Extrusion compensation method for extrusion wheel, 3D printer, and electronic device

Abstract

The present application provides an extrusion compensation method for an extrusion wheel, a 3D printer, and an electronic device. The extrusion compensation method is suitable for a 3D printer, and the 3D printer comprises an extrusion wheel and a hot end assembly. The extrusion compensation method comprises: controlling an extrusion wheel to switch from a first extrusion speed to a second extrusion speed under the compensation of a first compensation coefficient to extrude a printing material to a hot end assembly; acquiring a plurality of extrusion forces applied to the hot end assembly under the first compensation coefficient; and on the basis of the plurality of extrusion forces applied to the hot end assembly under the first compensation coefficient, obtaining a target compensation coefficient of the extrusion wheel. By means of the present application, a compensation coefficient in 3D printing is automatically measured, manual intervention is reduced, the efficiency is high, and the cost is low.

Description

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

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on August 28, 2023, with application number 202311099096.7 and application name “A method for extrusion compensation of an extrusion wheel, a 3D printer and an electronic device”, the entire contents of which are incorporated by reference into 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] During the fused deposition modeling (FMD) 3D printing process, an extruder wheel in the 3D printer extrude printing material toward a hot end assembly, which heats the printing material to a molten state before flowing out.

[0004] Because the extrusion wheel's extrusion feeding process isn't completely rigid, the hot-end assembly can't achieve the desired flow rate change when the extrusion wheel's extrusion speed changes. For example, as shown in Figure 1, when the extrusion wheel's extrusion speed decreases, the hot-end assembly's flow rate is too high, causing a large amount of printing material to accumulate in the slow-moving areas of the print head, resulting in bulges. When the extrusion wheel's extrusion speed increases, the hot-end assembly's flow rate is too slow, causing material to be scarce in the high-speed areas of the print head, resulting in gaps.

[0005] To address this issue, the extrusion feed rate of an extruder wheel can be increased or decreased based on the desired flow rate. This means setting a compensation coefficient for the extruder wheel to rapidly change the pressure within the hot melt cavity of the hot end assembly, thereby rapidly changing the flow rate of the hot end assembly. Therefore, determining the compensation coefficient for the extruder wheel is a key issue that requires significant research.

[0006] Summary of the Invention

[0007] The present application provides an extrusion compensation method for an extrusion wheel, a 3D printer, and an electronic device, which can automatically compensate for the extrusion feed amount of the extrusion wheel without user intervention, with a high degree of automation and high speed.

[0008] In a first aspect, an embodiment of the present application provides an extrusion compensation method for an extrusion wheel, wherein the extrusion compensation method is applicable to a 3D printer including an extrusion wheel and a hot end assembly, and the extrusion compensation method includes:

[0009] 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;

[0010] Get multiple extrusion forces on the hot end component corresponding to the first compensation coefficient,

[0011] 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.

[0012] The present application can automatically calibrate the compensation coefficient of the extrusion wheel, thereby automatically compensating the extrusion feed amount of the extrusion wheel without user intervention, with high automation, high speed, high efficiency and low cost.

[0013] In combination with the first aspect, in a first possible implementation manner, obtaining the multiple extrusion forces applied to the hot end assembly includes:

[0014] A plurality of extrusion forces applied to the hot end assembly after the extrusion wheel switches the extrusion speed are obtained.

[0015] In combination with the first aspect or any one of the foregoing 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 applied to the hot end assembly corresponding to the first compensation coefficient includes:

[0016] 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 compensation by a 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;

[0017] obtaining a plurality of extrusion forces exerted on the hot end component corresponding to the second compensation coefficient;

[0018] A 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.

[0019] This 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.

[0020] In combination with the first aspect or any one of the foregoing possible implementations of the first aspect, in a third possible implementation, the multiple extrusion forces applied to the hot end assembly include a theoretical extrusion force and an actual extrusion force;

[0021] 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:

[0022] Integrating 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;

[0023] 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.

[0024] In this application, the difference between the actual and theoretical extrusion forces exerted by the hot end assembly due to variations in material, the temperature at which the hot end assembly heats the printed material, and the diameter of the pores through which the molten printed material flows is taken into account. This difference in the actual and theoretical extrusion forces exerted by the printed material on the hot end assembly can be used to accurately calibrate the target compensation coefficient for the extrusion wheel.

[0025] 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 based on a positive and negative relationship between a flow rate difference of the hot end component corresponding to the first compensation coefficient and a flow rate difference corresponding to the second compensation coefficient includes:

[0026] When the flow rate difference of the hot end assembly corresponding to the first compensation coefficient is positive, and the flow rate difference of the hot end assembly corresponding to the second compensation coefficient is negative, the second compensation coefficient is used as the target compensation coefficient for the extruder. In this case, 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 desired value and can be used as the target compensation coefficient for the extruder, thereby improving the printing effect of the 3D printer.

[0027] 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 based on a positive and negative relationship between a flow rate difference of the hot end component corresponding to the first compensation coefficient and a flow rate difference corresponding to the second compensation coefficient includes:

[0028] When the flow rate difference of the hot end assembly corresponding to the first compensation coefficient is negative, and the flow rate difference of the hot end assembly corresponding to the second compensation coefficient is positive, the second compensation coefficient is used as the target compensation coefficient for the extruder. In this case, 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 desired value and can be used as the target compensation coefficient for the extruder, thereby improving the printing effect of the 3D printer.

[0029] 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 based on a positive and negative relationship between a flow rate difference of the hot end component corresponding to the first compensation coefficient and a flow rate difference corresponding to the second compensation coefficient includes:

[0030] 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, 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 negative, and the increased second compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

[0031] 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.

[0032] In combination with the first aspect or any one of the foregoing possible implementations of the first aspect, in a seventh possible implementation, obtaining the target compensation coefficient of the extrusion wheel based on a positive and negative relationship between a flow rate difference of the hot end component corresponding to the first compensation coefficient and a flow rate difference corresponding to the second compensation coefficient includes:

[0033] 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 positive, and the reduced second compensation coefficient is used as the target compensation coefficient of the extrusion wheel.

[0034] 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.

[0035] 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.

[0036] 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:

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

[0038] Integrating a 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;

[0039] The sum of the first flow area difference and the second flow area difference corresponding to each compensation coefficient is used as the flow difference under each compensation coefficient.

[0040] The present application obtains the flow area difference of each compensation coefficient during the acceleration process of the extrusion wheel, and obtains the flow area difference of each compensation coefficient during the deceleration process of the extrusion wheel. Taking into account the acceleration and deceleration process of the extrusion wheel, the accuracy is further improved. In addition, the target compensation coefficient obtained in the present 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 show 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.

[0041] In combination with the first aspect or any one of the foregoing possible implementations of the first aspect, in a ninth possible implementation, during 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.

[0042] 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;

[0043] The first theoretical extrusion force corresponding to the first compensation coefficient is the extrusion force after the second moment in the first period.

[0044] In this application, the extruder wheel continuously extrudes more printing material during the acceleration period, and the extrusion force on the hot end assembly continues to increase and then stabilizes. The value at which it stabilizes is the theoretical extrusion force of the extruder wheel. In this case, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and improving efficiency.

[0045] In combination with the first aspect or any one of the foregoing possible implementations of the first aspect, in a tenth possible implementation, during 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.

[0046] 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;

[0047] The second theoretical extrusion force corresponding to the first compensation coefficient is the extrusion force after the fourth moment in the second period.

[0048] In this application, the extruder wheel continuously reduces the amount of extruded printing material during the deceleration period, and the extrusion force on the hot end assembly continuously decreases and then stabilizes. The value at which it stabilizes is the theoretical extrusion force of the extruder wheel. In this case, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and improving efficiency.

[0049] In combination with the first aspect or any one of the foregoing possible implementations of the first aspect, in an eleventh possible implementation, the extrusion wheel is connected to a motor;

[0050] The step of extruding the printing material toward the hot end assembly at different extrusion speeds comprises:

[0051] The motor is controlled to rotate at different speeds so that the extrusion wheel extrude printing material toward the hot end assembly at different extrusion speeds.

[0052] The present application only needs to control the rotation speed of the motor to realize the control of the extrusion speed of the extrusion wheel, and the degree of automation is high.

[0053] In combination with the first aspect or any one of the foregoing 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;

[0054] 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.

[0055] In the present application, the cost of measuring the extrusion force exerted on the hot end component can be reduced, and the structure is simple and the space is compact.

[0056] In a second aspect, an embodiment of the present application provides a 3D printer, comprising 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 described in combination with the first aspect or in combination with any one of the above possible implementation methods of the first aspect.

[0057] In a third aspect, an embodiment of the present application provides a computer-readable storage medium storing a computer program, which, 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-mentioned possible implementation methods of the first aspect.

[0058] In a fourth aspect, an embodiment of the present application provides a computer program product, comprising a computer program, wherein, 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-mentioned possible implementation methods of the first aspect is implemented.

[0059] 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

[0060] FIG1 is a schematic diagram of an object printed by a conventional 3D printer when the printing speed is varied;

[0061] FIG2 is a schematic structural diagram of a 3D printer provided in an embodiment of the present application;

[0062] FIG3 is a schematic flow chart of an extrusion compensation method for an extrusion wheel provided in an embodiment of the present application;

[0063] FIG4 is a schematic structural diagram of a print head provided in an embodiment of the present application;

[0064] FIG5 is another schematic diagram of the structure of a print head provided in an embodiment of the present application;

[0065] FIG6 is a schematic diagram of a curve showing the extrusion force applied to the hot end assembly according to an embodiment of the present application;

[0066] FIG7 is a schematic diagram of a flow curve of a hot end assembly provided in an embodiment of the present application;

[0067] FIG8 is a schematic diagram of the flow area difference of the extrusion force provided in an embodiment of the present application;

[0068] FIG9 is another schematic flow chart of an extrusion compensation method for an extrusion wheel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0069] The implementation of the technical solution of the present application is further described in detail below with reference to the accompanying drawings.

[0070] 2 , which is a schematic diagram of a 3D printer according to an embodiment of the present application, as shown in FIG2 , a 3D printer 102 is connected to a feeding device 101 .

[0071] The feeding device 101 can suspend a material tray with printing material wound around it and can provide the printing material to the 3D printer 102 .

[0072] 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 extruder 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 extruder wheel, which then supplies the printing material to the hot end assembly 10212.

[0073] Exemplarily, the 3D printer 102 further includes a printing platform 1022 , and the hot end assembly 10212 can extrude molten printing material onto the printing platform 1022 .

[0074] In a specific implementation, the print head 1021 is slidably connected to the first guide rail 1023, allowing it to move along the length of the first guide rail 1023. This allows the print head 1021 to be displaced relative to the printing platform 1022 along the length of the first guide rail 1023. The printing platform 1022 is slidably connected to the second guide rail 1024, allowing it to move along the length of the second guide rail 1024. This allows the print head 1021 to be displaced relative to the printing platform 1022 along the length of the second guide rail 1024. The length of the second guide rail 1024 is perpendicular to the length of the first guide rail 1023. Furthermore, the first guide rail 1023 is connected to the third guide rail 1025. By moving the first guide rail 1023 along the third guide rail 1025, the 3D printer 102 can displace the print head 1021 relative to the printing platform 1022 in directions perpendicular to the lengths of the second guide rail 1024 and the first guide rail 1023. That is, the 3D printer 102 can implement three mutually perpendicular printing paths to print out a three-dimensional object.

[0075] In this application, by automatically calibrating the compensation coefficient of the extrusion wheel, the extrusion feed amount of the extrusion wheel is automatically compensated, that is, the printing material provided by the extrusion wheel to the hot end component is compensated without user intervention, with high degree of automation, high speed, high efficiency and low cost.

[0076] The extrusion compensation method of the extrusion wheel provided in the present application is described in detail below with reference to FIG. 3 to FIG. 9 .

[0077] Referring to Figure 3, Figure 3 is a schematic flow chart of an extrusion compensation method for an extrusion wheel provided in an embodiment of the present application. As shown in Figure 3, the extrusion compensation method for an extrusion wheel includes the following steps:

[0078] Step 301 : Control the extrusion wheel to switch from a first extrusion speed to a second extrusion speed under compensation of a first compensation coefficient to extrude printing material toward the hot end assembly.

[0079] Each step of the extrusion compensation method provided herein can be performed by a single controller or multiple controllers with a communication connection. The controller can be located on the print head of the 3D printer, on the base connected to the second guide rail, or on the base connected to the third guide rail. This application does not limit the number of controllers or their locations.

[0080] 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.

[0081] The extrusion wheel is connected to a motor, which can rotate at different speeds according to different control signals sent by the controller, so that the extrusion wheel can extrude printing material toward the hot end assembly at different extrusion speeds. For example, the extrusion wheel is connected to the motor shaft of the motor, that is, the speed of the motor is correlated with the extrusion speed of the extrusion wheel. The extrusion speed of the extrusion wheel can be switched simply by controlling the speed of the motor.

[0082] Step 302: Obtain multiple extrusion forces applied to the hot-end assembly corresponding to a first compensation coefficient. Optionally, information about the extrusion forces applied to the hot-end assembly corresponding to the first compensation coefficient can be obtained from a measurement assembly. The information about the extrusion forces applied to the hot-end assembly 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 pre-set target value, and the actual extrusion force can be measured by the measurement assembly. Optionally, the measurement assembly includes a strain gauge or a distance sensor.

[0083] Different extrusion wheel extrusion speeds result in different pressures in the hot melt cavity of the hot end assembly, resulting in different extrusion forces on the hot end assembly. In a specific implementation, the starting time for obtaining the first compensation coefficient corresponding to the hot end assembly being subjected to multiple extrusion forces is the time when the extrusion wheel switches the extrusion speed.

[0084] In some feasible embodiments, the present application may use a cantilever surface strain method to measure the extrusion force exerted on the hot end assembly. Referring to Figure 4, Figure 4 is a schematic structural diagram of a print head provided in an embodiment of the present application. As shown in Figure 4, the hot end assembly 43 is connected to one end of a 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, causing strain to be generated on the surface of the strain cantilever 45. 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 exerted on the hot end assembly 43, and the extrusion force exerted on the hot end assembly 43 can be further measured based on the deformation of the strain gauge 44.

[0085] Alternatively, in some feasible embodiments, see Figure 5 , which is another schematic diagram of the structure of a print head provided in an embodiment of the present application. As shown in Figure 5 , a print head body 500 includes 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 .

[0086] 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 .

[0087] For example, 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 is extruded from the nozzle 5023 after it becomes molten.

[0088] The stiffness of the print head body 500 is within a certain range. Stiffness 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 fins 5021 away from the extrusion wheel 501, causing the distance between the hot-end assembly 502 and the bracket 503 to change. Therefore, the distance between the hot-end assembly 502 and the bracket 503 is correlated with the extrusion force exerted by the printing material on the hot-end assembly. After obtaining the distance between the hot-end assembly 502 and the bracket 503, the extrusion force exerted by the printing material on the hot-end assembly 502 can be obtained by converting the distance into extrusion force.

[0089] 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 a user from being burned when accidentally touching the hot end assembly.

[0090] In the embodiment of the present application, a distance sensing device is added between the bracket and the hot end assembly. The distance sensing device is used to sense the distance between the hot end assembly and the bracket, thereby obtaining the extrusion force exerted by the printing material on the hot end assembly (i.e., the extrusion force exerted on the hot end assembly). The structure is simple, the design is highly flexible, the space utilization rate is high, and the cost is low.

[0091] In some feasible implementations, the distance sensor device 504 includes a coil, and the plane where the coil is located is parallel to the surface of the heat dissipation fin 5021 .

[0092] For example, taking the first compensation coefficient as an example, the extrusion speed of the extrusion wheel is switched under the compensation of the first compensation coefficient, and the multiple extrusion forces exerted on the hot end assembly are measured as shown in Figure 6. Within the extrusion speed variation period T of the extrusion wheel, the extrusion force f exerted on the hot end assembly varies. The extrusion force f is represented by the solid line portion shown in Figure 6 as an example.

[0093] Optionally, the extrusion speed of the extrusion wheel is in the first period T1 (ie, 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 assembly increases from the first moment t 61 Increases until the second moment t 62 tends to be stable. Then we can set 61 and the second moment t 62 The extrusion force f received by the hot end component during the period is taken as the first 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 first period T1 at the second moment t 62 Afterwards, at the second moment t 62 To the third moment t 63 The extrusion force f received by the hot end assembly during the second time t is used as the first theoretical extrusion force F1 corresponding to the first compensation coefficient of the hot end assembly. For example, the extrusion force f received by the hot end assembly at the second time t 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 the preset range. For example, at the second moment t 62 The extrusion force obtained by sampling and the second moment t 62 The extrusion forces sampled at the previous sampling moment are equal in magnitude.

[0094] In this application, the extruder wheel continuously extrudes more printing material during the acceleration period, and the extrusion force on the hot end assembly continues to increase and then stabilizes. The value at which it stabilizes is the theoretical extrusion force of the extruder wheel. In this case, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and improving efficiency.

[0095] 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 used 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 ... 64 Afterwards, 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 previous sampling moment is within the preset range. For example, at the fourth moment t 64 The extrusion force obtained by sampling and the fourth moment t 64 The extrusion forces sampled at the previous sampling moment are equal in magnitude. FIG6 takes the example of the first theoretical extrusion force being greater than the first actual extrusion force, and the second actual extrusion force being 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.

[0096] 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.

[0097] In this application, the extruder wheel continuously reduces the amount of extruded printing material during the deceleration period, and the extrusion force on the hot end assembly continuously decreases and then stabilizes. The value at which it stabilizes is the theoretical extrusion force of the extruder wheel. In this case, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and improving efficiency.

[0098] Step 303 : Obtain a target compensation coefficient of the extrusion wheel according to a plurality of extrusion forces applied to the hot end component corresponding to the first compensation coefficient.

[0099] 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 cavity of the hot end assembly can be expressed as:

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

[0101] According to Formula 1, the pressure of the hot melt 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 assembly is proportional to the extrusion force exerted on the hot end assembly.

[0103] Therefore, the flow rate of the hot end assembly is proportional to the extrusion force applied to the hot end assembly. The flow rate curve of the hot end assembly can be shown in FIG7 , that is, the flow rate curve of the hot end assembly has the same trend as the curve of the extrusion force applied to the hot end assembly.

[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] Combining Figures 6 and 8, we can see that during the first cycle T1, the first theoretical extrusion force corresponding to the first compensation coefficient is greater than the first actual extrusion force experienced by the hot end assembly, meaning that during the first cycle, the hot end assembly is underextruded. At this point, the difference between the first theoretical extrusion force corresponding to the first compensation coefficient and the first actual extrusion force experienced by the hot end assembly is integrated over time during the first cycle to obtain the first flow area difference S1 corresponding to the first compensation coefficient, which can be expressed as:

[0106] During the second period T2, the second theoretical extrusion force corresponding to the first compensation coefficient is less than the second actual extrusion force experienced by the hot end assembly, meaning that during the second period, the hot end assembly is overextruded. At this point, the difference between the second actual extrusion force experienced by the hot end assembly and the second theoretical extrusion force corresponding to the first compensation coefficient is integrated over time during the second period to obtain the second flow area difference S2 corresponding to the first compensation coefficient, which can be expressed as:

[0107] 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.

[0108] The above text, in combination with Figures 6 to 8, describes a method for calculating the flow difference of the first compensation coefficient among multiple compensation coefficients. By changing the size of the compensation coefficient, the flow differences corresponding to multiple compensation coefficients can be obtained according to the method of calculating the flow difference of the first compensation coefficient in the above text.

[0109] 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.

[0110] Wherein, the target compensation coefficient of the extrusion wheel is obtained according to the flow difference of the hot end component under each compensation coefficient.

[0111] In some feasible embodiments, after steps 301 to 303, the flow difference corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient can be obtained. Based on 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 target compensation coefficient of the extruder wheel is obtained. The present application selects the target compensation coefficient based on the positive and negative relationship between the two values, which is simple and effective and can accurately obtain the target compensation coefficient of the extruder wheel.

[0112] Optionally, in some feasible embodiments, since the flow rate of the hot end component is proportional to the extrusion force applied to 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 applied to the hot end component.

[0113] 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.

[0114] 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 as:

[0115] 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 that the hot end component receives corresponding to the first compensation coefficient. If the hot end component receives multiple extrusion forces corresponding to the first compensation coefficient, F A1 It can be the average or median of multiple extrusion forces.

[0116] 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 pre-set 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 obtained as 1.6.

[0117] 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 as:

[0118] 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 that the hot end component receives corresponding to the first compensation coefficient. If the hot end component receives multiple extrusion forces corresponding to the first compensation coefficient, F A2 It 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 the pre-set extrusion force and positive correlation coefficient mapping table based on the extrusion force F A2 Can be found.

[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 pre-set 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 obtained as 1.44.

[0120] In some feasible implementations, the following describes how to determine a target compensation coefficient from multiple compensation coefficients in conjunction with the flowchart of the extrusion compensation method for the extrusion wheel shown in FIG9 . The specific steps are as follows:

[0121] Step 901: Set the current compensation coefficient C=C0.

[0122] Here, C0 can be understood as an initial compensation coefficient, which is a pre-set value. For example, the value of C0 can be 0; it can also be a value set based on experience to reduce the number of iterations.

[0123] 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. This step can be referred to as step 301 in the embodiment described above in conjunction with FIG3 , and will not be described in detail here.

[0124] Step 903: Obtain multiple extrusion forces. This step can refer to step 302 in the embodiment described above in conjunction with Figures 3 to 5, and will not be described in detail here.

[0125] Step 904: Calculate the flow difference of the hot end assembly. This step can refer to step 302 in the embodiment described above in conjunction with FIG. 3 and FIG. 6 , and will not be described in detail here.

[0126] 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.

[0127] For example, when step 901 is executed for the first time, the operation starts with the initial compensation coefficient. If 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, step 906b is executed. Then, step 907a or 907b is executed.

[0128] Step 906a: Use the current compensation coefficient C as the target compensation coefficient of the extrusion wheel.

[0129] If the flow rate difference of the hot-end component under the current compensation coefficient C is positive, and the flow rate difference under the previous compensation coefficient is negative, this indicates that the current compensation coefficient C (i.e., the second compensation coefficient) is too small, and the previous compensation coefficient (i.e., the first compensation coefficient) is too large. At this point, the second compensation coefficient is close to the desired value and can be used as the target compensation coefficient for the extruder, improving the printing quality of the 3D printer. Alternatively, the first compensation coefficient can also be used as the target compensation coefficient for the extruder.

[0130] Alternatively, if the flow rate difference of the hot-end assembly under the current compensation coefficient C is negative, and the flow rate difference of the hot-end assembly under the previous compensation coefficient is positive, this indicates that the current compensation coefficient C (i.e., the second compensation coefficient) is too large, and the previous compensation coefficient (i.e., the first compensation coefficient) is too small. In this case, the second compensation coefficient is close to the desired value and can be used as the target compensation coefficient for the extruder, improving the printing quality of the 3D printer. Alternatively, the first compensation coefficient can also be used as the target compensation coefficient for the extruder.

[0131] 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.

[0132] Step 907a, C=C+0.001. If the flow difference value of the hot end assembly under the current compensation coefficient C and the flow difference value under the previous compensation coefficient are both positive, this indicates that the current compensation coefficient C (i.e., the second compensation coefficient) and the previous compensation coefficient (i.e., the first compensation coefficient) are too small. Therefore, the second compensation coefficient is increased by a first preset step size. Steps 901 to 905 are repeated until the flow difference value of the hot end assembly under the second compensation coefficient has a different sign from the flow difference value under the first compensation coefficient. The second compensation coefficient is then used as the target compensation coefficient for the extruder.

[0133] FIG9 takes the first preset step size of 0.001 as an example. The first preset step size may also be set to other values. This application does not limit the value of the first preset step size.

[0134] Step 907b, C = C - 0.001. If the flow difference value of the hot end assembly under the current compensation coefficient C and the flow difference value under the previous compensation coefficient are both negative, this indicates that the current compensation coefficient C (i.e., the second compensation coefficient) and the previous compensation coefficient (i.e., the first compensation coefficient) are too large. In this case, the second compensation coefficient is reduced according to a second preset step size. Steps 901 to 905 are then repeated until the flow difference value of the hot end assembly under the second compensation coefficient has a different sign from the flow difference value under the first compensation coefficient. The second compensation coefficient is then used as the target compensation coefficient for the extruder.

[0135] FIG9 takes the second preset step size of 0.001 as an example. The second preset step size may be equal to the first preset step size or may be set to other values. This application does not limit the value of the second preset step size.

[0136] In this application, the flow difference of the hot end component is changed by dynamically changing the compensation coefficient, and the hot end component can be dynamically compensated for the flow during the 3D printing process. The operation is simple and efficient.

[0137] In some feasible embodiments, the present application also provides a 3D printer, which is provided with a print head and a controller, and the print head body is provided with an extrusion wheel and a hot end assembly. The controller can execute the embodiments described above in combination with Figures 3 to 9, thereby realizing dynamic flow compensation of the 3D printer and improving the printing effect of the 3D printer.

[0138] An embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the embodiments described above in conjunction with Figures 3 to 9 are implemented.

[0139] An embodiment of the present application further provides a computer program product, including a computer program, wherein the computer program implements the embodiments described above in conjunction with Figures 3 to 9 when executed by a processor.

[0140] It should be noted that the above terms "first" and "second" are used for descriptive purposes only 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 is a negative number, 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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