KR20240068293A - 3D Printer Regulating Gap between Nozzle and Object And Method thereof - Google Patents

Abstract

A 3D printer capable of maintaining the nozzle distance includes a printing head equipped with a nozzle that discharges the printing material onto the surface of the object, an arm stage that supports the printing head, and a nozzle distance that measures the separation distance between the nozzle and the surface of the object by combining it with the printing head or nozzle. It is provided with a stage control unit that controls the position of the arm stage so that the separation distance is maintained within a set range based on the separation distance received from the measuring unit and the nozzle distance measuring unit.

Description

3D printer capable of maintaining nozzle distance and method thereof {3D Printer Regulating Gap between Nozzle and Object And Method thereof}

Embodiments of the present disclosure relate to a 3D printer, and more specifically, to a 3D printer capable of maintaining a separation distance between a nozzle (more precisely, a nozzle end) and the surface of an object within a certain range.

The 3D printing process creates a 3D structure by converting a 3D drawing into an STL (Standard Tessellation Language) file and stacking it layer by layer based on a G-code file containing information that slices the 3D model into layers. .

3D printing is largely divided into FDM (Fused Deposition Modeling), SLA (Stereolithography), SLS (Selective Laser Sintering), and DIW (Direct Ink Writing).

The FDM method prints by injecting thermoplastic filament into a hot nozzle and discharging it. The FDM method prints by moving along (Plypropylene), etc. are used.

The SLA method is the oldest 3D printing technology and is based on the photopolymerization reaction of resin. A laser with a wavelength of 405 nm is used as a light source, and a galvo mirror is used to focus the resin and print it.

The SLS method is similar to SLA, but instead of using photoreactive resin, powder is used. A high-power laser selectively heats the powder and prints it layer by layer. After layer by layer printing, a new powder layer is formed and heated by the laser again.

The DIW method is known as a robocasting method, which prints by directly discharging semi-fluid. The ink used must have low viscosity before use and low viscosity after printing.

However, these 3D printing methods create a 3D structure by stacking two-dimensional pictures with a small thickness along the Z axis, and are not strictly a method of printing along the surface of the 3D structure.

When 3D printing according to a 3D model of a 3D structure for which information is already known, not only the coordinate error of the 3D model but also the relative coordinate error due to the absolute coordinate error of the 3D structure and the 3D printer nozzle is a tolerance that cannot be overcome during the 3D printing process. may occur. This relative coordinate error between the 3D structure and the 3D printer nozzle may cause damage to the 3D structure due to the nozzle, deformation of the shape of the ejected product, and instability of the 3D printing process on the surface of the 3D structure during the 3D printing process.

Embodiments of the present disclosure, due to relative coordinate errors between an object (e.g., a 3D structure) and a 3D printer nozzle, damage to the object by the nozzle, deformation of the shape of the ejected product, and damage to the 3D printing process on the surface of the 3D structure during the 3D printing process. We aim to provide a 3D printer that can maintain the nozzle distance within a certain range to prevent instability.

A 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure includes a printing head, an arm stage, a nozzle distance measuring unit, a stage control unit, etc.

The printing head may be provided with a nozzle that discharges the printing material onto the surface of the object.

The arm stage may support the printing head.

The nozzle distance measuring unit may be coupled to the printing head or nozzle to measure the separation distance between the nozzle and the object surface.

The stage control unit may control the position of the arm stage so that the separation distance is maintained within a set range based on the separation distance received from the nozzle distance measuring unit.

In a 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure, the nozzle distance measuring unit may include a lens optical fiber, a light source unit, a reference light generating unit, a nozzle distance calculating unit, etc.

The lens optical fiber may have a lens at the front end and be coupled to the nozzle so that the lens is located rearward than the end of the nozzle.

The light source unit may supply light through a lens optical fiber.

The reference light generator may generate reference light from light flowing in from the light source unit.

The nozzle distance calculation unit may calculate the separation distance using an interference phenomenon between the reference light and the reflected light reflected from the surface of the object after passing through the lens optical fiber.

In a 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure, the lens optical fiber may always be located in front of the direction in which the nozzle moves.

In a 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure, the printing head, nozzle, or arm stage may be configured to be rotatable.

In a 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure, the object may be a 3D structure with a three-dimensional curved surface, and the arm stage may be a 5-axis arm stage.

A method of maintaining the nozzle distance of a 3D printer according to another embodiment of the present disclosure includes a first step of initializing the position of the nozzle to which the lens optical fiber is coupled, a second step of setting the start coordinates and final coordinates of the nozzle, and setting the nozzle to the start coordinates. A third step of moving to, a fourth step of measuring the separation distance between the nozzle and the object surface, based on the measured optical fiber separation distance (L+△L), the optical fiber variation distance (△L) is changed from the optical fiber reference distance (L). The fifth step of determining whether the optical fiber is within the allowable distance (△L _target ). In the fifth step, if the optical fiber change distance (△L) is not within the optical fiber allowable distance (△L _target ), the optical fiber change distance (△L) is reduced. If the nozzle is further moved and the optical fiber change distance (△L) is within the optical fiber allowable distance (△L _target ), the sixth step is to perform printing. While performing printing, the nozzle is moved by the set interval (△D) to move to the next target coordinate. The seventh step is to terminate printing if the next target coordinate is the final coordinate, and if the next target coordinate is not the final coordinate, the eighth step is to measure the separation distance between the nozzle and the object surface again. After the eighth step, the fifth step described above is performed. Repeat the process of step 8.

In the method of maintaining the nozzle distance of a 3D printer according to another embodiment of the present disclosure, in the nozzle distance method described above, steps 1 to 5 are performed in the same manner, and after the sixth step, the nozzle is set at a set interval ( A seventh step of moving by △D) to the next target coordinate and then measuring the separation distance between the lens optical fiber and the object surface at the next target coordinate again; And in the 7th step, it is determined whether the next target coordinate is the final coordinate, and if it is the final coordinate, printing is terminated. If it is not the final coordinate, steps 5 to 7 are repeated, and then the next target coordinate is the final coordinate. It can be configured to perform judgment steps.

In the method of maintaining the nozzle distance of a 3D printer according to the present disclosure, the fourth step may indirectly measure the separation distance between the nozzle and the object surface by measuring the separation distance between the end of the lens optical fiber and the object surface.

According to embodiments of the present disclosure, the separation distance between the surface of the nozzle and the object (particularly, a 3D structure with a 3D curved surface) can be measured in real time and maintained within a certain range, thereby preventing the separation distance that may occur due to a relative coordinate error between the nozzle and the object. Damage to the object caused by the nozzle, deformation of the shape of the discharged product, and instability of the 3D printing process on the surface of the 3D structure can be resolved.

According to embodiments of the present disclosure, it is possible to print 3D surfaces with various curves, so 3D printing technology can be applied to areas that are already manufactured or difficult to apply in the process, such as connections between parts, device repair, and 3D electrical wiring. can do.

In addition, according to embodiments of the present disclosure, since a lens optical fiber equipped with a lens at the front end is used, the separation distance can be accurately measured without interference from external environments such as electricity and temperature as well as narrow spaces.

1 is a configuration diagram of a 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure.
Figure 2 illustrates a nozzle distance measuring unit of a 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure.
Figure 3 illustrates a state in which the stage control unit maintains the nozzle distance in a 3D printer capable of maintaining the nozzle distance according to an embodiment of the present disclosure.
Figure 4 is a flowchart explaining a method of maintaining the nozzle distance within a set range using a 3D printer according to another embodiment of the present disclosure.

Hereinafter, some embodiments of the present disclosure will be described in detail with reference to illustrative drawings. In adding reference numerals to components in each drawing, identical components may have the same reference numerals as much as possible even if they are shown in different drawings. Additionally, in describing the present disclosure, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description may be omitted. When “comprises,” “has,” “consists of,” etc. mentioned in the specification are used, other parts may be added unless “only” is used. When a component is expressed in the singular, it can also include the plural, unless specifically stated otherwise.

Additionally, in describing the components of the present disclosure, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, order, or number of the components are not limited by the term.

In the description of the positional relationship of components, when two or more components are described as being “connected,” “coupled,” or “connected,” the two or more components are directly “connected,” “coupled,” or “connected.” ", but it should be understood that two or more components and other components may be further "interposed" and "connected," "combined," or "connected." Here, other components may be included in one or more of two or more components that are “connected,” “coupled,” or “connected” to each other.

In the explanation of temporal flow relationships related to components, operation methods, production methods, etc., for example, temporal precedence relationships such as “after”, “after”, “after”, “before”, etc. Or, when a sequential relationship is described, non-continuous cases may be included unless “immediately” or “directly” is used.

On the other hand, when a numerical value or corresponding information (e.g. level, etc.) for a component is mentioned, even if there is no separate explicit description, the numerical value or corresponding information is related to various factors (e.g. process factors, internal or external shocks, It can be interpreted as including the error range that may occur due to noise, etc.).

Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the attached drawings.

1 is a configuration diagram of a 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure.

A 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure may include a printing head 110, an arm stage 120, a nozzle distance measuring unit 130, a stage control unit 140, etc.

The printing head 110 discharges the printing material, that is, the discharge material (P), on the surface of the object OB, and may be equipped with an extruder, a heating block, a cover, a nozzle (N), etc.

The extruder moves the printing raw material (e.g., thermoplastic resin such as filament) supplied from the printing raw material supply unit at a constant speed, and may include a micro-stepping motor, etc.

The heating block can change the filament from a solid state to a semi-liquid state by applying heat to the moving filament.

The cover may at least surround the heating block to block heat generated by the heating block from being emitted to the outside.

The nozzle (N) can discharge the filament, which has changed to a semi-liquid state while passing through the heating block, to the surface of the object (OB) through the front outlet. At this time, the nozzle N may maintain a certain distance from the surface of the object OB. Here, the object OB may be a 3D structure having a three-dimensional curved surface.

The arm stage 120 may be coupled to the rear of the printing head 110 to support it. The arm stage 120 may be a form capable of omnidirectional flow, for example, a 5-axis arm stage that flows (moves, rotates, etc.) in 5 axes (X, Y, Z, θ, Φ) directions.

One side of the nozzle distance measuring unit 130 is coupled to the printing head 110 or the nozzle (N) and can indirectly measure the separation distance between the nozzle (N) and the surface of the object (OB). The nozzle distance measuring unit 130 includes a lens optical fiber with a lens formed at the end, irradiates light R to the surface of the object OB, and then receives reflected light reflected from the surface of the object OB, and receives the reflected light R from the surface of the object OB. Measure the separation distance (L+△L) between (F) and the object (OB) surface. The nozzle distance measuring unit 130 will be described in detail later with reference to FIG. 2 .

The stage control unit 140 controls the position of the arm stage 120, and the optical fiber variation distance (△L) is the optical fiber allowable distance based on the optical fiber separation distance (L + △L) received from the nozzle distance measuring unit 130. Control the arm stage 120 to maintain within (△L _target ).

A 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure can control the lens optical fiber (F) to always be located in front of the direction in which the nozzle (N) moves. To this end, the printing head 110, nozzle (N), or arm stage 120 can be configured to be rotatable. For example, when rotating the printing head 110, the printing head 110 may be equipped with a rotation motor (not shown).

The front position control of the lens optical fiber (F) is, for example, provided with a discharge detection sensor that detects the discharge material (P), so that the lens optical fiber (F) is located on the opposite side of the direction in which the discharge material (P) is detected. (110) etc. can be controlled. Alternatively, the position movement of the nozzle N may be controlled so that the lens optical fiber F is always positioned in the direction of the next target coordinate based on the set current coordinate and the next target coordinate.

Figure 2 illustrates a nozzle distance measuring unit of a 3D printer capable of maintaining a nozzle distance according to an embodiment of the present disclosure.

As shown in FIG. 2, the nozzle distance measuring unit 130 is composed of a lens optical fiber (F), a light source unit 131, a reference light generating unit 132, a nozzle distance calculating unit 133, and a coupler 134. You can.

The lens optical fiber (F) may be provided with a lens (L) at its front end. The lens optical fiber (F) can be coupled to the nozzle (N) while the lens (L) is located rearward than the end of the nozzle (N). The nozzle (N) may have a tapered front shape, that is, a shape that protrudes in the center and slopes backward toward the side. In this case, the front end of the lens optical fiber (F), that is, the lens (L), is attached to the nozzle (N). It may be located in an inclined area.

The light source unit 131 supplies light (R) through a lens optical fiber (F), and in a nano 3D printer, for example, it can supply broadband light (R) of 100 nm. When measuring the separation distance (L+△L) between the optical fiber (F) and the surface of the object (OB) using the optical interference phenomenon, resolution of up to 3㎛ can be achieved by using 100㎚ broadband light.

The light source unit 131 may use, for example, a phase-locked pulse laser. A phase-locked pulse laser can emit laser light whose phase for each wavelength remains consistently synchronized over time, thereby relieving constraints on the optical path length while alleviating interference pattern formation constraints on the coherence length. The detailed structure of the phase-locked pulse laser is disclosed in Korean Patent No. 10-0942380, etc., which is used in this disclosure and detailed description thereof is omitted.

The reference light generator 132 generates and emits reference light from the light R incident from the light source unit 131, and may include a reference mirror, a scan driver, etc.

The reference mirror may reflect incident light and emit it.

The scan driver may adjust the phase change of the reference light by moving the position of the reference mirror in the light incident direction according to the control signal received from the nozzle distance calculation unit 133.

The nozzle distance calculation unit 133 uses the interference phenomenon between the reference light received from the reference light generator 132 and the reflected light reflected from the surface of the object OB after passing through the lens optical fiber F (L+△). L) can be calculated.

The nozzle distance calculation unit 133 may include a light detection unit. The light detection unit may detect overlapping light where the reference light and reflected light overlap through a coupler (or beam splitter) to be described later. The light detection unit may use, for example, a spectrometer.

The nozzle distance calculation unit 133 controls the scan driving unit that moves the reference mirror, and can obtain shape information about the surface of the object OB from the interference pattern of the overlapped light detected by the light detection unit. For example, height information on the surface of the object (OB) can be obtained by processing digital values corresponding to several interference patterns obtained by moving the reference mirror by a certain phase at equal intervals (i.e., changing the optical path). , using this, the separation distance between the optical fiber (F) and the object (OB) can be measured. Furthermore, since the distance difference between the end of the nozzle (N) and the end of the optical fiber (F) is determined during the manufacturing process, the measured separation distance between the end of the optical fiber (F) and the surface of the object (OB) is calculated from the end of the nozzle (N) and the surface of the object (OB). The nozzle separation distance can be calculated.

The coupler 134 branches and transmits the light emitted from the light source unit 131 to the reference light generator 132 and the lens optical fiber (F), and measures the reference light incident from the reference light generator 132 and the lens optical fiber (F). Light can be overlapped and transmitted to the nozzle distance calculation unit 133. The coupler 134 may include an isolator that selectively transmits or blocks light.

The coupler 134 described above can be replaced with a beam splitter or the like having a similar function.

Figure 3 illustrates a state in which the stage control unit maintains the nozzle distance in a 3D printer capable of maintaining the nozzle distance according to an embodiment of the present disclosure.

As shown in FIG. 3, based on the optical fiber separation distance (L+△L) measured through the nozzle distance measuring unit 130, the optical fiber variation distance (△L) is changed from the optical fiber reference distance (L) to the optical fiber allowable distance ( The stage control unit 140 can control the position of the arm stage 120 so that it is within △L _target ).

If the optical fiber change distance (△L) is not within the optical fiber allowable distance (△L _target ), the stage control unit 140 reduces the optical fiber change distance (△L) to ensure that the arm stage (△L target) exists within the optical fiber allowable distance (△L _target ). 120) can be controlled.

As shown in FIG. 3, the 3D printer capable of maintaining the nozzle distance according to an embodiment of the present disclosure measures the optical fiber separation distance (L+△L) between the front end of the lens optical fiber (F) and the surface of the object (OB). Therefore, an indirect method that maintains the separation distance between the end of the nozzle (N) and the surface of the object (OB) within a certain range (direct method in that it does not directly measure the distance between the end of the nozzle (N) and the surface of the object (OB) (named in an indirect way).

Figure 4 is a flowchart explaining a method of maintaining the nozzle distance within a set range using a 3D printer according to another embodiment of the present disclosure.

The method of maintaining the nozzle distance of a 3D printer according to another embodiment of the present disclosure may first perform a first step (S10) of initializing the position of the nozzle (N) to which the lens optical fiber (F) is coupled. In the first step (S10), the stage controller 140 may initialize the position of the printing head 110, that is, the position of the nozzle N, through control of the arm stage 120.

In the second step (S20), the user can set the starting and final coordinates of the nozzle (N). For example, when printing the number '1', the starting coordinates (3D example: X, Y, Z) may be (112,115,014), and the final coordinates may be (112,103,014).

In the third step (S30), printing can be prepared by moving the nozzle (N) to the set start coordinate. Here, the stage control unit 140 can change the position of the printing head 110, that is, the nozzle (N), through control of the arm stage 120.

In the fourth step (S40), the separation distance between the nozzle N and the surface of the object OB can be measured. Here, the nozzle distance measuring unit 130 can measure the optical fiber separation distance (L+△L) between the end of the optical fiber (F) and the surface of the object (OB).

In the fifth step (S50), the nozzle distance measuring unit 130 determines the optical fiber variation distance (△L) from the optical fiber reference distance (L) to the optical fiber allowable distance (△) based on the measured optical fiber separation distance (L+△L). L _target ) is determined.

In the fifth step (S50), if the optical fiber variation distance (△L) is not within the optical fiber allowable distance (△L _target ), the stage control unit 140 controls the arm stage 120 so that the optical fiber variation distance (△L) decreases. By additionally moving the nozzle (N), the optical fiber variation distance (△L) can be within the optical fiber allowable distance (△L _target ). If the optical fiber variation distance (△L) is within the optical fiber allowable distance (△L _target ), printing is performed.

In the sixth step (S60), the stage controller 140 controls the arm stage 120 to move the nozzle N by a set distance (△D) to the next target coordinate (e.g., 112, 114, 014).

In the sixth step (S60), while the nozzle (N) moves to the next target coordinate (e.g., 112,114,014), the nozzle (N) continuously performs printing while discharging the discharge material (P) onto the surface of the object (OB). do.

In the seventh step (S70), when the next target coordinates are the final coordinates (112, 103, 014), printing is terminated. If the next target coordinate is not the final coordinate, measure the separation distance (L+△L) between the optical fiber (F) and the surface of the object (OB), that is, perform the fourth step described above again.

Thereafter, the process of steps 5 to 7 described above is repeated until the next target coordinates are the final coordinates (112, 103, 014).

The nozzle distance maintenance method of a 3D printer according to another embodiment of the present disclosure may configure steps 6 and 7 differently from the nozzle distance maintenance method above. In other words, the process of moving the nozzle (N) by the set interval (△D) to the next target coordinate and the process of re-measuring the separation distance between the optical fiber (F) and the surface of the object (OB) at the next target coordinate are performed simultaneously or sequentially. It can be configured to perform it first and then determine whether the next target coordinate is the final coordinate. Since the remaining steps are the same as the nozzle distance maintenance method described above, detailed description of the related steps will be omitted.

The above description is merely an illustrative explanation of the technical idea of the present disclosure, and those skilled in the art will be able to make various modifications and variations without departing from the essential characteristics of the present disclosure. In addition, the embodiments disclosed in the present disclosure are not intended to limit the technical idea of the present disclosure, but rather are for explanation, and therefore the scope of the technical idea of the present disclosure is not limited by these embodiments. The scope of protection of this disclosure should be interpreted in accordance with the claims below, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of this disclosure.

110: printing head
120: arm stage
130: nozzle distance measuring unit
131: Light source unit
132: reference light generation unit
133: nozzle distance calculation unit
134: coupler
140: Stage control unit
F: optical fiber
L: lens
N: nozzle
OB: Object (3D structure)
P: Discharge (printing raw material)
R: Optical (broadband optical)
L+△L: Optical fiber separation distance
L: optical fiber standard distance
△L: Fiber variation distance
△Ltarget: Allowable distance of optical fiber

Claims (8)

A printing head having a nozzle that discharges a printing material onto the surface of an object;
an arm stage supporting the printing head;
a nozzle distance measuring unit coupled to the printing head or nozzle to measure the separation distance between the nozzle and the surface of the object;
A 3D printer capable of maintaining a nozzle distance, including a stage control unit that controls the position of the arm stage so that the separation distance is maintained within a set range based on the separation distance received from the nozzle distance measuring unit. The method of claim 1, wherein the nozzle distance measuring unit
a lens optical fiber having a lens at a front end and coupled to the nozzle so that the lens is located posterior to the end of the nozzle;
a light source unit supplying light to the lens optical fiber;
a reference light generator that generates and emits reference light from light incident from the light source unit;
A 3D printer capable of maintaining a nozzle distance, including a nozzle distance calculation unit that calculates the separation distance using an interference phenomenon between the reference light and reflected light reflected from the surface of the object after passing through the lens optical fiber. The method of claim 2, wherein the lens optical fiber
A 3D printer capable of maintaining the nozzle distance, located in front of the direction in which the nozzle moves. 4. The method of claim 3, wherein the nozzle, printing head, or arm stage is
A 3D printer that rotates and maintains the nozzle distance. According to any one of claims 1 to 4,
The object is a 3D structure with a three-dimensional curved surface,
The arm stage is a 5-axis arm stage, a 3D printer capable of maintaining the nozzle distance. A first step of initializing the position of the nozzle to which the lens optical fiber is coupled;
A second step of setting the starting and final coordinates of the nozzle;
A third step of moving the nozzle to the starting coordinates;
A fourth step of measuring the separation distance (L+△L) between the lens optical fiber and the object surface;
A fifth step of determining whether the change distance (△L) is within the allowable distance (△L _target ) from the reference distance (L) based on the separation distance (L+△L);
In the fifth step, if the change distance (△L) is not within the allowable distance (△L _target ), the nozzle is further moved so that the change distance (△L) decreases, and the change distance (△L) is adjusted to the allowable distance (△ A sixth step of performing printing if within L _target );
A seventh step of moving the nozzle by a set interval (△D) to the next target coordinate while performing printing;
An eighth step of terminating printing if the next target coordinate is the final coordinate, and re-measuring the separation distance between the lens optical fiber and the object surface if the next target coordinate is not the final coordinate;
After the eighth step, the method of maintaining the nozzle distance of a 3D printer includes repeating the eighth step in the fifth step. A first step of initializing the position of the nozzle to which the lens optical fiber is coupled;
A second step of setting the starting and final coordinates of the nozzle;
A third step of moving the nozzle to the starting coordinates;
A fourth step of measuring the separation distance (L+△L) between the lens optical fiber and the object surface;
A fifth step of determining whether the change distance (△L) is within the allowable distance (△L _target ) from the reference distance (L) based on the separation distance (L+△L);
In the fifth step, if the change distance (△L) is not within the allowable distance (△L _target ), the nozzle is further moved so that the change distance (△L) decreases, and the change distance (△L) is adjusted to the allowable distance (△ A sixth step of performing printing if within L _target );
A seventh step of moving the nozzle by a set distance (△D) while performing printing to the next target coordinate, and then measuring the separation distance between the lens optical fiber and the object surface at the next target coordinate again;
In the seventh step, it is determined whether the next target coordinate is the final coordinate, and if it is the final coordinate, printing is terminated. If it is not the final coordinate, the seventh step is repeated from the fifth step, and the next target coordinate is the final coordinate. How to maintain the nozzle distance of a 3D printer by re-determining whether it is a coordinate. The method of claim 6 or 7, wherein the fourth step is
A nozzle distance maintenance method for a 3D printer that indirectly measures the separation distance between the nozzle and the object surface by measuring the separation distance between the lens optical fiber and the object surface.

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