nozzle.

14 to 21 are schematic diagrams showing a process for additive manufacturing an object according to the present invention.

First, referring to FIG. 14, an electric field is formed between the printing platform 30 and the object to be laminated. That is, by applying voltage to the electrode voltage controller 34, an electric field is formed between the nozzle 32 and the substrate P. In this state, as shown in FIG. 15, the meniscus of ink is formed at the discharge end 323. Curse (M) is formed.

Then, in the state in which the meniscus (M) is formed, as shown in FIG. 16, when voltage is applied to the piezo actuator 35 through the piezo voltage controller 36, the piezo actuator 35 is driven to create the chamber 322. A pressure wave is generated, and the ink is pushed toward the discharge end 323 by the pressure wave, thereby ejecting the droplet D. The discharged liquid droplet (D) is deposited on the substrate (P) along the electric field formed between the nozzle and the substrate (P), thereby forming at least one layer (L).

Next, as shown in FIG. 17, the layer L is flattened to a set thickness using the flattening unit 40, and then, as shown in FIG. 18, at least one laminated layer is cured using the curing unit 50. .

At this time, the controller 70 analyzes the images and vibration signals received from the camera 61 and the vibration sensor 62 of the inspection unit (60 in FIG. 9) to detect layer defects and curling. and shrinkage, etc., can be checked in real time, and correction of the layer can be performed through a predetermined correction algorithm if necessary.

Thereafter, as shown in FIG. 19, the electric field formed between the nozzle 32 and the substrate P is neutralized using a neutralization unit 37 provided with an ion beam or the like. In this way, at least one layer is formed, and by repeating the order stored in the controller 70 at least once, multiple layers can be formed to form a stacked object.

Meanwhile, the neutralization step using the above-described neutralization unit 37 may be performed before, during, or after the planarization step or the hardening step, or may be performed simultaneously with either of the steps, if necessary.

Next, as another example of the method of forming the above-described layer, as shown in FIG. 20, a meniscus is formed in the nozzle by applying a voltage through a voltage controller for the piezo to generate a pressure wave into the chamber. Then, as shown in FIG. 21, an electric field can be formed between the printing platform and the substrate by applying voltage through the electrode voltage controller, and liquid droplets can be ejected from the nozzle.

The scope of the present invention is not limited to the above-described embodiments, but may be implemented in various forms of embodiments within the scope of the appended claims. It is considered to be within the scope of the claims of the present invention to the extent that anyone skilled in the art can make modifications without departing from the gist of the invention as claimed in the claims.

※Explanation of symbols for main parts of the drawing※
10 build platform
20 Gantry unit 21 Y rail
211 carriage 22 X rail
23 Platen Gantry
30 Printing Platform 31 Container
311 Consumable Fluid Materials 312 Heaters
32 nozzle 32a channel
321 inlet 322 chamber
323 discharge end 33 electrode
34 Voltage controller for electrodes 35 Piezo driver
36 Voltage controller for piezo
40 Flattening unit 41 First roller
42 2nd roller
50 curing unit 60 inspection unit
61 Camera 62 Vibration sensor
70 Controller 71 Analysis Department
100 work area 110,120 any one layer
111 structures
200 manufactured goods
300 devices

Claims (20)

A printing platform that sprays droplets and causes the droplets to adhere to a substrate or build platform by controlling attraction by an electric field to form at least one layer of the object in a layer-by-layer manner;
A flattening unit that flattens the laminate formed by the printing platform to a set height;
a curing unit that cures the laminate flattened by the flattening unit; and,
A controller that controls the printing platform, the flattening unit, and the curing unit. According to paragraph 1,
The additive manufacturing system further includes a neutralization unit that neutralizes the electric field after at least one layer is formed by the printing platform. According to paragraph 2,
A layered modeling system in which the neutralization unit is an ion generator. According to paragraph 1,
The printing platform is,
At least one nozzle provided to discharge the material;
an electrode formed in an area outside the discharge end of the nozzle; and,
It is connected to a power source to form an electric field between the electrode and the laminate or substrate being formed on the build platform or the build platform, and discharges charged droplets from the nozzle through voltage control to follow the electric field to the build platform. A additive manufacturing system including a voltage controller for electrodes that attach to the . According to paragraph 4,
The printing platform is,
a piezo actuator installed to generate a pressure wave to pressurize the material in the chamber toward the discharge end; and,
A layered manufacturing system further comprising a piezo voltage controller for driving control of the piezo actuator. According to paragraph 4,
The controller is,
a spatial distribution calculation unit that considers the spatial distribution of the electric field formed in the space between the nozzle, the laminate being formed, and the build platform; and,
Including a trajectory calculation unit that estimates the trajectory of the charged droplet flying along the electric field after it is discharged from the nozzle,
An additive manufacturing system that controls the voltage magnitude or pulse signal supplied to each nozzle so that the droplet lands at the target point along the estimated trajectory, or moves the nozzle so that the droplet lands at the target point along the estimated trajectory. According to clause 6,
The controller is,
Spatial distribution data of the electric field formed between the nozzle and the laminate being molded and the build platform depending on the printing surrounding environment and laminate material, and trajectory data, which is the trajectory of the charged liquid droplet flying under the electric field after being ejected from the nozzle. The database in which it is stored; and,
A printing algorithm that analyzes the droplet impact point using machine learning using the spatial distribution data and the trajectory data accumulated in the database. According to paragraph 1,
The flattening unit is provided with a pair of rollers,
Each is installed to rotate around an axis and is placed in contact with each other to move in the same direction by the controller,
One of the pair of rollers is a hydrophobic roller, and the other is a receptor roller, and the layered molding system accommodates and removes the material stuck to the hydrophobic roller in the receptor roller. According to clause 8,
An additive manufacturing system in which the receptor roller is installed so as not to contact the material after the hydrophobic roller has passed. According to paragraph 1,
The curing unit is an additive manufacturing system provided with UV LED. According to clause 8,
The inspection unit includes a camera that captures a surface image of the hydrophobic roller and a vibration sensor that measures vibration of the hydrophobic roller,
The controller analyzes the video image obtained from the camera and the vibration pattern obtained from the vibration sensor to inspect whether the laminated state of the laminated body formed by the printing platform is abnormal. According to paragraph 1,
An additive manufacturing system further comprising a gantry unit that moves the printing platform in the x-direction, y-direction, and z-direction on the build platform. According to paragraph 4,
The nozzles are grouped into two groups,
The first group is configured to spray droplets of 3 pL or less, and the second group is provided to spray droplets of 50 pL or more. According to clause 13,
An additive manufacturing system in which the first group is controlled through vector scan, and the second group is controlled through raster scan. According to clause 13,
The first group is to form an edge region of the laminate, and the second group is to form an inner region of the edge region. According to clause 15,
The first group is a single nozzle, and the second group is a multi-nozzle group. In the method of spraying droplets and causing the droplets to coalesce by gravity control by an electric field, forming an object in a layer-by-layer manner,
A layer forming step of controlling a voltage to discharge the liquid droplet from a nozzle of a printing platform, so that the discharged liquid droplet flies along the electric field and lands on the substrate, thereby forming at least one layer of the laminate;
A flattening step of controlling a flattening unit to flatten the layer to a set height; and,
A curing step of controlling the curing unit to cure the layer flattened by the flattening unit,
The layer forming step, the planarizing step, and the curing step are controlled by a controller. According to clause 17,
The layer forming step is,
Forming an electric field between the printing platform and the substrate and applying a voltage through a voltage controller for electrodes to form a meniscus at the nozzle of the printing platform; and,
Applying a pressure wave to a chamber above the nozzle to control the voltage of the piezoelectric actuator to eject the droplet from the nozzle. According to clause 17,
The layer forming step is,
Applying a voltage through a piezo voltage controller to form a meniscus in the nozzle of the printing platform by applying a pressure wave to the chamber above the nozzle; and,
Forming an electric field between the printing platform and the substrate, and controlling the voltage of the electrode voltage controller to discharge the liquid droplet from the nozzle. According to clause 17,
A method of additively manufacturing an object, which is performed between or simultaneously with the layer forming step, the planarizing step, or the curing step, and further includes a neutralization step of neutralizing the electric field between the printing platform and the substrate.

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