KR20200110191A - A three dimensional printing apparatus using ceramic material - Google Patents

Abstract

The present invention relates to a method for controlling a three-dimensional printing apparatus using a stick-shaped ceramic material. The method includes the steps of: allowing a variable support unit to slide along the longitudinal direction of a precise ball screw-based actuator; allowing a material stick compressing bar fixed to one side of the variable support unit and controlled in movement in a nanometer unit to move vertically in the Z-axis direction by the actuator; and pressurizing a material stick mounted to a melting nozzle by using the material stick compressing bar, while ejecting the material in a molten state by a melting unit for melting one side of the material stick, wherein the material stick is a stick formed in a bar-like shape from a composition including metal and ceramic powder.

Description

3D printing device using ceramic material {A THREE DIMENSIONAL PRINTING APPARATUS USING CERAMIC MATERIAL}

The present invention relates to a 3D printing apparatus using a ceramic material, and more particularly, a 3D printing apparatus using a ceramic material with improved product reliability by performing 3D printing by finely adjusting the extrusion amount of a high strength material stick. About.

A 3D (3-Dimension) printing device is an equipment that uses 3D data on an object to be printed to form a shape in 3D so that it has the same or similar shape as the object. The use of 3D printing is expanding in various fields. In the past, these 3D printing devices have been used for purposes such as modeling and sample production before mass production, but in recent years, as a technological foundation that can be used for molding mass-producible products centering on multi-species small quantity products has been established, a number of In addition to the automotive field composed of parts, it is used by many manufacturers to make various models such as medical human body models and household products such as toothbrushes and razors.

The product molding method of the 3D printing device is the so-called additive type, in which the object is molded into a two-dimensional planar shape and then melted and attached to form a shape by laminating it in three dimensions, and the so-called additive type, which cuts the raw material mass as if carving it. There is a cutting type. In addition, as a type of additive type, a wire or filament made of thermoplastic plastic is supplied through a supply reel and a transfer roll, and the supplied filament is mounted on a three-dimensional transfer mechanism that is positioned in three directions in XYZ relative to the worktable. There is a filament melt lamination molding method in which a product having a three-dimensional shape of an object to be printed is formed by repeatedly laminating a print layer (two-dimensional planar form) on a base plate by melting and discharging it from a nozzle.

However, the conventional three-dimensional molding method, as described above, uses a plastic raw material, so there is a limit that it is not joined to form steel products such as metal parts that require high strength and high precision.

The problem to be solved by the present invention is a three-dimensional printing device using a stick-type metal and ceramic material with improved productivity by extruding a high-strength material stick made of a composition containing metal and ceramic powder as a raw material, thereby improving the working speed, and precise extrusion control thereof. To provide a way.

Another problem to be solved by the present invention is a 3D printing apparatus using stick-type metal and ceramic materials with improved precision by controlling the movement of the material stick compression rod in units of several nanometers (nm) using a precision ball screw-based actuator. And a precise extrusion control method thereof.

Another problem to be solved by the present invention is to control the pressure of the material stick compression rod to finely adjust the amount of extrusion of the material stick, thereby minimizing cracks when stacking a printed layer and improving product reliability. It is to provide a three-dimensional printing apparatus using a material and a precise extrusion control method thereof.

The problems of the present invention are not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

In order to solve the above-described problems, a three-dimensional printing apparatus using a stick-type metal and ceramic material according to an embodiment of the present invention includes: a variable support capable of slidably moving along a length direction of an actuator; A material stick compression rod whose movement is controlled by an actuator in units of nanometers, is fixed to a lower side of the variable support, extends downward by a predetermined length, and presses the material stick inserted into the material barrel mounted on the melting nozzle; And a melting unit disposed on the top of the melting nozzle to melt one end of the material stick, and the material stick pressurized by the material stick compression rod is applied to the outer peripheral surface of the three-dimensional object to be extruded so that a certain amount of material stick is extruded per unit area. It controls the speed of the molten nozzle moving along and the amount of extrusion of the material stick, and the compression speed of the material stick in the curved section of the outer peripheral surface is set slower than the compression speed of the material stick in the straight section of the outer peripheral surface. Accordingly, by extruding a bar-shaped material stick made of a composition containing metal and ceramic powder as a raw material, it is possible to increase the working speed and improve fishiness.

(여기서, d_e는 재료스틱의 지름, l_e는 압출 거리, d_s는 압출된 재료의 폭, l_s는 압출된 재료의 길이를 나타냄)According to another feature of the present invention, the extrusion amount can be calculated by the following equation. [Equation]

(Where d _e is the diameter of the material stick, l _e is the extrusion distance, d _s is the width of the extruded material, and l _s is the length of the extruded material)

According to another feature of the present invention, it may further include a heat dissipation unit that prevents the heat generated in the melting unit from moving upward.

According to another feature of the present invention, the material stick includes a composition containing metal and ceramic powder composed of a metal and ceramic powder and a polymer binder, and the composition containing metal and ceramic powder is kneaded at a temperature of 160°C or higher to form a bar. The material stick manufactured in the form can be mounted on the melting nozzle.

According to another feature of the present invention, the metal and ceramic powder may be an austenitic stainless metal and ceramic powder having a steel composition of SUS-304L or SUS-316L.

According to another feature of the present invention, the polymeric binder may include a binder, a plasticizer, and a lubricant.

According to another feature of the present invention, the material stick. One side located in the direction of the melting nozzle by the melting part may be in a semi-solid state and the other side may be in a solid state.

According to another feature of the present invention, when the extrusion head of the 3D printing device is moved to the X axis or Y axis without extruding the material stick by the material stick compression rod, the material stick compression rod is retracted. The position of the material stick compression rod can be adjusted to move upward, and the material stick compression rod can be adjusted so that the material stick moves more than the distance moved inside the melting nozzle.

(여기서, d_e는 재료스틱의 지름, l_e는 압출 거리, d_s는 압출된 재료의 폭, l_s는 압출된 재료의 길이를 나타냄) 이에, 재료스틱압축봉의 압력을 제어하여 재료스틱의 압출량을 미세하게 조정함으로써 프린트 층 적층 시 크랙을 최소화하고 제품의 신뢰성을 향상시킬 수 있다.In order to solve the above-described problems, the precise extrusion control method of a three-dimensional printing device using a stick-type metal and ceramic material according to another embodiment of the present invention is a variable in which movement is controlled in nanometer units by an actuator. Pressing the material stick inserted into the material barrel mounted on the melting nozzle by the material stick compression rod fixed on the lower side of the variable support part as the support part slides along the longitudinal direction of the actuator; Melting by heating one end of the material stick mounted on the melting nozzle by the melting unit; And extruding the molten material stick in the lower direction of the melting nozzle. And retracting the material stick compression rod after extruding the material stick, wherein the extrusion amount of the material stick is calculated based on the following equation. [Equation]

(Here, d _e is the diameter of the material stick, l _e is the extrusion distance, d _s is the width of the extruded material, and l _s is the length of the extruded material.) Therefore, by controlling the pressure of the material stick compression rod, By fine-tuning the amount of extrusion, it is possible to minimize cracks and improve product reliability when laminating the print layer.

According to another feature of the present invention, the step of retracting the material stick compression rod after extruding the material stick is performed by moving the extrusion head of the 3D printing device in the X-axis or Y-axis. Release pressure,

As the pressure of the material stick compression rod is released, the distance the material stick compression rod moves upward can be adjusted to be longer than the distance the material stick moves inside the melting nozzle.

Details of other embodiments are included in the detailed description and drawings.

In the present invention, by using a bar-shaped material stick using a composition containing metal and ceramic powder as a raw material for 3D printing, it is possible to increase work speed and improve productivity.

In addition, the present invention can improve the quality of the outer periphery of a three-dimensional structure by controlling the extrusion amount of the material stick compression rod in units of several nanometers (nm) using an actuator.

In addition, according to the present invention, by controlling the pressure of the material stick compression rod to finely adjust the extrusion amount of the material stick, it is possible to minimize cracks and improve product reliability when laminating a printed layer.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a diagram showing a three-dimensional printing process for performing three-dimensional printing using a composition containing metal and ceramic powders according to the present invention.
2 is a cross-sectional view showing an extrusion head of a 3D printing apparatus according to an embodiment of the present invention.
3 is a flowchart illustrating a 3D printing method according to an embodiment of the present invention.
4A to 4B are views for explaining an extrusion process of a 3D printing apparatus according to an embodiment of the present invention.
5 is a diagram for explaining a method of calculating an extrusion amount of a material stick according to an embodiment of the present invention.
6 is a view for explaining a process of determining the presence or absence of extrusion of the 3D printing apparatus according to an embodiment of the present invention.
7 is a view for explaining a heat dissipation part of the 3D printing apparatus according to an embodiment of the present invention.
8 is a view for explaining a retraction process of a 3D printing apparatus according to an embodiment of the present invention.
9 is a view showing to compare the comparative example of the present invention and the example.

The following content merely illustrates the principle of the invention. Therefore, although those skilled in the art may implement the principles of the invention and invent various devices included in the concept and scope of the invention, although not clearly described or illustrated herein. In addition, it should be understood that all conditional terms and examples listed in this specification are, in principle, expressly intended only for the purpose of making the concept of the invention understood, and are not limited to the embodiments and states specifically listed as such. do.

In addition, in the following description, ordinal expressions such as first, second, etc. are intended to describe objects that are equivalent and independent of each other, and in the order of main/sub or master/slave It should be understood as meaningless.

The above-described objects, features, and advantages will become more apparent through the following detailed description in connection with the accompanying drawings, and accordingly, a person of ordinary skill in the technical field to which the invention pertains will be able to easily implement the technical idea of the invention. .

Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, and as a person skilled in the art can fully understand, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other. It may be possible to do it together in a related relationship.

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

Hereinafter, a configuration and operation of a 3D printing apparatus will be described with reference to FIGS. 1 to 2.

1 is a diagram showing a three-dimensional printing process for performing three-dimensional printing using a composition containing metal and ceramic powders according to the present invention. 2 is a cross-sectional view showing an extrusion head of a 3D printing apparatus according to an embodiment of the present invention.

Referring to FIG. 1, the present invention uses a metal and ceramic powder-containing composition 30 in which a metal or ceramic powder 20a and a polymeric binder 20b are homogeneously kneaded at a high temperature through a kneading machine 500. It is manufactured with a material stick 151 having a (Bar) shape.

The metal and ceramic powder-containing composition 30 prepared in this way is laminated in a three-dimensional printing method and supplied to the melting nozzle 172 of the extrusion head 100 as a feedstock used to manufacture the steel product 50. do. Here, the melting unit 171 and the material stick are compressed so that the material stick 151 made of the composition 30 containing metal and ceramic powder in a bar shape can be smoothly supplied to the melting nozzle 172 of the extrusion head 100. It is preferably melted and pressurized by the rod 140 to be supplied to the melting nozzle 172.

The composition 30 containing metal and ceramic powder supplied to the melting nozzle 172 is discharged to the surface of the base plate 200 in a manner similar to the hot melt adhesive gun, so that the print layer is formed in a three-dimensional shape of the object to be printed. By successively stacking, a semi-finished product (40) is formed.

In the semi-finished product 40 formed in this way, the polymeric binder component is removed from the degreasing unit 300 by a solvent and hot degreasing method, sintered at a high temperature in the sintering unit 400, and then cooled to room temperature to form the final steel. (製) The process of extracting into product 50 is made.

Composition containing metal and ceramic powder

In the present invention, the metal and ceramic powder 20a constituting the composition 30 containing metal and ceramic powder is made of austenitic stainless steel having a steel composition of SUS-304L or SUS-316L. Used metal and ceramic powder. Here, the austenitic stainless steel is also called Cr-Ni stainless steel, and is obtained by adding Cr and Ni to Fe. In other words, the main components of the austenitic stainless steel are composed of Fe, Cr, and Ni, and other than that, various additives shown in Table 1 below may be included. Table 1 below shows a preferred example of austenitic stainless steel, which is a component of metal and ceramic powder, used to prepare a composition containing metal and ceramic powder for 3D printing in the present invention, but is not limited thereto.

ingredient C Si Mn Cr Ni Mo P S Etc Composition 1 (% by mass) 0.03
Below 1.0
Below 1.0
Below 18 to 20 10 to 12 0.2
Below 0.03
Below 0.03
Below Balance Fe and
Other inevitable impurities Composition 2 (% by mass) 0.03
Below 1.0
Below 1.5
Below 16 to 18 11 to 14 2 to 3 0.03
Below 0.03
Below Balance Fe and
Other inevitable impurities

Carbon (C): Less than 0.03% by weight Carbon (C) reacts with chromium (Cr) added to improve corrosion resistance, and precipitates as chromium (Cr) carbide at the grain boundary. May cause a decrease in Accordingly, the smaller the content of carbon (C) is, the more preferable it is, and when the content of carbon (C) is 0.03% by weight or less, the corrosion resistance is not significantly reduced. Therefore, the content of carbon (C) is preferably 0.03% by weight or less.

Silicon (Si): 1.0% by weight or less

Silicon (Si) is an effective element for deoxidation, and is added in the solvent stage. However, if excessively contained, the steel product extracted after degreasing and sintering may harden (causes hardening of the stainless steel sheet), resulting in a decrease in ductility (decrease ductility), so the content of silicon (Si) is 1.0% by weight or less is preferable.

Manganese (Mn): 1.5% by weight or less

Manganese (Mn) has the effect of reducing sulfur (S) dissolved in stainless steel by combining with sulfur (S) inevitably mixed, and suppresses grain boundary segregation of sulfur (S). of sulfur at the grain boundary), which is effective in preventing cracking of the steel product extracted after degreasing and sintering (prevents cracking of the steel sheet during hot rolling). However, even if it is added in excess of 1.5% by weight, there is little increase in the effect to be added. Rather, it causes an increase in cost by adding excessively. Therefore, the content of manganese (Mn) is preferably 1.5% by weight or less.

Nickel (Ni): 10 to 14% by weight

Nickel (Ni) is an element that stabilizes the austenite phase, and is added when producing an austenitic stainless steel. In that case, when the content of nickel (Ni) exceeds 14% by weight, excessive consumption of nickel (Ni) causes an increase in cost. Therefore, the content of nickel (Ni) is preferably 14% by weight or less.

Molybdenum (Mo): 3% by weight or less

Molybdenum (Mo) is an effective element in suppressing local corrosion such as crack corrosion of stainless steel. Therefore, when a steel product is used in a harsh environment, it is effective to add molybdenum (Mo). However, if it is added in excess of 3% by weight, the stainless steel may become embrittlement, resulting in a decrease in productivity, and excessive consumption of molybdenum (Mo) causes an increase in cost. Therefore, the content of molybdenum (Mo) is preferably 3% by weight or less.

Phosphorus (P): 0.03% by weight or less

Since phosphorus (P) causes a decrease in ductility, a lower one is preferable, but if it is 0.03% by weight or less, the ductility does not significantly decrease. Therefore, the content of phosphorus (P) is preferably 0.03% by weight or less.

Sulfur (S): 0.03% by weight or less

Sulfur (S) is an element that reduces corrosion resistance by combining with manganese (Mn) to form manganese sulfide (MnS), and the lower one is preferable. If it is 0.03% by weight or less, corrosion resistance is not significantly reduced. Therefore, the content of sulfur (S) is preferably 0.03% by weight or less.

The balance is iron (Fe) and unavoidable impurities.

In the present invention, it is preferable to use a metal and ceramic powder having a particle diameter (D50) of 9.5 to 11 μm in the austenitic stainless metal and ceramic powder having a composition and content ratio of composition 1 or composition 2 in Table 1. . In addition, in order to increase the density of the final finished steel product, reduce the polymeric binder content, and maintain a uniform shrinkage during sintering, austenite It is preferable to use metal and ceramic powder powdered into a spherical shape as the stainless steel metal and ceramic powder. The method of manufacturing austenitic stainless metal and ceramic powder is to scatter a liquefied (superheated) austenitic stainless metal stream into fine droplets, and then a spherical particle diameter (D50) of 9.5 ~ 11㎛. It can be produced by a spray process of cooling with solid particles.

The austenitic stainless metal and ceramic powder composed of the components and content ratio of Composition 1 or Composition 2 and spherically pulverized to a particle diameter (D50) of 9.5 to 11 μm are kneaded with a polymer binder including a binder, a plasticizer, and a lubricant. In this case, the Osnite stainless metal and ceramic powder may be included in an amount of 90.0 to 94.0 wt%, and a polymeric binder may be included in an amount of 6.0 to 10.0 wt% with respect to the total weight of the metal and ceramic powder-containing composition. If the Osnite stainless metal and ceramic powder is less than 90.0% by weight of the total weight of the metal and ceramic powder-containing composition, a large amount of polymeric binder is removed by the degreasing process described below, so that the shape of the semi-finished product 40 is to be printed. If it is not maintained in a three-dimensional shape and exceeds 94.0% by weight, a small amount of a polymeric binder is added, and it is difficult to secure cohesive strength as a feedstock for 3D printing.

The binder as the main chain (backbone) binder to be added to ensure the cohesion required in the three-dimensional printing process, the lower the bonding force between the spherical powdered an austenitic stainless steel and ceramic powder, polystyrene (Polystyrene), Polyethylene (Polyethylene), PP (polypropylene), ethylene vinyl acetate (Ethylene-vinylacetate), ethylene ethyl acrylate (Ethylene-ethylacrylate), methyl methacrylate (Methal-methacrylate), at least one selected from the group consisting of butyl methacrylate (Butyl-methacrylate) Copolymers may be included. In particular, a polyethylene copolymer is preferable as a binder added to the Osnite stainless metal and ceramic powder. The polyethylene copolymer is removed at a high temperature, while the steel product that has undergone a hot degreasing process maintains its shape. The polyethylene copolymer is preferably contained in 3 to 5% by weight based on the total weight of the composition containing metal and ceramic powder.

A plasticizer is an organic material that is added to the austenitic stainless metal and ceramic powder and agglomerated composition by bonding of a binder to facilitate molding and processing during 3D printing.Microcrystalline wax, paraffin wax, Montan wax or the like may be used. In particular, in the present invention, as a plasticizer, paraffin wax, which can increase ductility by lowering the bonding force between polymeric binders even at a relatively low temperature, is added. The paraffin wax is preferably contained in an amount of 2.5 to 3.5% by weight based on the total weight of the composition containing metal and ceramic powder.

Lubricant is a component added so that the composition containing metal and ceramic powder is melted in the raw material feeder and then smoothly supplied to the extrusion head 100 via the supply guide pipe by improving the surface slippage during pressure injection. (Stearic acid), oleic acid, palmitic acid, linolenic acid, and the like may be used, but stearic acid is added in the present invention. The stearic acid is preferably contained in 0.5 to 1.5% by weight based on the total weight of the composition containing metal and ceramic powder.

1 hour at a high temperature of 170°C, which is a temperature at which the polyethylene copolymer, a binder contained in the polymer binder, and the austenitic stainless metal and ceramic powder having the components and content ratio of the above-described composition 1 or composition 2 are completely melted After kneading uniformly during, it is cooled to room temperature. The mixture cooled after heating and kneading is pulverized in a pulverizer or a pelletizer and granulated into pellets having a predetermined particle size, thereby finally producing a composition containing metal and ceramic powder.

Configuration of 3D printing device

The three-dimensional printing apparatus of the present invention is a printer based on a three-axis (X, Y, Z) motion. As shown in FIG. 2, the extrusion head 100 of the three-dimensional printing apparatus includes a material stick compression rod 140 A servo motor 110 that controls ), a variable support 130 that can slide up and down along the longitudinal direction of the actuator 120, and the actuator 120 control the movement in nanometer units, and the variable support ( A material stick compression rod 140 that presses the material stick 151 inserted into the material barrel 150 that is fixed to the lower side of 130 and extends a certain length in the lower direction, It is disposed on the top of the material barrel 150 and the melting nozzle 172 and includes a melting portion 171 for melting one end of the material stick 150.

The servo motor 110 is a configuration that precisely controls the material stick compression rod 140 using the actuator 120, and receives the position value from the computing device, and provides the variable support 130 fixed to the actuator 120. Linear motion up and down. Meanwhile, in the present invention, the servo motor 110 may be a stepping motor.

The variable support 130 is a component in which movement is controlled by the actuator 120 in nanometers (nm), and controls the movement of the material stick compression rod 140 fixed to the lower side. As will be described later, as the variable support 130 vertically moves in the Z-axis direction, the material stick compression rod 140 fixed to the variable support 130 vertically moves, and the material stick inserted into the material barrel 150 located below it ( 151) can be pressed. Although the material stick 151 is not shown in FIG. 2, it is preferable to be understood as a configuration inserted into the material barrel 151 as shown in FIG. 7 to be described later.

A melting nozzle 172 is disposed at the lower end of the material stick compression rod 140 to narrow the width toward the lower end. Here, the melting nozzle 172 is a nozzle through which the molten material stick 151 is discharged, and the material stick 151 melted through the melting nozzle 172 is stacked on the base plate 200 one layer at a time. At this time, as the material stick 151 discharged to the base plate 200 is stacked, the air cylinder 180 may move the melting nozzle 172 in the Z-axis direction. In the present specification, the material stick 151 extruded by pressing the material stick 151 inserted into the material barrel 150 mounted on the melting nozzle 172 by the material stick compression rod 140 is It is preferably understood that the material in a molten state has been discharged.

The upper end of the melting nozzle 172, that is, between the melting nozzle 172 and the material barrel 150, a melting unit 171 for heating and melting one end of the material stick 151 mounted on the melting nozzle 172 Is placed. In more detail, referring to FIG. 7, the lower end of the material stick 151 is heated by the melting unit 171 located at the upper end of the melting nozzle 172 so that one side of the material stick 151 is in a semisolid-state state. ), and the other side may be in a solid-state. In FIG. 7, it is shown that the lower side is in a semi-solid state and the upper side is in a solid state based on the dotted line indicated on the material stick 151, but the heating region of the melting portion 171 may be more local than that illustrated in FIG. 7. That is, a region in a semi-solid state may be smaller than a region in a solid state.

In addition, a heat dissipation unit 160 is further disposed at the upper end of the melting unit 171 to prevent heat generated from the melting unit from moving upward. Here, the radiating part 160 may further include a radiating fan and a radiating plate. Details related to the heat dissipation unit 160 will be described later with reference to FIG. 7.

Hereinafter, a 3D printing method according to an embodiment of the present invention will be described with reference to FIGS. 3 to 8.

3 is a flowchart illustrating a 3D printing method according to an embodiment of the present invention. 4A to 4B are views for explaining an extrusion process of a 3D printing apparatus according to an embodiment of the present invention. 5 is a diagram for explaining a method of calculating an extrusion amount of a material stick according to an embodiment of the present invention. 6 is a view for explaining a process of determining the presence or absence of extrusion of the 3D printing apparatus according to an embodiment of the present invention. 7 is a view for explaining the heat dissipation unit 160 of the 3D printing apparatus according to an embodiment of the present invention. 8 is a diagram for explaining a retraction process of a 3D printing apparatus according to an embodiment of the present invention.

First, the movement of the variable support 130 is controlled in nanometer units by the actuator 120 (S310). Subsequently, as the variable support 130 moves vertically in the Z-axis direction by the actuator 120, the material stick compression rod 140 fixed to the lower side of the variable support 130 is mounted on the melting nozzle 172. The material stick 151 inserted in the 150 is pressed (S320). Subsequently, one end of the material stick 151 mounted on the melting nozzle 172 by the melting unit 171 is heated and melted (S330). Subsequently, the melted material stick 151 is extruded in the lower direction of the melting nozzle 172 (S340). Finally, after the melted material stick 151 is extruded, the material stick compression rod 140 is retracted (S350).

Referring to FIG. 4A, before the servo motor 110 receives the position value from the computing device, the variable support part 130 fixed to the actuator 120 does not move vertically in the Z-axis direction, so the material stick compression rod 140 The and material barrels 150 are disposed to be spaced apart from each other. That is, the state shown in FIG. 4A shows a state in which the material is not extruded from the extrusion head 100.

4B, the servo motor 110 receives the position value from the computing device and the variable support 130 fixed to the actuator 120 moves vertically in the Z-axis direction, and the material stick compression rod 140 Pressurize (151). At this time, the material stick 151 is mounted on the melting nozzle 172, and one end of the material stick 151 is heated and melted by the melting unit 171 located at the upper end of the melting nozzle 172. The material stick 151 is discharged to the melting nozzle 172 according to the pressure of the material stick compression rod 140. Thus, in the present invention, by checking the torque of the servo motor 110 in real time, the material stick compression rod 140 presses the material stick 151 so that the melted material stick 151 touches the melting nozzle 172. You can check whether it is being discharged through.

At this time, the relative extrusion amount of the melted material stick 151 is determined based on the extrusion distance of the melted material stick 151 and the printing distance of the discharged material, as shown in FIG. 5. In FIG. 5, Material represents the melted material stick 151, Structure represents the discharged material, and the amount of extrusion is calculated based on the following equation. In the present invention, the amount of extrusion is preferably defined as the distance at which the material stick compression rod 140 presses the material stick 151.

[Equation]

Here, d _e is the diameter of the melted material stick, l _e is the extrusion distance, d _s is the diameter of the discharged material, and l _s is the length of the extruded material.

Accordingly, the present invention can control the amount of extrusion of the material by adjusting the printing distance of the melting nozzle 172.

In addition, the present invention can check the torque applied to each of the X-axis, Y-axis, Z-axis, and E-axis of the material stick compression rod 140 in real time using the 3D Controls program (60, the self-developed program of the present invention). . For example, as shown in FIG. 6, when the E-axis of the material stick compression rod 140 generates about 5 to 20% of torque (based on a 100W servo motor), it may be determined that the material is discharged. At this time, the torque value may vary depending on the material.

Meanwhile, as shown in FIG. 7, when the material stick 151 is heated and melted by the melting unit 171, the heat of the melting unit 171 due to the characteristics of the material stick 151 containing metal and ceramic powder It can be conveyed over this. Accordingly, the heat transferred to the upper portion of the material stick 151 may melt the entire material stick 151, and in this case, the molten material stick 151 is the upper end of the material barrel 151 disposed at the edge. It can overflow through.

Therefore, in the present invention, by installing the heat dissipation unit 160 on the upper side of the melting unit 171 disposed on the melting nozzle 172 to design heat dissipation in the extrusion head 100, the material stick compression rod 140 is removed. It is possible to solve the problem that the material soars upside down toward the material stick compression rod 140 even during retraction.

Here, to explain in more detail about the retraction of the material stick compression rod 140, in order to extrude a relatively large diameter material stick (150, about 8 mm) with a small diameter nozzle (about 0.4 ~ 0.6mm) Great pressure is required. Therefore, as shown in FIG. 8, a considerable amount of pressure is maintained near the melting nozzle 172 inside the material barrel 150, and when the material is only moved in the X-axis or Y-axis without extruding the material, such A significant amount of pressure must be removed instantly. However, in this case, the melted material stick 151 rises within the material barrel 150 due to the pressure remaining inside the material barrel 150.

In other words, when the material stick compression rod 140 is retracted, as the pressure of the material stick compression rod 140 is released, the melted material stick 151 is an empty space where the pressure is released rather than exiting through the melting nozzle. As it is easier for the melted material stick 151 to rise, the molten material rises in the material barrel 150.

Accordingly, as the pressure of the material stick compression rod 140 is released when the material stick compression rod 140 is retracted, the molten material stick 151 rises to meet the material stick compression rod 140. . At this time, when the molten material stick 151 meets the material stick compression rod 140, the molten material stick 151 is exposed downward through the melting nozzle 172 to form a crack or improve the completeness of the structure. Can lower it.

Accordingly, in the step of retracting the material stick compression rod 140 (S350), the extrusion head 100 is only moved to the X-axis or Y-axis without extruding the material in the 3D printing device, and the material stick compression rod Relieve the pressure of 140.

Therefore, in the present invention, when performing the retraction process, the distance b that the material stick compression rod 140 moves in the upward direction is the material stick 151 moves in the upward direction within the material barrel 150. By adjusting the position of the material stick compression rod 140 to be longer than the distance (a), it is possible to prevent unnecessary material extrusion.

9 is a view showing to compare the comparative example of the present invention and the example.

9, 90a and 90b are 3D structures according to the comparative example, and 90c is a 3D structure according to the embodiment. In the case of the comparative example in which the amount of extrusion was not adjusted in the portion where the bending occurs as shown in 90a and 90b of FIG. 9, it can be seen that the outer periphery of the structure is unevenly stacked. On the other hand, in the case of the embodiment in which the amount of extrusion is adjusted in the portion where the bend occurs, as shown in 90c of FIG. 9, it can be seen that the structure is smoothly stacked without being bent.

Accordingly, the present invention can improve the precision of the 3D structure by controlling the movement of the material stick compression rod 140 in units of several nanometers (nm) using the actuator 120.

In addition, by controlling the pressure of the material stick compression rod 140 to finely adjust the amount of extrusion of the material stick 151, cracks during lamination of the printed layer may be minimized and reliability of the product may be improved.

In addition, by using a bar-shaped material stick 151 made of a composition containing metal and ceramic powder as a raw material for 3D printing, it is possible to increase the working speed and improve fishiness.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made without departing from the spirit of the present invention. . Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

20a: metal and ceramic powder 20b: polymer binder
30: composition containing metal and ceramic powder
40: semi-finished product 50: steel product
100: extrusion head 110: servo motor
120: actuator 130: variable support
140: material stick compression rod 150: material stick
151: material barrel 160: radiating part
170: nozzle part 171: melting part
172: melting nozzle 180: air cylinder
200: base plate 300: degreasing unit
400: sintering unit 500: kneader

Claims (8)

A variable support unit vertically moving in the Z-axis direction according to the production of a three-dimensional object; A material barrel disposed under the material stick compression rod to be spaced apart at a predetermined interval; And a material stick inserted in the material barrel and mounted on the melting nozzle,
The material stick is formed of a composition containing metal and ceramic powder in the form of a bar, and the metal and ceramic powder is an austenitic stainless metal and ceramic powder having a steel composition of SUS-304L or SUS-316L, 3D printing device using ceramic material. The method of claim 1,
The material stick compression rod moves finely along the length direction of an actuator so that a certain amount of material per unit area is discharged by finely adjusting the movement of the material stick compression rod. 3D printing apparatus using a ceramic material. The method of claim 2,
By finely adjusting the movement of the material stick compression rod, the speed of the melting nozzle moving along the outer circumferential surface of the three-dimensional object to be extruded and the amount of extrusion of the material stick are controlled so that a certain amount of material per unit area is discharged, and the curved section of the outer circumferential surface In the 3D printing apparatus using a ceramic material, the compression speed of the material stick is set to be slower than the compression speed of the material stick in a straight section of the outer peripheral surface. The method of claim 3,
The extrusion amount is calculated based on the following equation,
[Equation]

(Where d _e is the diameter of the material stick, l _e is the extrusion distance, d _s is the width of the extruded material, and l _s is the length of the extruded material)
3D printing device using ceramic material. The method of claim 1,
A melting unit disposed between the melting nozzle and the material barrel to melt one end of the material stick; And
3D printing apparatus using a ceramic material, further comprising a heat dissipation unit for preventing the heat generated from the molten unit from moving upward. The method of claim 1,
The material stick is manufactured by kneading at a temperature of 170° C. or higher, and the ceramic powder further comprises a polymeric binder including a binder, a plasticizer, and a lubricant. 3D printing apparatus using a ceramic material. According to 1,
One side of the material stick melted by the melting unit is in a semi-solid state and the other side is in a solid state, a three-dimensional printing apparatus using a ceramic material. The method of claim 1,
In the case of retraction of the material stick compression rod, the distance that the material stick compression rod moves upward as the pressure of the material stick compression rod is released and the pressure of the material stick compression rod is released is 3D printing apparatus using a ceramic material to adjust the position of the material stick compression rod to be longer than the distance moved upward in the material barrel.

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