3D printer without moving parts

Abstract

A three-dimensional (3D) printer without moving parts, capable of forming the desired 3D object as a whole or in a consecutive series of its sections is disclosed. The said 3D printer comprises a vessel (20) filled with a light curable resin (30) and a holographic projector (40) capable of displaying a computer-generated hologram (10) within the said vessel (20). In one variant, a vessel's heater (21) for adjusting the resin (30) viscosity is applied to achieve the optimum printing conditions. The vessel's walls are transparent for the emitted projector's light spectrum, and the said light spectrum and applied intensity cause a light-curable resin (30) to polymerize in a certain volume and form a solid object (100) within the vessel (20), where mentioned certain volume has the outer contours that match the said computer-generated hologram (10).

Description

[0001] 3D PRINTER WITHOUT MOVING PARTS

[0002] DESCRIPTION

[0003] Technical Field

[0004] The present disclosure relates to the field of 3D printers, more particularly, 3D printers where the object is formed by polymerizing a resin, by applying the UV or near UV source of light on the said resin .

[0005] Technical Problem

[0006] A process known as mask-image-projection-based stereolithography, where a 3D digital model is sliced by a set of horizontal planes is usually associated with the 3D printing technique using resins. Each slice is converted into a two-dimensional mask image. The mask image is then projected onto a photocurable liquid resin surface and light is projected onto the resin to cure it in the shape of the layer, as explained in reference 1) below:

[0007] 1) Zhou, C. , Chen, Y. , Yang, Z. , & Khoshnevis, B. (2013) . Digital material fabrication using mask-image-pro ection-based stereolithography. Rapid Prototyping Journal, 19(3) , 153-165. doi: 10.1108 / 13552541311312148

[0008] Continuous liquid interface production begins with a pool or vessel of liquid photopolymer resin. Part of the pool bottom is transparent to ultraviolet light, which causes the resin to solidify. The object rises slowly enough to allow the resin to flow under and maintain contact with the bottom of the object. Although the above-said method is certainly faster than filament printing via a dot-by-dot approach, it still requires a significant amount of time in printing layer-by-layer and involves a moving mechanism that pulls out the printed obj ect from the resin pool .

[0009] The present invention solves the problem of forming the desired 3D obj ect at once within a pool of liquid photopolymer resin, using the holography principle , more particularly the computer-generated hologram (CGH ) . Such a technique speeds up the whole 3D printing process equally as previously mentioned replacement for the dot-by- dot technique by the layer-by-layer process . As we will see , the only requirement is that the used resin is sensitive to the UV, or near UV light .

[0010] State of the Art

[0011] The state of art is rather crowded with solutions attempting to speed up the 3D printing by using UV, or near UV, curing resins of different kinds and physical properties and various mechanisms helping take out the 3D generated obj ect from the resin or using different devices for forming layer-picture on the top / bottom of the printed obj ect .

[0012] Still , the reference 2 ) below seems to be the inspiration for the present disclosure :

[0013] 2 ) Tomoko Sano , Holography : The Next Disruptive Technology, Weapons and Materials Research Directorate , ARL https : / / apps . dtic . mil / sti / tr / pdf / ADI 033176 . pdf

[0014] Page 6 of reference 2 ) discloses the fog screen developed to produce the 3D image reconstructed using the LCSLM ( Liquid Crystal Spatial Light Modulators ) .

[0015] A good review of available 3D displays , including holographic displays can be found in scientific article 3 ) below : 3) Geng, J. (2013) . Three-dimensional display technologies. Advances in Optics and Photonics, 5 (4) , 456. doi : 10.1364 / aop .5.000456

[0016] However, it should be noted that most of the cited 3D displays in reference 3) are entirely useless for instant 3D printing, or printing in parts, when used with UV-curable resins.

[0017] Summary of the Invention

[0018] In the main embodiment, the present invention reveals a three- dimensional printer without moving parts, capable of forming the desired 3D object. In some variants, the object can be printed in a consecutive series of its sections i = 1, 2 ... N. The disclosed printer comprises : a vessel, optionally equipped with one or more holders extending from the vessel's walls for holding the printed object or desired section of it to the vessel's walls, a light curable resin, filed in the vessel, a holographic projector capable of displaying a computergenerated hologram within the said vessel, and optionally, a vessel's heater for adjusting the resin viscosity.

[0019] The 3D printer vessel's walls and optional holders are transparent for the emitted projector's light spectrum. The said light spectrum and applied light intensity causes a light-curable resin to polymerize and form a solid object, or desired section of it, within the said vessel, and with the contours that match the projected computergenerated hologram into the vessel.

[0020] In a preferred variant, the holographic projector consists of a laser module for generating the light beam with the wavelength capable of curing the resin, and a beam expander for adjusting the beam for the selected active matrix which is controlled from the source outside the said printer. The said active matrix forms a holographic pattern, which is further processed via one or more systems of lenses to form a computer-generated hologram within the said vessel. In the preferred embodiment , the vessel is filled with a light curable resin which does not change its optical properties upon polymerization . In the alternative embodiment , the said vessel is filled with a light curable resin that changes its optical properties upon polymerization . Regardless of the variant , the used light curable resin is a UV or near UV curable resin, preferably those curable with 405 nm. In yet another variant , the heater is present in the vessel and linked with the temperature controller, preferably a PID temperature controller for conditioning the curable resin working temperature .

[0021] Furthermore , the present invention discloses a method for printing a 3D obj ect with the disclosed 3D printer without moving parts . The said method comprises the following steps :

[0022] A. obtaining the pre-processed computer-generated hologram data ( CGHD ) of the original obj ect that should be printed with the method,

[0023] B . correcting the numerical data of CGHD by accounting for the vessel' s refractory index and the used resin' s refractory index ,

[0024] C . preparing the vessel by filling the resin in a quantity to be sufficient for printing the desired 3D obj ect , where , optionally, the transparent holders which will retain the generated 3D obj ect or its section are previously inserted and fixed relatively to the vessel' s walls ,

[0025] D . optionally, adj usting the light curable resin viscosity by the heater and the PID temperature controller ,

[0026] E . proj ecting a computer-generated hologram into the vessel as an entire 3D hologram for the period T sufficient for finishing the polymerization process and producing the 3D obj ect , or, proj ecting a consecutive series of obj ect ' s hologram sections for the period T sufficient for finishing the polymerization process of each section of the said obj ect , where the said method of proj ection depends on the light curable resin used, and the obj ect ' s geometrical properties , F. taking out the newly printed 3D object from the vessel, created by the light-induced polymerization of the said resin, and removing the uncured resin excess and transparent holders, if used, and

[0027] G. optionally, performing additional curing of possibly incompletely cured solid object by applying the curable UV or near UV light on the said object.

[0028] In case hologram sections i=l,...,N, projections are used, the projected sections are selected to begin from the part that is most distant from the holographic projector and to end with the section that is the closest section to the holographic projector.

[0029] In all embodiments, the light intensity and period T are empirically determined to be sufficient for finishing the polymerization process of each section or entire object.

[0030] The present invention reveals the use of the said 3D printer for forming 3D objects from pre-processed computer-generated hologram data (CGHD) .

[0031] Description of Figures

[0032] Figure 1 depicts the essential part of the 3D printer according to the invention, and a method of forming the object as a whole.

[0033] Figure 2 depicts one process for generating the computer-generated hologram data (CGHD) that can be used for the said 3D printer and the corresponding printing process.

[0034] Figure 3 shows the way of forming the physical object's hologram using the CGHD.

[0035] Figure 4 depicts the printing process of an alternative embodiment, where the printing in sections is used to generate the object within the printer's vessel, still with the same printer. Detailed Description of the Invention

[0036] Computer-generated holography

[0037] Computer-generated holography (CGH) is the method of digitally generating holographic interference patterns . A holographic image can be generated, for instance, by digitally computing a holographic interference pattern and printing it onto a mask or film for subsequent illumination by a suitable coherent light source. Alternatively, the holographic image can be brought to life by a holographic 3D display, i.e., a display that operates based on interference of coherent light, bypassing the need of having to fabricate a "hardcopy" of the holographic interference pattern each time. Consequently, in recent times the term "computer-generated holography" is increasingly being used to denote the whole process chain of synthetically preparing holographic light wavefronts suitable for observation by the observer (11) , see reference 4) below:

[0038] 4) Slinger, C., Cameron, C. , & Stanley, M. (2005) . Computer-generated holography as a generic display technology. Computer, 38 (8) , 46- 53. doi : 10.1109 / mc .2005.260

[0039] Computer-generated holograms have the advantage that the objects that one wants to show do not have to possess any physical reality at all, and this is known as synthetic hologram generation. On the other hand, if holographic data of existing objects is generated optically, but digitally recorded and processed, and brought to display subsequently, this is termed CGH as well. Ultimately, computer-generated holography might serve all the roles of current computer-generated imagery: holographic computer displays for a wide range of applications from CAD to gaming, holographic video and TV programs, automotive and communication applications, and many more.

[0040] Figure 2 depicts some processes for forming the CGH. Object (90) can be scanned by any 3D scanner (70) , e.g. , https: / / www.3d-scantech.com / and processed by the computer (80) capable of converting the obtained cloud of points into the set of plains or the CAD 3D model, via appropriate software, usually accompanying the scanner. The object (90) data are further processed in the same or different computer (50) to obtain CGH data (CGHD) , which can be stored or exchanged via cloud storage ( 60 ) .

[0041] The latest state of the art regarding the CGH can be obtained from reference 5) below:

[0042] 5) David Blinder, Tobias Birnbaum, Tomoyoshi Ito, Tomoyoshi Shimobaba . The state-of-the-art in computer-generated holography for 3D displayfJ] . Light: Advanced Manufacturing 3, 35 (2022) . doi: 10.37188 / lam.2022.035

[0043] Holographic projector

[0044] The holographic projectors for projecting the CGH are well-known in the field. For instance, reference 6) discloses the holographic projector using the spatial light modulator arranged to display the hologram, and reference 7) discloses holographic imaging devices, which can realize both a transmission type and a reflection type mode of work.

[0045] 6) EP3679421B1, HOLOGRAPHIC PROJECTOR, filed in the name of Dualitas Ltd., GB

[0046] 7) EP3677969B1, HOLOGRAPHIC IMAGING DEVICE AND DATA PROCESSING METHOD THEREFOR, filed in the name of University Hyogo, JP

[0047] For the present disclosure, the simplest holographic projector (40) is considered the best option, but other techniques can be equally used. It consists of a laser module (41) capable of generating laser light, in our case, the UV or near UV light useful for curing the resin (30) . Such laser can be obtained from: https : / / hubner- photonics . com / product-category / wavelength / 405-nm-laser / . Generated laser light is guided through the beam expander (42) devices that form a collimated beam of light and expand its width to match the active matrix (43) . Most simply, the active matrix (43) can be selected to be an LCD (Liquid Cristal Display) active matrix. The role of the active matrix (43) is to modulate the light beam (49) by an external CGH data pattern (51) , obtained from the external device (50) , i.e., a computer.

[0048] The person skilled in the art will immediately recognize that other types of active matrix can be used to provide the same technical effects, such as LCoS (Liquid crystal on silicon or DMD (Digital Micromirror Device) .

[0049] LCoS is a miniaturized reflective active-matrix liquid-crystal display or "microdisplay" using a liquid crystal layer on top of a silicon backplane. On the other hand, DMD is a semiconductive apparatus wherein addressable and movable radiation-reflecting members comprise a substantial portion of the device, including, by way of illustration, electrostatically controllable, deformable, or deflectable mirrors for forming the patterns. LCoS are well explained in reference 8) and DMDs in reference 9) :

[0050] 8) Guttag, K. M. , Hurley, S., & Mei, B. (2011) . 39.1: Distinguished Paper: Laser+LCOS Technology Revolution. SID Symposium Digest of Technical Papers, 42 (1) , 536-539. doi : 10.1889 / 1.3621379

[0051] 9) Xiong, Z. , Liu, H. , Tan, X., Lu, Z. , Li, C., Song, L., & Wang, Z.

[0052] (2014) . Diffraction analysis of digital micromirror device in maskless photolithography system. Journal of

[0053] Micro / Nanolithography, MEMS, and MOEMS, 13 (4) , 043016. doi : 10.1117 / 1. jmm.13.4.043016

[0054] Finally, the modulated light, whatever process proceeded, is processed through the systems of lenses (44) to obtain the desired hologram (10) in the manner that is common in the art. For observing the hologram, one can use the fog display already mentioned in reference 2) .

[0055] Printer' s vessel

[0056] The essential part of the disclosed 3D printer is the vessel (20) . The said vessel can be of any shape, but the preferred geometry is a prism, as depicted in Fig. 1, essentially for simplifying demanding CGH calculations. Such a vessel has to be made of transparent material for the used UV or near UV light, with the inner volume capable of enclosing the entire object (100) reconstructed from the CGH (10) .

[0057] The printer vessel (20) is, according to disclosure, filled with the 3D printer resin (30) , whose properties are discussed in the next section. The vessel (20) has, optionally, a mechanical means for attaching one or more transparent holders (22) to the said vessel's wall. By the term "transparent" we mean transparent for the used UV or near UV light spectrum. The said transparent holders (22) are preferably made as tiny transparent wires or rods, enabling the cured object (100; 100. i) to be additionally fixed to the said vessel's wall .

[0058] The printer vessel (20) can be equipped with the heater (21) in order to set and maintain the resin (30) temperature at the optimum. Said heater (21) is controlled by the corresponding temperature controller, preferably the standard PID temperature controller known in the art, see for instance reference 10) :

[0059] 10 ) https : / / www . ni . com / en / shop / labview / pid- theory-explained . html

[0060] Furthermore, the heating process can be programmed in a manner to firstly heat up to resin (30) to change the viscosity and to facilitate eventually trapped air-bubbles removing process from the resin (30) , and then to stabilize the resin' s temperature to optimum. Finally, it is worth noting that there are no moving parts within the said vessel (20) .

[0061] 3D printer' s resin

[0062] The curing of 3D printer resin is the process of exposing the liquid solution to UV, or near UV light, to activate the chemical reaction that solidifies it via polymerization.

[0063] In the case of the disclosed 3D printer without moving parts, it is essential that the used resin is sensitive to the applied UV or near UV spectrum. Resin is generally cured by a certain UV or near UV spectrum, but not under any intensity of light. For the resin to truly harden, it is necessary for the volume element of the resin to absorb a certain, well-defined, amount of energy from the UV source. Since physically the intensity of the laser is higher in the volume area of the reconstructed hologram, then it is possible to optimize the energy of the laser beam to a level that will not result in the hardening of the resin in the entire area where the laser penetrates through the vessel with the resin, but only where the desired hologram is created / recons true ted .

[0064] This laser beam (49) can penetrate the resin (30) similar to how it penetrates through the fog chamber disclosed in reference 2) . For the selection of such resins, it is possible to use one from reference 11) below:

[0065] 11) The Best Resins for 3D Printers in 2023 - Buyer's Guide, by Leo Greguric and Ross Lawless, from: https : / / all 3 dp . com / 2 / best-resin-f or-3d-pr inter / and pick Henkel's Loctite 3843 HDT60 clear resin. Other similar resins can be equally used. It should be worth noting that two-photon polymerization is a nonlinear optical process based on the simultaneous absorption of two photons in photosensitive material. This process changes the photosensitive material, i.e. , it leads to polymerization by activating so-called photo-initiators in the resin. The principles of this technique are explained in reference 12) below:

[0066] 12) O'Halloran, S. , Pandit, A. , Heise, A. , Kellett, A., Two-Photon Polymerization: Fundamentals, Materials, and Chemical

[0067] Modification Strategies. Adv. Sci . 2023, 10, 2204072 https: / / doi.org / 10.1002 / advs .202204072

[0068] Effectively, it means that the resin sensitive to 405 nm can be activated with 810 nm as well, using higher light intensities to provide the same polymerization rates.

[0069] 3D printer and its working principle

[0070] The three-dimensional printer without moving parts is disclosed. It is designed to form the desired 3D object (100) as a whole or by forming the object in a consecutive series of its sections (100. i) , i = 1, 2 ... N from projected CGH (10) or CGH parts (10. i) .

[0071] To be operative, the said printer comprises: a vessel (20) , optionally equipped with one or more holders (22) extending from its walls for holding the printed object (100) or desired section (100. i) of it to the vessel's walls, a light curable resin (30) , filed in the vessel (20) , a holographic projector (40) capable of displaying a computergenerated hologram (10) within the said vessel (20) , and optionally, a vessel's heater (21) for adjusting the resin (30) viscosity, as explained before.

[0072] The vessel's walls and optional holders (22) are transparent for the emitted projector's light spectrum. The said light spectrum, i.e., the wavelength, and applied light intensity causes a light-curable resin (30) to polymerize and form a solid object (100) , or desired section (100. i) of it.

[0073] The printing method

[0074] A method for printing a 3D object (90) with the 3D printer without moving parts comprises the following steps A-G, described below.

[0075] Step A:

[0076] It is assumed that the computer-generated hologram data (CGHD) of the desired object (90) is obtained from the computer (50) or downloaded from the cloud storage (60) . The CGHD is the uncorrected row hologram data .

[0077] Step B:

[0078] It is necessary to correct the numerical data of CGHD by accounting for the vessel' s refractory index and the used resin' s refractory index as well as the lens aberration and the taken geometry, see references below:

[0079] 13) ZHANG, H. et al. Error correction of a phase-only computergenerated hologram for an aspheric surface. Journal of the European Optical Society - Rapid publications, Europe, v. 9, sep. 2014. ISSN 1990-2573. DOI : 10.2971 / j eos .2014.14039

[0080] 14) Antun Lovro Brkic, Vladimir Cviljusac, Hrvoje Skenderovic, and

[0081] Mario Rakic, "Unifying fast computer-generated hologram calculation and prepress for new and existing production techniques," Appl . Opt. 62, D119-D124 (2023) . https: / / doi.org / 10.1364 / AO .478388 After this step, the CGH is ready to be used for the printing process. In the case of sectional printing, the CGH (10) is divided into N CGHs (10. i) , i = 1,...,N.

[0082] Step C:

[0083] Now, the vessel (20) is filled with resin (30) in a quantity to be sufficient for printing the desired 3D object (100) . If the transparent holders (20) are used, they are already positioned and attached to the vessel's walls to hold the generated / solidif ied 3D object (100) or one or more of its sections (100. i) , i=l ... N. The filling process has to be slow to minimize the number of undesired air bubbles .

[0084] Step D:

[0085] This step is optional and is used mainly to adjust the light curable resin (30) viscosity by the heater (21) and the corresponding PID temperature controller.

[0086] Step E-l:

[0087] In this step, projecting a whole computer-generated hologram (10) is performed into the vessel (20) . So, an entire 3D hologram (10) is projected for the period T which is sufficient for finishing the polymerization process and producing the 3D object (100) at once. This method works well for small objects and when the cured resin (30) retains its refractive index during the curing process.

[0088] Step E-2:

[0089] Instead of step E-l, alternatively, step E-2 is employed. From step B is extracted the CGH (10) which is divided into N CGHs (10. i) , i = 1, ...,N. Then, a consecutive series of object's (90) hologram sections (10. i) , i=l,...,N is projected for the period T sufficient for finishing the polymerization process of each section (100. i) of the object (100) within the said vessel (20) . This process is depicted in Fig. 4. In this alternative step, the projected sections are selected to begin from the part that is most distant from the holographic projector (40) , and end with the section that is the closest section to the holographic projector (40) , having in mind beam (49) direction. In addition, the time period used to reconstruct the sections is empirically determined, i.e., At± for curing the desired slice (100. i) . In practice, one At is a common selection for the same slice's thickness .

[0090] The method described in this step E-2 is useful if the light curable resin (30) changes its properties, i.e. , transparency and / or refractory index once cured, or the object's (90) geometrical properties do not allow the whole object's curvature to be restored. Other options of 3D printing in sections / parts are also possible and trivial for the person skilled in the art.

[0091] Step F:

[0092] Step F is oriented toward taking out the newly printed 3D object (100) from the vessel (20) , created by the light-induced polymerization of the said resin (30) . It consists of removing the uncured resin (30) excess and transparent holders (22) , if used. The person skilled in the art will recognize that the transparent holders will remain partially trapped in the printed object (100) .

[0093] Step G:

[0094] Optionally, in Step G additional curing of possibly incompletely cured solid object (100) by applying the curable UV or near UV light on the said object (100) is performed. It is known in the art, see reference 15)

[0095] 15) Martina Staffova, Frantisek Ondreas, Juraj Svatik, Marek Zboncak,

[0096] Josef Jancar, Petr Lepcio, 3D printing and post-curing optimization of photopolymerized structures: Basic concepts and effective tools for improved thermomechanical properties, Polymer Testing, Volume 108, 2022, 107499, ISSN 0142-9418. https: / / doi.Org / 10.1016 / j . polymer testing .2022.107499

[0097] This post-print curing is a required step of many resin printing, just like support removal and bed leveling. If skipped, the final product will be a soft, weak, and undesirable print. To get the most out of any high-resolution resin printer, the common practice is to perform post-print curing.

[0098] Industrial Applicability

[0099] A three-dimensional (3D) printer without moving parts, capable of forming the desired 3D object as a whole or in a consecutive series of its sections is disclosed. The industrial applicability of such a class of inventions is obvious.

[0100] Reference numbers

[0101] 10 Object's Hologram, i.e. , Computer Generated Hologram (CGH) ,

[0102] 11 Observer' s points

[0103] 20 Transparent vessel

[0104] 21 Heater

[0105] 22 Transparent holder

[0106] 30 Light curable resin,

[0107] 40 Holographic projector

[0108] 41 Laser module

[0109] 42 Beam expander

[0110] 43 Active matrix

[0111] 44 Systems of lenses

[0112] 49 Beam

[0113] 50 Computer, capable of generating CGH,

[0114] 51 CGH data pattern

[0115] 60 Cloud storage

[0116] 70 3D scanner

[0117] 80 Computer, capable of converting cloud of points into the plane (s) , and / or generating CAD 3D model,

[0118] 90 Original object

[0119] 100 Reconstructed object

Claims

CLAIMS1. A three-dimensional printer without moving parts, capable of forming the desired 3D object (100) as a whole or by forming the object in a consecutive series of its sections (100. i) , i = 1, 2 ... N, where the said printer comprises: a vessel (20) , optionally equipped with one or more holders (22) extending from its walls for holding the printed object (100) or desired section (100. i) of it to the vessel's walls, a light curable resin (30) , filed in the vessel (20) , a holographic projector (40) capable of displaying a computer-generated hologram (10) within the said vessel (20) , and optionally, a vessel's heater (21) for adjusting the resin (30) viscosity, wherein the vessel's walls and optional holders (22) are transparent for the emitted projector's light spectrum, and where the said light spectrum and applied light intensity causes a light curable resin (30) to polymerize and form a solid object (100) , or desired section (100. i) of it, within the said vessel (20) with the contours that match the projected computer-generated hologram (10) into the vessel (20) .

2. The three-dimensional printer without moving parts according to claim 1, where the holographic projector (40) consists of a laser module (41) for generating the light beam (49) with the wavelength capable of curing the resin (30) , a beam expander (42) for adjusting the beam for the selected active matrix (43) , controlled from the source outside the said printer, where the said active matrix forms a holographic pattern, which is further processed via one or more system of lenses (44) to form a computer-generated hologram (10) within the said vessel (20) .

3. The three-dimensional printer without moving parts according to any of the claims 1-2, where the said vessel (20) is filled witha light curable resin (30) which does not change its optical properties upon polymerization.

4. The three-dimensional printer without moving parts according to any of the claims 1-2, where the said vessel (20) is filled with a light curable resin (30) which changes its optical properties upon polymerization.

5. The three-dimensional printer without moving parts according to any of the preceding claims, where the used light curable resin (30) is a UV or near UV curable resin, preferably those curable with 405 nm.

6. The three-dimensional printer without moving parts according to any of the preceding claims, where the heater (21) is present and linked with the temperature controller, preferably a PID temperature controller for conditioning the curable resin (30) working temperature.

7. A method for printing a 3D object (90) with the 3D printer without moving parts, according to any of the claims 1-6, where the said method comprises the following steps:A. obtaining the pre-processed computer-generated hologram data (CGHD) of the original object (90) that should be printed with the method,B. correcting the numerical data of CGHD by accounting for the vessel' s refractory index and the used resin' s refractory index,C. preparing the vessel (20) by filling the resin (30) in a quantity to be sufficient for printing the desired 3D object (100) , where, optionally, the transparent holders (20) which will retain the generated 3D object (100) or its sections (100. i) are previously inserted and fixed relatively to the vessel's walls,D. optionally, adjusting the light curable resin (30) viscosity by the heater (21) and the PID temperature controller,E. projecting a computer-generated hologram (10) into the vessel (20) as an entire 3D hologram (10) for the period T sufficient for finishing the polymerization process and producing the 3D object (100) , or, projecting a consecutive series of objects (90) hologram sections (10. i) , i=l,..., N for the period T sufficient for finishing the polymerization process of each section (100. i) of the object (100) , where the said method of projection depends on the light curable resin (30) used, and the object (90) geometrical properties,F. taking out the newly printed 3D object (100) from the vessel (20) , created by the light-induced polymerization of the said resin (30) , and removing the uncured resin (30) excess and transparent holders (22) , if used, andG. optionally, performing additional curing of possibly incompletely cured solid object (100) by applying the curable UV or near UV light on the said object (100) .

8. The process for printing a 3D object (90) with the 3D printer without moving parts according to claim 7, where when hologram sections (10. i) , i=l,..., N, projections are used, the projected sections are selected to begin from the part which is most distant from the holographic projector (40) and to end with the section that is the closest section to the holographic projector (40) .

9. The process for printing a 3D object (90) with the 3D printer without moving parts according to claim 7 or 8, where the light intensity and period T are empirically determined to be sufficient for finishing the polymerization process of each section (100. i) or entire object (100) .

10. Use of the process according to any of the claims 7-9, for forming 3D objects from the pre-processed computer-generated hologram data .

Images