JP3587208B1 - Stereolithography processing reference correction method and stereolithography device - Google Patents

Abstract

An object of the present invention is to simply and accurately perform correction for matching a cutting coordinate system with a light beam coordinate system.
SOLUTION: The sintering of a powder at a predetermined portion of a layer of a powder material by irradiating a light beam to a predetermined portion thereof to form a sintered layer is repeated, and the molding formed up to that time after the formation of the sintered layer In manufacturing a molded article by inserting a step of cutting and removing a surface part and / or an unnecessary part of the object during a plurality of processes of forming a sintered layer, a calibration plate 6 set on a light beam irradiation surface in advance is manufactured. The control device that gives the mark 60 by the cutting means and the mark 61 by the light beam irradiating means to the determined point, and controls the cutting means and the light beam irradiating means, The cutting position or the light beam irradiation position is corrected based on the obtained positional deviation amount of the two kinds of marks. By actually performing the cutting and the light beam irradiation, a correction for adjusting the light beam irradiation position based on the position of the cutting edge, which is an end effector, is performed.
[Selection diagram] Fig. 1

Description

  The present invention relates to a method for correcting a processing standard and a stereolithography apparatus for stereolithography in which a three-dimensional shaped object is manufactured by sintering and hardening a powder material with a light beam.

  There is a method of manufacturing a three-dimensionally shaped object known as an optical molding method. The manufacturing method disclosed in Japanese Patent No. 2620353 (Patent Document 1) irradiates a predetermined portion of a layer of an inorganic or organic powder material with a light beam and sinters (fuses) the powder at the corresponding portion. To form a sintered layer, a new layer of powdered material is coated on the sintered layer, and a predetermined portion of the powder layer is irradiated with a light beam to sinter the powder at the corresponding location to form a lower layer. By repeating the process of forming a new sintered layer integrated with the sintered layer, a powder sintered part (three-dimensional shaped object) in which multiple sintered layers are laminated and integrated is created. There is no so-called CAM device because a light beam is radiated based on the cross-sectional shape data of each layer generated by slicing a model, which is design data (CAD data) of a three-dimensional molded object, to a desired layer thickness. Manufactures three-dimensional shaped objects with arbitrary shapes Guests can be collected by, in comparison with the manufacturing process such as by cutting, it is possible to obtain a molded article rapidly desired shape.

  By the way, unnecessary powder adheres to the periphery of the portion which is sintered and hardened by irradiating the light beam, and the adhered powder forms a low-density surface layer on a molded article due to the transmitted heat. Will form. In order to remove the low-density surface layer and obtain a three-dimensional shaped object having a smooth surface, the present applicant disclosed in Japanese Patent Application Laid-Open No. 2002-115004 (Patent Document 2) It has been proposed to insert a process of cutting and removing the surface portion and / or unnecessary portion of the formed object into the process of forming the sintered layer a plurality of times. In this case, by repeatedly performing the creation of the sintered layer and the removal of the surface portion and / or unnecessary portions of the modeled object, the surface can be finished without being restricted by the blade length of the cutting tool.

  Here, as shown in FIG. 17A, the light beam coordinate system K1 of the light beam irradiating means for sintering may be such that its scanning area is contained in a modeling tank for optical modeling. When cutting and removing processing is performed in the modeling tank 25 on the shaped object formed in the modeling tank 25, as shown in FIG. 17B, the cutting and removing coordinate system K2 and the light beam coordinate system K1 of the cutting means are used. If it is deviated, the molded object cannot be cut properly, so that the coordinate systems K1 and K2 must be matched before starting the modeling.

The light beam irradiating means is generally configured as having a scanning optical system, but including such an optical system means that a pin cushion error of the optical system or a mirror of the scanning optical system is required. As shown in FIG. 18, there is a case where the actual irradiation position S2 is deviated from the target irradiation position S1 due to the mounting position, inclination, irradiation position error due to aging, and the like. Correction is also needed.
Japanese Patent No. 2620353 JP 2002-115004 A

  The present invention has been made in view of the above points, and can easily and accurately perform correction for matching a cutting coordinate system with a light beam coordinate system and correction of an irradiation position error of a light beam irradiation unit. An object of the present invention is to provide an optical modeling processing reference correction method and an optical modeling apparatus.

  In order to solve the above problems, the stereolithography processing reference correction method according to the present invention is to form a sintered layer by sintering the powder at a corresponding location by irradiating a light beam to a predetermined location of the layer of the powder material, A new layer of a powder material is coated on the sintered layer, and a predetermined portion of the powder layer is irradiated with a light beam to sinter the powder at a corresponding location to be integrated with the lower sintered layer. The process of cutting and removing the surface part and / or unnecessary part of the modeled object created so far after the formation of the sintered layer is repeated multiple times during the process of forming the sintered layer. In manufacturing a molded article by inserting the mark, a predetermined point on the calibration plate set on the irradiation surface of the light beam, a mark by the cutting means for the cutting removal, and a light beam irradiation for irradiating the light beam Means and the cutting means and light beam The control device for controlling the irradiating means is characterized in that the cutting position or the light beam irradiation position is corrected based on the displacement between the two kinds of marks obtained from the measuring means for measuring the position of the two kinds of marks. Have. The calibration work between the cutting coordinate system and the light beam coordinate system can be automated, and by actually performing cutting and light beam irradiation, the irradiation position of the light beam is adjusted based on the position of the cutting edge which is an end effector. Corrections can be made.

  The mark by the cutting means and the mark by the light beam irradiating means may be given to different calibration plates so that there is no possibility of misidentifying the mark by the cutting means and the mark by the light beam irradiating means. After the positioning of the plate, the mark is applied and the mark position is measured.The calibration plate that applies the mark by the cutting unit and the calibration plate that applies the mark by the light beam irradiation unit are referenced by the cutting unit. By separately providing the mark, even when the position measurement is performed after the calibration plate is taken out, the position shift amount can be appropriately measured.

  By irradiating a predetermined portion of the layer of the powder material with a light beam, the powder at the corresponding location is sintered to form a sintered layer, and a new layer of the powder material is coated on the sintered layer to form a powder layer. Sintering the powder at the corresponding location by irradiating the light beam to the predetermined location to form a new sintered layer integrated with the lower sintered layer, and after forming the sintered layer, When manufacturing a model by inserting a step of cutting and removing a surface portion and / or an unnecessary portion of the model formed in a plurality of processes of forming a sintered layer, the process includes imaging means and image processing means. The imaging means in the measuring means is provided in the cutting means for removing the cutting so that the positional relationship between the cutting means and the imaging means is constant, and the imaging position of the imaging means with respect to the calibration plate set on the light beam irradiation surface. Mark the calibration points specified as And calculates the shift amount between the reference point and the mark of the image in the image from the image captured by the imaging means, may be performed to correct the light beam irradiation position based on the obtained amount of deviation. In this case, since it is not necessary to perform the cutting operation by the cutting means, the correction can be performed more easily.

  In any case, the addition of the mark to the calibration plate by the light beam irradiating means can be performed with the same power as that at the time of sintering of the powder layer. It can be carried out.

  When the mark formed by the light beam irradiating unit has a cross shape, the measuring unit configured by the imaging unit and the image processing unit obtains a shading boundary line by shading two orthogonal lines in the cross mark, If two straight lines passing through the centers of the two lines are determined from the shading boundary line and the intersection of the two straight lines is set as the center of the mark, the center position of the cross mark can be easily and accurately determined.

In addition, the shape of the mark formed on the outer side of the area on the calibration plate where the mark can be provided,
If the shape of the mark formed on the outer side of the area on the calibration plate where the mark can be provided is L-shaped or T-shaped, the area where the correction data can be obtained can be maximized.

  In addition, by repeatedly performing the addition of the mark to the calibration plate and the correction based on the amount of displacement of the mark, and reducing the number of points to which the mark is applied, it is possible to shorten the time required for processing while maintaining accuracy. Can be.

  Then, the optical shaping apparatus according to the present invention comprises a powder layer forming means for forming a layer of powder, and irradiating a predetermined portion of the uppermost powder layer with a light beam to sinter the powder at the corresponding portion to form a sintered layer. Light beam irradiating means to be formed, cutting means for cutting and removing the surface portion and / or unnecessary portion of the modeled object produced so far after the formation of the sintered layer, powder layer forming means, light beam irradiating means and cutting means And a mark provided by the cutting means at a predetermined point on the calibration plate set on the light beam irradiation surface, and a mark provided by the light beam irradiation means. Measuring means for measuring the position of the seed mark; and the control means controls the cutting position by the cutting means or the light beam irradiation by the light beam irradiating means based on the positional deviation of the two marks obtained by the measuring means. It is characterized in that the position is corrected, and a powder layer forming means for forming a layer of powder; Light beam irradiation means for sintering to form a sintered layer, cutting means for cutting and removing the surface portion and / or unnecessary portion of the modeled object produced so far after forming the sintered layer, and forming these powder layers Means for controlling the light beam irradiation means and the cutting means, and measuring the positions of the marks provided by the light beam irradiation means at a plurality of points on the calibration plate set on the light beam irradiation surface. The imaging means in the measurement means constituted by the imaging means and the image processing means is provided in the cutting means, the positional relationship between the cutting means and the imaging means is fixed, and the plurality of Poin Is defined as the imaging position of the imaging means, and the control means corrects the light beam irradiation position by the light beam irradiation means based on the shift amount between the reference point and the mark image in the image taken by the imaging means. Has other characteristics.

  The present invention can automate the correction for the calibration of the cutting coordinate system and the light beam coordinate system, and can accurately manufacture a molded article by optical molding with cutting, and moreover The cutting coordinate system and the light beam coordinate system are used to perform cutting and light beam irradiation on the calibration plate to correct the light beam irradiation position based on the position of the cutting edge which is the end effector. Can be performed with high accuracy, and at this time, the irradiation position error of the light beam irradiation means is also corrected.

  Hereinafter, the present invention will be described in detail based on an example of an embodiment. The optical forming apparatus shown in FIGS. 14 and 15 includes a powder layer forming unit 2, a light beam irradiation unit 3, a cutting unit 4, an imaging unit 5, and a control unit. The powder layer forming means 2 supplies the powder in the powder tank 23 with a squeezing blade 21 onto a stage 20 that moves up and down in a molding tank 25 by driving a cylinder. Thus, the powder layer 10 having a predetermined thickness Δt is formed on the stage 20.

  The light beam irradiating means 3 irradiates the laser beam output from the laser oscillator 30 to the powder layer 10 via an optical system 32 for adjusting a spot diameter and a focal position and a scanning optical system 31 such as a galvanometer mirror.

  The cutting means 4 is configured such that a milling head 41 is provided on the base portion of the powder layer forming means 2 via an XY drive mechanism 40. Further, the XY drive mechanism 40 is provided with an image pickup means 5 formed of a CCD or the like in a form arranged in line with the milling head 41. In FIG. 14, S is a deflection control device for controlling the oscillation, deflection and focus of the light beam, and D is an image processing device for processing the image obtained by the imaging means 5, and the imaging means 5 and the image processing device D These constitute the measuring means in the present invention.

  As shown in FIG. 15 (a), the three-dimensional shaped object is formed by using a blade 21 to apply the powder overflowing from the powder tank 23 to the surface of the molding base 22 on the upper surface of the stage 20 by raising the stage 24. At the same time as the supply, the first powder layer 10 is formed by leveling with a blade 21, and a light beam (laser) L is applied to a portion of the powder layer 10 where the powder layer 10 is to be cured to sinter the powder to form a base 22 To form a sintered layer 11 integrated with the above. Thereafter, the stage 20 is slightly lowered, and the powder is supplied again and leveled by the blade 21 to form the second powder layer 10 on the first powder layer 10 (and the sintered layer 11). Then, a light beam (laser) L is applied to a portion of the second powder layer 10 to be hardened to sinter the powder to form a sintered layer 11 integrated with the lower sintered layer 11. .

  By lowering the stage 20 to form a new powder layer 10 and irradiating the light beam L to turn the required portion into the sintered layer 11, a desired shaped object as a laminate of sintered layers is obtained. As described above, if the total thickness of the sintered layer 11 becomes a required value obtained from the cutting edge length of the tool of the milling head 41 in the cutting means 4 as described above, as shown in FIG. As described above, the cutting means 4 is once operated to cut the surface of the modeled object so far, thereby removing the low-density surface layer as an excessively sintered portion due to the powder attached to the surface of the modeled object, and removing the surface of the modeled object. The high-density portion is entirely exposed. If the tool of the cutting means 4 can perform cutting with a diameter of 1 mm, an effective blade length (length under the neck) of 3 mm and a depth of 3 mm, and the thickness of the powder layer 10 is 0.05 mm, Since the excessively sintered portion hangs down by about 0.1 mm to 0.5 mm at the time of forming, for example, the cutting means 4 is operated every time the 40 sintered layers 11 are laminated, and the cutting is performed once in the previous cutting and removing. It is also preferable to cut by overlapping about 1 mm.

  Here, as described above, if the light beam coordinate system does not match the cutting coordinate system, only the surface of the modeled object obtained by sintering by light beam irradiation is removed by cutting with the cutting means 4. Before starting modeling, the two coordinate systems must first be matched, but here, the cutting means 4 controls the position of the milling head 41 by the XY mechanism 40 and the light beam Since the irradiation position is controlled by the scanning optical system 31, it is assumed that correction is performed so that the light beam coordinate system, which can be easily corrected, matches the cutting coordinate system, and the correction value is obtained as follows.

  That is, prior to the start of stereolithography, as shown in FIG. 2, the calibration plate 6 is arranged on the stage 20 of the modeling tank 25, and the upper surface of the calibration plate 6 coincides with the moving surface of the squeezing blade 21. Adjust the height as you do. Then, as shown in FIG. 1, the cutting means 4 performs a cutting operation on a plurality of points set in advance as calibration points, thereby forming marks 60 as cutting marks on the calibration plate 6. Next, the same plural points as described above are irradiated with a light beam by the light beam irradiation means 3 to form a mark 61 on the calibration plate 6.

  Since the marks 60 and 61 are attached to the same point based on the respective coordinate systems, if the light beam coordinate system K1 and the cutting coordinate system K2 match, the marks 60 and 61 are located at the same position on the calibration plate 6. However, if the two coordinate systems K1 and K2 are displaced, the marks 60 and 61 will be placed at positions deviated.

  Therefore, the mark 60 formed at a plurality of points based on the cutting coordinate system K2 and the mark 61 formed at the same plurality of points based on the light beam coordinate system K1 are imaged using the above-described imaging unit 5, and By processing the obtained image, it is determined whether or not the mark 61 is shifted with respect to the position of the mark 60 at each point, and if so, the shift amount (Δx, Δy) is calculated. Correction data of the light beam irradiation position (correction data of the light beam coordinate system K1 with respect to the cutting coordinate system K2) is created based on the shift amount. The formation of the marks 60 and 61, the imaging, and the correction processing are preferably repeated until the amount of displacement between the marks 60 and 61 becomes equal to or less than a predetermined value.

  At this time, if the number of points to which the marks 60 and 61 are added is set to be large, not only does the light beam coordinate system K1 match the cutting coordinate system K2, but also the scan optical system 31 of the light beam irradiation means 3 and the like. The correction for the irradiation position error is also made at the same time.

  Here, the mark (cut mark) 60 by the cutting means 4 may be circular. Although an end mill can be suitably used as the cutting means 4, a circular cutting mark can be easily formed with this. In the case of a circular mark 60, the center of the mark 60 can be easily calculated as the center of a circle passing through the edge during image processing.

  On the other hand, it is preferable that the mark 61 formed by the light beam has a shape different from that of the mark 60 which is a cutting mark. This is because identification with the mark 60 can be easily performed in image processing. When the mark 60 is circular, a cross shape can be suitably used for the mark 61. As shown in FIG. 3, the calculation of the center point of the cross-shaped mark 61 in the image processing is performed by obtaining a plurality of points where the gray value changes abruptly with respect to two lines forming the cross. The left boundary line 61L, the right boundary line 61R, the upper boundary line 61U, and the lower boundary line 61D are determined as approximate straight lines, and then the intermediate straight line 61Y between the left boundary line 61L and the right boundary line 61R, and the upper boundary line 61U and the lower boundary line. What is necessary is just to obtain | require the intermediate | middle straight line 61X of 61D, and obtain | require the intersection of both intermediate | middle straight lines 61X and 61Y.

  When using a plate-like material such as a heat-sensitive paper or a glass plate on which a photosensitive paper reacting to a specific wavelength is attached to the calibration plate 6, the mark 61 is formed by lowering the power of the light beam L than at the time of molding. However, when an acrylic plate or a black alumite-treated aluminum plate is used as the calibration plate 6, the mark 61 can be formed with the light beam L having the same power as at the time of modeling. Calibration including the fluctuation due to the thermal effect of the optical system in 3 can be performed. Incidentally, when an acrylic plate is used as the calibration plate 6, the mark 61 is formed as a groove having a sectional shape shown in FIG. 4A, and when an aluminum plate subjected to black alumite treatment is used, the mark 61 is formed as shown in FIG. As shown in FIG. 5, the alumite treatment layer 65 is formed as removed.

  Incidentally, when the light beam L is a carbon dioxide gas laser and the mark 61 is formed by sintering power (for example, 300 W) at the time of molding, the mark 61 is small and small enough to fit within the camera field of view of the imaging means 5 in a state where light is condensed as much as possible. The cross mark is processed, the groove width of the groove forming the cross is measured from the image, and the center of the cross mark is determined from the center line. With such processing, the resolution of the imaging unit 5 can be used effectively.

  By the way, if the two kinds of marks 60 and 61 at each point are completely overlapped, it means that the coordinate system K2 of the cutting system and the coordinate system K1 of the laser system are coincident. If they overlap, the mark 61 (or the mark 60) may be difficult to distinguish depending on the shapes of the marks 60,61. In such a case, when the mark 60 is formed first by the cutting means 4, the mark 61 may be formed after the position measurement of the mark 60.

  Further, it is assumed that the point forming the mark 61 is offset from the point forming the mark 60 by a predetermined dimension, and it is determined whether or not the coordinate system matches at a position obtained by removing the offset from the measurement position of the mark 61. Is performed, the mark 61 does not overlap the mark 60 even when the two coordinate systems match, so that it is not difficult to distinguish between the two.

  However, when the mark 60 is circular as described above and the mark 61 is cross-shaped, the center of the cross is calculated as described above, so that the intersection of the cross overlaps with the circular mark 60. Also, there is no problem in calculating the center point. The shape of the mark 60 by the cutting means 4 and the shape of the mark 61 by the light beam may be reversed. Further, even when one of the marks 60 and 61 has a cross shape, as shown in FIG. 5, a T-shaped or L-shaped shape may be used for the outermost position among the plurality of points. The arrangement area of a plurality of points can be set to fill the entire area where the light beam can be irradiated (or the area where the milling head 41 can be moved by the XY drive mechanism 40).

  In addition, as shown in FIG. 6, the arrangement area A of a plurality of points may be determined according to the size of the modeled object P to be formed next. The time can be reduced because only necessary parts are corrected. If the arrangement area A of a plurality of points is determined around the midpoint (center of gravity) P0 of the creation position of the modeled object P, the time can be further reduced.

  In addition, when the correction operation is repeated using the calibration plate 6 after performing the correction with the obtained correction amount, even if the deviation between the marks 60 and 61 is initially large as shown in FIG. The second time after the correction is performed once, the deviation between the marks 60 and 61 is very small as shown in FIG. 9B, and the correction can be made by correcting the fine adjustment level. The number of marks 60 and 61 may be reduced, and measurement and correction may be performed with a reduced number. The time required for calibration can be reduced. However, it is desirable to estimate the shift amount of the point where the marks 60 and 61 are not added or the measurement is not performed from the shift amount at the measured point, and to estimate the shift amount for the coordinate system.

  Further, since there is a case where the deviation is small from the beginning and the correction can be made only by the correction of the fine adjustment level, the position of each of the marks 60 and 61 formed on the first calibration plate 6 is measured to perform the correction operation. When performing the correction, the value of the sum ΣΔ of the squares of the positional deviation amounts (deviation amounts) of the two at all points is obtained, and when the marks 60 and 61 are formed again on the calibration plate 6 and the correction is performed, the value of the sum ΣΔ is a predetermined value. If the value is larger than the threshold value, the marks 60 and 61 are formed and measured at m points. If the value of the sum 総 Δ is smaller than a predetermined threshold value, the marks 60 and 61 are formed at n (n <m) points. And measurement may be performed. It is possible to automatically switch between the operation of obtaining accurate correction data although it takes time and the reduction of the time required for the measurement operation in accordance with the deviation amount. In this case as well, the shift amount at the point where the formation and measurement of the marks 60 and 61 are not performed is estimated from the shift amount at the point where the formation and measurement of the marks 60 and 61 are performed. It is desirable to calculate the amount of correction from the amount of deviation.

  Further, when the correction operation is repeated using the calibration plate 6 after performing the correction with the obtained correction amount, the calibration plate 6 is replaced to perform the second formation and measurement of the marks 60 and 61. However, if different points are used in the first and second times for a plurality of set points, replacement of the calibration plate 6 becomes unnecessary. For example, as shown in FIG. 8, the marks 60 are formed at all of a plurality of set points, but the marks 61 by the light beam are formed at every other point. The marks 61 are formed for the points not formed. Since it is not necessary to replace the calibration plate 6 when repeating the correction operation, it is possible to reduce the overall time and labor required for the correction.

  Furthermore, instead of forming the marks 60 and 61 at all of the plurality of points, for example, as shown in FIG. 9, the marks 60 and 61 are formed at every other point and the marks 60 and 61 are not formed. With respect to the above, the positions of the virtual marks 60 'and 61' may be obtained from the beginning by linear approximation from the measurement positions of the marks 60 and 61 formed at the surrounding points.

  That is, if the measured positions of the left and right marks 60, 60 are (ΔXa, ΔYa) and (ΔXb, ΔYb), the position (ΔXp, ΔYp) of the intermediate virtual mark 60 ′ is (ΔXa + ΔXb, ΔYa + ΔYb) / 2, and if the measured positions of the upper and lower marks 60, 60 are (ΔXa, ΔYa) and (ΔXd, ΔYd), the position (ΔXs, ΔYs) of the virtual mark 60 ′ in the middle is ( Assuming that ΔXa + ΔXd, ΔYa + ΔYd) / 2, the virtual mark 60 ′ (ΔXp, ΔYp) = (ΔXa + ΔXb, ΔYa + ΔYb) / 2 and the virtual mark 60 ′ (ΔXr, ΔYr) = (ΔXc + ΔXd, ΔYc + ΔYd) / 2 are vertically shifted. And the virtual mark 60 ′ (ΔXs, ΔYs) = (ΔXa + ΔXd, ΔYa + ΔYd) / 2 and the virtual mark 60 ′ (ΔXq, ΔYq) = (ΔXb It is assumed that the virtual mark 60 ′ (ΔXt, Yt) having + ΔXc, ΔYb + ΔYc) / 2 on the left and right is (ΔXa + ΔXb + ΔXc + ΔXd, ΔYa + ΔYb + ΔYc + ΔYd) / 4.

  In this manner, if the estimated value of the shift amount at the point where the marks 60 and 61 are not formed is obtained, the shift amount at many points can be obtained even if the number of marks 60 and 61 formed is small. Therefore, the time required for forming the marks 60 and 61 and the time required for measuring the position thereof can be reduced.

  By using the imaging means 5 attached to the modeling device, the calibration plate 6 is imaged with the calibration plate 6 arranged on the modeling stage 20, and the marks 60 and 61 formed on the calibration plate 6 by the image processing are processed. Although the position measurement is performed, the calibration plate 6 may be removed from the stage 20 and the positions of the marks 60 and 61 on the calibration plate 6 may be measured outside the modeling apparatus. Even if the positions of the marks 60 and 61 are measured outside the modeling apparatus in order to obtain a correction value of the light beam coordinate system K1 with respect to the cutting coordinate system K2 as a reference from the displacement amount of the mark 61 with respect to the mark 60, Without any correction. Further, the position when the calibration plate 6 is set on the stage 20 may be appropriate.

  As shown in FIG. 10, the mark 61 may be provided on a calibration plate 6b different from the calibration plate 6a on which the mark 60 is provided. That is, the calibration plate 6 a is set on the stage 20, marks 60 are formed at a plurality of points set in advance by the cutting means 4, and these marks 60 are imaged by the imaging means 5 provided in the XY drive mechanism 40. The position is measured by processing. Next, the calibration plate 6b was set on the stage 20 in place of the calibration plate 6a, and marks 61 were formed at a plurality of points set in advance by the light beam irradiation means 3, and these marks 61 were provided on the XY drive mechanism 40. An image is taken by the image pickup means 5 and the position is measured by image processing. At this time, the imaging means 5 photographs the mark 61 at the same position as when the mark 60 was photographed.

  Next, a correction value of the light beam coordinate system K1 with respect to the cutting coordinate system K2 is calculated from the positional shift amount (Δx, Δy) of the mark 61 with respect to the position of the mark 60 for each point, and the correction of the light beam coordinate system is performed by this correction. Do. Preferably, thereafter, the calibration plate 6b is set on the stage 20 again to form and measure the position of the mark 61, calculate the amount of displacement (Δx, Δy) of the mark 61 with respect to the mark 60, and calculate the position of the light beam coordinate system K1. Perform re-correction. Since the two types of marks 60 and 61 are not mixed on the single calibration plate 6, it is easy to recognize the marks 60 and 61 by image processing, and there is no problem even if the marks 60 and 61 have the same shape. Therefore, image recognition for extracting the marks 60 and 61 from the image can be performed quickly.

  When using the imaging means 5 in the molding apparatus, the calibration plates 6a and 6b may be set at any positions on the stage 20, but when the position measurement of the marks 60 and 61 by the imaging means 5 or the like is performed outside the molding apparatus. As shown in FIGS. 11A, 11B, and 11C, a plurality of positioning pins 29 for positioning the calibration plates 6a and 6b are provided on the stage 20. The positioning of 6a and 6b should be performed. 11 (d) and 11 (e), a positioning pin 59 similar to the positioning pin 29 is provided on a plate 58 on which the calibration plates 6a and 6b are set. Imaging is performed in a state where the calibration plates 6a and 6b are positioned by the positioning pins 59.

  At this time, if the positioning pins 59 are provided so that the cutting coordinate system K2 and the measuring coordinate system K3 of the measuring device are coincident (or parallel), the mark 60 of the calibration plate 6a and the calibration plate 6b If the amount of positional deviation from the mark 61 is measured in the measurement coordinate system K3, the amount of deviation will coincide with the amount of deviation of the light beam coordinate system K1 with respect to the cutting coordinate system K2, or only requires addition and subtraction. Need not be corrected to rotate the cutting coordinate system with respect to the cutting coordinate system K2. That is, the displacement amount can be easily obtained simply by pressing and setting the calibration plates 6a and 6b against the positioning pins 29 and 59, respectively.

  As shown in FIG. 12, in addition to the marks 60 and 61, a plurality of reference marks 62 are formed on the calibration plates 6a and 6b by processing by the cutting means 4, and the marks 61 corresponding to the marks 60 are formed based on the plurality of reference marks 62. When calculating the amount of positional deviation, the calibration plates 6a and 6b may be set at any position on the stage 20.

  The correction operation as described above may be performed not only prior to modeling but also during modeling. In this case, the calibration plate 6 (6a, 6b) is set on the modeled object P formed up to that time. The height is adjusted so that the upper surface of the calibration plate 6 coincides with the upper surface of the powder layer 10 to be sintered, as in the case described above.

As shown in FIG. 13A, the marks 60 and 61 may be provided in a state where the calibration plate 6 (6a, 6b) is attached to the blade 21 and the calibration plate 6 is positioned above the stage 20. However, the surface of the calibration plate 6 is set to be parallel to the upper surface of the powder layer 10 to be sintered. In this case, it is difficult to set the surface of the calibration plate 6 at the same height as the upper surface of the powder layer 10 to be sintered, and as shown in FIG. The distance L1 from the scanning optical system 31 to the surface z1 of the calibration plate 6 differs from the distance L1 to the upper surface z0 of the powder layer 10, and the amount of displacement of the measured calibration plate 6 on the surface z1. Since (δx, δy) is different from the deviation amount (Δx + Δy) on the upper surface z0 of the powder layer 10 to be sintered, the following expression is used: Δx = (L1 / L2) · δx
Δy = (L1 / L2) · δy
Calculates the shift amount (Δx, Δy) on the processing surface (the surface of the powder layer 10), and performs correction based on the obtained shift amount.

  When the position of the imaging unit 5 of the measuring unit is changed by the XY driving unit 40 of the cutting unit 4 and the imaging unit 5 has a predetermined positional relationship with the cutting tool unit (milling head 41) of the cutting unit 4, the coordinates of the imaging unit 5 Since the system can be considered to match the cutting coordinate system K2, the light beam coordinate system K1 may be adjusted to the cutting coordinate system K2 in the following procedure.

That is, as shown in FIG. 16, a plurality of calibration points Q are set on the stage 20 in the modeling tank 25. These calibration points Q are defined such that, for example, the center position (pixel) of the captured image is a reference point as the imaging position. That is, one calibration point Q is set to the center position of one captured image.

  The number of the calibration points Q may be determined according to the requirement of the irradiation position accuracy of the light beam. If high accuracy is desired, a large number of calibration points Q arranged at small intervals are set. A small number of calibration points Q arranged at large intervals are set. As the imaging means 5, an imaging means having a high resolution and having a camera field of view capable of covering a range of expected displacement of the irradiation position is used.

  Then, the calibration plate 6 is set on the stage 20, and a light beam is emitted toward each of the calibration points Q to form, for example, a cross mark 61. The position of the calibration plate 6 on the stage 20 may be arbitrary. Thereafter, each calibration point Q is imaged by the imaging means 5, and as shown in FIG. 16B, data indicating how much the center of each mark 61 deviates from each calibration point Q (the center position of the captured image). I take the. At this time, both the cutting tool part and the imaging means 5 in the cutting means 4 are on the cutting coordinate system K2, and the difference between the positions (more precisely, the cutting point by the cutting tool part and the image taken by the imaging means 5) Is known, the light beam coordinate system K1 can be matched to the cutting coordinate system K2 based on the data of the deviation and the information of the known position difference. Further, an irradiation position error caused by the scanning optical system 31 or the like of the light beam irradiation unit 3 can be corrected at the same time. Performing a correction operation during molding can also be applied in this example.

  Examples of the calibration plate 6 include an acrylic plate, an aluminum plate, and thermal paper as described above, as well as a plate-like material that is colored with a color different from the object color and a portion irradiated with the light beam is discolored or decolorized. Can also be used.

It is operation | movement explanatory drawing of an example of Embodiment of this invention. It is a schematic sectional drawing which shows the arrangement position of the said calibration plate. It is a front view of an example of a mark same as the above. (a) and (b) are cross-sectional views of the calibration plate on which marks are provided. It is a front view of other examples of a mark. FIG. 4 is an explanatory diagram of an area where points forming a mark are arranged. (a) and (b) are plan views of a calibration plate provided with two types of marks. FIG. 4 is an explanatory diagram of a mark formation position. FIG. 4 is an explanatory diagram of a virtual mark. It is operation | movement explanatory drawing of another example. (a) is a cross-sectional view of a stage having positioning pins, (b) and (c) are plan views showing positioning of the calibration plate by the positioning pins, (d) is a plan view of a measuring unit having the positioning pins, and (e) is It is a side view of the measuring means which has a positioning pin. (a) and (b) are plan views of a calibration plate provided with a mark and a reference mark, respectively. (a) is a schematic sectional view of another example, and (b) is an explanatory diagram of additional correction in this case. It is a block diagram of a modeling device. (a) and (b) are schematic sectional views of the above. (a) is a plan view showing a calibration point, and (b) is an explanatory diagram of a captured image of a calibration point and a mark. (a) is an explanatory diagram of a light beam coordinate system, and (b) is an explanatory diagram of a cutting coordinate system and a light beam coordinate system. FIG. 4 is an explanatory diagram showing points to be corrected for a light beam.

Explanation of reference numerals

2 powder layer supply means 3 light beam irradiation means 4 cutting means 5 imaging means 6 calibration plate 60 mark 61 mark

Claims (10)

  By irradiating a predetermined portion of the layer of the powder material with a light beam, the powder at the corresponding location is sintered to form a sintered layer, and a new layer of the powder material is coated on the sintered layer to form a powder layer. Sintering the powder at the corresponding location by irradiating the light beam to the predetermined location to form a new sintered layer integrated with the lower sintered layer, and after forming the sintered layer, In manufacturing the molded article by inserting the step of cutting and removing the surface part and / or the unnecessary part of the molded article prepared in the above step into the sintered layer forming step a plurality of times, the calibration plate set on the light beam irradiation surface in producing the molded article For the above-mentioned predetermined point, a mark by the cutting means for the cutting removal and a mark by the light beam irradiating means for irradiating the light beam are given, and the cutting means and the light beam irradiating means are controlled. The control device measures the positions of the two kinds of marks. For stereolithography processing reference correction method characterized in that to correct the cutting position or light beam irradiation position based on the positional deviation amount of both species marks obtained from a constant section.   2. A mark provided by a cutting means and a mark provided by a light beam irradiating means are provided to different calibration plates, and after positioning of each calibration plate, a mark is provided and a mark position is measured. The processing standard correction method for stereolithography described.   The cutting means and the calibration plate for applying the mark by the cutting means and the mark by the light beam irradiating means to the different calibration plates, 2. The method according to claim 1, wherein a reference mark is separately provided.   By irradiating a predetermined portion of the layer of the powder material with a light beam, the powder at the corresponding location is sintered to form a sintered layer, and a new layer of the powder material is coated on the sintered layer to form a powder layer. Sintering the powder at the corresponding location by irradiating the light beam to the predetermined location to form a new sintered layer integrated with the lower sintered layer, and after forming the sintered layer, When manufacturing a model by inserting a step of cutting and removing a surface portion and / or an unnecessary portion of the model formed in a plurality of processes of forming a sintered layer, the process includes imaging means and image processing means. The imaging means in the measuring means is provided in the cutting means for removing the cutting so that the positional relationship between the cutting means and the imaging means is constant, and the imaging position of the imaging means with respect to the calibration plate set on the light beam irradiation surface. Mark the calibration points specified as And calculating an amount of shift between a reference point in the image and an image of the mark from an image picked up by the image pickup means, and correcting the light beam irradiation position based on the obtained amount of shift. Processing standard correction method.   The method according to any one of claims 1 to 4, wherein the mark is applied to the calibration plate by the light beam irradiating means with the same power as when the powder layer is sintered.   The mark formed by the light beam irradiating means has a cross shape, and the measuring means constituted by the imaging means and the image processing means obtains a shading boundary line by shading processing of two orthogonal lines in the cross mark, and obtains a shading boundary. The stereolithography processing according to any one of claims 1 to 5, wherein two straight lines passing through respective centers of the two lines are obtained from the line, and an intersection of the two straight lines is set as a center of the mark. Reference correction method.   The shape of the mark formed on the outer side of the area on the calibration plate where the mark can be provided is L-shaped or T-shaped, for stereolithography according to any one of claims 1 to 6. Processing reference correction method.   The method according to any one of claims 1 to 7, wherein the addition of the mark to the calibration plate and the correction based on the amount of displacement of the mark are repeatedly performed, and the number of points to which the mark is added is reduced. Processing standard correction method for stereolithography.   Powder layer forming means for forming a layer of powder; light beam irradiating means for irradiating a predetermined portion of the uppermost powder layer with a light beam to sinter the powder at the corresponding portion to form a sintered layer; Cutting means for cutting and removing the surface part and / or unnecessary part of the modeled object manufactured so far after the formation of the layer, and control means for controlling these powder layer forming means, light beam irradiation means and cutting means, and Measuring means for measuring the positions of two types of marks: a mark provided by the cutting means at a predetermined point on a calibration plate set on the light beam irradiation surface, and a mark provided by the light beam irradiation means. Wherein the control means corrects the cutting position by the cutting means or the light beam irradiation position by the light beam irradiation means based on the positional deviation of the two types of marks obtained by the measurement means. Optical shaping apparatus according to claim.   Powder layer forming means for forming a layer of powder; light beam irradiating means for irradiating a predetermined portion of the uppermost powder layer with a light beam to sinter the powder at the corresponding portion to form a sintered layer; Cutting means for cutting and removing the surface part and / or unnecessary part of the modeled object manufactured so far after the formation of the layer, and control means for controlling these powder layer forming means, light beam irradiation means and cutting means, and Measuring means for measuring the positions of the marks provided by the light beam irradiating means at a plurality of points on the calibration plate set on the light beam irradiating surface, wherein the measuring means comprises image pickup means and image processing means The imaging means in the means is provided in the cutting means, the positional relationship between the cutting means and the imaging means is fixed, and the plurality of points are defined as imaging positions of the imaging means, and the control means Optical shaping apparatus, characterized in that to correct the light beam irradiation position by the light beam irradiation means based on the shift amount between the reference point and the mark of the image in the captured image due to image unit.

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