Patent Application
20240116243
The present invention relates to a 3D printer based on the principle of the SLA/DLP process.
3D printers based on the principle of the SLA/DLP (SLA: Stereo Lithography Apparatus) process can currently only produce shaped parts from one material. 3D printers available in the state of the art do allow the use of different materials. However, this requires the material in the print reservoir to be replaced or the complete reservoir including material to be replaced. This approach allows only a serial processing of the process steps. The device and the process of the invention are particularly effective in a CLIP process (Continous Liquid Interface Production)—i.e. in a continuous process in which a so-called “dead zone” is built up from which the shaped part can be built up. In this process, a “non-polymerizable zone (dead zone)” is chemically created between the contact surface of the shaped parts on the build platform and the transparent base, from which the shaped parts are produced from a curable composition in the CLIP process.
Therefore, it is an object of the present invention to provide an apparatus and method that allows simultaneous printing of different materials in the same 3D printer.
The problem is solved by a device for the layer-by-layer generative production of at least two three-dimensional shaped parts, each consisting of at least one separate composition curable by means of radiation, in particular two to n shaped parts, comprising
Preferably, the bottom is provided with a fluorine-containing coating or fluorine-containing film on the inner surface facing the process chambers. The bottom can be segmented and be a separate bottom for each process chamber. The bottom can thus be designed with special radiation filters for each process chamber depending on the radiation-curable composition. In an alternative, the bottom can comprise a transparent plate on which a silicone layer and/or film is arranged for each process chamber. The advantage of this segmentation is that, in the event of damage, only one foil in the affected process chamber needs to be replaced. The pressure trough can comprise two to n, with n equal to 3 to 500 process chambers, in particular 3 to 150, preferably 10 to 150, particularly preferably 50 to 250.
Alternatively, it may be preferred that one tray with a transparent bottom or transparent tray is inserted in each of one to n-th process chambers. The trays can be locked into place in the process chambers or magnetically fixed in the process chambers. Curable compositions may be placed in said trays. Alternatively, trays may be provided as sealed kits comprising curable compositions. Further, trays may be provided as a horizontal array of trays comprising one or different curable compositions as sealed kits.
With the apparatus and process according to the invention, one to n shaped parts per process chamber and, in each of the at least second to n-th process chambers, one to n shaped parts per process chamber can be produced simultaneously from each of the curable compositions by means of radiation curing. The particular advantage of the invention results from the arrangement of a pressure trough with two to n process chambers in a device with a radiation source emitting radiation over an area, in particular with a projection unit, for simultaneous radiation exposure of the bottom of the process chamber filled with a composition selected from one to n process chambers.
The device preferably comprises a device for homogenizing the beam quantity distribution of the radiation source and/or the beam quantity distribution of the beam deflection device, which serves to produce a homogenized beam quantity distribution and has an arrangement of a two-dimensional radiating radiation source, an area light modulator and an optical system, in particular a lens system forms the optical system. The device for homogenizing the beam quantity distribution is preferably provided below the exposure field on which the pressure trough can be arranged in the device. The device for homogenizing the beam quantity distribution is suitable for homogenizing the two-dimensionally radiating beam source and for imaging the beams only onto selected process chambers, in particular onto the process chambers filled with a composition. In a very particularly preferred device and method, simultaneous exposure of a selection of process chambers, in particular the process chamber filled with a radiation-curable composition, is possible.
The task of the present invention is solved in an alternative by an apparatus for the layer-by-layer generative production of at least two three-dimensional shaped parts, each from at least one separate composition curable by means of radiation, comprising
In one embodiment, a print well may be a part of a basin module of a 3D printer. A preferred print tray is inserted into a device without a basin module. The print trough contains—in particular separated by one or more separating plates—one or more process chambers in which the actual 3D printing process takes place. The separating plate can be reversibly fixable vertically in the bottom of the printing tray, in particular plug-in, magnetically fixable and/or snap-in, e.g. in transparent silicone lips, which can be arranged on the bottom of the printing tray. This allows each process chamber to be configurable in terms of size and can be adapted to the printing process. The number and size of the process chambers are thus variable. The print trough preferably comprises the entirety of the process chambers.
The bottom of the pressure trough is preferably made of a transparent material so that the radiation source, with whose beams curable compositions are cured, can be positioned below the bottom. The irradiation takes place through the bottom of the trough. Here, the bottom may preferably be provided as a continuous large irradiation window across all process chambers or a single irradiation window for each process chamber. Alternatively, the bottom of the tank can be formed by a transparent plate on which trays with transparent bottoms, preferably transparent bottoms made of transparent films, can be placed to form the process chambers.
The walls of the pressure trough and optionally engageable separation plates are preferably coated with silicone to provide effective sealing of the individual process chambers from each other so that different compositions can be filled into the process chambers. In one embodiment, the bottom of the pressure trough is 100% transparent radiolucent material. In particular, the transparent radiolucent material can be an inorganic glass, in particular quartz glass, or also a transparent polymeric material, such as polymethyl methacrylate (PMMA), polycarbonate (PC) or polyimide.
It is preferred that the two to n-th process chambers, in particular with n equal to 20 to 200, of the pressure trough are formed by vertical separating plates, optionally transparent separating plates, in the pressure trough.
Furthermore, it is preferred if the pressure trough with the bottom facing the radiation source and/or radiation deflection device is formed by at least one transparent
Preferably, the coating is an anti-stick coating, in particular the coating comprises fluorine-containing polymers, especially preferred are fluorine and polyalkylene oxide containing polymers. Further preferably, the glass is selected from SiO2 glass, borosilicate glass, fused silica, annealed glass. A preferred polymer plate is formed from a transparent polymer comprising polycarbonate, polymethyl methacrylate (PMMA) or polyimide.
It is further preferred if the film is preferably a film permeable to gases, in particular nitrogen and/or oxygen. Particularly preferred films or coatings or also silicones comprise, as fluorine-containing polymers, polytetrafluoroethylene, fluorine-containing polyalkylene oxides or other partially fluorinated or perfluorinated hydrocarbons known to the skilled person and fluoroalkyl compounds containing partially fluorinated or perfluorinated oxygen atoms, in particular films permeable to nitrogen and/or oxygen.
According to an alternative, it is preferred if the bottom of the pressure trough or a bottom of the respective process chamber is formed by:
In particular, the bottom of the pressure trough can integrally comprise a first bottom in a first process chamber, a second bottom in a second process chamber, and an n-th bottom in n-th process chamber. Alternatively, the bottom of the pressure trough may be segmented, wherein the first, second through n-th bottoms may form the bottom of the pressure trough from individual segments. Preferably, the transparent bottom of the pressure trough is integral to the entire pressure trough. Likewise, it is preferred if the transparent bottom of the pressure trough integrally comprises the first, second to n-th bottoms of the process chambers.
Depending on the proportion of transparent material at the bottom of the pressure trough, at least one process chamber to several process chambers of the pressure trough can be irradiated simultaneously with a radiation source positioned below the bottom, so that in one embodiment the different curable compositions in the different process chambers can be cured simultaneously with the same radiation source. In another embodiment, an individual irradiation window is provided for each process chamber, in particular with a separate radiation source, preferably with a projection unit. Thus, a device for simultaneous additive manufacturing of components made of different curable compositions is provided in an advantageous manner.
3D printing (also 3D printing), also known as additive manufacturing, additive manufacturing (AM), generative manufacturing or rapid technologies, is a comprehensive term for all manufacturing processes in which material is applied layer by layer to create three-dimensional objects (workpieces). In this process, the layer-by-layer build-up is computer-controlled from one or more liquid or solid materials according to specified dimensions and shapes (cf. CAD). Physical or chemical hardening or melting processes take place during the build-up. Typical materials for 3D printing are plastics, synthetic resins, ceramics and metals.
Head-over-head irradiation of the curable compositions with jets means that the curable composition is irradiated with jets from below, through the pressure trough bottom, and thereby cured. This results in a bottom-side bond of the shaped part to be formed from the curable compositions to the underside of the build platform or underside of the forming shaped part. Such head-over-head impingement with radiation or beams are achievable, for example, by arranging the source of radiation or beams below the pressure well arrangement. Alternatively, it is also possible to mount a mirror arrangement below the pressure trough arrangement as a radiation deflection device, via which the radiation is suitably introduced through the transparent bottom of the pressure trough. Also, at least two, in particular a plurality of radiation sources and/or radiation deflection devices may be provided. In one embodiment, a radiation source and/or a radiation deflection device is associated with each process chamber.
By means of radiation exposure, the curable compositions can be cured, depending on the choice of starting components, e.g. under polymerization, polycondensation, polyaddition and/or thermal curing.
Radiation-curable compositions, such as those used in stereolithography, are well known to those skilled in the art and are also commercially available. These are, for example, monomer mixtures containing, for example, acrylates, which can be cured by radiation, in particular in the presence of activators and/or initiators, via a polymer reaction, usually a free-radical polymerization. These curable compositions can be used both in liquid and in viscous, for example pasty, form. The curable compositions used with the device according to the invention can differ, for example, in their type, composition and color or coloring (shades). Suitable curable compositions may, for example, be provided with fillers, colorants, flow improvers and/or other additives.
Radiation includes the light spectrum visible to humans as well as ultraviolet and infrared radiation.
Different curable compositions can also be deposited in the at least two process chambers open at the top.
A device according to the invention is preferably a device for photopolymerization, in particular according to DIN EN ISO/ASTM 52900, VPP Vat Photopolymerization.
In a further embodiment, it is provided that the device is one for stereo lithographically producing at least one three-dimensional shaped part from at least two curable compositions and/or that the apparatus is one for digitally light processing at least one three-dimensional shaped part from at least two curable compositions.
Stereolithography processes belong to the rapid prototyping processes. Rapid prototyping processes are three-dimensional printing processes. In this case, radiation is used to polymerize (harden) monomers or compositions comprising a mixture of monomers, preferably with UV radiation. Starting from a 3D model in STL format, this is possibly provided with a support structure, also called a support, in order to increase the stability in the bath on the build platform. The model thus obtained is then digitally divided into individual layers, the process is called slicing. The individual layers are read into a machine control system, where they are adjusted accordingly. The machine control system regulates the sequence of movements and the irradiation process.
Digital Light Processing (DLP, English) is a projection technology developed by the US company Texas Instruments (TI) and registered as a trademark, in which images are generated by modulating a digital image onto a light beam. In this process, the light beam is split into pixels by a rectangular array of movable micromirrors and then reflected pixel-by-pixel either into or out of the projection path. The heart of this technology, the component that contains the rectangular array (matrix) of mirrors and their control technology, is called a DMD
In a DLP process, a surface is irradiated via a DLP chip (digital light processing, a micromirror reactor) with LED technology and an optical power of 0.5 to 100 watts. The DLP process is only known as a static process as well as a scrolling process. The radiation source is not moved during the irradiation phase (static) and irradiates new resin layers to be polymerized in still images each time.
The device further comprises an arrangement comprising an area-emitting radiation source, an area light modulator, and the optics, which is preferably a lens system. The radiation source may comprise a UV laser or a projector. For example, the projector may be a projector with DLP (Digital Light Processor) technology from Visitech AS. Preferably, a micromirror reactor is used with DLP technology. The optical power of the UV radiation source is preferably in the range of 0.5 to 100 watts. Preferred wavelengths are in the range of 340 nm to 500 nm, in particular the UV-radiation source has maxima in the range of 340 nm to 500 nm.
Preferred micromirror reactors may include microscanners and area light modulators, preferably an area light modulator. A particularly preferred radiation source, especially beamers, comprises a matrix-shaped array of tiltable micromirrors arranged as a plurality of driveable micromirrors arranged in rows and columns. A preferred area light modulator is a digital micromirror device (DMD).
In a further embodiment, it may be provided that the bottom of the pressure trough facing the radiation source and/or radiation deflection device and having the at least two process chambers additionally comprises highly transparent silicone and a polymeric layer containing fluorocarbons in addition to the transparent material comprising glass, in particular quartz glass, wherein the glass is formed as a glass pane, wherein the highly transparent silicone is formed as a layer on the glass pane on the side facing away from the radiation source and/or radiation deflection device, wherein the polymeric layer containing fluorohydrocarbon is arranged as a porous membrane on the side facing away from the radiation source and/or radiation deflection device on the highly transparent silicone layer.
As a result, the bottom of the pressure trough is permeable to the radiation. In one embodiment, the entire pressure trough bottom constitutes an irradiation field. In another embodiment, an irradiation field is provided for each process chamber of the pressure trough.
Quartz glass, also known as silica glass, is a glass which, in contrast to the more common glasses, does not contain any admixtures of soda or calcium oxide, i.e. it consists of pure silicon dioxide (SiO2).
Silicones (also silicones), chemically more precisely poly(organo)siloxanes, is a name for a group of synthetic polymers in which silicon atoms are linked via oxygen atoms. Molecular chains and/or networks can occur. The remaining free valence electrons of the silicon are saturated by hydrocarbon radicals (usually methyl groups). Silicones thus belong to the group of organosilicon compounds. Because of their typically inorganic skeleton on the one hand and the organic radicals on the other, silicones occupy an intermediate position between inorganic and organic compounds, especially between silicates and organic polymers. In a sense, they are hybrids and exhibit a unique range of properties unmatched by any other plastic.
Highly transparent silicones are a special type of silicone elastomers that are used primarily in the optical sector. They belong to the LSR (liquid silicone rubber) materials, which are characterized above all by their low viscosity, and thus the possibility of processing the silicone by injection molding. In addition to the types that can be injection molded, there are also those that are suitable for potting. These have an even lower viscosity.
The greatest advantage for optical applications is offered by the silicone in terms of its resistance behavior. For example, it remains stable over a wide temperature range (−40° C. to +150° C.), on the one hand in its mechanical behavior, and on the other hand also in its optical behavior, i.e. compared to other plastics, silicone does not yellow over time. In optical applications in particular, yellowing must be avoided at all costs, as this leads to severe functional impairment and even functional failure. Another advantage of silicone over other materials is its elasticity. This can be exploited in headlamps, for example, to influence light conduction by deformation and thus generate dynamic bend lighting, among other things.
Furthermore, optical components made of silicone are significantly lighter than their glass counterparts due to their lower density. Silicone also offers manufacturing advantages. The processes are easier to handle, low cycle times can be realized and production can be carried out to very tight tolerances. In addition, the flow behavior of the material allows very complex geometries to be molded.
The polymeric layer containing fluorocarbon comprises polytetrafluoroethylene (abbreviation PTFE, occasionally also polytetrafluoroethene), which is an unbranched, linear, semi-crystalline polymer of fluorine and carbon. PTFE belongs to the class of polyhaloolefines, which also includes PCTFE (polychlorotrifluoroethylene). It belongs to the thermoplastics, although it also has properties that require processing more typical of thermosetting plastics.
In a further embodiment, the at least two process chambers may be separated from each other by at least one separating plate (partition wall), wherein the at least one separating plate is at least partially coated with a fluorine-containing coating and/or with silicone, wherein in particular the walls of the pressure trough are coated on the inside with a fluorine-containing coating and/or with silicone, so that the inner walls of the at least two process chambers each have a fluorine-containing coating and/or silicone layer.
By coating the walls of the process chambers with silicone, the curable mixtures can advantageously be detached from the walls of the process chambers after completion of the three-dimensional object.
Accordingly, the pressure trough arrangement may have a plurality of process chambers, in particular having substantially square or rectangular cross-sectional bottom surfaces, with adjacent process chambers preferably being separated from each other by a common partition.
In a further embodiment, it is provided that the at least one separating plate is reversibly engageable, in particular vertically, in the pressure trough.
As a result, the individual process chambers can be configured individually in terms of size in an advantageous manner. The number of process chambers is variable. Adaptation can be made to the shaped part to be printed. Process chamber and part-building platform can be assigned to each other. In one embodiment, the bottom of the pressure trough has sealing means, in particular, transparent silicone lips, rubber seal, sealing tape and/or flexible plastic, into which the separating plates can be pushed vertically. The sealing means serve to seal the separating plates at the bottom of the pressure trough.
In another embodiment, the build platform is segmented into punches, wherein the punches are movable, in particular along their longitudinal axis, in particular in the direction of the radiation source and/or beam deflector.
In an alternative, the build platform can be segmented into punches, with one punch being assigned to each process chamber. The punches can be static or manually movable along the z-axis, in particular in the printing direction of the material buildup. Likewise, in an alternative, the punches can be digitally controlled and movable along the z-axis by means of e-motors. Likewise, the build platform can be segmented and assembled for the application. In this case, one segment of a build platform can be individually selected for each process chamber and the selected segments can be assembled to form a build platform. Thus, it is also an object of the invention to provide a build platform that is composed of build platform segments and, in particular, can be individually assembled for different printing processes.
In this way, several build platforms can be realized simultaneously in an advantageous manner, each of which is matched to the size and shape of the respective process chambers.
Different compositions, i.e. different materials, can be cured simultaneously on the various part-building platforms in the associated process chambers. The shaped part to be formed from the different curable compositions is bonded simultaneously to the underside of the different part-building platforms in each process chamber if the irradiation times of the process chambers are identical.
The punch-like platform units in the head-over-head exposure device of the invention advantageously provide an automatic ejection system by selectively retracting or extending the individual punches of the build platform for detaching the printed object.
The number of punches can be n=2 to, for example, n=100 or n=200.
In this context, “movable” means that the punches can be moved down (toward the bottom of the pressure trough) or up (away from the pressure trough) or tilted from the build platform plane.
In a further embodiment, it is provided that each of the movable punches is individually controllable by a processor or at least one group of punches is individually controllable by a processor.
Each of the punches is individually controllable independently of the other punches. In one embodiment, the punches are arranged in a matrix and the punches are controlled via a matrix control. In this case, the control of a punch relates to the extent to which a punch is moved out of a defined zero position into a position calculated from the STL data, and thus derivable from the CAD data of the 3D model.
The device according to the invention for the layer-by-layer generative production of three-dimensional shaped parts further generally comprises a data memory for storing data, in particular CAD data, which represent a three-dimensional object. Such data memories and the implementation of suitable data sets for three-dimensional objects in these data memories are known to the skilled person.
In another embodiment, each of the movable rams has a motor, actuator, and/or gear drive.
In this way, it is advantageously possible to convert a single control of a punch into a mechanical movement of the punch. The individual punch can thus either be moved up and down along an axis or, in a further embodiment, be set at an angle.
In a further embodiment, it is provided that a first group of punches is assignable to a first process chamber, a second group of punches is assignable to a second process chamber, and an n-th group of punches is assignable to an n-th process chamber.
Each process chamber can thus be assigned a specific part-building platform (group of punches). A different curable composition, i.e. different material, can be arranged in each process chamber. Thus, a device for simultaneous additive manufacturing of components made of different materials is provided in an advantageous manner.
In a further embodiment, it is provided that the first group of punches with their front sides facing the radiation source and/or radiation deflection device form a first underside of the build platform, the second group of punches with their front sides facing the radiation source and/or radiation deflection device form a second underside of the build platform, and the n-th group of punches with their front sides facing the radiation source and/or radiation deflection device form an n-th underside of the build platform. Thereby, it is preferred if the first group of punches with first underside is reversibly movable into the first process chamber, in particular, the first group of punches can be vertically movable, preferably reversibly, towards the bottom of the first process chamber. Furthermore, it is preferred if the second group of punches with second underside is reversibly movable into the second process chamber, in particular vertically, preferably reversibly, towards the bottom of the second process chamber, and preferably also the n-th group of punches with n-th underside is reversibly movable into the n-th process chamber, in particular vertically towards the bottom of the n-th process chamber, wherein the first, second to n-th process chambers are arranged in the at least one pressure trough. It is further particularly preferred if each group of punches can be controlled individually.
wherein it is further preferred that a first curable composition at the first underside is curable by means of head-over-beam impact and is suitable for bonding the shaped part to be formed from the first curable composition, in particular from the polymerized composition, wherein a second curable composition on the second underside is radiation-curable by means of head-over-head impact and is suitable for bonding the shaped part to be formed from the second curable composition, and wherein an n-th curable composition on the n-th underside is radiation-curable by means of head-over-head impact and is suitable for bonding the shaped part to be formed from the n-th curable composition. Thereby, the bonding of the cured respective first, second or n-th composition to form the respective first, second or n-th shaped part can be performed simultaneously or sequentially.
This allows components of the shaped part to be formed from different compositions to be additively manufactured simultaneously or sequentially in the different process chambers.
According to a further alternative, the build platform with first group of punches, second group of punches to n-th group of punches or a build platform with one punch each, in particular for one process chamber each, can be controlled rotatably or in x,y plane, i.e. horizontally, via the pressure trough in order to control one punch, in particular per process chamber, or a group of first to n-th punches, in particular per process chamber, along the x,y plane. Thus, more than one specific area of a partial build platform (group of punches) are assignable to a process chamber. Alternatively, the pressure trough, and in particular different process chambers, are assignable to specific areas of the part platform along the x,y plane. In this way, moldings of different radiation-curable composition can be built.
The present invention is based on the knowledge that by using a pressure well arrangement containing two or more process chambers under head-over-head impingement with radiation through a transparent pressure bottom plate, arbitrarily composed three-dimensional shaped parts are obtainable generatively. In this process, curable compositions are selectively cured layer-by-layer using generative mask exposure. The respective different shaped parts can be made from at least two different curable compositions. Depending on the choice of curable compositions, these can generate different material properties and/or color impressions in the final product in the cured state. It is thus possible to reproduce the slightest differences in color, making very natural-looking dental products accessible, for example. Color settings can no longer be adjusted by the color setting of one curable composition alone, but by the interaction of two or more curable compositions.
In this context, “face” means the smallest side surface of a cuboid punch which faces the radiation source.
In a further embodiment, the first group of punches is provided with their first front sides in the direction of the radiation source and/or beam deflection device in the moved state on the first underside of the building platform to span a first three-dimensional surface profile, wherein the second group of punches with their second front sides in the direction of the radiation source and/or beam deflection device in the moved state on the second underside of the building platform span a second three-dimensional surface profile, and the n-th group of punches with their third front sides in the direction of the radiation source and/or beam deflection device in the moved state on the third underside of the building platform span a third three-dimensional surface profile.
Different partial profiles of the shaped part to be produced can thus be additively manufactured simultaneously in the different process chambers, with different materials being arranged as the starting substance in the different process chambers. For example, “overhangs” of a shaped part made of different materials can be printed simultaneously.
The three-dimensional surface profile is calculated from the STL or CAD data of the 3D model of the shaped part to be produced and realized by individually controlling and moving the punches from a defined zero position.
In one embodiment, the radiation source is equipped with a projection unit, in particular based on DLP, LCD mask exposure as well as VPP with laser spot exposure.
The preferred radiation source is the LUXBEAM® RAPID SYSTEM (LRS) from Visitech AS. The LUXBEAM® RAPID SYSTEM (LRS) is a DLP®-based stereo lithography subsystem for high-resolution additive manufacturing of parts. The LRS can be configured for, among other things, still image projection typically used in rapid prototyping/manufacturing. The LTR series consists of projectors with different resolutions in combination with a selection of lenses. The LRS supports batch production of many similar parts at high speed. The LRS takes advantage of a moving photo head to create a large build area and enables smart features such as Subpixelation (SPX) to improve resolution and Pixel Power Control (PPC) to provide the same amount of power to each pixel in the resin. The system features an advanced, digitally controlled UV LED radiation source that, combined with robust and reliable DLP® technology, provides a system with long life and low maintenance costs. The LRS is configurable and available in single or multiple head configurations to meet throughput and installation space requirements in the press. Already proven and reliable, the LRS is a plug-and-play system/module. The system is configurable with various high power UV LED options as well as a choice of dedicated UV projection lenses.
It can be provided that the unexposed pixels are defined by a mask stored for the control of the radiation source, in particular a programmable mask, in that certain light points of the radiation source always remain switched off. A mask according to the invention corresponds to a motif of the switched-off light points of the radiation source, wherein the motif is represented in the irradiation field as non-exposed pixels, in particular as a static motif of non-exposed pixels.
By means of the deposited mask, it is achieved in the simplest way that the light intensity is reduced in certain areas of the exposure field. This mask can then be used to achieve homogenization of the exposure field, in particular homogenization of the light intensity of the exposure field, especially preferably homogenization in the temporal integral of the light intensity of the exposure field.
As an alternative to the use of a mask with a background, it is also possible to define the unexposed pixels by blackening the micromirrors or by using an area light modulator with gaps in the lineup of micromirrors or by redirecting the light points through the micromirrors.
In a further embodiment, it is provided that the device for homogenizing the light quantity distribution in the exposure field has an area light modulator which has a plurality of controllable tiltable micromirrors arranged in rows and columns, in which the rays of a two-dimensionally radiating radiation source are imaged via an optical system and an irradiation field of the imaged radiation source is imaged on a projection surface, a number of pixels increasing towards the center of the irradiation field not being exposed, so that in the time integral a homogenization of the light intensity of all pixels exposed on the projection surface is achieved.
The projection surface is preferably formed by the transparent bottom of the pressure trough or, preferably, by the part of the bottom of the respective process chambers used.
Hereby, a particularly well-suited method is provided, with which specific intensity deviations of certain radiation sources, such as beamer types or individual beamers, can also be compensated in a simple manner.
In optics, a projection surface is the surface (often a projection plane) onto which an original image is imaged (projected) by rays.
Area light modulators consist of an array of micromirrors on a semiconductor chip, with the number of mirrors currently varying from several hundred to several million mirrors depending on the application. In most cases, a highly integrated application-specific electronic circuit (ASIC) is used as the basis of the component architecture to enable individual analog deflection of each micromirror. The individual mirrors, which vary in number and size per chip depending on the application, can be individually tilted or lowered to create a two-dimensional pattern that can be used to project defined structures, for example.
In addition, a process for producing at least one three-dimensional shaped part, in particular at least two three-dimensional shaped parts, from at least one separate radiation-curable composition in an apparatus is claimed, in particular for producing at least two three-dimensional shaped parts from at least one separate radiation-curable composition per shaped part, comprising the steps:
Defined layers of the radiation-curable compositions are in particular layers of 5 to 250 micrometers, preferably layers of 20 to 100 micrometers.
In the process according to the invention, at least two to n shaped parts can be produced in two to n process chambers from at least two different radiation-curable compositions.
Therefore, a process for the production of at least two three-dimensional shaped parts from at least one separate composition curable by means of radiation in an apparatus with a pressure trough according to the invention is claimed, which comprises the above-mentioned steps. Here, two shaped parts are produced in one of the process chambers of the pressure trough, while the remaining process chambers are not exposed to radiation. In such a process, the following step thus takes place:
Particularly preferred is a process for the production of at least two three-dimensional shaped parts from at least one separate radiation-curable composition each in an apparatus with a pressure trough according to the invention, comprising the steps mentioned. Here, at least two shaped parts are produced in at least two different process chambers of the pressure trough. Alternatively, two to n shaped parts are producible in two to n process chambers. The two to n shaped parts can also form groups of shaped parts that are printed in groups in two to n process chambers.
Alternatively, at least two to n shaped parts can be produced in the process according to the invention in only one of the two process chambers of the pressure trough according to the invention which are open at the top and have at least two process chambers open at the top. It can be useful to use the pressure trough according to the invention in this constellation as well and to cover the second to n-th process chambers, which may not be used, on the underside in a radiation-impermeable manner, so that radiation-curable compositions present in the second to n-th process chambers can be used later in another printing process. Covering the radiation-curable composition without decanting the composition can have the advantage that less composition is consumed by constant decanting. Therefore, this approach is more economical and minimizes the consumption of composition. According to the invention, the device can be used in a CLIP process and the process can be a CLIP process.
Optionally, processes B) or C) for the production of n-th shaped parts can be carried out in n-th process chambers of the pressure trough that are open at the top and are made of a composition that can be cured by means of n-th jets.
According to an alternative, it may be preferred if, in step c), the moving away from each other takes place in such a way that the first underside of the build platform or a forming part present thereon is no longer in contact, at least in some areas, with the first curable composition in the first process chamber and/or the first bottom of the first process chamber. The aforementioned step c) comprises the steps c) in A) and/or B) each independently.
Likewise, two to n shaped parts can also be built up from different radiation-curable compositions by using the pressure trough according to the invention with at least two process chambers. This is possible by either moving the build platform in x,y-plane above the process chambers correspondingly above other process chambers or moving the pressure trough correspondingly below the build platform correspondingly in x,y-plane.
Thus, the method according to the invention may also comprise c) relatively moving away from each other the second underside and the second bottom of the second process chamber so that the first underside of the build platform or a forming part present thereon is at least regionally no longer in contact with the first curable composition in the first process chamber, in particular until the first underside of the build platform or a forming part present thereon is movable in x,y-plane over the process chambers or the process chambers, i.e. the pressure trough is freely movable in x,y-plane thereunder i.e. the pressure trough is freely movable in x,y-plane below. Assigning the first underside of the building platform or a forming part present thereon to a second process chamber and carrying out C) a) and in particular b) c) and optionally d).
It is preferred if the bottom of the pressure trough has a fluorine-containing polymer coating or a fluorine-containing polymer film as transparent material on the surface facing the at least two process chambers. Preferably, the fluorine-containing polymeric film is replaceable.
Preferably, a pressure trough can be provided, the bottom of which is formed of transparent material. The bottom of the pressure trough preferably comprises at least one or more plates made of borosilicate glass, quartz glass, annealed glass, polymers which are optionally provided with silicone or a film on the surface facing the respective process chambers.
Preferably, in step a), the method in B) may comprise step a2): Moving a first group of punches from a first underside of a build platform to a first position for forming a first three-dimensional surface profile by means of the first end sides of the first group of punches facing the radiation source, wherein initially the first underside faces the bottom of the first process chamber. Analogous procedure can be followed in C) with second and n-th group of punches with second and n-th underside for forming a respective surface profile in second to n-th process chamber.
Furthermore, the invention relates to a process for producing at least one three-dimensional shaped part from at least two different curable compositions, the process comprising the steps of:
In one embodiment, the method comprises the step of: e) removing the shaped part from the first underside of the build platform by moving the punches of the first group to a second position. The same procedure can be used for the second to the n-th shaped part.
In one embodiment, the step sequence a.1) to c) is repeated at least once, preferably n times, before proceeding to step e). The step sequences a.1) to c) and e) can each be carried out independently of one another in A) and/or B). For all statements mentioned in connection with this method, “at least once, preferably n times” may preferably comprise “at least twice to preferably n times”.
In a further embodiment, it is provided that this represents a method for stereolithographically producing at least one three-dimensional shaped part and/or represents such a method for digitally light processing at least one three-dimensional shaped part from at least two curable compositions.
This advantageously provides methods for the simultaneous additive manufacturing of components made of different materials.
The invention also relates to the use of the shaped parts obtained according to the process as a dental shaped part for dental restoration, as a dental prosthesis, as an auxiliary part for a dental prosthesis, as a prosthesis, in particular a bone prosthesis, or a component thereof, or as a hearing aid housing.
The invention further relates to a pressure trough for the device according to the invention. In addition, it is an object of the invention to comprise a kit comprising a pressure trough according to the invention and the device. It may also be useful to associate a pressure trough or a process chamber with a tubular bag having a metering tube with a respective process chamber as a metering system.
The invention further relates to an orthodontic appliance for making a dental splint, using the device according to the invention.
Further details, features and advantages of the invention will be apparent from the drawings, as well as from the following description of preferred embodiments based on the drawings. The drawings merely illustrate exemplary embodiments of the invention, which do not restrict the essential idea of the invention.
A radiation source 4 and/or beam deflector for curing the curable compositions in the process chambers can thus be placed below the pressure well bottom 11 so that head-over-head impingement of the curable compositions 3 with beams can occur. The preferred radiation source is the LUXBEAM® RAPID SYSTEM (LRS) from Visitech AS, which is a DLP®-based stereo lithography subsystem for additive manufacturing.
Irradiation takes place through the pressure trough bottom. Either a large window can be provided across all process chambers 7a, 7b, 7c or an individual irradiation window for each process chamber.
Groups of punches 16a, 16b, 16c of a building platform 9 can be assigned to the individual process chambers 7a, 7b, 7c. The punches 16a, 16b, 16c can be moved out of the plane of the build platform 9 by means of a motor, each individual punch being individually controlled by a microprocessor. The punches 16a, 16b, 16c each form an underside 10a, 10b, 10c facing the radiation source 4 (see
The punch-like platform units advantageously result in an automatic ejection system by selectively retracting or extending the individual punches 16 of the building platform 9 for detaching the printed object/shaped parts 2.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 103 511.2 | Feb 2021 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/053466 | 2/14/2022 | WO |
