A powder spreading device

Abstract

This utility model provides a powder spreading device, relating to additive manufacturing, comprising: a scraper frame with a powder inlet at the top and left and right powder bins on both sides; the powder inlet has multiple spaced-apart left and right powder inlet channels, each left powder inlet channel connecting to a left powder bin at its lower end, and each right powder inlet channel connecting to a right powder bin at its lower end; a scraper fixedly mounted at the bottom of the scraper frame and located between the left and right powder bins; a powder dropping plate movably mounted at the bottom of the scraper frame, having a through-hole and two powder dropping holes through which the scraper passes; and a drive mechanism connected to the powder dropping plate to drive its movement. Movement of the powder dropping plate to the right aligns one powder dropping hole with the lower end of the right powder bin, while movement of the powder dropping plate to the left aligns the other powder dropping hole with the lower end of the left powder bin. The advantages of this utility model include: reduced molding risk, guaranteed molding quality, balanced powder spreading efficiency and quality, and improved powder utilization.

Description

Technical Field

[0001] This utility model relates to the field of additive manufacturing technology, and in particular to a powder spreading device. Background Technology

[0002] The powder spreading device is an important component of metal additive manufacturing technology. It uses a doctor blade assembly to spread technical powder onto the printing area according to the process layer thickness. A laser then sintersulates the metal powder in the printing area in an inert atmosphere to form the part layer by layer.

[0003] Currently, a common powder spreading device employs single-blade bidirectional powder spreading technology. In this technology, at least two layers of powder fall in front of the squeegee in the powder receiving area. The squeegee moves unidirectionally from the powder receiving area to the printing area, spreading the powder evenly. Laser sintering then completes the process. The squeegee then reverses direction or uses powder avoidance and lifting techniques to ensure the powder is in front of the squeegee's return direction. After sintering, the squeegee returns from the printing area to the powder receiving area, where laser sintering is performed again, and the squeegee receives the remaining powder. While bidirectional powder spreading is far more efficient than unidirectional spreading, the squeegee position and the laser focal plane directly affect print quality. Bidirectional spreading places higher demands on the process compared to unidirectional spreading, and it's easy to scrape the surface of the part. Furthermore, ensuring bidirectional powder spreading through squeegee reversal makes it difficult to guarantee consistent squeegee positioning, increasing the risk of defects. The powder avoidance and lifting techniques, which keep the powder in front of the squeegee's return direction, make the powder susceptible to contamination from previous printing processes, indirectly affecting print quality. Utility Model Content

[0004] In view of this, in order to solve the above-mentioned problems of single-blade bidirectional powder spreading technology in additive manufacturing, the present invention provides a powder spreading device.

[0005] An embodiment of this utility model provides a powder spreading device, comprising:

[0006] The scraper holder has a powder inlet at the top and left and right powder compartments on both sides. The powder inlet has multiple left and right powder inlet channels that are spaced apart. The lower end of each left powder inlet channel is connected to the left powder compartment, and the lower end of each right powder inlet channel is connected to the right powder compartment.

[0007] A scraper is fixedly installed at the bottom of the scraper holder and located between the left powder hopper and the right powder hopper;

[0008] A powder-dropping plate is movably disposed at the bottom of the scraper holder. The powder-dropping plate has a through-hole and two powder-dropping holes. The scraper passes through the through-hole, and the two powder-dropping holes are located on both sides of the through-hole.

[0009] The system includes a drive mechanism connected to the powder-discharging plate to drive the powder-discharging plate to move. When the powder-discharging plate moves to the right, one of the powder-discharging holes is aligned with the lower port of the right powder compartment. When the powder-discharging plate moves to the left, the other powder-discharging hole is aligned with the lower port of the left powder compartment.

[0010] Furthermore, the distance between the two powder discharge holes is less than the distance between the left powder compartment and the right powder compartment.

[0011] Furthermore, the lower ends of the left and right powder compartments are both rectangular openings, and the powder discharge hole is a rectangular hole with a width smaller than the width of the lower ends of the left and right powder compartments.

[0012] Furthermore, the width of the clearance hole is greater than the width of the powder discharge hole.

[0013] Furthermore, it also includes two first seals, which are respectively disposed on the edge of the bottom of the scraper holder and on the outer side of the lower port of the left powder inlet channel and the right powder inlet channel, respectively. The upper surface of the powder drop plate is in slidable contact with the two first seals.

[0014] Furthermore, it also includes two second seals, which are respectively disposed at the bottom of the scraper holder. One second seal is located between the scraper and the left powder inlet channel, and the other second seal is located between the scraper and the right powder inlet channel. The upper surface of the powder drop plate is in slidable contact with the two second seals.

[0015] Furthermore, the longitudinal section of the scraper holder is an isosceles trapezoid that is narrow at the top and wide at the bottom.

[0016] Furthermore, the top of the powder inlet is provided with a trapezoidal enlarged opening, and the lower end of the enlarged opening is respectively connected to the upper end of each of the left powder inlet channels and each of the right powder inlet channels.

[0017] Furthermore, the left powder compartment and the right powder compartment have the same shape, both including an upper powder chamber arranged at an incline and a lower powder chamber arranged vertically.

[0018] Furthermore, the driving mechanism includes two cylinders, which are respectively installed at both ends of the scraper frame, and the output ends of the two cylinders face opposite directions and are respectively connected to the powder dropping plate.

[0019] The beneficial effects of the technical solution provided by the embodiments of this utility model are as follows:

[0020] 1. This utility model discloses a powder spreading device. When receiving powder, the two powder-discharging holes on the powder-discharging plate are simultaneously offset from the lower ends of the right and left powder hoppers, allowing the right and left powder hoppers to store powder. When spreading powder from left to right, a drive mechanism drives the powder-discharging plate to move to the right, aligning one powder-discharging hole with the lower end of the right powder hopper. The powder in the right powder hopper falls onto the sintering area of ​​the part and is positioned in front of the scraper. The scraper flattens the powder, completing the next layer of powder spreading. After laser sintering, when returning from right to left to spread powder, the drive mechanism drives the powder-discharging plate to move to the left, aligning one powder-discharging hole with the lower end of the right powder hopper. The lower end of the left powder hopper is aligned, and the powder in the left powder hopper falls into the sintering area of ​​the part and is located in front of the scraper. The scraper flattens the powder, completing the next layer of powder spreading. In this way, by changing the powder drop hole, the powder is ensured to fall in front of the scraper, realizing single-blade bidirectional powder spreading without changing the scraper position. This avoids scraping the surface of the part, reduces the molding risk, and ensures molding quality, balancing powder spreading efficiency and powder spreading quality. Compared with the powder avoidance and lifting method to keep the powder in front of the scraper's return direction, it avoids the powder being contaminated by the smoke and dust from the previous laser sintering process.

[0021] 2. The powder spreading device of this utility model can drive the powder dropping plate to move through the driving mechanism during powder spreading, accurately control the powder spreading area of ​​the powder dropping hole, determine the powder spreading area according to the sintering area of ​​the part, accurately control the boundary of the powder dropping area, and achieve "zero" powder overflow. The powder spreading area can meet the printing requirements, reduce the powder demand in the printing process, and improve the powder utilization rate. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a powder spreading device according to the present invention;

[0023] Figure 2 This is a cross-sectional view of a powder spreading device according to this utility model;

[0024] Figure 3 This is a schematic diagram illustrating the working principle of a bidirectional powder spreading device according to this utility model.

[0025] Figure 4 This is a schematic diagram of the powder-spreading device at the powder receiving position;

[0026] Figure 5 This is a schematic diagram showing the status of the powder spreading device at the left powder spreading position;

[0027] Figure 6 This is a schematic diagram of the powder spreading device at the right powder spreading position.

[0028] In the diagram: 1. Scraper holder; 2. Scraper; 3. Powder discharge plate; 4. Cylinder; 5. Powder inlet; 6. Right powder inlet channel; 7. Left powder inlet channel; 8. Left powder hopper; 9. Right powder hopper; 10. Upper powder chamber; 11. Lower powder chamber; 12. Clearance hole; 13. Powder discharge hole; 14. First seal; 15. Second seal. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be further described below with reference to the accompanying drawings. The following description presents a preferred embodiment of several possible embodiments of this utility model, intended to provide a basic understanding of the utility model, but not intended to identify the key or decisive elements of the utility model or to limit the scope of protection sought.

[0030] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0031] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0032] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures. Also, it should be understood that, for ease of description, the dimensions of the various parts shown in the figures are not drawn to actual scale.

[0033] In the description of this utility model, it should be noted that the circuits, electronic components and modules involved in this utility model are all existing technologies, which can be fully implemented by those skilled in the art, and need not be elaborated upon.

[0034] It should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0035] Please refer to Figure 1 and 2 The present invention provides a powder spreading device for bidirectional powder spreading in the additive manufacturing process, which mainly includes a scraper holder 1, a scraper 2, a powder dropping plate 3, and a driving mechanism.

[0036] The scraper holder 1 has a powder inlet 5 at the top and left powder compartments 8 and right powder compartments 9 on both sides. The powder inlet 5 has multiple left powder inlet channels 7 and right powder inlet channels 6 spaced apart. The lower end of each left powder inlet channel 7 is connected to the left powder compartment 8, and the lower end of each right powder inlet channel 6 is connected to the right powder compartment 9. Powder input through the powder inlet 5 can fall evenly into each left powder inlet channel 7 and each right powder inlet channel 6. Powder entering each left powder inlet channel 7 will flow into the left powder compartment 8, and powder entering each right powder inlet channel 6 will flow into the right powder compartment 9.

[0037] The scraper 2 is fixedly installed at the bottom of the scraper holder 1 and located between the left powder compartment 8 and the right powder compartment 9. The scraper 2 is installed at the bottom of the scraper holder 1 and extends downward, generally positioned at the midpoint between the lower ports of the left powder compartment 8 and the right powder compartment 9.

[0038] The powder-discharging plate 3 is movably mounted at the bottom of the scraper holder 1. The powder-discharging plate 3 has a through-hole 12 and two powder-discharging holes 13. The scraper 2 passes through the through-hole 12, and the two powder-discharging holes 13 are located on either side of the through-hole 12. The width of the through-hole 12 is greater than the width of the scraper 2, thus providing space for the powder-discharging plate 3 to move in front of and behind the scraper 2. Generally, the width of the through-hole 12 is larger than the width of the powder-discharging holes 13.

[0039] The driving mechanism is connected to the powder dropping plate 3 to drive the powder dropping plate 3 to move. When the powder dropping plate 3 moves to the right, one of the powder dropping holes 13 can be aligned with the lower port of the right powder compartment 9. When the powder dropping plate 3 moves to the left, another powder dropping hole 13 can be aligned with the lower port of the left powder compartment 8. When the powder spreading device moves from left to right, the driving mechanism drives the powder dropping plate 3 to move to the right, aligning the powder dropping hole 13 on the right side with the lower port of the right powder hopper 9. The lower port of the right powder hopper 9 is opened, and the powder stored in the right powder hopper 9 falls down, completing the powder spreading from left to right. When the powder spreading device moves from right to left, the driving mechanism drives the powder dropping plate 3 to move to the left, aligning the powder dropping hole 13 on the right side with the lower port of the left powder hopper 8. The lower port of the left powder hopper 8 is opened, and the powder stored in the left powder hopper 8 falls down, completing the powder spreading from right to left. In this way, by changing the working powder dropping hole 13, the powder is ensured to fall in front of the scraper 2, realizing single-blade bidirectional powder spreading without changing the position of the scraper 2.

[0040] In some embodiments, the distance between the two powder discharge holes 13 is smaller than the distance between the left powder compartment 8 and the right powder compartment 9. Thus, a small movement of the powder discharge plate 3 is sufficient to align one powder discharge hole 13 with the lower port of the left powder compartment 8, or to align the other powder discharge hole 13 with the lower port of the other right powder compartment 9.

[0041] Considering that the powder spreading area is generally rectangular, the lower ends of the left powder hopper 8 and the right powder hopper 9 are both rectangular openings, and the powder drop hole 13 is a rectangular hole. The powder spreading device moves along the length of the spreading area, and the powder falling into the lower ends of the left powder hopper 8 and the right powder hopper 9 can cover the spreading area. Furthermore, the width of the powder drop hole 13 can be set to be smaller than the width of the lower ends of the left powder hopper 8 and the right powder hopper 9, so that when the powder drop hole 13 coincides with the lower ends of the left powder hopper 8 and the right powder hopper 9, the powder completely fills the powder drop hole 13, thus allowing the powder to fall evenly.

[0042] The shape of the scraper holder 1 can be flexibly set according to actual application needs. For example, in this embodiment, the longitudinal section of the scraper holder 1 is an isosceles trapezoid that is narrow at the top and wide at the bottom. The scraper holder 1 is provided with powder inlet grooves on both the left and right sides. The opening of the powder inlet grooves is sealed with a cover plate to form the left powder chamber 8 and the right powder chamber 9, so that the left powder chamber 8 and the right powder chamber 9 are arranged approximately symmetrically on the left and right sides of the scraper holder 1.

[0043] As a preferred technical solution, the left powder chamber 8 and the right powder chamber 9 have the same shape, each including an upper powder chamber 10 inclined at the top and a lower powder chamber 11 vertically arranged at the bottom. The upper powder chamber 10 is used to connect to the powder inlet 5 to introduce powder, and the lower powder chamber 11 is used to output the stored powder downwards.

[0044] To facilitate powder entry into the powder inlet 5 during powder collection, the top of the powder inlet 5 is provided with a trapezoidal enlarged opening, the lower end of which is connected to the upper ends of each of the left powder inlet channels 7 and each of the right powder inlet channels 6. The powder first enters the enlarged opening, and then disperses from the bottom of the enlarged opening into each of the left powder inlet channels 7 and each of the right powder inlet channels 6.

[0045] The drive mechanism can be flexibly selected from various linear motion drive mechanisms according to the actual application scenario, and can drive the powder-dropping plate 3 to move along the width direction of the scraper frame 1. In this embodiment, the drive mechanism includes two cylinders 4, which are respectively installed at both ends of the scraper frame 1. The output ends of the two cylinders 4 face opposite directions and are respectively connected to the powder-dropping plate 3. Here, the output ends of the two cylinders 4 are to the left or right, which can drive the powder-dropping plate 3 to move to the left or right respectively.

[0046] Furthermore, considering that the movement of the powder-discharging plate 3 may cause powder leakage at the contact points between the powder-discharging hole and the lower ports of the left powder chamber 8 and the right powder chamber 9, the powder-spreading device of this utility model also includes two first sealing elements 14. The first sealing elements 14 are density pads. The two first sealing elements 14 are respectively disposed on the bottom edge of the scraper frame 1. The two first sealing elements 14 are respectively disposed on the outer side of the lower ports of the left powder inlet channel 7 and the right powder inlet channel 6. The upper surface of the powder-discharging plate 3 is in slidable contact with the two first sealing elements 14. The first sealing elements 14 can prevent powder from leaking out from the gaps between the powder-discharging plate 3 and the scraper frame 1 when the powder-discharging plate 3 moves.

[0047] Furthermore, to further prevent powder leakage, the powder spreading device of this utility model also includes two second sealing elements 15. Each second sealing element 15 is a density pad, and the two second sealing elements 15 are respectively disposed at the bottom of the scraper holder 1. One second sealing element 15 is located between the scraper 2 and the left powder inlet channel 7, and the other second sealing element 15 is located between the scraper 2 and the right powder inlet channel 6. The upper surface of the powder dropping plate 3 is in slidable contact with the two second sealing elements 15. The second sealing elements 15 can prevent powder from leaking out from the contact surface between the powder dropping plate 3 and the scraper holder 1 near the clearance hole 12.

[0048] like Figure 3-6 As shown, the process of bidirectional powder spreading on the forming base by the powder spreading device of this utility model is as follows:

[0049] The forming base is generally divided into four areas: powder receiving area I, powder spreading area II, forming area III, and part sintering area IV. Powder spreading area II is the middle area between the left and right powder spreading positions. Forming area III is located inside powder spreading area II. Part sintering area IV is located inside forming area III. Powder receiving area I is located on one side of powder spreading area II and there is a certain distance between them.

[0050] When the powder spreading device is in the powder receiving position of the powder receiving area I, the driving mechanism drives the powder dropping plate 3 to the middle position of the avoidance hole 12, so that the two powder dropping holes 13 on the powder dropping plate 3 are simultaneously offset from the lower ports of the right powder bin 9 and the left powder bin 8, so that the lower ends of the right powder bin 9 and the left powder bin 8 are closed to store powder.

[0051] Then, when the powder spreading device moves forward from left to right, the powder spreading device first moves at high speed to the left powder spreading position AB, and drives the powder dropping plate 3 to move to the right through the drive mechanism so that a powder dropping hole 13 is aligned with the lower port of the right powder bin 9. The powder spreading device continues to move at high speed to the left boundary E of the part sintering area IV, then changes to low speed and continues to move to the right boundary F of the part sintering area IV. The powder spreading device then changes to high speed and continues to move to the right powder spreading position CD. The powder in the right powder bin 9 falls into the part sintering area and is located in front of the scraper 2. The scraper 2 scrapes the powder flat, completing the next layer of powder spreading.

[0052] After laser sintering, when returning to the powder spreading position from right to left, the powder dropping plate 3 is driven to move to the left by the drive mechanism so that a powder dropping hole 13 is aligned with the lower port of the left powder hopper 8. The powder spreading device moves at high speed to the right boundary F of the part sintering area IV, then changes to low speed and continues to move to the left boundary E of the part sintering area IV. The powder spreading device then changes to high speed and continues to move to the left powder spreading position. The powder in the left powder hopper 8 falls into the part sintering area and is located in front of the scraper 2. The scraper 2 scrapes the powder flat, completing the previous layer of powder spreading.

[0053] Finally, the powder-dropping plate 3 is driven by the drive mechanism to be in the middle position of the avoidance hole 12, so that the two powder-dropping holes 13 on the powder-dropping plate 3 are simultaneously offset from the lower ports of the right powder chamber 9 and the left powder chamber 8. The powder-spreading device continues to move at high speed to the powder-dropping position, completing the entire single-blade bidirectional powder-spreading action.

[0054] In this document, the directional terms such as front, back, top, and bottom are defined based on the position of the components in the accompanying drawings and their relative positions to each other, solely for the purpose of clarity and convenience in expressing the technical solution. It should be understood that these are relative concepts and can vary depending on different methods of use and placement; the use of these directional terms should not limit the scope of protection claimed in this application.

[0055] Where there is no conflict, the embodiments and features described above can be combined with each other. The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A powder spreading device, characterized in that, include: The scraper holder has a powder inlet at the top and left and right powder compartments on both sides. The powder inlet has multiple left and right powder inlet channels that are spaced apart. The lower end of each left powder inlet channel is connected to the left powder compartment, and the lower end of each right powder inlet channel is connected to the right powder compartment. A scraper is fixedly installed at the bottom of the scraper holder and located between the left powder hopper and the right powder hopper; A powder-dropping plate is movably disposed at the bottom of the scraper holder. The powder-dropping plate has a through-hole and two powder-dropping holes. The scraper passes through the through-hole, and the two powder-dropping holes are located on both sides of the through-hole. The system includes a drive mechanism connected to the powder-discharging plate to drive the powder-discharging plate to move. When the powder-discharging plate moves to the right, one of the powder-discharging holes is aligned with the lower port of the right powder compartment. When the powder-discharging plate moves to the left, the other powder-discharging hole is aligned with the lower port of the left powder compartment.

2. The powder spreading device as described in claim 1, characterized in that: The distance between the two powder discharge holes is less than the distance between the left powder compartment and the right powder compartment.

3. The powder spreading device as described in claim 1, characterized in that: The lower ends of the left and right powder compartments are both rectangular openings, and the powder discharge hole is a rectangular hole with a width smaller than the width of the lower ends of the left and right powder compartments.

4. The powder spreading device as described in claim 1, characterized in that: The width of the clearance hole is greater than the width of the powder discharge hole.

5. The powder spreading device as described in claim 1, characterized in that: It also includes two first seals, which are respectively disposed on the edge of the bottom of the scraper holder and on the outer side of the lower port of the left powder inlet channel and the right powder inlet channel. The upper surface of the powder drop plate is in slidable contact with the two first seals.

6. The powder spreading device as described in claim 1, characterized in that: It also includes two second seals, which are respectively disposed at the bottom of the scraper holder. One second seal is located between the scraper and the left powder inlet channel, and the other second seal is located between the scraper and the right powder inlet channel. The upper surface of the powder drop plate is in slidable contact with the two second seals.

7. The powder spreading device as described in claim 1, characterized in that: The longitudinal section of the scraper holder is an isosceles trapezoid that is narrow at the top and wide at the bottom.

8. The powder spreading device as described in claim 1, characterized in that: The top of the powder inlet is provided with a trapezoidal enlarged opening, and the lower end of the enlarged opening is connected to the upper end of each of the left powder inlet channels and each of the right powder inlet channels.

9. The powder spreading device as described in claim 1, characterized in that: The left and right powder compartments have the same shape, each including an upper powder chamber that is inclined at the top and a lower powder chamber that is vertically arranged at the bottom.

10. The powder spreading device as described in claim 1, characterized in that: The drive mechanism includes two cylinders, which are respectively installed at both ends of the scraper frame. The output ends of the two cylinders face opposite directions and are respectively connected to the powder dropping plate.

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