CN106623940B - A kind of liquid metal ink jet valve - Google Patents

Abstract

The invention relates to the field of ink-jet printing devices, and discloses a liquid metal ink-jet valve, comprising: a heating chamber with a heating chamber; an inlet for metal powder and liquid metal is provided at the upper end thereof; an electromagnetic drive device and a heating device are provided in it , the heating device melts the metal powder or preheats the liquid metal ink, and the electromagnetic drive device drives the liquid metal ink to move; the liquid metal cavity is provided with a liquid metal chamber and a nozzle; and an insulated push rod and a feedback control device, insulated One end of the push rod extends into the liquid metal chamber, the other end is connected to the reciprocating stepping device, and the feedback control device controls the movement of the reciprocating stepping device according to the position of the liquid metal; wherein the liquid metal chamber communicates with the heating chamber. The invention melts the liquid metal powder and is driven by an electromagnetic drive device and pushed out by an insulating push rod, which overcomes the defects of the liquid metal in the inkjet printing process and realizes continuous, fast and stable inkjet of the liquid metal.

Description

A liquid metal inkjet valve

technical field

The invention relates to the field of inkjet printing devices, in particular to a liquid metal inkjet valve

Background technique

Printed electronics has become an important part of electronic manufacturing technology, and liquid metal occupies an important position in printed electronics because of its high conductivity, simple preparation, and no need for post-processing.

The existing methods of printing liquid metal mainly include contact printing method and atomization spraying method; the ink output speed of the contact printing method is relatively slow, which is only suitable for printing small batches and fine circuits; the atomization spraying method requires pre-fabricated masks. Membrane is more inconvenient. The non-contact inkjet method can effectively increase the ink output speed, make electronic circuits more quickly, and do not need to use a template. However, the properties of liquid metal and traditional ink are very different. Ordinary inkjet valves or inkjet print heads It is difficult to meet the needs of liquid metal inkjet. Liquid metal has low viscosity, high surface tension, high density, excellent electrical conductivity, and poor wettability with various materials. Some metal alloys with melting points higher than room temperature need to be heated, and oxide impurities are prone to affect inkjet quality. Therefore, to use the inkjet method to print liquid metal, it is necessary to design a new structure of inkjet valve or inkjet device for these problems.

Contents of the invention

(1) Technical problems to be solved

The purpose of the present invention is to provide a liquid metal inkjet valve, which overcomes the defects of liquid metal in the inkjet printing process due to its low viscosity, high surface tension, high density, and excellent electrical conductivity, and realizes liquid metal Metal continuous, fast and stable inkjet.

(2) Technical solution

In order to solve the above technical problems, the present invention provides a liquid metal inkjet valve, comprising:

A heating chamber, the heating chamber has a heating chamber; the upper end of the heating chamber is provided with a metal powder inlet; the heating chamber is provided with an electromagnetic drive device and a heating device, and the heating device is used to heat the metal The powder is melted into liquid metal ink, and the electromagnetic drive device is used to drive the liquid metal ink to move;

a liquid metal cavity, the liquid metal cavity is provided with a liquid metal chamber and a nozzle arranged in the liquid metal chamber; and

Insulated push rod and feedback control device, one end of the insulated push rod extends into the liquid metal chamber, and the other end is connected with the reciprocating stepping device, the feedback control device detects the liquid metal in the liquid metal chamber position, and control the movement of the reciprocating stepping device according to its position;

Wherein, the liquid metal chamber communicates with the heating chamber.

Wherein, the heating device is composed of a plurality of metal cylinders and insulating mesh plates.

Wherein, the heat preservation device on the outside of the heating cavity.

Wherein, a filtering device at the lower end of the heating chamber is also included.

Wherein, the heating chamber further includes a liquid level monitoring and pressure control device for monitoring the liquid metal ink level in the heating chamber and controlling the internal pressure of the heating chamber.

Wherein, the connection channel between the heating chamber and the liquid metal chamber is further provided with a bubble removal chamber with a negative pressure device, and the bubble removal chamber and the liquid metal chamber are integrally or separately arranged.

Wherein, the liquid metal cavity is coated with a plating layer.

Wherein, the liquid metal cavity is also provided with a liquid metal recovery and cleaning room, the liquid metal recovery and cleaning room is provided with a driving device and a control valve block, and the liquid metal recovery and cleaning room is respectively connected with the air bubble removal The chamber is connected to the liquid metal chamber, the control valve block is arranged in the liquid metal chamber, and the driving device is used to drive the liquid metal ink in the liquid metal recovery and cleaning chamber.

Wherein, the reciprocating stepping device is a cam linkage mechanism, a pneumatic piston linkage mechanism or an electromagnet pushing mechanism.

Wherein, the feedback control device is a resistance detection device or a current detection device, and the feedback control device surrounds the insulating propulsion rod, and a group of sensors is arranged at the insulating propulsion rod, and a group of sensors can be added at the nozzle or other positions.

(3) Beneficial effects

A liquid metal inkjet valve provided by the present invention uses a heating device to heat and melt the liquid metal, an electric measuring drive device drives the liquid metal, and an insulating push rod gives the liquid metal kinetic energy and pushes it out, which overcomes the existence of the liquid metal in the inkjet printing process. defects, realize liquid metal continuous, fast and stable inkjet.

Description of drawings

Fig. 1 is the schematic diagram of embodiment 1 of a kind of liquid metal inkjet valve of the present invention;

Fig. 2 is a schematic diagram of Embodiment 2 of a liquid metal inkjet valve of the present invention;

Fig. 3 is a schematic diagram of Embodiment 3 of a liquid metal inkjet valve according to the present invention.

In the figure, 1. Heating cavity; 2. Insulated push rod; 3. Reciprocating stepping device; 4. Nozzle; 5. Feedback control device; 6. Liquid metal recovery and cleaning room; 7. Control valve block; 8. Liquid state Metal chamber; 9. Heating chamber; 10. Electromagnetic drive device; 11. Heating device; 12. Filtration device; 13. Heat preservation device; 14. Liquid level detection and pressure control device; 15. Bubble removal chamber; 16. Permanent magnet; 17, electromagnet; 18, air inlet; 19, piston; 20, return spring; 21, cam link mechanism.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

In the description of the present invention, it should be noted that unless otherwise specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection. Connected, or integrally connected; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

Example 1:

As shown in Figure 1, the present invention discloses a liquid metal inkjet valve, comprising: a heating chamber 1 having a heating chamber 9; the upper end of the heating chamber 9 is provided with a metal powder inlet; The heating chamber 9 is provided with an electromagnetic driving device 10 and a heating device 11, the heating device 11 is used to heat the metal powder to melt it into liquid metal ink, and the electromagnetic driving device 10 is used to drive the liquid metal ink movement;

A liquid metal chamber, the liquid metal chamber is provided with a liquid metal chamber 8 and a nozzle 4 located in the liquid metal chamber 8; and

Insulated push rod 2 and feedback control device 5, one end of the insulated push rod 2 extends into the liquid metal chamber 8, the other end is connected with the reciprocating stepping device 3, the feedback control device 5 detects the liquid metal in the Describe the position in the liquid metal chamber 9, and control the motion of the reciprocating stepping device 2 according to its position;

Wherein, the liquid metal chamber 8 communicates with the heating chamber 9 .

Specifically, the liquid metal cavity and the heating cavity may be of an integral structure, or may be of a separate structure, and are sealed and connected by pipes. The liquid metal used in the present invention can be a low-melting-point metal element or metal alloy with a melting point below 400°C, or a mixture of the metal element or metal alloy and nano or micro particles with conductive function. According to the characteristics of liquid metal with low viscosity, high surface tension, high density and excellent electrical conductivity, the liquid metal powder enters from the metal powder inlet at the upper end of the heating chamber 9, is heated by the heating device 11 and melted into liquid metal ink, and is heated by the electromagnetic The driving device 10 makes the liquid metal ink move directionally from the heating chamber 9 to the liquid metal chamber, and the reciprocating stepping device 3 drives the insulating push rod 2 to reciprocate, giving kinetic energy to the liquid metal ink in the liquid metal chamber 8, and pushing out the nozzle 4 . The reciprocating stepping device 3 of this embodiment adopts a cam link mechanism 21 and is driven by a stepping motor to ensure a constant rotation angle of the cam and thus a constant stroke of the push rod. Because the liquid metal ink has a great surface tension, it is difficult to flow in the pipeline only by gravity, but the liquid metal ink also has good conductivity, and the conductive fluid will be forced to move in the magnetic field, so it is applied by the electromagnetic drive device 10. Appropriate electromagnetic fields can effectively push the liquid metal ink to the nozzle. The function of the feedback control device 5 is to detect the position of the liquid metal in the liquid metal chamber 9 , and control the movement of the reciprocating stepping device 2 based on the position of the metal, and then control the movement of the insulating control rod 2 . In order to avoid affecting the feedback detection, the material of the push rod and the nozzle should be insulated, and ceramic materials can generally be used.

A liquid metal inkjet valve provided by the present invention uses a heating device to heat and melt the liquid metal according to the liquid metal's characteristics of low melting point, high surface tension and excellent electrical conductivity. The kinetic energy of the metal is pushed out, which overcomes the defects of liquid metal in the inkjet printing process and realizes continuous, fast and stable inkjet of liquid metal.

Wherein, the heating device 11 is composed of a plurality of metal cylinders and insulating mesh plates. Such a self-feedback heating device, when there is air in the gap between the insulating screens, the entire heating device 11 is non-conductive; when the metal powder fills the gap between the insulating screens, the heating device 11 conducts electricity, generating current between the metal powders and making the metal powders The liquid metal ink is obtained by self-heating and melting, and this method improves the heating efficiency and reduces the total power consumption of the device compared with the heating of the electric heater. Specifically, the heating device 11 is above the electromagnetic driving device 10 , and the melted liquid metal ink moves directionally through the electromagnetic driving device 10 .

Wherein, the heat preservation device 13 on the outside of the heating chamber 1 ensures that the heated metal remains in a liquid state during the ink jetting process.

Wherein, also comprise the filtering device 12 at the lower end of described heating chamber 9, filtering device 12 is the screen board that has good wettability with liquid metal ink and has porous structure, for example porous ceramics, porous nano material, cellulose acetate membrane or poly Fabric media should not be used for amide membranes, etc.; the liquid metal ink obtained by melting metal powder may contain corresponding metal oxides or other impurities, which can be removed by the filter device; the filter device 12 can be taken out for replacement.

Wherein, the heating chamber 9 also includes a liquid level monitoring and pressure control device 14 for monitoring the liquid metal ink level in the heating chamber 9 and controlling the internal pressure of the heating chamber 9 . Specifically, because in the airtight heating chamber 9, the metal powder melts from a solid state to a liquid state, which will cause pressure changes in the heating chamber 9, so it is necessary to adjust the internal pressure value by monitoring the liquid level to prevent the pressure value from being too high. Large, the liquid metal ink is squeezed out of the nozzle 4, so that the liquid metal ink can be driven by the electromagnetic drive device 10 and stably added to the nozzle 4 without directly flowing out. The liquid level monitoring and pressure control device 14 is arranged on the top of the heating chamber 9 to facilitate releasing the pressure in the heating chamber 9 .

Wherein, the connection channel between the heating chamber 9 and the liquid metal chamber 8 is also provided with a bubble removal chamber 15 with a negative pressure device, and the bubble removal chamber 15 is integrated or separated from the liquid metal chamber 8. body settings. Specifically, there is a certain negative pressure in the bubble removal chamber 15, which can break the bubbles therein when the liquid metal ink passes through, so as to eliminate the bubbles so as not to affect the inkjet effect.

Wherein, the liquid metal chamber 8 is coated with a coating, and the coating can improve the wettability between the liquid metal ink and the liquid metal chamber 8, so that the liquid metal ink can flow more easily, such as nano-metal materials, etc., can also use micro Structures such as channels improve the fluidity of the liquid metal. Generally, the liquid metal ink is gallium or gallium-based alloy. At this time, gallium oxide can be used for the coating to reduce the corrosion and wear of other parts by the metal ink and improve the life of the equipment.

Wherein, the liquid metal cavity is also provided with a liquid metal recovery and cleaning room 6, and a drive device and a control valve block 7 are arranged in the liquid metal recovery and cleaning room 6, and the liquid metal recovery and cleaning room 6 are respectively It is connected with the bubble removal chamber 15 and the liquid metal chamber 8, the control valve block 7 is arranged in the liquid metal chamber 8, and the driving device is used to drive the liquid metal recovery and cleaning chamber 6 liquid metal ink. As shown in Figure 1, when the inkjet valve is working normally, the control valve block 7 on the right is closed, and the control valve block 7 on the left is opened, so that the liquid metal chamber 8 is only connected with the bubble removal chamber 15; when the nozzle 4 needs to be cleaned At this time, the control valve block 7 on the right is opened, and the control valve block 7 on the left is closed, and the liquid metal ink between the nozzle 4 and the two control valve blocks 7 is sent to the air bubble removal chamber 15 by the driving device, and can continue to be used. When the inkjet valve is not used for a long time, the nozzle 4 can be cleaned by airflow to remove residual metal ink. The driving device can be a small liquid pump, an electromagnetic driving device or other driving devices. It is also possible to use a three-way valve structure instead of the above two control valves 7 .

Wherein, the feedback control device 5 is a resistance detection device or a current detection device, the feedback control device surrounds the insulating push rod, a group of sensors is arranged at the insulating push rod, and a group of sensors can be added at the nozzle or other positions, The feedback control device 5 also has a sealing function. The advantage of using the cam link mechanism 21 is that the feedback control device 5 can stop the cam at the current position immediately when the feedback control device 5 detects that the ink output condition is abnormal, and the reliability is higher.

The workflow of a kind of liquid metal inkjet valve of the present invention is as follows:

Add the metal powder into the heating device 11, the heating device 11 detects the metal powder and starts to heat and melt the metal powder into liquid metal ink, the electromagnetic drive device 10 drives the liquid metal ink to move directional through the external electromagnetic field, and passes through the air bubble removal chamber In chamber 8, due to the effect of negative pressure, the air bubbles in the liquid metal ink are removed. When inkjet is required, open the left control valve block 7 and close the right control valve block 7; the feedback control device 5 detects the position of the liquid metal and controls the stepper motor to drive the cam linkage 21 to lower the insulating push rod 2, giving The kinetic energy of the liquid metal ink in the liquid metal chamber 8 causes it to be pushed out of the nozzle 4; when the ink ejection is finished, close the left control valve block 7, open the right control valve block 7, and use the driving device to move the two valve blocks together. The liquid metal ink in the space and the nozzle 4 is sucked into the bubble removal chamber 15, and the ink is recovered to ensure the next use.

Example 2:

This embodiment is basically the same as Embodiment 1. For the sake of brevity, in the description process of this embodiment, the same technical features as Embodiment 1 will not be described, and only the differences between this embodiment and Embodiment 1 will be described:

As shown in Figure 2, the reciprocating stepping device 3 of the present embodiment is adsorbed or repelled by an electromagnet 17, and a permanent magnet 16 is arranged on the upper end of the insulating push rod 2, and an electromagnet 17 is arranged above the permanent magnet 16. The current direction of the wire on the iron core controls the magnetic field direction of the electromagnet 17, and then controls the attraction and repulsion between the permanent magnet 16 and the electromagnet 17, and controls the rise and fall of the insulating push rod 2.

Example 3:

This embodiment is basically the same as Embodiment 1. For the sake of brevity, in the description process of this embodiment, the same technical features as Embodiment 1 will not be described, and only the differences between this embodiment and Embodiment 1 will be described:

As shown in Figure 3, the reciprocating stepping device 3 of this embodiment is a pneumatic piston linkage mechanism, a piston is arranged at the upper end of the insulating push rod 2, the insulating push rod 2 is wound with a return spring 20, and the piston 19 is encapsulated in a housing , the casing is provided with an air inlet 18, when ink jetting is required, air can be pumped into the air inlet 18 to lower the piston, thereby controlling the decline of the insulating push rod 2; when the ink jetting ends, the air inlet 18 communicates with the atmosphere, and the insulating push rod 2 rises due to the effect of the back-moving spring 20.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (8)

1. A liquid metal inkjet valve, characterized in that, comprising: A heating chamber (1), the heating chamber (1) has a heating chamber (9); the upper end of the heating chamber (9) is provided with a metal powder inlet; the heating chamber (9) is provided with Electromagnetic driving device (10) and heating device (11), described heating device (11) is used for heating metal powder, makes it melt into liquid metal ink, and described electromagnetic driving device (10) is used for driving described liquid metal ink sports; A liquid metal cavity, the liquid metal cavity is provided with a liquid metal chamber (8) and a nozzle (4) located in the liquid metal chamber (8); and an insulated push rod (2) and a feedback control device (5), one end of the insulated push rod (2) extends into the liquid metal chamber (8), and the other end is connected with the reciprocating stepping device (3), the The feedback control device (5) detects the position of the liquid metal in the liquid metal chamber (9), and controls the movement of the reciprocating stepping device (3) according to its position; Wherein, the liquid metal chamber (8) communicates with the heating chamber (9); A bubble removal chamber (15) with a negative pressure device is also provided on the connecting channel between the heating chamber (9) and the liquid metal chamber (8), and the bubble removal chamber (15) is connected to the liquid metal chamber The chamber (8) is set as one or separately; The liquid metal cavity is also provided with a liquid metal recovery and cleaning room (6), the liquid metal recovery and cleaning room (6) is provided with a driving device and a control valve block (7), and the liquid metal recovery and cleaning The chamber (6) is respectively connected with the bubble removal chamber (15) and the liquid metal chamber (8), the control valve block (7) is arranged in the liquid metal chamber (8), and the driving The device is used to drive the liquid metal ink in the liquid metal recovery and cleaning chamber (6). 2. The liquid metal inkjet valve according to claim 1, characterized in that, the heating device (11) is composed of several metal cylinders and an insulating mesh plate. 3. The liquid metal inkjet valve according to claim 1, characterized in that a heat preservation device (13) is provided outside the heating cavity (1). 4. The liquid metal inkjet valve according to claim 1, further comprising a filter device (12) at the lower end of the heating chamber (9). 5. The liquid metal inkjet valve according to claim 1, characterized in that, in the heating chamber (9), a liquid level monitoring and pressure control device (14) is also included for monitoring the heating chamber (9) liquid metal ink level height and control the internal pressure of the heating chamber (9). 6. The liquid metal inkjet valve according to claim 1, characterized in that, the inside of the liquid metal chamber (8) is coated with a coating. 7. The liquid metal inkjet valve according to claim 1, characterized in that, the reciprocating stepping device (3) is a cam linkage (21), a pneumatic piston linkage or an electromagnet pushing mechanism. 8. The liquid metal inkjet valve according to claim 1, characterized in that, the feedback control device (5) is a resistance detection device or a current detection device, and the feedback control device (5) surrounds the insulating push rod (2), a group of sensors is arranged at the insulating propulsion rod (2), and a group of sensors is added at the nozzle (4).