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

Abstract

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

Description

[0001] This application claims priority to Chinese Patent Application No. 202311099096.7, filed on August 28, 2023, entitled "An Extrusion Compensation Method for an Extrusion Roller, a 3D Printer and an Electronic Device", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This 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 electronic equipment. Background Technology

[0003] In the process of fused deposition modeling (FMD) 3D printing, the extrusion rollers in the 3D printer extrude printing material to the hot end assembly, which heats the printing material to a molten state and then flows out.

[0004] Because the extrusion feeding process of the extrusion roller is not entirely rigid, the hot-end assembly cannot achieve the desired flow rate change when the extrusion speed of the extrusion roller changes. For example, as... Figure 1 As shown, when the extrusion speed of the extrusion roller 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 printhead movement, resulting in bulging; when the extrusion speed of the extrusion roller increases, the flow rate of the hot end component is too slow, causing a lack of material in the high-speed area of ​​the printhead movement, resulting in gaps.

[0005] To address the aforementioned issues, the extrusion feed rate of one extrusion wheel can be increased or decreased based on the desired flow rate. This involves setting a compensation coefficient for the extrusion wheel to rapidly alter the pressure within the hot-melt cavity of the hot-end assembly, thereby quickly changing the flow rate of the hot-end assembly. Therefore, determining the compensation coefficient for the extrusion wheel is a crucial issue requiring further research. Summary of the Invention

[0006] This 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, and is highly automated and fast.

[0007] In a first aspect, embodiments of this application provide an extrusion compensation method for an extrusion wheel, the extrusion compensation method being applicable to a 3D printer, the 3D printer including an extrusion wheel and a hot-end assembly, the extrusion compensation method comprising:

[0008] The extrusion wheel is controlled to switch from a first extrusion speed to a second extrusion speed under the compensation of a first compensation coefficient, extruding printing material to the hot end assembly;

[0009] Obtain the multiple extrusion forces acting on the hot-end component corresponding to the first compensation coefficient.

[0010] The target compensation coefficient of the extrusion wheel is obtained based on the multiple extrusion forces acting on the hot end component corresponding to the first compensation coefficient.

[0011] This application can automatically calibrate the compensation coefficient of the extrusion wheel, thereby automatically compensating for the extrusion feed amount of the extrusion wheel without user intervention. It is highly automated, fast, efficient and low cost.

[0012] In conjunction with the first aspect, in a first possible implementation, obtaining the multiple extrusion forces acting on the hot-end assembly includes:

[0013] The hot end assembly is subjected to multiple extrusion forces after the extrusion wheel switches the extrusion speed.

[0014] In a second possible implementation, in conjunction with the first aspect or any of the possible implementations described above, obtaining the target compensation coefficient of the extrusion wheel based on the multiple extrusion forces acting on the hot-end assembly corresponding to the first compensation coefficient includes:

[0015] The extrusion wheel is controlled to switch from a third extrusion speed to a fourth extrusion speed under the compensation of a second compensation coefficient, and the extrusion material is extruded onto the hot end assembly; wherein the third extrusion speed can be the first extrusion speed and the fourth extrusion speed can be the second extrusion speed.

[0016] Obtain the multiple extrusion forces experienced by the hot-end component corresponding to the second compensation coefficient;

[0017] The target compensation coefficient of the extrusion wheel is obtained based on the multiple extrusion forces received by the hot end assembly corresponding to the first compensation coefficient and the multiple extrusion forces received by the hot end assembly corresponding to the second compensation coefficient.

[0018] This application iterates the compensation coefficient and determines the target compensation coefficient of the extrusion wheel based on the multiple extrusion forces corresponding to different compensation coefficients of the hot end component, thereby improving the accuracy of the target compensation coefficient.

[0019] In a third possible implementation, in combination with the first aspect or any of the above possible implementations of the first aspect, 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 based on the multiple extrusion forces received by the hot-end assembly corresponding to the first compensation coefficient and the multiple extrusion forces received by the hot-end assembly corresponding to the second compensation coefficient includes:

[0021] The difference between the theoretical extrusion force and the actual extrusion force corresponding to the same compensation coefficient of the hot end component is integrated over time within the extrusion speed variation cycle of the extrusion wheel to obtain the flow rate difference of the hot end component corresponding to the first compensation coefficient and the flow rate difference of the hot end component corresponding to the second compensation coefficient.

[0022] The target compensation coefficient of the extrusion wheel is obtained based on the positive or 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 this application, considering the differences in materials, the varying heating temperatures of the printing material by the hot-end assembly, and the different pore sizes of the molten printing material flowing out of the hot-end assembly, there is a difference between the actual extrusion force exerted by the printing material on the hot-end assembly and the theoretical extrusion force when the extrusion speed of the extrusion wheel changes. Therefore, the target compensation coefficient of the extrusion wheel can be calibrated based on the difference between the actual and theoretical extrusion forces exerted by the printing material on the hot-end assembly, with high accuracy.

[0024] In a fourth possible implementation, combining the first aspect or any of the above possible implementations, the step of obtaining the target compensation coefficient of the extrusion wheel based on the positive or negative relationship between the flow difference of the hot-end assembly corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient includes:

[0025] When the flow difference between the hot-end component and the first compensation coefficient is positive, and the flow difference between the hot-end component and the second compensation coefficient is negative, the second compensation coefficient is used as the target compensation coefficient for the extrusion wheel. 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 expected value and can be used as the target compensation coefficient for the extrusion wheel, thus improving the printing effect of the 3D printer.

[0026] In a fifth possible implementation, combining the first aspect or any of the possible implementations described above, the step of obtaining the target compensation coefficient of the extrusion wheel based on the positive or negative relationship between the flow difference of the hot-end assembly corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient includes:

[0027] When the flow difference between the hot-end component and the first compensation coefficient is negative, and the flow difference between the hot-end component and the second compensation coefficient is positive, the second compensation coefficient is used as the target compensation coefficient for the extrusion wheel. 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 expected value and can be used as the target compensation coefficient for the extrusion wheel, thus improving the printing effect of the 3D printer.

[0028] In a fifth possible implementation, combining the first aspect or any of the possible implementations described above, the step of obtaining the target compensation coefficient of the extrusion wheel based on the positive or negative relationship between the flow difference of the hot-end assembly corresponding to the first compensation coefficient and the flow difference corresponding to the second compensation coefficient includes:

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

[0030] In this 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 a seventh possible implementation, combining the first aspect or any of the possible implementations described above, the step of obtaining the target compensation coefficient of the extrusion wheel based on the positive or negative relationship between the flow difference of the hot-end assembly 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 by 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.

[0033] In this 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 a seventh possible implementation, in combination with the first aspect or any of the above possible implementations of the first aspect, the extrusion speed variation cycle of the extrusion wheel includes a first cycle and a second cycle; the theoretical extrusion force corresponding to each compensation coefficient includes a first theoretical extrusion force and a second theoretical extrusion force; and 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 corresponding to the same compensation coefficient of the hot-end component is integrated over time within the extrusion speed variation cycle of the extrusion wheel to obtain the flow rate difference of the hot-end component corresponding to the first compensation coefficient and the flow rate difference of the hot-end component corresponding to the second compensation coefficient, including:

[0036] The difference between the first theoretical extrusion force and the first actual extrusion force corresponding to each compensation coefficient is integrated over time within the first cycle to obtain the first flow area difference corresponding to each compensation coefficient.

[0037] The difference between the second actual extrusion force and the second theoretical extrusion force corresponding to each compensation coefficient is integrated over time in the second period to obtain the 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 and deceleration of the extrusion wheel, thus comprehensively considering both acceleration and deceleration processes, further improving accuracy. Furthermore, the target compensation coefficient obtained in this application is applicable to different application scenarios of the extrusion wheel. Especially during right-angle 3D printing, where the extrusion wheel decelerates horizontally and accelerates vertically, the total speed of the extrusion wheel exhibits a process of acceleration, deceleration, and then acceleration again. During this process, a single target compensation coefficient can be used to compensate for the extrusion feed amount without frequently changing the value of the compensation coefficient, resulting in high reliability.

[0040] In the ninth possible implementation, in combination with the first aspect or any of the above possible implementations of the first aspect, the extrusion force corresponding to the first compensation coefficient increases from the first moment to the second moment within the first period.

[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 time and the second time.

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

[0043] In this application, the extrusion wheel continuously increases the amount of printing material extruded during the acceleration period, and the extrusion force on the hot end component continuously increases before stabilizing. The stable value is the theoretical extrusion force of the extrusion wheel. At this point, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and achieving high efficiency.

[0044] In the tenth possible implementation, in combination with the first aspect or any of the above possible implementations of the first aspect, during the second period, the extrusion force corresponding to the first compensation coefficient decreases from the third moment until it stabilizes 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 time and the fourth time.

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

[0047] In this application, the extrusion wheel continuously reduces the amount of printing material being extruded during the deceleration period. The extrusion force on the hot-end component gradually decreases and then stabilizes. The stable value is the theoretical extrusion force of the extrusion wheel. At this point, using the sampled value as the theoretical value avoids tedious theoretical calculations, saves system computing resources, and is highly efficient.

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

[0049] The process of extruding printing material into the hot-end assembly at different extrusion speeds includes:

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

[0051] This application only requires controlling the motor speed to control the extrusion speed of the extrusion wheel, resulting in a high degree of automation.

[0052] In a twelfth possible implementation, in conjunction with the first aspect or any of the above possible implementations of the first aspect, the 3D printer has a support between the extrusion wheel and the hot end assembly, wherein the support has a distance sensing device on the side facing the hot end assembly.

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

[0054] In this application, the cost of measuring the extrusion force on the hot end component can be reduced, and the structure is simple and compact.

[0055] Secondly, embodiments of this application provide a 3D printer, which includes a print head and a controller. The print head body is provided with an extrusion wheel and a hot end assembly. The controller is used to execute the extrusion compensation method described in conjunction with the first aspect or any of the possible implementations of the first aspect.

[0056] Thirdly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the extrusion compensation method described in conjunction with the first aspect or any of the possible implementations of the first aspect.

[0057] Fourthly, embodiments of this application provide a computer program product, including a computer program, wherein the computer program, when executed by a processor, implements the extrusion compensation method described in conjunction with the first aspect or any of the possible implementations of the first aspect.

[0058] It should be understood that the implementations and beneficial effects of the above-mentioned aspects of this application can be referenced from each other. Attached Figure Description

[0059] Figure 1 This is a schematic diagram of an object printed by an existing 3D printer when the printing speed varies.

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

[0061] Figure 3 A schematic flowchart of an extrusion compensation method for an extrusion wheel provided in an embodiment of this application;

[0062] Figure 4 A schematic diagram of the structure of a printhead provided in an embodiment of this application;

[0063] Figure 5 Another schematic diagram of the printhead provided in the embodiments of this application;

[0064] Figure 6 A schematic diagram of the extrusion force curve of the hot-end component provided in the embodiments of this application;

[0065] Figure 7 A schematic diagram of the flow rate curve of the hot-end component provided in an embodiment of this application;

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

[0067] Figure 9 This is another schematic flowchart of an extrusion compensation method for an extrusion wheel provided in an embodiment of this application. Detailed Implementation

[0068] The implementation of the technical solution of this application will be further described in detail below with reference to the accompanying drawings.

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

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

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

[0072] For example, the 3D printer 102 also includes a printing platform 1022, on which the hot end assembly 10212 can extrude molten printing material onto the printing platform 1022.

[0073] In specific implementation, the print head 1021 is slidably connected to the first guide rail 1023, allowing the print head 1021 to move along the length of the first guide rail 1023, thus achieving displacement of the print head 1021 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 the printing platform 1022 to move along the length of the second guide rail 1024, thus achieving displacement of the print head 1021 relative to the printing platform 1022 along the length of the second guide rail 1024, the length of which is perpendicular to the length of the first guide rail 1023. Furthermore, the first guide rail 1023 is connected to a third guide rail 1025. By moving the first guide rail 1023 along the third guide rail 1025, the 3D printer 102 can achieve displacement of the print head 1021 relative to the printing platform 1022 in directions perpendicular to the length of the second guide rail 1024 and also perpendicular to the length of the first guide rail 1023. That is, the 3D printer 102 can achieve three mutually perpendicular printing paths to print three-dimensional objects.

[0074] In this application, the compensation coefficient of the extrusion wheel is automatically calibrated, thereby automatically compensating for the extrusion feed amount of the extrusion wheel, that is, compensating for the printing material supplied by the extrusion wheel to the hot end component. No user intervention is required, and the automation level is high, the speed is fast, the efficiency is high and the cost is low.

[0075] The following is combined Figures 3 to 9 The extrusion compensation method for the extrusion wheel provided in this application is described in detail.

[0076] See Figure 3, Figure 3 This is a schematic flowchart illustrating an extrusion compensation method for an extrusion wheel, provided as an embodiment of this application. Figure 3 As shown, the extrusion compensation method for the extrusion wheel includes the following steps:

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

[0078] The various steps of the extrusion compensation method provided in this application can be executed by one or more controllers with communication connections. The controller can be located at the print head of the 3D printer, at a base connected to a second guide rail, or at a base connected to a third guide rail. That is, this application does not limit the number of controllers or their location.

[0079] For example, the controller may be a micro control unit (MCU), a central processing unit (CPU), other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0080] The extrusion wheel is connected to a motor, which can rotate at different speeds according to different control signals sent by the controller, allowing the extrusion wheel to extrude printing material into the hot-end assembly at different extrusion speeds. For example, the extrusion wheel is connected to the motor shaft, meaning the motor's rotational speed is correlated with the extrusion wheel's speed; switching the extrusion speed of the extrusion wheel can be achieved simply by controlling the motor's rotational speed.

[0081] Step 302: Obtain multiple extrusion forces acting on the hot-end component corresponding to the first compensation coefficient. Optionally, information on the extrusion force acting on the hot-end component corresponding to the first compensation coefficient can be obtained from a measuring component. This information includes the theoretical extrusion force and the actual extrusion force corresponding to the first compensation coefficient. For example, the theoretical extrusion force can be a pre-set 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 sensing device.

[0082] Different extrusion speeds of the extrusion roller result in different pressures in the hot-melt cavity of the hot-end assembly, leading to different extrusion forces on the hot-end assembly. In specific implementation, the moment when the hot-end assembly experiences multiple extrusion forces corresponding to the first compensation coefficient is the moment when the extrusion roller switches extrusion speeds.

[0083] In some feasible implementations, this application can employ the cantilever surface strain method to measure the extrusion force on the hot-end assembly. See also Figure 4 , Figure 4 This is a schematic diagram of the structure of a printhead provided in an embodiment of this 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 presses the printing material 42 onto 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 on the surface of the strain cantilever 45. 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 related to 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 feasible implementations, see [link to relevant documentation]. Figure 5 , Figure 5 This is yet another schematic diagram of the printhead provided in an embodiment of this application. For example... Figure 5 As shown, the printhead body 500 is provided with an extrusion wheel 501, a hot end assembly 502, and a support 503 located between the extrusion wheel 501 and the hot end assembly 502.

[0085] The bracket 503 has a distance sensing device 504 on the side facing the hot end assembly 502. The distance sensing device 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] For example, the hot end assembly 502 includes heat dissipation fins 5021, a nozzle 5023, and a heating unit. The heating unit can be used to heat the printing material, which is then molten and extruded through the nozzle 5023.

[0087] The stiffness of the printhead body 500 is within a certain range. Stiffness refers to the ability of a material or structure to resist elastic deformation under stress; that is, the printhead body 500 is not completely rigid. When the extrusion roller 501 pushes the printing material towards the hot-end assembly 502, the nozzle 5023 in the hot-end assembly 502 is subjected to extrusion force, causing the heat sink fins 5021 to move away from the extrusion roller 501, thus changing the distance between the hot-end assembly 502 and the support 503. Therefore, the distance between the hot-end assembly 502 and the support 503 is related to 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 support 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.

[0088] Optionally, the hot end assembly 502 may also 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] This application embodiment adds a distance sensing device between the support and the hot end component. The distance sensing device is used to sense the distance between the hot end component and the support, thereby obtaining the extrusion force exerted by the printing material on the hot end component (i.e. the extrusion force on the hot end component). The structure is simple, the design is flexible, the space utilization is high, and the cost is low.

[0090] In some feasible implementations, the distance sensing device 504 includes a coil, the plane of which is parallel to the surface of the heat sink 5021.

[0091] For example, taking multiple compensation coefficients, including a first compensation coefficient, under the compensation of this first compensation coefficient, by switching the extrusion speed of the extrusion wheel, the multiple extrusion forces on the hot-end assembly can be measured as follows: Figure 6 As shown. Within the extrusion speed variation period T of the extrusion roller, the extrusion force f on the hot end assembly varies, and is expressed as the extrusion force f. Figure 6 Take the solid line portion shown as an example.

[0092] Optionally, the extrusion speed of the extrusion wheel is set in the first cycle T1 (i.e., the first moment t). 61 By the third moment t 63 The extrusion force f on the hot-end assembly increases during the first cycle T1. 61 Increase until the second time t 62 It tends to stabilize. Therefore, at the first moment t... 61 With the second time t 62 The extrusion force f experienced by the hot-end component is taken as the first actual extrusion force experienced by the hot-end component corresponding to the first compensation coefficient, and the second time t within the first period T1 is considered. 62Then, at the second time t 62 By the third moment t 63 The extrusion force f experienced by the hot-end component is taken as the first theoretical extrusion force F1 corresponding to the first compensation coefficient of the hot-end component. For example, the extrusion force f experienced by the hot-end component at the second time t... 62 The trend towards stability can be understood as the second time step t. 62 The extrusion force obtained from the sampling and the second time t 62 The magnitudes of the extrusion forces sampled at the previous sampling time are within a preset range. For example, at the second sampling time t... 62 The extrusion force obtained from the sampling and the second time t 62 The extrusion forces obtained from the previous sampling time are equal in magnitude.

[0093] In this application, the extrusion wheel continuously increases the amount of printing material extruded during the acceleration period, and the extrusion force on the hot end component continuously increases before stabilizing. The stable value is the theoretical extrusion force of the extrusion wheel. At this point, the sampled value is used as the theoretical value, avoiding tedious theoretical calculations, saving system computing resources, and achieving high efficiency.

[0094] Similarly, the extrusion speed of the extrusion wheel is in the second period T2 (i.e., the third time t). 63 up to the fifth moment t 65 The extrusion force f on the hot-end assembly decreases during the second period T2. 63 Decrease until the fourth time t 64 It tends to stabilize. Then, the third time t can be... 63 By the fourth moment t 64 The extrusion force f experienced by the hot-end component is taken as the second actual extrusion force experienced by the hot-end component corresponding to the first compensation coefficient, and the second period T2 is within the fourth time t. 64 Then, at the fourth time t 64 up to the fifth moment t 65 The extrusion force f experienced by the hot-end component is used as the second theoretical extrusion force F2 corresponding to the first compensation coefficient of the hot-end component. For example, the extrusion force f experienced by the hot-end component at the fourth time t... 64 The trend towards stability can be understood as the fourth time step t. 64 The extrusion force obtained from the sampling and the fourth time t 64 The magnitudes of the extrusion forces sampled at the previous sampling time are within a preset range. For example, at the fourth time t... 64 The extrusion force obtained from the sampling and the fourth time t 64 The extrusion forces obtained from the previous sampling time are equal in magnitude. Figure 6Taking the first theoretical extrusion force as greater than the first actual extrusion force and the second actual extrusion force as greater than the second theoretical extrusion force as an example, optionally, the first theoretical extrusion force can be less than the first actual extrusion force, or the second actual extrusion force can be less than the second theoretical extrusion force.

[0095] Alternatively, the second theoretical extrusion force can be determined based on the first theoretical extrusion force, for example, the first theoretical extrusion force and the second theoretical extrusion force can be proportional.

[0096] In this application, the extrusion wheel continuously reduces the amount of printing material being extruded during the deceleration period. The extrusion force on the hot-end component gradually decreases and then stabilizes. The stable value is the theoretical extrusion force of the extrusion wheel. At this point, using the sampled value as the theoretical value avoids tedious theoretical calculations, saves system computing resources, and is highly efficient.

[0097] Step 303: Based on the multiple extrusion forces received by the hot end component corresponding to the first compensation coefficient, the target compensation coefficient of the extrusion wheel is obtained.

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

[0099]

[0100] Among them, Q R 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 of the hot-melt cavity of the hot-end assembly, H is a 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 in the hot-melt cavity of the hot-end component is directly 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 on the hot end component.

[0103] Therefore, the flow rate of the hot-end component is directly proportional to the extrusion force acting on it. The flow rate curve of the hot-end component can then be expressed as follows: Figure 7 As shown, the flow rate curve of the hot end component follows the same trend as the extrusion force curve of 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 cycle of the extrusion wheel to obtain the flow rate difference under each compensation coefficient.

[0105] Combination Figure 6 and Figure 8It can be seen that within 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, meaning that the hot-end component is under-extruded within the first cycle. 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 within 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] During the second cycle 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 component, meaning that the extrusion of the hot-end component is excessive during the second cycle. At this time, the difference between the second actual extrusion force experienced by the hot-end component and the second theoretical extrusion force corresponding to the first compensation coefficient is integrated over time during the second cycle 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 point, 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 preceding text Figures 6 to 8 This describes the calculation method for the flow difference of the first compensation coefficient among multiple compensation coefficients. By changing the size of the compensation coefficients, the flow difference corresponding to multiple compensation coefficients can be obtained in the same way as the flow difference of the first compensation coefficient was calculated earlier.

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

[0112] The target compensation coefficient of the extrusion wheel is obtained based on the flow difference of the hot end assembly under 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 corresponding to the second compensation coefficient can be obtained. Based on the positive and negative relationship between the flow difference of the hot end assembly under the first compensation coefficient and the flow difference under the second compensation coefficient, the target compensation coefficient of the extrusion wheel is obtained. This application selects the target compensation coefficient based on the positive and negative relationship between two values, which is simple and effective, and can accurately obtain the target compensation coefficient of the extrusion wheel.

[0114] Optionally, in some feasible implementations, 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 based on the extrusion force, according to the proportional relationship between the flow rate of the hot end component and the extrusion force applied to the hot end component.

[0115] In some feasible implementations, the target compensation coefficient of the extrusion wheel can be obtained based on the theoretical extrusion force and the actual extrusion force corresponding to the hot end component 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 have a linear multiple relationship. For example, the target compensation coefficient k can be expressed by the formula:

[0117]

[0118] Where k1 is the first compensation coefficient, F T1 F is the theoretical extrusion force corresponding to the first compensation coefficient. A1 This is the actual extrusion force experienced by the hot-end component corresponding to the first compensation coefficient. If there are multiple extrusion forces experienced by 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 the first compensation coefficient k1 = 0.8, the theoretical extrusion force of the hot end component is 10N. This theoretical extrusion force can be a pre-set target value. However, 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.

[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, as well as the positive correlation between extrusion force and 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] Where k1 is the first compensation coefficient, F T2 F is the theoretical extrusion force corresponding to the first compensation coefficient. A2 This is the actual extrusion force experienced by the hot-end component corresponding to the first compensation coefficient. If there are multiple extrusion forces experienced by the hot-end component corresponding to the first compensation coefficient, F A2This 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 derived from a pre-set extrusion force and positive correlation coefficient mapping table, based on the extrusion force F. A2 It can be found.

[0123] Assuming the first compensation coefficient k1 = 0.8, the theoretical extrusion force of the hot end component is 10N. This theoretical extrusion force can be a pre-set target value. However, 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.

[0124] In some feasible implementation methods, the following are combined with Figure 9 The flowchart illustrating the extrusion compensation method for the extrusion wheel explains 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] Here, C0 can be understood as the initial compensation coefficient, which is a pre-set 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 extrusion roller to switch from the first extrusion speed to the second extrusion speed to extrude the printing material onto the hot-end assembly. This step can be referred to in conjunction with the previous text. Figure 3 Step 301 in the described embodiment will not be repeated here.

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

[0129] Step 904: Calculate the flow difference of the hot-end components. This step can be referred to in conjunction with the previous text. Figure 3 and Figure 6 Step 302 in the described embodiment will not be repeated 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 both negative. If yes, proceed to step 906b; otherwise, proceed to step 906a.

[0131] For example, when step 901 is executed for the first time, the process starts with an initial compensation coefficient. The previous compensation coefficient of this initial compensation coefficient either does not exist or is the initial compensation coefficient itself. In this case, step 906b is executed. Then, step 907a or 907b is executed.

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

[0133] The flow difference of the hot-end component under the current compensation coefficient C is a positive number, while the flow difference under the previous compensation coefficient is a negative number. 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 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 for the extrusion wheel.

[0134] Alternatively, if the flow difference of the hot-end component under the current compensation coefficient C is negative, and the flow difference of the hot-end component under the previous compensation coefficient is positive, it 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 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 for the extrusion wheel.

[0135] Step 906b: Determine whether the flow difference of the hot-end component under the current compensation coefficient C and the flow difference under the previous compensation coefficient are both positive. If yes, proceed to step 907a; otherwise, proceed to step 907b.

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

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

[0138] Step 907b, C = C - 0.001. The flow difference of the hot-end component under the current compensation coefficient C and the flow difference under the previous compensation coefficient are both negative, indicating 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. Therefore, the second compensation coefficient is reduced by the second preset step size. Then, steps 901 to 905 are repeated until the sign of the flow difference of the hot-end component under the second compensation coefficient is different from that under the first compensation coefficient. The second compensation coefficient is then used as the target compensation coefficient for the extrusion wheel.

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

[0140] In this application, the flow difference of the hot end component is changed by dynamically changing the compensation coefficient. This allows for dynamic flow compensation of the hot end component during the 3D printing process, which is simple to operate and highly efficient.

[0141] In some feasible embodiments, this application also provides a 3D printer, which 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 perform the functions described above. Figures 3 to 9 The described embodiments enable dynamic flow compensation for 3D printers, thereby improving the printing results of 3D printers.

[0142] One embodiment of this application also provides a computer-readable storage medium on which a computer program is stored. When the computer program is executed by a processor, it implements the foregoing description. Figures 3 to 9 The described embodiments.

[0143] An embodiment of this application also provides a computer program product, including a computer program, wherein the computer program, when executed by a processor, implements the foregoing description. Figures 3 to 9 The described embodiments.

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

Claims

1. A method for extrusion compensation of an extrusion wheel, characterized in that, The extrusion compensation method is applicable to a 3D printer, which includes an extrusion roller and a hot end assembly. The 3D printer is equipped with a measuring component for measuring the extrusion force acting on the hot end assembly. The extrusion compensation method includes: The extrusion wheel is controlled to switch from a first extrusion speed to a second extrusion speed under the compensation of a first compensation coefficient, extruding printing material onto the hot end assembly; Information on the extrusion force received by the hot end component corresponding to the first compensation coefficient is obtained from the measuring component; Based on the information of the extrusion force received by the hot end component corresponding to the first compensation coefficient, the target compensation coefficient of the extrusion wheel is obtained; the target compensation coefficient of the extrusion wheel is obtained by processing the first compensation coefficient based on the proportional relationship between the theoretical extrusion force and the actual extrusion force; or, the target compensation coefficient of the extrusion wheel is 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.

2. The extrusion compensation method according to claim 1, characterized in that, The measurement components include strain gauges or distance sensing devices.

3. The extrusion compensation method according to claim 1 or 2, characterized in that, The 3D printer has a support between the extrusion wheel and the hot end assembly, and the measuring assembly includes a distance sensing device disposed on the side of the support facing the hot end assembly. The distance sensing device is used to sense the distance between the hot end assembly and the bracket.

4. The extrusion compensation method according to claim 1 or 2, characterized in that, The hot end assembly is connected to the strain cantilever, and the measuring assembly includes strain gauges attached to the surface of the strain cantilever. The strain gauge is used to measure the deformation of the strain cantilever surface.

5. A 3D printer, characterized in that, The 3D printer includes a printhead and a controller. The printhead body is provided with an extrusion wheel and a hot end assembly. The controller is used to perform the extrusion compensation method as described in any one of claims 1 to 4.

6. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, which, when executed by a processor, implements the extrusion compensation method for the extrusion wheel as described in any one of claims 1 to 4.

7. A computer program product, characterized in that, Includes a computer program, wherein the computer program, when executed by a processor, implements the extrusion compensation method for the extrusion wheel as described in any one of claims 1 to 4.

Images