KR20210141209A - 3d printing apparatus and method - Google Patents

Abstract

The present invention relates to 3D printing device and method which accurately calculate an amount of a binder to be sprayed to powder in order to print a high quality of an output. As the 3D printing device capable of printing powder, which is a material of an output, in a binder jet method, the 3D printing device according to one embodiment of the present invention comprises a case which provides an output space where the powder is supplied to be output; a building plate which is disposed in the output space of the case to be elevated; and a measuring plate which is disposed at an upper side of the building plate to measure the mass of the powder supplied to the output space.

Description

3D printing apparatus and method

The present invention relates to a 3D printing apparatus and method, and more particularly, to a 3D printing apparatus and method capable of printing a high-quality output by accurately calculating the amount of a binder to be sprayed on a powder.

3D printing is a technology for forming three-dimensional structural products, and has the advantage of not only rapidly forming three-dimensional structures, but also producing shapes that cannot be assembled/disassembled. Such 3D printing has long since started full-scale research, and conventionally, there are limits to materials that can be 3D printed, and the equipment is expensive, so it is widely used in limited fields such as aerospace-related parts production or prototype production of automobiles, etc. However, it has been widely used in various fields recently, and its application area is expanding.

3D printing technology is broadly classified into FDM (Fused Deposition Modeling) method using solid material, SLA (Setero Lithography Apparatus) method and DLP (Digital Lighting Processing) method using liquid material, SLS using powder material Various methods such as (Selective Laser Sintering) method are being implemented.

Among 3D printing technologies, the binder jet method is a method of spraying a liquid binder onto a powder bed in which powder is thinly stacked.

1 is a view showing a 3D printing technology of a general binder jet method.

As shown in (a) of FIG. 1 , the powder, which is the material of the output Pr, is supplied to the upper portion of the building plate 20 provided in the output space. And the upper surface of the supplied powder (P) is arranged flat using the powder coater (40). The layer formed at this time will be referred to as an n-layer.

If the n-layer is formed in this way, as shown in FIG.

And, by curing the binder (B) sprayed on the n-layer using the binder curing means 60 as shown in (c) of FIG. P+B) is formed as the output Pr. At this time, the region in which the binder (B) is not mixed among the n-layer remains as the second region Pl maintained in a powder state.

If the first region P+B is formed as a part of the output Pr, the building plate 20 is lowered by an n-layer thickness as shown in FIG. 1D.

Then, the n+1 layer is formed by supplying the powder (P) to the upper portion of the n-layer.

When the n+1 layer is formed in this way, the above process is sequentially repeated to obtain an output having a desired shape.

If the above process is repeated to obtain an output having a desired shape, the output is unloaded from the building plate 20, and the second area Pl remaining around the output Pr is removed to obtain an output of the output Pr. complete the output.

On the other hand, the general binder jet 3D printing technology has a problem in that the use of the shape and particle size of the powder is limited in order to form a high-quality three-dimensional output.

The strength of the 3D printout is determined by the type of powder and binder used as a material and the curing state of the binder.

Therefore, in the prior art, since mono-dispersed spherical particles were used as a powder, there were many problems in the selection of materials, and there was a disadvantage that the particle size and shape of the powder must be precisely controlled.

The content described as the background art above is only for understanding the background of the present invention, and should not be taken as an acknowledgment that it corresponds to the prior art already known to those of ordinary skill in the art.

Laid-Open Patent Publication No. 10-2018-000011153 (2018.01.31)

The present invention provides a 3D printing apparatus and method capable of printing a high-quality output as the powder is supplied and the pore volume of the formed layer is derived, and the amount of the binder to be sprayed on the powder is accurately calculated and sprayed.

A 3D printing apparatus according to an embodiment of the present invention is a 3D printing apparatus for printing a powder as a material of an output by a binder jet method, comprising: a case providing an output space through which the powder is supplied and output; a building plate arranged to be raised and lowered in the output space of the case; and a measuring plate disposed on the upper surface of the building plate to measure the mass of the powder supplied to the output space.

a powder coater disposed on the upper part of the case to flatten the powder supplied to the output space of the case; a binder spraying means disposed on the upper portion of the case and spraying the binder in a designed pattern and amount to the powder supplied to the output space of the case; It further includes a binder curing means disposed on the upper portion of the case to expose the curing source to the binder to cure the binder.

A control unit for calculating the pore volume of the area to which the powder is supplied by using the mass value of the powder measured by the measuring plate, and adjusting the amount of the binder sprayed as powder from the binder spraying means according to the calculated pore volume. characterized in that

The control unit calculates the packing density of the supplied powder using the measured mass value of the powder, and calculates the pore volume of the powder supplied region using the calculated packing density.

The measurement plate is partitioned for each area and measures the mass of the powder supplied to the output space for each area.

On the other hand, a 3D printing method according to an embodiment of the present invention is a 3D printing method for printing a powder, which is a material of an output, in a binder jet method, comprising: a powder supplying step of supplying the powder to an output space; A layer forming step of flattening the supplied powder using a powder coater to form an n-layer; a mass measurement step of measuring the mass value of the n-layer; a binder amount determination step of determining the amount of the binder sprayed to the n-layer using the measured mass value of the powder; a spraying step of spraying the determined amount of binder on the n-layer in a pattern designed according to the shape of the output; and a curing step of curing the binder by irradiating a curing source to the binder sprayed on the n-layer.

The mass measurement step is characterized in that the n-layer is partitioned for each region and the mass for each region is separately measured.

The binder amount determining step is characterized by calculating the pore volume inside the n-layer to which the powder is supplied by using the measured mass value of the n-layer, and determining the amount of the binder in the calculated pore volume.

The binder amount determining step calculates the volume of the powder supplied to the n-layer using the theoretical density of the powder supplied to the n-layer and the measured mass value of the n-layer, and the calculated volume of the powder and the total volume of the n-layer It is characterized in that the pore volume inside the n-layer is calculated by comparing the

The binder amount determining step derives a correction amount by comparing the amount of the binder determined in real time with the amount of the initially set binder, and correcting the initially set amount of the binder according to the derived correction amount.

After the curing step, it is characterized in that the powder supply step to the curing step are sequentially repeated a plurality of times with respect to the upper portion of the n-layer.

According to an embodiment of the present invention, the effect of realizing a high-quality output can be expected by accurately determining the amount of the binder to be sprayed by deriving the pore volume of the layer formed by being supplied to the building plate.

In addition, since the amount of the binder is determined by measuring the mass of the powder during the process, 3D printing can be performed using irregular or various types of powder without limiting the particle shape of the powder.

Accordingly, since there is no need to precisely control the particle size and shape of the powder in any material group, the cost for selecting or providing a material can be reduced.

1 is a view showing a 3D printing technology of a general binder jet method,
2 is a view showing a 3D printing apparatus according to an embodiment of the present invention,
3 is a view showing a process of performing 3D printing using a 3D printing apparatus according to an embodiment of the present invention;
4 and 5 are views for explaining the process of deriving the pore volume of the n-layer to which the powder is supplied according to an embodiment of the present invention;
6 is a view for explaining a process of deriving the pore volume of the n-layer to which the powder is supplied according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those of ordinary skill in the art will be completely It is provided to inform you. In the drawings, like reference numerals refer to like elements.

2 is a diagram showing a 3D printing apparatus according to an embodiment of the present invention, and FIG. 3 is a diagram showing a process of performing 3D printing using the 3D printing apparatus according to an embodiment of the present invention.

As shown in FIG. 2 , the 3D printing apparatus according to an embodiment of the present invention is a 3D printing apparatus that prints a powder, which is a material of an output, in a binder jet method, and provides an output space in which the powder P is supplied and output. a case 10 and; a building plate 20 arranged to be raised and lowered in the output space of the case 10; It is disposed on the upper surface of the building plate 20 and includes a measuring plate 30 for measuring the mass of the powder (P) supplied to the output space.

And, a powder coater 40 disposed on the upper portion of the case 10 to flatten the powder (P) supplied to the output space of the case 10; a binder spraying means 50 disposed on the case 10 and spraying the binder B in a designed shape and amount to the powder P supplied to the output space of the case 10; It further includes a binder curing means 60 disposed on the upper portion of the case 10 to expose the curing source to the binder (B) to cure the binder (B).

At this time, the case 10, the building plate 20, the powder coater 40, the binder spraying means 50, and the binder curing means 60 are the same as the configuration of a general binder jet type 3D printing device or similarly applied. In addition, the case 10, the building plate 20, the powder coater 40, the binder spraying means 50 and the binder curing means 60 are not limited to a specific shape and method, but a binder jet technology It may be changed and implemented in various forms and methods that may be implemented.

For example, the case 10 is a means for providing an output space therein, and may be formed of a housing having an open top and a bottom.

So, the building plate 20 is disposed in the output space of the case 10 so as to be raised and lowered. At this time, the building plate 20 may be provided as a flat plate having a shape corresponding to the flat cross-sectional shape of the output space, and an elevating means may be provided at a lower portion thereof.

In addition, the powder coater 40 is provided in the form of a bar, and is disposed on the upper portion of the case 10 . Thus, the powder coater 40 moves in the horizontal direction in the upper region of the output space of the case 10 to flatten the upper surface of the powder supplied to the output space.

The binder spraying means 50 is a means for spraying the binder B according to a preset pattern and amount according to the shape of the output Pr, and is disposed on the upper portion of the case 10 like the powder coater 40 to the output space The binder (B) is sprayed with the powder (P) supplied to the output space while moving in the horizontal direction in the upper region of the

The binder curing means 60 is disposed on the upper portion of the case 10 like the powder coater 40 and the binder spraying means 50 and is moved in the horizontal direction in the upper region of the output space and the binder (B) sprayed into the output space. to provide a curing source. In this case, various sources such as infrared (IR) and ultraviolet (UV) may be applied as the curing source.

Meanwhile, in this embodiment, the mass of the powder (P) supplied to the building plate 20 is measured in real time to determine the injection amount of the binder (B), so that the mass of the powder (P) supplied to the output space is measured A plate 30 is provided.

The measuring plate 30 is disposed on the upper surface of the building plate 20 and is a means for measuring the mass of the powder supplied to the output space, and various measuring means for measuring the mass may be applied.

For example, the measuring plate 30 may be a precision scale in the form of a flat plate.

And, in this embodiment, the pore volume of the area to which the powder P is supplied is calculated using the mass value of the powder P measured in real time by the measuring plate 30, and the binder is sprayed according to the calculated pore volume. A control unit for adjusting the amount of the binder (B) sprayed to the powder (P) in the means (50) is further provided.

At this time, the control unit calculates the packing density of the supplied powder (P) using the measured mass value of the powder (P), and calculates the pore volume of the region to which the powder is supplied using the calculated packing density.

Therefore, the controller compares the amount of the binder (B) determined in real time with the amount of the initially set binder to derive a correction amount, and corrects the initially set amount of the binder (B) in real time according to the derived correction amount.

On the other hand, in the present invention, it is possible to derive a more accurate amount of the binder (B) by measuring the mass of each area of the powder supplied to the building plate 20 for each area.

To this end, the measurement plate 30 is provided so as to measure the mass of the powder (P) for each region divided by region and supplied to the output space.

For example, the measuring plate 30 provided in the form of a flat plate is divided into predetermined regions, and the measuring plate 30 is provided so that the mass can be individually measured in each of the divided regions. In other words, it will be possible to implement the measuring plates 31 to 36 by dividing the plate shape into a plurality of pieces and placing a precision low rate for each divided area.

A method of 3D printing using the 3D printing apparatus configured as described above will be described.

The 3D printing method according to an embodiment of the present invention is a 3D printing method of printing a powder, which is a material for an output, using a binder jet method.

For 3D printing, powder is first supplied to the printing space. (Powder supply step)

In the powder supply step, the powder (P) is supplied to the output space of the case (10) by using a powder supply means for supplying the powder (P) to the output space of the case (10) provided separately. Therefore, the powder P is sufficiently supplied to the upper surface of the building plate 20 provided with the measuring plate 30 .

In this case, the powder P used may be variously selected and applied according to the output Pr. For example, as the powder, sand, ceramic powder, metal powder, plastic, wood particles, fiber material, cellulose and lactose powder, etc. may be selectively used.

Then, as shown in Fig. 3 (a), using the powder coater 40, the supplied powder is arranged flat to form an n-layer. (Layer forming step)

At this time, the height of the n-floor is determined according to the position of the building plate 20 .

Then, the measurement plate 30 is operated to measure the mass value of the n-layer in real time. (Mass measurement step)

At this time, the total mass of the powder P may be measured for the n-layer formed in the upper region of the building plate 20 , but the n-layer may be partitioned for each region and the mass for each region may be measured separately.

On the other hand, when the mass value of the n-layer is measured, the amount of the binder (B) sprayed to the n-layer is determined using the measured mass value of the powder (P). (Binder amount determination step)

The binder amount determining step is a step of calculating the pore volume inside the n-layer to which the powder (P) is supplied by using the measured mass value of the n-layer, and determining the amount of the binder (B) in the calculated pore volume.

Before determining the amount of the binder (B), the amount of the binder (B) is initially set using the theoretical density of the powder (P) supplied to form the n-layer.

On the other hand, by using the set height of the n-floor and the area of the building plate 20 to which the powder P is supplied, the total volume of the n-floor can be derived. And, by using the mass value of the n-layer measured in real time and the theoretical density of the powder P, the volume of the powder occupied by the powder P among the total volume of the n-layer is calculated. So, the difference between the total volume of the n-layer and the real-time calculated volume of the powder P becomes the pore volume of the n-layer.

When the pore volume is calculated in this way, it is possible to determine the amount of the binder (B) to be sprayed on the area corresponding to the output (Pr) in the n-layer using this.

So, a correction amount is derived by comparing the amount of the binder (B) determined in real time with the amount of the initially set binder (B), and the amount of the initially set binder (B) is corrected according to the derived correction amount.

If the amount of the binder (B) is corrected and determined in real time in this way, the amount of the binder (B) determined by using the binder spraying means 50 as shown in FIG. to the n-layer with

And, as shown in FIG. 3(c), using the binder curing means 60, a curing source is irradiated to the binder B sprayed on the n-layer, and the binder is cured. (curing step)

So, by curing the binder (B) sprayed on the n-layer, the first region (P+B) mixed with the powder and the binder (B) is formed as an output (Pr). At this time, the region in which the binder (B) is not mixed among the n-layer remains as the second region Pl maintained in a powder state.

If the first region P+B is formed as a part of the output Pr, the building plate 20 is lowered by an n-layer thickness as shown in FIG. 3D.

Then, the n+1 layer is formed by supplying the powder (P) to the upper portion of the n-layer.

When the n+1 layer is formed in this way, the above process is sequentially repeated to obtain an output Pr having a desired shape.

If the above process is repeated to obtain an output Pr with a desired shape, the output Pr is unloaded from the building plate 20, and the second region Pl remaining around the output Pr is removed. to complete the output of the output Pr.

Next, a process of determining the injection amount of the binder by deriving the pore volume of the n-layer to which the powder is supplied will be described with reference to the drawings.

4 and 5 are views for explaining a process of deriving the pore volume of the n-layer to which the powder is supplied according to an embodiment of the present invention, and FIG. 6 is the n-layer to which the powder is supplied according to another embodiment of the present invention. It is a diagram explaining the process of deriving the pore volume of

As shown in Fig. 4, the area of the building plate forming the n-layer is 300*300 mm, and the height of the n-layer is 0.5 mm.

At this time, the powder was formed by mixing the first powder (P1) having a particle size of 7 μm and the second powder (P2) having a particle size of 2.8 μm to form an n-layer. At this time, the first powder (P1) and the second powder (P2) are both SUS304 bimodal powder, and the density is 7.90 g/cm 3 . And, the binder (B) uses monobutyl ether (EGBE), isopropanol, ethylene glycol. At this time, the area of the n-layer to be sprayed with the binder (B) was designed to be 100 * 100 mm.

If the total mass of the n-layer measured in real time is measured to be 315 g, the packing density of the n-layer is 0.797. That is, it can be derived that the pores in which the powder is not located in the n-layer are 0.203, that is, the porosity of the n-layer is 20.3% with respect to the total volume.

Therefore, the amount of the binder (B) to be sprayed on the n-layer may be determined by multiplying the porosity by the volume of the region to which the binder (B) is to be sprayed.

Therefore, as 100mm*100mm*0.5mm*0.203 = 1.015, it can be derived that the amount of the binder (B) to be sprayed to the n-layer is 1.015 cm 3 (ml).

Next, as shown in FIG. 5 , the area of the building plate forming the n-layer was 300*300 mm, and the height of the n-layer was 0.5 mm, and the same was applied in the case of FIG. 4 .

Also, in the case of FIG. 4, the n-layer was formed by mixing the first powder P1 having a particle size of 7 μm and the second powder P2 having a particle size of 2.8 μm in the same manner as in the case of FIG. 4, and the first powder P1 and the first powder P1 Both powders (P2) are SUS304 bimodal powders, and the density is 7.90 g/cm 3 . And, the binder (B) uses monobutyl ether (EGBE), isopropanol, ethylene glycol. And the area of the n-layer to which the binder (B) is to be sprayed was designed to be 100 * 100 mm.

However, in FIG. 5 , the total mass of the n-layer measured in real time was measured to be 175.5 g. Therefore, the packing density of the n-layer becomes 0.494. That is, it can be derived that the pores in which the powder is not located in the n-layer are 0.506, that is, the porosity of the n-layer is 50.6% of the total volume.

Accordingly, the amount of the binder (B) to be sprayed on the n-layer may be determined by multiplying the porosity by the volume of the region to which the binder (B) is to be sprayed.

Therefore, as 100mm*100mm*0.5mm*0.506 = 2.53, it can be derived that the amount of the binder (B) to be sprayed on the n-layer is 2.53 ㎤ (ml).

As can be seen in the case of FIGS. 4 and 5, it can be confirmed that the injection amount of the binder can be accurately determined using the mass value of the n-layer measured in real time regardless of the size of the powder.

Next, as shown in FIG. 6 , a process of dividing the mass of the n-layer for each region and determining the amount of the binder sprayed for each region will be described.

As shown in FIG. 6 , the area of the building plate forming the n-layer was 300*300 mm, and the height of the n-layer was 0.5 mm, and the same was applied in the case of FIGS. 4 and 5 .

Also, in the case of FIGS. 4 and 5, the n-layer was formed by mixing the first powder P1 having a particle size of 7 μm and the second powder P2 having a particle size of 2.8 μm in the same manner as in FIGS. 4 and 5, and the first powder P1 ) and the second powder (P2) are both SUS304 bimodal powder, and the density is 7.90 g/cm 3 . And, the binder (B) uses monobutyl ether (EGBE), isopropanol, ethylene glycol. And the area of the n-layer to which the binder (B) should be sprayed was designed to be 100 * 100 mm.

However, in FIG. 6, the mass of the n-layer was measured for each region using the measurement plates 31 to 36 divided into six, and as a result, 29.1284 g, 28.8425 g, 30.1214 g, 29.7235 g, 29.8442 g, 30.1415 g, respectively. was measured as Accordingly, the packing density of the n-layer becomes 0.491, 0.486, 0.508, 0.501, 0.503, and 0.508 for each region, respectively. That is, it can be derived that the ratio of pores in which the powder is not located in the n-layer is 0.509, 0.514, 0.492, 0.499, 0.497, and 0.492, respectively.

Accordingly, the amount of the binder (B) to be sprayed into the n-layer divided for each area may be determined by multiplying the porosity by the volume of the area to which the binder (B) is to be sprayed.

Accordingly, it can be derived that the amount of the binder (B) to be sprayed for each area is 0.41 cm 3 (ml), 0.405 ml, 0.423 ml, 0.417 ml, 0.419 ml, 0.423 ml.

Although the present invention has been described with reference to the accompanying drawings and the above-described preferred embodiments, the present invention is not limited thereto, and is defined by the following claims. Accordingly, those of ordinary skill in the art can variously change and modify the present invention within the scope without departing from the spirit of the claims to be described later.

10: case 20: building plate
30: measuring plate 40: powder coater
50: binder spraying means 60: binder curing means

Claims (11)

A 3D printing device for printing a powder, which is a material for an output, in a binder jet method, comprising:
a case providing an output space through which the powder is supplied and output;
a building plate arranged to be raised and lowered in the output space of the case;
3D printing apparatus including a measuring plate disposed on the upper surface of the building plate to measure the mass of the powder supplied to the output space.
The method according to claim 1,
a powder coater disposed on the upper portion of the case to flatten the powder supplied to the output space of the case;
a binder spraying means disposed on the upper portion of the case and spraying the binder in a designed pattern and amount to the powder supplied to the output space of the case;
The 3D printing apparatus further comprising a binder curing means disposed on the upper portion of the case to harden the binder by exposing the curing source to the binder.
3. The method according to claim 2,
A control unit for calculating the pore volume of the region to which the powder is supplied is calculated using the mass value of the powder measured by the measuring plate, and adjusting the amount of the binder sprayed from the binder spraying means to the powder according to the calculated pore volume. 3D printing apparatus, characterized in that.
4. The method according to claim 3,
The control unit calculates the packing density of the supplied powder by using the measured mass value of the powder, and 3D printing apparatus, characterized in that it calculates the pore volume of the powder supplied area using the calculated packing density.
The method according to claim 1,
3D printing apparatus, characterized in that the measurement plate is partitioned for each area and measures the mass of each area of the powder supplied to the output space.
A 3D printing method for printing a powder, which is a material for an output, in a binder jet method, comprising:
a powder supply step of supplying the powder to the output space;
A layer forming step of flattening the supplied powder using a powder coater to form an n-layer;
a mass measurement step of measuring the mass value of the n-layer;
a binder amount determining step of determining the amount of the binder sprayed to the n-layer using the measured mass value of the powder;
a spraying step of spraying the determined amount of the binder on the n-layer in a pattern designed according to the shape of the output;
A 3D printing method comprising a curing step of curing the binder by irradiating a curing source to the binder sprayed on the n-layer.
7. The method of claim 6,
The mass measurement step is a 3D printing method, characterized in that the n-layer is partitioned for each region and the mass for each region is separately measured.
7. The method of claim 6,
The binder amount determining step is a 3D printing method, characterized in that by calculating the pore volume inside the n-layer to which the powder is supplied by using the measured mass value of the n-layer, and determining the amount of the binder in the calculated pore volume.
9. The method of claim 8,
The binder amount determination step,
Calculate the volume of the powder supplied to the n-layer using the theoretical density of the powder supplied to the n-layer and the measured mass value of the n-layer, and compare the calculated volume of the powder with the total volume of the n-layer. 3D printing method, characterized in that calculating the pore volume.
9. The method of claim 8,
The binder amount determination step,
3D printing method, characterized in that by comparing the amount of the binder determined in real time with the amount of the initially set binder, and deriving a correction amount, and correcting the initially set amount of the binder according to the derived correction amount.
7. The method of claim 6,
3D printing method, characterized in that after the curing step, sequentially repeating the powder supply step to the curing step a plurality of times with respect to the upper portion of the n-layer.

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