JPH11314276A - Device and method for forming three-dimensional object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly and economically perform molding of a complex and elaborate shape in formation of a three-dimensional object. SOLUTION: The surface layer of a fluid medium 22 cured by a curing means is selectively cured in order to form a three-dimensional object 30 of a plurality of superposed and cured thin layers 30a, 30b, 30c. Coating of desired thickness is formed on the previously cured thin layer and the curing means 26 is selectively applied to height of the working face 23 of the fluid medium 22 and thereby a cured thin layer fitted to the previously cured thin layer is formed. The three- dimensional object 30 is formed of a plurality of fitted thin layers by repeating this formation and application in a plurality of times. In the forming process, coating of excess thickness is formed on at least a part of one thin layer and thereafter the excess thickness is decreased to desired thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a three-dimensional object from a curable fluid medium, and more particularly to a method for forming a three-dimensional object with high precision by stereolithography and a method for forming the three-dimensional object. It concerns the device.

[0002]

2. Description of the Related Art In the case of manufacturing a part made of plastic, it is common practice to design a part first and then to make a prototype of this part with difficulty. This requires considerable time, effort and expense. The design is then considered, and this tedious process is often repeated many times until the design is optimal. After the design is optimized, it enters production as the next step. In most productions, plastic parts are injection molded. Due to the very high design time and cost of the mold, injection plastic parts are usually only practical in large quantities. Other methods, such as direct machining, vacuum forming and direct forming, can also be used to produce plastic parts. However, these methods are usually cost-effective only if they want to be produced in a short period of time, and the parts produced are of lower quality than injection molded parts.

Recently, very good methods have been developed for creating three-dimensional objects in a fluid medium. The radiation medium that is selectively focused within the three-dimensional volume of the fluid medium selectively cures the fluid medium. A typical example of an apparatus for forming such a three-dimensional object is disclosed in U.S. Pat.
Nos. 4,041,476, 4,078,229, 4,238,840, 4,288,861 and JP-A-56-144478.

Further, curing irradiation is generated in response to data representing a large number of cross sections of a three-dimensional object to be created, and a layer of a fluid medium which can be cured by exposure to the curing irradiation is sequentially exposed to the curing irradiation. The method of forming a three-dimensional object from a plurality of sequentially adhered cross-sectional layers by curing a fluid medium by sequentially curing a fluid medium is described in Hideo Kodama, “Automatic three-dimensional shape as a method of displaying three-dimensional information. Creation Method ”(Transactions of the Institute of Electronics, Information and Communication Engineers, VOL. J64-C No. 4, April 1981), and
Alan J. Herbert, Solid Object Generation, Journal o
f Applied Photographic Engineering, VOL 8. No. 4,
August 1982.

[0005]

However, such a three-dimensional molding apparatus has many problems in terms of resolution and exposure control. The reduced control of the radiation intensity as the focal point of the radiation beam travels deeper into the fluid medium and the reduced resolution of the image of the focused spot naturally creates complex control situations. Both absorption, diffusion, dispersion and analysis methods make it difficult to machine deep in a fluid medium economically and reliably. Therefore, it is difficult to form an extremely thin layer, and it is also difficult to automatically laminate the layers.

However, to be able to move quickly and reliably from the design stage to the mold forming stage and back to final production, in particular from the computerized design of such plastic parts virtually instantaneously. There is still a long-felt need in the field of design and manufacture to move directly to mold formation, as well as to robustly mass-produce equipment economically and automatically.

[0007] Thus, those involved in the development and manufacture of three-dimensional plastic objects, etc., need to avoid the complex focusing, alignment and exposure problems of conventional three-dimensional manufacturing equipment.
We know that it would be desirable to further improve a more agile, reliable, economical and automatic means of moving quickly from the design stage to the prototype stage and back to manufacturing. The present invention satisfies all of these needs.

[0008]

SUMMARY OF THE INVENTION A method for producing a three-dimensional object according to the present invention is directed to a fluid medium curable by curing means for forming a three-dimensional object from a plurality of superposed cured thin layers. Selectively curing the surface layer of the fluid medium, wherein a coating of a desired thickness is formed on the previously cured thin layer, and the height of the working surface of the fluid medium is increased. Then, the curing means is selectively applied to form a cured thin layer attached to the previously cured thin layer, and the forming step and the applying step are repeated a plurality of times to form a plurality of attached thin layers. Forming the three-dimensional object from at least one thin layer, wherein the forming step forms an excess thickness coating on at least a portion of one thin layer, and then reduces the excess thickness to the desired thickness. Characterized by including a step of reducing Is shall.

Further, the apparatus for producing a three-dimensional object according to the present invention selectively forms a surface layer of a fluid medium curable by a curing means in order to form a three-dimensional object from a plurality of superposed cured thin layers. An apparatus for producing said object by curing, said means for forming a coating of a desired thickness on said first cured thin layer, said curing means at the working surface of said fluid medium. Means for selectively applying to form a cured lamina attached to said previously cured lamina;
And forming the three-dimensional object by repeating the operations of the forming means and the applying means a plurality of times to form a plurality of attached thin layers, wherein the forming means comprises at least a portion of the thin layer. Forming an excess thickness coating thereon and thereafter reducing the excess thickness to the desired thickness.

Further, the apparatus according to the present invention is an apparatus for designing and directly creating a three-dimensional object, comprising means for designing and displaying the three-dimensional object and a thin section of the three-dimensional object. Means for generating a graphical image output defining the first layer; means for automatically providing a thin first layer of the reactive fluid medium; and positioning the first layer of the reactive fluid medium on the work surface; and Automatically exposing to curing radiation emitted in response to said graphical image output, thereby forming a thin cross-section of the reacted medium corresponding to said graphical image output; and a plurality of reactive media. In order to automatically provide a thin layer of a plurality of layers and to automatically create the three-dimensional object from a plurality of layers, each layer adheres to a previous layer while successively exposing each layer, and successive layers are formed. Means for automatically forming, and different faces of the object, the plurality of layers And it is characterized in that and means for exposing the curing radiation while offering continuously.

A method according to the present invention is a method for designing and directly creating a three-dimensional object, wherein the three-dimensional object is designed, displayed on a diagram, and designed by a computer. Generating graphical image output data defining a thin cross-section of the reactive fluid medium, providing a thin first layer of a reactive fluid medium to a work surface, and curing the first layer with curing radiation generated in response to the graphical image output data. Forming a thin section of the reacted medium corresponding to the graphic image output data, providing a plurality of thin layers of the reactive medium, and automatically creating the three-dimensional object from the plurality of layers. While exposing successive layers to allow, successive layers of reacted medium attached to the immediately preceding layer are formed in succession, providing different faces of the object in succession of the plurality of layers. Consists of each step exposed to curing radiation during And it is characterized in and.

[0012] The present invention provides a method of forming a cross-section laminate of adjacent objects one by one on a surface of a fluid medium capable of changing its physical state in response to appropriate synergistic energy. A new and improved apparatus for creating three-dimensional objects is provided. The layers that are stacked one by one are automatically tightly integrated when they are formed, forming the desired three-dimensional object.

For example, in a preferred embodiment, the present invention utilizes computer generated graphic ideas in combination with lithography. That is, in order to apply lithography technology to the production of three-dimensional objects and to produce three-dimensional objects directly from computer instructions, computer-aided design (CAD) and computer-aided (CAM) at the same time.
The invention can be used to form templates and molds during the design phase of product development, or as a manufacturing device, or for the formation of pure artistic objects.

"Three-dimensional modeling" as used herein is a method and apparatus for making objects by "printing" thin layers of a curable material, for example, a material that can be cured by ultraviolet light, one above the other. A solid cross section of an object is formed on the surface of the liquid using a moving spot beam of programmed UV light that illuminates a surface or layer of the liquid that can be cured by UV (ultraviolet). Thereafter, the object is moved away from the surface of the liquid in a programmed manner by one thickness, after which the next cross-section is formed and adhered to the layer immediately before it to form part of the object.
This process is continued until the entire object is formed.

With the method according to the invention, objects of almost any shape can be produced. Complex shapes are easier to make by using a computer.

Of course, the radiation for curing the curable fluid medium may be irradiation of particles (such as an electron beam), spraying the material through a mask, or chemical reaction by ink jet, or radiation other than ultraviolet light. Irradiation may be of any other type of suitable, synergistic energy (such as curing by interaction of the radiation with the material) to the curable fluid medium, such as.

In practicing the present invention, a fluid medium that can be cured in response to a predetermined energy is first contained in any suitable container, and a layer of a cross section is formed in the fluid medium. Define a defined work surface that can be used.
Thereafter, an appropriate type of synergistic energy, such as a spot of ultraviolet light, is applied as a graphic pattern to the identified working surface of the fluid medium to form a thin solid layer on this surface. Each layer automatically represents a number of adjacent layers that represent adjacent cross-sections of the three-dimensional object to be made, as they are formed, and are automatically overlapped with one another to integrate the layers and to achieve the desired tertiary order. Form the original object. Here, when the fluid medium is cured and the solid material is formed as a thin laminate on the work surface, the appropriate platform to which the first laminate is secured is typically mounted by any suitable actuator, typically all micro Move away from the work surface in a programmed manner under the control of a computer or the like. In this way, the solid material initially formed on the working surface is moved away from this surface,
New liquid flows into the work surface. A portion of this new liquid is converted to a solid material by the programmed UV light spot to form a new laminate (layer), which is bonded to the adjacent material, ie, the previously formed layer, by adhesion. Is done. This process continues until the entire three-dimensional object is formed. The formed object can then be removed from the container and another object identical to the original object, or an entirely new object created by a computer, created.

The stereolithographic method and apparatus of the present invention have many advantages over currently used methods for making plastic objects. That is, the method of the present invention does not need to design, create drawings, or create drawings and tools for machining. Designers can work directly on computers and 3D modeling equipment, and when satisfied with the design graphically displayed on the computer's output screen, can produce parts for direct inspection. If the design has to be modified, this can easily be done through the calculator, and then another part can be made to make sure that the design change was correct. If a design requires several parts with interacting design parameters, the entire design of the part must be quickly changed and recreated, and the entire assembly repeatedly inspected, if necessary. Therefore, the method of the present invention is more useful.

After the design is complete, the production of the part can begin immediately, avoiding the weeks and months required between design and production. The final production speed and cost of parts should be similar to the cost of current injection molding for short-term production, with lower labor costs than with injection molding. Injection molding is economical only when a large number of identical parts are required. No tools needed,
Since the set-up time for production is very short, three-dimensional modeling is useful for short-term production. Similarly, this method facilitates design changes and the manufacture of custom parts. Due to the ease with which parts can be manufactured, this 3D modeling allows many parts where metal or other material parts are currently used,
You will be able to use plastic parts. In addition, plastic models can be made quickly and economically before deciding to make an expensive metal or other material product.

Accordingly, the stereolithography method and apparatus of the present invention has long existed for CAD or CAM systems that can rapidly, reliably, accurately and economically design and manufacture three-dimensional plastic parts and the like. It responds to the requests made.

The above and other objects and advantages of the present invention will become more apparent from the following detailed description of the drawings.

[0022]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and 2 are flowcharts showing a basic method and apparatus of the present invention for creating a three-dimensional object by three-dimensional printing.

With other types of synergistic energy, such as ultraviolet (UV) radiation, electron beam, visible, non-visible radiation, ink jet or reactive chemicals applied through a suitable mask Numerous liquid state chemical materials are known that can be induced to change into fixed polymeric plastics. UV curable chemicals are currently used as inks for high speed printing, as adhesives in the coating process of paper and other materials, and in other specialized fields.

3D modeling is a technique for reproducing a graphic object by using various methods. Currently, for example,
There are photo reproduction, xerography and microengraving as used in the manufacture of microelectronic circuits. Computer generated graphics displayed on a plotter or cathode ray tube are also in lithographic form, and the image is a computer encoded image of the object.

Computer-aided design (CAD) and computer-aided manufacturing (CAM) are techniques that apply the power of computers to the design and manufacturing process. CA
A typical example of D is in the field of electronic printed wiring design. A numerically controlled milling machine is known as a typical example of a CAM that draws a design of a printed wiring board when design parameters are input as data to a computer and a plotter.
Given the appropriate programming instructions, the calculator and the milling machine machine the metal parts. Both CAD and CAM are rapidly growing technologies.

It is a primary object of the present invention to utilize computer-generated graphic ideas in combination with UV-curable plastics to simultaneously execute CAD and CAM, and to direct three-dimensional objects directly from computer instructions. It is to make. The present invention is called three-dimensional modeling, and can be used for forming a model and a prototype in a design stage of product development, or as a manufacturing device, or as an artistic shape.

FIG. 1 broadly describes the three-dimensional molding method of the present invention. Step 10 of FIG. 1 represents the creation of individual layers representing a cross section of the three-dimensional object to be formed. Step 11 is usually performed only if step 10 is performed correctly, but the successively formed adjacent laminae are combined to form the desired three-dimensional programmed object of the apparatus. And selectively cure.
For this reason, the three-dimensional modeling apparatus of the present invention has the following features:
In response to appropriate synergistic energies, such as electron beams, other particle irradiation, ink jets, or chemicals applied by spraying through a mask adjacent to the surface of the fluid, the physical A three-dimensional object is created by creating a cross-sectional pattern of the object to be formed on a selected surface of a fluid medium, such as a UV-curable liquid, which can change the physical state. Successive adjacent layers representing successive adjacent cross-sections of the object are automatically formed and integrated to create a stepwise layered or laminar configuration of the object, and during such forming process, the fluid medium A three-dimensional object is formed and lifted from the substantially planar or sheet surface.

The method described above is described in more detail in FIG. In FIG. 2, step 12 calls for containing a fluid medium that can solidify in response to a predetermined reactive energy. Step 13 applies this energy as a graphic pattern to the selected fluid surface to form a thin solid discrete layer on that surface. Each layer represents an adjacent cross section of the three-dimensional object to be created. It is desirable that each such layer be made as thin as possible during the practice of the present invention in order to maximize the resolution of the three-dimensional object being formed, to reproduce accurately and to reduce fabrication time. For this reason, the ideal theoretical state is that the object is created only on the selected working surface of the fluid medium, resulting in an infinite number of layers, each layer having a thickness greater than zero. The goal is to have a hardened depth that is only slightly greater (eg, less than 1 mm). With such a thin layer, the accuracy of the formed object can be improved, and a molded portion having no support on the surface can be formed. Of course, in actual use of the present invention, each layer is a thin layer, but forms a cross-section to provide adequate bonding when adhering to an adjacent laminate that defines the other cross-section of the formed object. It should be as thick as it can hold.

In step 14 of FIG. 2, successive layers are superimposed upon each other as they are formed, and the various layers are integrated to form the desired three-dimensional object. In the normal practice of the invention, when the fluid medium cures and a solid material is formed to form one layer, the layer is moved away from the working surface of the fluid medium and a new alternative to the previously formed layer is formed. The next layer is formed in the liquid, so that each successive layer is superimposed (by the natural adhesion of the cured fluid medium) with all other cross-sectional layers. Thus, the process of manufacturing such a cross-sectional layer is repeated many times until the entire three-dimensional object is formed. Thereafter, the object is removed from the liquid and the device is ready to produce another object. This object may be the same as the previous object,
Alternatively, a completely new object can be obtained by replacing the program for controlling the three-dimensional printing apparatus.

FIGS. 3 to 8 show various apparatuses suitable for carrying out the three-dimensional printing method shown in the flow charts of FIGS. 1 and 2. FIG.

As previously mentioned, "stereolithography" is a method and apparatus for making solid objects by successively "printing" thin layers of curable material, eg, UV curable material, one above the other. is there. A programmable moving spot of UV light illuminating the surface or layer of the UV curable liquid
The beam is used to form a solid cross section of the object on the surface of the liquid. Thereafter, in a programmed manner, the object is moved away from the surface of the liquid by one thickness to form the next cross-section and adhere to the immediately preceding layer to form the object. This process is continued until the entire object is formed.

With the method according to the invention, almost any type of object shape can be produced. Complex shapes can be more easily created by using a computer to generate program instructions and send this program signal to the 3D modeling device.

A three-dimensional shaping apparatus of an embodiment which is presently considered to be preferred is shown in a side sectional view in FIG. A container 21 is filled with a UV curable liquid 22 and the like, and a selected work surface 23 is selected.
Is determined. A controllable radiation source, such as ultraviolet light 26, creates an ultraviolet spot 27 in the plane of surface 23. Movement of a mirror or other optical or mechanical element (not shown) that is part of light source 26 may cause spot 27 to move across surface 23. The position of the spot 27 on the surface 23 is
Is controlled by A movable lifting table 29 inside the container 21 can be selectively raised and lowered. The position of the table 29 is controlled by the computer 28. In operation of this device, a three-dimensional object 30 is formed by stepwise stacking the integrated layers as shown at 30a, 30b, 30c.

The surface of the UV curable liquid 22 is maintained at a constant height within the container 21 and has a spot 27 of UV light or other suitable type of intensity that has the strength to cure and convert the liquid to a solid material. The reactive energy travels across the work surface 23. When the liquid 22 cures to form a solid material, the lift 29 initially located just below the work surface 23
Is lowered from this work surface in a programmed manner by a suitable actuator. In this way, the initially formed solid material will be below the surface 23 and fresh liquid 22 will flow into the surface 23. A portion of this new liquid is converted to a solid material by the programmed UV light spot 27, and the new material is bonded to the underlying material by adhesion. This process is continued until the entire three-dimensional object 30 is formed. Thereafter, the object 30 is removed from the container 21 and the apparatus is ready to make another object.
Thereafter, another object can be created, or a new object can be created by replacing the computer 28 program.

The curable liquid 22, such as a UV curable liquid, must have several important properties, such as: (A) It must cure quickly with available UV light sources so that the time to form the object is (short) to a practical length. (B) Adhesive, successive layers must adhere to each other. (C) When the viscosity is sufficiently low and the platform moves the object,
Fresh liquid material must flow quickly to the surface. (D) The layer formed by absorbing UV must be appropriately thin. (E) a solvent which is moderately soluble in a liquid state solvent, is moderately insoluble in the same solvent in a solid state, and after an object is formed, a UV-curable liquid and a liquid partially cured from the object Must be able to be washed off. (F) It should be as non-toxic and non-irritating as possible.

The cured material must have the desired properties once it is in the solid state. In other words, it is the same as when other plastic materials are used normally, and is related to the application. Color, fabric, strength, electrical properties,
Flammability and flexibility should be considered. In addition, the cost of the material is often also important.

Practical three-dimensional modeling device (example is shown in FIG. 3)
UV curable materials used in currently preferred embodiments of Loctite Ltd.
Potting Compound 363, which is a modified acrylate manufactured by the Company.
A method of making this typical UV curable material is described in U.S. Pat.
No. 4,100,141.

That is, the above-mentioned UV curable material can be cured by free radical copolymerization using countless known initiators as free radicals. Examples of such initiators include peroxides such as hydrogen peroxide; organic peroxides such as benzoyl methyl ketone peroxide; azo compounds such as 2,2'-azobis (isobutyronitrile) Hydroperoxides such as cumene hydroperoxide, t-butyl hydroperoxide and methyl ethyl ketone hydroperoxide; peresters such as t-butyl perbenzoate and t-butyl peracetate that hydrolyze to peracid compounds; benzophenone, benzoin ether And the like. The light source 26 produces a spot 27 of UV light that is small enough to form the desired details of the object and strong enough to quickly cure the UV curable liquid used to a practical extent. I do. The source 26 is configured to turn on and off, and that the focusing spot 27 can be programmed to move across the surface 23 of the liquid 22. For this reason,
As the spot 27 moves, it hardens the liquid 22 to a solid and creates a solid pattern on the surface, much as a chart recorder or drafter draws a pattern on paper using a pen. Draw.

The light source 26 of the stereolithographic apparatus of the presently preferred embodiment is a short arc mercury lamp of 350 watts in the housing, and the light output of the housing is a 1 mm diameter UV transparent optical fiber bundle (shown in the figure). No) focused on the edge. The bundle end closer to the mercury lamp was water cooled and an electronically controlled shutter plate was provided between the lamp and the bundle end so that light passing through the bundle could be turned on and off. The bundle was 1 m long and the light output was fed into a lens tube with a quartz lens to focus the UV into a spot. Light source 26 is capable of producing a spot slightly smaller than 1 mm in diameter and has a long wave UV intensity of about 1 watt / cm ³ .

In the apparatus of FIG. 3, the surface 23 is maintained at a constant height, and after the object is removed, means for replenishing the material is provided so that the focal spot 27 is sharply focused on a constant focal plane. Stop and maximize resolution in forming thin layers along the work surface. In this case, the work surface 23
The focus is formed such that a high intensity area is obtained, diverging rapidly to low intensity, limiting the depth of the curing process,
It is desirable to have the thinnest cross-section layer appropriate for the object to be formed. This is best achieved using a short focal length lens, with the source 26 as close to the working surface as possible, to maximize divergence at the focal cone entering the fluid medium. As a result, the resolution is substantially increased.

The light source 26 is moved using an HP-9872 digital plotter (not shown) manufactured by Hewlett-Packard Company. The lens tube is mounted on the pen cartridge of the plotter and the plotter is driven by the computer 28 using normal graphics instructions. The shutter is operated using a computer command,
Controlled by a Type 7 data acquisition / control device.

Physically other forms of light source 26 or their equivalents can be used. Scanning can be performed using an optical scanner, which eliminates the need for optical fiber bundles and digital plotters. Ultimately, UV lasers are better light sources than short arc lamps. The speed of the stereolithography process is mainly limited by the intensity of the light source and the response of the UV curable liquid.

The object 30 to be formed is supported and held by the lifting table 29 and is moved up and down. Typically, after one layer has been formed, the object 30 is moved beyond the level of the next layer (overdip into the liquid medium) to form a solid on the surface 23 where the solid has formed. To allow the liquid 22 to flow into the temporary space, and then return to the correct height for the next layer. As a result, the liquid 22 that has flowed into the void retreats as the tide rises, forming a layer having a predetermined thickness. This allows automatic lamination of very thin layers. The requirements for the lift 29 are that it can be moved as programmed at the appropriate speed and accuracy, and that it be robust to withstand the weight of the object to be formed. Further, it is preferable that the position of the elevator can be finely adjusted manually at the time of setting and when removing the object.

The lifting platform 29 of the embodiment shown in FIG.
A table attached to a plotter (not shown). This plotter is driven under the program control of the computer 28 by an HP-34797 data acquisition / control device with an internal digital-to-analog converter.

The computer 28 of the three-dimensional printing apparatus of the present invention basically has two functions. First, it helps the operator design a three-dimensional object in such a way that it can be created. Second, it translates the design into appropriate commands for 3D modeling and sends the commands to form the object. In some applications, there is an object design, and the only action of the calculator is to issue the appropriate command or command.

In the ideal case, the operator can design the object and view it on the CRT screen of the computer 28 in a three-dimensional image. When the operator has finished the design, he instructs the computer 28 to create the object, and the computer issues appropriate instructions for the three-dimensional fabrication.

In the example used in the embodiment of the present invention, the computer 28 is an HP-P9816 and uses the basic operation system. In this system, the operator uses the HP Graphic Language (3497).
A) and the basic language commands. The operator must also set an appropriate exposure time and speed for the UV cure time. In order to operate this apparatus, an image of an object is created, and a program for driving a three-dimensional modeling apparatus to create the object is created.

The lifting table 29 is driven by a mechanical system, a pneumatic system,
Either hydraulic or electrical, and optical or electronic feedback control can be used to precisely control its position. The elevator 29 is typically made of glass or aluminum, but any material can be used as long as the cured plastic material adheres.

In some cases, the computer 28 becomes unnecessary,
If only a simple shape is to be produced, a simpler dedicated programming device can be used. Instead,
Calculator 28 may simply execute instructions generated by another more complex calculator. For example,
An object can be created using some solid modeling equipment, and the object to be formed can be designed first using another equipment.

A computer controlled pump (not shown) can be used to maintain a constant level of liquid 22 at work surface 23. The necessity is for the following reasons. That is, when the liquid is exposed, the liquid contracts due to a change in its volume, and the liquid level changes. In addition, when the lift 29 moves into the liquid, the volume of the liquid changes, thereby changing the liquid level. The thickness of the liquid layer is determined by the depth of the layer immediately before it is formed below the liquid level, so if the liquid level is not kept constant, the thickness of the actually formed layer will be the desired thickness. This is because the thickness of the layer is different from that of the first layer, and a layer having an accurate thickness cannot be formed. Drive the fluid pump using a well-known suitable liquid level detection device and feedback circuit, or
Alternatively, the liquid displacement device is driven to drive a solid rod (not shown) which moves out of the fluid medium when the lift platform is moved deeper into the fluid medium, thereby smoothing the amount of change in the fluid volume. Thus, a constant fluid level can be maintained on the surface 23. Alternatively, the light from the light source 26 may be moved with respect to the detected liquid level 22 to automatically maintain a sharp focus on the work surface 23. All of these alternatives can be easily achieved with ordinary software working with the calculator 28.

After the three-dimensional object 30 is formed, the elevating platform 29 is raised, and the object is removed from the platform. Typically, this is followed by ultrasonic cleaning of the object in a solvent, such as acetone, which does not dissolve the hardened solid medium but dissolves the liquid state of the uncured fluid medium. Thereafter, the object 30 is exposed to intense ultraviolet light, typically 200 watts / inch (about 78.10 m).
(7 watts / cm) under a UV curing lamp to complete the curing process.

Further, when practicing the present invention, a plurality of containers 21 can be used. Each container holds a different type of curable material and can be automatically selected by the three-dimensional modeling device. In this case, the various materials may be different colored plastics or may have both insulating and conductive materials available for the various layers of the electronic component.

Another embodiment of the present invention will be described with reference to other drawings, and the same reference numerals are used throughout the drawings for the same parts as those in FIG. 3 which describes the preferred embodiment of the present invention.

FIG. 4 shows another three-dimensional printing apparatus. In this case, the UV curable liquid 22 or the like
Floating above the V-permeable liquid 32. The liquid 32 is immiscible with the curable liquid 22 and does not wet it. As an example, for the intermediate liquid layer 32, ethylene, glycol or heavy water is suitable. In the device of FIG.
Instead of submerging the object in the fluid medium as shown in the apparatus of the above, the object 30 is pulled up from the liquid 22.

The UV light source 26 of FIG. 4 focuses the spot 27 on the interface between the liquid 22 and the immiscible intermediate liquid layer (release liquid) 32. The UV radiation passes through a suitable UV transparent window 33 made of quartz or the like supported on the bottom of the container 21. The curable liquid 22 is provided as a very thin layer on top of the immiscible layer 32, and thus should ideally be made a very thin layer, so as to limit the depth of cure, Instead of relying solely on the like, there is the advantage of directly limiting the layer thickness. For this reason, the formation area is further sharply limited, and the apparatus of FIG.
Certain surfaces are formed more smoothly. Further, the UV curable liquid 22 requires less volume, making it easier to replace one curable material with another.

The device of FIG. 5 is similar to the device of FIG.
There is no movable UV light source 26, and instead of a programmed source 26 and focusing spot 27, a collimated wide UV light source 35 and a suitable aperture mask 36 are used. The aperture mask 36 is brought as close as possible to the work surface 23 so that the collimated light from the UV source 35
To expose the work surface 23 and continue to create adjacent layers, as in the embodiment of FIGS. But,
By using the fixed mask 36, which represents the shape of the cross section of the object to be formed, the three-dimensional object can be of a constant cross section. When changing this cross-sectional shape, a new mask 36 corresponding to that particular cross-sectional shape must be replaced and properly aligned. Of course, the mask can be changed automatically by providing a web of mask (not shown) that is successively moved to align with surface 23.

FIG. 6 also shows a three-dimensional printing apparatus similar to that described with reference to FIG. However, instead of the light source 26 and the focal spot 27, a cathode ray tube (CRT)
38, an optical fiber faceplate 39 and a water or other template layer 40. For this reason, the image output from the computer 28 to the CRT 38 forms a formed image on the surface of the UV emission luminous body of the tube, where the optical fiber layer 39 and the template layer 4
0 and enters the working surface 23 of the fluid medium 22. In all other respects, the apparatus of FIG. 6 forms successive cross-sectional layers that define the desired three-dimensional object to be formed, exactly as in the previously described embodiments.

FIGS. 7 and 8 show a three-dimensional shaping device in which the lift 29 has additional degrees of freedom so that different surfaces of the object 30 can be exposed for other construction methods. . Similarly, this stereolithography method can be used as a method of "adding" one part to an object, using a lift 29 to pick up and position another part for auxiliary stereolithography processing. Can be. In this regard, the apparatus shown in FIGS. 7 and 8 is the same as FIG. 3, but in the apparatus of FIGS. 7 and 8 the elevator 29 is manually or automatically controlled about a pivot pin or hinge member 42. The difference is that it has a second degree of freedom to rotate. In this regard,
FIG. 7 shows the adjustable platform 29a in a normal position, FIG. 8 shows the platform 29a rotated 90 °,
For this reason, the auxiliary structure 41 additionally formed by three-dimensional modeling can be selectively formed on one side of the three-dimensional object 30. Practical three-dimensional modeling devices have additional components and subsystems beyond those previously described for the devices schematically illustrated in FIGS.
For example, a practical device has a frame and a housing and a control panel. Additionally, there may be means to shield the operator from excess UV and visible light, and may have means to allow the object 30 to be seen during formation. Practical devices include safety measures to control ozone and harmful smoke and high pressure safety protection and interlocking devices. Such practical devices also have means for effectively shielding sensitive electronic circuits from noise sources.

As described above, the solid modeling method of the present invention can be carried out by using many other devices. For example, instead of the UV light source 26, an electron source, a visible light source, a laser light source, a short arc light source, a high energy particle light source, an X-ray source or other radiation source can be used, which responds to a specific type of reactive energy. Any suitable fluid medium that cures, such as a photopolymerizable material, can be used. For example, alpha octadecyl acrylic acid, which has been slightly polymerized using UV light, can be polymerized using an electron beam. Similarly, poly (2,3-dichloro-
1-propyl acrylate) can be polymerized using an X-ray beam.

[0060]

According to the present invention, there is provided a three-dimensional molding method and apparatus.
There are many advantages over currently used methods for manufacturing plastic objects. The method of the present invention does not require the creation of design layouts and drawings, nor does it require the creation of working drawings and tools. The designer can work directly with the computer and the 3D modeling device, and when satisfied with the design displayed on the output screen of the computer, can manufacture the part for direct consideration.
When a design must be changed, the change can be easily made through a computer, and then another part can be made to verify that the change was correct. If a design requires several parts with interacting design parameters, the design of all parts can be quickly changed and recreated. The method of the present invention is further useful because the entire assembly can be made and inspected iteratively, if necessary.

After the design is complete, production of the part can begin immediately, thus avoiding weeks and months between design and production. The final production speed and cost of parts should be similar to the cost of current injection molding for short-term production, and labor can be lower than with injection molding. Injection molding is economical only when many identical parts are required. Stereolithography is useful for short-term production. This is because no tools are required and the set-up time for production is very short. Similarly, with this method, design changes and custom parts are easily obtained. Because of the ease with which parts can be made, 3D modeling allows plastic parts to be used in many places where metal or other material parts are now used. Further, a plastic model of the object can be quickly and economically made before deciding to manufacture more expensive metal or other material parts.

Although the various three-dimensional modeling devices for carrying out the present invention have been described above, they have a common idea of drawing a substantially two-dimensional surface and pulling up a three-dimensional object from this surface. it is obvious. The present invention addresses a long-felt need for CAD and CAM devices that can rapidly and reliably, accurately, and economically design and manufacture three-dimensional plastic parts and the like.

While the specific form of the invention has been illustrated and described, it will be clear that various changes can be made within the scope of the invention. Therefore, the present invention is not limited only to the description of the claims of the present application.

[Brief description of the drawings]

FIG. 1 is a flowchart showing the basic idea used to carry out the three-dimensional printing method of the present invention.

FIG. 2 is a flowchart similar to FIG. 1;

FIG. 3 is a block diagram combined with a cross-sectional view of a presently preferred embodiment of an apparatus embodying the invention.

FIG. 4 is a sectional view of a second embodiment for carrying out the present invention;

FIG. 5 is a sectional view of a third embodiment of the present invention.

FIG. 6 is a sectional view of still another embodiment of the present invention.

FIG. 7 is a partial cross-sectional view of a case where the three-dimensional printing apparatus of FIG. 3 is modified so as to incorporate a lift having many degrees of freedom.

FIG. 8 is a sectional view similar to FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Container 22 UV curable liquid 23 Work surface 26 Light source 28 Computer 29 Lifting table 30 Object

Claims (4)

[Claims] A plurality of superposed cured thin layers (30a, 3a).
0b, 30c) to form a three-dimensional object (30) by selectively curing the surface layer of the fluid medium (22) curable by the curing means. Forming a coating of a desired thickness on the previously cured thin layer, and setting the curing means (2) at the height of the working surface (23) of the fluid medium (22).
6) selectively applying to form a cured thin layer attached to the previously cured thin layer, repeating the forming step and the applying step a plurality of times,
Forming the three-dimensional object (30) from a plurality of deposited thin layers, wherein the forming step forms an excess thickness coating on at least a portion of one thin layer, Reducing the excess thickness to the desired thickness. 2. A plurality of superposed cured thin layers (30a, 3a).
0b, 30c) to form a three-dimensional object (30) by selectively curing the surface layer of the fluid medium (22) curable by the curing means. Means for forming a coating of a desired thickness on the thin layer which has been first hardened, the hardening means (2) at the height of the working surface (23) of the fluid medium (22).
Means for selectively applying 6) to form a cured thin layer adhered to said previously cured thin layer, and repeating the operations of said forming means and said applying means a plurality of times to produce a plurality of adhered thin layers Forming said three-dimensional object (30) by forming a coating having an excessive thickness on at least a portion of the thin layer, and then forming the excess thickness. An apparatus comprising means for reducing said desired thickness. 3. An apparatus for designing and directly creating a three-dimensional object, comprising: means for designing and displaying the three-dimensional object in a diagram; and outputting a graphic image defining a thin cross section of the three-dimensional object. Means for automatically providing a thin first layer of the reactive fluid medium and positioning the first layer of the reactive fluid medium on a work surface; and outputting the first layer to the graphical image output. Means for automatically exposing to the curing radiation emitted in response to the light, thereby forming a thin cross section of the reacted medium corresponding to the graphical output; and automatically forming a plurality of thin layers of the reactive medium. Means for automatically forming a plurality of layers by adhering each layer to a previous layer while successively exposing each layer so that the three-dimensional object can be automatically created from the plurality of layers. And during providing the different layers of the object sequentially with the plurality of layers. Means for exposing to curing radiation. 4. A method of designing and directly creating a three-dimensional object, wherein the three-dimensional object is designed, displayed on a diagram, and defines a thin section of the three-dimensional object designed by a computer. Creating graphical output data, providing a thin first layer of a reactive fluid medium to a work surface, exposing the first layer to curing radiation generated in response to the graphical output data, Forming a thin cross section of the reacted medium corresponding to the graphic image output data, providing a plurality of thin layers of the reactive medium, and enabling automatic creation of the three-dimensional object from the plurality of layers. Successively forming a plurality of layers of reacted medium adhered to the immediately preceding layer while exposing the layers of the same, exposing different surfaces of the object to curing radiation during the successive provision of the plurality of layers. A method comprising the steps of exposing.