阅读说明：本技术 挤出沉积成形的熔体流量控制方法及装置 (Melt flow control method and device for extrusion deposition forming ) 是由 马明 胡志刚 张可维 李彬 陈艳 蒋亚军 张鸿海 于 2020-12-24 设计创作，主要内容包括：本发明提供一种挤出沉积成形的熔体流量控制装置,包括容器,容器用于盛装熔融的熔体；容器的底端形成有通孔,通孔上安装有喷嘴；喷嘴的下方间隔预设距离设置有基板,基板与运动平台连接；活塞杆,活塞杆设置于容器内,活塞杆包括连杆和设置于连杆底端的挤压头,挤压头用于打开或关闭通孔,挤压头呈阶梯型设置。容器用于盛装熔融的熔体,熔体经过容器底端的通孔和安装于通孔上的喷嘴落到基板上,冷却后形成金属固体；基板三维运动平台连接进而获得需要的零件形状。该挤出沉积成形的熔体流量控制装置具有结构简单、制作成本低,能够调整零件制作精度的优点。本发明还提供一种挤出沉积成形的熔体流量控制方法。(The invention provides a melt flow control device for extrusion deposition molding, which comprises a container, a control device and a control device, wherein the container is used for containing a molten melt; a through hole is formed at the bottom end of the container, and a nozzle is arranged on the through hole; a substrate is arranged below the nozzle at a preset distance and connected with the motion platform; the piston rod, the piston rod sets up in the container, and the piston rod includes the connecting rod and sets up in the extrusion head of connecting rod bottom, and the extrusion head is used for opening or closes the through-hole, and the extrusion head is the notch cuttype setting. The container is used for containing molten melt, the melt falls onto the substrate through the through hole at the bottom end of the container and the nozzle arranged on the through hole, and a metal solid is formed after cooling; the substrate three-dimensional motion platform is connected to obtain the required part shape. The melt flow control device for extrusion deposition forming has the advantages of simple structure, low manufacturing cost and capability of adjusting the manufacturing precision of parts. The invention also provides a melt flow control method for extrusion deposition forming.)

1. An extrusion deposition formed melt flow control device, comprising:

a vessel for holding a molten melt;

a through hole is formed at the bottom end of the container, and a nozzle is arranged on the through hole;

a substrate is arranged below the nozzle at a preset distance and connected with the motion platform;

the piston rod, the piston rod set up in the container, the piston rod include the connecting rod with set up in the extrusion head of connecting rod bottom, the extrusion head is used for opening or closing the through-hole, the extrusion head is the notch cuttype setting.

2. An extrusion deposition melt flow control apparatus according to claim 1, wherein the cross-section of the extrusion head decreases in size from the connecting rod to an end remote from the connecting rod.

3. The extrusion deposition modeling melt flow control apparatus of claim 1 wherein said extrusion head is a cylindrical extrusion head.

4. The extrusion deposition melt flow control apparatus of claim 3, wherein the extrusion head comprises a first step, a second step and a third step arranged in sequence, the first step is connected with the connecting rod, the diameter of the cross-section circle of the first step is larger than that of the through hole, and the diameter of the cross-section circle of the second step and that of the third step are smaller than that of the through hole.

5. The extrusion deposition melt flow control apparatus of claim 4, wherein the extrusion head further comprises a fourth step disposed on a side of the third step that is opposite the second step.

6. The extrusion deposition modeling melt flow control device of claim 1 further comprising a pressurized bottle, wherein the pressurized bottle is connected to the cavity of the container through a gas pipe, and the pressurized bottle is further provided with a pressure regulating valve.

7. The extrusion deposition modeling melt flow control apparatus of claim 1 wherein the vessel is a crucible and the melt is a metal melt.

8. The extrusion deposition melt flow control apparatus of claim 7, wherein the substrate is a metal plate having a melting point higher than a melting point of the metal melt.

9. A melt flow control method for extrusion deposition modeling, wherein the melt flow control method for extrusion deposition modeling employs the melt flow control device for extrusion deposition modeling of any one of claims 1 to 8, and the melt flow control method for extrusion deposition modeling comprises the following steps:

adjusting the pressurization bottle to make the air pressure in the container reach a preset air pressure;

adjusting the distance between the nozzle and the substrate;

the piston rod is driven to move upwards to a preset position so as to open the through hole;

and driving the substrate to move according to the preset movement speed and the preset movement track.

10. The extrusion deposition modeling melt flow control method according to claim 9, wherein the step of adjusting the pressurized bottle to make the air pressure in the container to a preset air pressure further comprises:

the vessel is heated such that the metallic material within the vessel is heated to form a metal melt.

Technical Field

The invention relates to the field of melt flow control devices, in particular to a melt flow control method and device for extrusion deposition forming.

Background

Additive manufacturing is a material accumulation forming technology from bottom to top, which is a technology that is driven by a Three-Dimensional Computer-Aided Design (3D CAD) digital model, does not need any die assistance, and directly forms a Three-Dimensional entity through point-by-point and layer-by-layer accumulation of materials. To date, a variety of mature metal additive manufacturing techniques have been developed, typically: selective Laser Sintering (SLS), Laser Engineered Net Shaping (LENS), Electron Beam Melting (EBM), and Selective Laser cladding (SLM), among others. However, the manufacturing equipment is expensive, and the precision of the parts is not well controlled.

In view of the above, there is a need for a novel method and apparatus for controlling melt flow in extrusion deposition molding, which solves or at least alleviates the above technical drawbacks.

Disclosure of Invention

The invention mainly aims to provide a melt flow control method and a melt flow control device for extrusion deposition molding, and aims to solve the technical problems that in the prior art, part manufacturing equipment is expensive and part manufacturing precision is not easy to control due to the adoption of additive manufacturing.

To achieve the above object, according to one aspect of the present invention, there is provided a melt flow control device for extrusion deposition molding, comprising:

a vessel for holding a molten melt;

a through hole is formed at the bottom end of the container, and a nozzle is arranged on the through hole;

a substrate is arranged below the nozzle at a preset distance and connected with the motion platform;

the piston rod, the piston rod set up in the container, the piston rod include the connecting rod with set up in the extrusion head of connecting rod bottom, the extrusion head is used for opening or closing the through-hole, the extrusion head is the notch cuttype setting.

Optionally, the size of the cross-section of the extrusion head decreases from the connecting rod to the end remote from the connecting rod.

Optionally, the extrusion head is a cylindrical extrusion head.

Optionally, the extrusion head includes first ladder, second ladder and the third ladder that sets gradually, first ladder with the connecting rod is connected, the cross-section circle diameter of first ladder is greater than the diameter of through-hole, the cross-section circle diameter of second ladder with the third ladder all is less than the diameter of through-hole.

Optionally, the base extrusion head further includes a fourth step, and the fourth step is disposed on one side of the third step, which is backed to the second step.

Optionally, the extrusion deposition-formed melt flow control device further comprises a pressurizing bottle, the pressurizing bottle is communicated with the cavity of the container through an air pipe, and a pressure regulating valve is further arranged on the pressurizing bottle.

Optionally, the container is a crucible and the melt is a metal melt.

Optionally, the substrate is a metal plate, and the melting point of the metal plate is higher than that of the metal melt.

According to another aspect of the present invention, the present invention further provides a melt flow control method for extrusion deposition modeling, which employs the above melt flow control device for extrusion deposition modeling, the melt flow control method for extrusion deposition modeling comprising the following steps:

adjusting the pressurization bottle to make the air pressure in the container reach a preset air pressure;

adjusting the distance between the nozzle and the substrate;

the piston rod is driven to move upwards to a preset position so as to open the through hole;

and driving the substrate to move according to the preset movement speed and the preset movement track.

Optionally, before the step of adjusting the pressurized bottle to make the air pressure in the container reach the preset air pressure, the method further comprises:

the vessel is heated such that the metallic material within the vessel is heated to form a metal melt.

In the technical scheme of the invention, the melt flow control device for extrusion deposition forming comprises a container, wherein the container is used for containing molten melt; a through hole is formed at the bottom end of the container, and a nozzle is arranged on the through hole; a substrate is arranged below the nozzle at a preset distance and connected with the motion platform; the piston rod, the piston rod sets up in the container, and the piston rod includes the connecting rod and sets up in the extrusion head of connecting rod bottom, and the extrusion head is used for opening or closes the through-hole, and the extrusion head is the notch cuttype setting. In the scheme, the container is used for containing the molten melt, the melt falls onto the substrate through the through hole at the bottom end of the container and the nozzle arranged on the through hole, and a metal solid is formed after cooling; the base plate is connected with the motion platform, and specifically, the motion platform is a three-dimensional motion platform, and can drive the base plate to move in X, Y, Z three directions, thereby obtaining the required part shape. The extrusion head of the piston rod is used for opening or closing the through hole, specifically, when the piston rod moves upwards, the through hole is opened, and the melt can fall onto the substrate through the through hole and the nozzle to form a deposition body; when the piston rod moves downwards to the preset position, the through hole is closed, and metal deposition cannot be carried out. The embodiment realizes effective metallurgical bonding between deposition layers by extruding melt to deposit on the substrate, and drives the substrate to move on a three-dimensional line by the moving platform so as to realize three-dimensional manufacturing. The basic process of manufacturing the three-dimensional solid part based on the metal melting extrusion deposition forming principle is to stack lines into faces, and then stack the faces layer by layer to finally obtain the part, so that the melt line is a basic deposition unit, the precision of the melt line is an important factor restricting the melt melting extrusion deposition forming process and the application thereof, and the melt line precision can be obviously influenced by melt flow control. Therefore, the extrusion head is arranged in a step shape, the flow of the melt can be controlled through the position of the extrusion head extending into the through hole, the precision of the melt line is further controlled, and the precision of the part is finally controlled. Compared with the prior art, the invention has the advantages of simple structure, low manufacturing cost and capability of adjusting the manufacturing precision of parts.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic view of an extrusion head closing a through hole of a melt flow control device for extrusion deposition molding according to an embodiment of the present invention;

FIG. 2 is a schematic view of an extrusion head of an extrusion deposition apparatus of an embodiment of the present invention not extending into a through-hole;

FIG. 3 is a schematic view of an extrusion deposition shaped melt flow control device extrusion head portion extending into a through hole in accordance with an embodiment of the present invention;

FIG. 4 is an enlarged view of FIG. 3 at A;

FIG. 5 is another enlarged view of FIG. 3 at A (labeled differently than FIG. 4);

fig. 6 is a schematic view of a cross section of the extrusion head and the through-hole.

The reference numbers illustrate:

1. a crucible; 11. a through hole; 2. a piston rod; 21. a connecting rod; 22. an extrusion head; 221. a first step; 222. a second step; 223. a third step; 224. a fourth step; 3. a nozzle; 4. a substrate; 5. melting the materials; 6. depositing the body.

The implementation, functional features and advantages of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

It should be noted that all the directional indicators (such as the upper and lower … …) in the embodiment of the present invention are only used to explain the relative position relationship, movement, etc. of the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

Moreover, the technical solutions in the embodiments of the present invention may be combined with each other, but it is necessary to be able to be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent, and is not within the protection scope of the present invention.

Referring to fig. 1-5, according to one aspect of the present invention, there is provided a melt flow control device for extrusion deposition molding, comprising:

a container for holding a molten melt;

a through hole is formed at the bottom end of the container, and a nozzle is arranged on the through hole;

a substrate is arranged below the nozzle at a preset distance and connected with the motion platform;

the piston rod, the piston rod sets up in the container, and the piston rod includes the connecting rod and sets up in the extrusion head of connecting rod bottom, and the extrusion head is used for opening or closes the through-hole, and the extrusion head is the notch cuttype setting.

In the above embodiment, the container is used for containing the molten melt, the melt falls onto the substrate through the through hole at the bottom end of the container and the nozzle installed on the through hole, and the metal solid is formed after cooling; the base plate is connected with the motion platform, and specifically, the motion platform is a three-dimensional motion platform, and can drive the base plate to move in X, Y, Z three directions, thereby obtaining the required part shape. The extrusion head of the piston rod is used for opening or closing the through hole, specifically, when the piston rod moves upwards, the through hole is opened, and the melt can fall onto the substrate through the through hole and the nozzle to form a deposition body; when the piston rod moves downwards to the preset position, the through hole is closed, and metal deposition cannot be carried out. The embodiment realizes effective metallurgical bonding between deposition layers by extruding melt to deposit on the substrate, and drives the substrate to move on a three-dimensional line by the moving platform so as to realize three-dimensional manufacturing. The basic process of manufacturing the three-dimensional solid part based on the metal melting extrusion deposition forming principle is to stack lines into faces, and then stack the faces layer by layer to finally obtain the part, so that the melt line is a basic deposition unit, the precision of the melt line is an important factor restricting the melt melting extrusion deposition forming process and the application thereof, and the melt line precision can be obviously influenced by melt flow control. Therefore, the extrusion head is arranged in a step shape, the flow of the melt can be controlled through the position of the extrusion head extending into the through hole, the precision of the melt line is further controlled, and the precision of the part is finally controlled. Compared with the prior art, the embodiment has the advantages of simple structure, low manufacturing cost and capability of adjusting the manufacturing precision of parts. Specifically, the melt may be a metal melt, and the corresponding melt line is a metal wire.

Further, the cross-sectional dimension of the extrusion head decreases from the connecting rod to the end remote from the connecting rod. Further, the extrusion head is a cylindrical extrusion head. The size of the extrusion head cross-section affects the flow of the melt and thus the melt line accuracy. The shape of the extrusion head is not particularly limited in this embodiment, and the extrusion head is configured to be cylindrical, the formed gap is annular, and the melt flows relatively uniformly in the gap formed by the two cylindrical surfaces.

Further, the container is a crucible, and the melt is a metal melt. The melting point of the crucible is high, the metal material can be put into the crucible to be heated to obtain metal melt, and the melt formed after the metal is heated can also be poured into the crucible.

Further, the substrate is a metal plate, and the melting point of the metal plate is higher than that of the metal melt. The substrate is also made of a metal material, but the material is different from the metal material contained in the crucible, and those skilled in the art can understand that the melting point of the substrate should be higher than that of the metal melt to prevent the substrate from melting.

Furthermore, the melt flow control device for extrusion deposition forming further comprises a pressurizing bottle, the pressurizing bottle is communicated with the cavity of the container through an air pipe, and a pressure regulating valve is further arranged on the pressurizing bottle. The gas pressure P may be applied artificially to the inside of the cavity of the crucible. The source of the gas pressure may be an inert high pressure gas source, such as high purity nitrogen. High-purity nitrogen is stored in a steel cylinder, the nitrogen is introduced into the crucible cavity of the metal melt by using a gas valve and a gas pipe, and the pressure P can be controlled by a pressure reducing valve and a tight pressure regulating valve. Of course, other inert high pressure gases may be used.

Further, the extrusion head includes first ladder, second ladder and the third ladder that sets gradually, and first ladder is connected with the connecting rod, and the cross-section circle diameter of first ladder is greater than the diameter of through-hole, and the cross-section circle diameter of second ladder and third ladder all is less than the diameter of through-hole, and the base extrusion head still includes the fourth ladder, and the fourth ladder sets up in the third ladder and leans against one side of second ladder.

For the purpose of clearly illustrating the embodiments of the present invention, reference will now be made to the accompanying drawings.

Referring to fig. 1 to 3, the melt flow control device for metal melt extrusion deposition modeling additive manufacturing according to the present invention includes: piston rod, crucible, nozzle and base plate. The nozzle is arranged in the through hole of the crucible, and the substrate is fixed on the three-dimensional motion platform. The formed metal material in the crucible is heated to melt and form a metal melt. And depositing and cooling the metal melt on the surface of the substrate to obtain a deposited body.

Referring to FIGS. 3 to 5, the through-hole of the crucible is a cylindrical hole having a diameter of phi_b. On the extrusion head, the cross section of each part of the extrusion head is circular, each step is a cylinder, and the diameters of the first step, the second step, the third step and the fourth step are phi respectively_S、φ_t1、φ_t2And phi_t3. Wherein phi is_SDiameter phi of through hole larger than crucible_b，φ_t1、φ_t2And phi_t3Are all smaller than the diameter phi of the through hole of the crucible_b. The piston rod is coaxial with the crucible through hole, the drive mechanism drives the piston rod to move downwards, and after the stepped part of the extrusion head penetrates into the crucible through hole, a cylindrical annular gap G is formed between the wall of the crucible through hole and the side wall of the stepped lower end of the piston rod. When the downward moving distance of the piston rod is changed, the length of the stepped part at the lower end of the piston rod extending into the crucible through hole is correspondingly changed, and the unilateral radial width H or the axial length L of the cylindrical annular gap is changed accordingly. The flow of the metal melt at the outlet of the nozzle can be changed by independently changing the value of H or L, so that the precision of the part is controlled.

Specifically, the mass of the molten metal flowing out of the nozzle is equal to the mass of the deposited body according to the conservation of mass, and when the substrate moves linearly at a constant velocity and the deposited body is a uniform metal wire, there is a phenomenon that

q_v＝A_wv_s (1)

In the above formula (1), v_sIs the speed of movement of the substrate, A_wIs the cross-sectional area of the wire when v is_sWhile remaining unchanged, q_vThe smaller, A_wThe smaller, i.e. the thinner the metal wire obtained, the higher the precision of the part obtained for the three-dimensional entity in which the thinner metal wires are stacked.

And the flow calculation formula in the gap formed by the two cylindrical surfaces is as follows:

in the above formula (2), q_vIs the flow in the annular gap, i.e. q in equation (1)_v. The physical quantities represented by H and L are the same as those shown in FIG. 4, and the physical quantities represented by d are the same as those shown by φ in FIG. 5_t1、φ_t2、φ_t3And so, FIG. 6 shows schematic diagrams of d and H.

As can be seen from equation (2), H and L are related to q_vThe influence degree of (A) is different, H is a cubic power, and the influence effect is more remarkable than that of L. In addition, the value of H is not continuously changed, but the value of L may be continuously changed as the piston rod 1 is moved in the vertical direction. Adjusting the value of H, q_vChange faster, adjust q of L_vValue, change slower for q_vThe value of H is adjusted for coarse adjustment and the value of L is adjusted for fine adjustment. Therefore, the flow rate q can be adjusted by adjusting the distance of the extrusion head extending into the through hole and further adjusting the values of H and L_vThe accuracy of the wire is varied and adjusted to adjust the accuracy of the resulting part.

Referring to FIG. 2, when the molten metal extrusion deposition forming system for the piston rod is not in operation, the diameter of the lower end of the piston rod is phi_SPart is close to the bottom of the crucible because of phi_SDiameter phi of through hole larger than crucible_bThe through hole of the crucible is closed, and the metal melt cannot flow out. When the piston rod metal melt extrusion deposition forming system starts to work, the driving mechanism drives the piston rod to move upwards for a certain distance, and the metal melt flows through the through hole of the crucible and flows out from the outlet of the nozzle.

According to another aspect of the present invention, the present invention further provides a melt flow control method for extrusion deposition modeling, which employs the above melt flow control device for extrusion deposition modeling, the melt flow control method for extrusion deposition modeling comprising the following steps:

adjusting the pressurizing bottle to enable the air pressure in the container to reach a preset air pressure;

adjusting the distance between the nozzle and the substrate;

the piston rod is driven to move upwards to a preset position so as to open the through hole;

and driving the substrate to move according to the preset movement speed and the preset movement track.

In the above embodiment, under atmospheric pressure P's drive, can control the thickness of sedimentary deposit through adjusting the distance G between nozzle and the base plate in advance, can control the width of sedimentary deposit through the velocity of motion of adjusting the base plate, according to actual need, adjust the length that the extrusion head stretched into the crucible, can control the flow of metal melt in nozzle department, and then control accuracy. Referring to fig. 1 and 2, specifically, the piston rod moves upwards to change the through hole at the bottom of the crucible from a closed state to an open state, the metal melt flows out of the nozzle and falls on the surface of the substrate under other driving, meanwhile, the three-dimensional moving platform drives the substrate to move at a preset moving speed and a preset moving track, the metal melt is deposited and cooled on the surface of the substrate, and a metal deposition body is formed between the nozzle and the substrate. And the thickness of the metal layer deposition body is increased layer by layer along with the movement of the substrate, and finally the part is formed. Referring to fig. 2, after the extrusion deposition forming operation is completed, the piston rod moves downwards to completely seal the through hole of the crucible. And after the metal deposition body is completely cooled, separating the substrate from the metal deposition body to finally obtain the required part.

Further, before the step of adjusting the pressure bottle to make the air pressure in the container reach the preset air pressure, the method further comprises the following steps:

the vessel is heated such that the metallic material within the vessel is heated to form a metal melt. According to actual needs, a metal material is added into the crucible and heated to obtain a metal melt, or the molten metal melt is directly added into the crucible.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the technical spirit of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.