JP6600211B2 - Electric dust collector - Google Patents

Description

  The present invention relates to an electric dust collector for collecting dust such as fumes generated from a processing machine such as an additive manufacturing apparatus for manufacturing a three-dimensional shaped object.

  In general, an additive manufacturing apparatus is used to manufacture a three-dimensional shaped object. In this additive manufacturing apparatus, in a processing chamber maintained in a predetermined inert atmosphere, a powder layer forming step for forming a powder layer, and a sintered layer forming step for forming a sintered layer by irradiating the powder layer with a laser And a cutting step of cutting the laminated sintered layer. Among these steps, in the sintered layer forming step, a laser emitted from laser irradiation means outside the processing chamber is irradiated to the powder layer in the processing chamber through the light transmission window of the processing chamber, and the powder layer is sintered or melted and solidified. The At this time, a smoke-like substance called a fume (for example, metal vapor) is generated from the laser irradiation site, and the fume rises and adheres to or burns into the light transmission window of the processing chamber. As a result, when the light transmission window becomes cloudy and the laser transmittance, refractive index, and the like are lowered, a desired solidified layer cannot be obtained, and the manufacture of the originally shaped object is hindered. In particular, when a metal powder layer is used as the powder layer, the strength of the layered object may be lowered due to reasons such as unstable sintering and high consolidation density.

  Therefore, in Patent Document 1, a pipe is connected to the ventilation path in the processing chamber of the additive manufacturing apparatus, and a dust collector such as a filter-type dust collector or a cyclone centrifugal dust collector is connected to the pipe. A technique has been proposed in which fumes generated in the processing chamber are collected and the inert gas such as nitrogen gas is cleaned.

JP 2010-47813 A

  However, as proposed in Patent Document 1 described above, in a layered manufacturing apparatus that requires long-time operation, when a filter-type dust collector is used, the filter is clogged with the usage time and the air volume is reduced. The fume collection performance is reduced. In addition, the cyclone centrifugal dust collector is not suitable for collecting those containing fine particles such as fume. Therefore, in the technique of the above-described Patent Document 1, it is not possible to sufficiently prevent the light transmissive window from being contaminated by the fume of the processing chamber generated from the laser irradiation location, so that the accuracy of laser processing cannot be maintained. There is a problem that the originally designed object cannot be manufactured.

  The present invention has been made to solve the above-described problems, and reliably collects dust such as fumes generated during laser processing in an inert gas environment such as nitrogen gas in a processing machine such as an additive manufacturing apparatus. It is an object of the present invention to provide a dust collecting device that can perform stable operation and collection performance for a long period of time.

In order to solve the above-described problems, a first electrostatic precipitator according to the present invention is an electrostatic precipitator for collecting dust such as fumes generated from a processing machine, and charges the dust by applying a high voltage. A charging unit that collects the dust charged by the charging unit, a fan that forcibly sends a dust-containing gas containing the dust to the charging unit and the dust collection unit, and the collection unit. When receiving a dust removing member for removing the dust trapped in the dust collecting part, a front Symbol machine dust removal permission signal output from the machine during the operation of, with respect to the charge unit is stopped the fan A control unit that removes the dust collected by the dust collecting unit by the dust removing member after stopping the application of a high voltage.

  According to the electric dust collector having this feature, dust collected in the dust collector during operation of the processing machine can be removed, so that stable dust collection operation for a long period of time can be performed and processing can be performed. Stable processing in the machine can be maintained.

In the second electric dust collector according to the present invention, the control unit, wherein the time of machine stop, after stopping the application of high voltage to the charging unit to stop the fan, capturing the dust collecting part The collected dust is removed by the dust removing member.

  According to the electrostatic precipitator having this feature, by removing the dust from the dust collector when the processing machine is stopped, dust does not accumulate in the dust collector at the start of processing of the next modeled object. A dust operation can be performed, and stable processing in the processing machine can be maintained.

In the third electric dust collector according to the present invention, the control unit, and wherein the operation time until it reaches a predetermined time, controls the application of high voltage to the fan and the charged portion so as not to stop To do.

  According to the electric dust collector having this feature, cleaning can be performed in a state where a certain amount of dust is accumulated in the dust collecting portion, so that dust accumulated in the dust collecting portion can be efficiently removed.

In the fourth electric dust collector according to the present invention, the control unit is configured during machine operation, only while receiving the dust removal permission signal output from the processing machine, the dust collection unit The dust collected in the container is removed by the dust removing member.

  According to the electrostatic precipitator having this feature, the cleaning can usually be completed within the time of the process in which dust is not generated, and if the output of the dust removal permission signal is stopped, even during the cleaning, Since the cleaning can be forcibly finished, the dust collecting operation does not affect the operation of the processing machine.

Further, in the fifth electric dust collector according to the present invention, the processing machine includes a powder layer forming step for forming a powder layer in the processing chamber, and a sintering for forming a sintered layer by irradiating the powder layer with a laser. A layered manufacturing apparatus that manufactures a three-dimensional shaped object by a layer forming step and a cutting step of cutting the laminated sintered layer, and the control unit removes the dust removal permission signal from the powder layer. It is output between the forming process and the cutting process.

  According to the electric dust collector having this feature, since the dust collecting part can be cleaned between the powder layer forming process and the cutting process in which dust is not generated from the processing machine, the dust collecting operation may be adversely affected. Absent.

Further, in the sixth electric dust collector according to the present invention, the control unit, the in machine operation, until the oxygen concentration of the processing chamber drops below a predetermined concentration, was the application of high voltage to the charge section Only the fan is operated.

  According to the electric dust collector having this feature, the processing chamber can be quickly brought to a predetermined oxygen concentration or less, and therefore the operation of the processing machine and the dust collecting operation can be performed efficiently.

Further, in the seventh electrostatic precipitator according to the present invention, the charging unit has a discharge electrode for charging the dust, and the control unit is configured to release the discharge electrode when an oxygen concentration in the processing chamber decreases to a predetermined concentration or less. It is controlled to apply a high voltage to the positive electrode.

  According to the electric dust collector having this feature, the generated dust can be stably charged and collected even in an inert atmosphere.

  Further, in the eighth electrostatic precipitator according to the present invention, the discharge electrode is a pointed needle electrode made of a JIS 60 alloy, has a diameter of 0.5 to 1.0 mm, and a discharge space distance of 13. The applied voltage is +6 to +8 kV at ˜15 mm.

  According to the electric dust collector having this feature, corona discharge can be stably generated even in an inert atmosphere. Further, by applying a relatively low voltage with respect to the discharge space distance, stable corona discharge with less abnormal discharge can be realized.

  In the ninth electrostatic precipitator according to the present invention, the dust collector includes a plurality of rotating electrode plates that are rotatable around a central axis, and the charging unit is interposed between the rotating electrode plates. The fixed electrode plate is characterized in that an adjustment member is provided on the fixed electrode plate so as to narrow a spatial distance from the rotating electrode plate.

  According to the electric dust collector provided with this feature, the electric field strength can be improved and the collection efficiency can be improved by narrowing the spatial distance by the adjusting member.

  According to the electrostatic precipitator according to the present invention, in a processing machine such as an additive manufacturing apparatus, dust such as fumes generated at the time of laser processing in an inert gas environment can be reliably collected and stable for a long period of time. Various excellent effects can be obtained, such as being able to maintain stable operation and collection performance.

It is a whole block diagram in the case of using the electric dust collector which concerns on embodiment of this invention for the system which removes the dust generated from a processing machine. It is sectional drawing which shows the process of manufacturing the three-dimensional shaped molded article with the processing machine in FIG. 1, (a) shows a powder layer formation process, (b) shows a sintered layer formation process, (c) is The cutting process is shown. It is a perspective view which sees through and shows the inside of the electrostatic precipitator which concerns on embodiment of this invention. It is a perspective view which shows the dust collector main body of the electric dust collector which concerns on embodiment of this invention. It is a perspective view which shows the inside of the dust collector main body of the electric dust collector which concerns on embodiment of this invention. It is a side view which shows the inside of the dust collector main body of an electric dust collector in embodiment of this invention. It is a top view which shows the principal part of the dust collector main body of the electric dust collector which concerns on embodiment of this invention. It is a top view which expands and shows the principal part of the dust collector main body of the electric dust collector which concerns on embodiment of this invention. It is a time chart which shows the effect | action of the electrostatic precipitator which concerns on embodiment of this invention. It is a whole block diagram which shows the modification in the case of using an electrostatic precipitator for embodiment of this invention for the system which removes the dust generated from a processing machine.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, for the sake of convenience, the front side in the direction perpendicular to the paper surface in FIG. 1 is the front side (front side), and the horizontal and vertical directions are based on the orientation in FIG.

  FIG. 1 is an overall configuration diagram in the case where an electric dust collector 2 according to an embodiment of the present invention is used in a system for removing dust generated from a processing machine 1. As shown in FIG. 1, the processing machine 1 and the electrostatic precipitator 2 are connected by an intake duct 3 and an exhaust duct 4 so as to form a circulation path. An inert gas supply source 5 is connected to the processing machine 1 through a pipe 6, and a supply valve 7 is connected to the processing machine 1 so that it can be opened and closed. A control unit 9 and an oximeter 10 are connected to the processing machine 1 via a control line 8, and the supply valve 7 and the oximeter 10 are connected to the control unit 9 via a control line 8. Further, an ozone removing device 11 may be provided in the middle of the exhaust duct 4 in the vicinity of the electric dust collector 2.

  As shown in FIG. 2, the processing machine 1 is a layered manufacturing apparatus that manufactures a three-dimensional modeled object, and has a processing chamber 12 with high airtightness. In the processing chamber 12, inert gas such as nitrogen is supplied from the inert gas supply source 5 through the pipe 6 in order to prevent material oxidation and dust explosion, and the atmosphere in the processing chamber 12 is It is kept airtight in an inactive state. The inside of the processing chamber 12 is maintained at a predetermined oxygen concentration by continuously supplying an inert gas while a three-dimensional shaped object is manufactured by the processing machine 1, and preferably 3%. Hereinafter, the oxygen concentration is more preferably maintained in the range of 0.5 to 3%.

  A window 13 having light transmittance is provided on the upper surface of the processing chamber 12. Inside the processing chamber 12, a modeling / processing table 14, a blade 15, and an end mill 16 are provided. A laser irradiation means 17 is disposed above the window 13 outside the processing chamber 12. ing.

  When manufacturing a three-dimensional shaped object in the processing machine 1 having such a configuration, first, as shown in FIG. 2 (a), in the processing chamber 12 held in an inactive state. A powder layer forming step (squeezing) for forming a powder layer is performed. In this powder layer forming process, the metal powder 18 is supplied onto the modeling / processing table 14 from a powder tank (not shown). The metal powder 18 is leveled by the blade 15 to form a first powder layer having a predetermined thickness (for example, 0.05 mm thickness). In addition, this powder layer formation process is performed once every several minutes (about 5 minutes).

  Next, as shown in FIG. 2B, a sintered layer forming step is performed in which the powder layer is irradiated with laser to form a sintered layer in the processing chamber 12 held in an inactive state. Is called. In this sintered layer forming step, the laser irradiation means 17 irradiates the portion of the first powder layer to be cured through the window 13 with the laser irradiation means 17. As a result, the metal powder 18 is sintered, and a first sintered layer 19 a is formed on the modeling / processing table 14.

  In this sintered layer forming step, dust-containing gas containing dust such as fume of iron-based metal powder is generated in the processing chamber 12. This dust-containing gas flows into the electrostatic precipitator 2 through the intake duct 3 as shown by arrows in FIGS. 1 and 2B. In the electric dust collector 2, the dust-containing gas is removed from the dust such as fume to become a clean gas, and then returned to the processing machine 1 through the exhaust duct 4. Thereafter, while a three-dimensional shaped object is manufactured in the processing machine 1, the same processing is repeated for the dust-containing gas. In addition, the effect | action in the electrostatic precipitator 2 is mentioned later.

  When the first sintered layer 19a is formed as described above, the modeling / processing table 14 is lowered, and the metal powder 18 is again supplied onto the modeling / processing table 14, and the above-described powder layer forming step Then, a sintered layer forming step is performed, and the second sintered layer 19b is formed in an integrated state with the first sintered layer 19a (see FIG. 2C). Thereafter, the powder layer forming step and the sintered layer forming step are repeatedly performed a predetermined number of times (for example, 10 times), and the next cutting step is performed when the sintered layer is formed to a predetermined thickness of several hundred μm (for example, 500 μm). Proceed to

  In the cutting process, as shown in FIG. 2C, cutting is performed on the integrally laminated sintered layer 19 in the processing chamber 12 held in an inactive state. In this step, the contour of the three-dimensional shaped object is cut with high speed and precision by the end mill 16, and finishing is performed. Note that the cutting is performed at a frequency of once every several hours to several tens of hours.

  Next, the electrostatic precipitator 2 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 3 to 8. Here, FIG. 3 is a perspective view showing the inside of the electric dust collector 2 in a transparent manner, FIG. 4 is a perspective view showing the dust collector body 20 of the electric dust collector 2, and FIG. 5 is a perspective view showing the inside of the dust collector body 20 of the electric dust collector 2. 6 is a side view showing the inside of the dust collector main body 20 of the electric dust collector 2, FIG. 7 is a plan view showing the main part of the dust collector main body 20 of the electric dust collector 2, and FIG. 8 shows the main part of the dust collector main body 20 of the electric dust collector 2. It is a top view which expands and shows.

The electric dust collector 2 includes a substantially rectangular parallelepiped dust collector body 20, a dust box 21 provided below the dust collector body 20, and a panel box 22 provided in front of the dust collector body 20.
A chamber box 26 is attached to the right side surface of the electrostatic precipitator 2, and an air inlet 27 is provided on the upper surface of the chamber box 26.

  The dust collector body 20 is detachably housed in a predetermined position inside the electric dust collector 2. The dust collector main body 20 includes an outer frame 23 that forms the contour of the dust collector main body 20. An opening 24 is formed on the right side surface of the outer frame 23, and guide plates 25 for guiding dust-containing gas from the air inlet 27 into the dust collector main body 20 are arranged above and below the opening 24. An opening 28 is formed on the upper surface of the outer frame 23, and an upper panel 29 is attached so as to close the opening 28. An exhaust port 30 is provided at the upper left end of the upper panel 29, and a fan 35 is disposed in the electric dust collector 2 below the exhaust port 30. In addition, on the front outer side of the front plate 31 of the outer frame 23 and the rear outer side of the rear plate 32, insulator mounting plates 34 are respectively attached in parallel to the front plate 31 and the rear plate 32 via columnar insulators 33. ing. Since this insulator has electrical insulation, the insulator mounting plate 34 and the front side plate 31 and the rear side plate 32 are electrically insulated.

  The dust box 21 has an open front surface, and an open / close door 35 is airtightly provided on the front surface. The panel box 22 houses an electrical component (not shown) inside, and is attached to the front surface of an open / close door 37 that is airtightly provided on the front outer side of the outer frame 23. The electrical component is connected to the controller 9 via a control line 8 (see FIG. 1).

  Inside the outer frame 23, a charged dust collecting portion 40 in which a charging portion and a dust collecting portion are integrated is provided. The charged dust collecting unit 40 is interposed between a plurality of rotating electrode plates 41 (six in this embodiment) that are arranged side by side at equal intervals in the front-rear direction, and between each rotating electrode plate 41. Fixed electrode plate 42 constituting a plurality of (five in the present embodiment) charging portions to be mounted, and dust removal arranged obliquely downward to the left from the center of rotating electrode plate 41 and fixed electrode plate 42 And a scraper 43 as a member. In the present embodiment, since the capacity in the processing chamber 12 is relatively small and the amount of processing air required for the electrostatic precipitator 2 is small, the charged dust collecting unit 40 is a two-stage type (the charging unit and the dust collecting unit are It is possible to use a compact one-stage system (a configuration in which the charging unit and the dust collecting unit are integrated) instead of the separated configuration.

  The rotating electrode plate 41 has a disk shape, is grounded via the outer frame 23, and its center is fixed to the central shaft 44. The central shaft 44 is horizontally supported between the central portion of the front plate 31 and the central portion of the rear plate 32, and a joint 61 provided at the front end portion of the central shaft 44 is coaxial with the central shaft 44. It is connected with the geared motor (illustration omitted) through the coupling which is not shown in figure. A reduction mechanism (not shown) is provided inside the geared motor, and the rotational driving force from the geared motor is decelerated by the reduction mechanism and transmitted to the central shaft 44. The central shaft 44 and the rotating electrode plate 41 is configured to rotate integrally. The rotation speed of the central shaft 44 and the rotating electrode plate 41 is, for example, about 2 rotations per minute, and the rotation direction is clockwise in front view as shown in FIG.

  A plurality of support rods 45 having both ends fixed to the front side plate 31 and the rear side plate 32 with bolts are provided in the front-rear direction on the upper left and right sides and the lower left and right sides of the rotating electrode plate 41. A plurality (five in this embodiment) of guide grooves 46 are formed at equal intervals on the peripheral surface of the support rod 45, and the outer edge of the rotary electrode plate 41 enters the guide grooves 46 to rotate. The electrode plate 41 is guided by a support rod 45.

  The fixed electrode plate 42 has a flat plate shape and is arranged at the center of the installation interval of the rotating electrode plates 41. Shafts 47 extend in the front-rear direction at the four corners of the fixed electrode plate 42, and the fixed electrode plates 42 are fixed at regular intervals via conductive spacers 48 provided on the shaft 47. Both front and rear ends of the shaft 47 pass through circular relief holes 49 drilled in the four corners of the front side plate 31 and the rear side plate 32 and are fixed to the four corners of the insulator mounting plate 34 with bolts. As a result, the fixed electrode plate 42 and the rotating electrode plate 41 are electrically insulated, and when power is supplied to the insulator mounting plate 34 from voltage supply means (not shown), the fixed electrode plate 42 is positively connected to the fixed electrode plate 42 via the shaft 47. A high voltage is applied.

  The fixed electrode plate 42 is formed with a substantially rectangular opening 50 that is long in the vertical direction on the right side of the center in front view. Thereby, the right edge 51 of the fixed electrode plate 42 is formed in a vertically long strip shape. A large number of needle-like upstream discharge electrodes 52 are supported at equal intervals in the vertical direction on the right edge 51 of the fixed electrode plate 42 by means such as welding or caulking. The upstream discharge electrode 52 is inclined slightly upward (for example, about 9 ° from the horizontal plane) to the upper right or lower right, and both left and right ends are open to the opening 50 or the right space. Similarly, on the left side of the opening 50 of the fixed electrode plate 42, a large number of needle-like downstream discharge electrodes 53 are supported in a cantilever manner at equal intervals in the vertical direction by means such as welding or caulking. ing. The downstream discharge electrode 53 is inclined slightly above the right side (for example, about 9 ° from the horizontal plane), and the right end is opened to the opening 50. As a result, when a positive high voltage is applied from the voltage supply means to the fixed electrode plate 42, the discharge electrodes 52 and 53, in particular, the tip portions thereof act as charged portions so that the discharge can be performed efficiently. .

  The upstream discharge electrode 52 and the downstream discharge electrode 53 are made of a titanium alloy called 64 titanium, specifically, a JIS 60 type alloy (6% Al + 4% V + 90% Ti) and a diameter of 0.8 mm. have. The left and right ends of the upstream discharge electrode 52 and the right end of the downstream discharge electrode 53 each have a pointed cone shape (for example, an opening angle of 15 °), and the tip diameter of the pointed cone shape is 0.05 mm. The cone portion may be polished (rubber polishing or the like). Eighteen upstream discharge electrodes 52 are provided per fixed electrode plate 42, and a total of five fixed electrode plates 42 are provided. Further, 16 downstream discharge electrodes 53 are provided for each fixed electrode plate 42, and a total of 80 fixed electrode plates 42 are provided. The diameters of the discharge electrodes 52 and 53 are not limited to 0.8 mm described above, but are preferably in the range of 0.5 to 1.0 mm.

  Between the discharge electrodes 52 and 53 and the rotating electrode plate 41, a voltage lower than normal (10 to 12 KV), preferably +6 to +8 KV, more preferably +6 to +7 KV is positively charged. Applied. In general, in the case of a negative charge system, discharge is performed through oxygen ions, but in an inert atmosphere such as in the processing chamber 12, oxygen that mediates discharge is reduced, so that only the discharge of electrons occurs, and current is discharged. Increases rapidly, and a high voltage cannot be applied. On the other hand, in the case of the positive charge method, ions are directly emitted from the tips of the discharge electrodes 52 and 53, so that they are not easily influenced by the oxygen concentration, and even in an inert atmosphere such as in the processing chamber 12, It is easy to obtain similar characteristics. Therefore, in this embodiment, a positive charge method is adopted.

  7 and 8, the left side portion of the fixed electrode plate 42 is flat on both sides of the fixed electrode plate 42 in order to reduce the spatial distance (discharge gap) with the rotary electrode plate 41. The adjusting member 54 is fixed by caulking or the like. By fixing the adjusting member 54 on both surfaces of the fixed electrode plate 42, the spatial distance between the rotating electrode plate 41 and the fixed electrode plate 42 is reduced by the plate thickness of the adjusting member 54 (the gap becomes narrow), and the electric field strength is increased. Therefore, dirt (dust) can be efficiently collected on the surface of the rotary electrode plate 41.

  In the present embodiment, the thickness of the adjustment member 54 is 2 mm, and as shown in FIG. 8, the discharge gap G1 between the discharge electrodes 52, 53 and the rotary electrode plate 41 is 14.5 mm, and the adjustment member 54 and the rotary electrode plate The discharge gaps G2 and G3 with respect to 41 are 11.5 mm and 12.5 mm, respectively. The discharge gaps G2 and G3 are different because the discharge electrodes 52 and 53 are arranged at the center between the rotary electrode plates 41 and the plate thickness of the adjustment member 54 is the same. The discharge gaps G2 and G3 may be made the same by appropriately adjusting. Moreover, although the discharge gap G1 is not limited to 14.5 mm mentioned above, it is preferable to set in the range of 13-15 mm.

  The fixed electrode plate 42 is formed with a notch 55 in the radial direction from the lower left outer peripheral portion toward the central axis 44. The notch 55 is formed in an inverted U shape so as not to interfere with the scraper 43 and the central shaft 44.

  The scraper 43 is made of a metal plate and is linearly formed along the notch 55. The upper end of the scraper 43 is wound around and fixed to the outer periphery of a bearing 56 attached to the central shaft 44, and the lower end is fixed to the front and rear side plates 31 and 32. A plurality (six in this embodiment) of slit holes 62 are formed in the scraper 43, and the rotary electrode plate 41 is loosely inserted in each of the slit holes 62.

  The scraper 43 is disposed at a position where the peripheral end surface of the slit hole 62 is as close to the surface of the rotary electrode plate 41 as possible so that the rotation operation of the rotary electrode plate 41 is not hindered. Thereby, the rotating electrode plate 41 rotates in the slit hole 62 in the clockwise direction, so that dirt (dust) adhering to the surface of the rotating electrode plate 41 can be scraped off by the scraper 43. For example, a rubber scraping member may be attached to the peripheral end surface of the slit hole 62 to scrape dirt (dust) attached to the surface of the rotating electrode plate 41.

  In addition, a plurality of rectangular openings 57 are formed between the slit holes 62, so that even if dirt (dust) accumulates to form a large mass, the openings 57 are arranged below the openings 57. The dust box 21 falls. The scraper 43 described above is formed in a straight line, but may be formed so that the central portion protrudes upward so that dirt (dust) can be more easily dropped.

  Next, the action of the electric dust collector 2 when collecting dust in the dust-containing gas generated in the processing machine 1 will be described in detail with reference to FIG. 9 in addition to FIGS. Here, FIG. 9 is a time chart showing the operation of the electrostatic precipitator 2.

  When the operation of the processing machine 1 is started and a fan operation signal is output (turned on) from the control unit 9, the fan 35 of the electrostatic precipitator 2 is activated and is operating in the display unit 36 (see FIG. 1) of the electrical equipment unit. The lamp is turned on. On the other hand, in the processing machine 1, the supply valve 7 is opened, and the inert gas is supplied from the inert gas supply source 5 through the pipe 6 into the processing chamber 12. When the oxygen concentration value in the processing chamber 12 measured by the oximeter 10 becomes a predetermined concentration (for example, 3%) or less, the processing machine 1 starts processing, and the control unit 9 outputs a high voltage application signal. (ON) and transmitted to the electric dust collector 2 side.

  In the electrostatic precipitator 2, a positive high voltage is applied to the discharge electrodes 52 and 53 from the voltage supply means based on the high voltage application signal, and the high voltage lamp is turned on in the display unit 36 of the electrical equipment unit. As a result, corona discharge occurs at the discharge electrodes 52 and 53.

  At this time, the dust-containing gas generated during the processing of the three-dimensional shaped object in the processing chamber 12 passes through the intake duct 27 and the intake port 3 by the suction action of the fan 35 in the horizontal direction inside the electric dust collector 2. And passes between the rotating electrode plate 41 and the fixed electrode plate 42. Dust in the dust-containing gas is charged by corona discharge from the discharge electrodes 52 and 53 while passing between the rotary electrode plate 41 and the fixed electrode plate 42, and the charged dust is downstream of the discharge electrodes 52 and 53. Adsorbed and collected by a plurality of rotating electrode plates 41 located on the side.

  While the processing machine 1 is in operation, while the powder layer forming step (squeezing) or the cutting step is performed in the processing chamber 12, the control unit 9 generates a dust removal permission signal. The first cleaning permission signal is output (turned on). At this time, the laser irradiation means 17 is interlock controlled by the controller 9 so that the first cleaning permission signal is not output while the sintered layer forming step is being performed.

  When the electrostatic precipitator 2 receives the first cleaning permission signal after a predetermined time H has elapsed from the start of operation of the fan 35 (variable range: 300 to 240 minutes), the electrostatic precipitator 2 stops the fan 35 and The voltage application is stopped and the first cleaning operation is performed for a predetermined time (variable range: 15 to 120 seconds). The control unit 9 controls the electric dust collector 2 so as not to stop the application of a high voltage to the fan and the charging unit until the operation time of the fan 35 reaches a predetermined time.

  During the first cleaning operation, the rotary electrode plate 41 is rotated at a low speed clockwise (two rotations per minute) in front view. As a result, the dust collected and deposited on each rotating electrode plate 41 is scraped off in contact with the scraper 43 and falls into the dust box 21 as it is due to its own weight. Thereafter, while the electrostatic precipitator 2 continues to operate, the same operation is repeated, and the first cleaning operation after the second time is performed similarly to the first time.

  When the first cleaning permission signal from the control unit 9 is canceled during the first cleaning operation, the first cleaning operation is stopped, the fan 35 is operated, and the charging unit is turned on. Application of a voltage is started and the operation of the electrostatic precipitator 2 is resumed. Further, in the above description, the first cleaning operation is started after a predetermined time H has elapsed from the start of the operation of the fan 35, but the start of the predetermined time H is started to apply a high voltage to the discharge electrodes 52 and 53. It may be a point in time. The predetermined time H may be a cumulative operation time instead of a continuous operation time.

  On the other hand, as described above, the air that has been cleaned by removing dust while passing through the inside of the electrostatic precipitator 2 changes the direction of the airflow upward, passes through the exhaust port 4 and the exhaust duct 30, and is processed by the processing machine. Returned to 1.

  Thereafter, when the processing machine 1 is stopped and the fan operation signal and the high voltage application signal are not output from the control unit 9 (turned off), the fan 35 of the electrostatic precipitator 2 is stopped and the discharge electrodes 52 and 53 are high. The application of voltage is stopped, and the operating lamp changes to blinking on the display section 36 of the electrical equipment section. Thereby, the electrostatic precipitator 2 stops the fan 35 and stops the application of the high voltage to the charging unit, and performs the second cleaning operation for a predetermined time (variable range: 2 to 10 minutes). The high voltage lamp blinks on the display unit 36 of the electrical equipment until there is no remaining voltage on the discharge electrodes 52 and 53.

  During the second cleaning operation, the rotating electrode plate 41 is rotated at a low speed clockwise (two rotations per minute) when viewed from the front. As a result, dust collected and accumulated on each rotating electrode plate 41 is removed from the scraper. 43 is scraped off and falls into the dust box 21 by its own weight. When the second cleaning operation is completed, the operating lamp of the display unit 36 of the electrical unit disappears. When the operation signal of the fan 35 from the control unit 9 is turned on during the second cleaning operation, the second cleaning operation is stopped and the operation of the fan 35 is resumed.

  In the electrostatic precipitator 2 described above, the operation time of the first cleaning is set to 15 seconds, and the operation time of the second cleaning is set to 2 minutes longer than the operation time of the first cleaning. In this case, assuming that the rotation speed of the rotating electrode plate 41 is 2 RPM (2 rotations per minute), in the first cleaning, half of the rotating electrode plate 41 can be cleaned by one operation. Further, in the case of the second cleaning, four rotations of the rotary electrode plate 41 can be cleaned by one operation, so that dust that has reliably accumulated on the rotary electrode plate 41 when the processing machine 1 is stopped. Can be removed. The first cleaning operation is to perform cleaning between operations so as not to hinder the modeling work in the processing machine 1, and the time of the powder layer forming step (squeezing) is 20 seconds. Therefore, the operation time of the first cleaning is set to 15 seconds, but the operation time can be changed within the time of the powder layer forming step (squeezing).

  As described above, according to the electrostatic precipitator 2 according to the above-described embodiment of the present invention, the dust-containing gas generated in the processing chamber 12 can be stably cleaned for a long period and returned to the processing chamber 12. It is possible to prevent the window 13 of the processing chamber 12 from being contaminated with dust such as fume. Therefore, the accuracy of laser processing in the processing machine 1 can be stably maintained high. Moreover, since the contamination of the inert gas in the processing chamber 12 can be prevented, it is not necessary to replace the inert gas, and the operating cost can be reduced.

  Further, since a small amount of oxygen remains in the processing chamber 12, ozone is generated in the processing chamber 12 due to discharge in the charged dust collection unit 40, and ozone is generated when the door of the processing chamber 12 is opened by taking out a modeled object or the like. Odor may be generated, but by arranging the ozone removing device 11 on the downstream side of the electric dust collector 2, ozone can be removed (decomposed and collected), and generation of ozone odor can be prevented. .

  In general, the amount of ozone generated from the charged part of the electrostatic precipitator 2 may increase depending on the humidity, abnormal discharge, etc., and the performance of the ozone removing device 11 using, for example, activated carbon or a catalyst is also considered. Because it depends, it is difficult to decompose (collect) ozone 100%. Therefore, at the end of the second cleaning operation, only the fan 35 is operated for a predetermined time set in advance (high voltage application is kept off), and the ozone removal device 11 removes residual ozone ( A circulation mode (decomposed and collected) (indicated by a broken line in FIG. 9) may be provided. In this case, the door is locked by the control unit 9 so that the door of the processing chamber 12 of the processing machine 1 does not open during the circulation mode operation.

  In addition, as shown in FIG. 10, after arrange | positioning the three-way valve 60 in the downstream of the electrostatic precipitator 2, and branching a flow path into two, the ozone removal apparatus 11a or 11b is arrange | positioned in each flow path. Also good. In this case, each of the ozone removing devices 11a and 11b is provided with a differential pressure gauge 58a and 58b indicating a clogged state, and each of the ozone removing devices 11a and 11b is provided with a check for preventing a backflow in the flow path on the downstream side. Valves 59a and 59b are provided.

  By adopting such a configuration, for example, even when one ozone removal device 11a becomes clogged with the passage of usage time and needs to be replaced, the three-way valve 57 is switched to change the flow path. Thus, the other ozone removing device 11b can be used. In other words, even if the processing machine 1 is processing a modeled object, the clogged ozone removing device 11a can be replaced without stopping or interrupting the modeled object. Can be done well.

  In addition, since the above description of the embodiment of the present invention describes a preferred embodiment of the electric dust collector according to the present invention, there may be various technically preferable limitations. The technical scope of the present invention is not limited to these embodiments unless specifically described to limit the present invention. That is, the above-described components in the embodiment of the present invention can be appropriately replaced with existing components and the like, and various variations including combinations with other existing components are possible. The description of the embodiment of the present invention described above does not limit the contents of the invention described in the claims.

  The technology of the present invention is expected to be used in an electric dust collector that collects dust such as fumes generated from a processing machine such as a layered manufacturing apparatus that manufactures a three-dimensional shaped object.

1 Processing Machine 2 Electric Dust Collector 12 Processing Room 35 Fan 41 Rotating Electrode Plate (Dust Collector)
42 Fixed electrode plate (Charging part)
43 Scraper (dust removal member)
44 Central axis 52 Upstream discharge electrode (charged part)
53 Downstream discharge electrode (charge part)

Claims (9)

An electric dust collector for collecting dust such as fumes generated from a processing machine,
A charging unit that charges the dust by applying a high voltage;
A dust collecting unit for collecting the dust charged by the charging unit;
A fan for forcibly delivering a dust-containing gas containing the dust to the charging unit and the dust collecting unit;
A dust removing member for removing the dust collected in the dust collecting portion ;
When a dust removal permission signal output from the processing machine is received during operation of the processing machine, the fan is stopped and the application of a high voltage to the charging unit is stopped, and then collected in the dust collection unit A control unit for removing the dust by the dust removing member ;
Electrostatic precipitator, characterized in that it comprises a. When the processing machine is stopped , the control unit stops the fan and stops application of a high voltage to the charging unit, and then removes the dust collected by the dust collection unit by the dust removing member. The electrostatic precipitator according to claim 1. The electrostatic precipitator according to claim 1 or 2, wherein the control unit controls the application of a high voltage to the fan and the charging unit so as not to stop until an operation time reaches a predetermined time. During the operation of the processing machine , the control unit causes the dust removal member to collect the dust collected by the dust collection unit only while receiving a dust removal permission signal output from the processing machine. The electrostatic precipitator according to any one of claims 1 to 3, wherein the electrostatic precipitator is removed. In the processing chamber, the processing machine includes a powder layer forming step for forming a powder layer, a sintered layer forming step for forming a sintered layer by irradiating the powder layer with a laser, and cutting the stacked sintered layers. It is an additive manufacturing apparatus that manufactures a three-dimensional shaped object by a cutting process to be processed,
The electric dust collector according to any one of claims 1 to 4, wherein the control unit outputs the dust removal permission signal between the powder layer forming step and the cutting step. The control unit operates only the fan without applying a high voltage to the charging unit until the oxygen concentration in the processing chamber decreases to a predetermined concentration or less during operation of the processing machine. The electric dust collector according to claim 5. The charging unit includes a discharge electrode that charges the dust, and the control unit controls the high voltage of the positive electrode to be applied to the discharge electrode when the oxygen concentration in the processing chamber decreases to a predetermined concentration or less. The electric dust collector according to claim 5 or 6, characterized by the above.   The discharge electrode is a pointed needle electrode made of JIS 60 type alloy, has a diameter of 0.5 to 1.0 mm, a discharge space distance of 13 to 15 mm, and an applied voltage of +6 to +8 kV. The electric dust collector according to claim 7. The dust collecting unit includes a plurality of rotating electrode plates rotatable around a central axis, and the charging unit includes a plurality of fixed electrode plates interposed between the rotating electrode plates, The electric dust collector according to any one of claims 1 to 8, wherein an adjustment member is provided so as to narrow a spatial distance from the rotating electrode plate.

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