KR20230065320A - Systems for obtaining photopolymerized prepolymers - Google Patents

Abstract

Photopolymerized prepolymer manufacturing systems can create materials suitable for 3D printing buildings or building components. The system may include a conveyor, a prepolymerization chamber, and one or more processors. The prepolymerization chamber may have a plurality of prepolymerization stations arranged sequentially, and as the conveyor moves the prepolymer past the prepolymerization chamber, it may convert untreated material to lightcured prepolymer material. The processor(s) may control the operation of the conveyor, prepolymerization chamber, or both to change operation in response to detected system events. Each polymerization station may include a light source such as an LED array that illuminates the material. Each light source may be on a lid of a prepolymerization station. If one polymerization station is out of operation, such as for maintenance, the system may increase the light intensity of the remaining polymerization stations, slow the conveyor, or both.

Description

Systems for obtaining photopolymerized prepolymers

(Cross Reference to Related Applications)

This application claims the benefit of U.S. Patent Application Serial No. 16/397,655, filed on April 29, 2019, entitled "SYSTEM FOR OBTAINING A PHOTOPOLYMERIZED PREPOLYMER", which is hereby incorporated by reference in its entirety. included in

The present disclosure relates generally to prepolymers, and more specifically to the production of photopolymerized prepolymers suitable for use as building materials.

Over the past decade, three-dimensional ("3D") printing has become a buzzword in the industry and is beginning to penetrate this sector as well as the architectural sector. Now, with 3D printers capable of printing building walls and handling cement, the technology could help reimagine traditional building techniques and products. The history of 3D printing in architecture is not yet rich. In 2004, the University of South Carolina attempted to fabricate a wall by 3D printing, which was widely accepted as the technology's first introduction to construction. In 2014, a complete canal house built using 3D printing was completed in Amsterdam. In 2016, a 3D printed mansion was completed in China. Also in 2016, Dubai Future Foundation built offices via 3D printing, which is considered a major milestone for technology in the commercial construction sector. The fully functioning 2,700-square-foot building was built in just 17 days on a large 3D printer measuring 120 by 40 by 20 feet.

The benefits of 3D printing in construction are speed, reduced waste, design freedom, and reduced human error. The challenges of 3D printing in construction are high cost, lack of labor, quality control, and lack of proper regulations. Nevertheless, the use of 3D printing in construction has already been mentioned in the patent literature, which includes polymerization systems that cure a starting photopolymerizable material by photopolymerization.

Accordingly, U.S. Patent No. 9,394,441 issued July 19, 2016 to P. Xu et al. discloses a building material for use in a three-dimensional printing system. The material consists of a curable oligomeric material, a reactive component, a non-reactive component including one or more urethane waxes, and one or more diluents. The reactive component of the material is at least one chemical moiety polymerizable with a chemical moiety contained in the oligomeric curable material and/or at least one diluent. Reactive components are present in building materials as crystalline regions.

Although U.S. Patent No. 9,394,441 does not explicitly teach curing of polymeric materials by photopolymerization, it can be assumed that such a curing method is provided. In some embodiments, suitable photoinitiators are acetophenones, suitably 2,2-dialkoxybenzophenones and 1-hydroxyphenylketones such as 1-hydroxycyclohexylphenylketone or 2-hydroxyisopropylphenyl It is mentioned to include those operable for use with the HeCd laser radiation source, including ketones (=2-hydroxy-2,2-dimethylacetophenone).

Additionally, in some embodiments, suitable photoinitiators include those operable for use with Ar laser radiation sources that include benzylketals, such as benzyldimethylketals. In some embodiments, the photoinitiator comprises α-hydroxyphenylketone, benzyldimethylketal or 2,4,6-trimethylbenzoyldiphenylphosphineoxide or mixtures thereof.

US Patent No. 6,927,018 issued to R. Burgess on August 9, 2005 relates to three-dimensional printing using photoactivated building materials. This disclosure discloses methods, articles of manufacture, and systems for manufacturing articles using photoactivatable building materials. The method comprises applying a layer of the photoactivatable building material to a preselected surface, using a plurality of light emitting centers to photoactivate the layer of the photoactivatable building material according to a predetermined light initiation process to obtain polymerization of the building material. scanning, wherein the scanning is performed at a predetermined distance using a predetermined light intensity, repeating the step of applying the layer, each layer being applied to the immediately preceding layer, and until the article is manufactured. scanning the layer having a plurality of light emitting centers to polymerize the building material. A photoactivatable building material exemplified herein as a suitable material for fabrication of building components in the proposed 3D printing method is Shipley Microposit SI 800 series photoresist. Shipley Microposit S1800 series photoresists are optimized for G-ray (0.436 micron) exposure, effective for broadband exposure, and have high-resolution process parameters. For example, Shipley Microposit S1813 is 12.3 microns thick, requires 150 mJ/cm for polymerization ("printing"), and can be cured in G-line (0.54 NA).

However, while previous methods of forming organic polymers have worked well in the past, improvements are always useful. In particular, improved systems and methods for forming photopolymerized prepolymers suitable for use in 3D printing of architectural components are desired. .

The present disclosure relates to systems and methods for obtaining photopolymerized prepolymers as materials suitable for manufacturing buildings or building components using 3D printing processes. These building components may include walls, floors, exterior and interior cladding, furniture, other outdoor and indoor features, and the like. This is done using a system that includes a closed-loop conveyor, such as a flexible belt, stretched between a precursor loading station and a prepolymer material receiver where the product is unloaded into a mixer where inorganic fillers are added and then sent to an architectural 3D printing machine. can be achieved The conveyor may carry a plurality of flexible trays that loop around the pulleys of the closed loop conveyor. One pulley may be a driving pulley having a driving motor. The tray is a shallow trough open at the top and carrying the dosed portion of the precursor, which is light-cured en route from the loading station to the unloading station by passing sequentially under the light sources of the two light-curing stations .

The conveyor may have a loading station for raw (ie precursor) material and an unloading location on the opposite side of the loading station. The trays can receive material that is directed upward, passed through an unloading station, and then directed downwards and returned to a loading station on the underside of the conveyor. The photopolymerization station may include a plurality of light emitting devices operating at a predetermined wavelength(s) and irradiating the material in the tray with a predetermined dosed amount of light energy to pre-cure the material to a desired viscosity. Parameters of the process, such as viscosity, radiation dose, exposure time, exposure intensity, temperature, etc., can be automatically controlled by the central processing unit. Prior to unloading, the uncured liquid may be separated from the pre-cured prepolymer and returned to the loading station for reuse.

In various embodiments of the present disclosure, a photopolymerized prepolymer manufacturing system can include at least a conveyor, a prepolymerization chamber, and one or more processors. The conveyor may be configured to move the raw material from the loading area to the unloading area. The prepolymerization chamber may be located proximate to the conveyor and may have a number of prepolymerization stations arranged sequentially relative to the conveyor. As the conveyor moves the raw material past the prepolymerization chamber, it may convert at least a portion of the raw material into a photopolymerized prepolymer material. The processor(s) may be configured to control operation of the conveyor, prepolymerization chamber, or both, and may change operation of the conveyor, prepolymerization chamber, or both in response to detected system events.

In various detailed embodiments, the photopolymerized prepolymer material (after adding the inorganic filler) may be suitable for use in 3D printing of buildings or building components. Each of the plurality of prepolymerization stations may include one or more light sources that illuminate the raw material as the conveyor moves it past the prepolymerization chamber. Each of the plurality of prepolymerization stations further includes a lid facilitating access to one or more light sources, and the light sources may be contained within the lid. Some or all of the light source may include an array of light emitting diodes (“LEDs”). In various embodiments, the detected system event may include interrupted operation of one of the plurality of prepolymerization stations. The processor(s) may be configured to increase the intensity of one or more light sources at the remaining prepolymerization stations in response to interrupted operation of one of the plurality of prepolymerization stations. Each of the plurality of prepolymerization stations may also include at least one fan and one or more vents to facilitate air circulation as the conveyor moves the raw material past the prepolymerization chamber.

In various further embodiments of the present disclosure, a prepolymerization chamber configured to convert a material to a photopolymerized prepolymer material may include a first prepolymerization station and a second prepolymerization station. The first prepolymerization station can include a first light source configured to irradiate the material at a first intensity level as the separate conveyor moves the prepolymer material past the first prepolymerization chamber, the second prepolymerization station comprising: A separate conveyor may include a second light source configured to illuminate the material at a second intensity level as it moves past the second prepolymerization chamber. The prepolymerization chamber may be configured to automatically increase the first intensity level when the second prepolymerization station ceases operation, and also automatically increase the second intensity level when the first prepolymerization station ceases operation. can be configured to do so.

In various detailed embodiments, the prepolymerization chamber also includes a first lid of the first prepolymerization station that facilitates access to the first light source and a second lid of the second prepolymerization station that facilitates access to the second light source. lead may be included. A first light source can be included in the first lead, a second light source can be included in the second lead, and both light sources can include an array of LEDs. The prepolymerization chamber is also configured to automatically increase the first intensity level when the second prepolymerization station ceases operation, and to automatically increase the second intensity level when the first prepolymerization station ceases operation. can include The processor may also be configured to interface with a separate processor controlling the separate conveyor, which may be configured to interface with a separate conveyor to slow down the separate conveyor when the first prepolymerization station is out of operation or when the second prepolymerization station is out of operation. This may include providing instructions to the processor. Suspended operation of one of the first or second prepolymerization stations while the other prepolymerization station continues to operate may include performing maintenance on the suspended prepolymerization station. . The prepolymerization chamber may also include a first fan of the first prepolymerization station, a second fan of the second prepolymerization station, and a plurality of vents of the first and second prepolymerization stations. Fans and vents can facilitate air circulation as separate conveyors move the material past the prepolymerization chamber.

In still further embodiments of the present disclosure, various methods of obtaining photopolymerized prepolymer materials are provided. Suitable method steps include introducing uncured liquid material onto a conveyor at a loading location, moving the conveyor until the material is located in the first prepolymerization station of the entire prepolymerization chamber, and moving the material to the first prepolymerization station. exposing the material to a first dose of radiation in the chamber, moving the conveyor until the material is located in the second pre-polymerization station of the entire pre-polymerization chamber, and moving the material to the second pre-polymerization station. It may include exposing to a second dose of radiation at . The second dose of radiation can cure at least a portion of the material into a photopolymerized prepolymer material. Additional method steps include separating the cured portion of the photopolymerized prepolymer material from the remaining uncured liquid material, returning the remaining uncured liquid material to the loading position of the conveyor, It may include feeding the portion through a shredder, and delivering the pulverized photopolymerized prepolymer to a receiving portion.

Other devices, methods, features and advantages of the present disclosure are or will become apparent to those skilled in the art upon review of the following figures and detailed description. All such additional devices, methods, features and advantages are intended to be included within this specification, within the scope of this disclosure, and protected by the appended claims.

The included drawings are for illustrative purposes and serve only to provide examples of possible structures and arrangements for the disclosed features, devices, systems and methods for obtaining photopolymerized prepolymers. These drawings do not limit any changes in form and detail that may be made to this disclosure by one of ordinary skill in the art without departing from it and its scope.
1 shows a schematic diagram of an exemplary system for obtaining a photopolymerized prepolymer according to one embodiment of the present disclosure in a side view.
FIG. 2 illustrates an exemplary tray for use on a conveyor of the system of FIG. 1 in a front perspective view according to one embodiment of the present disclosure.
FIG. 3 shows a front perspective view of an exemplary conveyor and prepolymerization chamber for use with the system of FIG. 1 according to one embodiment of the present disclosure.
4 shows a top view of the conveyor and prepolymerization chamber of FIG. 3 according to one embodiment of the present disclosure.
FIG. 5 shows the conveyor and prepolymerization chamber of FIG. 3 in a cross-sectional rear view according to one embodiment of the present disclosure.
6A illustrates the conveyor and prepolymerization chamber of FIG. 3 in cross-sectional side view according to one embodiment of the present disclosure.
FIG. 6B illustrates a side view of the conveyor and prepolymerization chamber of FIG. 3 according to one embodiment of the present disclosure.
FIG. 7 shows the conveyor and prepolymerization chamber of FIG. 3 in a rear perspective view with one prepolymerization station lid open, according to one embodiment of the present disclosure.
8A shows an exemplary prepolymerization chamber in front view according to one embodiment of the present disclosure.
FIG. 8B illustrates a bottom plan view of the prepolymerization chamber of FIG. 8A according to one embodiment of the present disclosure.
9 depicts a flow diagram of an exemplary method of obtaining a photopolymerized prepolymer material according to one embodiment of the present disclosure.

Example applications of devices, systems, and methods according to the present disclosure are described in this section. These examples are provided only to add context and aid in the understanding of the present disclosure. Accordingly, it will be apparent to those skilled in the art that the present disclosure may be practiced without some or all of these specific details being provided herein. In some instances, well known process steps have not been described in detail to avoid unnecessarily obscuring the present disclosure. As other applications are possible, the following examples should not be considered limiting. In the detailed description that follows, reference is made to the accompanying drawings, which form a part of the description, in which specific embodiments of the present disclosure are shown by way of example. Although these embodiments have been described in sufficient detail to enable one skilled in the art to practice the present disclosure, these examples are non-limiting, so that other embodiments may be used and changes may be made without departing from the spirit and scope of the present disclosure. understand

The present disclosure, in various embodiments, relates to features, devices, systems, and methods for obtaining photopolymerized prepolymers. In particular, the disclosed embodiments provide photopolymerized prepolymers (including inorganic fillers) suitable for use as 3D printing materials in the 3D printing of buildings and building components such as walls, floors, exterior and interior cladding, furniture, other outdoor and indoor features, and the like. after addition) can be used to obtain The disclosed system may include a conveyor, a prepolymerization chamber, and one or more processors for this purpose.

The prepolymerization chamber may have a plurality of prepolymerization stations arranged sequentially to convert untreated material to photopolymerized prepolymer material as the conveyor moves the prepolymer past the prepolymerization chamber. Each polymerization station may include a light source that illuminates the material, and each light source may be within the lid of the prepolymerization station. If one polymerization station is out of operation, the system processor(s) may increase the light intensity of the remaining polymerization stations, slow the conveyor, or both.

While the various embodiments disclosed herein discuss specific formulations of materials, and specific light devices for curing the materials, the disclosed features, devices, systems, and methods can be applied to other formulations of materials, and 3D applications of buildings and building components. It will be readily appreciated that other curing devices may similarly be used to cure materials suitable for printing. For example, the disclosed features and embodiments may be used with other types of light of different wavelengths, and other arrangements of prepolymerization stations, such as one, three, or more stations, may be used. Other applications, devices, and extrapolations beyond the illustrated embodiments are also contemplated.

full system

Referring first to FIG. 1 , a schematic diagram of an exemplary system ("System") for obtaining a photopolymerized prepolymer is shown in a side view. System 20 is for the production of photopolymerized organic materials for use in combination with other components in the manufacture of buildings or building components by 3D printing. System 20 continuously and effectively prepolymerizes a photocurable and photopolymerizable material by irradiating the prepolymerizable material under the influence of light emitted from an installed light source while the photopolymerizable material is being conveyed from the starting material loader to the prepolymerized material discharging station. is to provide

More specifically, as shown in FIG. 1 , system 20 is a closed loop conveyor 22 , for example, from a loading location, i.e., a prepolymeric material input station 24, to an unloading location on the opposite side of the loading location. , ie a conveying unit in the form of a flexible belt extending to the prepolymerized material discharge station 26 . The input station is provided with a tank 27 containing a starting light-prepolymerizable material 28 in liquid state and solid PEG 4000 powder (in some formulations) suspended in a liquid medium.

A closed loop conveyor 22, i.e., a flexible belt, is guided around pulleys 30 and 32, one of which, for example pulley 30, is a drive pulley and the other, pulley 32, is a driven pulley. . The pulley 30 is rotationally driven by a motor 34 through a driver (not shown). The upper run of conveyor 22 moves in the direction of arrow A (FIG. 1). A plurality of prepolymerization trays (hereinafter referred to as "material receiving trays") 36a, 36b, ... 36n are attached to the surface of the conveyor 22 (FIG. 1). The trays may be spaced from each other at a predetermined distance or may be connected to each other as links of a tractor track.

Continuing with FIG. 2 , an exemplary tray for use on a conveyor of the system of FIG. 1 is shown in a front perspective view. The tray 36a may be a shallow rectangular trough having an open top, side walls 36a1 , 36a2 , 36a3 , and 36a4 and a bottom plate 38 . It should be understood that the material receiving tray is shown as a rectangular body by way of example only, and that the tray may be square, hexagonal, or any other suitable shape. Since the trays 36a, 36b, ... 36n are secured to the conveyor 22, i.e. the belt, and must pass around the pulleys 34 and 36, they are chemically inert to the liquid photopolymerizable material 28 and around the pulleys. made of a flexible material, such as silicon, that can be cycled into In order to enhance the curing efficiency of the photopolymerizable material, the inner surfaces of the side walls 36a1, 36a2, 36a3, and 36a4 and the bottom plate 38 may be coated with a reflective coating.

That is, the conveyor 22 has a loading position on the side of the raw material loading station and an unloading position on the opposite side of the loading position, wherein when the material receiving tray passes through the unloading position, the material receiving tray is in an inverted position, i.e. The open top of the tray is switched to a downward position.

The system 20 is located on top of a conveyor 22 for passing material receiving trays 36a, 36b, ... 36n en route from the loading material input station 24 to the prepolymerized material discharge station 26. and a stationary prepolymerization chamber 38 which may have a first prepolymerization station 38a and a second prepolymerization station 38b arranged sequentially. The material receiving trays 36a, 36b, ... 36n, inter alia, are controlled by the central processing unit 40, which controls the operating speed of the drive motor 34 of the drive pulley 30 via the feedback line 42. It passes through the prepolymerization stations 38a and 38b either continuously or intermittently.

Two prepolymerization stations 38a and 38b may be used rather than just one so as not to disrupt the process. If one of the stations fails, the other station continues to operate and the process is not interrupted. In various embodiments, dividing the light-prepolymerization process into two or more stages allows more precise selection of the viscosity of the final product, since the light-prepolymerization kinetic curve can have an exponential shape. During normal operation of the two stations, the light energy dose can be shared 50%/50%. If only one station is operating, the load on it increases.

In addition, the use of a two-stage prepolymerization makes it possible to better control the prepolymerization process and improve the quality of the obtained product. Additional capabilities and features of the prepolymerization chamber 38 and its various components are provided in more detail below in FIGS. 3-8B and their associated descriptions.

The photopolymerizable material filling the material receiving trays 36a, 36b, ... 36n is supplied to these trays from the input station tank 37 via a dosing valve 44. The materials contained in the trays are preliminarily prepared by photopolymerization under the influence of light emitted from light sources 46 and 48 installed in respective stations 38a and 38b directly on the path of the material receiving trays 36a, 36b, ... 36n. polymerizes Each light source 46 and 48 may include, for example, multiple LEDs.

The light sources 46 and 48 of the two stations 38a and 38b may provide total light illumination power in the range of 2 to 50 Wt, for example. According to one specific embodiment of the present invention, at each station, the LEDs are arranged in a flat matrix in a rectangular or square configuration. LEDs can run in a variety of lengths, such as 405nm, 440nm, etc. The primary requirement for light sources 46 and 48 is to provide high uniformity of illumination of the material in the tray with an accuracy within ±5%. Each light source 46 and 48 may include, for example, 300 LEDs. It is understood that this amount is given as an example only, and that the final result will be defined by the total dose with which the prepolymerizable material is irradiated. Light sources 46 and 48 are interchangeable and can operate at the same or different wavelengths.

It is known that different photopolymerizable precursors may react differently to irradiation with different wavelengths of light. Thus, as described above, the light sources 46 and 48 are interchangeable and may be composed of LEDs of different wavelengths. For example, light sources 46 and 48 can operate on a wavelength of 405 nm or 440 nm, or one of them can operate on a wavelength of 405 nm and the other can operate on a wavelength of 440 nm. It is understood that specific wavelengths are given by way of example only.

An optimal dose to obtain a final product with optimal parameters acceptable for the subsequent use of the resulting prepolymer for mixing with other components used in 3D printing can be achieved by adjusting the exposure time and illuminator power. That is, the dose amount (D) can be expressed by the following formula: D = W t _exp (where W is the power to which the prepolymerizable material is exposed, and t _exp is the exposure time). Thus, the value of D can be adjusted by changing the power W, the exposure time t _exp , or both.

The curing time for which the photopolymerizable material stays under the light emitter and the intensity of the light power emitted, i.e. the radiation dose, can be adjusted (eg within a range of 2 seconds to 60 seconds), and the materials used and the prepolymerized materials to be accommodated depends on the viscosity of

The prepolymerized material obtained after passing through the second exposure station 38b (after homogenization) is a gelatinous material having a viscosity in the range of 10,000 to 100,000 cPs. In practice, the material obtained at this stage consists of a gelatinous substance and a liquid. The viscosity is selected to provide flowability of the 3D printing material produced by mixing with the resulting prepolymer through the pipeline of a 3D printing machine (not shown).

The prepolymerized material discharge station 26 includes a separator 50 into which the prepolymerized product that has passed through the second station 38b falls from the tray into the separator as it is circulated over the driven pulley 32. The interior of the separator is divided by a tiltable sieve 50c into two sections 50a and 50b, such that the liquid phase of the prepolymerized material passes into section 50b and retains the gelatinous phase in section 50a. From section 50a, the gelatinous phase is fed through funnel 51 to the prepolymerized material receiving portion. Where shown, the prepolymerized material receiving portion is shown as a crusher such as crusher 52 . The shredder 52 may be a conventional industrial shredder such as Twin Shaft Wagner Shredder WTS500 (Austria). The mill breaks the gelatinous material into small pieces having dimensions in the range of, for example, 1-10 mm.

The final pulverized prepolymerized product, which is one of the components to be mixed with minerals or other materials required for 3D printing of buildings or building components, is transferred from the final prepolymer receiver 54 to a 3D printing machine (not shown) in the system. (after adding mineral filler (not shown)). At the same time, the liquid phase of the prepolymerized material accumulated in the section 50b can be returned to the prepolymerizable material input station 24 under the action of the pumping unit 56 through the return pipeline 58 . The final prepolymer receiver 54 is provided with an online viscometer 60 which measures the viscosity of the obtained ground homogenized prepolymerized mass prior to its unloading. An example of a viscometer is the TT-100 IECEx Viscometer which allows fast and accurate viscosity readings. Brand: AMETEK Brookfield ^TM

Viscometer 60 is connected to central processing unit 40 via feedback line 62 . As described above, the central processing unit 40 controls the rotational speed of the motor 34 and thus the linear speed of the conveyor 22, the power of the light emitters 38a and 38b, and the corresponding radiation dose of the photopolymerizable material. and can be adjusted.

The predetermined degree of prepolymerization, which affects the viscosity and other performance characteristics of the final flowable mass of the milled homogenized prepolymer, depends on the irradiation dose of the material during the photopolymerization process, which dose is determined by the prepolymerization station (38a). and the power of the light emitted from 38b). In system 20, the viscosity of the final product depends on variables such as exposure time at first station 38a, exposure time at second station, viscosity of starting materials in vessel 28, layer thickness of photopolymerizable material, and the like. dependent, it would be advantageous to experimentally select these parameters prior to setting the system to continuous, automatic operation in normal mode.

Alternatively, the required thickness of the material layer in each tray may be predetermined by calculations based on the Beer-Lambert law, which determines the attenuation of a collimated monochromatic light beam as it propagates in an absorbing medium.

That is, since the light emitted from the illuminators of the photopolymerization stations 38a and 38b decreases exponentially in the layer depth direction, it is possible to evaluate the layer thickness of the material in the tray if the light absorption constant of the component is known.

pre-curing chamber

Further details of the prepolymerization chamber 38 and its various components and related items will now be described with reference to FIGS. 3-8B. Starting with FIG. 3 , an exemplary conveyor and prepolymerization chamber for use with the system of FIG. 1 is shown in a front perspective view. System 20 may also include a closed loop conveyor 22 driven by pulleys 30 and 32 to move a plurality of trays 36a holding material through the system. The prepolymerization chamber 38 may include two light curing stations 38a and 38b, although in some embodiments a different number of stations may be used. The use of multiple prepolymerization stations 38a, 38b can be advantageous because system 20 can continue to operate in the event of a failure of one of the stations, such as station failure, maintenance, or the like.

The central processing unit 40 may be located in the prepolymerization chamber 38 and in some arrangements may be considered part of the prepolymerization chamber. The central processing unit 40 may be located, for example, between the prepolymerization stations 38a and 38b above the prepolymerization chamber 38 . The central processing unit 40 may include an internal processor (not shown) as well as a display screen 41 and buttons 43 to provide input/output capabilities to system users. Such inputs may include, for example, adjusting the intensity of the light source, adjusting the exposure time, adjusting the conveyor speed and timing, and the like. In some embodiments, central processing unit 40 may not directly control the speed or timing of conveyor 22, but rather may include interfaces for communicating with other processors that control conveyor 22. In this arrangement, the central processing unit 40 may instruct a separate conveyor processor to adjust the operation of the conveyor 22 as needed.

The first prepolymerization station 38a has a fan 35, a vent 45, a lid 39a, a handle 49a coupled to the lid 39a, and a lid with the lid attached to the prepolymerization chamber 38. It may include a hinge or bearing 47 to facilitate opening of (39a). Similarly, the second prepolymerization station 38b also includes a fan 35, a vent 45, a lid 39b, a handle 49b coupled to the lid 39b, and a lid to the prepolymerization chamber 38. It may include a hinge or bearing 47 that remains attached and facilitates opening of the lid 39b. In various arrangements, prepolymerization chamber 38 may be stationary while conveyor 22 moves various trays, such as tray 36a, through prepolymerization chamber 38 and from a material loading station.

A fan 35 and various vents 45 may facilitate air circulation through the interior regions of the prepolymerization chamber while the material is being irradiated in the first prepolymerization station 38a and the second prepolymerization station 38b, respectively. can Once again, each prepolymerization station 38a, 38b may have its own internal light source (not shown in FIG. 3) used to illuminate the material as it passes, as noted above. Each internal light source may be an array of ultraviolet LEDs, such as, for example, a 30x20 LED array.

One or more temperature sensors (not shown) may be or may be located internally to one or both prepolymerization stations 38a, 38b. Central processing unit 40 may monitor the internal temperature of stations 38a and 38b via signals from temperature sensor(s). The central processing unit 40 may independently control the speed of the fan 35 to adjust the amount of airflow to the stations 38a and 38b. The air flow regulates the internal temperature of stations 38a and 38b.

Each prepolymerization station door or lid 39a, 39b can be opened via an attached handle 49a, 49b, respectively, to provide access to the interior area of the prepolymerization station. This may enable, for example, maintenance or replacement of various inoperative or malfunctioning LEDs or other light source components. In some arrangements, central processing unit 40 may be configured to detect system events, such as when a light source is not operating properly or when one or more leads 39a, 39b are opened, so that central processing unit 40 The device may alter the operation of the system as described below.

4-7 show the conveyor and prepolymerization chamber of FIG. 3 in various alternative views for further explanation. FIG. 4 provides a top plan view, FIG. 5 provides a rear cross-sectional view, FIG. 6A provides a side cross-sectional view, FIG. 6B provides a side view, and FIG. 7 provides a side view with one prepolymerization station lid open. A rear perspective view is provided.

As shown in FIG. 7 , lid 39b of prepolymerization station 38b is opened by hinge 47 to reveal internal light source 48 . In some arrangements, the light source 48 is positioned such that when the lid 39b is closed, the light source 48 can easily illuminate the material passing underneath the interior of the prepolymerization station 38b and the lid 39b. The light source 48 may be mounted within the lid 39b so that it is readily available when the is opened. Light source 46 of prepolymerization station 38a may similarly be positioned within its prepolymerization station lid 39a.

When closed, lid 39b may rest on lip 53 surrounding opening 55 . A transparent panel 57 (eg, a panel made of glass, plexi-glass, or other suitable transparent material) is placed around the aperture to prevent polymeric material, dust, and/or other contaminants from adhering to the internal light source 48. can be placed in The transparent panel 57 can be removed to allow cleaning of the surface of the panel. Transparent panel 57 may have a refractive index of less than 1.5 so as not to interfere with ultraviolet radiation emitted from light source 48 . In some arrangements, the transparent panel 57 may be translucent but still pass ultraviolet radiation or other curing light from the light source to the polymeric material being processed within the prepolymerization station. In some arrangements, an alternative and/or additional transparent or translucent panel may be coupled to the underside of lid 39b. Identical or substantially similar features such as lip 53, aperture 55, and transparent panel 57 may also be present in polymerization station 38a.

Figure 8a shows an example of a prepolymerization chamber in a front view, while Figure 8b shows the same prepolymerization chamber in a bottom plan view. As shown in FIG. 8B, the two light sources 46 and 48 of the two prepolymerization stations are visible and can be activated to illuminate the material as they pass underneath. Although light sources 46 and 48 are shown as having 30x20 arrays of LEDs, it is understood that other sizes and shapes of arrays may be used, and alternatively other types of light sources may be used to pre-cure and cure the material. will understand

A temperature sensor 59 may be located within each prepolymerization station to measure the internal temperature during processing, and these temperature sensors 59 may be located in the central processing unit or other processing component for internal temperature monitoring and appropriate system action. can be combined For example, a first temperature sensor 59 can be located proximate to the fan 35 in one prepolymerization station and a second temperature sensor 59 can be located close to the fan 35 in another prepolymerization station. may be located in close proximity. A temperature reading may be sent from each temperature sensor 59 to a central processing unit or other system processor, which may appropriately increase or decrease airflow through the prepolymerization chamber to increase or decrease the temperature reading. Based on the , the speed of one or more fans may be adjusted accordingly.

Light intensity sensors 69 may also be located within each prepolymerization station to measure light intensity during processing, and these light intensity sensors 69 may also be used in the central processing unit or central processing unit for internal light intensity monitoring and appropriate system action. It may be coupled to other processing components. For example, four light intensity sensors 69 may be located proximate the interior corners of the prepolymerization station. Light intensity readings can be sent from each light intensity sensor 69 to a central processing unit or other system processor, which increases power to the LEDs through each of the respective pre-curing chambers as appropriate. Or, based on the light intensity readings to reduce, adjust the intensity of the associated LED or other light source accordingly.

As mentioned above, the central processing unit 40 may not function properly if the light sources 46, 48 do not function properly, if the prepolymerization stations 38a, 38b do not function properly, one of the leads 39a, 39b may be configured to detect certain system events, such as when open, a manual override input, or any other case where illumination from light sources 46 and 48 to underlying material passing through them is not properly achieved. When such a system event is detected, the central processing unit 40 can automatically take action to change the operation of the system so that overall system processing can continue even with interrupted operation of one of the prepolymerization stations.

In some arrangements, this action may include increasing the intensity of the light source of the still operational prepolymerization station. In the case of more than two prepolymerization stations, this may include increasing the intensity of some or all of the remaining operable prepolymerization stations. For example, if operation of prepolymerization station 38a is interrupted for any reason, central processing unit 40 can detect this event and emit light from light source 48 of still operational prepolymerization station 38b. The intensity of the light can be automatically doubled. In this way, while effective operation of prepolymerization station 38a is suspended, overall system 20 may continue to operate producing similar quality light-cured prepolymers. Similar adjustments can be made if operation of the prepolymerization station 38b is interrupted for any reason.

Alternatively or additionally, the action taken by central processing unit 40 may include changing the function of conveyor 22 . This may include sending a command to a separate controller for the conveyor 22 to achieve the desired function change. Such altered functionality may include, for example, longer time spent with the conveyor stationary while material is underneath and illuminated by a functioning light source. Other altered functionality of the system may also achieve the desired result of continuing overall system operation while one of the prepolymerization stations is out of operation. In various arrangements, the central processing unit 40 can also be configured to detect when a previously suspended prepolymerization station is brought back online, so that system operation can be reverted back to normal.

material result

Referring again to FIG. 1 , the feedstock material 28 fed into the input station 24 may be, for example, a liquid mixture of the components set forth in Table 1 below. The viscosity of material 28 may range from 5 to 15 cPs, and its density may range from 1.0 to 1.2 kg/1.

The prepared prepolymer material is a gelatinous homogeneous material having a viscosity in the range of, for example, 10,000 to 100,000 cPs. This material has improved adhesion, resistance to the environment, low shrinkage properties, and short set times. The combination of these properties makes it possible to achieve desired 3D printing results in less time than using conventional prepolymerized materials.

Table 1 - Characteristics of starting photopolymerizable materials used in the system

9 shows a flow diagram of an exemplary method 100 of obtaining a photopolymerized prepolymer material according to one embodiment of the present disclosure. After start step 102, first process step 104 introduces uncured liquid photopolymerizable material into each movable tray in a predetermined dosed amount controlled via a dosing valve in a manner known in the art. may include At the filling station, each tray is stopped by a command sent from the central processing unit to the conveyor motor.

In a subsequent process step 106, the conveyor belt, assuming its movement after the filling operation is complete, may be moved until the tray is aligned with the position directly below the light source of the first prepolymerization station.

In a next process step 108, the material may be exposed to a first predetermined dose of radiation at a first prepolymerization station. This can provide prepolymerization of the photopolymerizable material to a desired first degree of prepolymerization.

In the next process step 110 after pre-curing at the first station, the conveyor belt may again assume its motion and align the tray containing the pre-cured material with the light source at the second station.

Then, in a subsequent process step 112, the pre-cured material at the stage may be exposed to a second predetermined dose of radiation for final curing to achieve the desired degree of pre-polymerization.

Process steps 104-112 may proceed continuously as the conveyor continues to follow an endless looped path around the pulley.

In process step 114, the tray reaches the edge of the conveyor and changes its direction by cycling around a pulley, where the tray drops the resulting gelatinous prepolymerized material onto the first section of the separator. The resulting material may contain an uncured liquid phase.

In the next process step 116 in the separator, the uncured liquid phase flows into the second section of the separator and returns through the pipeline to the tank under the action of the pumping unit. In various embodiments, process step 116 may be optional.

In the next process step 118, the separated homogeneous prepolymerized material obtained with a preset viscosity of 10,000 to 100,000 cPs and a temperature in the range of 30 to 40° C. is passed from the first section of the separator through a funnel to a crusher or mill. , and fed from the mill to the prepolymer receiving section, where the viscosity of the prepolymer is controlled by an online viscometer. In various embodiments, process step 118 may be optional.

In process step 120, the final prepolymer is unloaded from the receiver in the direction of arrow B into the mixer of the 3D printing machine. The method then ends at end step 122 .

Application example 1

80 liters of triethylene glycol dimethacrylate (CH ₂ =C(CH ₃ )COO(CH ₂ CH ₂ O) ₃ COC(CH ₃ )=CH ₂ (TEGDMA), 40 g of phenylbis(2,4,6 A prepolymerizable mixture suitable for light prepolymerization was prepared from -trimethylbenzoyl)phosphineoxide (TPO - prepolymerization initiator) and 40 g of polyethylene glycol H(OCH ₂ CH ₂ ) _n OH(PEG). The trough filling time was 50 seconds, and the filled trough was then sent to the first prepolymerization station 38a. The station contained 600 LEDs with a maximum luminous energy of 5 W, of which only about 90% (4.5 W) were used for irradiation of the prepolymerization mixture, with an irradiation time of 27 seconds. was transported to the second prepolymerization station 38b, which contained 600 LEDs with a total luminous energy of 5 W, of which only about 90% (4.5 W) were used for irradiation of the prepolymerization mixture. was 27 seconds Therefore, the radiation dose at each station was 4.5 W x 27 seconds = about 121.5 J, and the total radiation dose was 243 J. Unloading after filtering through the sieve 50c and grinder 52 The viscosity of the final prepolymerized material was 70,000 cP In this case, since the viscosity of the final product was within the specified range, the product was suitable for use in architectural 3D printing.

Comparative Example 1

80 liters of triethylene glycol dimethacrylate (CH ₂ =C(CH ₃ )COO(CH ₂ CH ₂ O) ₃ COC(CH ₃ )=CH ₂ (TEGDMA), 40 g of phenylbis(2,4,6 A prepolymerizable mixture suitable for light prepolymerization was prepared from -trimethylbenzoyl)phosphineoxide (TPO - prepolymerization initiator) and 40 g of polyethylene glycol H(OCH ₂ CH ₂ ) _n OH(PEG) The mixture was solid PEG 4000 was filtered to remove residues and fed into trough 36a through dosing valve 44. The trough filling time was 50 seconds The filled trough was then sent to the first prepolymerization station 38a. The first prepolymerization station contained 600 LEDs with a total luminous energy of 5 W, of which only about 90% (4.5 W) were used for irradiation of the prepolymerization mixture The irradiation time was 10 seconds. The pre-polymerization mixture was transported to the second pre-polymerization station 38b, which contained 600 LEDs with a total luminous energy of 5 W, of which only about 90% (4.5 W) was used for irradiation of the pre-polymerization mixture. Irradiation time was 10 seconds Therefore, the radiation dose at each station was 4.5 W x 10 seconds = about 45 J, i.e., the total radiation dose was 90 J. Filtered through the sieve 50c and the mill 52 The viscosity of the final prepolymerized material after unloading was 9000 cP In this case, since the viscosity of the final product was outside the specified range, the product was unsuitable for use in architectural 3D printing.

Comparative Example 2

80 liters of triethylene glycol dimethacrylate (CH ₂ =C(CH ₃ )COO(CH ₂ CH ₂ O) ₃ COC(CH ₃ )=CH ₂ (TEGDMA), 40 g of phenylbis(2,4,6 A prepolymerizable mixture suitable for light prepolymerization was prepared from -trimethylbenzoyl)phosphineoxide (TPO - prepolymerization initiator) and 40 g of polyethylene glycol H(OCH ₂ CH ₂ ) _n OH(PEG) The mixture was solid PEG 4000 was filtered to remove residues and fed into trough 36a through dosing valve 44. The trough filling time was 50 seconds The filled trough was then sent to the first prepolymerization station 38a. The first prepolymerization station contained 600 LEDs with a total luminous energy of 5 W, of which only about 90% (4.5 W) were used for irradiation of the prepolymerization mixture The irradiation time was 40 seconds. The pre-polymerization mixture was transported to the second pre-polymerization station 38b, which contained 600 LEDs with a total luminous energy of 5 W, of which only about 90% (4.5 W) was used for irradiation of the pre-polymerization mixture. Irradiation time was 40 seconds Therefore, the radiation dose at each station was 4.5 W × 40 seconds = about 180 J, and the total radiation dose was 360 J. Filtering through the sieve 50 c and the mill 52 The viscosity of the final prepolymerized material after unloading was 112,000 cP In this case, since the viscosity of the final product was outside the specified range, the product was unsuitable for use in architectural 3D printing.

Therefore, it can be seen that the selection of the optimal dose of irradiation is a very important factor for the prepolymerization of the mixture composed of TEGDMA, TPO, and PEG prepared in the ratio of 80 liters, 40 g, and 40 g, respectively. It is understood that these results were obtained for a prepolymeric material composed of TEGDMA, PPO, and PEG and the content of these components in predetermined proportions.

Although the foregoing disclosure has been described in detail through illustration and illustration for purposes of clarity and understanding, it will be appreciated that the foregoing disclosure may be embodied in numerous other specific modifications and embodiments without departing from the spirit and essential characteristics of the disclosure. will be. For example, light sources other than LEDs and light sources having wavelengths different from those described above may be used. Also, the tray may have a different shape than that shown in FIG. 2 and is not necessarily flexible. In various embodiments, more than two prepolymerization stations may be used, or alternatively only one prepolymerization station may suffice. In addition, the constituents of the original photopolymerizable composition may differ from those shown in the Tables and Examples. A pulsating pump may be used instead of a dosing valve to load a dosed amount of precursor material into the tray. Various other changes and modifications may be made, and it is understood that the present disclosure should not be limited by the details described above, but should be defined by the appended claims.

Claims (22)

As a photopolymerized prepolymer manufacturing system,
a conveyor configured to move raw material from a loading area to an unloading area;
a prepolymerization chamber positioned proximate to the conveyor, having a plurality of prepolymerization stations sequentially arranged relative to the conveyor, wherein the conveyor moves the untreated material past the prepolymerization chamber, at least a prepolymerization chamber that converts a portion of it to a photopolymerized prepolymer material; and
one or more processors configured to control operation of the conveyor, the prepolymerization chamber, or both, the one or more processors configured to alter operation of the conveyor, the prepolymerization chamber, or both in response to a detected system event; Including, system. The method of claim 1,
wherein the photopolymerized prepolymer material is suitable for use in three-dimensional ("3D") printing of buildings or building components. The method of claim 2,
wherein the suitability of the photopolymerized prepolymer material is determined using a viscometer. The method of claim 3,
wherein the system is configured to emit a radiation dose in the range of 100 to 350J to untreated material in the prepolymerization chamber. The method of claim 1,
wherein each of the plurality of prepolymerization stations includes one or more light sources that illuminate the raw material as the conveyor moves the raw material past the prepolymerization chamber. The method of claim 5,
wherein each of the plurality of prepolymerization stations further includes a lid that facilitates access to one or more light sources. The method of claim 6,
wherein each of the one or more light sources is contained within a lead of its respective prepolymerization station, and wherein at least one of the one or more light sources comprises an array of light emitting diodes (“LEDs”). The method of claim 1,
wherein the detected system event comprises interrupted operation of one of the plurality of prepolymerization stations. The method of claim 8,
wherein the one or more processors are configured to measure and increase an intensity of one or more light sources at the remaining prepolymerization stations in response to interrupted operation of one of the plurality of prepolymerization stations. The method of claim 1,
wherein each of the plurality of prepolymerization stations further comprises at least one fan and one or more vents to facilitate air circulation as the conveyor moves the raw material past the prepolymerization chamber. The method of claim 10,
wherein each of the plurality of prepolymerization stations further comprises one or more temperature sensors to sense temperature and facilitate control of air flow within the prepolymerization chamber. The method of claim 11,
wherein the one or more processors are configured to adjust a speed of the at least one fan in response to a temperature sensed by the one or more temperature sensors. A prepolymerization chamber configured to convert a material to a photopolymerized prepolymer material,
a first prepolymerization station comprising a first light source configured to irradiate the material at a first intensity level as a separate conveyor moves the material past the first prepolymerization chamber; and
a second prepolymerization station comprising a second light source configured to irradiate the material at a second intensity level as a separate conveyor moves the material past the second prepolymerization chamber, the prepolymerization chamber comprising: configured to automatically increase the first intensity level when operation of the prepolymerization station ceases, and automatically increase the second intensity level when operation of the first prepolymerization station ceases; A pre-polymerization chamber comprising a. The method of claim 13,
a first lead of the first prepolymerization station facilitating access to the first light source; and
and a second lid of the second prepolymerization station facilitating access to the second light source. The method of claim 14,
wherein the first light source is contained within the first lid and the second light source is contained within the second lid, wherein both the first light source and the second light source comprise an array of LEDs. The method of claim 13,
at least one processor configured to control the operation of the prepolymerization chamber, to automatically increase the first intensity level when the operation of the second prepolymerization station ceases, and when the operation of the first prepolymerization station ceases; and at least one processor configured to automatically increase the second intensity level when The method of claim 16
The at least one processor is further configured to interface with a separate processor that controls the separate conveyor, the interfacing being configured to interface with the separate processor when the first prepolymerization station stops operating or the second prepolymerization station stops operating. and providing instructions to the separate processor to slow down the separate conveyor. The method of claim 13,
wherein the suspended operation of one of the first or second prepolymerization stations while the other prepolymerization station continues to operate comprises performing maintenance on the suspended prepolymerization station; system. The method of claim 16
a first fan of the first prepolymerization station;
a second fan of the second prepolymerization station;
a plurality of vents of the first and second prepolymerization stations - the first fan, the second fan and the plurality of vents provide air circulation as the separate conveyor moves the material past the prepolymerization chamber. - Facilitate;
a first temperature sensor of the first prepolymerization station; and
a second temperature sensor of the second prepolymerization station, the at least one processor configured to send the first fan, the second fan in response to a temperature sensed by the first temperature sensor, the second temperature sensor, or both; , or configured to adjust the speed of both. As a method for obtaining a photopolymerized prepolymer material,
introducing the uncured liquid material onto the conveyor at the loading position;
moving the conveyor until the material is located in the first prepolymerization station of the entire prepolymerization chamber;
exposing the material to a first dose of radiation at the first prepolymerization station;
moving the conveyor until the material is positioned at the second prepolymerization station of the entire prepolymerization chamber; and
exposing the material to a second dose of radiation at the second prepolymerization station, wherein the second dose of radiation cures at least a portion of the material into a photopolymerized prepolymer material. A method comprising the step of causing. The method of claim 20,
separating the cured portion of the photopolymerized prepolymer material from the remaining uncured liquid material;
returning the remaining uncured liquid material to a loading position on the conveyor;
feeding the cured portion of the photopolymerized prepolymer material through a shredder; and
The method further comprises the step of delivering the pulverized photopolymerized prepolymer to a receiving part. The method of claim 20
monitoring an internal temperature in the first prepolymerization station; and
adjusting a speed of a fan of the pre-polymerization chamber to adjust air flow within the pre-polymerization chamber in response to the monitored change in the internal temperature.

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