DETAILED DESCRIPTION OF THE INVENTION

[0030] Hereinafter, an intermittent material feed type variable-lamination rapid prototyping process and apparatus using a linear thermal cutting system according to the present invention will be explained in detail with reference to the accompanying drawings.

[0031] FIG. 1 is a perspective view showing the constitution of an intermittent material feed type variable-lamination rapid prototyping apparatus using a linear thermal cutting system according to the present invention; and FIG. 2 is a conceptual view of a material according to the present invention.

[0032] As shown in FIGS. 1 and 2 , an intermittent material feed type variable-lamination rapid prototyping apparatus 100 comprises a collapsible leg 20 and a friction roller 30 for feeding a sheet material 10 , a conveyor belt 40 for transferring the sheet material 10 , a linear thermal cutting system 60 for processing the sheet material 10 , and a prototyping jig 80 for manufacturing a product.

[0033] Driving speeds of the friction roller 30 and the conveyor belt 40 and operations of the linear thermal cutting system 60 in respective axis directions can be controlled by a computer 70 electrically connected with them.

[0034] The collapsible leg 20 includes a plurality of pivotable plates 22 connected with one another through linkage at their intersections, and elastic bodies 21 mounted at the intersections for serving to absorb a shock.

[0035] The top of the collapsible leg 20 is provided with a supporting plate 23 that is also connected through the linkage with the pivotable plates. A plurality of sheet materials 10 are stacked on the supporting plate 23 .

[0036] Further, a driven gear 31 attached to one end of the friction roller 30 is rotated in engagement with a driving gear 41 of the conveyor belt 40 . The driving gear 41 is connected with a direct current motor 42 of which a driving speed and supplied electric power are controlled by the computer 70 .

[0037] At this time, the friction roller 30 faces the collapsible leg 20 with the stacked sheet materials 10 interposed therebetween and comes into close contact with a surface of an uppermost one of the stacked sheet materials 10 by means of upward elastic force of the elastic bodies 21 mounted in the leg 20 .

[0038] Therefore, the uppermost one of the sheet materials 10 that is in close contact with the friction roller 30 can be intermittently fed onto the conveyor belt 40 in accordance with a rotational direction of the friction roller 30 .

[0039] Moreover, the conveyor belt 40 transfers the sheet material 10 fed by the friction roller 30 from one side of the conveyor belt to the other side thereof, and is supported by two pairs of supports 43 for ensuring stable driving of the conveyor belt 40 . The conveyor belt 40 repeatedly takes each temporary standby (stop) state for cutting the sheet material 10 during the operation of the conveyor belt 40 .

[0040] Two pairs of spacing rods 50 are installed widthwise on both sides of the conveyor belt 40 in a state where each pair of spacing rods is disposed on one of the sides thereof. The spacing rods 50 can cause the sheet material 10 to be lifted upward and in parallel with the ground from the conveyor belt 40 by means of a spacing plate 53 to which lower ends of the spacing rods 50 are vertically fixed and a hydraulic cylinder 51 for lifting and lowering the spacing plate 53 in parallel with the ground.

[0041] At this time, the hydraulic cylinder 51 receives hydraulic pressure from a hydraulic pressure supply and regulator 52 connected with one side thereof, and the hydraulic supply adjuster 52 is electrically connected with the computer 70 which in turn can control whether the hydraulic pressure is supplied by the hydraulic supply adjuster 52 .

[0042] When the sheet material 10 transferred by the conveyor belt 40 reaches a position where the spacing rods 50 are installed, the computer 70 shuts off the electric power, which is supplied to the direct current motor 42 of the conveyor belt 40 , through an onboard inverter (not shown) in the computer 70 so that the sheet material 10 can be in the standby state.

[0043] Then, the sheet material 10 is lifted upward from the conveyor belt by means of the spacing plate 53 and the spacing rods 50 lifted by the hydraulic cylinder 51 .

[0044] The lifted sheet material 10 is processed using the linear thermal cutting system 60 which can cut the material while controlling processing parameters, such as a processing length and width, a lateral gradient, a cutting speed, and a hot wire temperature, during the processing based on cutting operation data generated in the computer 70 .

[0045] The computer 70 is operated based on a Windows operating system and can beforehand perform modeling of a product to be manufactured later by executing a 3-dimensional CAD program installed therein and then perform a slicing operation for slicing the modeled product into a plurality of sheets.

[0046] Through such operations, the computer 70 generates the cutting operation data by which movements of the linear thermal cutting system 60 in the respective axis directions can be controlled, and causes the linear thermal cutting system 60 to perform a more precise cutting operation.

[0047] Meanwhile, the sheet material 10 is cut into a unit shaped-sheet 11 by the linear thermal cutting system 60 operated in such a way. A predetermined amount of adhesive is applied to one side of the unit shaped-sheet 11 which in turn is bonded to and laminated on the other side of another unit shaped-sheet that geometrically corresponds thereto.

[0048] At this time, the bonding and laminating of the unit shaped-sheets 11 are performed on the prototyping jig 80 so that a single product can be prototyped. The prototyping jig 80 includes two partitions 82 constructing a two-story structure, and a laminating rod 81 vertically coupled with the partitions 82 .

[0049] The laminating rod 81 can be broken into a plurality of unit pieces 81 a. Each piece 81 a has one end with female threads formed therein, and the other end with complementary male threads formed thereabout. Thus, the pieces 81 a can be fastened to one another. Accordingly, the height of the laminating rod 81 can be adjusted. As a result of continuous fastening of the unit pieces 81 a , products can be prototyped regardless of the quantity of unit shaped-sheets 11 .

[0050] Moreover, as shown in FIG. 2 , the sheet material 10 includes one laminating hole 10 a which is included in the processed unit shaped-sheet 11 but is located out of the processing range. The laminating hole 10 a can be fitted over the laminating rod 81 so that the unit shaped-sheet 11 to be laminated on the prototyping jig 80 can remain in place and thus maintain the shape of the product.

[0051] Furthermore, the sheet material 10 is formed with four spacing holes 10 b placed at respective ones of four corners of the sheet material 10 in addition to the laminating hole 10 a . Since the diameter of each of the spacing rods 50 is increased toward a lower end thereof, the spacing rods 50 are fitted into the respective spacing holes 10 with predetermined gap so that a processing position of the sheet material 10 can be fixed.

[0052] FIG. 3 is a conceptual view of the material processing using the linear thermal cutting system according to the present invention, and FIG. 4 is a block diagram illustrating the control process of the linear thermal cutting system according to the present invention.

[0053] As shown in FIGS. 3 and 4 , the linear thermal cutting system 60 includes a main spindle 61 , a pivotable rod 62 hingedly connected with one end of the main spindle 61 , a pair of translating rods 63 of which one ends are linked with both ends of the pivotable rod 62 , and a hot wire 64 connected between the other ends of the translating rods 63 .

[0054] At this time, the main spindle 61 can rotate 360° in a clockwise or counterclockwise direction. The pivotable rod 62 hingedly connected with the main spindle 61 is pivotable on a hingedly connected portion of the pivotable rod. The pivoting angle of the pivotable rod is about −65° to +65° with respect to a vertical plane in which the main spindle 61 is included.

[0055] Furthermore, the pair of translating rods 63 which are linked with both the ends of the pivotable rod 62 can be translated in forward and backward directions according to the pivoting movement of the pivotable rod 62 .

[0056] The hot wire 64 disposed between the translating rods 63 can cut the sheet material 10 into the unit shaped-sheet 11 . The hot wire 64 may be a wire material for radiating electric resistance heat resulting from an electric current applied thereto, or may be replaced by a cutting laser that is widely used for a cutting operation, such as a CO ₂ laser or ruby laser.

[0057] The linear thermal cutting system 60 constructed as such is a 4-axis operation control type in which the operations in the respective axis directions can be controlled based on the cutting operation data generated by the CAD program installed in the computer 70 . The temperature of the hot wire 64 can also be controlled based on physical properties of the sheet material 10 to be processed.

[0058] Hereinafter, an intermittent material feed type variable-lamination rapid prototyping process using the linear thermal cutting system according to the present invention will be explained with reference to the accompanying drawings.

[0059] FIG. 5 is a flowchart illustrating the intermittent material feed type variable-lamination rapid prototyping process using the linear thermal cutting system according to the present invention.

[0060] As shown in FIG. 5 , the prototyping process generally comprises five steps. The respective steps of the process will be described below.

[0061] The computer 70 operated based on the Windows operating system generates the cutting operation data which control the cutting operation, after performing the modeling of the product. More specifically, the computer 70 performs the modeling of the product by using the 3-dimensional CAD program and performs the slicing operation for beforehand slicing the product to be prototyped into the plurality of sheets by executing a program for automatically generating cutting paths, which is installed in the computer.

[0062] Further, after a profile of the product to be prototyped is restored, the product is sliced again to obtain intermediate sections. Then, the cutting operation data are finally generated based on unit shape data produced from the intermediate sections (S 100 ).

[0063] Subsequently, a feeding speed of the friction roller 30 that rotates in engagement with the driving gear 41 of the conveyor belt 40 is controlled so that the sheet materials 10 supported by the collapsible leg 20 are intermittently fed onto the conveyor belt 40 .

[0064] At this time, the collapsible leg 20 supports and raises the plurality of sheet materials 10 stacked thereon by the elastic bodies 21 disposed at the intersections of the pivotable plates 22 , so that each of the sheet materials 10 is caused to come into close contact with the friction roller 30 . Thus, the rotation of the friction roller 30 causes the materials 10 to be fed onto the conveyor belt 40 one by one (S 200 ).

[0065] Thereafter, the sheet material 10 transferred by the conveyer belt is stopped and remains in the standby state by shutting off the electric power to the conveyor belt 40 . Then, the sheet material 10 is lifted upward from the conveyor belt in parallel with the ground by lifting the spacing rods 50 .

[0066] Here, since the sheet material 10 is formed with the spacing holes 10 b corresponding to the spacing rods 50 , the spacing rods 50 are lifted and then fitted into the respective spacing holes 10 b.

[0067] At this time, since the diameters of the spacing rods 50 are increased toward the lower ends thereof, the spacing rods 50 are fitted into the spacing holes 10 b not to fully penetrate therethrough so that the upward spaced material 10 can be caught by and fixed around the spacing rods (S 300 ).

[0068] The upward lifted material 10 is cut by the linear thermal cutting system 60 of which the operations in the respective axis directions are controlled based on the cutting operation data generated in the computer 70 .

[0069] As described above, the linear thermal cutting system 60 is a 4-axis control type link mechanism in which the pivotable rod 62 is connected with the one end of the rotatable main spindle 61 , the pair of translating rods 63 are linked with both the ends of the pivotable rod 62 , and the hot wire 64 is provided between the translating rods 63 .

[0070] The hot wire 64 is a kind of wire material for radiating the electric resistance heat resulting from an electric current applied thereto, or the CO ₂ laser or ruby laser for use in a cutting operation. Such a hot wire 64 can cut the sheet material 10 into the unit shaped-sheet 11 through the interlocked operations in the respective axis directions (S 400 ).

[0071] Then, the adhesive is applied to one sides of the unit shaped-sheets 11 subjected to the cutting operation, which in turn are bonded to the other sides of other unit shaped-sheets that geometrically correspond thereto. The product can be prototyped by sequentially laminating the unit shaped-sheets 11 on the prototyping jig 80 in such a way.

[0072] At this time, the laminating rod 81 formed on the prototyping jig 80 is fitted into the laminating holes 10 a formed in the respective unit shaped-sheets 11 so that the shape of the prototyped product can be correctly maintained (S 500 ).

[0073] In the prototyping apparatus 100 constructed as such, an electric motor may be substituted for the hydraulic cylinder 51 .

[0074] Further, the hot wire 64 may be any one selected among high-temperature plasma, heat gas and a heat beam, in addition to the wire material for radiating the electric resistance heat resulting from the electric current applied thereto, or the CO ₂ laser or ruby laser for use in a cutting operation.

[0075] According to the aforementioned intermittent material feed type variable-lamination rapid prototyping process and apparatus using the linear thermal cutting system of the present invention, the intermittent and sequential feed of the materials and the cutting operation of the materials can be controlled by the computer. Consequently, there is an advantage in that the operation time can be relatively shortened and thus workability can be improved.

[0076] Further, the operations of the linear thermal cutting system in the respective axis directions are controlled by the computer on the basis of the cutting operation data in order to cause the processing parameters such as the processing length and width and the gradient to be controlled during the processing. Therefore, there is an advantage in that more precise processing can be achieved.

[0077] Moreover, since there is no need for a post treatment for the processed unit shaped-sheets, additionally required operation time can be shortened.

[0078] Particularly, since a complex 3-dimensional shape that cannot be manufactured by a 3- or 5-axis cutting operation can be manufactured in a relatively short period of time, there is an advantage in that the prototyping process and apparatus according to the present invention can be adapted to manufacture of commercial characters as well as various kinds of industrial or engineering parts.

[0079] Although the present invention has been described in connection with the preferred embodiment, it will be understood by those skilled in the art that various changes and modifications may be made thereto without departing from the spirit and scope of the invention. Therefore, the appended claims are construed as covering such changes and modifications falling within the scope of the invention.

[0080] All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirety.