Ink supply device, ink supply method and 3D printer

Abstract

The invention belongs to the technical field of 3D printing, and discloses an ink supply device, an ink supply method and a 3D printer. The ink supply device comprises an ink box, an ink inlet pump, an ink suction pump and a spray head, the ink box comprises an ink return supply cavity, an ink inlet cavity and an ink return cavity, the ink return supply cavity is configured to be capable of supplementing ink through the supply device, the ink inlet pump is arranged between the ink return supply cavity and the ink inlet cavity in a communicating mode, and the ink suction pump is arranged between the ink return cavity and the ink return supply cavity in a communicating mode; the spray head is arranged on the ink box and comprises an ink flow channel and a nozzle communicated with the ink flow channel, the ink inlet end of the ink flow channel is communicated with the ink inlet cavity, and the ink return end of the ink flow channel is communicated with the ink return cavity. According to the ink supply device, the ink supply method and the 3D printer provided by the invention, the limit of original gas negative pressure for controlling ink circulation flow can be broken through, so that the circulation requirement of ink with high viscosity and high flow rate requirement is met, the pressure control is convenient, and the pressure fluctuation is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to an ink supply device, an ink supply method and a 3D printer. Background Art

[0002] 3D printer, also known as three-dimensional printer, is a rapid prototyping process equipment. As an efficient and environmentally friendly molding technology, 3D printing technology is widely used in printing sand molds, metals, ceramics, polymer materials and photosensitive resin materials.

[0003] In the prior art, the ink supply device of a 3D printer usually uses a vacuum negative pressure difference to control the circulation of ink. The disadvantages of this method are: first, the vacuum negative pressure value is limited. For some inks with high viscosity, such as precision casting wax with a viscosity coefficient of more than 35, if the gas pressure difference is used as the power source for ink circulation, the flow rate is somewhat insufficient. However, precision casting wax has a significant effect on solving the layer crack problem, and the precision casting wax has very little deformation at room temperature. If the 3D printer can be used to print precision casting wax, it will provide a precision casting solution for some complex parts with high deformation control requirements. Secondly, because gas is easily compressed or expanded by external force, the gas flow in the pipeline is seriously lagging, which is prone to large pressure fluctuations and is difficult to control as a stable pressure source, affecting the printing effect of the final model.

[0004] Therefore, there is an urgent need to provide an ink supply device, an ink supply method and a 3D printing device to solve the above problems. Summary of the invention

[0005] The first purpose of the present invention is to provide an ink supply device that can break through the limit of the original gas negative pressure to control the circulation flow of ink, thereby meeting the circulation requirements of ink with high viscosity and large flow requirements, and facilitating pressure control and reducing pressure fluctuations.

[0006] The second purpose of the present invention is to provide an ink supply method that can break through the limitations of the original gas negative pressure control of ink circulation flow, thereby meeting the circulation requirements of inks with high viscosity and large flow requirements, and facilitating pressure control and reducing pressure fluctuations.

[0007] The third object of the present invention is to provide a 3D printer that can break through the limitation of the original gas negative pressure to control the circulation flow of ink, thereby meeting the circulation requirements of ink with high viscosity and large flow requirements, and facilitating pressure control and reducing pressure fluctuations.

[0008] To achieve this object, the present invention adopts the following technical solutions:

[0009] An ink supply device, comprising

[0010] An ink cartridge, comprising an ink return supply chamber, an ink inlet chamber and an ink return chamber, wherein the ink return supply chamber is configured to be able to be replenished with ink through a replenishing device;

[0011] An ink feed pump and an ink suction pump, wherein the ink feed pump is disposed between the ink return supply chamber and the ink feed chamber, and the ink suction pump is disposed between the ink return chamber and the ink return supply chamber;

[0012] A nozzle is arranged on the ink cartridge, and the nozzle includes an ink flow channel and a nozzle connected to the ink flow channel, the ink inlet end of the ink flow channel is connected to the ink inlet cavity, and the ink return end of the ink flow channel is connected to the ink return cavity.

[0013] As an optional solution, it also includes a first pressure transmitter arranged on the ink inlet chamber and a second pressure transmitter arranged on the ink return chamber, the first pressure transmitter is communicatively connected to the ink inlet pump, and the second pressure transmitter is communicatively connected to the ink suction pump.

[0014] As an optional solution, the rotation speed of the ink suction pump is less than or equal to the rotation speed of the ink supply pump.

[0015] As an optional solution, the ink cartridge also includes a vacuum chamber, in which a degassing membrane assembly is provided, one end of the degassing membrane assembly is connected to the outlet of the ink feed pump, and the other end of the degassing membrane assembly is connected to the inlet of the ink feed chamber; a buffer structure is provided in the degassing membrane assembly.

[0016] As an optional solution, a liquid level sensor is provided in the ink return supply cavity, and the liquid level sensor is communicatively connected with the ink feed pump.

[0017] As an optional solution, a connecting port is provided between the ink inlet chamber and the ink return supply chamber, and a mechanical pressure relief valve is provided in the connecting port. The mechanical pressure relief valve is used for one-way pressure relief from the ink inlet chamber to the ink return supply chamber.

[0018] As an optional solution, the ink cartridge is heatable, and is provided with a first temperature sensor and a second temperature sensor. The first temperature sensor is used to detect the temperature of the ink cartridge, and the detection end of the second temperature sensor extends into the ink inlet cavity and is used to detect the temperature of the ink; the top cover of the ink cartridge is provided with a sealing cover.

[0019] An ink supply method, using the above ink supply device, the ink supply method comprises:

[0020] S1: Replenishing ink into the ink return supply chamber through the replenishing device. When the liquid level in the ink return supply chamber reaches a preset liquid level, turning on the ink feed pump, and the ink feed pump sequentially pumps the ink in the ink return supply chamber into the ink feed chamber, the ink flow channel and the ink return chamber;

[0021] S2: Turn on the ink suction pump to make the ink return from the ink return chamber to the ink return supply chamber, so as to form a low-speed circulation of the ink from the ink return supply chamber, the ink inlet chamber, the ink flow channel, the ink return chamber and then to the ink return supply chamber;

[0022] S3: increasing the rotation speeds of the ink inlet pump and the ink suction pump to eject ink from the nozzle, and starting printing after stabilization.

[0023] As an optional solution, the ink supply device further includes a first pressure transmitter disposed on the ink inlet chamber, and a second pressure transmitter disposed on the ink return chamber, the first pressure transmitter being communicatively connected to the ink inlet pump, and the second pressure transmitter being communicatively connected to the ink suction pump;

[0024] The S2 specifically includes: when the pressure value detected by the second pressure transmitter reaches a first set value, turning on the ink suction pump;

[0025] The S3 specifically includes: increasing the rotation speeds of the ink inlet pump and the ink suction pump until the pressure value detected by the first pressure transmitter reaches a second set value, and the pressure value detected by the second pressure transmitter reaches a third set value, and printing can be started after the pressure values ​​are stable.

[0026] A 3D printer comprises the above-mentioned ink supply device.

[0027] Beneficial effects of the present invention:

[0028] The present invention provides an ink supply device. Compared with a traditional system that uses gas negative pressure to control ink circulation (suitable for ink with a viscosity of 5 to 25), firstly, it can break through the limit of traditional gas negative pressure to control the circulation flow of ink, and does not use positive and negative pressure of gas. Instead, it uses the liquid pressure (higher than gas pressure) directly generated by an ink inlet pump and an ink suction pump to meet the ink recirculation requirements with high viscosity and large flow requirements, thereby realizing the printing of ink with a wider viscosity range (viscosity coefficient of 5 to 100), such as precision casting wax (viscosity coefficient exceeds 35), so that the 3D printer can be used for printing precision casting wax, breaking through the technical bottleneck, and providing a precision casting solution for some complex parts with high deformation control requirements; secondly, it can facilitate the control of pressure, reduce pressure fluctuations, and ensure the printing effect of the final model.

[0029] The present invention also provides an ink supply method. By adopting the above-mentioned ink supply device, it is possible to break through the limit of the original gas negative pressure to control the circulation flow of ink, thereby meeting the circulation requirements of ink with high viscosity and large flow requirements, and facilitating pressure control and reducing pressure fluctuations.

[0030] The present invention also provides a 3D printer, which, by providing the above-mentioned ink supply device, can break through the limitation of the original gas negative pressure to control the circulation flow of ink, thereby meeting the circulation requirements of ink with high viscosity and large flow requirements, and facilitating pressure control and reducing pressure fluctuations. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the ink supply device provided by the present invention;

[0032] Figure 2 is a transverse cross-sectional view of the ink supply device provided by the present invention;

[0033] Figure 3 It is a longitudinal sectional view of the ink supply device provided by the present invention.

[0034] In the figure:

[0035] 10. Supply device;

[0036] 1. Ink cartridge; 11. Ink return supply chamber; 12. Ink inlet chamber; 13. Ink return chamber; 14. Vacuum chamber; 15. First temperature sensor; 16. Second temperature sensor; 17. Sealing cover; 18. Connector; 2. Ink inlet pump; 3. Ink suction pump; 4. Nozzle; 41. Ink flow channel; 411. Ink inlet end; 412. Ink return end; 42. Nozzle; 5. First pressure transmitter; 6. Second pressure transmitter; 7. Degassing membrane assembly; 71. Buffer structure; 8. Liquid level sensor; 9. Mechanical pressure relief valve. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0038] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0040] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0041] like Figures 1 to 3 As shown, this embodiment provides an ink supply device, which is applied to a 3D printer and is used to supply ink to the 3D printer.

[0042] Specifically, the ink supply device includes an ink cartridge 1, an ink feed pump 2, an ink suction pump 3, and a nozzle 4. The ink cartridge 1 includes an ink return supply chamber 11, an ink feed chamber 12, and an ink return chamber 13. The ink return supply chamber 11 is configured to be able to be replenished with ink through a replenishing device 10. The ink feed pump 2 and the ink suction pump 3 are both arranged on the ink cartridge 1. The ink feed pump 2 is connected and arranged between the ink return supply chamber 11 and the ink feed chamber 12. The ink suction pump 3 is connected and arranged between the ink return chamber 13 and the ink return supply chamber 11. The nozzle 4 is arranged on the ink cartridge 1. In this embodiment, the nozzle 4 is arranged at the bottom of the ink cartridge 1. In other embodiments, the nozzle 4 can also be arranged on the peripheral side of the ink cartridge. The nozzle 4 includes an ink flow channel 41 and a nozzle 42 connected to the ink flow channel 41. The ink inlet end 411 of the ink flow channel 41 is connected to the ink inlet cavity 12, and the ink return end 412 of the ink flow channel 41 is connected to the ink return cavity 13 to form an ink circulation flow path of the ink return supply cavity 11, the ink feed pump 2, the ink feed cavity 12, the ink flow channel 41, the ink return cavity 13 and the ink suction pump 3. Among them, the nozzles 42 are arranged uniformly, and uniform ink jetting can be achieved through the multiple nozzles 42 connected to the ink flow channel 41.

[0043] When the ink supply device provided in this embodiment is used, the ink is first replenished into the ink return supply chamber 11 through the replenishing device 10. When the liquid level in the ink return supply chamber 11 reaches the preset liquid level, the ink feed pump 2 is turned on and maintained at a low speed, and the ink feed pump 2 pumps the ink in the ink return supply chamber 11 into the ink feed chamber 12, the ink flow channel 41 and the ink return chamber 13 in sequence. After the ink flows into the ink return chamber 13, the ink suction pump 3 is turned on and maintained at a low speed, so that the ink returns from the ink return chamber 13 to the ink return supply chamber 11, thereby forming a low-speed circulation of the ink from the ink return supply chamber 11, the ink feed chamber 12, the ink flow channel 41, the ink return chamber 13 and then to the ink return supply chamber 11, so that the air in the flow path is discharged, and the precipitation and agglomeration of the ink due to standing still is reduced, and even the nozzle 42 is blocked to cause local non-ink spraying. Afterwards, the rotation speeds of the ink inlet pump 2 and the ink suction pump 3 are increased until the nozzle 42 reaches the pressure and flow requirements for inkjet, so that the ink is ejected from the nozzle 42. Printing can begin after the pressure stabilizes. During printing or a short pause, the ink supply device is in this working state. When printing is stopped, the ink inlet pump 2 and the ink suction pump 3 are reduced to the previous lower rotation speed to maintain the low-speed flow of the ink and avoid ink deposition and agglomeration. The printing stop state can also be entered after a short pause and a long period of inactivity.

[0044] It can be seen that the ink supply device provided in this embodiment, compared with the traditional system that uses gas negative pressure to control ink circulation (suitable for ink with a viscosity of 5 to 25), can, firstly, break through the limit of traditional gas negative pressure to control the circulation flow of ink. Instead of using positive and negative pressure of gas, it uses the liquid pressure (higher than gas pressure) directly generated by the ink inlet pump 2 and the ink suction pump 3 to meet the ink recycling requirements with high viscosity and large flow requirements, thereby realizing the printing of ink with a wider viscosity range (viscosity coefficient of 5 to 100), such as precision casting wax (viscosity coefficient exceeds 35), so that the 3D printer can be used for printing precision casting wax, breaking through the technical bottleneck and providing a precision casting solution for some complex parts with high deformation control requirements; secondly, it can facilitate pressure control, reduce pressure fluctuations, and ensure the printing effect of the final model.

[0045] Furthermore, if Figure 2 and Figure 3As shown, the ink supply device also includes a first pressure transmitter 5 arranged on the ink inlet chamber 12, and a second pressure transmitter 6 arranged on the ink return chamber 13. The first pressure transmitter 5 is connected to the ink inlet pump 2 through a controller, and the second pressure transmitter 6 is connected to the ink suction pump 3 through a controller. The first pressure transmitter 5 is used to detect the ink pressure in the ink inlet chamber 12, and by changing the rotation speed of the ink inlet pump 2, the first pressure transmitter 5 can reach its set positive pressure value. The second pressure transmitter 6 is used to detect the ink pressure in the ink return chamber 13. The controller controls the opening of the ink suction pump 3 according to the detection value obtained by the second pressure transmitter 6, and by changing the rotation speed of the ink suction pump 2, the second pressure transmitter 6 can reach its set positive pressure value. Among them, the controller is a prior art, and the present application can adopt any controller and electrical connection method that can achieve the above functions.

[0046] Specifically, when the ink feed pump 2 is turned on, the ink feed pump 2 first pumps the ink in the ink return supply chamber 11 into the ink feed chamber 12, and the first pressure transmitter 5 in the ink feed chamber 12 begins to have pressure feedback. As the ink is continuously pumped in, the ink enters the ink flow channel 41 and the ink return chamber 13 in turn. The positive pressure value detected by the first pressure transmitter 5 reaches its fourth set value. When the pressure value detected by the second pressure transmitter 6 in the ink return chamber 13 reaches its first set value, the controller controls the ink suction pump 3 to turn on and maintain a low speed, thereby forming a low-speed circulation of ink from the ink return supply chamber 11, the ink feed chamber 12, the ink flow channel 41, the ink return chamber 13 and then to the ink return supply chamber 11, so that the air in the flow path is discharged, and the speed of the ink suction pump 3 is kept lower than the speed of the ink feed pump 2, so that the ink intake amount is greater than the ink return amount, thereby avoiding the suction of gas from the nozzle 42. It should be noted that when the pressure value detected by the second pressure transmitter 6 reaches its first set value, it means that the ink has just entered the ink return chamber 13. When the second pressure transmitter 6 can just detect a positive pressure value, it proves that there is basically no gas in the flow path. At this time, the ink suction pump 3 can be controlled to start.

[0047] Then, after a period of circulation, the speeds of the ink feed pump 2 and the ink suction pump 3 are increased until the pressure value detected by the first pressure transmitter 5 reaches its second set value, and the pressure value detected by the second pressure transmitter 6 reaches its third set value. At this time, the nozzle 42 reaches the pressure and flow requirements of inkjet, and printing can be started after the pressure value is stabilized by PID control. At this time, the speed of the ink suction pump 3 is kept equal to the speed of the ink feed pump 2. It should be noted that the second set value is greater than the fourth set value, and the third set value is greater than the first set value. The first set value, the second set value, the third set value and the third set value are all set according to the viscosity of the ink and the flow resistance of the nozzle 4, and no specific limitation is made here. It can be seen that the entire ink supply process can accurately control the actions of the ink feed pump 2 and the ink suction pump 3 through the feedback of the first pressure transmitter 5 and the second pressure transmitter 6, avoid the presence of gas in the flow path, and ensure the stability of the entire printing process, thereby improving the printing quality and printing stability.

[0048] Furthermore, if Figure 2 As shown, the ink cartridge 1 also includes a vacuum chamber 14, in which a degassing membrane assembly 7 is provided, one end of the degassing membrane assembly 7 is connected to the outlet of the ink feed pump 2, and the other end of the degassing membrane assembly 7 is connected to the inlet of the ink feed chamber 12. After the ink feed pump 2 is turned on, the ink feed pump 2 pumps the ink from the ink return supply chamber 11 into the degassing membrane assembly 7 for degassing before entering the ink feed chamber 12. Figure 1 The ink cartridge 1 is provided with a connector 18 connected to the vacuum chamber 14. The connector 18 is used to connect to the vacuum pump. The vacuum pump is used to pump the vacuum chamber 14 into a negative pressure state. The degassing membrane assembly 7 is a membrane structure with a number of degassing holes. The pore size of the degassing holes is larger than the pore size of the gas molecules and smaller than the pore size of the ink molecules. The vacuum chamber 14 is used to suck the gas out of the degassing membrane assembly 7. When the ink feed pump 2 is turned on, the vacuum pump is also turned on to pump the vacuum chamber 14 into a negative pressure below -500mbar. When the ink passes through the degassing membrane assembly 7, the gas in the degassing membrane assembly 7 is sucked out by the vacuum chamber 14, thereby achieving degassing of the ink, so that the ink entering the ink feed chamber 12 is in an airless state as much as possible, avoiding gas from mixing into the nozzle 4 and affecting the printing quality.

[0049] like Figure 2 As shown, a buffer structure 71 is provided in the degassing membrane assembly 7. The buffer structure 71 is used to buffer the mixed flow, so that the ink is fully in contact with the degassing membrane assembly 7, so that the ink is more fully degassed and the degassing effect is improved.

[0050] like Figure 2As shown, a liquid level sensor 8 is provided in the ink return supply chamber 11, and the liquid level sensor 8 is connected to the ink feed pump 2 through a controller. The controller controls the opening or closing of the ink feed pump 2 according to the detection value of the liquid level sensor 8. Specifically, the liquid level sensor 8 has a high liquid level value and a low liquid level value. The supply device 10 injects ink into the ink return supply chamber 11. When the value detected by the liquid level sensor 8 reaches the high liquid level value, the controller controls the ink feed pump 2 to start and maintain a lower speed to pump the ink from the ink return supply chamber 11 into the ink feed chamber 12. After a period of use, as the ink in the ink return supply chamber 11 decreases, when the value detected by the liquid level sensor 8 reaches the low liquid level value, the controller controls the supply device 10 to start and inject ink into the ink return supply chamber 11.

[0051] like Figure 2 As shown, a connecting port is provided between the ink inlet chamber 12 and the ink return supply chamber 11, and a mechanical pressure relief valve 9 is provided in the connecting port. The mechanical pressure relief valve 9 is used for one-way pressure relief from the ink inlet chamber 12 to the ink return supply chamber 11. For example, when the ink suction pump 3 fails, the ink cannot be returned from the ink return chamber 13 to the ink return supply chamber 11 through the ink suction pump 3, but the ink inlet pump 2 has been pumping ink into the flow path, so the pressure in the flow path will exceed the specified range. At this time, the liquid pressure in the ink inlet chamber 12 will push open the valve core of the mechanical pressure relief valve 9, and achieve one-way pressure relief from the ink inlet chamber 12 to the ink return supply chamber 11, thereby protecting the nozzle 4 and the degassing membrane assembly 7 and avoiding device damage. Among them, the structure of the mechanical pressure relief valve 9 is similar to that of a one-way valve, which belongs to the prior art and will not be repeated here.

[0052] In an optional embodiment, when the viscosity of the selected ink is relatively large, such as precision casting wax, the ink cartridge 1 can be selected as an ink cartridge 1 with a self-heating function. The ink cartridge 1 is provided with a first temperature sensor 15 and a second temperature sensor 16. The first temperature sensor 15 is used to detect the temperature of the ink cartridge 1. The detection end of the second temperature sensor 16 extends into the ink inlet cavity 12 and is used to detect the temperature of the ink. The first temperature sensor 15 and the second temperature sensor 16 are respectively connected to the heating device of the ink cartridge 1 through a controller. The ink cartridge 1 is a metal shell. A heating device such as a heating wire or a heating sheet can be configured inside or outside the interlayer of the ink cartridge 1. By heating the ink cartridge 1, the ink entering the ink inlet cavity 12 can be heated through heat exchange, so that the ink is converted from a solid state to a liquid state, thereby reducing the viscosity of the ink and increasing the fluidity. It is ensured that under the pressure generated by the ink inlet pump 2 and the ink suction pump 3, the circulation of ink with high viscosity and large flow requirements can be achieved, thereby achieving printing of ink with a wider viscosity range.

[0053] Among them, the controller mainly performs PID temperature control according to the value of the first temperature sensor 15 to control the heating rhythm of the ink cartridge 1. Specifically, when the temperature value detected by the first temperature sensor 15 reaches its set low temperature value, the controller controls the ink cartridge 1 to start heating to ensure the heating temperature of the ink; when the temperature value detected by the first temperature sensor 15 reaches its set high temperature value, the controller controls the ink cartridge 1 to stop heating to avoid damage to other components caused by high temperature. Through the above temperature control process, the ink is maintained within a suitable temperature range. During the temperature control process, the second temperature sensor 16 plays an auxiliary role, detecting the temperature of the ink in real time to prevent the temperature of the ink from being too high or too low. When the temperature of the ink is too high or too low, it can be fed back to the controller and the heating start and stop of the ink cartridge 1 can be controlled accordingly.

[0054] The ink cartridge 1 has a temperature switch to prevent the ink cartridge 1 and the ink from overheating in the event of a malfunction. The nozzle 4 and the replenishing device 10 also have independent over-temperature protection devices to avoid component damage.

[0055] Furthermore, if Figure 1 As shown, the top cover of the ink cartridge 1 is provided with a sealing cover 17, and a microcrystalline glass is provided on the sealing cover 17 to facilitate observation of the flow of ink.

[0056] This embodiment also provides an ink supply method, using the above-mentioned ink supply device, the ink supply method includes:

[0057] S1: Replenishing ink into the ink return supply chamber 11 through the replenishing device 10. When the liquid level in the ink return supply chamber 11 reaches a preset liquid level, the ink feed pump 2 is turned on. The ink feed pump 2 pumps the ink in the ink return supply chamber 11 into the ink feed chamber 12, the ink flow channel 41 and the ink return chamber 13 in sequence.

[0058] S2: Turn on the ink suction pump 3 to make the ink return from the ink return chamber 13 to the ink return supply chamber 11, so as to form a low-speed circulation of the ink from the ink return supply chamber 11, the ink inlet chamber 12, the ink flow channel 41, the ink return chamber 13 and then to the ink return supply chamber 11;

[0059] S3: Increase the rotation speed of the ink inlet pump 2 and the ink suction pump 3 to make the ink spray out from the nozzle 42, and start printing after stabilization.

[0060] Specifically, in step S1, the ink is replenished into the ink return supply chamber 11 through the replenishing device 10, and the liquid level in the ink return supply chamber 11 is detected in real time through the liquid level sensor 8. When the value detected by the liquid level sensor 8 reaches the high liquid level value, the controller controls the ink feed pump 2 to start and maintain a low speed, and the ink is pumped into the ink feed chamber 12, the ink flow channel 41 and the ink return chamber 13 in sequence. At the same time, the vacuum pump is turned on, and the degassing of the ink is achieved through the degassing membrane assembly 7 and the vacuum chamber 14. In step S2, after the ink flows into the ink return chamber 13, the ink suction pump 3 is turned on and maintained at a low speed, so that the ink returns from the ink return chamber 13 to the ink return supply chamber 11, thereby forming a low-speed circulation of the ink from the ink return supply chamber 11, the ink feed chamber 12, the ink flow channel 41, the ink return chamber 13 and then to the ink return supply chamber 11, so that the air in the flow path is discharged, and the precipitation and agglomeration of the ink due to standing is reduced, and even the nozzle 42 is blocked to cause local non-ink spraying. In step S3, the rotation speeds of the ink inlet pump 2 and the ink suction pump 3 are increased until the nozzle 42 reaches the pressure and flow requirements for inkjet, so that the ink is ejected from the nozzle 42. Printing can begin after the pressure stabilizes. During printing or a short pause, the ink supply device maintains this working state. When printing stops, the ink inlet pump 2 and the ink suction pump 3 drop to the previous lower rotation speed to maintain the low-speed flow of the ink and avoid ink deposition and agglomeration. The printing stop state can also be entered after a short pause and a long period of inactivity.

[0061] It can be seen that the ink supply method provided in this embodiment, compared with the traditional method of using gas negative pressure to control ink circulation (suitable for ink with a viscosity of 5 to 25), can, firstly, break through the limit of traditional gas negative pressure to control the circulation flow of ink. Instead of using positive and negative pressure of gas, it uses the liquid pressure (higher than gas pressure) directly generated by the ink inlet pump 2 and the ink suction pump 3 to meet the ink recycling requirements with high viscosity and large flow requirements, thereby realizing the printing of ink with a wider viscosity range (viscosity coefficient of 5 to 100), such as precision casting wax (viscosity coefficient exceeds 35), so that the 3D printer can be used for printing precision casting wax, breaking through the technical bottleneck and providing precision casting solutions for some complex parts with high deformation control requirements; secondly, it can facilitate pressure control, reduce pressure fluctuations, and ensure the printing effect of the final model.

[0062] Further, S2 specifically includes: when the pressure value detected by the second pressure transmitter 6 reaches the first set value, starting the ink suction pump 3;

[0063] S3 specifically includes: increasing the rotation speed of the ink inlet pump 2 and the ink suction pump 3 until the pressure value detected by the first pressure transmitter 5 reaches the second set value, and the pressure value detected by the second pressure transmitter 6 reaches the third set value, and printing can be started after the pressure values ​​are stable.

[0064] Specifically, in step S2, after the ink feed pump 2 is turned on, the ink feed pump 2 first pumps the ink in the ink return supply chamber 11 into the ink feed chamber 12, and the first pressure transmitter 5 in the ink feed chamber 12 begins to have pressure feedback. As the ink is continuously pumped in, the ink successively enters the ink flow channel 41 and the ink return chamber 13, and the positive pressure value detected by the first pressure transmitter 5 is greater than its fourth set value. When the pressure value detected by the second pressure transmitter 6 in the ink return chamber 13 reaches its first set value, the controller controls the ink suction pump 3 to turn on and maintain a low speed, thereby forming a low-speed circulation of ink from the ink return supply chamber 11, the ink feed chamber 12, the ink flow channel 41, the ink return chamber 13 and then to the ink return supply chamber 11, so that the air in the flow path is discharged, and the speed of the ink suction pump 3 is kept lower than the speed of the ink feed pump 2, so that the ink intake amount is greater than the ink return amount, thereby avoiding the suction of gas from the nozzle 42.

[0065] Then, after a period of circulation in step S2, in step S3, the speeds of the ink feed pump 2 and the ink suction pump 3 are increased until the pressure value detected by the first pressure transmitter 5 reaches the second set value, and the pressure value detected by the second pressure transmitter 6 reaches the third set value. At this time, the pressure and flow requirements of the nozzle 42 for ink jetting are met, and printing can be started after the pressure value is stabilized by PID control. At this time, the speed of the ink suction pump 3 is kept equal to the speed of the ink feed pump 2. During the entire ink supply process, the actions of the ink feed pump 2 and the ink suction pump 3 are accurately controlled through the feedback of the first pressure transmitter 5 and the second pressure transmitter 6, so as to avoid the presence of gas in the flow path and ensure the stability of the entire printing process, thereby improving the printing quality and printing stability.

[0066] This embodiment also provides a 3D printer, including the above-mentioned ink supply device. Among them, except for the above-mentioned ink supply device, the remaining structures of the 3D printer are all prior art and will not be described in detail here. In addition, the 3D printer includes the same structure and beneficial effects as the ink supply device in the above-mentioned embodiment. The structure and beneficial effects of the ink supply device have been described in detail in the above-mentioned embodiment and will not be described in detail here.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. An ink supply device, characterized in that: include: An ink cartridge (1) comprises an ink return supply chamber (11), an ink inlet chamber (12) and an ink return chamber (13), wherein the ink return supply chamber (11) is configured to be able to be replenished with ink through a replenishing device (10); An ink feed pump (2) and an ink suction pump (3), wherein the ink feed pump (2) is disposed in communication between the ink return supply chamber (11) and the ink feed chamber (12), and the ink suction pump (3) is disposed in communication between the ink return chamber (13) and the ink return supply chamber (11); A nozzle (4) is arranged on the ink cartridge (1), and the nozzle (4) comprises an ink flow channel (41) and a nozzle (42) connected to the ink flow channel (41), the ink inlet end (411) of the ink flow channel (41) is connected to the ink inlet cavity (12), and the ink return end (412) of the ink flow channel (41) is connected to the ink return cavity (13).

2. The ink supply device according to claim 1, characterized in that: It also includes a first pressure transmitter (5) arranged on the ink inlet chamber (12), and a second pressure transmitter (6) arranged on the ink return chamber (13), wherein the first pressure transmitter (5) is communicatively connected to the ink inlet pump (2), and the second pressure transmitter (6) is communicatively connected to the ink suction pump (3).

3. The ink supply device according to claim 1, characterized in that: The rotation speed of the ink suction pump (3) is less than or equal to the rotation speed of the ink supply pump (2).

4. The ink supply device according to claim 1, characterized in that: The ink cartridge (1) further comprises a vacuum chamber (14), wherein a degassing membrane assembly (7) is provided in the vacuum chamber (14), wherein one end of the degassing membrane assembly (7) is connected to the outlet of the ink feed pump (2), and the other end of the degassing membrane assembly (7) is connected to the inlet of the ink feed chamber (12); and a buffer structure (71) is provided in the degassing membrane assembly (7).

5. The ink supply device according to claim 1, characterized in that: A liquid level sensor (8) is provided in the ink return supply chamber (11), and the liquid level sensor (8) is communicatively connected with the ink feed pump (2).

6. The ink supply device according to claim 1, characterized in that: A communication port is provided between the ink inlet chamber (12) and the ink return supply chamber (11), and a mechanical pressure relief valve (9) is provided in the communication port. The mechanical pressure relief valve (9) is used for one-way pressure relief from the ink inlet chamber (12) to the ink return supply chamber (11).

7. The ink supply device according to claim 1, characterized in that: The ink cartridge (1) is heatable, and is provided with a first temperature sensor (15) and a second temperature sensor (16), wherein the first temperature sensor (15) is used to detect the temperature of the ink cartridge (1), and the detection end of the second temperature sensor (16) extends into the ink inlet cavity (12) and is used to detect the temperature of the ink; the top cover of the ink cartridge (1) is provided with a sealing cover (17).

8. An ink supply method, characterized in that: Using the ink supply device according to any one of claims 1 to 7, the ink supply method comprises: S1: Replenishing ink into the ink return supply chamber (11) through the replenishing device (10); when the liquid level in the ink return supply chamber (11) reaches a preset liquid level, starting the ink supply pump (2); and the ink supply pump (2) sequentially pumps the ink in the ink return supply chamber (11) into the ink supply chamber (12), the ink flow channel (41) and the ink return chamber (13); S2: turning on the ink suction pump (3) to allow the ink to return from the ink return chamber (13) to the ink return supply chamber (11), thereby forming a low-speed circulation of the ink from the ink return supply chamber (11), the ink inlet chamber (12), the ink flow channel (41), the ink return chamber (13) and then to the ink return supply chamber (11); S3: increasing the rotation speed of the ink inlet pump (2) and the ink suction pump (3) so that the ink is ejected from the nozzle (42), and starting printing after stabilization.

9. The ink supply method according to claim 8, characterized in that: The ink supply device further comprises a first pressure transmitter (5) arranged on the ink inlet chamber (12), and a second pressure transmitter (6) arranged on the ink return chamber (13), wherein the first pressure transmitter (5) is communicatively connected to the ink inlet pump (2), and the second pressure transmitter (6) is communicatively connected to the ink suction pump (3); The step S2 specifically includes: when the pressure value detected by the second pressure transmitter (6) reaches a first set value, starting the ink suction pump (3); The S3 specifically includes: increasing the rotation speeds of the ink supply pump (2) and the ink suction pump (3) until the pressure value detected by the first pressure transmitter (5) reaches a second set value, and the pressure value detected by the second pressure transmitter (6) reaches a third set value, and printing can be started after the pressure values ​​are stabilized.

10. A 3D printer, characterized in that: Comprising the ink supply device as described in any one of claims 1-7.

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