KR102120719B1 - 3D printer and 3D model printing method based on material extrusion type - Google Patents

Abstract

The material extrusion type 3D printer according to the present invention includes: filament materials prepared by adjusting the compounding ratio of metal nanoparticles stepwise; A material spool for receiving the filament materials; An output plate supporting a 3D model in which one or more of the filament materials are selectively melted and ejected; Nozzles that receive each of the filament materials accommodated in the material spool and selectively drive one or more to melt and discharge the filament material supplied to them; Extruders for supplying each of the filament materials accommodated in the material spool to each of the furnaces; And an XYZ axis driving unit for changing the position of the nozzle, wherein the nozzles and the extruders selectively drive only one or more nozzles and extruders selected to form the 3D model.

Description

3D printer and 3D model printing method based on material extrusion type}

The present invention relates to a 3D printing technology, and more particularly, to a 3D printer and a 3D model printing method of a material extrusion method that performs 3D printing with a filament material produced by mixing metal nanoparticles to have a difference in radiation attenuation rate. It is about.

3D printing technology is currently being widely used in the medical field for the production of a human body model for simulation of surgery, model production for education of medical staff or medical practitioners, the production of surgical guides and surgical tools to assist with surgery, and the production of direct treatments.

In particular, 3D printing technology is widely used in the production of human body models for the purpose of planning and practicing difficult surgery in advance, and real cases that are not simple standard models, reflecting medically meaningful cases, and making models for education or practice. Trend.

1 illustrates a model of a human body device manufactured by 3D printing, and is excellent as a means for simulating the external shape of a human body modeling or visualizing it by reflecting colors, and can accurately visualize individual disease cases. However, in radiographic or MRI imaging, there is little difficulty in using it as a simulation or practice model because there is little change in contrast between tissues due to uniform material characteristics.

As such, current 3D printing materials and equipment technologies simulate the external shape of each human tissue or part, or produce color-coded tissues to improve visibility, or physical properties (softness, hardness) for each tissue. It could be expressed differently.

However, since there is no significant difference in the average atomic weight or density of materials that can be used in one 3D printer, there is little difference in the attenuation rate characteristics per unit volume for radiation such as X-rays. There was a limitation that the contrast effect was not effective due to the difference in attenuation rate characteristics by tissue. As a result, it was difficult to be used as a simulation or practice model in the medical imaging field that required to reflect even the attenuation rate characteristics of each human tissue.

In addition, it was difficult to utilize MRI medical imaging as a magnetic resonance method as an educational or simulation model.

2 and 3 illustrate a conventional human body model. 2 is an example of a standard human body model, and is produced only in a standardized uniform model form, not reflecting a case of a specific patient or a special condition, and is manufactured in a traditional manner such as injection or molding. 3 illustrates an image of a medical image of a standard human body model, and it is difficult to make a detailed classification of tissues because the contrast of each tissue is not clear.

Accordingly, in the prior art, the development of a 3D printing technology capable of simulating the difference in the radiation attenuation rate of each human tissue is urgently desired.

Republic of Korea Patent Publication No. 1020170047550 Republic of Korea Patent Publication No. 1020170118387 Republic of Korea Patent Publication No. 1020180032155 Republic of Korea Patent Publication No. 1020170074059

The present invention performs 3D printing using filament materials mixed with metal nanoparticles so as to have a difference in radiation attenuation rate. 3D printer and 3D model of a material extrusion method capable of simulating the difference in radiation attenuation rate for each human tissue. It is an object to provide a printing method.

3D printer of the material extrusion method according to the present invention for achieving the above object, filament material prepared by adjusting the compounding ratio of the metal nanoparticles step by step; A material spool for receiving the filament materials; An output plate for supporting a 3D human body model in which one or more of the filament materials are selectively formed by discharging molten melt; Nozzles that receive each of the filament materials accommodated in the material spool and selectively drive one or more to melt and discharge the filament material supplied to them; Extruders for supplying each of the filament materials accommodated in the material spool to each of the nozzles; And an XYZ axis driving unit for varying the position of the nozzle, wherein the nozzles and the extruders selectively drive only one or more nozzles and extruders selected to form the 3D human body model.

The present invention described above causes an effect to simulate the difference in radiation attenuation rate for each tissue of the human body by performing 3D printing using filament materials mixed with metal nanoparticles to have a difference in radiation attenuation rate.

The present invention simulates the difference in the radiation attenuation rate for each tissue of the human body and causes an effect of enabling detailed separation of tissues by clearly revealing the contrast of each tissue when photographing a medical image of the human body model.

1 is a diagram illustrating a human body model produced by 3D printing.
Figure 2 is a diagram illustrating a conventional human body model.
Figure 3 is a diagram illustrating a medical imaging image of a conventional standard human body model.
4 is a diagram illustrating a process of manufacturing a filament material for a 3D printer according to a preferred embodiment of the present invention.
5 is a diagram illustrating a filament material for a 3D printer according to a preferred embodiment of the present invention.
6 is a view showing the structure of a filament material for a 3D printer according to a preferred embodiment of the present invention.
7 is a diagram illustrating an X-ray attenuation or transmission process of a filament material for a 3D printer according to the present invention.
8 and 9 are diagrams illustrating an X-ray attenuation amount of a filament material for a 3D printer according to the present invention.
10 is a configuration diagram of a material extrusion method 3D printer according to a preferred embodiment of the present invention.
11 is a diagram illustrating a process of manufacturing a human body model with a material extrusion method 3D printer according to a preferred embodiment of the present invention.
12 is a diagram illustrating an expected view of an X-ray image of a human body model manufactured according to a preferred embodiment of the present invention.
13 is a diagram illustrating the characteristics of a guide for adjusting the dose produced by a 3D printer of a material extrusion method according to a preferred embodiment of the present invention.

The present invention makes it possible to simulate the difference in the radiation attenuation rate for each tissue of the human body by manufacturing a filament in which metal nanoparticles are mixed to have a difference in the radiation attenuation rate and performing 3D printing using the filament.

The present invention simulates the difference in the radiation attenuation rate for each tissue of the human body, thereby enabling detailed separation of tissues by clearly revealing the contrast for each tissue when photographing a medical image of the human body model.

Table 1 shows the characteristics of the human body's mass density, absorption coefficient A, and X-ray energy absorption (attenuation).

division Mass Density
(kg/m3) Absorption coefficient A Permeability (P) Absorbency converted based on air (X) muscle 1090 1.36 0.000235 1302 Fat 911 1.36 0.000282 1088 lungs 1050 1.367 0.000243 1263 Expanded lungs 394 1.367 0.000647 474 air 1.2 One 0.306566 One bone 1908 1.568 0.000109 2806 Iron oxide nano powder
(Fe ₃ O ₄₎ 5170 2.29 1.96E-05 15651

Since the actual material has a different mass density depending on its composition, it is necessary to calculate the actual absorbance in consideration of the intrinsic mass density without considering the intrinsic absorption coefficient according to the material. Thus, the mass density is divided by the obtained value to estimate the permeability per unit area after the final attenuation. For example, P=I/Density, I=I _{0 ·} exp(-A·T), where I: refers to the amount of transmitted energy, and I ₀ : refers to the amount of incident energy.

Therefore, after calculating the total amount of energy transmitted per major material, the energy X-ray energy absorption is defined as energy absorption X as a relative value based on air.

Referring to Table 1, in the case of human tissue, in addition to the difference in the average atomic weight according to the molecular combination for each tissue, the mass density per unit volume of tissue is different for each tissue, and the X-ray absorbance is also different for each tissue. In addition, the degree of energy absorption may be different depending on the detailed structure of the soft tissue. This is because if there are pores inside the tissue, there is also a part filled with blood or body fluid, so even if the average atomic number is similar, the difference in absorbance of the actual X-rays may be large.

For example, in X-ray absorptivity, muscle 1302, fat 1088, lung 1263, and bone 2806, bones have the highest X-ray absorption rate among human tissues, and muscles, lungs, and fats have tissue-specific differences. . In addition, the X-ray absorbance is referred to as HU Value (Hound Field Unit Value) in medical images such as CT and has been quantified and utilized.

On the other hand, the material used in the general material extrusion method 3D printer has almost no variation due to the material density because the density is always uniform, except in the case of printing in a lattice structure. In the case of the human body model produced by 3D printing, There is no large deviation in the X-ray energy absorption rate (attenuation rate) for each tissue.

Accordingly, the present invention includes metal nanoparticles in a filament material used in a material extrusion (ME) 3D printer, so that 3D printing with a difference in radiation attenuation rate can be performed. The present invention simulates the difference in the radiation attenuation rate for each tissue of the human body, thereby enabling detailed separation of tissues by clearly revealing the contrast for each tissue when photographing a medical image of the human body model.

<Filament material manufacturing process>

4 illustrates a process for manufacturing a filament material for a 3D printer according to a preferred embodiment of the present invention, and the process for manufacturing the filament material will be described with reference to FIG. 4.

First, filament raw materials such as ABS, PLA, TPU, nylon, PET, and silicon are melted. Thereafter, metal nanoparticles are mixed in the molten filament raw material in a constant ratio, and the metal nanoparticles are uniformly distributed in the filament raw material in a uniform concentration. For example, the metal nanoparticles are preferably iron oxide nanoparticles, and the higher the mixing ratio of the metal nanoparticles, the higher the attenuation rate of X-rays is, so the attenuation rate of X-rays can be controlled by adjusting the mixing ratio of the metal nanoparticles.

In more detail, the method of calculating the mass absorption coefficient of a material containing two or more elements is the same as in Equation 1, and according to Equation 1, the metal nano has a much higher atomic mass than 3D printing raw materials such as plastic and acrylic. When mixing particles, the absorption coefficient (attenuation rate) of X-rays can be changed according to the mixing ratio.

Referring to Equation 1 below, the absorption coefficient (μ/ρ) of a mixed material containing two or more elements is equal to the sum of the product of the absorption coefficient of each mixture and the mass divided by the total mass.

Therefore, since the mass density differs depending on the composition of the actual substance, it is necessary to obtain the energy absorption degree of the mixture by reflecting this, and when calculating the final energy absorption degree of the actual object multiplied by the mass density, it can be calculated as follows.

A = (A1 x w1 + A2 * w2) / (w1 + w2)

(A1, A2 is the energy absorption rate of each material, w1, w2 is the mass of each material)

As shown in Table 1, since the average energy absorption of soft tissue (skin/muscle, etc.) is 1302, the energy absorption of bone is 2806, and the energy absorption of fat is 1088, etc., for example, Fe ₃ O ₄ as metal nanoparticles If (iron oxide) is applied, the energy absorption value of the nanoparticles is estimated to be 15651. This can be found through example data of the mass absorption coefficients for each major substance on the NIST site, and can be found via the following link (https://physics.nist.gov/PhysRefData/XrayMassCoef/tab3.html, https:// physics.nist.gov/PhysRefData/XrayMassCoef/tab4.html)

First, first, filament raw materials such as ABS, PLA, TPU, nylon, PET, and silicon are melted. Thereafter, iron oxide metal nanoparticles are mixed in the molten filament raw material in a constant ratio, and the metal nanoparticles are uniformly distributed in the filament raw material in a uniform concentration. For example, as the mixing ratio of the iron oxide nanoparticles increases, it can be seen that the X-ray absorption increases, and the mixing ratio of the iron oxide nanoparticles can be adjusted to control the X-ray absorption. That is, assuming the case of using a filament material having an energy absorption of 450, for example, when mixing iron oxide nanoparticles having an energy absorption of 15651, energy absorption can be obtained as shown in Table 2 according to the relative ratio.

Filament composition ratio (%) 100 0 99.85 95.8 84.5 Iron oxide nanoparticles
Composition ratio (%) 0 100 0.15 4.2 15.5 Absorbency (X) 450 15651 472.8 1088 2806

In Table 2, for example, it can be seen that the energy absorption values of fat 1088 and bone 2806, respectively, are approximated, and in the case of expanded lung 474, the composition ratio of iron oxide nanoparticles is within 0.15% by weight. Mixing in the range, and in the case of the contracted lung 1263 and muscle 1303, it can be obtained by mixing in a range of 4.2% by weight or more and 15.5% by weight or more to obtain an approximate value for energy absorption.

Accordingly, considering the X-ray absorption rate for each tissue (part) of the 3D human body model to be manufactured, 3D printing may be performed by applying a different filament material to be used according to each part or tissue model. Therefore, basically, the mixing ratio of the metal nanoparticle mixed polymer allows the energy absorption to have a level similar to bone (2806) among the tissues of the human body, so that the tissues of the human body having lower energy absorption than bones can be combined at desired stages. Can be. In addition, although an example of using iron oxide nanoparticles (molecular weight 33.08) is given, in practice, metal nanoparticles having a higher average atomic weight, such as iodine (molecular weight 53), barium (molecular weight 56), etc. may be used. However, iron oxide nanoparticles are already used in various ways as harmless substances, and the price is relatively low, so iron oxide is used as an example. If the substance is harmless to humans, other nanoparticles can be used, and the X-ray energy of the substance Depending on the absorption rate, the composition ratio can be recombined.

In addition, the case of using the mixture ratio in the range for simulating human tissue is exemplified in the present invention, and when the desired absorption rate is higher, the composition ratio of the metal nanoparticles may be higher.

The present invention, as described above, by extruding and drawing the mixture of the metal nanoparticles evenly distributed in the raw material in the form of a wire to produce a filamentary material similar to a fishing line. 5 illustrates a wire-like filament material similar to a fishing line. And it is Figure 6 shows the structure of the filament material including the metal nanoparticles. The above-mentioned metal nanoparticles are particles having a very fine size of several nanometers to hundreds of nanometers, and in fact, ultrafine metal particles of a level that cannot distinguish the size of the grains with the naked eye are distributed in the filament material.

7 illustrates an X-ray attenuation or transmission process of a filament material for a 3D printer according to the present invention, and when irradiating X-rays due to metal nanoparticles present inside the filament material, it is higher than that of a general filament material. It has an X-ray attenuation rate.

Figure 8 illustrates the difference in the amount of X-ray attenuation according to the mixing ratio of the metal nanoparticles, to prepare a filament material having a higher or lower attenuation rate of X-rays according to the mixing ratio and relative concentration of the metal nanoparticles mixed in the filament raw material It can be made and it is apparent to those skilled in the art by the present invention.

FIG. 9 illustrates the difference in X-ray attenuation according to the mixing ratio and thickness of metal nanoparticles. Even if a shape is output with a filament material containing the same concentration of metal nanoparticles, the X-ray attenuation rate becomes higher as the thickness increases. , Even if the shape has the same thickness, the higher the mixing ratio of the metal nanoparticles, the higher the attenuation rate of X-rays.

By using the filament materials in which the compounding ratio of the metal nanoparticles is adjusted stepwise according to the above-described method, the present invention enables to simulate the energy absorption or attenuation rate of different X-rays for each human tissue.

Utilizing such filaments, 3D printing production with filament materials having different metal nanoparticle concentrations or blending ratios for different human tissues is not only a simulation of the external shape of human tissues, but also a more human and human body even when photographed in medical imaging equipment. A human body model having a contrast ratio of similar images can be produced.

<3D printer with material extrusion method>

The configuration of a 3D printer that performs 3D printing with a filament according to a preferred embodiment of the present invention will be described with reference to FIG. 10.

The material extrusion type 3D printer includes a material spool 100, extruders 102, XYZ axis driving unit 104, nozzles 106, output plate 108, motor and driving unit 110, and a molding plate heater ( 112) and a shape control bed 114.

The filament materials are prepared by adjusting the compounding ratio of the metal nanoparticles step by step, and the filament materials include a predetermined ratio of the filament raw material and the metal nanoparticles including at least one of ABS, PLA, TPU, nylon, PET, and silicon. It is prepared by mixing, the diameter of the metal nanoparticles is from several nm to several hundred nm. Here, iron oxide nanoparticles are employed as the metal nanoparticles. In addition, as the mixing ratio of the metal nanoparticles increases, the attenuation rate of X-rays also increases, so the mixing ratio of the metal nanoparticles of the filament materials is adjusted to control the attenuation rate of X-rays.

The material spool 100 accommodates the filament materials.

The output plate 108 supports a molding formed by aggregating one or more of the filament materials selectively melted, and the output plate is located on the upper surface of the shape control bed 114.

The nozzles 106 are supplied with each of the filament materials accommodated in the material spool 100, and one or more nozzles are selectively driven by a control device not shown to melt the filament material to output the plate 108 Discharge.

The extruders 102 respectively supply the filament materials accommodated in the material spool 100 to the nozzles 106, and the supply amount is controlled by the control unit not shown.

The XYZ-axis driving unit 104 changes the position of the nozzles 106 according to the 3D model, so that the nozzles 106 discharge the melt melted by the filament material according to the 3D model.

The shape control bed 114 mounts the output plate 108.

The motor and driving unit 110 drives the shape control bed 114 to position the output plate 108 at a position for forming a 3D modeled sculpture.

A molding plate heater 112 is positioned below the shape control bed 114 to heat the filament melt for the shape of the fixture.

3D printer of the material extrusion method according to the present invention configured as described above, one or more extruders selected for forming a 3D model of the extruders 102 are filament materials prepared by adjusting the compounding ratio of the metal nanoparticles step by step One or more filament materials are supplied to one or more nozzles, and the XYZ axis drive unit 104 changes the XYZ position of the nozzles 106 to a position for forming a 3D model, and the 3D model of the nozzles 106 One or more nozzles selected for formation are supplied with the one or more filament materials, melted, and discharged to the output plate 108 to print a 3D model.

When the filament material having the compounding ratio of the metal nanoparticles according to the present invention prepared and used step by step is used, it is possible to simulate energy absorption and attenuation rates of different X-rays for different human tissues as necessary, and through this, each human tissue is used for each other. If 3D printing production is performed with a filament material having a different metal nanoparticle concentration, that is, a blending ratio, it is only a simulation of the external shape of human tissue and can have a contrast ratio similar to that of a human body even when photographed in medical imaging equipment. A human body model can be produced, which is as illustrated in FIG. 11, and the predicted view of the X-ray image of the human body model is as illustrated in FIG. 12.

In addition, using the material and 3D printing technology according to the present invention, in addition to manufacturing a human model for surgery planning and simulation, a surgical training model, and a model for practicing medical images, the advantage of freely producing a desired 3D shape and the attenuation rate of radiation And by using the advantage of controlling the transmittance, radiation or proton radiation is intensively irradiated only to the targeted area during radiation therapy, and can be used to manufacture a guide for dose adjustment to minimize radiation dose to normal human tissue. 13 shows an example of manufacturing a guide for dose adjustment.

Thus, the guide for adjusting the dose of FIG. 13 can be used as an energy absorber for radiation treatment, and thus can be used by setting the absorbance of bone 2806 of Table 1 higher than that.

In addition, when used as iron oxide nanoparticles, which are also used as an enhancement agent for improving the image quality of a magnetic resonance imaging device (MRI) as a metal nanoparticle, in addition to radiography (X-ray, CT), tissues are also used in MRI images. It is possible to produce a 3D human body model to have a difference in image characteristics for each part.

In addition, the material extrusion method 3D printer filament material proposed in the present invention, in addition to the expression of various physical properties having a difference in ductility, hardness, and color of the raw material, makes it possible to produce metal nanoparticles in various proportions to make it medical It is also possible to have a contrast characteristic, which is an image characteristic similar to the tissue of the human body, when taking an image.

100: material spool
102: extruder
104: XYZ axis driving unit
106: nozzle
108: output plate
110: motor and drive unit
112: molding plate heater
114: shape control bed

Claims (10)

In the material extrusion method 3D printer,
Filament materials prepared by adjusting the compounding ratio of the metal nanoparticles stepwise;
A material spool for receiving the filament materials; An output plate for supporting a 3D human body model in which one or more of the filament materials are selectively formed by discharging molten melt; Nozzles that receive each of the filament materials accommodated in the material spool and selectively drive one or more to melt and discharge the filament material supplied to them; Extruders for supplying each of the filament materials accommodated in the material spool to each of the nozzles; And an XYZ axis driving unit for changing the position of the nozzle.
The nozzles and the extruders selectively drive only one or more nozzles and extruders selected to form the 3D human body model,
The filament materials, ABS, PLA, TPU, nylon, PET, a filament raw material comprising one or more of silicon and metal nanoparticles are mixed in a predetermined ratio,
Since the absorption rate of X-rays increases as the mixing ratio of the metal nanoparticles increases, the absorption rate of X-rays is controlled by adjusting the mixing ratio of the metal nanoparticles,
3D printer of the material extrusion method, characterized in that the adjusted absorbance of the X-rays is set according to the absorbance of each part of the 3D human body model. According to claim 1,
The metal nanoparticle is a material extrusion method 3D printer, characterized in that the iron oxide nanoparticles. According to claim 1,
The 3D human body model is a material extrusion method 3D printer, characterized in that any one of a human body model for surgical planning and simulation, a surgical training model, and a medical image practice model.
According to claim 1,
The 3D human body model is a material extrusion method 3D printer, characterized in that the guide for dose adjustment.
In the 3D model printing method of material extrusion method,
One or more extruders selected for forming a 3D human body model among the extruders, supplying at least one filament material of at least one of the filament materials produced by adjusting the compounding ratio of the metal nanoparticles stepwise;
The XYZ axis driving unit varies the XYZ position of the nozzles to a position for forming the 3D human body model;
Including one or more nozzles selected to form the 3D human body model among the nozzles are supplied with the one or more filament materials, melted, and discharged to an output plate to print the 3D human body model.
The filament materials,
Filament raw materials and metal nanoparticles including one or more of ABS, PLA, TPU, nylon, PET, and silicon are mixed and prepared in a predetermined ratio,
As the mixing ratio of the metal nanoparticles increases, the absorbance of X-rays also increases, so the absorption ratio of the X-rays is controlled by adjusting the mixing ratio of the metal nanoparticles,
The 3D model printing method of the material extrusion method, characterized in that the adjusted absorbance of the X-rays is set according to the absorbance of each part of the 3D human body model. The method of claim 5,
The metal nanoparticles are 3D model printing method of the material extrusion method, characterized in that the iron oxide nanoparticles. The method of claim 5,
The 3D human body model is a 3D model printing method of a material extrusion method, characterized in that it is one of a human body model for surgical planning and simulation, a surgical training model, and a medical image practice model. The method of claim 5,
The 3D human body model is a material extrusion method 3D model printing method, characterized in that the guide for dose adjustment. delete delete

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