A control device and control method suitable for bidirectional powder spreading stable flow field

Abstract

The present invention discloses a control device and a control method for a bidirectional powder spreading stable flow field, including a forming cabin, an optical module is arranged above the forming cabin, a powder supply module is connected to the forming cabin, a forming cylinder and a powder collecting module are connected below the forming cabin, a lifting platform is arranged in the forming cylinder, two virtual scraper racks are arranged in the forming cabin, a scraper rack is arranged between the two virtual scraper racks, and a positioning module for limiting the movement distance of the virtual scraper rack and the scraper rack is arranged at the bottom of the forming cabin. Virtual scrapers are arranged on both sides of the scraper, so that after each powder spreading, the scraper on either side of the forming area can form a stable and consistent structure with the virtual scraper on the opposite side to ensure the stability of the flow field and improve the forming quality of the parts; the scraper and the virtual scraper can adopt synchronous or asynchronous motion, and the operation is smooth.

Description

Technical Field

[0001] The present invention belongs to the technical field of 3D printing equipment, and relates to a control device suitable for a bidirectional powder spreading stable flow field, and also relates to a control method of the control device. Background Art

[0002] SLM technology processes parts by adding materials, quickly, directly and accurately transforming design ideas into physical models with certain functions. Compared with traditional processing methods, SLM can shorten product design and manufacturing cycles, improve corporate competitiveness, and enhance corporate profitability, establishing a new product development model for industrial product designers and developers.

[0003] During the entire forming process of the SLM equipment, a stable flow field needs to be formed to ensure that large particles and smoke dust in the printing process are taken away in time, to ensure that the atmosphere in the forming chamber is clean, the flow field is consistent, and the quality of part forming is ensured. For one-way powder spreading equipment, during the printing process, the scraper always stops on one side of the forming area, so the flow field structure of each layer is consistent and stable. However, for two-way powder spreading, when the scraper is on different sides, the entire structural morphology in the forming chamber cavity changes, so there will be certain differences in the flow field. For equipment with a larger forming chamber cavity, such as large forming size equipment, the difference in the flow field on both sides of the scraper may cause inconsistent forming of parts separated by two layers, affecting the forming quality of the parts. Summary of the invention

[0004] The purpose of the present invention is to provide a control device suitable for a stable flow field of bidirectional powder spreading, which solves the problem in the prior art that flow field differences in the bidirectional powder spreading process affect the forming quality.

[0005] The technical solution adopted by the present invention is a control device suitable for a bidirectional powder spreading stable flow field, including a forming cabin, an optical module is arranged above the forming cabin, a powder supply module is connected to the forming cabin, a forming cylinder and a powder collecting module are connected below the forming cabin, a lifting platform is arranged in the forming cylinder, and it is characterized in that two virtual scraper frames are arranged in the forming cabin, a scraper frame is arranged between the two virtual scraper frames, and a positioning module for limiting the movement distance of the virtual scraper frames and the scraper frames is arranged at the bottom of the forming cabin.

[0006] The present invention is also characterized in that:

[0007] The positioning module comprises a first position sensor, a second position sensor, a third position sensor and a fourth position sensor which are arranged in sequence. The first position sensor and the fourth position sensor are symmetrically arranged, and the second position sensor and the third position sensor are symmetrically arranged.

[0008] The powder supply module comprises a powder loading and unloading mechanism, and the powder loading and unloading mechanism is fixed on the top of the forming cabin.

[0009] The powder supply module comprises a lower powder ejecting mechanism, which is fixed below the forming cabin.

[0010] The powder collecting module comprises a powder collecting barrel, and the powder collecting barrel is fixed below the forming cabin.

[0011] Another object of the present invention is to provide a control method suitable for a bidirectional powder spreading stable flow field.

[0012] Another technical solution adopted by the present invention is a control method suitable for a bidirectional powder spreading stable flow field, which specifically comprises the following steps:

[0013] Step 1: The lifting platform descends one floor;

[0014] Step 2, control the scraper frame to spread the powder in the forward direction, and when the powder spreading is completed, move the scraper frame to the third position sensor, and move the two virtual scraper frames to the second position sensor and the fourth position sensor respectively;

[0015] Step 3: Start printing. If it is the last layer, the printing task is completed.

[0016] Step 4: Otherwise, the lifting platform descends one floor;

[0017] Step 5, control the scraper frame to spread powder in the reverse process, and when the powder spreading is completed, the scraper frame is located at the second position sensor, and the two virtual scraper frames are respectively located at the first position sensor and the third position sensor;

[0018] Step 6: Start printing. If it is the last layer, the printing task is completed.

[0019] Step 7. Otherwise, repeat steps 1-6.

[0020] The powder spreading process of step 2 is specifically as follows: when a virtual scraper frame is detected to move to the fourth position sensor, the virtual scraper frame stops; the scraper frame is controlled to spread powder in the forward direction, and when the scraper frame is detected to move to the third position sensor, the scraper frame stops; another virtual scraper frame starts to move toward the second position sensor, and stops when it reaches the second position sensor;

[0021] The powder spreading process of step 5 is specifically as follows: the virtual scraper frame located at the second position sensor starts to move toward the first position sensor, and stops after reaching the first position sensor; the scraper frame is controlled to spread powder in the reverse direction, and when it is detected that the scraper frame reaches the second position sensor, the scraper frame stops; another virtual scraper frame starts to move toward the third position sensor, and stops when it reaches the target position.

[0022] The powder spreading process of step 2 is specifically as follows: the scraper holder is controlled to spread the powder in the forward direction, and the scraper holder and the two virtual scraper holders move forward at the same time, and the process ends when it is detected that the scraper holder is located at the third position sensor and the two virtual scraper holders are located at the second position sensor and the fourth position sensor respectively;

[0023] The powder spreading process of step 5 is specifically as follows: controlling the scraper frame and the two virtual scraper frames to move back simultaneously, and ending when it is detected that the scraper frame is located at the second position sensor and the two virtual scraper frames are respectively located at the first position sensor and the third position sensor.

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides a control device suitable for a stable flow field of bidirectional powder spreading, in which virtual scrapers are arranged on both sides of the scraper, so that after each powder spreading, the scraper on either side of the forming area can form a stable and consistent structure with the virtual scraper on the opposite side to ensure the stability of the flow field and improve the forming quality of the parts; the present invention provides a control method suitable for a stable flow field of bidirectional powder spreading, in which the scraper and the virtual scraper can adopt synchronous or asynchronous motion and run smoothly. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a control device suitable for a bidirectional powder spreading stable flow field according to the present invention;

[0027] Figure 2 It is a structural schematic diagram of a scraper in a control device for a bidirectional powder spreading stable flow field according to the present invention;

[0028] Figure 3 It is a top view of a control device for a bidirectional powder spreading stable flow field according to the present invention;

[0029] Figure 4 It is a working schematic diagram of a control device for a bidirectional powder spreading stable flow field according to the present invention;

[0030] Figure 5 It is a flow chart of a control method for a bidirectional powder spreading stable flow field according to the present invention;

[0031] Figure 6 It is a flow chart of another embodiment of a control method for a bidirectional powder spreading stable flow field according to the present invention.

[0032] In the figure, 1. forming cabin, 2. optical module, 3. powder supply module, 3-1. powder dropping mechanism, 3-2. powder pushing mechanism, 4. forming cylinder, 5. lifting platform, 6. virtual scraper holder, 7. scraper holder, 8. first driving mechanism, 9. second driving mechanism, 10. powder collecting module, 11. first position sensor, 12. second position sensor, 13. third position sensor, 14. fourth position sensor, 15. forming area, 16. parts. DETAILED DESCRIPTION

[0033] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] The present invention provides a control device suitable for a bidirectional powder spreading stable flow field, such as Figure 1 As shown, it includes a forming cabin 1, an optical module 2 is arranged above the forming cabin 1 for outputting laser to realize powder melting; the forming cabin 1 is connected to a powder supply module 3, the forming cabin 1 is connected to a forming cylinder 4 and a powder collecting module 10 below, a lifting platform 5 is arranged in the forming cylinder 4, two virtual scraper frames 6 are arranged in the forming cabin 1, and a scraper frame 7 is arranged between the two virtual scraper frames 6, Figure 2 Figure 7(a) is a schematic diagram of the scraper frame for one-way powder spreading, and Figure 7(b) is a schematic diagram of the scraper frame for two-way powder spreading. Figure 3 As shown, it also includes a first driving mechanism 8 for driving the virtual scraper frame 6 and a second driving mechanism 9 for driving the scraper frame 7. A positioning module for limiting the movement distance of the virtual scraper frame 6 and the scraper frame 7 is set at the bottom of the forming chamber 1.

[0035] like Figure 4 As shown, the positioning module includes a first position sensor 11 (position 3), a second position sensor 12 (position 1), a third position sensor 13 (position 2), and a fourth position sensor 14 (position 4) arranged in sequence. The first position sensor 11 and the fourth position sensor 14 are symmetrically arranged, which are the parking positions when the virtual scraper frame 6 is not in effect; the second position sensor 12 and the third position sensor 13 are symmetrically arranged, which are the target positions on both sides of the forming area 15 where the scraper frame 7 ends powder spreading. The third position sensor 13 between the second position sensor 12 is the forming area 15.

[0036] The powder supply module 3 is a powder dropping mechanism or a powder pushing mechanism.

[0037] The powder supply module 3 includes a powder loading and unloading mechanism 3-1, which is fixed to the top of the forming chamber 1. The number of the powder loading and unloading mechanism 3-1 can be one or two.

[0038] The powder supply module 3 may also include a lower powder pushing mechanism 3-2, which is fixed below the forming cabin 1 and located in the forming cylinder 4. The number of the lower powder pushing mechanism 3-2 may be one or two.

[0039] The powder collecting module 10 includes powder collecting barrels, which are respectively fixed below the forming chamber 1 and are located outside the lower powder ejecting mechanism 3 - 2 .

[0040] The present invention provides a stable flow field control method suitable for bidirectional powder spreading, which specifically comprises the following steps:

[0041] Step 1, control the lifting platform 5 to descend one floor;

[0042] Step 2, control the scraper frame 7 to spread the powder in the forward direction. When the powder spreading is completed, the scraper frame 7 moves to the third position sensor 13 (position 2), and the two virtual scraper frames 6 move to the second position sensor 12 (position 1) and the fourth position sensor 14 (position 4) respectively;

[0043] Step 3, start printing;

[0044] If it is the last layer, the printing task is completed;

[0045] Step 4: Otherwise, the lifting platform descends one floor;

[0046] Step 5, control the scraper frame 7 to spread powder in the reverse process. When the powder spreading is completed, the scraper frame 7 is located at the second position sensor 12 (position 1), and the two virtual scraper frames 6 are respectively located at the first position sensor 11 (position 3) and the third position sensor 13 (position 2);

[0047] Step 5: Start printing. If it is the last layer, the printing task is completed.

[0048] Step 6. Otherwise, repeat steps 1-5.

[0049] Through the above manner, a control device suitable for a stable flow field of bidirectional powder spreading of the present invention is provided, in which virtual scrapers are arranged on both sides of the scraper, so that after each powder spreading, the scraper on either side of the forming area can form a stable and consistent structure with the virtual scraper on the opposite side to ensure the stability of the flow field and improve the forming quality of the parts; a control method suitable for a stable flow field of bidirectional powder spreading of the present invention, in which the scraper and the virtual scraper can adopt synchronous or asynchronous motion and run smoothly.

[0050] Example 1

[0051] like Figure 5 As shown, when asynchronous control is adopted, the X direction is defined as the positive direction, and the control method is as follows:

[0052] First turn on the SLM device and initialize it;

[0053] Step 1, control the lifting platform 5 to descend one floor;

[0054] Step 2, move the right virtual scraper frame 6 in the X direction; when it is detected that the virtual scraper frame 6 reaches position 4 (the virtual scraper frame 6 is named A), the virtual scraper frame 6-A stops moving, and the scraper frame 7 moves in the X direction to start spreading powder; when it is detected that the scraper frame 7 moves to position 2, the scraper frame 7 stops moving, and the left virtual scraper frame 6 starts to move in the X direction (the virtual scraper frame 6 is named B), and stops after reaching position 1;

[0055] Step 3: If the printing starts at the last layer, the printing task is completed;

[0056] Step 4: Otherwise, the lifting platform descends one floor;

[0057] Step 5, the left virtual scraper frame 6-B starts to move in the -X direction; when it is detected that the virtual scraper frame 6-B has reached position 3, the virtual scraper frame 6-B stops moving, and the scraper frame 7 is controlled to spread powder in the -X direction in the reverse direction; when it is detected that the scraper frame 7 has reached position 1, the scraper frame 7 stops moving, and the right virtual scraper frame 6-A starts to move in the -X direction and stops at position 2;

[0058] Step 6: Start printing. If it is the last layer, the printing task is completed.

[0059] Step 7. Otherwise, repeat steps 1-6.

[0060] The powder supply in the scraper frame 7 can be carried out after the previous layer of powder is spread and before the next layer of powder is spread. Powder supply can be performed once for each layer of powder spreading, or after several layers of powder spreading, and the powder supply form is not limited. If it is a one-way powder spreading, the difference from the two-way powder spreading is that the right virtual scraper frame 6-A does not move after moving to position 4, and the scraper frame 7 does not spread powder when moving in the -X direction.

[0061] In the above control method, the scraper holder and the virtual scraper holder move asynchronously, and the powder spreading time is relatively longer, but the control is simpler.

[0062] like Figure 6 As shown in the figure, when synchronous control is adopted, the control method is as follows:

[0063] First turn on the SLM device and initialize it;

[0064] Step 1, control the lifting platform 5 to descend one floor;

[0065] Step 2, when it is detected that the scraper holder 7 moves to position 1, the scraper holder 7 is controlled to spread powder in the forward direction, and the scraper holder 7, the virtual scraper 6-A and the virtual scraper 6-B move in the X direction at the same time, and the process ends when it is detected that the scraper holder 7 is at position 2, the virtual scraper holder 6-B is at position 1, and the virtual scraper 6-A is at position 4;

[0066] Step 3: Start printing; if it is the last layer, the printing task is completed;

[0067] Step 4: Otherwise, the lifting platform descends one floor;

[0068] Step 5, the scraper holder 7, the virtual scraper 6-A and the virtual scraper 6-B simultaneously move back in the -X direction, and the process ends when it is detected that the scraper holder 7 is at position 1, the virtual scraper A is at position 2, and the virtual scraper B and the virtual scraper holder 6 are at position 3;

[0069] Step 6: Start printing. If it is the last layer, the printing task is completed.

[0070] Step 7. Otherwise, repeat steps 1-6.

[0071] In the above control method, the scraper frame 7 and the virtual scraper frame 6 move synchronously, and the operation is more efficient. During the operation, the speed can be set to ensure that the three scrapers do not contact each other.

Claims

1. A control device for a bidirectional powder spreading stable flow field, comprising a forming cabin (1), an optical module (2) is arranged above the forming cabin (1), a powder supply module (3) is connected to the forming cabin (1), a forming cylinder (4) and a powder collecting module (10) are connected below the forming cabin (1), a lifting platform (5) is arranged inside the forming cylinder (4), and the device is characterized in that: Two virtual scraper frames (6) are arranged in the forming chamber (1), a scraper frame (7) is arranged between the two virtual scraper frames (6), and a positioning module for limiting the movement distance of the virtual scraper frames (6) and the scraper frames (7) is arranged at the bottom of the forming chamber (1); The positioning module comprises a first position sensor (11), a second position sensor (12), a third position sensor (13), and a fourth position sensor (14) arranged in sequence, the first position sensor (11) and the fourth position sensor (14) being symmetrically arranged, and the second position sensor (12) and the third position sensor (13) being symmetrically arranged; The powder supply module (3) comprises a powder dropping mechanism (3-1), wherein the powder dropping mechanism (3-1) is fixed on the top of the forming chamber (1); The powder supply module (3) comprises a lower powder pushing mechanism (3-2), and the lower powder pushing mechanism (3-2) is fixed below the forming chamber (1); The powder collecting module (10) comprises a powder collecting barrel, and the powder collecting barrel is fixed below the forming chamber (1).

2. A stable flow field control method suitable for bidirectional powder spreading, characterized in that: The specific steps include: Step 1, the lifting platform (5) descends one floor; Step 2, controlling the scraper frame (7) to spread the powder in a forward direction, and when the powder spreading is completed, causing the scraper frame (7) to move to the third position sensor (13), and the two virtual scraper frames (6) to move to the second position sensor (12) and the fourth position sensor (14), respectively; Step 3: Start printing. If it is the last layer, the printing task is completed. Step 4: Otherwise, the lifting platform (5) descends one floor; Step 5, controlling the scraper frame (7) to spread powder in the reverse process, and when the powder spreading is completed, the scraper frame (7) is located at the second position sensor (12), and the two virtual scraper frames (6) are respectively located at the first position sensor (11) and the third position sensor (13); Step 6: Start printing. If it is the last layer, the printing task is completed. Step 7. Otherwise, repeat steps 1-6.

3. A stable flow field control method suitable for bidirectional powder spreading according to claim 2, characterized in that: The powder spreading process described in step 2 is specifically as follows: when a virtual scraper frame (6) is detected to move to the fourth position sensor (14), the virtual scraper frame (6) stops; the scraper frame (7) is controlled to spread powder in the forward direction, and when the scraper frame (7) is detected to move to the third position sensor (13), the scraper frame (7) stops; another virtual scraper frame (6) starts to move toward the second position sensor (12) and stops when it reaches the target position; The powder spreading process described in step 5 is specifically as follows: the virtual scraper frame (6) located at the second position sensor (12) starts to move toward the first position sensor (11), and after reaching the target position, the virtual scraper frame (6) stops; the scraper frame (7) is controlled to spread the powder in the reverse direction, and when it is detected that the scraper frame (7) reaches the second position sensor (12), the scraper frame (7) stops; another virtual scraper frame (6) starts to move toward the third position sensor (13), and stops when it reaches the target position.

4. A stable flow field control method suitable for bidirectional powder spreading according to claim 2, characterized in that: The powder spreading process of step 2 is specifically as follows: controlling the scraper frame (7) to spread the powder in a forward direction, and the scraper frame (7) and the two virtual scraper frames (6) move forward at the same time, and the process ends when it is detected that the scraper frame (7) is located at the third position sensor (13) and the two virtual scraper frames (6) are respectively located at the second position sensor (12) and the fourth position sensor (14); The powder spreading process of step 5 is specifically as follows: controlling the scraper frame (7) and the two virtual scraper frames (6) to move in a return direction simultaneously, and ending when it is detected that the scraper frame (7) is located at the second position sensor (12) and the two virtual scraper frames (6) are respectively located at the first position sensor (11) and the third position sensor (13).

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