RU2189079C2 - Device for manufacturing three-dimensional objects - Google Patents

Abstract

FIELD: prototyping three-dimensional objects such as parts and units of machines and mechanisms. SUBSTANCE: device has container filled with liquid medium capable of changing its physical condition under the action of chosen radiation, perforated platform for mounting object to be manufactured, perforated-platform and container displacement system, radiation source, and control computer; novelty is that device is provided with system for splitting radiation into beams and with deflection yokes; control computer functions to produce computer image of object being manufactured in the form of set of transversal sections. EFFECT: enhanced precision of object reproduction. 3 dwg

Description

 The invention relates to the field of rapid prototyping of three-dimensional objects using computer data (Rapid Prototyping), in particular to laser stereolithography.

 The invention can be used in many industries for the manufacture of master models of parts and components of machines and mechanisms, as well as for obtaining copies of consumer goods for the purpose of visualization. In addition, such models can be used as accessories in the manufacture of real parts.

 A device / 1 / is known for the manufacture of three-dimensional objects by forming cross-sections of an object on the surface of a liquid medium capable of changing its physical state under the influence of the selected synergistic radiation, bombardment by a particle beam or chemical exposure.

 It is also known an improved device / 2 / for the manufacture of three-dimensional objects by forming cross-sections of the object on the surface of a liquid medium, capable of changing its physical state under the action of the selected synergistic radiation, bombardment by a particle beam or chemical exposure, in which information about the object is used to reduce distortion arising in the manufacture of an object, increasing the resolution, strength, accuracy, reproduction speed of an object even with a very complex shape.

 The last device of all analogues is closest to the claimed sample and is selected as a prototype.

 The disadvantage of this system is that in the manufacture of large enough objects (for example, more than 250 • 250 • 250 mm), distortions in the shape and size of the reproduced cross section may occur due to changes in the size of the radiation spot when the reproduction plane (liquid surface) does not coincide with the focal surface of the optical circuit .

 Figure 1 shows the course of the radiation beam - 1, the plane of reproduction of the cross section (surface of the liquid medium) - 2, the focal surface of the optical circuit - 3, δ is the deviation between the plane of reproduction of the cross section and the focal surface of the optical circuit, R is the distance between the deflecting system and the surface liquid medium, and - the maximum deviation of the beam.

 The value of δ is greater, the greater the maximum deviation of the beam (a) and can be reduced by increasing the distance R between the deflecting system and the surface of the liquid medium. Thus, developers of devices for making copies of three-dimensional objects using laser stereolithography are forced to significantly increase the distance R in order to provide the necessary accuracy while increasing the maximum possible size of the manufactured object. This can be achieved either by increasing the size of the device, or by introducing additional elements into the optical circuit.

 The purpose of the invention is to increase the accuracy of products manufactured by laser stereolithography without significantly increasing the overall dimensions of the device and increasing the productivity of the installation.

 This goal is achieved due to the fact that the playback area of the section is divided into n = i • j parts in two mutually perpendicular directions (figure 2).

 In FIG. 2 shows the cross-section of the manufactured object - 1, divided into n parts - 2, cross-linking zones of individual sections - 3, i and j - the number of horizontal and vertical sections, respectively, a • b - the total cross-sectional area.

 Each of the sections is reproduced on the surface of a liquid medium by a separate radiation beam controlled by a separate deflecting system.

 Moreover, due to a decrease in the maximum deviation of the beam a from the vertical, the required fidelity is achieved without increasing the distance R (Fig. 1). In addition, the installation performance is increased, there is a physical limit to the speed of deflection of the beam, due to the mass inertial characteristics of the elements of the deflection system. The use of several deviation systems at the same time allows for greater plant productivity without reaching the limit of the deviation speed.

 A device is proposed, characterized in that it is equipped with a system for dividing radiation into n individual beams and a system for tuning the radiation wavelength.

 Figure 3 presents a diagram of the proposed device, consisting of a container with a liquid medium capable of changing the physical state under the influence of the selected radiation - 1; a perforated platform on which the manufactured object is fixed with a vertical movement system for this platform - 2; n radiation deflection systems in two mutually perpendicular horizontal directions - 3; the source of the selected radiation - 4; radiation separation systems into n individual beams - 5; control computer - 6; systems of vertical movement of the container with liquid medium - 7; radiation wavelength tuning systems - 8; device control unit - 9.

 A computer image of the manufactured object created in any CAD system is represented as a set of cross sections by planes perpendicular to the selected vertical axis. The shape of the outer contour and the inner hatching of each cross section of the object is programmatically divided into n parts. Each of these parts is reproduced on the surface of a liquid medium by a separate beam obtained by dividing the source 4 beam using a radiation separation system 5 controlled by one of the deflecting systems 3, to which information about the shape of the external contour and the internal hatching of each section section is transmitted. Boundary stitching of individual sections of the cross section is also performed at the program level, and after reproducing the necessary trajectories, a solid film is formed on the surface of the liquid medium, having the shape of a whole cross section of the manufactured object. This film, attached to the platform, is immersed in the liquid medium to a depth equal to the thickness of the next layer, and the shape of the next section is reproduced on the surface. The solid film of the next section firmly sticks to the previous one due to changes in the physical state of the medium. Thus, after the reproduction of the entire set of cross sections in a liquid medium is completed, a solid copy of the manufactured object is formed.

 The system of tuning the wavelength of the radiation of the source - 8 (figure 3) allows to increase the productivity of the device. The increase in productivity of the device is based on the dependence of the absorption coefficient of the medium on the radiation wavelength. Thus, by controlling the radiation wavelength in the corresponding range, it is possible to control the depth of radiation penetration into the medium, and hence the thickness of the formed layer. Most of the manufactured objects have a shape containing sections with the same cross-sectional shape. Similar sections can be formed with a larger layer thickness, which will allow to produce an object in fewer steps.

Literature
1. Pat. U.S. 4,575,330 dated 03/11/86.

 2. Pat. USA 5.059.359 dated 10.22.91.

Claims (1)

 A device for the manufacture of three-dimensional objects, containing a container with a liquid medium capable of changing the physical state under the influence of the selected radiation, a perforated platform for fixing the manufactured object, a system for moving the perforated platform vertically, a system for vertically moving a container with a liquid medium, a radiation source and a control computer the fact that it is equipped with a system for separating radiation into beams and deflecting systems, while the control computer is intended to create a computer image of the manufactured object in the form of a set of cross sections, the shape and inner hatching of each of which is divided into parts, the radiation separation system into beams is designed to separate the radiation source radiation beam into individual beams, into deflecting systems designed to control the beams, it is transmitted information about the shape and hatching of each of the cross-sections of the computer image of the manufactured object, the surface of the liquid medium is intended to reproduce making a separate bunch of parts of the form and internal hatching of cross-sections of a computer image of the manufactured object and the formation on the said surface of a solid film having the shape of a corresponding cross section, the perforated platform is designed to fix the said solid film to it, sticky solid films make it possible to produce a three-dimensional object.

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