Extrusion compensation method of extrusion wheel, 3D printer and electronic equipment

Abstract

The invention provides an extrusion compensation method of an extrusion wheel, a 3D printer and electronic equipment, the extrusion compensation method is suitable for the 3D printer, the 3D printer comprises the extrusion wheel and a hot end assembly, and the extrusion compensation method comprises the following steps: controlling the extrusion wheel to compensate under the compensation of a first compensation coefficient, and switching from a first extrusion speed to a second extrusion speed to extrude a printing material to the hot end assembly, obtaining a plurality of extrusion forces borne by the hot end assembly corresponding to the first compensation coefficient, and obtaining a target compensation coefficient of the extrusion wheel according to the plurality of extrusion forces borne by the hot end assembly corresponding to the first compensation coefficient. By implementing the method, the compensation coefficient in 3D printing is automatically measured, manual intervention is reduced, the efficiency is high, and the cost is low.

Description

[0001] This application claims the priority of the Chinese patent application filed with the China Patent Office on August 28, 2023, with application number 202311099096.7 and application name “An extrusion compensation method for an extrusion wheel, a 3D printer and an electronic device”, the entire contents of which are incorporated by reference in this application. Technical Field

[0002] The present application relates to the field of 3D printing technology, and in particular to an extrusion compensation method for an extrusion wheel, a 3D printer and an electronic device. Background Art

[0003] In the fused deposition modeling (FMD) 3D printing process, an extruder wheel in a 3D printer extrude printing material toward a hot end assembly, which heats the printing material to a molten state before flowing out.

[0004] Since the extrusion feeding process of the extrusion wheel is not completely rigid, when the extrusion speed of the extrusion wheel changes, the hot end component cannot achieve the desired flow rate change. Figure 1 As shown, when the extrusion speed of the extrusion wheel decreases, the flow rate of the hot end component is too fast, causing a large amount of printing material to accumulate in the low-speed area of ​​the print head movement and produce bulges; when the extrusion speed of the extrusion wheel increases, the flow rate of the hot end component is too slow, causing a lack of material in the high-speed area of ​​the print head movement and the formation of gaps.

[0005] To solve the above problems, the extrusion feed rate of an extrusion wheel can be increased or decreased according to the desired flow rate, that is, a compensation coefficient can be set for the extrusion wheel to quickly change the pressure of the hot melt cavity in the hot end component, thereby quickly changing the flow rate of the hot end component. Therefore, how to determine the compensation coefficient of the extrusion wheel is an issue that needs to be studied in depth. Summary of the invention

[0006] The present application provides an extrusion compensation method for an extrusion wheel, a 3D printer and an electronic device, which can automatically compensate the extrusion feed amount of the extrusion wheel without user intervention, with a high degree of automation and a high speed.

[0007] In a first aspect, an embodiment of the present application provides an extrusion compensation method for an extrusion wheel, the extrusion compensation method being applicable to a 3D printer, the 3D printer comprising an extrusion wheel and a hot end assembly, the extrusion compensation method comprising:

[0008] Controlling the extrusion wheel to switch from a first extrusion speed to a second extrusion speed to extrude the printing material toward the hot end assembly under the compensation of the first compensation coefficient;

[0009] Get multiple extrusion forces on the hot end component corresponding to the first compensation coefficient,

[0010] According to the multiple extrusion forces applied to the hot end component corresponding to the first compensation coefficient, a target compensation coefficient of the extrusion wheel is obtained.

[0011] The present application can automatically calibrate the compensation coefficient of the extrusion wheel, thereby realizing automatic compensation of the extrusion feeding amount of the extrusion wheel without user intervention, with high automation, high speed, high efficiency and low cost.

[0012] In combination with the first aspect, in a first possible implementation manner, obtaining a plurality of extrusion forces applied to the hot end assembly includes:

[0013] A plurality of extrusion forces to which the hot end assembly is subjected after the extrusion wheel switches the extrusion speed are obtained.

[0014] In combination with the first aspect or any one of the above possible implementations of the first aspect, in a second possible implementation, obtaining the target compensation coefficient of the extrusion wheel according to the multiple extrusion forces received by the hot end component corresponding to the first compensation coefficient includes:

[0015] Controlling the extrusion wheel to switch from a third extrusion speed to a fourth extrusion speed to extrude the printing material toward the hot end assembly under the compensation of the second compensation coefficient; wherein the third extrusion speed may be the first extrusion speed, and the fourth extrusion speed may be the second extrusion speed;

[0016] Acquire a plurality of extrusion forces exerted on the hot end component corresponding to the second compensation coefficient;

[0017] The target compensation coefficient of the extrusion wheel is obtained according to a plurality of extrusion forces received by the hot end component corresponding to the first compensation coefficient and a plurality of extrusion forces received by the hot end component corresponding to the second compensation coefficient.

[0018] The present application iterates the compensation coefficient, determines the target compensation coefficient of the extrusion wheel according to the multiple extrusion forces received by the hot end component corresponding to different compensation coefficients, and improves the accuracy of the target compensation coefficient.

[0019] In combination with the first aspect or any one of the above possible implementations of the first aspect, in a third possible implementation, the multiple extrusion forces applied to the hot end assembly include theoretical extrusion forces and actual extrusion forces;

[0020] The step of obtaining the target compensation coefficient of the extrusion wheel according to the multiple extrusion forces received by the hot end component corresponding to the first compensation coefficient and the multiple extrusion forces received by the hot end component corresponding to the second compensation coefficient includes:

[0021] Integrate the difference between the theoretical extrusion force and the actual extrusion force of the hot end component corresponding to the same compensation coefficient over time within the extrusion speed variation period of the extrusion wheel to obtain the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference of the hot end component corresponding to the second compensation coefficient;

[0022] The target compensation coefficient of the extrusion wheel is obtained according to the positive and negative relationship between the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient.

[0023] In the present application, considering the different materials, the different heating temperatures of the hot end assembly for the printing material, and the different apertures of the hot end assembly for the molten printing material, when the extrusion speed of the extrusion wheel changes, there is a difference between the actual extrusion force exerted by the printing material on the hot end assembly and the theoretical extrusion force. Therefore, the target compensation coefficient of the extrusion wheel can be calibrated based on the difference between the actual extrusion force exerted by the printing material on the hot end assembly and the theoretical extrusion force, with high accuracy.

[0024] In combination with the first aspect or any one of the foregoing possible implementations of the first aspect, in a fourth possible implementation, obtaining the target compensation coefficient of the extrusion wheel according to a positive and negative relationship between a flow difference of the hot end component corresponding to the first compensation coefficient and a flow difference corresponding to the second compensation coefficient includes:

[0025] When the flow difference of the hot end component corresponding to the first compensation coefficient is a positive number, and the flow difference of the hot end component corresponding to the second compensation coefficient is a negative number, the second compensation coefficient is used as the target compensation coefficient of the extrusion wheel. At this time, the first compensation coefficient is too small, and the second compensation coefficient is too large, that is, the second compensation coefficient is close to the expected value, and can be used as the target compensation coefficient of the extrusion wheel to improve the printing effect of the 3D printer.

[0026] In combination with the first aspect or any one of the foregoing possible implementations of the first aspect, in a fifth possible implementation, obtaining the target compensation coefficient of the extrusion wheel according to a positive and negative relationship between a flow difference of the hot end component corresponding to the first compensation coefficient and a flow difference corresponding to the second compensation coefficient includes:

[0027] When the flow difference of the hot end component corresponding to the first compensation coefficient is a negative number, and the flow difference of the hot end component corresponding to the second compensation coefficient is a positive number, the second compensation coefficient is used as the target compensation coefficient of the extrusion wheel. At this time, the first compensation coefficient is too large and the second compensation coefficient is too small, that is, the second compensation coefficient is close to the expected value, and can be used as the target compensation coefficient of the extrusion wheel to improve the printing effect of the 3D printer.

[0028] In combination with the first aspect or any one of the foregoing possible implementations of the first aspect, in a fifth possible implementation, obtaining the target compensation coefficient of the extrusion wheel according to a positive and negative relationship between a flow difference of the hot end component corresponding to the first compensation coefficient and a flow difference corresponding to the second compensation coefficient includes:

[0029] If the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient are both positive numbers, the second compensation coefficient is increased according to a first preset step size until the flow difference of the hot end component corresponding to the increased second compensation coefficient is a negative number, and the increased second compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

[0030] In the present application, the flow rate of the hot end component is changed by dynamically changing the compensation coefficient, which is simple to operate and highly efficient.

[0031] In combination with the first aspect or any one of the above possible implementations of the first aspect, in a seventh possible implementation, obtaining the target compensation coefficient of the extrusion wheel according to the positive and negative relationship between the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient includes:

[0032] If the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient are both negative, the second compensation coefficient is reduced according to a second preset step size until the flow difference of the hot end component corresponding to the reduced second compensation coefficient is a positive number, and the reduced second compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

[0033] In the present application, the flow rate of the hot end component is changed by dynamically changing the compensation coefficient, which is simple to operate and highly efficient.

[0034] In combination with the first aspect or any one of the above possible implementation methods of the first aspect, in a seventh possible implementation method, the extrusion speed change period of the extrusion wheel includes a first period and a second period; the theoretical extrusion force corresponding to each compensation coefficient includes a first theoretical extrusion force and a second theoretical extrusion force; the actual extrusion force corresponding to each compensation coefficient includes a first actual extrusion force and a second actual extrusion force.

[0035] The difference between the theoretical extrusion force and the actual extrusion force of the hot end component corresponding to the same compensation coefficient is integrated over time within the extrusion speed change period of the extrusion wheel to obtain the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference of the hot end component corresponding to the second compensation coefficient, including:

[0036] Integrate the difference between the first theoretical extrusion force corresponding to each compensation coefficient and the first actual extrusion force over time within the first period to obtain a first flow area difference corresponding to each compensation coefficient;

[0037] Integrate the difference obtained by subtracting the second theoretical extrusion force from the second actual extrusion force corresponding to each compensation coefficient over time within the second period to obtain a second flow area difference corresponding to each compensation coefficient;

[0038] The sum of the first flow area difference and the second flow area difference corresponding to each compensation coefficient is taken as the flow difference under each compensation coefficient.

[0039] This application obtains the flow area difference of each compensation coefficient during the acceleration of the extrusion wheel, and obtains the flow area difference of each compensation coefficient during the deceleration of the extrusion wheel. Taking the acceleration and deceleration processes of the extrusion wheel into consideration, the accuracy is further improved. In addition, the target compensation coefficient obtained in this application can be applied to different application scenarios of the extrusion wheel, especially in the right-angle process of the 3D printer, the extrusion wheel is decelerated in the horizontal direction and accelerated in the vertical direction, then the total speed of the extrusion wheel will present a process of acceleration, deceleration and then acceleration. In this process, the extrusion feed amount of the extrusion wheel can be compensated with a target compensation coefficient, without the need to frequently change the value of the compensation coefficient, and the reliability is high.

[0040] In combination with the first aspect or any one of the above possible implementations of the first aspect, in a ninth possible implementation, in the first period, the extrusion force corresponding to the first compensation coefficient increases from a first moment until it becomes stable at a second moment;

[0041] The first actual extrusion force corresponding to the first compensation coefficient is the extrusion force corresponding to the first compensation coefficient between the first moment and the second moment;

[0042] The first theoretical extrusion force corresponding to the first compensation coefficient is the extrusion force after the second moment in the first period.

[0043] In this application, the extruder wheel continues to increase the extruded printing material during the acceleration period, and the extrusion force on the hot end component continues to increase and then tends to be stable. The stable value is the theoretical extrusion force of the extruder wheel. At this time, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and high efficiency.

[0044] In combination with the first aspect or any one of the above possible implementations of the first aspect, in a tenth possible implementation, in the second period, the extrusion force corresponding to the first compensation coefficient decreases from the third moment until it becomes stable at the fourth moment;

[0045] The second actual extrusion force corresponding to the first compensation coefficient is the extrusion force corresponding to the first compensation coefficient between the third moment and the fourth moment;

[0046] The second theoretical extrusion force corresponding to the first compensation coefficient is the extrusion force after the fourth moment in the second period.

[0047] In this application, the extruder wheel continuously reduces the extruded printing material during the deceleration period, and the extrusion force on the hot end component continues to decrease and then tends to be stable. The stable value is the theoretical extrusion force of the extruder wheel. At this time, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and high efficiency.

[0048] In combination with the first aspect or any one of the above possible implementations of the first aspect, in an eleventh possible implementation, the extrusion wheel is connected to a motor;

[0049] The step of extruding the printing material toward the hot end assembly at different extrusion speeds comprises:

[0050] The motor is controlled to rotate at different speeds so that the extrusion wheel extrude the printing material toward the hot end assembly at different extrusion speeds.

[0051] The present application can realize the control of the extrusion speed of the extrusion wheel only by controlling the rotation speed of the motor, and has a high degree of automation.

[0052] In combination with the first aspect or any one of the above possible implementations of the first aspect, in a twelfth possible implementation, the 3D printer is provided with a bracket between the extrusion wheel and the hot end assembly, wherein the bracket is provided with a distance sensor on a side facing the hot end assembly;

[0053] The distance sensing device is used to sense the distance between the hot end assembly and the bracket to obtain the extrusion force exerted on the hot end assembly corresponding to the first compensation coefficient.

[0054] In the present application, the cost of measuring the extrusion force applied to the hot end assembly can be reduced, and the structure is simple and the space is compact.

[0055] In a second aspect, an embodiment of the present application provides a 3D printer, comprising a print head and a controller, the print head body being provided with an extrusion wheel and a hot end assembly, the controller being used to execute the extrusion compensation method described in combination with the first aspect or in combination with any one of the above possible implementations of the first aspect.

[0056] In a third aspect, an embodiment of the present application provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the extrusion compensation method described in combination with the first aspect or in combination with any one of the above possible implementation methods of the first aspect is implemented.

[0057] In a fourth aspect, an embodiment of the present application provides a computer program product, including a computer program, wherein the computer program, when executed by a processor, implements the extrusion compensation method described in combination with the first aspect or in combination with any one of the above possible implementation methods of the first aspect.

[0058] It should be understood that the implementation and beneficial effects of the above-mentioned aspects of the present application can be referenced to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A schematic diagram of an object printed by an existing 3D printer when the printing speed changes;

[0060] Figure 2 A schematic diagram of the structure of a 3D printer provided in an embodiment of the present application;

[0061] Figure 3 A schematic diagram of a flow chart of an extrusion compensation method for an extrusion wheel provided in an embodiment of the present application;

[0062] Figure 4 A schematic diagram of the structure of a print head provided in an embodiment of the present application;

[0063] Figure 5 Another structural schematic diagram of a print head provided in an embodiment of the present application;

[0064] Figure 6 A schematic diagram of a curve of the extrusion force applied to the hot end assembly provided in an embodiment of the present application;

[0065] Figure 7 A schematic diagram of a flow curve of a hot end assembly provided in an embodiment of the present application;

[0066] Figure 8 A schematic diagram of the flow area difference of the extrusion force provided in an embodiment of the present application;

[0067] Fig. 9 Another schematic flow chart of an extrusion compensation method for an extrusion wheel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0068] The implementation of the technical solution of the present application is further described in detail below in conjunction with the accompanying drawings.

[0069] See also Figure 2 , Figure 2A schematic diagram of the structure of a 3D printer provided in an embodiment of the present application. Figure 2 As shown, the 3D printer 102 is connected to the feeding device 101 .

[0070] The feeding device 101 may suspend a material tray in which printing material is wound. The feeding device 101 may provide the printing material to the 3D printer 102 .

[0071] The 3D printer 102 includes a print head 1021, wherein the print head 1021 includes a material guide unit 10211, a hot end assembly 10212, and an extrusion wheel disposed between the material guide unit 10211 and the hot end assembly 10212. During the feeding process of the feeding device 101, the printing material passes through the material guide unit 10211 and then enters the extrusion wheel, and the extrusion wheel provides the printing material to the hot end assembly 10212.

[0072] Exemplarily, the 3D printer 102 further includes a printing platform 1022 , and the hot end assembly 10212 can extrude the printing material in a molten state onto the printing platform 1022 .

[0073] In a specific implementation, the print head 1021 is slidably connected to the first guide rail 1023, and the print head 1021 can move along the length direction of the first guide rail 1023, that is, the print head 1021 is displaced relative to the printing platform 1022 along the length direction of the first guide rail 1023. The printing platform 1022 is slidably connected to the second guide rail 1024, and the printing platform 1022 moves along the length direction of the second guide rail 1024, that is, the print head 1021 is displaced relative to the printing platform 1022 along the length direction of the second guide rail 1024, and the length direction of the second guide rail 1024 is perpendicular to the length direction of the first guide rail 1023. In addition, the first guide rail 1023 is connected to the third guide rail 1025, and the 3D printer 102 can achieve the displacement of the print head 1021 relative to the printing platform 1022 in the direction perpendicular to the length of the second guide rail 1024 and the direction perpendicular to the length of the first guide rail 1023 by moving the first guide rail 1023 along the third guide rail 1025. That is, the 3D printer 102 can implement three printing paths in mutually perpendicular directions to print out a three-dimensional object.

[0074] In the present application, the compensation coefficient of the extrusion wheel is automatically calibrated to automatically compensate for the extrusion feed amount of the extrusion wheel, that is, to compensate for the printing material provided by the extrusion wheel to the hot end component, without user intervention, with high automation, high speed, high efficiency and low cost.

[0075] Combine the following Figures 3 to 9 The extrusion compensation method of the extrusion wheel provided in the present application is described in detail.

[0076] See also Figure 3, Figure 3 The following is a flow chart of an extrusion compensation method for an extrusion wheel provided in an embodiment of the present application. Figure 3 As shown, the extrusion compensation method of the extrusion wheel includes the following steps:

[0077] Step 301 : Control the extrusion wheel to switch from a first extrusion speed to a second extrusion speed to extrude printing material toward the hot end assembly under compensation of a first compensation coefficient.

[0078] Each step of the extrusion compensation method provided in the present application can be performed by one controller or multiple controllers with communication connection. Among them, the controller can be set on the print head of the 3D printer, the base connected to the second guide rail, or the base connected to the third guide rail. That is, the present application does not limit the number of controllers and the location where the controller is set.

[0079] Exemplarily, the controller can be, for example, a micro control unit (MCU), a central processing unit (CPU), other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0080] The extrusion wheel is connected to a motor, and the motor can rotate at different speeds according to different control signals sent by the controller, so that the extrusion wheel can extrude printing materials to the hot end assembly at different extrusion speeds. Exemplarily, the extrusion wheel is connected to the motor shaft of the motor, that is, the speed of the motor is related to the extrusion speed of the extrusion wheel, and the extrusion speed of the extrusion wheel can be switched by controlling the speed of the motor.

[0081] Step 302, obtaining multiple extrusion forces to which the hot end component is subjected corresponding to the first compensation coefficient. Optionally, information on the extrusion force to which the hot end component is subjected corresponding to the first compensation coefficient can be obtained from a measuring component, and the information on the extrusion force of the hot end component corresponding to the first compensation coefficient includes a theoretical extrusion force and an actual extrusion force corresponding to the first compensation coefficient. Exemplarily, the theoretical extrusion force can be a preset target value, and the actual extrusion force can be measured by the measuring component. Optionally, the measuring component includes a strain gauge or a distance sensor.

[0082] The different extrusion speeds of the extrusion wheel result in different pressures in the hot melt cavity of the hot end component, so that the extrusion forces on the hot end component are also different. In a specific implementation, the starting time when the hot end component is subjected to multiple extrusion forces corresponding to the first compensation coefficient is the time when the extrusion wheel switches the extrusion speed.

[0083] In some feasible implementations, the present application may use a cantilever surface strain method to measure the extrusion force on the hot end assembly. Figure 4 , Figure 4 A schematic diagram of the structure of a print head provided in an embodiment of the present application. Figure 4 As shown, the hot end assembly 43 is connected to one end of the strain cantilever 45, and the other end of the strain cantilever 45 is fixed. A strain gauge 44 is attached to the surface of the strain cantilever 45. When the extrusion wheel 41 squeezes the printing material 42 toward the hot end assembly 43, the extrusion force exerted by the printing material 42 on the hot end assembly 43 is transmitted to the strain cantilever 45, so that the surface of the strain cantilever 45 generates strain. At this time, the deformation of the surface of the strain cantilever 45 can be measured by the strain gauge 44. The deformation of the strain gauge 44 is associated with the extrusion force on the hot end assembly 43, and the extrusion force on the hot end assembly 43 can be further measured based on the deformation of the strain gauge 44.

[0084] Optionally, in some possible implementations, see Figure 5 , Figure 5 This is another structural schematic diagram of a print head provided in an embodiment of the present application. Figure 5 As shown, the print head body 500 is provided with an extrusion wheel 501 , a hot end assembly 502 , and a bracket 503 located between the extrusion wheel 501 and the hot end assembly 502 .

[0085] The bracket 503 is provided with a distance sensor 504 on the side facing the hot end assembly 502 . The distance sensor 504 can sense the distance between the hot end assembly 502 and the bracket 503 to obtain the extrusion force exerted by the printing material on the hot end assembly 502 .

[0086] Exemplarily, the hot end assembly 502 includes a heat sink fin 5021, a nozzle 5023, and a heating unit. The heating unit can be used to heat the printing material, and the printing material becomes a molten state and is extruded by the nozzle 5023.

[0087] The rigidity of the print head body 500 is within a certain range. Rigidity refers to the ability of a material or structure to resist elastic deformation when subjected to force, that is, the print head body 500 is not completely rigid. When the extrusion wheel 501 squeezes the printing material toward the hot end assembly 502, the nozzle 5023 in the hot end assembly 502 is subjected to the extrusion force, which drives the heat sink fin 5021 to move to the side away from the extrusion wheel 501, so that the distance between the hot end assembly 502 and the bracket 503 changes. The distance between the hot end assembly 502 and the bracket 503 is associated with the extrusion force applied by the printing material to the hot end assembly. After obtaining the distance between the hot end assembly 502 and the bracket 503, the extrusion force applied by the printing material to the hot end assembly 502 can be obtained by converting the distance and the extrusion force.

[0088] Optionally, the hot end assembly 502 may further include a silicone sleeve 5022, which is disposed around the heating unit to prevent heat loss from the heating unit and to prevent the user from being burned when accidentally touching the hot end assembly.

[0089] In the embodiment of the present application, a distance sensor device is added between the bracket and the hot end assembly. The distance between the hot end assembly and the bracket is sensed by the distance sensor device, and the extrusion force exerted by the printing material on the hot end assembly (i.e., the extrusion force exerted on the hot end assembly) is obtained. The structure is simple, the design flexibility is high, the space utilization rate is high, and the cost is low.

[0090] In some feasible implementations, the distance sensor device 504 includes a coil, and a plane where the coil is located is parallel to a surface of the heat sink fin 5021 .

[0091] For example, taking the first compensation coefficient as an example, under the compensation of the first compensation coefficient, the extrusion speed of the extrusion wheel is switched, and the multiple extrusion forces of the hot end component are measured as follows: Figure 6 As shown. Within the extrusion speed variation cycle T of the extruder wheel, the extrusion force f exerted on the hot end component is variable, which can be expressed as Figure 6 The solid line portion shown in FIG.

[0092] Optionally, the extrusion speed of the extrusion wheel is in the first period T1 (i.e., the first moment t 61 To the third moment t 63 ) increases. In the first cycle T1, the extrusion force f on the hot end component increases from the first moment t 61 Increases until the second moment t 62 tends to be stable. Then we can set 61 With the second moment t 62 The extrusion force f received by the hot end component during the first period T1 is taken as the first actual extrusion force received by the hot end component corresponding to the first compensation coefficient. 62Afterwards, at the second moment t 62 To the third moment t 63 The extrusion force f received by the hot end component at the second moment t is used as the first theoretical extrusion force F1 corresponding to the first compensation coefficient of the hot end component. 62 The stabilization can be understood as the second moment t 62 The extrusion force obtained by sampling and the second moment t 62 The magnitude of the extrusion force obtained at the previous sampling moment is within a preset range. 62 The extrusion force obtained by sampling and the second moment t 62 The extrusion forces sampled at the last sampling moment are equal in magnitude.

[0093] In this application, the extruder wheel continues to increase the extruded printing material during the acceleration period, and the extrusion force on the hot end component continues to increase and then tends to be stable. The stable value is the theoretical extrusion force of the extruder wheel. At this time, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and high efficiency.

[0094] Similarly, the extrusion speed of the extrusion wheel is in the second period T2 (i.e., the third moment t 63 To the fifth moment t 65 ) decreases. In the second period T2, the extrusion force f on the hot end assembly decreases from the third moment t 63 Decrease until the fourth moment t 64 tends to be stable. Then the third moment t 63 To the fourth moment t 64 The extrusion force f received by the hot end component during the period is taken as the second actual extrusion force received by the hot end component corresponding to the first compensation coefficient, and the extrusion force f received by the hot end component during the period T2 at the fourth time t 64 After that, at the fourth moment t 64 To the fifth moment t 65 The extrusion force f received by the hot end assembly during the fourth moment t is used as the second theoretical extrusion force F2 of the hot end assembly corresponding to the first compensation coefficient. 64 The stabilization can be understood as the fourth moment t 64 The extrusion force obtained by sampling and the fourth moment t 64 The magnitude of the extrusion force obtained at the last sampling moment is within a preset range. 64 The extrusion force obtained by sampling and the fourth moment t 64 The extrusion forces sampled at the last sampling moment are equal in magnitude. Figure 6Taking the example that the first theoretical extrusion force is greater than the first actual extrusion force and the second actual extrusion force is greater than the second theoretical extrusion force, optionally, the first theoretical extrusion force may be less than the first actual extrusion force, or the second actual extrusion force may be less than the second theoretical extrusion force.

[0095] Alternatively, the second theoretical extrusion force may be determined according to the first theoretical extrusion force, for example, the first theoretical extrusion force and the second theoretical extrusion force are in proportional relationship.

[0096] In this application, the extruder wheel continuously reduces the extruded printing material during the deceleration period, and the extrusion force on the hot end component continues to decrease and then tends to be stable. The stable value is the theoretical extrusion force of the extruder wheel. At this time, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and high efficiency.

[0097] Step 303, obtaining a target compensation coefficient of the extrusion wheel according to a plurality of extrusion forces received by the hot end component corresponding to the first compensation coefficient.

[0098] When the molten printing material flows out of the hot end assembly, the relationship between the flow rate of the hot end assembly and the pressure of the hot melt inner cavity of the hot end assembly can be expressed as:

[0099]

[0100] Among them, Q R is the flow rate of the hot end component, R is the small hole radius of the hot end component (i.e. the radius of the nozzle in the hot end component), ΔP is the pressure of the hot melt inner cavity of the hot end component, H is the constant coefficient, and L is the small hole length of the hot end component (i.e. the height of the conical part of the nozzle in the hot end component).

[0101] According to Formula 1, the pressure of the hot melt inner cavity of the hot end component is proportional to the flow rate of the hot end component.

[0102] Since the cross-sectional area of ​​the solid printing material is constant, the pressure in the hot melt cavity of the hot end component is proportional to the extrusion force exerted on the hot end component.

[0103] Therefore, the flow rate of the hot end component is proportional to the extrusion force on the hot end component. The flow curve of the hot end component can be as follows Figure 7 As shown, the flow curve of the hot end component is the same as the curve of the extrusion force applied to the hot end component.

[0104] In some feasible implementations, the difference between the theoretical extrusion force and the actual extrusion force corresponding to each compensation coefficient is integrated over time within the extrusion speed variation period of the extrusion wheel to obtain the flow difference under each compensation coefficient.

[0105] Combination Figure 6 and Figure 8It can be seen that in the first cycle T1, the first theoretical extrusion force corresponding to the first compensation coefficient is greater than the first actual extrusion force received by the hot end component, that is, in the first cycle, the hot end component is underextruded. At this time, the difference between the first theoretical extrusion force corresponding to the first compensation coefficient and the first actual extrusion force received by the hot end component is integrated over time in the first cycle to obtain the first flow area difference S1 corresponding to the first compensation coefficient, which can be expressed by the formula:

[0106]

[0107] In the second period T2, the second theoretical extrusion force corresponding to the first compensation coefficient is less than the second actual extrusion force received by the hot end component, that is, in the second period, the extrusion of the hot end component is too large. At this time, the difference obtained by subtracting the second theoretical extrusion force corresponding to the first compensation coefficient from the second actual extrusion force received by the hot end component is integrated over time in the second period to obtain the second flow area difference S2 corresponding to the first compensation coefficient, which can be expressed by the formula:

[0108]

[0109] At this time, the flow difference corresponding to the first compensation coefficient is the sum of the first flow area difference and the second flow area difference.

[0110] Combined with the previous article Figures 6 to 8 What is described is a method for calculating the flow difference of the first compensation coefficient among multiple compensation coefficients. The flow differences corresponding to the multiple compensation coefficients can be obtained by changing the size of the compensation coefficient in accordance with the method for calculating the flow difference of the first compensation coefficient as described above.

[0111] Optionally, in some feasible implementations, after obtaining the flow area difference, the flow volume may be further calculated to obtain the flow difference under each compensation coefficient.

[0112] Wherein, the target compensation coefficient of the extrusion wheel is obtained according to the flow difference of the hot end component at each compensation coefficient.

[0113] In some feasible implementations, after steps 301 to 303, the flow difference corresponding to the first compensation coefficient and the flow difference of the second compensation coefficient can be obtained, and the target compensation coefficient of the extrusion wheel can be obtained according to the positive and negative relationship between the flow difference of the hot end component under the first compensation coefficient and the flow difference under the second compensation coefficient. The present application selects the target compensation coefficient according to the positive and negative relationship between the two values, which is simple and effective, and can accurately obtain the target compensation coefficient of the extrusion wheel.

[0114] Optionally, in some feasible embodiments, since the flow rate of the hot end component is proportional to the extrusion force exerted on the hot end component, the target extrusion compensation coefficient of the extrusion wheel can be directly calculated according to the extrusion force based on the proportional relationship between the flow rate of the hot end component and the extrusion force exerted on the hot end component.

[0115] In some feasible implementations, the target compensation coefficient of the extrusion wheel may be obtained according to the theoretical extrusion force and the actual extrusion force corresponding to the hot end assembly and the first compensation coefficient.

[0116] For example, the target compensation coefficient of the extrusion wheel can be obtained by processing the first compensation coefficient based on the proportional relationship between the theoretical extrusion force and the actual extrusion force. That is, the target compensation coefficient and the first compensation coefficient can be in a linear multiple relationship. For example, the target compensation coefficient k can be expressed by the formula:

[0117]

[0118] Among them, k1 is the first compensation coefficient, F T1 is the theoretical extrusion force corresponding to the first compensation coefficient, F A1 is the actual extrusion force on the hot end component corresponding to the first compensation coefficient. If there are multiple extrusion forces on the hot end component corresponding to the first compensation coefficient, F A1 It can be the average or median of multiple extrusion forces.

[0119] Assuming that the first compensation coefficient k1=0.8, the theoretical extrusion force of the hot end component is 10N. The theoretical extrusion force can be a preset target value, but the actual extrusion force of the hot end component measured by the measuring component is 5N. At this time, according to Formula 4, the target compensation coefficient can be 1.6.

[0120] Alternatively, the target compensation coefficient of the extrusion wheel can be obtained by processing the first compensation coefficient based on the proportional relationship between the theoretical extrusion force and the actual extrusion force, and the positive correlation between the extrusion force and the flow rate. That is, the target compensation coefficient is positively correlated with the first compensation coefficient. For example, the target compensation coefficient k can be expressed by the formula:

[0121]

[0122] Among them, k1 is the first compensation coefficient, F T2 is the theoretical extrusion force corresponding to the first compensation coefficient, F A2 is the actual extrusion force on the hot end component corresponding to the first compensation coefficient. If there are multiple extrusion forces on the hot end component corresponding to the first compensation coefficient, F A2It can be the average or median of multiple extrusion forces. μ is the positive correlation coefficient between extrusion force and flow rate, which can be selected from a pre-set extrusion force and positive correlation coefficient mapping table based on the extrusion force F A2 Can be found.

[0123] Assuming that the first compensation coefficient k1=0.8, the theoretical extrusion force of the hot end component is 10N. The theoretical extrusion force can be a preset target value, but the actual extrusion force of the hot end component measured by the measuring component is 5N, μ=0.9. At this time, according to Formula 4, the target compensation coefficient can be 1.44.

[0124] In some feasible implementations, the following Fig. 9 The flowchart of the extrusion compensation method of the extrusion wheel is shown in the figure, which introduces how to determine the target compensation coefficient from multiple compensation coefficients. The specific steps are as follows:

[0125] Step 901: Set the current compensation coefficient C=C0.

[0126] Wherein, C0 can be understood as an initial compensation coefficient, which is a preset value. For example, the value of C0 can be 0; or it can be a value set based on experience to reduce the number of iterations.

[0127] Step 902: Control the extruder wheel to switch from the first extrusion speed to the second extrusion speed to extrude the printing material toward the hot end assembly. Figure 3 Step 301 in the described embodiment is not described in detail here.

[0128] Step 903: Obtain multiple extrusion forces. This step can be referred to in conjunction with the above Figures 3 to 5 Step 302 in the described embodiment is not described in detail here.

[0129] Step 904: Calculate the flow difference of the hot end component. This step can be referred to in conjunction with the above Figure 3 and Figure 6 Step 302 in the described embodiment is not described in detail here.

[0130] Step 905: Determine whether the flow difference value of the hot end component under the current compensation coefficient C and the flow difference value under the previous compensation coefficient are both positive or negative. If so, execute step 906b; otherwise, execute step 906a.

[0131] Exemplarily, when step 901 is executed for the first time, the operation starts with the initial compensation coefficient, and the previous compensation coefficient of the initial compensation coefficient does not exist or the previous compensation coefficient of the initial compensation coefficient is the initial compensation coefficient itself, and step 906b is executed at this time. Then step 907a or 907b is executed.

[0132] Step 906a: Use the current compensation coefficient C as the target compensation coefficient of the extrusion wheel.

[0133] The flow difference of the hot end component under the current compensation coefficient C is a positive number, and the flow difference of the hot end component under the previous compensation coefficient of the current compensation coefficient is a negative number, indicating that the current compensation coefficient C (i.e., the second compensation coefficient) is too small, and the previous compensation coefficient of the current compensation coefficient (i.e., the first compensation coefficient) is too large. At this time, the second compensation coefficient is close to the expected value and can be used as the target compensation coefficient of the extrusion wheel to improve the printing effect of the 3D printer. Alternatively, the first compensation coefficient can also be used as the target compensation coefficient of the extrusion wheel.

[0134] Alternatively, the flow difference of the hot end component under the current compensation coefficient C is a negative number, and the flow difference of the hot end component under the previous compensation coefficient of the current compensation coefficient is a positive number, indicating that the current compensation coefficient C (i.e., the second compensation coefficient) is too large, and the previous compensation coefficient of the current compensation coefficient (i.e., the first compensation coefficient) is too small. At this time, the second compensation coefficient is close to the expected value and can be used as the target compensation coefficient of the extrusion wheel to improve the printing effect of the 3D printer. Alternatively, the first compensation coefficient can also be used as the target compensation coefficient of the extrusion wheel.

[0135] Step 906b: determine whether the flow difference value of the hot end component under the current compensation coefficient C and the flow difference value under the previous compensation coefficient are both positive. If so, execute step 907a; otherwise, execute step 907b.

[0136] Step 907a, C=C+0.001. The value of the flow difference of the hot end component under the current compensation coefficient C and the value of the flow difference under the previous compensation coefficient are both positive numbers, indicating that the current compensation coefficient C (i.e., the second compensation coefficient) and the previous compensation coefficient of the current compensation coefficient (i.e., the first compensation coefficient) are too small, and the second compensation coefficient is increased according to the first preset step size, and then steps 901 to 905 are repeated until the value of the flow difference of the hot end component under the second compensation coefficient is different from the value of the flow difference under the first compensation coefficient. The second compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

[0137] Fig. 9 Taking the first preset step size of 0.001 as an example, the first preset step size can also be set to other values, and this application does not limit the value of the first preset step size.

[0138] Step 907b, C=C-0.001. The value of the flow difference of the hot end component under the current compensation coefficient C and the value of the flow difference under the previous compensation coefficient are both negative numbers, indicating that the current compensation coefficient C (i.e., the second compensation coefficient) and the previous compensation coefficient of the current compensation coefficient (i.e., the first compensation coefficient) are too large, and the second compensation coefficient is reduced according to the second preset step size. Then, steps 901 to 905 are repeated until the value of the flow difference of the hot end component under the second compensation coefficient is different from the value of the flow difference under the first compensation coefficient, and the second compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

[0139] Fig. 9 Taking the second preset step size of 0.001 as an example, the second preset step size can be equal to the first preset step size, or can be set to other values. This application does not limit the value of the second preset step size.

[0140] In the present application, the flow difference of the hot end component is changed by dynamically changing the compensation coefficient, so that the hot end component can be dynamically compensated for flow during the 3D printing process, which is simple to operate and highly efficient.

[0141] In some feasible implementations, the present application further provides a 3D printer, the 3D printer is provided with a print head and a controller, the print head body is provided with an extrusion wheel and a hot end assembly, and the controller can execute the above-mentioned combination Figures 3 to 9 The described embodiments thus achieve dynamic flow compensation of the 3D printer and improve the printing effect of the 3D printer.

[0142] An embodiment of the present application further provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned Figures 3 to 9 Embodiment described.

[0143] An embodiment of the present application further provides a computer program product, including a computer program, wherein the computer program implements the above-mentioned Figures 3 to 9 Embodiment described.

[0144] It should be noted that the above terms “first” and “second” are only used for descriptive purposes and should not be understood as indicating or implying relative importance.

Claims

1. An extrusion compensation method for an extrusion wheel, characterized in that: The extrusion compensation method is applicable to a 3D printer, wherein the 3D printer comprises an extrusion wheel and a hot end assembly, and the 3D printer is provided with a measuring assembly for measuring the extrusion force exerted on the hot end assembly; the extrusion compensation method comprises: Controlling the extrusion wheel to switch from a first extrusion speed to a second extrusion speed to extrude printing material toward the hot end assembly under compensation of a first compensation coefficient; Acquiring information about the extrusion force exerted on the hot end component corresponding to the first compensation coefficient from the measuring component; The target compensation coefficient of the extrusion wheel is obtained according to the information of the extrusion force exerted on the hot end component corresponding to the first compensation coefficient.

2. The extrusion compensation method according to claim 1, characterized in that: The method further comprises: Controlling the extrusion wheel to switch from the third extrusion speed to the fourth extrusion speed to extrude the printing material toward the hot end assembly under the compensation of the second compensation coefficient; Acquiring information about the extrusion force exerted on the hot end component corresponding to the second compensation coefficient from the measuring component; The target compensation coefficient of the extrusion wheel is obtained according to the information of the extrusion force received by the hot end component corresponding to the first compensation coefficient and the information of the extrusion force received by the hot end component corresponding to the second compensation coefficient.

3. The extrusion compensation method according to claim 2, characterized in that: The step of obtaining the target compensation coefficient of the extrusion wheel according to the information of the extrusion force received by the hot end component corresponding to the first compensation coefficient and the information of the extrusion force received by the hot end component corresponding to the second compensation coefficient includes: Integrate the difference between the theoretical extrusion force and the actual extrusion force of the hot end component corresponding to the same compensation coefficient over time within the extrusion speed variation period of the extrusion wheel to obtain the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference of the hot end component corresponding to the second compensation coefficient; The target compensation coefficient of the extrusion wheel is obtained according to the positive and negative relationship between the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient.

4. The extrusion compensation method according to claim 3, characterized in that: The step of obtaining the target compensation coefficient of the extrusion wheel according to the positive and negative relationship between the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient comprises: When the flow difference of the hot end component corresponding to the first compensation coefficient is a positive number and the flow difference of the hot end component corresponding to the second compensation coefficient is a negative number, the second compensation coefficient or the first compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

5. The extrusion compensation method according to claim 3, characterized in that: The step of obtaining the target compensation coefficient of the extrusion wheel according to the positive and negative relationship between the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient comprises: When the flow difference of the hot end component corresponding to the first compensation coefficient is a negative number and the flow difference of the hot end component corresponding to the second compensation coefficient is a positive number, the second compensation coefficient or the first compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

6. The extrusion compensation method according to any one of claims 3 to 5, characterized in that: The step of obtaining the target compensation coefficient of the extrusion wheel according to the positive and negative relationship between the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient comprises: If the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient are both positive numbers, the second compensation coefficient is increased until the flow difference of the hot end component corresponding to the increased second compensation coefficient is negative, and the increased second compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

7. The extrusion compensation method according to any one of claims 3 to 5, characterized in that: The step of obtaining the target compensation coefficient of the extrusion wheel according to the positive and negative relationship between the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient comprises: If the flow difference of the hot end component corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient are both negative, the second compensation coefficient is reduced until the flow difference of the hot end component corresponding to the reduced second compensation coefficient is a positive number, and the reduced second compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

8. The extrusion compensation method according to any one of claims 3 to 5, characterized in that: The theoretical extrusion force corresponding to each compensation coefficient includes a first theoretical extrusion force and a second theoretical extrusion force; The actual extrusion force corresponding to each compensation coefficient includes a first actual extrusion force and a second actual extrusion force; The method further comprises: Controlling the extrusion wheel under the compensation of the first compensation coefficient, the extrusion speed change of the extrusion wheel includes speed increase and speed decrease, and the extrusion speed change cycle of the extrusion wheel includes a first cycle of speed increase and a second cycle of speed decrease; Integrate the difference between the first theoretical extrusion force corresponding to each compensation coefficient and the first actual extrusion force over time within the first period to obtain a first flow area difference corresponding to each compensation coefficient; Integrate the difference obtained by subtracting the second theoretical extrusion force from the second actual extrusion force corresponding to each compensation coefficient over time within the second period to obtain a second flow area difference corresponding to each compensation coefficient; According to the first flow area difference and the second flow area difference corresponding to each compensation coefficient, the flow difference under each compensation coefficient is obtained.

9. The extrusion compensation method according to claim 8, characterized in that: In the first period, the extrusion force corresponding to the first compensation coefficient increases from a first moment until it becomes stable at a second moment; The first actual extrusion force corresponding to the first compensation coefficient is the extrusion force corresponding to the first compensation coefficient between the first moment and the second moment; The first theoretical extrusion force corresponding to the first compensation coefficient is the extrusion force after the second moment in the first period.

10. The extrusion compensation method according to claim 8, characterized in that: In the second period, the extrusion force corresponding to the first compensation coefficient decreases from the third moment until it becomes stable at the fourth moment; The second actual extrusion force corresponding to the first compensation coefficient is the extrusion force corresponding to the first compensation coefficient between the third moment and the fourth moment; The second theoretical extrusion force corresponding to the first compensation coefficient is the extrusion force after the fourth moment in the second period.

11. The extrusion compensation method according to claim 1, characterized in that: The measuring component comprises a strain gauge or a distance sensing device.

12. The extrusion compensation method according to any one of claims 1 to 11, characterized in that: The 3D printer is provided with a bracket between the extrusion wheel and the hot end assembly, and the measuring assembly comprises a distance sensor device arranged on a side of the bracket facing the hot end assembly; The distance sensing device is used to sense the distance between the hot end assembly and the bracket.

13. The extrusion compensation method according to any one of claims 1 to 11, characterized in that: The hot end assembly is connected to the strain cantilever, and the measuring assembly includes a strain gauge attached to the surface of the strain cantilever; The strain gauge is used to measure the deformation of the surface of the strain cantilever.

14. A 3D printer, characterized in that: The 3D printer comprises a print head and a controller, wherein the print head body is provided with an extrusion wheel and a hot end assembly, and the controller is used to execute the extrusion compensation method as claimed in any one of claims 1 to 13.

15. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the extrusion compensation method for an extrusion wheel according to any one of claims 1 to 13 is implemented.

16. A computer program product, characterized in that The invention comprises a computer program, wherein when the computer program is executed by a processor, the computer program implements the extrusion compensation method of the extrusion wheel according to any one of claims 1 to 13.

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