A temperature control method for industrial additive manufacturing

Abstract

The present invention provides an industrial additive manufacturing temperature control method, comprising a box body, wherein a first cavity is provided in the box body, the upper end of the box body is connected to one end of a main air pipe, the main air pipe is connected to the first cavity, the other end of the main air pipe is connected to a bottom diffusion plate, the bottom diffusion plate is connected to the first cavity, a heating pipe and a cooling pipe are connected along the main air pipe, the heating pipe is provided with a heating device, the heating device comprises a first heating pipe and a heating mechanism, the first heating pipe is outer-circuited with a heating mechanism; the cold air pipe is provided with a cooling device, and the feedforward heating demand and the printing steady-state control stage are performed through the heating process, and the feedforward heating demand and feedback adjustment are achieved to achieve precise temperature control and good product molding effect.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a temperature control method for industrial additive manufacturing. Background Art

[0002] Current industrial additive manufacturing applications involve either an open environment, where the printing platform is relatively open to the surroundings and lacks an external cover; or a closed environment, where a box covers the outside of the printing platform to achieve a constant temperature. However, regardless of the above environments, the printing environment suffers from poor temperature control. Consequently, in some industrial applications requiring high temperatures, such as continuous printing operations between 250°C and 500°C, the printed portion may have cooled while the unprinted portion remains at a high temperature, leading to uneven condensation.

[0003] Especially in the additive manufacturing process of engineering materials for non-metallic materials, such as when printing PEEK materials, there are strict requirements for the 3D printing environment. Due to the sensitivity of PEEK materials to temperature, ensuring temperature stability during the printing process is crucial. Therefore, a constant temperature box is needed to provide a stable environment for 3D printing equipment to reduce large temperature fluctuations, thereby ensuring printing quality to meet the needs of industrial fields with strict requirements such as aerospace, medical, automotive and electronics. Therefore, a temperature control box needs to be set on the printing platform.

[0004] For example, the patent document with patent application number 202410498362.1 and publication date 2024.07.23 discloses a 3D printing temperature control device and method for reducing deformation of molded parts. It includes a printing point temperature control unit, an ambient temperature control unit, a printing part heat dissipation unit, and a formed entity surface temperature acquisition unit; the printing point temperature control unit is used to regulate the temperature of the formed entity surface at the printing point; the ambient temperature control unit is used to regulate the ambient temperature outside the formed entity, and the formed entity is placed above the hot bed; the printing part heat dissipation unit is used to uniformly and synchronously dissipate heat to each area of ​​the printed entity; the formed entity surface temperature acquisition unit is used to collect and output the surface temperature of the formed entity. The device and method can compensate for the temperature in real time and accurately during the 3D printing process, reducing warping deformation caused by uneven temperature between layers, sudden cooling of molten filament, and inconsistent cooling rates in different areas of the molded part, thereby improving the accuracy of fused deposition modeling 3D printing technology.

[0005] According to the above literature, before printing begins, the telescopic rod adjusts the quartz heating tube to its initial position to ensure that the heating area covers the printing area. During the printing process, the telescopic rod can adjust the position of the quartz heating tube in real time as needed to adapt to the shape and size of the printed part. If there is a problem with the synchronous control, the relative position of the heating area and the printing area may change, affecting the printing effect. In addition, the heat is only dissipated through the ventilation duct and the cooling fan to lower the temperature, and the heating temperature is controlled by the heating tube. For the heating process, if the heating tube is directly activated for temperature control when the temperature is not high enough, it is easy to go directly from a relatively low temperature to a high temperature, resulting in large temperature fluctuations and ultimately affecting the printing effect. In addition, due to the layout of the ventilation duct and the unevenness of the air flow, the printed part may suffer from uneven heat dissipation, thus affecting the molding quality. Summary of the Invention

[0006] The present invention provides an industrial additive manufacturing temperature control method, which can accurately control the temperature and achieve good molding effect.

[0007] To achieve the above-mentioned purpose, the technical solution of the present invention is: a temperature control method for industrial additive manufacturing, which is implemented by a temperature control device. The temperature control device includes a box body, a first cavity is provided in the box body, the upper end of the box body is connected to one end of the main air pipe, the main air pipe is connected to the first cavity, the other end of the main air pipe is connected to the bottom diffuser, the bottom diffuser is connected to the first cavity, a heating pipe and a cooling pipe are provided along the main air pipe, the heating pipe is provided with a heating device and a heating valve, the cold air pipe is provided with a cooling device and a cooling valve, and a 3D printing nozzle is provided in the box body.

[0008] The specific steps include: S1 heating stage, based on the preset target temperature and actual temperature difference, the box heat storage capacity coefficient and the set time, the feedforward heating demand will be calculated ; Then calculate the heating valve opening according to the feedforward heating demand and the maximum heating capacity ; Adjust the heating valve opening from the preset opening size to the heating valve opening according to the preset rate ; Determine the cooling valve opening degree according to the heat generated by the print head, the maximum heat dissipation power of the cooling device, and the minimum value of the set opening degree; adjust the cooling valve opening degree from the closed state to the cooling valve opening degree according to the preset valve opening rate;

[0009] During the steady-state control phase of S2 printing, the heating valve opening is determined based on the heat generated by the print head, the current opening of the cooling valve, the maximum heat generated by cooling, and the maximum heat generated by heating. ; Then through PID feedback regulation, the cooling valve opening is adjusted according to the increased heat generated by printing;

[0010] S3: Maintenance control phase after printing is completed, calculate the heat dissipation power ; And determine the opening of the heating valve according to the heat dissipation power and the maximum heat generated by the heating valve and keep the cooling valve in the closed state;

[0011] S4 is the non-printing state maintenance stage, and the heating valve is closed at a preset rate.

[0012] The above setting is that a first cavity is provided in the box body, and the first cavity can be used to place the 3D printing nozzle. A heating pipe is connected to one side of the main air pipe. When the temperature in the first cavity is lower than the set temperature, the heating valve in the heating pipe controls the gas in the main air pipe to enter the first heating pipe. The heating device heats the gas in the first heating pipe to complete the heating of the gas. The heated gas continues to flow downward into the main air pipe, and then enters the bottom diffusion disk from the main air pipe; the cooling pipe is provided with a first cooling pipe, and several second cooling pipes are provided in the first cooling pipe. When the temperature in the first cavity is higher than the set temperature, cooling is achieved by opening the cooling valve; the heated or cooled gas flows through the main air pipe to the bottom diffusion disk, and the gas flows from the bottom diffusion disk to the first cavity to complete the temperature regulation of the box.

[0013] During the temperature control process, in the heating stage, the feedforward heating demand is first determined by the difference between the target temperature and the actual temperature, and the opening of the heating valve is determined according to the feedforward heating demand, and the opening of the cooling valve is determined according to the heat generated by the print head and the maximum cooling temperature. The heating valve is then adjusted from the initial opening to the opening of the heating valve at a preset rate, and the cooling valve is adjusted from the closed state to the opening of the cooling valve at a preset speed. This ensures that the heating valve and the cooling valve are adjusted at a certain rate, and the feedforward heating demand can be met after the heating valve is opened, so that the printing area does not experience a linear temperature rise, and the temperature change process in the heating stage is well controlled. When printing is in steady state, the feedforward heating valve opening is determined by the heat generated by the heating valve and the cooling temperature and maximum heating temperature generated by the cooling valve at the current opening, and the opening of the heating valve is preliminarily determined. Then, the dynamic openings of the heating valve and the cooling valve are adjusted by the PID algorithm, so that the preset temperature can be maintained reliably and stably in steady state. In addition, after printing is completed, the cooling valve is closed and the opening of the heating valve is determined by the heat dissipation power to maintain a certain temperature of the box, so as to prevent direct cooling from causing the molded parts to go from a hot state to a cold state, thereby causing depressions in some parts and affecting the molding effect. In addition, when the non-printing state is maintained, the heating valve is directly closed to reduce energy consumption while ensuring the cooling effect of the molded product. By controlling different temperatures at different stages, good temperature control and molding effects are ensured.

[0014] Further, in step S1: feedforward heating demand , C is the preset box's heat storage capacity, Tset is the target temperature, T0 is the normal temperature, △t is the set time; the heating valve opening ; The maximum heating power provided by the heating device, the cooling valve opening ;P cool_max is the maximum heat dissipation power of the cooling device, P print The heat generated by printing.

[0015] The above settings determine the feedforward heating demand during the heating stage by setting the difference between the target temperature and the actual temperature, the heat storage capacity of the box, and the set time ratio, so as to ensure that the feedforward heating demand can meet the requirements of the target temperature value, and determine the opening of the heating valve by ratioing the feedforward heating demand with the maximum heating heat of the heating valve, so that the heating valve can reach the preset heating temperature under the heating valve opening. In order to prevent the cooling valve from being directly changed from closed to open when cooling is required, thereby causing a large temperature fluctuation range, the opening of the cooling valve is set to the minimum value between the ratio of the heat generated by the print head to the maximum heat of the cooling valve and the preset 5%, so that the opening of the cooling valve will not be too large or too small.

[0016] Furthermore, in step S2, the heating valve opening ;

[0017] And step S2 also includes adjusting the opening of the cooling valve when the film thickness exceeds the preset value. ; The heat required to generate by the print head to increase the film thickness.

[0018] With the above configuration, the heating valve is determined by the ratio of the heat generated by the heating valve to the opening of the cooling valve, and the difference in heat generated by the cooling valve to the maximum heat generated by the heating valve. This allows the heating valve opening to be determined based on the temperature difference between the heating and cooling valves, enabling more precise control of the heating temperature. Furthermore, when the film thickness increases to a preset value, the cooling valve opening is adjusted. This allows the cooling valve opening to dynamically adjust its initial opening based on the increase in film thickness, enabling more reliable control.

[0019] Furthermore, in step S3 , is the actual temperature, is the ambient temperature, k loss is the heat dissipation coefficient, and then calculate the heating valve opening At this time, close the cooling valve and rely on the heating valve to maintain the temperature.

[0020] The above settings determine the opening of the heating valve by the heat dissipation power, ensuring that the opening of the heating valve can be adjusted in real time according to the heat dissipation situation in steady state.

[0021] Furthermore, step S4 also includes: when the temperature rises to the preset first high temperature value, the cooling valve is opened. When the temperature is lower than the second height value, the heating valve opens at a rate of 5%. The rate is adjusted.

[0022] With the above settings, when the temperature is too high, the cooling valve will be adjusted. When the temperature is lower than the second high temperature value, the heating valve will be adjusted at the same rate to ensure the reliability of the adjustment.

[0023] Furthermore, the heating device includes a first heating pipe and a heating mechanism, and the first heating pipe is provided with a heating mechanism; the cooling device includes a first cooling pipe, and one or more second cooling pipes are provided in the first cooling pipe, and a liquid is provided between the first cooling pipe and the second cooling pipe.

[0024] In the above setting, the cooling valve in the cooling pipe controls the gas in the main air pipe to enter the second cooling pipe. Since water is injected between the first cooling pipe and the second cooling pipe, when the gas passes through the second cooling pipe, it can be absorbed by the water in the first cooling pipe to complete the cooling of the gas. The cooled gas continues to flow downward into the main air pipe, and then enters the bottom diffusion plate from the main air pipe, thereby ensuring the cooling and heating effects.

[0025] Furthermore, a first flow pipe is provided on the lower side of the first cooling pipe, and a second flow pipe is provided on the upper side of the first cooling pipe. Both the first flow pipe and the second flow pipe are connected to the first cooling pipe.

[0026] The above arrangement, with the first circulation pipe connected to the water pipe and the second circulation pipe connected to another water pipe, allows water to enter the first cooling pipe from the first circulation pipe, and then be discharged through the second circulation pipe, thereby taking away the heat of the gas in the second cooling pipe through the circulating water.

[0027] Furthermore, an air collecting hood is provided between the upper end of the box body and the main air pipe, an exhaust fan is provided between the main air pipe and the air collecting hood, and a grille and a sponge column are provided on the main air pipe between the heating pipe and the cooling pipe.

[0028] In the above setting, the air collecting hood is used to concentrate the high-temperature gas in the box and introduce it into the main air duct, and an exhaust fan is provided between the main air duct and the air collecting hood, and the gas in the first cavity can be sucked into the main air duct through the exhaust fan. Due to the provision of the grille and the sponge column, the airflow will encounter resistance in the main air duct. If the valve device of the cooling pipe or the heating pipe is opened, the gas will pass through the cooling pipe or the heating pipe first, and the installation position of the grille and the sponge column is located between the heating pipe and the cooling pipe.

[0029] Furthermore, the bottom diffuser plate includes an outer diffuser plate and an inner diffuser plate, the outer diffuser plate is hollowed out, the outer diffuser plate is also provided with a second cavity and a first connecting hole, the first connecting hole is connected to the main air pipe, and each side wall of the second cavity is provided with more than one second connecting hole, the inner diffuser plate is connected to the outer diffuser plate through the second cavity, the inner diffuser plate is hollowed out, the inner diffuser plate is provided with an annular groove, the side of the annular groove close to the outer diffuser plate is the air inlet end, and the side of the annular groove away from the outer diffuser plate is the air outlet end, the outer side wall of the air inlet end of the inner diffuser plate is provided with a third connecting hole, and the third connecting hole is provided corresponding to the second connecting hole; the inner diffuser plate is provided with a third cavity, and the side wall of the third cavity is evenly provided with first perforations.

[0030] In the above arrangement, the first connecting hole is connected to the main air pipe. Since the outer diffuser is hollowed out internally, the gas can flow from the inside of the outer diffuser to the second connecting hole; the inner diffuser is connected to the outer diffuser through the second cavity, and a third connecting hole is provided on the outer wall of the air inlet end of the inner diffuser, which is connected to the second connecting hole through the third connecting hole, so that the gas of the outer diffuser flows to the inner diffuser, and the annular groove can be used to place the box. When the box is placed in the annular groove, the sealing between the inner diffuser and the box can be guaranteed; first perforations are evenly provided on the side wall of the third cavity. When the gas from the outer diffuser enters the inner diffuser through the second connecting hole, the gas in the inner diffuser can be evenly transported to the first cavity through the first perforation, thereby preventing local overheating or overcooling of the temperature in the box and ensuring the uniformity of the temperature in the box.

[0031] Furthermore, the heating pipe also includes a second heating pipe, a heating valve is provided on the second heating pipe, the heating valve includes a drive motor and a ball valve, the output shaft of the drive motor is connected to the ball valve, and the ball valve is matched with the second heating pipe. The cooling pipe also includes a third cooling pipe, a cooling valve is provided on the third cooling pipe, the cooling valve includes a drive motor and a ball valve, the output shaft of the drive motor is connected to the ball valve, and the ball valve is matched with the third cooling pipe.

[0032] With the above arrangement, when the gas needs to be heated, the drive motor drives the ball valve to rotate so that the gas in the main air pipe can enter the first heating pipe. When the heating temperature has reached the set temperature, the drive motor drives the ball valve to rotate so that the gas in the main air pipe cannot enter the first heating pipe. When the gas needs to be cooled, the drive motor drives the ball valve to rotate so that the gas in the main air pipe can enter the second cooling pipe. When the cooling temperature has reached the set temperature, the drive motor on the cooling pipe drives the ball valve to rotate so that the gas in the main air pipe cannot enter the second cooling pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is the front view of the present invention.

[0034] Figure 2 It is a cross-sectional view of the heating device in the present invention.

[0035] Figure 3 It is a front view of the valve device in the present invention.

[0036] Figure 4 It is the front view of the cooling device in the present invention.

[0037] Figure 5 This is an exploded view of the bottom diffusion plate in the present invention.

[0038] Figure 6 for Figure 5 Cross-section at AA in the middle.

[0039] Figure 7 for Figure 6 Enlarged view of point B in the middle.

[0040] Figure 8 The printed product of the present invention Figure 1 .

[0041] Figure 9 The printed product of the present invention Figure 2 .

[0042] Explanation of the accompanying numbers: 1-box; 2-heating tube; 21-first heating pipe; 22-heating plate; 23-second heating pipe; 3-cooling pipe; 31-first cooling pipe; 311-first circulation pipe; 312-second circulation pipe; 32-second cooling pipe; 33-third cooling pipe; 4-bottom diffusion plate; 41-outer diffusion plate; 411-first connecting hole; 412-second connecting hole; 413-second cavity; 42-inner diffusion plate; 421-third connecting hole; 422-first through-hole; 423-annular groove; 424-third cavity; 5-cooling valve; 51-drive motor; 52-ball valve; 06-heating valve; 6-main air pipe; 61-exhaust fan installation position; 62-grid and sponge column installation position; 63-temperature sensor installation position one; 64-temperature sensor installation position two; 7-gas collecting hood. DETAILED DESCRIPTION

[0043] Example 1.

[0044] like Figure 1-9As shown, a constant temperature control method for industrial additive manufacturing is controlled by an industrial additive manufacturing temperature control device, which includes a box 1, a first cavity is provided in the box 1, and a print head (not shown in the figure) is provided in the first cavity. The upper end of the box 1 is connected to one end of a main air pipe 6, the main air pipe 6 is connected to the first cavity, and the other end of the main air pipe 6 is connected to a bottom diffusion plate 4, which is connected to the first cavity. A heating pipe 2 and a cooling pipe 3 are provided along the main air pipe 6. The heating pipe 2 is provided with a heating device, which includes a first heating pipe 21 and a heating mechanism. The heating mechanism is provided on the outer surface of the first heating pipe 21.

[0045] A control module is also provided outside the industrial additive manufacturing temperature control device. The control module is any one of a PLC module, a single-chip microcomputer and a computer. The control module is the main control device for the operation of the industrial additive manufacturing temperature control device.

[0046] The cold air pipe is provided with a cooling device; the cooling device includes a first cooling pipe 31 , one or more second cooling pipes 32 are provided in the first cooling pipe 31 , and liquid is provided between the first cooling pipe 31 and the second cooling pipe 32 .

[0047] like Figure 1-2 As shown, an air collecting hood 7 is provided between the upper end of the box body 1 and the main air pipe 6, and an exhaust fan (not shown in the figure) is provided between the main air pipe 6 and the air collecting hood 7. The air collecting hood 7 is used to place consumables on the 3D printing equipment, and an exhaust fan (not shown in the figure) is provided between the main air pipe 6 and the air collecting hood 7. The gas in the first cavity can be sucked into the main air pipe 6 through the exhaust fan (not shown in the figure), wherein the exhaust fan installation position 61 is located between the main air pipe 6 and the air collecting hood 7.

[0048] A temperature sensor (not shown in the figure) is provided in the main air pipe 6. A temperature sensor is provided at one end of the main air pipe 6 close to the gas collecting hood 7, which can detect the gas temperature when it is input into the main air pipe 6. A temperature sensor (not shown in the figure) is provided at one end of the main air pipe 6 close to the bottom diffusion plate 4, which can detect the gas temperature when it is output from the main air pipe 6. The specific positions of the temperature sensors are temperature sensor installation position one 63 and temperature sensor installation position two 64.

[0049] A first circulation pipe 311 is provided on the lower side of the first cooling pipe 31, and a second circulation pipe 312 is provided on the upper side of the first cooling pipe 31. The first circulation pipe 311 and the second circulation pipe 312 are both connected to the first cooling pipe 31, and are connected to a water pipe through the first circulation pipe 311, and the second circulation pipe 312 is connected to another water pipe, so that water can enter the first cooling pipe 31 from the first circulation pipe 311, and then the water is discharged through the second circulation pipe 312, and then the heat of the gas in the second cooling pipe 32 is taken away by the circulating water.

[0050] The main air pipe 6 is located between the heating pipe 2 and the cooling pipe 3 and is provided with a grille (not shown in the figure) and a sponge column (not shown in the figure). Due to the provision of the grille (not shown in the figure) and the sponge column (not shown in the figure), the airflow will encounter resistance in the main air pipe 6. If the valve device 5 of the cooling pipe 3 or the heating pipe 2 is opened, the gas will preferentially pass through the cooling pipe 3 or the heating pipe 2, wherein the grille and sponge column installation position 62 is located between the heating pipe 2 and the cooling pipe 3.

[0051] The two ends of the first heating pipe 21 gradually narrow toward the middle to form an arc-shaped portion, and a heating disk 22 is sleeved on the outside of the arc-shaped portion. The two ends of the first heating pipe 21 gradually narrow toward the middle to form an arc-shaped portion, and the resistance disk is sleeved on the outside of the arc-shaped portion. The heating disk 22 heats the arc-shaped portion. When the gas passes through the first heating pipe 21, since the cross-sectional area of ​​the middle part of the first heating pipe 21 is smaller than the cross-sectional area of ​​the two ends, the gas flow rate increases at the arc-shaped portion, so that the gas quickly takes away the heat, and the heating disk 22 and the first heating pipe 21 are connected to prevent dust and impurities from accumulating on the heating disk 22.

[0052] The heating pipe 2 also includes a second heating pipe 23, which is provided with a heating valve 06. The heating valve 06 includes a drive motor 51 and a ball valve 52. The output shaft of the drive motor 51 is connected to the ball valve 52, and the ball valve 52 is matched with the second heating pipe 23. The cooling pipe 3 also includes a third cooling pipe 33. The third cooling pipe 33 is provided with a cooling valve 5. The cooling valve 5 includes a drive motor 51 and a ball valve 52. The output shaft of the drive motor 51 is connected to the ball valve 52, and the ball valve 52 is matched with the third cooling pipe 33.

[0053] With the above arrangement, when the gas needs to be heated, the drive motor 51 drives the ball valve 52 to rotate so that the gas in the main air pipe can enter the first heating pipe. When the heating temperature has reached the set temperature, the drive motor 51 drives the ball valve 52 to rotate so that the gas in the main air pipe cannot enter the first heating pipe. When the gas needs to be cooled, the drive motor 51 drives the ball valve 52 to rotate so that the gas in the main air pipe can enter the second cooling pipe 32. When the cooling temperature has reached the set temperature, the drive motor 51 on the cooling pipe drives the ball valve 52 to rotate so that the gas in the main air pipe cannot enter the second cooling pipe 32.

[0054] like Figure 5-7As shown, the bottom diffuser 4 includes an outer diffuser 41, which is hollowed out inside. The outer diffuser 41 is also provided with a second cavity 413 and a first connecting hole 411. The first connecting hole 411 is connected to the main air pipe 6. One or more second connecting holes 412 are provided on each side wall of the second cavity 413. The first connecting hole 411 is connected to the main air pipe 6. Since the outer diffuser 41 is hollowed out inside, the gas can flow from the inside of the outer diffuser 41 to the second connecting hole 412.

[0055] The bottom diffuser plate 4 also includes an inner diffuser plate 42, which is connected to the outer diffuser plate 41 through a second cavity 413. The inner diffuser plate 42 is hollowed out, and an annular groove 423 is provided on the inner diffuser plate 42. The side of the annular groove 423 close to the outer diffuser plate 41 is the air inlet end, and the side of the annular groove 423 away from the outer diffuser plate 41 is the air outlet end. The outer wall of the air inlet end of the inner diffuser plate 42 is provided with a third connecting hole 421, and the third connecting hole 421 is provided corresponding to the second connecting hole 412. The inner diffuser plate is connected to the outer diffuser plate 41 through the second cavity 413, and the third connecting hole 421 is provided on the outer wall of the air inlet end of the inner diffuser plate 42, which is connected to the second connecting hole 412 through the third connecting hole 421, so that the gas from the outer diffuser plate 41 flows to the inner diffuser plate 42, and the annular groove 423 can be used to place the box body 1. When the box body 1 is placed in the annular groove 423, the sealing between the inner diffuser plate 42 and the box body 1 can be ensured.

[0056] The inner diffusion disk 42 is provided with a third cavity 424, and the first perforations 422 are evenly provided on the side walls of the third cavity 424. When the gas from the outer diffusion disk 41 enters the inner diffusion disk 42 through the second connecting hole 412, the gas in the inner diffusion disk can be evenly transported to the first cavity through the first perforations 422, thereby preventing the temperature in the box body 1 from being locally overheated or overcooled, thereby ensuring the uniformity of the temperature in the box body 1.

[0057] When the industrial additive manufacturing temperature control device is used, by placing the box 1 in the annular groove 423, it can effectively isolate the interference of the external environment, ensure the uniformity and stability of the temperature in the cavity, and reduce the uneven shrinkage of the material caused by local temperature differences.

[0058] Example 2.

[0059] An industrial additive manufacturing temperature control method, comprising the following steps: , P heat P is the heating amount, print Because of the heat generated during printing, Dissipate heat to the environment, The heat provided to the heating valve, Heat dissipated by the cooling valve,

[0060] In this embodiment, the set time is 300 seconds, the target temperature is 450°C, the normal temperature is 25°C, the heat storage capacity of the box is 500, the heat generated under the standard film thickness of the printed product is 500w, and the heat generated if the film thickness is increased is 200w.

[0061] In the S1 heating stage, the temperature inside the box is heated to the target temperature and the feedforward heating demand is calculated. , where C is the heat storage capacity of the box, T set is the target temperature, T0 is the normal temperature, △t is the set time, and then calculate the heating valve opening ;

[0062] ,in The maximum heating power provided by the heating device is used to calculate the opening degree of the cooling valve. ;

[0063] ,in is the maximum heat dissipation power of the cooling device, P print To print heat power; adjust the heating valve opening from the preset opening size to the heating valve opening according to the preset rate ; Adjust the cooling valve opening from the closed state to the cooling valve open state according to the preset valve opening rate; in this embodiment, the heating valve opening: from 20% (i.e. the preset opening size) → 75%, the rate limit is Δuh / Δt≤0.5% / s; the cooling valve opening: from 0% → 5%, the rate is the same Δuc / Δt≤0.5% / s.

[0064] The default setting is to adjust the opening every 10 seconds.

[0065] During the steady-state control phase of S2 printing, the heating valve opening is determined based on the heat generated by the print head, the current opening of the cooling valve, the maximum heat generated by cooling, and the maximum heat generated by heating. ;

[0066] , where u c is the opening of the cooling valve, which is then adjusted through PID feedback. When the print head generates 500W power, the initial PID parameters are: Then, on this basis, the opening of the heating valve and the cooling valve are adjusted according to the PID algorithm. The specific PID algorithm is as follows:

[0067] ;

[0068] in For output, The current opening of the heating or cooling valve is an input.

[0069] If the film thickness exceeds the preset value (the film thickness can be detected by a film thickness detection device or by determining that the film thickness has exceeded the preset value when the preset film thickness is reached within a preset time period), the opening of the cooling valve is adjusted. ; In order to increase the heat generated by the print head when the film thickness is increased, that is, after the preset film thickness is reached, the initial opening of the cooling valve is adjusted from 5% to 13.3%. This increases the opening of the cooling valve, thereby improving the cooling effect of the cooling valve, thereby achieving rapid cooling when a large amount of heat is generated.

[0070] S3: Maintenance control phase after printing is completed, calculate the heat dissipation power , where T actual is the actual temperature, T ambient is the ambient temperature. These two temperatures can be measured by temperature sensors. loss For the preset heat dissipation coefficient, then calculate the heating valve opening At this time, close the cooling valve and rely on the heating valve to maintain the temperature.

[0071] In the non-printing state maintenance stage S4, the heating valve is completely closed. When the temperature rises back to the first high temperature value, such as 460°C, the cooling valve is opened at Δ uc ≤0.5% / s Open to 5%; when the temperature is lower than the second high temperature value such as 440℃, the heating valve is opened to Δ uh ≤0.5% / s Fine-tuning.

[0072] like Figure 8-9 As shown in the figure, the product produced after adjusting the above temperature control method has clear lines and no large-scale depressions, which makes the overall molding effect good and the temperature control effect good.

[0073] The working principle of the present invention is as follows: a first cavity is provided in the housing 1, and the first cavity can be used to place 3D printing equipment. A heating pipe 2 is provided on one side of the main gas pipe 6. When the temperature in the first cavity is lower than the set temperature, the valve device 5 in the heating pipe 2 controls the gas in the main gas pipe 6 to enter the first heating pipe 21. The heating device heats the gas in the first heating pipe 21, completing the heating of the gas. The heated gas continues to flow downward into the main gas pipe 6, and then enters the bottom diffusion plate 4 from the main gas pipe 6.

[0074] The cooling pipe 3 is provided with a first cooling pipe 31, and a plurality of second cooling pipes 32 are provided in the first cooling pipe 31. When the temperature in the first chamber is higher than the set temperature, the valve device 5 in the cooling pipe 3 controls the gas in the main air pipe 6 to enter the second cooling pipe 32. Since water is injected between the first cooling pipe 31 and the second cooling pipe 32, when the gas passes through the second cooling pipe 32, the heat is absorbed by the water in the first cooling pipe 31, completing the gas cooling. The cooled gas continues to flow downward into the main air pipe 6, and then enters the bottom diffuser 4 from the main air pipe 6.

[0075] The heated or cooled gas flows through the main gas pipe 6 to the bottom diffusion plate 4, and the gas flows from the bottom diffusion plate 4 to the first cavity to complete the temperature regulation of the box body 1; when the temperature does not need to be adjusted, the driving motor 51 controls the ball valve 52 so that the gas does not enter the heating tube 2 or the cooling tube 3.

[0076] During the temperature control process, in the heating stage, the feedforward heating demand is first determined by the difference between the target temperature and the actual temperature, and the opening of the heating valve is determined according to the feedforward heating demand, and the opening of the cooling valve is determined according to the heat generated by the print head and the maximum cooling temperature. The heating valve is then adjusted from the initial opening to the opening of the heating valve at a preset rate, and the cooling valve is adjusted from the closed state to the opening of the cooling valve at a preset speed. This ensures that the heating valve and the cooling valve are adjusted at a certain rate, and that the feedforward heating demand can be met after the heating valve is opened, so that there will be no linear temperature rise, and the temperature control in the heating stage is good. When printing in steady state, the feedforward heating valve opening is determined by the heat generated by the heating valve and the cooling temperature and maximum heating temperature generated by the cooling valve at the current opening. The opening of the heating valve is preliminarily determined, and then the dynamic openings of the heating valve and the cooling valve are adjusted by the PID algorithm, so that the preset temperature can be maintained reliably and stably in steady state. In addition, after the molding and printing process is completed, the cooling valve is closed and the opening of the heating valve is determined by the heat dissipation power to maintain a certain temperature of the box, so as to prevent direct cooling from causing the molded parts to go from a hot state to a cold state, thereby causing depressions in some parts and affecting the molding effect. In addition, when the non-printing state is maintained, the heating valve is directly closed to reduce energy consumption while ensuring the cooling effect of the molded product. By controlling different temperatures at different stages, good temperature control and molding effects are ensured.

[0077] When using this control method to print PEEK material, forced cooling can be avoided and the heating and cooling rates can be controlled, thereby avoiding forced cooling and effectively improving the crystallinity of the PEEK material, thereby significantly improving the hardness and strength of the PEEK material.

[0078] And controlling the heating and cooling rates can avoid stress concentration in the box, while also better maintaining the stability of the printed products, reducing warping and cracking of the printed products, and meeting the strict requirements of high-end application fields for printing quality.

Claims

1. A method for controlling temperature in industrial additive manufacturing, implemented by a temperature control device, the temperature control device comprising a housing, wherein a first cavity is provided within the housing, and wherein: The upper end of the box is connected to one end of the main air pipe, the main air pipe is connected to the first cavity, the other end of the main air pipe is connected to the bottom diffusion plate, the bottom diffusion plate is connected to the first cavity, a heating pipe and a cooling pipe are connected along the main air pipe, the heating pipe is provided with a heating device and a heating valve; the cooling pipe is provided with a cooling device and a cooling valve; a 3D printing nozzle is provided in the box; the specific steps include: S1 heating stage, according to the difference between the preset target temperature and the actual temperature, the box body heat storage capacity coefficient and the set time, the feedforward heating demand is calculated ; Then calculate the heating valve opening according to the feedforward heating demand and the maximum heating power of the heating device ; Adjust the heating valve opening from the preset opening size to the heating valve opening according to the preset rate ; Determine the cooling valve opening degree according to the heat generated by the print head, the maximum heat dissipation power of the cooling device, and the minimum value of the set opening degree; adjust the cooling valve opening degree from the closed state to the cooling valve opening degree according to the preset valve opening rate; During the steady-state control phase of S2 printing, the heating valve opening is determined based on the heat generated by the print head, the current opening of the cooling valve, the maximum heat generated by cooling, and the maximum heat generated by heating. ; Then, through PID feedback regulation, the cooling valve opening is adjusted according to the heat generated by the increased film thickness; S3: Maintenance control phase after printing is completed, calculate the heat dissipation power ; And determine the opening of the heating valve according to the heat dissipation power and the maximum heat generated by the heating valve and keep the cooling valve in the closed state; S4 non-printing state maintenance stage, the heating valve is closed at a preset rate; in step S1: feedforward heating demand , C is the preset box's heat storage capacity, T set is the target temperature, T0 is the normal temperature, △t is the set time; the heating valve opening ; The maximum heating power provided by the heating device, the cooling valve opening ; is the maximum heat dissipation power of the cooling device, P print is the heat generation power for printing; in step S2, the heating valve opening ; For heating heat, u c is the opening of the cooling valve, And step S2 also includes adjusting the opening of the cooling valve when the film thickness exceeds the preset value. ; The heat generated by the print head to increase the film thickness; in step S3 , T actual is the actual temperature, T ambient is the ambient temperature, k loss is the heat dissipation coefficient, and then calculate the heating valve opening , at this time, the cooling valve is closed and the temperature is maintained by the heating valve; step S4 also includes: when the temperature rises to the preset first high temperature value, the cooling valve is opened to 5% at a rate of Δuc≤0.5% / s; when the temperature is lower than the second high temperature value, the heating valve is adjusted at a rate of Δuh≤0.5% / s.

2. The industrial additive manufacturing temperature control method according to claim 1, characterized in that: The heating device includes a first heating pipe and a heating mechanism, and the heating mechanism is disposed on the outer shell of the first heating pipe; the cooling device includes a first cooling pipe, and one or more second cooling pipes are disposed inside the first cooling pipe, and liquid is disposed between the first cooling pipe and the second cooling pipe.

3. The industrial additive manufacturing temperature control method according to claim 2, characterized in that: A first flow pipe is provided at the lower side of the first cooling pipe, and a second flow pipe is provided at the upper side of the first cooling pipe. Both the first flow pipe and the second flow pipe are connected to the first cooling pipe.

4. The industrial additive manufacturing temperature control method according to claim 1, characterized in that: An air collecting hood is provided between the upper end of the box body and the main air pipe, an exhaust fan is provided between the main air pipe and the air collecting hood, and a grid and a sponge column are provided on the main air pipe between the heating pipe and the cooling pipe.

5. The industrial additive manufacturing temperature control method according to claim 1, characterized in that: The bottom diffuser plate includes an outer diffuser plate and an inner diffuser plate, the outer diffuser plate is hollowed out, the outer diffuser plate is further provided with a second cavity and a first connecting hole, the first connecting hole is connected to the main air pipe, and each side wall of the second cavity is provided with more than one second connecting hole; the inner diffuser plate is connected to the outer diffuser plate through the second cavity, the inner diffuser plate is hollowed out, the inner diffuser plate is provided with an annular groove, the side of the annular groove close to the outer diffuser plate is the air inlet end, and the side of the annular groove away from the outer diffuser plate is the air outlet end, the outer side wall of the air inlet end of the inner diffuser plate is provided with a third connecting hole, and the third connecting hole is provided corresponding to the second connecting hole; the inner diffuser plate is provided with a third cavity, and the side wall of the third cavity is evenly provided with first perforations.

6. The industrial additive manufacturing temperature control method according to claim 1, characterized in that: The heating pipe also includes a second heating pipe, which is provided with a heating valve. The heating valve includes a driving motor 1 and a ball valve 1. The output shaft of the driving motor 1 is connected to the ball valve 1. The ball valve 1 is matched with the second heating pipe. The cooling pipe also includes a third cooling pipe. The third cooling pipe is provided with a cooling valve. The cooling valve includes a driving motor 2 and a ball valve 2. The output shaft of the driving motor 2 is connected to the ball valve 2. The ball valve 2 is matched with the third cooling pipe.

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