JP2012056323A - Continuous generation method for manufacturing three-dimensional object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved method for manufacturing a three-dimensional object by coagulating a coagulable material by supplying a stimulus energy such as electromagnetic radiation or the like, and to provide an improved device thereof.SOLUTION: In the method for manufacturing at least one three-dimensional object 9 via a step of coagulating an optically polymerizable material 3 by exposing the inside of a building flat surface to electromagnetic radiation at the same time or almost at the same time, the three-dimensional object 9 is coagulated to the amount exceeding a designated curing depth at that point in the building direction without interrupting the supply of the electromagnetic energy during the radiation time.

Description

  The present invention relates to a method and apparatus for manufacturing a three-dimensional (3D) object by solidifying a solidifiable material under the supply of energy such as electromagnetic radiation. The coagulable material typically includes a resin that is photopolymerizable, photocurable, or otherwise solidifiable by any stimulating energy.

  Various methods have been described in the literature for constructing three-dimensional objects stepwise or layered from photopolymers or resins, in particular photocurable polymers or resins, in this regard Marshall Burns, “Automatic Fabrication— See “Improving Productivity in Manufacturing”, 1993 (ISBN 0-13-119462-3).

  For example, in a conventional stereolithography system, a support plate is provided in a container filled with a photopolymerizable or photocurable material, and a layer on the surface of the material is cured to a predetermined layer thickness using, for example, a laser scanning beam. Irradiate selectively until After curing one layer, the support plate is lowered by the thickness of the next layer and filled with new uncured material.

  In selective irradiation with lasers, where a single point of energy supply is included and the entire building area is not irradiated at once or almost at once, the individual layers are separated in order to avoid building defects and obtain the most accurate building parts possible. It must be cured and separated with the support plate. By building in layers, conventional stereolithography processes must be performed using multiple corresponding steps per layer.

  It is an object of the present invention to provide an improved method and apparatus for producing a three-dimensional object by solidifying a solidifiable material by the supply of stimulation energy such as electromagnetic radiation.

The object is achieved by the invention described in the claims.
According to a first aspect, the present invention is a method for producing at least one three-dimensional object, wherein a construction region or a part of a construction region in a construction plane is exposed simultaneously or substantially simultaneously by electromagnetic irradiation. Providing a method wherein the distance between the support plate on which the object to be produced is built and the building plane is varied during at least one exposure phase.

  According to a second aspect, the present invention produces at least one three-dimensional object through the step of solidifying the photopolymerizable material by exposing the construction plane in a simultaneous or nearly simultaneous manner by electromagnetic irradiation. A method, wherein a three-dimensional object is solidified during an irradiation time to an amount that exceeds the current specified cure thickness in the main construction direction without interruption of the supply of electromagnetic energy during the irradiation time. Provide a method.

  According to the third and fourth aspects, the present invention produces at least one three-dimensional object comprising the step of coagulating the photopolymerizable material by exposing the construction plane by electromagnetic irradiation all at once or almost simultaneously. Providing a method in which the current cure depth of the photopolymerizable material during the build time is controlled by the speed at which the support plate supporting the object to be generated moves away from the build plane To do. As an alternative to or in combination with this control, the current cure depth of the photopolymerizable material during the continuous build time is controlled by the illumination intensity of each individual pixel of the projected rasterized image mask. .

  According to another aspect, the present invention provides an apparatus for producing at least one three-dimensional object by solidifying a photopolymerizable material, wherein the construction area or a part of the construction area is constructed via electromagnetic irradiation. Electromagnetic energy is applied so that the distance between the device that supplies electromagnetic energy simultaneously or almost simultaneously, the support plate that can support the object to be generated, and the support plate and the construction plane changes during at least one irradiation time. An apparatus is provided comprising a control unit configured to control a device that supplies energy.

  According to yet another aspect, the present invention is an apparatus for producing at least one three-dimensional object by coagulating a photopolymerizable material, wherein the electromagnetic wave is electromagnetically or substantially simultaneously applied to a construction plane via electromagnetic radiation. The energy supply equipment and the 3D object solidify during the irradiation time to an amount exceeding the specified cure thickness at that point in the main construction direction without interruption of the supply of electromagnetic energy during the irradiation time An apparatus comprising a control unit configured to control a device that supplies electromagnetic energy is provided.

  By applying the method of the present invention, the photopolymerizable material is photopolymerized without interruption through electromagnetic irradiation and is formed from the photopolymerizable material, including separated layers, dots, and filaments of material. It becomes possible to provide at least one three-dimensional object that is continuously constructed without forming any resulting discretely polymerized structural elements.

  As used herein, the term “at least” one three-dimensional object means that the method of the present invention allows a complete 3D object, only a portion of a complete 3D object, or multiple substructures of a complex object, simultaneously or It means that it can be used to form a plurality of 3D objects or a plurality of partial 3D objects at the same time or at different times, including the case of forming at different times. The term “partial object” or “partial structure” does not only mean the desired structure of the final three-dimensional object, but is only generated by the process and included in the final three-dimensional object. It also means a support object or a support structure without a gap.

Description of the invention and its advantages

  Within the framework of the present invention, it can be surprisingly found that a complete layered generation of a three-dimensional object can be dispensed with, in contrast to conventional stereolithography techniques, and that a layer-independent process is carried out. It has been found that the device can be configured to accommodate it.

  Prior art conventional methods and apparatus may be improved by solving the problem with the present invention and its preferred embodiments, and the features described subsequently may be provided, or the advantages mentioned respectively, alone. Alternatively, it can be achieved in combination.

  During the continuous (non-interrupted) exposure process, i.e. during the at least one irradiation phase and preferably throughout the construction process of the three-dimensional object, the distance between the support platform or support plate for the three-dimensional object and the construction plane is continuously That is, it can be changed without interruption.

  Thereby, according to the present invention, in a process having a plurality of steps, it is not necessary to solidify the material by forming a layer for each step. If some slight boundary layer formation still occurs due to possible interruptions in irradiation, such boundary formation may be performed, for example, for each irradiation plane used for various structural sections of a three-dimensional object. By limiting to various illumination area changes or various bitmap changes, the number can be minimized or eliminated altogether.

Furthermore, the construction process is accelerated by the present invention.
By avoiding the layer structure, it is further possible to omit the generation of thin-layer image data.

  The continuous change of the spacing according to the invention can be achieved by moving the support or support plate away from the construction plane and / or the filling level of the construction plane or photopolymerizable material, depending on the desired embodiment. Alternatively, it is realized by moving away from the support plate. The latter can be implemented by raising the construction plane relative to the support or support plate or by increasing the filling level of the photopolymerizable material when illuminated from above the support or support plate. . It is preferred according to the invention that the support base or the support plate be moved away from the preset construction plane.

  According to the present invention, when the spacing is continuously changed during the irradiation process, and preferably throughout the construction process of the three-dimensional object, the structural steps in the main construction direction (usually the vertical Z direction) are conventional. Unlike the laminar process, it can be reduced, advantageously minimized, and can even be adjusted to provide a continuous gradual change and eliminate any structural steps. Unlike conventional layered processes, individual structural steps in the Z direction defined by predetermined layers are not required. Rather, the structural step in the Z construction direction can be flexibly controlled according to the construction situation, can be optionally variably adjusted, or realized in the form of a continuously gradual change structure I can even do that.

  The three-dimensional object can be solidified or grown in the main build direction (usually the Z direction) during each irradiation phase and optionally without interrupting the supply of electromagnetic energy throughout the build process. As a result, the corresponding continuous growth in the main construction (Z) direction of the solidifiable material during the irradiation phase is applied and / or used by the electromagnetic energy (irradiation) supply used in conventional layered solidification. Can proceed beyond the normal cure depth defined by the polymerizable material to be obtained. Thus, the process according to the invention makes it possible to significantly extend the irradiation phase over conventional layered irradiation and to obtain a continuous and uniform (extended) cure depth during those phases, The cure depth exceeds several times the conventional layer cure depth, usually in the micrometer range. The continuous and uniform (expanded) cure depth that can each be achieved by the irradiation phase according to the invention is, for example, clearly greater than 1 mm, preferably greater than 2.5 mm, more preferably greater than 1 cm. Depending on the case, it may be in the range of more than 10 cm. If desired, the entire three-dimensional object can even be subjected to large, continuous (uninterrupted) and uniform solidification by avoiding substantial interruptions in irradiation.

  By means of a continuous process independent of the layers, according to the invention it is possible in particular to influence and control the current cure depth of the photopolymerizable material. Adjusting the speed at which the support or support plate supporting the object to be generated moves away from the construction plane and adjusting the irradiation intensity (gray value or color value) of the pixel, either alone or in combination, can be used to control the curing depth. It becomes a specific means to control.

  The preferred uninterrupted (continuous) process of supplying electromagnetic energy helps to improve the operability of the projection unit and / or simplify the structure of the entire apparatus. Furthermore, it is possible to reduce the amount of data required to construct a three-dimensional object, thereby reducing the calculations required for it and thereby improving the calculation efficiency.

Each of the methods and apparatus according to the present invention may include, on the one hand, pre-determined, optionally multiple, uninterrupted illumination phases to construct the entire three-dimensional object, while on the other hand illumination of the construction plane. It can be designed flexibly so that it can include at least one phase that does not or is reduced. The interval change described above may occur during the uninterrupted irradiation phase (s) and optionally during at least one phase in which the construction plane is not illuminated or the dosage is reduced. Also implemented. At least one phase that reduces the dose of the construction plane and optionally does not irradiate is potentially, but not necessarily, used for, for example, one or more of the following steps or situations. That is,
-When changing the irradiation cross-section area in the construction plane,
-When changing the exposure mask for a cross-sectional area,
When using a shutter and / or when using a smoothing element such as a wiper.

  When applied, the duration of at least one phase without irradiation of the building plane can each be short, preferably very short, for example up to 10 s, preferably up to 1 s, more preferably Up to 10 ms, especially up to 1 ms.

  However, another advantage of the present invention is that it is not always necessary to interrupt the irradiation, for example, it is possible to continue the irradiation during the aforementioned process or situation.

  The spacing change can be variably adjusted during the construction process. In this way, the degree of curing can be controlled preferably by the moving speed in the main construction direction such as the Z direction.

  Due to the continuous movement process in the main construction direction, such as the Z direction, device components such as wipers can be used independently of the layers. Unlike conventional construction modes, the components of the device are different from the construction process or other three-dimensional objects that are more convenient for the created three-dimensional object, such as the Z-direction distance where the cross-sectional area of the horizontal (XY) construction plane is the same. It can be used by considering the embodiment.

  (XY) It is possible to perform an optimized irradiation process in which no new exposure mask is generated or used until the cross-sectional area changes along the Z-direction height or the Z-direction position. .

  As a result, the irradiation process can cope with how high the resolution in the Z direction is with respect to the exposure mask that is successively projected according to the moving Z direction height or the Z direction position.

  In order to avoid defects during the construction process, especially when performing electromagnetic irradiation such as exposure, the construction area to be irradiated, that is, the XY cross-sectional area or XY partial cross-sectional area of the construction plane to be irradiated at that time, And preferably it is important to irradiate the entire construction area all at once or almost simultaneously.

  This can be realized by a projection system using mask exposure that reliably performs simultaneous irradiation. A particularly preferred projection system for generating an exposure mask is based on what is known as DLP® / DMD®.

  An alternative to mask exposure is a projection system in which a static image or a nearly static exposure image is generated, thereby achieving nearly simultaneous illumination, eg, scanning a desired construction area of the construction plane to be illuminated quickly enough. Resulting by irradiating with a laser-based projection system. Nearly simultaneous illumination, or sufficiently fast scanning, is usually achieved when an image is generated that is stationary or nearly stationary to the human eye. Appropriate ranges of image frequencies or update rates to produce images that are stationary or nearly stationary to the human eye are known from video and projection techniques and can be applied accordingly. . An example of a projection system that uses an image that is stationary to the human eye is described in WO 01/14125 A1, but the present invention provides such a projection system to achieve nearly simultaneous illumination. It is in no way limited to use.

  As the photopolymerizable or coagulable material according to the present invention, for example, if it can be solidified by supply of stimulation energy such as electromagnetic irradiation such as UV irradiation, visible light, IR irradiation, electron beam irradiation, X-ray irradiation, It can be any material that can contain a resin and optionally further components. Preferably, the material is polymerizable by UV irradiation and / or visible light, such as at least one ethylenically unsaturated compound (including but not limited to acrylic acid (methacrylic acid) monomers and polymers) and / or at least A material containing a resin having one epoxy group can be used as such a material. Suitable other components of the solidifiable material include, for example, but are not limited to inorganic and / or organic fillers, colorants, viscosity control agents.

  As the smoothing element, a wiper, a bar or blade, a roll, a sliding body, or the like can be used. A “doctor blade” method, in which the vacuum vessel acts as an auxiliary material reservoir and “sweeps” the surface from end to end, or the well known “curtain coating” method is preferred.

  The system according to the present invention has separate polymerized structural elements that can be formed from layers, dots, or filaments of photopolymerizable material, formed by photopolymerization with continuous material construction by electromagnetic irradiation of the photopolymerizable material. A three-dimensional object can be provided. The three-dimensional object provided by the present invention thus differs from other three-dimensional objects obtained by other free-form construction techniques, particularly large-scale photopolymerization, in which the photopolymerizable material is cured separately. It is negligible to have or not have an interface between the parts. Unlike traditional stereolithography or other conventional freeform construction techniques such as selective laser sintering, impact particle manufacturing, melt layering, 3D printing, 3D plotting or other rapid modeling processes 3D objects without separation layers or individual material filaments or dots can be provided via an uninterrupted (continuous) stereolithography process that avoids the formation of layers, filaments or dots. The technique according to the invention is particularly suitable for realizing three-dimensional objects with various cross-sectional areas in the continuous material construction direction.

  The invention will now be described by way of example and not limitation with reference to the drawings.

FIG. 2 is a basic schematic view of a method or apparatus (cross section) according to a preferred embodiment of the invention, in which irradiation is carried out from the top. FIG. 2 is a basic schematic diagram of a method or apparatus (cross-section) according to a particular operation of an embodiment, in which the smoothing elements are rocking simultaneously during the irradiation phase. FIG. 6 is a schematic diagram illustrating details of a method or apparatus (left is a cross-sectional view, right is a perspective view) according to another preferred embodiment of the present invention.

  The structure of FIG. 1 schematically shows in cross-section an embodiment of the device according to the invention for a rapid modeling process based on photocoagulation using laser or mask exposure by the projection unit 1, below the projection unit. The liquid material 3 containing a photopolymer (photopolymerizable resin) is supplied into the container 7, and the level of the liquid material 3 is the surface 5. Here, the surface 5 of the liquid material 3 forms the projection surface of the projection image as it is, thereby defining the construction plane. The other liquid or at least the flowable material 3 can be formed by the liquid photopolymer itself or a mixture or solution of photopolymer with the carrier material. A vertically movable support 8 is provided in the container and thus in the liquid material. The position of the support 8 in the Z-axis direction is always known and can be controlled either via the control unit 11 by an encoder or by using a motor (M) 2. In this embodiment, the filling level of the material during the build process is kept constant. The filling level and thus the position of the surface 5 in the Z-axis direction can be determined by the filling level sensor 6 and readjusted via a reservoir 10 containing additional liquid polymer material 3.

  The support 8 (with the generated object) is continuously lowered from the material surface and the cure depth of the selectively irradiated photopolymer can be controlled by the moving speed. The wiper 4 removes the convex or concave curvature (eg positive or negative meniscus) of the construction plane material that may occur during continuous production and reshapes the flat or essentially flat construction plane or material surface To do so, it can be moved or positioned horizontally at a predetermined height above the construction plane or material surface.

  During the continuous movement of the support plate, the irradiation can be interrupted, for example, during a wiper swing or during the generation of a new projection image. The complete interruption or partial weakening of the illumination is preferably performed by a shutter, for example via an electromechanical element (not shown) arranged in the illumination path, or by using a projection system. This can be achieved by changing or adjusting the parameters and / or contrast parameters.

  In this preferred embodiment, the support plate continuously moves away from the build plane at a constant or variable speed during the entire build process. Here, the change in the movement speed affects the degree of curing of the photocuring resin and can therefore be specifically controlled / adjusted during the construction process, for example to achieve overexposure or half-exposure on a part of the structure. .

  By lowering the generated object on the support plate away from the construction plane and below the material surface, another new material that has not yet been photopolymerized flows into the object from the outside and fills the lowered part.

This reflow or material supply can be assisted periodically or alternately by wipers.
In construction planes that may be caused by continuous production, again using alternating or periodic horizontal movement or placement of bars or blades, wipers, or sliding bodies at a predetermined height on the construction plane or material surface The convex or concave curvature (eg, positive or negative meniscus) of the material can be removed and a flat or essentially flat construction plane or material surface can be recreated.

  When irradiation is interrupted, for example due to the formation of new images and / or movement of the wiper, the speed of movement of the support plate can be minimized.

  Specific operating conditions are shown in FIG. 2 for the corresponding processes and apparatus corresponding to those of FIG. 1, each with corresponding reference numerals for the same components shown, but FIG. 4 specifically illustrates the characteristic of alternating or periodically oscillating at desired times during the irradiation phase, thereby smoothing the material surface in the construction plane. This operation allows a continuous process without interruption, optionally eliminating short exposure interruptions that may be required for new imaging or new exposure mask generation. To do. However, if necessary, the operation according to FIG. 2 can also be used with optional interruption of the irradiation and additional wipers in between.

  The embodiment shown in FIGS. 1 and 2 can be modified. For example, as shown in FIGS. 1 and 2, instead of defining the surface 5 of the photopolymer material 3 as a construction plane, a reference plane made of a suitable transparent material is provided in the construction plane and an exposure image is projected onto the plane. be able to. Furthermore, in addition to or instead of movement of the support 8, a change in the distance between the support plate and the construction plane can be realized by increasing the level (of the surface 5). This rise is monitored and controlled by the filling level sensor 6, the material storage tank 10 and the control unit 11.

  Further, as shown in FIG. 1, instead of irradiation from above, an upside down structure can be formed. In this case, irradiation is performed from below, and the support plate disposed above is raised. In this modified embodiment, the filling level sensor 6 and the wiper 4 can be omitted.

  In FIG. 3, by means of a detailed view and referring to a more preferred embodiment, the present invention enables a highly variable yet simple technique for producing a three-dimensional object, independent of layers or without layers. Indicates that Similar to FIGS. 1 and 2, reference numerals 8 and 9 respectively indicate a support descending in a direction away from the construction plane 5 and a three-dimensional object continuously generated thereon. Cross sections 1 ′, 2 ′, 3 ′ and 4 ′ each show a specific construction cross section of the three-dimensional object 9. An image forming bitmap 12 of the image forming unit 1 is shown schematically for each of the corresponding cross-sections 1 ', 2', 3 'and 4'. In principle, a relatively small number or optionally only one bitmap 12 is required for the cross-sections 1 ′, 3 ′ of the three-dimensional object 9 whose perimeter is virtually unchanged, The exemplary relevance that a relatively large number of bitmaps 12 are required for cross-sections 2 ', 4' with varying perimeters is thus shown. The speed of movement of the support can also be selectively adjusted for each cross section to produce cross sections that are substantially unconfined by the layers. For example, a relatively high moving speed can be selected for structurally simple sections 1 ′, 3 ′, while a relatively low moving speed can be selected for structurally complex sections 2 ′, 4 ′. Can be selected.

  The above description of the preferred embodiments is merely illustrative for purposes of explanation, rather, any variations and combinations of the described features and advantages are possible within the scope of the invention.

Claims (20)

  A method of producing at least one three-dimensional object through a step of solidifying a photopolymerizable material by exposing the construction plane by electromagnetic irradiation simultaneously or substantially simultaneously, wherein the three-dimensional object is irradiated A method in which, during time, the supply of electromagnetic energy during the irradiation time is solidified to an amount exceeding the specified curing depth at that time in the main construction direction without being interrupted.   The method according to claim 1, wherein a distance between a support supporting the object to be generated and the construction plane is variably changed. The method of claim 2, wherein the support continuously moves away from the building plane at a variable speed or a combination of constant speed and variable speed.   The method according to claim 1, wherein the material supply of the unpolymerized photopolymerizable material is automatically performed by flow.   The method according to any one of claims 1 to 4, wherein the material supply of the unpolymerized photopolymerizable material is carried out periodically or alternately by means of blades or wipers.   The convex or concave curvature of the photopolymerizable material that occurs in the construction plane during the continuous generation of the three-dimensional object causes the smoothing element to move horizontally or cyclically at a predetermined height above the construction plane. 6. A method according to any one of the preceding claims, wherein the method is removed by placing or placing to reshape a flat or essentially flat material surface.   A method for producing at least one three-dimensional object comprising a step of solidifying a photopolymerizable material by exposing a construction plane by electromagnetic irradiation simultaneously or substantially simultaneously, wherein said photopolymerizability during construction time A method in which the current curing depth of the material is controlled by the speed at which the support supporting the object to be produced leaves the construction plane.   A method for producing at least one three-dimensional object comprising the step of solidifying a photopolymerizable material by exposing the construction plane in a simultaneous or almost simultaneous manner by electromagnetic irradiation, wherein the photopolymerization during a continuous construction time A method in which the current cure depth of the active material is controlled by the illumination intensity of each individual pixel of the projected rasterized image mask.   The current cure depth of the photopolymerizable material during the build time is additionally controlled by controlling the rate at which the support supporting the object to be generated moves away from the build plane. The method according to claim 8.   The method according to claim 1, wherein the exposure of the photopolymerizable material is carried out by mask exposure through a projection system.   The method of claim 10, wherein the projection system for generating a mask exposure is based on DLP / DMD technology.   At least one of the supply of electromagnetic radiation to the construction plane is interrupted while one or more exposure phases and the spacing between the support supporting the object to be generated and the construction plane are further changed The method according to claim 1, comprising one phase.   13. A method according to claim 12, wherein during the interruption of the supply of electromagnetic radiation to the construction plane, the speed of moving the support away from the construction plane is kept to a minimum value. An apparatus for producing at least one three-dimensional object by solidifying a photopolymerizable material,
A device that supplies electromagnetic energy to the construction plane all at once or almost all at once via electromagnetic irradiation, and the three-dimensional object is not irradiated during the irradiation time. An apparatus comprising: a control unit configured to control said device supplying electromagnetic energy so that it is solidified to an amount in the construction direction that exceeds a specified curing depth at that time.   15. The apparatus of claim 14, further comprising a smoothing element that smoothes the construction plane periodically or alternately.   16. Apparatus according to claim 14 or 15, wherein the device for supplying electromagnetic energy simultaneously or substantially simultaneously comprises a projection unit for generating a projection mask.   The apparatus according to claim 16, wherein the projection unit for generating a projection mask is based on DLP / DMD technology.   The electromagnetic wave is controlled so that the control unit interrupts the supply of electromagnetic energy to the building area in the building plane while the support supporting the object to be generated is continuously moving away from the building plane. 18. Apparatus according to any one of claims 14 to 17, configured to control the device or shutter for supplying energy. A filling level sensor for determining a filling level of a container that can be filled with the photopolymerizable material;
A storage tank for an additional photopolymerizable material;
The control unit is configured to control the reservoir to either pour photopolymerizable material into the container or withdraw it from the container according to information received from the fill level sensor. ,
The apparatus according to any one of claims 14 to 18.   A three-dimensional object formed from the photopolymerizable material by photopolymerizing the photopolymerizable material without interruption through electromagnetic radiation, and may include separate layers, dots, and filaments of the material A three-dimensional object constructed continuously without forming any separate polymerized structural elements.

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