KR102308544B1 - 3D Printer - Google Patents

Abstract

The 3D printer includes a data receiving unit that receives 3D molding information of a 3D molding, a molding plate on which a molding formed by curing and laminating a molding plane having a plurality of objects is supported, and an exposure image including each object among 3D molding information as a molding plane Stores the width information about the width of the exposure unit and object for photocuring molding by exposing to, and determining whether each object included in the exposure image among the 3D molding information has a width less than a preset width, and the determined object and a control unit for controlling the exposure unit so that the width light amount information according to the width of the object is exposed to the object.

Description

3D Printer {3D Printer}

The present invention relates to a 3D printer, and more particularly, to a 3D printer capable of uniformly exposing curing during a molding process of a molded article formed by lamination by exposure curing.

A DLP (Digital Light Processing) 3D printer is cured by exposing ultraviolet rays to a molding plane of an exposed image having a plurality of objects, and repeatedly laminating them to mold a molding. A plurality of objects exist in the exposure image, and the objects have various sizes and shapes.

Referring to FIG. 1 , square objects a to e of different sizes (0.3 to 5 mm) are shown in the forming plane of FIG. 1 (a). Figure 1 (b) shows the degree of curing of each object after exposing the same amount of UV light to the entire molding plane. Due to the characteristics of DLP 3D printing, it can be seen that over-curing occurs when an object becomes large based on a specific size, and non-curing occurs when an object is small. It can be seen that a difference in curing accuracy by the same exposure occurs according to a difference in object size. In particular, when a small object and a large object are complex among exposure images including jewelry, there is a problem in that the problem increases.

Accordingly, it is an object of the present invention to provide a 3D printer capable of exposing an exposure image having objects of various sizes so that uniform curing can be achieved.

3D printer according to the present invention for achieving the above object, a data receiving unit for receiving 3D molding information of a 3D molding; a molding plate on which a molding formed by curing and laminating a molding plane having a plurality of objects is supported; an exposure unit for photocuring molding by exposing an exposure image including each object among the 3D molding information to the molding plane; and storing width light amount information for the width of the object, determining whether each object included in the exposure image among the 3D molding information has a width less than a preset width, and determining whether each object has a width less than a preset width and a control unit controlling the exposure unit to be exposed to the object by applying the width light amount information. By applying the width light amount information corresponding to the object width less than the preset width to expose each object, uniform curing is achieved throughout the exposure image, thereby improving the molding quality of the molded product.

Here, the control unit stores the area light amount information for the area of the object, and applies the area light amount information according to the area of each object included in the exposure image among the 3D molding information to expose the object. Since the exposure can be performed by adjusting the amount of light according to the area of each object, more uniform curing of the entire exposed image can be achieved.

Here, the control unit extracts a detailed object region from the object based on a reference line in which a plurality of unit region cells are arranged in a grid structure, and applies the area light amount information according to the area of the extracted detailed object region to obtain the detailed information. The exposure unit may be controlled to expose the object area.

According to the present invention, by applying the width light amount information corresponding to the width of the object less than the preset width to expose each object, uniform curing is achieved over the entire exposure image, so that the molding quality of the molding can be improved.

1 is an explanatory view of an exposure image and curing degree in a conventional 3D printer.
2 is a simplified diagram of a 3D printer according to the present invention.
Fig. 3 is an explanatory view of conventional exposure and exposure according to the present invention;
4 is an explanatory view of the degree of curing according to an embodiment of the present invention.
5 is a control block diagram.
6 is an explanatory diagram illustrating a cross-section of an object A to which different exposure conditions are to be applied for each area;
7A and 7B are conceptual views illustrating a method of extracting a detailed object area from a cross section of an object A;
8 is a conceptual diagram of extracting one detailed object area from one cross section of object B;

Hereinafter, the 3D printer 1 according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a simplified diagram of the 3D printer 1 according to the present invention, FIG. 3 is an explanatory diagram of conventional exposure and exposure according to the present invention, and FIG. 4 is an explanatory diagram of the degree of curing according to an embodiment of the present invention. , FIG. 5 is a control block diagram, FIG. 6 is an explanatory diagram illustrating a cross-section of object A to which different exposure conditions must be applied for each area, and FIGS. 7A and 7B are detailed object regions in one cross-section of object A It is a conceptual diagram illustrating a method of extracting, and FIG. 8 is a conceptual diagram of extracting one detailed object area from one cross section of object B. As shown in FIG.

The 3D printer 1 includes a data receiving unit 10 , a bed 20 , a molding plate unit 30 , an exposure unit 40 , a molding driving unit 31 , a resin tank 60 and a control unit 70 .

The data receiving unit 10 is provided as a communication unit to receive 3D molding information of a 3D molding from the outside. The data receiving unit 10 transmits the received 3D molding information to the control unit 70 to be described later.

The bed 20 is spaced apart from the bottom surface by the support pillars supporting the bottom surface. The bed 20 provides an upper surface of the base on which the molding is made. The bed 20 may support a molding plate unit 30 , an exposure unit 40 , a molding driving unit 31 , and a control unit 70 to be described later.

The molding plate unit 30 is composed of a molding plate connection part 50 and a molding plate 32, and supports a molding formed by laminating a molding plane having a plurality of objects by curing.

The molding plate 32 is a simple plate-shaped body that can be detached from the molding plate connection part 50, and the molding plane hardened in the molding process can be fixed to the lower surface of the molding plate.

The resin tank 60 is generally made of a transparent material for the bottom plate, and has a resin receiving portion in the shape of a container or storage tank capable of storing the photocurable resin. A molding plate 32 supporting the molding may be disposed in the resin tank 60 , and the upper portion of the resin receiving portion is formed in an open shape so that the molding plate 32 is immersed and then movable upward.

The resin tank 60 is supported by the bed 20 , and the elastic bottom plate 150 formed in the form of a thin sheet or film is interposed at the bottom of the resin tank 60 .

The photocurable resin is cured on one surface of the elastic bottom plate 150 and laminated on the molding plate 32, and the molding plate 32 rises by the thickness of the molding plane to be cured next by the molding driving unit 31 to cure the resin. and the lamination process is repeated. Therefore, the elastic sole plate 150 needs to be separated for each molding layer, and it is preferable to coat the surface of the elastic sole plate 150 in order to facilitate separation from the molding layer.

Materials for coating the elastic bottom plate 150 include Teflon, polyester (PE), ethylene tetrafluoride (TFE), ethylene hexafluoropropylene tetrafluoride (FEP), ethylene tetrafluoride perfluoroalkoxyethylene (PFA), and ethylene. Fluorine material coating agents such as tetrafluoroethylene (ETFE), vinylidene prolide (PVDF), vinyl prolide (PVF), chlorotrifluoroethylene (DTFE), and ethylene chlorotrifluoroethylene (ECTFE) are possible. In addition, it may be coated using an anti-fingerprint coating agent for water repellency, an anti-fingerprint coating agent for oil repellency, a low reflection coating agent, and a release coating agent. Here, the low-reflection coating agent is preferably made of silicon dioxide (SiO2), zirconia (ZrO2), indium tin oxide, titanium dioxide (TiO2), or aluminum oxide (Al2O3).

In some cases, a film layer (not shown) coated on the elastic bottom plate 150 may be laminated on the outer surface and used. Here, the upper surface of the film layer (not shown) is coated with at least one material of the above-described coating agents, and an adhesive is applied to the rear surface of the film layer (not shown) to adhere to the elastic bottom plate 150 . The film layer (not shown) may be laminated in the form of a wide plate or by connecting a plurality of tapes.

The shaping driving unit 31 has a shaping lifting rail (not shown) and a shaping support column (not shown) that are supported by the bed 20 and stand upward. The modeling lifting rail (not shown) is provided as a rail or a double tube that is fixedly coupled to a modeling support column (not shown) to move the molding plate 32 up and down.

The control unit 70 transmits a control signal to the driving motor (not shown) and the molding driving unit 31 through the molding plate driving unit control signal line, and gradually moving the molding plate unit 30 at intervals of the unit molding layer to mold the molding. can be raised or lowered.

The user input unit 72 includes various types of input interface related circuits provided to input a user's command. For example, it may be implemented as a mechanical or electronic button, a remote controller separated from the 3D printer 1, a touchpad, and the like. A user or operator sets the 3D printer 1 in various modes through manipulation of the user input unit 72 . For example, an object to be molded may require a faster manufacturing time rather than precise molding depending on the intended use. In particular, this is the case for the molding section in the shape portion that is not assembled or combined with other counterparts. In the molding section that requires a faster manufacturing time than precision, even if it is partially affected by over-curing or non-curing, the user input unit 72 is used to adjust the photo-curing exposure energy or omit other processes to complete the production of the molded product within a short time. You can set the operation mode through

The exposure unit 40 performs photocuring molding by exposing an exposure image including each object in the 3D molding information on a molding plane toward the molding plate 32 . The exposure unit 40 has an exposure lamp 41 and an output filter 42 .

The exposure lamp 41 outputs ultraviolet rays toward the exposure image to cure the photocurable resin on the molding plane.

The output filter 42 outputs the curing wavelength only to the exposure molding area of the 3D molding information.

Here, the exposure lamp 41 may output the light of the curing wavelength of the exposure image to the molding plane by adjusting the pixels by itself, and the output filter 42 may be adjusted to correspond to the exposure image by the control unit 70 to It is also possible to perform an exposure operation of a scale.

Meanwhile, the exposure unit 40 of the present invention may use various optical devices such as a project method and an LCD method.

In particular, the exposure part of the LCD type has a relatively short focal length compared to other light sources, so that it can be installed in close contact with or close to the molding surface. At this time, the LCD light source may be integrated with the resin tank and may rise or fall non-flatly.

In some cases, the molding driving unit 31 includes an exposure unit moving driving unit capable of moving the exposure lamp 41 up, down, left and right, or a molding plate lifting and lowering driving unit 52 capable of horizontally moving the molding plate unit 30. can be provided. When a discharging unit for discharging the photocurable resin is provided and when a blade for applying the photocurable resin to the molding plane is provided, the molding driving unit 31 may include a discharging unit driving unit and a blade driving unit.

The control unit 70 stores width light amount information for the width of the object, determines whether each object included in the exposure image among the 3D molding information has a width less than a preset width, and determines the width according to the width of the object The exposure unit 40 is controlled so that the light amount information is exposed to the object.

The control unit 70 stores the area light amount information for the area of the object, and allows the area light amount information according to the area of each object included in the exposure image among the 3D molding information to be exposed to the object.

It is explanatory drawing of the conventional exposure and exposure by this invention.

3 (a) Conventionally, even if the sizes of the objects f, g, and h are different, they are cured by exposure to the same amount of light 255. In particular, the object boundary area is not reliably cured, so precise molding was not performed. .

3 (b) Exposure by setting different amounts of light (for example, F=187, G=170, H=255) according to the size, shape area, etc. of the objects (F, G, H) on the exposure image according to the present invention Since this is done, hardening of the object, that is, hardening of the boundary area, can be precisely performed. Accordingly, the molding quality can be remarkably improved because the molding can be manufactured precisely.

As described above, an algorithm for uniformly adjusting the brightness of each object in the exposure image in which the image brightness, that is, the amount of light is set to 255, was produced. That is, it can be said that an object with a large mass is expressed as dark, and an object with a small mass is expressed as bright. At this time, not only the area but also various information such as shape were used to index.

4 is an explanatory view of the degree of curing according to an embodiment of the present invention.

As a result of exposing objects a to e in FIG. 1 by adjusting the amount of light differently for each object according to the present invention, the degree of curing is improved. In particular, it can be seen that the degree of hardening is remarkably improved in the object size c, which is 1 mm, d, which is 0.5 mm, and e, which is 0.3 mm.

Due to the above 3D printer (1), by applying the width light amount information corresponding to the object width less than the preset width to expose each object, uniform curing is achieved throughout the exposure image, so the molding quality of the molding can be improved. have.

By allowing the object to be exposed according to the area light amount information, the exposure can be performed by adjusting the light amount according to the area of each object, so that the entire exposure image can be cured more uniformly.

5 is a control block diagram according to an embodiment of the present invention. Previously, the description will be made except for the configuration described above in FIG. 2 . The 3D printer 1 of the present invention includes a mold plate elevating driving unit 52 . The control unit 70 controls the molding plate elevating driving unit 52 to raise or lower the molding plate 32 .

The 3D printer 1 according to the present invention not only stacks the unit molding layers by intermittently raising or lowering the molding plate 32 as described above, but also unit molding while the molding plate 32 is continuously raised or lowered. It can also be employed in the continuous molding method in which the image light corresponding to the layer exposure image is sequentially changed and irradiated. In addition, although the present invention is described based on a bottom-up 3D printer 1 in which the molding plate 32 rises and stacks in a resin tank, it is also applicable to a top-down 3D printer in which the molding plate is descended and stacked. Similarly, although the present invention has been described in the embodiment in the resin bath system, it is not limited to the 3D printer 1 in the resin bath system.

FIG. 6 is an explanatory diagram illustrating a cross-section of a single object complex shape object A to which different exposure conditions for each area are to be applied, as another embodiment of the present invention.

In FIG. 6 , a cross-section of object A may be extracted into detailed object areas A-1, A-2, A-3, and A-4 through various detection methods, respectively. In order to improve the output precision, the extracted detailed object regions A-1, A-2, A-3, and A-4 are supplied with light energy under different exposure conditions, respectively.

7A and 7B are conceptual diagrams illustrating a method of extracting detailed object areas A-1, A-2, A-3, and A-4 from one cross-section of a single object A;

In FIG. 7A , virtual grid lines having positional coordinates in the exposure image of the unit shaping layer exposed through the exposure unit 40 are arranged on the shaping surface, and the virtual grid line and one cross section of the object A are matched to each other, so that the detailed object area A A method of extracting -1, A-2, A-3, and A-4 as independent objects is shown.

In detail, the virtual grid line refers to a reference line in which a plurality of unit area cells 710 are arranged in a grid structure, and a plurality of unit area cells 710 are gathered to form an area to which light is exposed or a detailed object area. The unit area cell may be all filled with a virtual circle having the maximum radius value within the detailed object area. 7A shows one of various embodiments capable of detecting a detailed object region, and the present invention is not limited in this detection method.

The virtual circle shown in FIG. 7A may be classified into Grade 1, Grade 2, Grade 3, and Grade 4 according to the size of the radius value as shown in FIG. 7B . For example, if detailed object areas A-1, A-2, A-3, and A-4 independent from the cross-sectional image of object A are extracted and the corresponding grades are identified, Grade 1, Grade 2, Grade 3, and Grade respectively It can be seen that it corresponds to 4.

In FIG. 7b , it is explained that exposure methods under different conditions are applied to the regions corresponding to Grade 1, Grade 2, Grade 3, and Grade 4.

The control unit 70 may store the width light amount information and the area light amount information for setting different light amounts according to the width and area of the object in the storage unit, or may receive it from an external device such as a server through the data receiver. The processor 70 extracts a detailed object region according to each object included in the exposure image among the 3D molding information, and uses the width or area information according to the width or area of the extracted detailed object region and the area according to the region. The exposure unit 40 is controlled so that different exposure conditions are applied.

In the case of a protruding area with a fine size corresponding to Grade 1, the amount of light can be maintained by additionally exposing surrounding pixels to prevent the area from being uncured.

In the case of the area corresponding to Grade 2, it is possible to sufficiently harden with the light energy exposed through the exposure unit 40 .

For example, if it is applied to A-1 having a fine shape under the same conditions as the area corresponding to Grade 2, molding may fail due to insufficient amount of light or it may not be possible to obtain a molded product of desired precision. Therefore, in Grade 1, the exposure time is longer or the brightness of the amount of light is higher than in Grade 2, and it can be selectively cured by adding it to surrounding pixels compared to the existing pixels irradiated with light from the A-1 area.

In the case of the area corresponding to Grade 3, the amount of light is decreased compared to Grade 2 and hardened. For example, in the case of a relatively hollow shape than the A-2 region, such as the A-3 region, the light intensity is relatively lower or the exposure time is shorter than that of the Grade 2 region, and selectively based on the center of the detailed region. Apply grayscale exposure with a certain interval width.

In the case of the area corresponding to Grade 4, it is similar to the exposure method applied to Grade 3 in a comprehensive sense, but the resin tank 60 is not damaged or the molding quality is not deteriorated due to overheating due to radical reaction occurring during the photocuring process. In particular, the exposure may be interrupted or the exposure image may be divided and exposed. For example, considering that the area A-4 has a relatively larger area than the area A-3, exposure can be performed by irradiating light lower than the light intensity of the exposure condition applied to Grade 3 or reducing the exposure time.

8 is a conceptual diagram of extracting a region A-5 from a cross section of a single object B. Referring to FIG.

The area A-5 of FIG. 8 has an intaglio shape of a fine width and corresponds to a non-exposed area, but it is difficult to form a normal intaglio shape due to overcuring due to the light scattering phenomenon of ambient exposure.

On the other hand, if the amount of exposure is forcibly reduced in order to reduce the light scattering phenomenon, proper exposure energy is not supplied to the surrounding area A-4, resulting in poor molding quality or poor dimensional accuracy of the product.

The area A-5 shown in FIG. 8 is a engraved shape with a fine width on the basis of the exposure area, but when viewed from the standard of the non-exposed area through phase change, the area A-5 is the same as the area A-1 shown in FIG. 7(b). It can be said that it is a fine protrusion shape.

In FIG. 8, in order to extract area A-5 from single object B as a single object, in the same manner as in FIGS. 7A and 7B, virtual grid lines are defined on the molding surface in the non-exposed area, and the virtual grid lines are matched to Grade 1 Arrange unit area cells of level size. At this time, it is possible to extract the area that cannot accommodate the grade 1 level radius cell, that is, the A-5 area, as a micro-width engraving, based on the non-exposed area.

As shown in FIGS. 7A and 7B , the Grade 1 exposure method based on the non-exposed area is applied to the detected area A-5. It is possible to minimize the effect of light scattering due to the light irradiated to the surrounding pixels by making the surrounding pixels not additionally exposed or gray-scale exposure applied compared to the existing unexposed pixels.

According to the present invention, an object is exposed according to the partial shape information of the unit shaping layer image, so that the exposure can be performed by adjusting the amount of light according to the area of each object, so that the entire exposure image can be cured more uniformly.

1: 3D printer 10: data receiver
20: bed 30: molding plate unit
31: molding driving unit 32: molding plate
40: exposure unit 41: exposure lamp
42: output filter 50: molding plate connection part
60: resin tank 70: control unit
72: user input unit

Claims (3)

In a 3D printer,
a data receiving unit for receiving 3D molding information of a 3D molding;
a molding plate on which a molding formed by curing and laminating a molding plane having a plurality of objects is supported;
an exposure unit for photocuring molding by exposing an exposure image including each object among the 3D molding information to the molding plane; and
Stores width light amount information on the width of the object, determines whether each object included in the exposure image among the 3D molding information has a width less than a preset width, and the width according to the determined width of the object and a control unit controlling the exposure unit to be exposed to the object by applying light amount information. The method of claim 1,
The control unit is
controlling the exposure unit to be exposed to the object by storing the area light amount information for the area of the object, and by applying the area light amount information according to the area of each object included in the exposure image among the 3D molding information Features 3D printer. 3. The method of claim 2,
The control unit is
Extracting a detailed object area from the object based on a reference line in which a plurality of unit area cells are arranged in a grid structure,
A 3D printer for controlling the exposure unit to be exposed to the detailed object area by applying the area light amount information according to the extracted area of the detailed object area.

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