Piston type slurry extrusion assembly and continuous extrusion mechanism

Abstract

The invention relates to a piston type slurry extrusion assembly and a continuous extrusion mechanism. The extrusion assembly comprises a feeding channel and a discharging channel, wherein the feeding channel is formed by connecting a feeding one-way valve, a lead screw guide pipe push rod and an annular piston in series, and the discharging channel is formed by a discharging one-way valve connected with a charging barrel. A lead screw nut of a driving motor rotates to enable a lead screw guide pipe push rod and an annular piston to do linear motion in a charging barrel, and slurry enters the charging barrel through a feeding channel and is extruded out of a discharging channel; the continuous extrusion mechanism is composed of two piston type slurry extrusion assemblies, a feeding pipeline, a discharging pipeline and a storage tank, and continuous supply of slurry is achieved by controlling the two piston type slurry extrusion assemblies to work alternately. According to the continuous slurry extrusion mechanism, a piston push rod is directly pushed by a driving motor, the structure is simple, and the slurry conveying control precision is high; slurry enters the charging barrel through the center hole of the annular piston and is extruded out of the discharging pipeline according to the first-in first-out sequence, and local retention of the high-viscosity slurry in the charging barrel is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing and dispensing, and in particular to a piston-type slurry extrusion component and a continuous extrusion mechanism for continuous delivery of high-viscosity slurry. Background Art

[0002] In the prior art, slurry material transportation used in slurry 3D printing or dispensing is usually carried out by pneumatic drive, screw drive and piston drive. The pneumatic driven feeding mechanism uses an electric valve to control the gas pressure to push the slurry out of the barrel. Due to the influence of different viscosities and materials of the slurry, it is difficult to implement high-precision control of pneumatic driven feeding. At the same time, due to the volume limitation of the barrel, the barrel needs to be replaced frequently when a large amount of slurry needs to be transported; the screw driven feeding mechanism relies on the mobile sealing cavity formed by the rotation of the screw in the bushing to drive the slurry to extrude, which is suitable for continuous transportation of a large amount of slurry, but due to the processing gap between the screw and the bushing, there will be a small amount of reflux of the slurry during transportation. To achieve high-precision control, high-precision screw and bushing processing is required, and the cost is relatively high; the piston driven feeding mechanism relies on the piston to change the volume in the barrel to extrude the slurry, which is suitable for precise control of slurry output, but due to the volume limitation of the barrel, the barrel still needs to be replaced frequently when a large amount of slurry is transported.

[0003] In order to solve the problem of continuously conveying a large amount of slurry with a piston, the existing technology usually adopts a structure in which a feed check valve and a discharge check valve are connected by a three-way connection at the barrel outlet, and the slurry in the barrel is extruded and replenished by the reciprocating motion of the piston. However, when conveying high-viscosity slurry with weak fluidity, due to the gap between the piston end face and the barrel outlet, some air is retained on the piston end face to form cavitation, which is difficult to remove when the barrel sucks and extrudes the slurry. The compressibility of the cavitation will affect the control accuracy of the slurry extrusion. At the same time, a small amount of slurry entering the gap area is also difficult to be discharged from the barrel through the piston, resulting in the long-term residence of some slurry. When conveying high-viscosity slurry with time requirements, the barrel needs to be regularly maintained and cleaned, which increases the maintenance cost and limits the selection of conveying materials.

[0004] In summary, the existing technology for high-precision continuous delivery of high-viscosity slurries is still insufficient. Therefore, it is necessary to provide a slurry extrusion assembly and a continuous extrusion mechanism to overcome the defects of the related technology. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a piston-type slurry extrusion component and a continuous extrusion mechanism, which can convey high-viscosity slurry continuously and uninterruptedly with high precision.

[0006] In order to solve the above technical problems, the present invention provides a piston-type slurry extrusion assembly, including a feed check valve, a screw guide push rod, an annular piston, a barrel, a discharge check valve, a drive motor and a stop sleeve, characterized in that: the feed check valve, the screw guide push rod and the annular piston are connected in series to form a feed channel; the discharge check valve is connected to the barrel outlet to form a discharge channel; the barrel is mechanically fixed to the outside of the drive motor housing, and the annular piston is arranged in the barrel; the drive motor shaft is a screw nut; the outer surface of the screw guide push rod is provided with a threaded nut that is connected to the screw in the drive motor The screw nut is matched with a spiral groove and at least one milled flat surface or a key groove running through the two end surfaces along the axial side; the anti-rotation sliding sleeve is coaxially fixed to the outside of the driving motor housing with the screw nut, and is provided with a sliding surface matching the outer contour of the cross-section of the screw guide push rod, and the sliding surface is nested in the outer surface of the screw guide push rod, and is arranged to prevent the screw guide push rod from rotating and provide a guide for the linear sliding of the screw guide push rod; the screw nut of the driving motor is nested in the outer surface of the screw guide push rod, and the screw guide push rod and the annular piston are driven to perform linear reciprocating motion in the barrel through the rotation of the screw nut.

[0007] Furthermore, the driving motor is a stepping motor or a servo motor.

[0008] Optionally, the feed one-way valve and the discharge one-way valve are electric valves. When feeding, the feed electric valve is opened and the discharge electric valve is closed. When discharging, the discharge electric valve is opened and the feed electric valve is closed.

[0009] Optionally, a limit switch is provided in the piston-type slurry extrusion assembly for detecting a limited position of the linear motion of the spline screw guide rod.

[0010] The present invention also provides a piston-type slurry continuous extrusion mechanism, comprising a first piston-type slurry extrusion component, a second piston-type slurry extrusion component, a feed pipeline, a discharge pipeline, a three-way pipeline, a storage tank and a controller, wherein the feed pipeline is connected between the feed one-way valves of the first piston-type slurry extrusion component and the second piston-type slurry extrusion component and the discharge port of the storage tank; the discharge one-way valves of the first piston-type slurry extrusion component and the second piston-type slurry extrusion component are connected to the first and second ends of the three-way pipeline, and the discharge pipeline is connected to the third end of the three-way pipeline; the controller is electrically connected to the piston-type slurry extrusion component, and is used to drive the first piston-type slurry extrusion component and the second piston-type slurry extrusion component to move alternately so that the slurry is continuously extruded through the discharge pipeline without interruption.

[0011] Optionally, the storage tank is a pressurized storage tank, and a gas source is configured to maintain the pressure in the storage tank.

[0012] Due to the adoption of the above technical scheme, compared with the existing technology, the present invention has the following advantages: 1) The piston-driven feeding mechanism is used to extrude the slurry, and the output can be accurately controlled. At the same time, it is applicable to a wide viscosity range; 2) The slurry is fed from the piston push rod, and the slurry enters the barrel through the center hole of the annular piston. When extruding and conveying high-viscosity slurry with weak fluidity, the slurry is extruded from the discharge pipeline in a first-in-first-out order, thereby avoiding the local retention of the slurry in the barrel; 3) The drive motor is used to directly drive the screw piston push rod, which simplifies the component structure, is easy to assemble and manufacture, and reduces the manufacturing cost; 4) The double-piston extrusion component is used for alternating extrusion, which can realize continuous and uninterrupted conveying of the slurry and has high extrusion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the cross-sectional structure of a piston-type slurry extrusion component.

[0014] Figure 2 It is a structural schematic diagram of a piston type slurry extrusion assembly anti-rotation sliding sleeve and a lead screw guide rod.

[0015] Figure 3 It is a schematic diagram of the principle of a piston-type slurry extrusion component using an electric valve.

[0016] Figure 4 It is a schematic diagram of the principle of the piston-type slurry continuous extrusion mechanism.

[0017] Figure 5 It is a schematic diagram of a piston-type continuous slurry extruder using a pressurized storage tank and an electric valve.

[0018] In the figure: 100, piston type slurry extrusion assembly; 10, feed channel; 11, feed non-return valve; 12, screw guide push rod; 13, annular piston; 14, spiral groove; 15, milled flat surface; 16 keyway; 20, barrel; 21, discharge channel; 22, discharge non-return valve; 30, drive motor; 31, motor rotor; 32 screw nut; 33, motor housing; 40, anti-rotation sleeve; 41, sliding surface; 50, limit switch; 51, limit part; 60, feed pipeline; 61, discharge pipeline; 62, three-way pipeline; 70, storage tank; 71, air pressure source; 80, electronic control device; 200, first piston type slurry extrusion assembly; 300, second piston type slurry extrusion assembly. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation examples: Figure 1 , Figure 2 As shown, a piston-type slurry extrusion assembly 100 according to the present invention includes a feed channel 10, a barrel 20, a discharge channel 21, a drive motor 30 and a stop sleeve 40.

[0020] The feed channel 10 is composed of a feed check valve 11, a screw guide push rod 12, and an annular piston 13 connected in series. The discharge channel 21 is composed of a barrel 20 outlet connected to a discharge check valve 22. The barrel 20 is fixed to the outside of a drive motor housing 33. The annular piston 13 is arranged in the barrel 20. The rotating shaft of the motor rotor 31 of the drive motor 30 is a screw nut 32. The screw nut 32 of the drive motor 30 is nested in the outer surface of the screw guide push rod 12. The screw nut 32 is rotated to drive the screw guide push rod 12 and the annular piston 13 to perform linear reciprocating motion in the barrel 20.

[0021] The outer surface of the lead screw guide rod 12 is provided with a spiral groove 14 matched with the lead screw nut 32 in the drive motor 30 and a milled flat surface 15 ( Figure 2 a) or keyway 16 ( Figure 2 b); The anti-rotation sleeve 40 is coaxially fixed with the screw nut 32 on the outside of the drive motor housing 33, and is provided with a sliding surface 41 matching the outer contour of the cross section of the screw guide push rod 12. The sliding surface 41 is nested in the outer surface of the screw guide push rod 12 to prevent the screw guide push rod 12 from rotating and provide guidance for the linear sliding of the screw guide push rod 12.

[0022] The anti-rotation sleeve 40 can be fixedly installed on the outside of the driving motor housing 33 by flange, thread or other suitable mechanical connection methods.

[0023] The sliding surface 41 of the anti-rotation sliding sleeve 40 can be made of self-lubricating materials such as polytetrafluoroethylene, oil-containing nylon, polyphenylene sulfide, polyetheretherketone, copper composite graphite, oil-containing powder metallurgy, etc.

[0024] In order to detect the limited position of the linear motion of the spline screw guide rod, a limit detection switch 50 can be provided on the outer side of the drive motor housing 33, and a corresponding limit portion 51 is provided on the screw guide rod.

[0025] The piston type slurry extrusion assembly can use an electric valve to replace the function of the one-way valve, such as Figure 3 The feed check valve 11 and the discharge check valve 22 can be electric valves. When feeding, the feed electric valve is opened and the discharge electric valve is closed. When discharging, the discharge electric valve is opened and the feed electric valve is closed.

[0026] like Figure 4 , Figure 5 As shown, a piston-type slurry continuous extrusion mechanism according to the present invention includes a first piston-type slurry extrusion assembly 200, a second piston-type slurry extrusion assembly 300, a feed pipeline 60, a discharge pipeline 61, a three-way pipeline 62, a storage tank 70 and an electronic control device 80.

[0027] The feed pipeline 60 is connected between the feed check valves of the first piston type slurry extrusion assembly 200 and the second piston type slurry extrusion assembly 300 and the discharge port of the storage tank 70. The discharge check valves of the first piston type slurry extrusion assembly 200 and the second piston type slurry extrusion assembly 300 are connected to the first and second ends of the three-way pipeline 62. The discharge pipeline 61 is connected to the third end of the three-way pipeline 62. The electronic control device 80 is electrically connected to the driving motor 30 and the limit detection switch 50 of the piston type slurry extrusion assembly, and is used to drive the first piston type slurry extrusion assembly 200 and the second piston type slurry extrusion assembly 300 to move alternately so that the slurry is continuously extruded through the discharge pipeline 61 without interruption.

[0028] When the piston-type slurry extrusion assembly adopts an electric valve instead of a one-way valve, the electric control device 80 is also connected to the electric control valve of the piston-type slurry extrusion assembly to control the opening and closing of the electric valve.

[0029] In order to reduce the flow resistance of the slurry in the conveying pipeline and reduce the load of the driving motor, the storage tank 70 adopts a pressurized storage tank and is equipped with an air source 71 to maintain the pressure in the storage tank 70. The pressure range in the storage tank 70 is set to be less than the critical pressure value at which the slurry begins to overflow the discharge pipeline 61 relying solely on air pressure, so as to ensure that the barrel can only extrude and inhale the slurry through the linear movement of the piston.

[0030] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A piston-type slurry extrusion assembly, comprising a feed check valve, a screw guide rod, a ring-shaped piston, a barrel, a discharge check valve, a drive motor and a stop sleeve, characterized in that: The feed one-way valve, the screw guide push rod and the annular piston are connected in series to form a feed channel; the discharge one-way valve is connected to the barrel outlet to form a discharge channel; the barrel is mechanically fixed to the outside of the drive motor housing, and the annular piston is arranged in the barrel; the drive motor shaft is a screw nut; the outer surface of the screw guide push rod is provided with a spiral groove matching the screw nut in the drive motor and at least one milled flat surface or a key groove passing through the two end surfaces along the axial side; the anti-rotation sleeve is coaxial with the screw nut and fixed to the outside of the drive motor housing, and is provided with a sliding surface matching the outer contour of the cross section of the screw guide push rod, and the sliding surface is nested in the outer surface of the screw guide push rod, and is arranged to prevent the screw guide push rod from rotating and provide a guide for the linear sliding of the screw guide push rod; the screw nut of the drive motor is nested in the outer surface of the screw guide push rod, and the screw guide push rod and the annular piston are driven to perform linear reciprocating motion in the barrel through the rotation of the screw nut.

2. A piston-type slurry extrusion device according to claim 1, characterized in that: The driving motor is a stepping motor or a servo motor.

3. A piston-type slurry extrusion assembly according to claim 1, characterized in that: The feed one-way valve and the discharge one-way valve are electric valves. When feeding, the feed electric valve is opened and the discharge electric valve is closed. When discharging, the discharge electric valve is opened and the feed electric valve is closed.

4. The piston-type slurry extrusion assembly according to claim 1, characterized in that: A limit detection switch is provided on the outside of the driving motor housing, and the lead screw guide rod is provided with a matching limit portion for detecting the limited position of the linear motion of the spline lead screw guide rod.

5. A piston-type continuous slurry extrusion mechanism, comprising the first piston-type slurry extrusion assembly and the second piston-type slurry extrusion assembly according to claim 1, a feed pipeline, a discharge pipeline, a three-way pipeline, a storage tank and an electronic control device, characterized in that: The feed pipeline is connected between the feed one-way valves of the first piston type slurry extrusion assembly and the second piston type slurry extrusion assembly and the discharge port of the storage tank; the discharge one-way valves of the first piston type slurry extrusion assembly and the second piston type slurry extrusion assembly are connected to the first and second ends of the three-way pipeline, and the discharge pipeline is connected to the third end of the three-way pipeline; the electronic control device is electrically connected to the driving motor and the limit detection switch of the piston type slurry extrusion assembly, and is used to drive the first piston type slurry extrusion assembly and the second piston type slurry extrusion assembly to move alternately so that the slurry is continuously extruded through the discharge pipeline without interruption.

6. A piston-type slurry continuous extrusion system according to claim 5, characterized in that: The material storage tank is a pressurized material storage tank, and a gas source is configured to maintain the pressure in the material storage tank.

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