Rapid powder spreading method for powder bed additive manufacturing equipment

Abstract

The invention discloses a rapid powder spreading method for powder bed additive manufacturing equipment, which comprises the following steps: step A, a powder supply cylinder piston moves upwards and pushes out powder, and a scraper stops above a powder overflow channel; b, the scraper moves towards the powder supply cylinder, and the pushed-out powder is shaped into a powder pile; c, after the piston of the powder supply cylinder descends, the scraper moves to the position above the powder pile; d, the powder supply cylinder piston ascends, the powder pile is pushed into the powder containing space, and the forming cylinder piston descends by one layer thickness; e, the scraper carries the powder pile to move towards the forming cylinder, powder laying operation is carried out, and laser sintering is carried out after powder laying is completed; f, after one layer is sintered, a piston of the forming cylinder descends by one layer thickness, the scraper carries the powder pile to do return motion and conduct powder laying operation, the rear scraper stops above the powder overflowing channel, and redundant powder in the powder containing space falls into the powder overflowing channel; and G, the steps A-F are repeated till printing is finished. Rapid two-way powder laying of downward powder feeding is achieved, and the printing efficiency is greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive manufacturing, and in particular relates to a rapid powder spreading method for a powder bed additive manufacturing device. Background Art

[0002] Powder bed additive manufacturing equipment, especially dual-cylinder bottom powder feeding equipment, is generally not equipped with a two-way powder spreading function. This results in the scraper always having to move the empty stroke back to the edge of the powder supply cylinder after each layer of laser scanning is completed. This process significantly increases the printing time. The current conventional two-way powder spreading equipment is generally based on the principle of upper powder feeding, with a quantitative powder dropping device or a movable partition to control the powder to fall into the powder spreading trough for two-way powder spreading, which can significantly improve the printing efficiency. However, the structures of these devices are relatively complex, and the amount of powder dropped is difficult to accurately control. When the powder supply is too large, it is easy to cause powder waste, and when the powder supply is insufficient, it causes powder shortage. And due to the complex channel design, it is very time-consuming to clean the equipment when replacing heterogeneous powders. In order to solve the problem of two-way powder spreading of bottom powder feeding, the present invention realizes rapid two-way powder spreading without using complex structures and devices, greatly improving the printing efficiency. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a rapid powder spreading method for powder bed additive manufacturing equipment. The present invention realizes rapid two-way powder spreading by downward powder feeding without using complex structures and devices, thereby greatly improving printing efficiency.

[0004] In order to achieve the above-mentioned object, the present invention provides a rapid powder spreading method for a powder bed additive manufacturing device, the powder bed additive manufacturing device comprising a powder supply cylinder, a forming cylinder, a powder supply cylinder piston, a forming cylinder piston, a scraper and an overflow powder channel, the powder supply cylinder and the forming cylinder are located on the same plane above, and the scraper is tangent to the plane below; the scraper comprises a first sub-scraper and a second sub-scraper arranged parallel to the first sub-scraper, and a powder holding space is formed between the first sub-scraper and the second sub-scraper; the rapid powder spreading method comprises the following steps:

[0005] Step A: The piston of the powder supply cylinder moves upward by a distance n and pushes the powder out of the powder supply cylinder. At this time, the scraper stops above the overflow powder channel;

[0006] Step B: The scraper moves a distance m toward the powder supply cylinder to shape the powder pushed out of the powder supply cylinder into a powder pile;

[0007] Step C: The piston of the powder supply cylinder drops to a height z, and the rear scraper moves to the top of the powder pile;

[0008] Step D: The piston of the powder supply cylinder rises to a height z, at which point the powder pile is pushed into the powder holding space of the scraper, and at the same time the piston of the forming cylinder descends to a layer thickness h;

[0009] Step E: The scraper carries the powder pile toward the forming cylinder to spread the powder. The powder height of the forming cylinder becomes one layer higher. After the powder is spread, the laser performs sintering.

[0010] Step F: After sintering one layer, the piston of the forming cylinder descends by a layer thickness h, and the scraper carries the powder pile to make a return motion to perform the powder spreading operation. The powder height of the forming cylinder becomes higher by a layer thickness h. After the powder spreading is completed, the laser performs sintering, and the scraper stops above the powder overflow channel. The excess powder in the powder holding space of the scraper falls into the powder overflow channel;

[0011] Step G: Repeat steps AF until printing is complete.

[0012] Preferably, the amount of powder pushed out by the powder supply cylinder in step A is equal to the sum of the amount of powder spread on the forming cylinder in step E, the amount of powder spread on the forming cylinder in step F and the amount of powder recovered in the overflow powder channel in step F.

[0013] Preferably, the distance n that the powder supply cylinder piston moves upward is 0.01-5 mm.

[0014] Preferably, the distance m that the scraper moves toward the powder supply cylinder is 1-200 mm.

[0015] Preferably, the height z of the powder supply cylinder piston's descent and ascent is 0.01-50 mm.

[0016] Preferably, the layer thickness h is 0.01-5 mm.

[0017] Preferably, the first sub-scraper is connected to the second sub-scraper at the top, and the cross-section of the scraper is an inverted U-shaped structure.

[0018] The present invention provides a rapid powder spreading method for a powder bed additive manufacturing device, which adopts a double parallel scraper to cooperate with a powder supply cylinder piston, and uses the double parallel scraper to shape the powder in the powder supply cylinder. The shaped powder is located between the double parallel scrapers, so that the double parallel scrapers carry a certain amount of powder at one time for moving powder spreading. Without using complex structures and devices, rapid two-way powder spreading of downward powder feeding is achieved, greatly improving printing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1The figure is a flow chart of the rapid powder spreading method of the present invention.

[0021] The above reference numerals:

[0022] 1. Piston of forming cylinder; 2. Piston of powder supply cylinder; 3. Overflow powder channel; 4. Powder of forming cylinder; 5. Parts; 6. Powder of powder supply cylinder; 7. Scraper; 70. First sub-scraper; 71. Second sub-scraper; 8. Powder pile; 9. Laser. DETAILED DESCRIPTION

[0023] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings.

[0024] like Figure 1 As shown, the present invention provides a rapid powder spreading method for a powder bed additive manufacturing device, the powder bed additive manufacturing device comprises a powder supply cylinder, a forming cylinder, a powder supply cylinder piston 2, a forming cylinder piston 1, a scraper 7 and a powder overflow channel 3, the powder supply cylinder and the forming cylinder are located on the same plane above, and the scraper 7 is tangent to the plane below; the scraper 7 comprises a first sub-scraper 70 and a second sub-scraper 71 arranged parallel to the first sub-scraper 70, and a powder containing space is formed between the first sub-scraper 70 and the second sub-scraper 71; the rapid powder spreading method comprises the following steps:

[0025] Step A: The powder supply cylinder piston 2 moves upward by a distance n and pushes out the powder 6 from the powder supply cylinder. At this time, the scraper 7 stops above the overflow powder channel 3;

[0026] Step B: The scraper 7 moves toward the powder supply cylinder by a distance m, and shapes the powder 6 pushed out of the powder supply cylinder into a powder pile 8;

[0027] Step C: the piston 2 of the powder supply cylinder descends to a height z, and the rear scraper 7 moves to the top of the powder pile 8;

[0028] Step D: The piston 2 of the powder supply cylinder rises to a height z, at which time the powder pile 8 is pushed into the powder holding space of the scraper 7, and at the same time the piston 1 of the forming cylinder descends by a layer thickness h;

[0029] Step E: The scraper 7 carries the powder pile 8 and moves toward the forming cylinder to perform the powder spreading operation. The height of the powder 4 in the forming cylinder becomes higher by one layer thickness. After the powder spreading is completed, the laser 9 performs sintering;

[0030] Step F: After sintering one layer, the piston 1 of the forming cylinder descends by a layer thickness h, and the scraper 7 carries the powder pile 8 to make a return movement to perform a powder spreading operation. The height of the powder 4 in the forming cylinder becomes higher by a layer thickness h. After the powder spreading is completed, the laser 9 performs sintering, and the scraper 7 stops above the overflow powder channel 3. The excess powder in the powder holding space of the scraper 7 falls into the overflow powder channel 3;

[0031] Step G: Repeat steps AF until printing is complete.

[0032] The present invention adopts double parallel scrapers 7 to cooperate with the powder supply cylinder piston 2, and uses the double parallel scrapers to shape the powder 6 in the powder supply cylinder. The shaped powder is located between the double parallel scrapers, so that the double parallel scrapers carry a certain amount of powder at one time for moving powder spreading. Without using complex structures and devices, rapid two-way powder spreading of downward powder feeding is achieved, greatly improving printing efficiency.

[0033] Obviously, the amount of powder pushed out by the powder supply cylinder in step A is equal to the sum of the amount of powder spread on the forming cylinder in step E, the amount of powder spread on the forming cylinder in step F and the amount of powder recovered in the overflow powder channel 3 in step F.

[0034] In this embodiment, the distance n that the powder supply cylinder piston 2 moves upward is 0.01-5 mm.

[0035] In this embodiment, the distance m that the scraper 7 moves toward the powder supply cylinder is 1-200 mm.

[0036] In this embodiment, the height z of the powder supply cylinder piston 2 descending and ascending is 0.01-50 mm.

[0037] In this embodiment, the layer thickness h is 0.01-5 mm.

[0038] In this embodiment, the first sub-scraper 70 and the second sub-scraper 71 are connected at the top, and the cross section of the scraper 7 is an inverted U-shaped structure.

[0039] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Embodiment 1:

[0041] The rapid powder spreading method of this embodiment comprises the following steps:

[0042] Step A: There is forming cylinder powder 4 on the forming cylinder piston 1, in which there is a part 5 being processed by the laser 9. At this time, the powder supply cylinder piston 2 moves upward by 0.15 mm and pushes out the powder supply cylinder powder 6. At this time, the scraper 7 stops above the overflow powder channel 3;

[0043] Step B: The scraper 7 moves 50 mm toward the powder supply cylinder (towards the left) to shape the powder 6 pushed out of the powder supply cylinder into a powder pile 8;

[0044] Step C: The piston 2 of the powder supply cylinder descends by 20 mm, and the rear scraper 7 moves to the top of the powder pile 8;

[0045] Step D: The piston 2 of the powder supply cylinder rises by 20 mm, at which time the powder pile 8 is pushed into the powder holding space of the scraper 7, and at the same time the piston 1 of the forming cylinder descends by a layer thickness of 0.05 mm;

[0046] Step E: The scraper 7 carries the powder pile 8 and moves toward the forming cylinder (to the left) to perform the powder spreading operation. The height of the powder 4 in the forming cylinder increases by a layer thickness of 0.05 mm. After the powder spreading is completed, the laser 9 performs sintering;

[0047] Step F: After sintering one layer, the piston 1 of the forming cylinder descends by a layer thickness of 0.05 mm, and the scraper 7 carries the powder pile 8 to make a return motion (move to the right) to perform a powder spreading operation. The height of the powder 4 in the forming cylinder becomes higher by a layer thickness of 0.05 mm. After the powder spreading is completed, the laser 9 performs sintering, and the scraper 7 stops above the overflow powder channel 3. The excess powder in the powder holding space of the scraper 7 falls into the overflow powder channel 3;

[0048] Step G: Repeat steps AF until printing is complete.

[0049] In this embodiment, the laser 9 processes each layer for no less than 3 minutes, and the powder shaping time is less than 30 seconds. Powder shaping can be performed synchronously during the printing process, that is, the laser 9 can perform steps A and B at the same time during the printing process. The scraper 7 can carry the powder and move left and right to spread the powder. In the conventional one-way powder spreading operation, the laser 9 needs to stop emitting light for 20 seconds to wait for powder supply and spreading, but now it only takes 9 seconds to complete, which greatly improves the printing efficiency.

[0050] Embodiment 2:

[0051] The rapid powder spreading method of this embodiment comprises the following steps:

[0052] Step A: There is forming cylinder powder 4 on the forming cylinder piston 1, in which there is a part 5 being processed by the laser 9. At this time, the powder supply cylinder piston 2 moves upward by 0.3 mm and pushes out the powder supply cylinder powder 6. At this time, the scraper 7 stops above the overflow powder channel 3;

[0053] Step B: The scraper 7 moves 100 mm toward the powder supply cylinder (towards the left) to shape the powder 6 pushed out of the powder supply cylinder into a powder pile 8;

[0054] Step C: The piston 2 of the powder supply cylinder descends by 15 mm, and the rear scraper 7 moves to the top of the powder pile 8;

[0055] Step D: The piston 2 of the powder supply cylinder rises 15 mm, at which time the powder pile 8 is pushed into the powder holding space of the scraper 7, and at the same time the piston 1 of the forming cylinder descends by a layer thickness of 0.06 mm;

[0056] Step E: The scraper 7 carries the powder pile 8 and moves toward the forming cylinder (to the left) to perform the powder spreading operation. The height of the powder 4 in the forming cylinder increases by a layer thickness of 0.06 mm. After the powder spreading is completed, the laser 9 performs sintering;

[0057] Step F: After sintering one layer, the forming cylinder piston 1 descends by a layer thickness of 0.06 mm, and the scraper 7 carries the powder pile 8 to make a return motion (move to the right) to perform a powder spreading operation. The height of the powder 4 in the forming cylinder becomes higher by a layer thickness of 0.06 mm. After the powder spreading is completed, the laser 9 performs sintering, and the scraper 7 stops above the overflow powder channel 3. The excess powder in the powder holding space of the scraper 7 falls into the overflow powder channel 3;

[0058] Step G: Repeat steps AF until printing is complete.

[0059] In this embodiment, the laser 9 processes each layer for no less than 3 minutes, and the powder shaping time is less than 50 seconds. Powder shaping can be performed synchronously during the printing process, that is, the laser 9 can perform steps A and B at the same time during the printing process. The scraper 7 can carry the powder and move left and right to spread the powder. In the conventional one-way powder spreading operation, the laser 9 needs to stop emitting light for 20 seconds to wait for powder supply and spreading, but now it only takes 9 seconds to complete, which greatly improves the printing efficiency.

[0060] The present invention provides a rapid powder spreading method for a powder bed additive manufacturing device, the powder bed additive manufacturing device comprises a powder supply cylinder, a forming cylinder, a powder supply cylinder piston 2, a forming cylinder piston 1, a roller and a powder overflow channel 3, the upper parts of the powder supply cylinder and the forming cylinder are in the same plane, and the lower part of the roller is tangent to the plane; the roller comprises a first sub-roller and a second sub-roller arranged parallel to the first sub-roller, and a powder containing space is formed between the first sub-roller and the second sub-roller. The rapid powder spreading method of this powder bed additive manufacturing device is the same as that described in detail in the above-mentioned powder bed additive manufacturing device, so it is not repeated here.

[0061] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A rapid powder spreading method for a powder bed additive manufacturing device, the powder bed additive manufacturing device comprising a powder supply cylinder, a forming cylinder, a powder supply cylinder piston (2), a forming cylinder piston (1), a scraper (7) and an overflow powder channel (3), wherein the upper parts of the powder supply cylinder and the forming cylinder are in the same plane, and the lower part of the scraper (7) is tangent to the plane; characterized in that: The scraper (7) comprises a first sub-scraper (70) and a second sub-scraper (71) arranged parallel to the first sub-scraper (70), and a powder holding space is formed between the first sub-scraper (70) and the second sub-scraper (71); the rapid powder spreading method comprises the following steps: Step A: The powder supply cylinder piston (2) moves upward a distance n and pushes the powder (6) out of the powder supply cylinder. At this time, the scraper (7) stops above the overflow powder channel (3); Step B: The scraper (7) moves a distance m toward the powder supply cylinder to shape the powder (6) pushed out of the powder supply cylinder into a powder pile (8); Step C: the piston of the powder supply cylinder (2) descends to a height z, and the rear scraper (7) moves to the top of the powder pile (8); Step D: The piston (2) of the powder supply cylinder rises to a height z, at which time the powder pile (8) is pushed into the powder holding space of the scraper (7), and at the same time the piston (1) of the forming cylinder descends to a layer thickness h; Step E: The scraper (7) carries the powder pile (8) toward the forming cylinder to perform a powder spreading operation, and the height of the powder (4) in the forming cylinder becomes higher by one layer thickness. After the powder spreading is completed, the laser (9) performs sintering; Step F: After sintering a layer, the piston (1) of the forming cylinder descends by a layer thickness h, and the scraper (7) carries the powder pile (8) to make a return motion to perform a powder spreading operation. The height of the powder (4) in the forming cylinder increases by a layer thickness. After the powder spreading is completed, the laser (9) performs sintering, and the scraper (7) stops above the powder overflow channel (3). The excess powder in the powder holding space of the scraper (7) falls into the powder overflow channel (3); Step G: Repeat steps AF until printing is complete.

2. The rapid powder spreading method according to claim 1, characterized in that: The amount of powder pushed out by the powder supply cylinder in step A is equal to the sum of the amount of powder spread on the forming cylinder in step E, the amount of powder spread on the forming cylinder in step F and the amount of powder recovered in the overflow powder channel (3) in step F.

3. The rapid powder spreading method for powder bed additive manufacturing according to claim 1, characterized in that: The distance that the powder supply cylinder piston (2) moves upward is 0.01-5 mm.

4. The rapid powder spreading method for powder bed additive manufacturing according to claim 1, characterized in that: The distance m that the scraper (7) moves toward the powder supply cylinder is 1-200 mm.

5. The rapid powder spreading method for powder bed additive manufacturing according to claim 1, characterized in that: The height z of the powder supply cylinder piston (2) when it descends and rises is 0.01-50 mm.

6. The rapid powder spreading method for powder bed additive manufacturing according to claim 1, characterized in that: The layer thickness h is 0.01-5 mm.

7. The rapid powder spreading method according to claim 1, characterized in that: The first sub-scraper (70) and the second sub-scraper (71) are connected at the top, and the cross section of the scraper (7) is an inverted U-shaped structure.

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