JP2020059897A - Defect-inspecting method - Google Patents

Abstract

To provide a defect-inspecting method capable of detecting defects when a molded product is molded.SOLUTION: A defect-inspecting method repeats the following steps to inspect defects in a molded product 83 molded on a molding stage 3: a step S2 of laminating a powder layer 5b on the molding stage 3; and a step S3 of solidifying a predetermined part of the powder layer 5b to form a solidified layer 83b, the method having a step S4 of scanning the solidified layer 83b with an inspection laser 7. In the scanning step (step S4), reflected light intensity of the inspection laser 7 is recorded together with a scanning position of the inspection laser 7, thereby detecting the defects in the solidified layer 83b and identifying the position of the defects.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a defect inspection method.

  For example, Patent Document 1 discloses a method of forming a molded article on a modeling stage by repeating a step of stacking a powder layer on a modeling stage and a step of solidifying a predetermined portion of the powder layer. There is.

Japanese Patent No. 6177412

  In the technique disclosed in Patent Document 1, the powder material may remain in an unsolidified state at a part of a predetermined portion of the powder layer, and a defect may occur in the solidified layer. Therefore, the formed product may be inspected for defects by scanning it with x-rays or the like. However, with the method of scanning a defect by scanning with x-rays or the like, the defect cannot be detected when the modeled object is formed.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a defect inspection method capable of detecting a defect when forming a modeled object.

  One mode to achieve the above object is to form a powder on the modeling stage by repeating a step of stacking a powder layer on the modeling stage and a step of solidifying a predetermined portion of the powder layer to form a solidified layer. A defect inspection method for inspecting a defect of a shaped object, comprising the step of scanning the solidified layer with an inspection laser, wherein in the scanning step, the reflected light intensity of the inspection laser is set to a scanning position of the inspection laser. And the defect is detected in the solidified layer and the position of the defect is specified.

  The defect inspection method according to the present invention includes a step of scanning the solidified layer with a laser for inspection, and in the step of scanning, records the reflected light intensity of the laser for inspection together with the scanning position of the laser for inspection to detect defects in the solidified layer. The position of the defect is specified while being detected. That is, it is possible to detect a defect when a modeled object is modeled.

  ADVANTAGE OF THE INVENTION According to this invention, the defect inspection method which can detect a defect at the time of modeling a molded article can be provided.

It is an overall view of the defect inspection apparatus according to the present embodiment. It is a partially expanded sectional view of a modeled object. It is a flowchart which shows the defect inspection method which concerns on this Embodiment. It is a graph which shows an example of the measurement result of reflected light intensity. It is a surface photograph of a solidified layer.

  Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and drawings are appropriately simplified.

  First, with reference to FIG. 1 and FIG. 2, the configuration of an apparatus (defect inspection apparatus according to the present embodiment) that can perform the defect inspection method according to the present embodiment will be described. FIG. 1 is an overall view of the defect inspection device according to the present embodiment. FIG. 2 is a partially enlarged cross-sectional view of the modeled object.

  As shown in FIG. 1, the defect inspection apparatus 1 includes a main body 2, a modeling stage 3, a vertical movement mechanism 3a, a powder supply stage 4, a vertical movement mechanism 4a, a coater 6, a laser oscillator 71, a mirror 72, and a sensor 73. Prepare Note that FIG. 1 shows the powder material 5, the inspection laser 7, and the modeled article 83 in addition to the defect inspection apparatus 1. Further, as shown in FIG. 2, the modeled article 83 includes a plurality of solidified layers 83b. In addition to FIG. 2, the main body 2, the modeling stage 3, and the plurality of powder layers 5b are illustrated in FIG.

  It should be noted that the right-handed xyz orthogonal coordinates shown in FIG. 1 and other drawings are, of course, convenient for explaining the positional relationship of the components. Usually, the positive direction of the z-axis is vertically upward and the xy plane is the horizontal plane, which is common between the drawings.

  As shown in FIG. 1, the main body 2 is a structure having an upper surface parallel to the xy plane. A modeling space 23 and a powder supply space 24 are formed in the main body 2. The modeling space 23 and the powder supply space 24 each have an opening on the z-axis positive direction side.

  The bottom of the modeling space 23 is the upper surface of the modeling stage 3. The modeling stage 3 is always in contact with the side surface of the modeling space 23. The modeling stage 3 is arranged parallel to the xy plane. The modeling stage 3 can slide in the modeling space 23. A vertical movement mechanism 3a is connected to the modeling stage 3. The modeling stage 3 can be moved up and down in the modeling space 23 using the vertical movement mechanism 3a.

  The bottom of the powder supply space 24 is the upper surface of the powder supply stage 4. The powder supply stage 4 is always in contact with the side surface of the powder supply space 24. The powder supply stage 4 is arranged parallel to the xy plane. The powder supply stage 4 can slide in the powder supply space 24. A vertical movement mechanism 4 a is connected to the powder supply stage 4. The powder supply stage 4 can be moved up and down in the powder supply space 24 by using the vertical movement mechanism 4a.

  The powder material 5 is filled in the powder supply space 24. The powder material 5 can be melted using a melting laser. The powder material 5 melted using the melting laser solidifies when cooled. The powder material 5 is, for example, an inorganic material such as a metal material or a ceramic material, or an organic material such as a resin.

  As shown in FIG. 1, a coater 6 is placed on the upper surface of the main body 2. The coater 6 is movable along the upper surface of the main body 2 in a direction parallel to the xy plane. By moving the coater 6 along the upper surface of the main body 2, the powder material 5 can be leveled in a direction parallel to the xy plane.

  The modeling space 23 is filled with the powder material 5 using the coater 6. Specifically, first, the powder supply stage 4 is moved up while the powder material 5 is filled up to the opening of the powder supply space 24, and a part of the filled powder material 5 is moved more than the upper surface of the main body 2 by z. Push it out in the positive direction of the axis. The coater 6 arranged on the x-axis positive direction side of the powder supply space 24 is moved toward the x-axis negative direction side of the modeling space 23. When the coater 6 is moved, the powder material 5 extruded from the powder supply space 24 can be filled in the modeling space 23 while being leveled in a direction parallel to the xy plane.

  When the powder material 5 is filled in the modeling space 23 using the coater 6, the modeling stage 3 is lowered by a predetermined amount. When the modeling stage 3 is lowered by a predetermined amount, the volume of the modeling space 23 increases by a predetermined amount. When the modeling space 23 is filled with the powder material 5 in the same amount as the volume increased by using the coater 6, the powder material 5 can be filled up to the opening of the modeling space 23.

  Therefore, the volume of the powder material 5 extruded from the powder supply space 24 when the powder material 5 is filled in the modeling space 23 using the coater 6 is equal to or larger than the volume of the modeling space 23 that is increased by lowering the modeling stage by a predetermined amount. Is. The powder material 5 filled up to the opening of the modeling space 23 forms a powder layer 5b as shown in FIG.

  A predetermined region of the powder layer 5b formed in the modeling space 23 is irradiated with a melting laser (not shown). The melting laser is oscillated from the laser oscillator 71 and reflected by the mirror 72. By adjusting the arrangement of the mirror 72, it is possible to adjust the traveling direction of the melting laser and irradiate the entire region of the powder layer 5b with the melting laser. The powder layer 5b irradiated with the melting laser is melted. A predetermined region of the powder layer 5b is melted by irradiation of a melting laser and then cooled and solidified to form a solidified layer 83b.

  After the solidified layer 83b is formed, the modeling stage 3 is lowered by a predetermined amount to form the next powder layer 5b in the modeling space 23. Then, a predetermined region of the next powder layer 5b is irradiated with a melting laser to form the next solidified layer 83b. In this way, the modeled article 83 having a plurality of solidified layers 83b is formed. The chain double-dashed line shown in FIG. 1 indicates the shaped product 8 to be manufactured. A plurality of solidified layers 83b are further formed on the z-axis positive direction side of the modeled article 83 to manufacture the modeled product 8.

  As will be described later in detail, in the defect inspection method according to the present embodiment, the defect of the solidified layer 83b is inspected using the inspection laser 7 oscillated from the laser oscillator 71. The inspection laser 7 is a laser in which the output of the melting laser is suppressed to about 1/10. Since the inspection laser 7 has a weaker output than the useful laser, it can be scanned without melting the solidified layer 83b. Further, the melting laser and the inspection laser 7 can be oscillated from a common laser oscillator 71. Therefore, it is not necessary to separately prepare an oscillator for oscillating the inspection laser 7.

  When the solidification layer 83b is irradiated with the inspection laser 7, a part of the reflected light of the inspection laser 7 passes through the mirror 72 and is incident on the sensor 73. When the solidified layer 83b has a defect, the intensity of the reflected light is different between the defect portion and other portions. Therefore, the defect in the solidified layer 83b can be found by scanning the entire solidified layer 83b using the inspection laser 7 and measuring the intensity of the reflected light.

  Next, the defect inspection method according to the present embodiment will be described in detail with reference to FIG. FIG. 3 is a flowchart showing the defect inspection method according to this embodiment. As shown in FIG. 3, in the defect inspection method according to the present embodiment, first, a step of raising the modeling stage 3 to a predetermined start position (step S1) is performed.

  In step S1, the vertical movement mechanism 3a is operated to raise the modeling stage 3 to a predetermined start position. The predetermined start position is a position where the upper surface of the modeling stage 3 is on the z-axis negative direction side of the upper surface of the main body portion 2 by one thickness of the powder layer 5b. When the modeling stage 3 is raised to a predetermined start position, the modeling space 23 has a thickness equal to that of one powder layer 5b.

  Next, a step of spreading the powder material 5 (a step of stacking the powder layer 5b on the modeling stage 3) (step S2) is performed. Step S2 includes a step of raising the powder supply stage 4 and a step of operating the coater 6. In the step of raising the powder supply stage 4, the powder supply stage 4 is raised by a predetermined amount so that the powder material 5 corresponding to the volume of one layer or more of the powder layer 5 b is supplied from the powder supply space 24 to the upper surface of the main body 2. Push it up. Then, in the step of operating the coater 6, the extruded powder material 5 is spread in the modeling space 23 while being leveled in the direction parallel to the xy plane to form the powder layer 5b.

  Next, a step of melting and solidifying the powder material 5 (a step of solidifying a predetermined portion of the powder layer 5b to form a solidified layer 83b) (step S3) is performed. In step S3, a predetermined region of the powder layer 5b is irradiated with a melting laser to melt the powder material 5. When the irradiation of the melting laser is completed, the melted powder material 5 is naturally cooled and solidified. The powder material 5 that is solidified after melting forms a solidified layer 83b.

  Next, a step of irradiating the inspection laser 7 (a step of scanning the solidified layer 83b with the inspection laser 7) (step S4) is performed. In step S4, the entire upper surface of the solidified layer 83b formed in step S3 is scanned using the inspection laser 7. When the inspection laser 7 is applied to the upper surface of the solidified layer 83b, part of the reflected light passes through the mirror 72 and is incident on the sensor 73.

  The intensity of the reflected light that has entered the sensor 73 is recorded in a recording unit (not shown). An example of the reflected light intensity recorded is shown in FIG. As shown in FIG. 4, when a predetermined numerical value range is set as a specified value and the reflected light intensity is outside the specified value, it is determined that there is a defect (step S5). FIG. 5 is a surface photograph of the solidified layer. The arrow shown in FIG. 5 indicates a defective portion. As shown in FIG. 5, when a defect portion is present in the solidified layer 83b and the entire upper surface of the solidified layer 83b is scanned using the inspection laser 7, the portion where the reflected light intensity is out of the specified value is shown in FIG. Occurs in

  When it is determined that there is a defect in step S5, the position where the defect is generated is specified from the record of the irradiation position (scanning position) of the inspection laser 7 and is stored (step S6). In the example shown in FIG. 4, the reflected light intensity is outside the specified value at time t. That is, it can be specified that a defect has occurred in the portion irradiated with the inspection laser 7 at the time point t.

  Next, it is determined whether or not the occurrence rate of the defective portion detected in step S6 is less than or equal to a specified value (step S7). When the occurrence rate of the defective portion is equal to or higher than the specified value, the step of spreading the powder material 5 (step S8) is performed. Step S8 includes a step of raising the powder supply stage 4 and a step of operating the coater 6. In the step of raising the powder supply stage 4, the powder supply stage 4 is raised and the powder material 5 corresponding to the volume of the defective portion of the solidified layer 83b or more is extruded from the powder supply space 24 to the upper side of the upper surface of the main body 2. . Then, in the step of operating the coater 6, the extruded powder material 5 is spread over the defective portion of the solidified layer 83b while being leveled in the direction parallel to the xy plane.

  Next, a step (step S9) of melting and solidifying the powder material 5 at the defective portion is performed. In step S9, a melting laser is irradiated to the defective portion of the solidified layer 83b where the powder material 5 is spread, and the powder material 5 is melted. When the irradiation of the melting laser is completed, the melted powder material 5 is naturally cooled and solidified together with the solidified layer 83b. In this way, the defective portion of the solidified layer 83b can be corrected. After the defective portion of the solidified layer 83b is corrected in step S9, steps S3 and S4 are performed to determine whether or not the defective portion is corrected.

  If the reflected light intensity is within the specified value in step S4, and if the defect occurrence rate is equal to or less than the specified value in step S7, it is determined whether the modeling stage 3 is below the predetermined stop position (step S10). The predetermined stop position is a position where the upper surface of the shaped product 8 is on the z-axis negative direction side of the upper surface of the main body 2.

  When the modeling stage 3 is higher than the predetermined stop position in step S10, the step of lowering the modeling stage 3 by one layer (step S11) is performed. Then, Steps S2 to 9 are performed to form the next solidified layer 83b, inspect the defective portion, and correct the defective portion. Steps S2 to 11 are repeated until the modeling stage 3 is at or below the predetermined stop position, and the modeling product 8 is manufactured.

  In the defect inspection method according to the present embodiment, the defect occurrence location is inspected each time the solidified layer 83b is formed. Therefore, a defect can be detected when the modeled object 83 is modeled. In addition, it is possible to correct a defect that occurs when the modeled object 83 is modeled.

  By the invention according to the present embodiment described above, it is possible to provide a defect inspection method capable of detecting a defect when forming a modeled object.

  The present invention is not limited to the above-mentioned embodiments, but can be modified as appropriate without departing from the spirit of the present invention.

1 Defect Inspection Device 2 Main Body 23 Modeling Space 24 Powder Supply Space 3 Modeling Stage 3a Vertical Moving Mechanism 4 Powder Supply Stage 4a Vertical Moving Mechanism 5 Powder Material 5b Powder Layer 6 Coater 7 Inspection Laser 71 Laser Oscillator 72 Mirror 73 Sensor 8 Modeling Product 83 Modeled object 83b Solidified layer

Claims (1)

The step of laminating a powder layer on the modeling stage and the step of solidifying a predetermined portion of the powder layer to form a solidified layer are repeated to inspect the molded article on the modeling stage for defects. A defect inspection method,
A step of scanning an inspection laser on the solidified layer,
A defect inspection method, wherein in the scanning step, the reflected light intensity of the inspection laser is recorded together with the scanning position of the inspection laser, the defect of the solidified layer is detected, and the position of the defect is specified.