KR20210037387A - Printing method of 3d printer - Google Patents

Abstract

The present invention relates to a 3D printer printing method, the 3D printer printing method comprising the following steps of: filling the 3D printer with ABS material; after setting the 3D printer to a predetermined working state, laminating the ABS material on a mold plate; and repeating the lamination step repeatedly for a predetermined number of layers, wherein the lamination step is performed in a longitudinal direction in-plane output method, in a width direction in-plane output method, in a longitudinal direction out-of-plane output method or in a width direction out-of-plane output method. The problem to be solved by the present invention is to improve the characteristics of a 3D printed material using the ABS material.

Description

3D printer printing method{PRINTING METHOD OF 3D PRINTER}

The present invention relates to a three-dimensional (3D) printing method, and more particularly, to a 3D printing method for improving the characteristics of a print using an ABS (acrylonitrile butadiene styrene) material.

3D printing refers to a technology that directly manufactures products based on 3D computer-aided design (CAD) information. Most 3D printing is a method of segmenting a 3D CAD model into a 2D layer and producing it using a lamination technique.

The advantage of 3D printing is that it is specialized in small-volume production, and it is possible to produce customized products and mold-free products. Types of 3D printing developed and used to date include fused deposition modeling (FDM), selective laser sintering (SLS), digital light processing (DLP), and stereolithography apparatus (SLA).

Among them, FDM, a representative 3D printing technology, melts the filament corresponding to the material in a heated nozzle and sprays it on a build platform to create a shape. FDM technology is mainly used for rapid prototyping of polymer parts, and the choice of material varies depending on the type or nature of the product.

Materials commonly used today include durable and environmentally friendly polylactic acid (PLA), nylon for soft products, high-density polyethylene (HDPE), and acrylonitrile butadiene styrene (ABS), a solution for parts with general strength.

Thanks to its various advantages, 3D printing is expanding its use field to a wide range of industrial fields such as bio and aerospace/space. However, it is known that it lacks mechanical properties compared to injection products as a disadvantage of 3D printing.

The problem to be solved by the present invention is to improve the characteristics of a 3D printed material using an ABS material.

A 3D printer printing method according to one aspect of the present invention for solving the above problem includes the steps of filling an ABS material in a 3D printer, setting the 3D printer to a predetermined working state, and then laminating the ABS material on a modeling plate, And repeating the stacking step repeatedly for a predetermined number of layers, wherein the stacking step includes a longitudinal in-plane output method, a width direction in-plane output method, a lengthwise out-of-plane output method, or a width direction out-of-plane output method.

The molding plate may be made of aluminum.

The 3D printer may have a nozzle diameter of 0.3 to 0.5 mm, and a nozzle temperature of 220 to 240°C.

The printing speed of the 3D printer may be 30 to 40 mm/s, and the working temperature of the printing operation may be 100° C.±2.5.

According to this feature, the tensile strength and bending strength of the printed material are improved.

1 is an example of a 3D printed material produced according to an embodiment of the present invention, and shows a printed material printed in a longitudinal direction in-plane output method (Lin) and a longitudinal direction out-of-plane output method (Lout).
2 is an example of a 3D printed material produced according to an embodiment of the present invention, and shows a printed material printed in a width direction in-plane output method (Win) and a width direction out-of-plane output method (Wout).
3 is a view showing a sample of a specimen for a tensile test on a printed product and dimensions of each part according to an embodiment of the present invention.
4 is a diagram showing a sample of a specimen for a bending test on a printed product and dimensions of each part according to an embodiment of the present invention.
5A is a graph showing the average tensile strength of a specimen printed by 3D printing according to an embodiment of the present invention.
5B is a graph showing a typical stress strain relationship for four specimens.
6A is a graph showing an average bending strength of a specimen printed by 3D printing according to an embodiment of the present invention.
Figure 6b shows the stress strain relationship in a typical three-point bending test.
7 is a graph showing tensile strength for specimens printed by 3D printing.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that adding a detailed description of a technology or configuration already known in the relevant field may make the subject matter of the present invention unclear, some of these will be omitted from the detailed description. In addition, terms used in the present specification are terms used to properly express embodiments of the present invention, which may vary according to related people or customs in the field. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

The terminology used herein is for reference only to specific embodiments and is not intended to limit the present invention. Singular forms as used herein also include plural forms unless the phrases clearly indicate the opposite. The meaning of'comprising' as used in the specification specifies a specific characteristic, region, integer, step, action, element and/or component, and other specific characteristic, region, integer, step, action, element, component and/or group It does not exclude the existence or addition of

Hereinafter, a 3D printing method using an ABS material according to an embodiment of the present invention will be described with reference to the accompanying drawings.

First, a 3D printed material using an ABS material according to the present embodiment will be described with reference to FIGS. 1 and 2.

1 and 2, the first and second printed matters 101 and 102 are positioned on the modeling plate 20, and are stacked in a thickness direction parallel to the modeling plate 50. ) Is the output format.

In addition, the second and fourth printed matters 103 and 104 are also positioned on the modeling plate 20 and are in an out-of-plane output format that is stacked in a state away from the modeling plate 20.

At this time, the first to fourth printed matters 101-104 may be made of ABS material, and the modeling plate 20 may be made of aluminum (Al).

Therefore, in order to print the first to fourth printed matter 101-104, first, the 3D printer is filled with an ABS material.

Then, after setting the 3D printer to a predetermined working state, the ABS material is laminated on a modeling plate, and this lamination operation is repeatedly performed repeatedly for a predetermined number of layers.

In the first to fourth printed matters 101-104, the height of each layer may be 0.1 to 0.3 m, and the working temperature (ie, bed temperature) may be 100° C.±2.5, and, in addition, a 3D printer The nozzle diameter of may be 0.3 to 0.5mm, the printing speed may be 30 to 40mm/s, and the nozzle temperature may be 220 to 240°C.

도로 가열된 알루미늄의 조형판(20)에 조건에 따른 패턴으로 적층을 수행하였다Therefore, the printed filament is 100

Lamination was performed in a pattern according to conditions on the molded plate 20 of aluminum heated on the road.

도로 가열된 알루미늄 조형판(20)에 조건에 따른 패턴으로 적층 동작을 수행한다.For printing of the first to fourth printed matters 101-104, the printed filament is 100

A lamination operation is performed on the aluminum molding plate 20 heated again in a pattern according to conditions.

In addition, the first and first outputs 101 and 102 manufactured with two types of in-plane outputs have the same stacking direction as the length direction of the printed material 101 (that is, a raster angle of 90 degrees). direction in plane: Lin)' and the stacking direction are divided into'width-direction in plane: Win', which is perpendicular to the length direction of the printed material 102.

Also, for the third and fourth outputs 103 and 104 manufactured with two types of out-of-plane outputs, the stacking direction is the same as the length direction of the output 103, and the stacking direction is the same as the'Longitudinal out-of-plane output (Lout)' and the stacking direction of the printed material 104 It is divided into'width direction out-of-plane output (Wout)' perpendicular to the length direction of ).

Accordingly, the printed matters 101-104 according to the present embodiment are made of an in-plane output method in the longitudinal direction, an in-plane output method in the width direction, an out-of-plane output method in the length direction, or an out-of-plane output method in the width direction.

The test results of tensile strength and bending strength for the printed product manufactured in this way are as follows.

3 and 4 are diagrams showing samples of a tensile specimen 301 for a tensile test and a bent specimen 401 for a bending test, and the dimensions of each part thereof.

Tensile specimen 301 was manufactured according to the tensile strength measurement method (ASTM 790-03) of the tensile strength measurement specimen standards, and the bending specimen 401 was manufactured by applying ASTM D 790-03.

Five specimens were tested for each given manufacturing condition (Win, Wout, Lin, Lout).

The measuring equipment used to measure the tensile strength of the manufactured tensile specimen is MTS's 858 Mini, and the main standard is 10kN/max. The applied load was measured through a load cell of 1kN capacity, and the lengthwise elongation length of the specimen was precisely measured using a contact extensometer manufactured by MTS. The strain rate during the tensile test was set to 1 mm/min.

The three-point bending test is a test method that allows more accurate mechanical properties to be grasped when the test object has brittle properties.

In order to measure the bending strength of the manufactured bent specimen, an experiment was performed according to ASTM D 790-03 standard.

The measurement equipment used at this time is Insight 1 of MTS, and the maximum load is 1kN/max as the main standard. The applied load was measured through a load cell of 250N capacity.

The bending test was performed using a three-point bending test jig of MTS (Max. length in transverse direction: 100mm). The strain rate during the bending test was set to 1 mm/min.

Five tensile specimens prepared for each condition were prepared and each flexural strength was measured. At this time, the maximum vertical stress by the bending test is as shown in [Equation 1].

Here, P is the load, L is the distance between the two hinges of the 3-section bending tester, b is the width of the specimen, and d is the thickness of the specimen. In addition, the maximum strain (ε _f ) at the center of the specimen is given by the following [Equation 2].

Where δ is the deflection at the center of the specimen.

5A shows the average tensile strength for specimens printed by 3D printing. Both Lin and Lout laminated in the longitudinal direction showed a value close to 40 MPa, and showed greater tensile strength than the Win and Wout cases laminated in the transverse direction.

It is believed that this is because the interfacial strength between the cross-sectional layers in the stacking direction, like the rigid mechanism of the fiber composite material, is smaller than the bonding force in the longitudinal stacking cross-sections connected in succession.

On the other hand, when comparing the case of in-plane manufacturing, which is a method of manufacturing by stacking horizontally on the modeling plate, and the case of out-of-plane manufacturing by stacking vertically on the modeling plate, the tensile strength of the out-of-plane lamination is greater than that of in-plane lamination due to slight differences.

For example, the tensile strength in the case of in-plane longitudinal lamination (Lin) was 36.1 MPa, while the tensile strength in the case of out-of-plane longitudinal lamination (Lout) was 39.5 MPa, which was excellent in out-of-plane lamination. In the case of out-of-plane lamination, it is estimated that the effect of removing defects that may exist in the lamination surface by the vertical load during lamination was to some extent.

In addition, in the case of Lin and Lout, it can be seen that the dispersion value of the tensile strength is relatively large.

Figure 5b shows the stress strain relationship for four representative specimens. In the case of transverse lamination (Win, Wout), the specimen shows brittle fracture behavior in which it fractures without deformation after the maximum stress, which is the cause of the large dispersion value of the tensile strength. On the other hand, fracture occurred while showing relatively very large elongation of Lout.

The following describes the bending test.

A three-point bending test was performed to study the effect of the stacking direction on the bending properties. The characteristics of the four specimens were similar to those of the tensile test, and the lowest bending stiffness was 32.5 MPa in the case of Win, and the largest bending stiffness was 69.1 MPa in the case of Lout.

In the case of the same lamination direction (eg, Win and Wout), the difference in tensile strength was not large, but as shown in FIG. 6A, in the case of the bending test, the difference in value occurred significantly. This was the same for Lin and Lout. In contrast to the tensile test, in the case of a bending test in which a load is applied from the side, it is judged that the stacking direction of the side also affects the bending stiffness.

Figure 6b shows the stress strain relationship in a typical three-point bending test. Similar to the tensile test, Win and Wout show brittle properties that break rapidly.

As confirmed through the above tensile and bending tests, the mechanical properties of the specimens manufactured by 3D printing are not isotropic but anisotropic.

In particular, since there is a vertical relationship between the stacking direction and the stacking surface, it can be explained by an orthotropic model.

The orthotropic model is defined by three mutually perpendicular planes of symmetry and consists of only nine independent constants (S _ijkl ) in the ductile matrix.

In the present invention, first, it is intended to establish an in-plane orthotropic model capable of describing the change in physical properties on the laminated surface. In the case of a relatively thin plate, an orthogonal anisotropy model defined by 9 independent constants can be simplified to an in-plane orthotropic model defined by 4 independent constants, and is shown in [Equation 3] below.

Here, e _i is the strain, g _ij is the shear strain, s _i is the normal stress, and t _ij is the shear stress. In order to determine the in-plane orthogonal anisotropy constant, an experiment consisting of 45 degrees of lamination was required, and an additional tensile test was performed for this (FIG. 5). Ex and Ey can be obtained through a tensile test, and Gxy can be obtained from the relational expression shown in [Equation 4] below.

Therefore, the coefficient of orthotropy stiff matrix of ABS is calculated from the given experimental values and summarized in [Table 1].

Isotropy In-plane orthotropy E 2.27 GPa E x 2.33GPa E y 2.22GPa G xy 1.11GPa

As such, the conclusion of the experiment on the anisotropic property of the printout when manufacturing FDM 3D printing using ABS material can be as follows.

First, the tensile strength according to the lamination showed the best out-of-plane output (Lout) in the longitudinal direction and the lowest in-plane output (Win) in the width direction. In particular, the outputs in the width direction show brittle fracture characteristics and are considered to be the cause of a large dispersion value of the tensile strength.

Second, the bending stiffness characteristics showed similarity to that of the tensile test, and as a result, the lowest bending stiffness was the case of in-plane output (Win) in the width direction. For the same stacking direction (e.g. Win and Wout), there is a significant difference in bending stiffness. In contrast to the tensile test, in the case of a bending test in which a load is applied from the side, it is judged that the stacking direction of the side also affects the bending stiffness.

Third, the in-plane orthogonal anisotropy constant of ABS was determined, and it is judged that this will be useful information for the analysis of the object to be designed by 3D printing.

In the above, the embodiments of the present invention have been described. The present invention is not limited to the above-described embodiments and the accompanying drawings, and various modifications and variations are possible from the viewpoint of those of ordinary skill in the field to which the present invention pertains. Therefore, the scope of the present invention should be defined by the claims of the present specification as well as those equivalents to the claims.

Claims (4)

Filling the 3D printer with ABS material,
After setting the 3D printer to a predetermined working state, laminating the ABS material on a modeling plate, and
Repeating the stacking step repeatedly for a predetermined number of layers
Including,
The loading step consists of a longitudinal direction in-plane output method, a width direction in-plane output method, a longitudinal direction out-of-plane output method, or a width direction out-of-plane output method.
3D printer printing method. In claim 1,
The molding plate is a 3D printer printing method made of aluminum. In claim 1,
The nozzle diameter of the 3D printer is 0.3 to 0.5mm, the nozzle temperature is 220 to 240 ℃ 3D printer printing method. In paragraph 3,
The printing speed of the 3D printer is 30 to 40mm/s, and the working temperature of the printing operation is 100°C±2.5.

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