This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2021-213266, filed on Dec. 27, 2021, in the Japan Patent Office, the entire disclosure of which is hereby incorporated by reference herein.
The present disclosure relates to a three-dimensional object fabrication method, and a three-dimensional object fabrication system.
Examples of known methods for fabricating a fabricated object that is an aggregated body of a plurality of fabrication layers, include a Selective Laser Sintering (SLS) method in which a laser beam is selectively emitted, an Electron Beam Melting (EBM) method in which an electron beam is emitted, and a Binder Jetting (BJ) method in which a binder (fabrication liquid) is applied.
A three-dimensional object fabrication method of the present disclosure includes forming a fabrication layer including a fabrication material, applying a fabrication liquid to the fabrication layer, flattening the fabrication layer, monitoring a scattering condition of the fabrication material in the forming and the flattening, and adjusting at least one of the forming and the flattening, based on a monitoring result of the scattering condition in the monitoring.
A more complete appreciation of embodiments of the present disclosure and many of the attendant advantages and features thereof can be readily obtained and understood from the following detailed description with reference to the accompanying drawings, wherein:
The accompanying drawings are intended to depict embodiments of the present disclosure and should not be interpreted to limit the scope thereof. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. Also, identical or similar reference numerals designate identical or similar components throughout the several views.
In describing embodiments illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the disclosure of this specification is not intended to be limited to the specific terminology so selected and it is to be understood that each specific element includes all technical equivalents that have a similar function, operate in a similar manner, and achieve a similar result.
Referring now to the drawings, embodiments of the present disclosure are described below. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
In known methods described above, a fabrication material scattered onto the fabrication layer freely falls. If a head (an example of a fabrication liquid application unit) is driven while the fabrication material is scattered, the fabrication material scatters over a wider area, which may cause a deterioration of the accuracy of a sensor, or a malfunction when the fabrication material enters into a gap of a part such as a motor. In particular, if the fabrication material sticks to a discharge port of the head, the fabrication liquid may not be discharged properly or the fabrication material may take the shape of an icicle, so that there is an influence on the quality of the fabricated object.
According to the present disclosure, an effect is achieved by which it is possible to reduce the scattering amount of a fabrication material, and prevent a case where a fabrication liquid is not discharged properly or the fabrication material takes the shape of an icicle, which influences the quality of a three-dimensional fabricated object that is a finished product.
A three-dimensional object fabrication method, a three-dimensional object fabrication apparatus, and a three-dimensional object fabrication system according to embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
The fabrication step (S1) is a step of forming a fabrication layer including a fabrication material. Specifically, the fabrication step (S1) includes moving a supply layer in a Z (height) direction (upward movement of the supply layer), supplying a fabrication material such as a powder to the supply layer by using a hopper, and collecting a residual material in an excess powder receiver. Here, the supply layer is a layer for the purpose of supplying a material. The excess powder receiver is a layer for collecting excess powder (residual material) remaining from recoating of the supply layer and the fabrication layer. The fabrication layer is a layer in which a thin layer of the material is formed and solidified by using a fabrication liquid.
The fabrication step (S1) further includes drive control including moving the fabrication layer in the Z (height) direction (downward movement of the fabrication layer), moving the fabrication liquid application unit (for example, a head), and moving a flattening unit (for example, a recoater). Here, the fabrication liquid application unit discharges (applies), to the fabrication layer, the fabrication liquid for solidifying the fabrication layer. The flattening unit includes a roller and the like, and flattens the supply layer and the fabrication layer.
The fabrication liquid application step (S2) is a step of applying a fabrication liquid to the fabrication layer from the fabrication liquid application unit. Specifically, the fabrication liquid application step (S2) includes replenishing the fabrication liquid from a fabrication liquid tank to the fabrication liquid application unit, discharging the fabrication liquid from the fabrication liquid application unit, and controlling a discharge amount and a timing of discharging the fabrication liquid from the fabrication liquid application unit.
The flattening step (S3) is a step of flattening the fabrication layer by the flattening unit. Specifically, in the flattening step (S3), when flattening the fabrication layer by the flattening unit, the rotation of the flattening unit (recoat roller) and the drive of the flattening unit are controlled.
The monitoring step (S4) is a step of monitoring a scattering condition of the fabrication material in the fabrication step (S1) and the flattening step (S3). Specifically, in the monitoring step (S4), a camera or the like (an example of a monitoring unit) is used to monitor the scattering condition (a scattering level) of a material such as a powder.
The adjustment step (S5) is a step of adjusting at least one of the fabrication step (S1) and the flattening step (S3) by an adjustment unit (for example, a processor such as a Central Processing Unit (CPU)) provided in the three-dimensional object fabrication system. Thus, the scattering condition of the fabrication material in the vicinity of a fabrication liquid application unit 105 and a source of the scattering of the fabrication material are monitored, the falling speed of the fabrication material is controlled, the source is controlled considering the characteristics of the size and the weight of the fabrication material, and the like. Therefore, it is possible to reduce the scattering amount of the fabrication material, and prevent a case where the fabrication liquid is not discharged properly or the fabrication material takes the shape of an icicle, which influences the quality of a three-dimensional fabricated object that is a finished product.
Specifically, in the adjustment step (S5), at least one of a movement speed of the fabrication liquid application unit 105 in the fabrication step (S1), a flattening speed of the flattening step (S3) (for example, a movement speed of the flattening unit), and a rotation speed of the flattening unit (the roller) in the flattening step (S3) is changed, based on a monitoring result of the scattering condition of the fabrication material. For example, in the adjustment step (S5), at least one of the movement speed of the fabrication liquid application unit 105 in the fabrication step (S1), the flattening speed in the flattening step (S3), and the rotation speed of the flattening unit (the roller) in the flattening step (S3) may be changed, based on the falling speed of the fabrication material (an example of the scattering condition of the fabrication material).
The preliminary adjustment step (S6) is a step of adjusting at least one of the fabrication step (S1) and the flattening step (S3) by a preliminary adjustment unit (for example, a processor such as a CPU) included in the three-dimensional object fabrication system, before fabricating the fabricated object that is an aggregated body of a plurality of fabrication layers. Specifically, in the preliminary adjustment step (S6), the flattening step (S3) or the fabrication step (S1) is monitored and material parameters including at least a type, a particle diameter, and density are calculated and stored. According to these material parameters, preliminary adjustment can be performed to decrease scattering. In the preliminary adjustment step (S6), the fabrication step (S1) is monitored and fabrication liquid parameters including at least a type and a droplet size are calculated and stored. According to these fabrication liquid parameters, preliminary adjustment can be performed to decrease scattering. In this case, in the adjustment step (S5), at least one of the fabrication step (S1) and the flattening step (S3) is adjusted, based on the material parameters and the fabrication liquid parameters.
In the fabrication step, first, the fabrication material is supplied (provided) from a hopper 102 to the supply layer 101. In the provision of the fabrication material to the supply layer 101, the fabrication material may be supplied to the supply layer 101 in advance or the fabrication material in the supply layer 101 may be replenished via the hopper 102.
The flattening unit 106 (recoat roller) is present at one end of the supply layer 101 (an end opposite to an end on the side of the fabrication layer 104), and recoats the supply layer 101, the fabrication layer 104, and the excess powder receiver 103. In the three-dimensional object fabrication system, the fabrication liquid application unit 105 that applies the fabrication liquid is present over the fabrication layer 104. The three-dimensional object fabrication system performs drive control of the flattening unit 106 and the fabrication liquid application unit 105 so that the flattening unit 106 and the fabrication liquid application unit 105 can operate efficiently.
Next, in the flattening step, excess fabrication material (residual material, excess powder) in the fabrication layer 104 is dropped into the excess powder receiver 103 (step S303). In the flattening step, steps S301 to S303 are repeated until a predetermined surface is formed on the fabrication layer 104.
Specifically, in the monitoring step, a scattering condition of the fabrication material (for example, a scattering level, which is the degree of scattering of the fabrication material) is monitored at operation points indicated by reference signs a, b, and c. In the monitoring step, as illustrated in
More specifically, in the monitoring step, an image is acquired, as a spatial image, in an area from the entire fabrication layer 104 to a drive region of the fabrication liquid application unit 105 that applies the fabrication liquid, and the scattering condition is monitored based on the image. The spatial image is acquired continuously at predetermined intervals or in each step. Here, the spatial image is an image in an area from the entire fabrication layer 104 to the drive region of the fabrication liquid application unit 105. In other words, the spatial image is an image including the entire region of the fabrication layer 104, the drive region of the fabrication liquid application unit 105, and a space region therebetween. Here, the steps include the fabrication step, the fabrication liquid application step, and the flattening step. In the monitoring step, the scattering condition of the fabrication material is monitored, based on the spatial image. The drive region of the fabrication liquid application unit 105 includes a scheduled passage region of the fabrication liquid application unit 105 with respect to a traveling direction of the fabrication liquid application unit 105 in the fabrication step.
The time required for eliminating the scattering of the fabrication material varies according to differences in the type of the fabrication material used to fabricate the fabricated object that is an aggregated body of a plurality of the fabrication layers 104. Therefore, in the monitoring step, a scattering monitoring timing is set by using the type, the particle diameter, the density, and the like of the fabrication material as material parameters (step S601). Here, the scattering monitoring timing is a timing for monitoring the scattering of the material in the fabrication step and the flattening step.
Next, in the monitoring step, the camera 107 monitors the scattering condition of the material at the scattering monitoring timing (step S602). In the present embodiment, in the monitoring step, as illustrated in
Next, in the monitoring step, it is determined whether the degree of scattering (scattering condition) of the monitored material is equal to or less than a predetermined level (step S603). Here, the predetermined level is a degree of scattering of the material set in advance, and is a threshold value of a scattering condition determining a stop of the scattering of the material. If the scattering condition is higher than the predetermined level (step S603: No), the monitoring step returns to step S601 and the scattering of the material is monitored again.
On the other hand, if the scattering condition is equal to or less than the predetermined level (step S603: Yes), the monitoring step proceeds to the next control action (step S604).
For example, as illustrated in
For example, if the scattering level of the fabrication material is higher than the predetermined level and the scattering level is a scattering level: 4, which is lower than the scattering level: 5, the three-dimensional object fabrication system determines that the scattering level of the fabrication material (the monitoring result of the scattering of the fabrication material) increases and decreases within a predetermined range or above, as indicated in
If the scattering level of the fabrication material is a predetermined level, that is, a scattering level: 3, the three-dimensional object fabrication system determines, as indicated in
If the scattering level of the fabrication material is lower than the predetermined level and the scattering level is a scattering level: 2, which is higher than a scattering level: 1, the three-dimensional object fabrication system determines that the scattering level of the fabrication material (the monitoring result of the scattering of the fabrication material) increases and decreases within a predetermined range or below, as indicated in
If the scattering level of the fabrication material is the minimum scattering level: 1, the three-dimensional object fabrication system determines that the scattering level of the fabrication material (the monitoring result of the scattering of the material) is a low level, as indicated in
In the present embodiment, the three-dimensional object fabrication system sets the initial value of the scattering monitoring timing, based on material parameters such as the type, the particle diameter, and the density of the fabrication material. After that, the three-dimensional object fabrication system updates the scattering monitoring timing, based on monitoring results of the scattering level in each of the fabrication step and the flattening step.
As illustrated in
Specifically, the three-dimensional object fabrication system first sets a combination of the movement speed, the rotation speed, and the like of the flattening unit 106 (step S1601). Next, the three-dimensional object fabrication system uses the flattening unit 106 to recoat the supply layer 101, the fabrication layer 104, and the excess powder receiver 103 (step S1602). Further, the three-dimensional object fabrication system uses the camera 107 to monitor the scattering condition of the fabrication material (step S1603).
Next, the three-dimensional object fabrication system determines whether the scattering condition of the fabrication material is optimal (step S1604). For example, if the scattering condition of the fabrication material is at a predetermined level, the three-dimensional object fabrication system determines that the scattering condition of the fabrication material is optimal. If the scattering condition of the fabrication material is optimal (step S1604: Yes), the three-dimensional object fabrication system stores the material parameters most recently set (step S1605).
Next, the three-dimensional object fabrication system determines whether the fabrication is completed for all combinations of material parameters (step S1606). If the fabrication is completed for all combinations of material parameters (step S1606: Yes), the three-dimensional object fabrication system stops setting combinations of material parameters.
On the other hand, if the scattering condition of the fabrication material is not optimal (step S1604: No) and if the fabrication is not completed for all combinations of material parameters (step S1606: No), the three-dimensional object fabrication system changes the combination of material parameters (step S1607) to repeat the processing illustrated in steps S1602 to S1606.
If there is a difference in at least one or more of the fabrication liquid parameters including the type and the droplet size of the fabrication liquid, the scattering mode of the fabrication material during the fabrication step of the fabricated object differs. Therefore, in the three-dimensional object fabrication system according to the present embodiment, as illustrated in
Specifically, the three-dimensional object fabrication system first sets a combination of the type and the droplet size of the fabrication liquid (step S1901). Next, the three-dimensional object fabrication system discharges the fabrication liquid from the fabrication liquid application unit 105 (step S1902). At that time, the three-dimensional object fabrication system uses the camera 107 to monitor the scattering condition of the fabrication material within the drive region of the fabrication liquid application unit 105 (step S1903).
Next, the three-dimensional object fabrication system determines whether the scattering condition of the fabrication material is optimal (step S1904). For example, if the scattering condition of the fabrication material is at a predetermined level, the three-dimensional object fabrication system determines that the scattering condition of the fabrication material is optimal. If the scattering condition of the fabrication material is optimal (step S1904: Yes), the three-dimensional object fabrication system sets and stores, as the optimal parameter combination, a combination of fabrication liquid parameters most recently set (step S1905).
Next, the three-dimensional object fabrication system determines whether the determination of whether the scattering condition is optimal is completed for all combinations of fabrication liquid parameters (step S1906). If it is determined for all combinations of fabrication liquid parameters whether the scattering condition is optimal (step S1906: Yes), the three-dimensional object fabrication system stops setting fabrication liquid parameters.
On the other hand, if the scattering condition of the fabrication material is not optimal (step S1904: No) and if the determination of whether the scattering condition is optimal is not completed for all combinations of fabrication liquid parameters (step S1906: No), the three-dimensional object fabrication system changes the combination of fabrication liquid parameters (step S1907) to repeat the processing illustrated in steps S1902 to S1906.
According to the three-dimensional object fabrication system in the present embodiment, the scattering condition of the fabrication material in the vicinity of the fabrication liquid application unit 105 and the source of the scattering of the fabrication material are monitored, the falling speed of the fabrication material is controlled, the source is controlled considering the characteristics of the size and the weight of the fabrication material, and the like. Therefore, it is possible to reduce the scattering amount of the fabrication material, and prevent a case where the fabrication liquid is not discharged properly or the fabrication material takes the shape of an icicle, which influences the quality of the three-dimensional fabricated object that is the finished product. Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.
Any one of the above-described operations may be performed in various other ways, for example, in an order different from the one described above.
Number | Date | Country | Kind |
---|---|---|---|
2021-213266 | Dec 2021 | JP | national |