A 3D printing system and printing control method

Abstract

The present invention relates to the field of 3D printing control technology, and in particular to a 3D printing system and a printing control method. According to the characteristic that the contour has a high demand for accuracy, boundary sub-paths and internal sub-paths are divided according to the proximity of the printing path relative to the slice, and the corresponding theoretical printing speed is determined. Then, the starting point printing speed and the end point printing speed of each printing sub-path are determined in combination with the characteristic that the direction change between the printing sub-paths will affect the printing effect, and further path planning is performed in combination with the path length of each printing sub-path, so that the planned printing speed of each path point is adaptively determined while taking into account the printing accuracy and printing efficiency, solving the problem that the accuracy and efficiency of each position cannot be taken into account when printing at a fixed printing speed, so that the accuracy and efficiency of 3D printing performed according to the planned printing speeds of all path points on all printing sub-paths are higher.

Description

Technical Field

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

[0002] 3D printing, also known as additive manufacturing, is a manufacturing technology that builds three-dimensional objects by adding materials layer by layer. Since stereolithography (SLA) can print smooth surface parts with fine features and can use different photosensitive resin materials to meet different application requirements, SLA 3D printing technology can be applied to specific fields such as medical device printing, automotive parts printing, and high-strength lightweight parts printing for aviation. With the continuous emergence of new materials and new technologies, its application scope and depth will continue to expand. Therefore, it is particularly important to control the SLA 3D printing system more accurately and improve printing accuracy and efficiency.

[0003] In existing 3D printing technology, the 3D model is usually sliced ​​and layered, and then printed at a fixed printing speed according to the obtained printing path; however, in the actual printing process, different positions have different details of the 3D model, resulting in different requirements for printing speeds at different positions; when printing at a fixed printing speed, it is impossible to take into account the accuracy and efficiency of each position, resulting in poor printing effects when 3D printing is performed at a fixed printing speed. Summary of the invention

[0004] The present application provides a 3D printing system and a printing control method. First, according to the characteristic of high accuracy requirements for contours, boundary sub-paths and internal sub-paths are divided according to the proximity of the printing path to the slice and the corresponding theoretical printing speed is determined. Then, the starting printing speed and the end printing speed of each printing sub-path are determined in combination with the characteristic that the direction change between the printing sub-paths will affect the printing effect. Further path planning is performed in combination with the path length of each printing sub-path, so as to adaptively determine the planned printing speed of each path point while taking into account printing accuracy and printing efficiency, solving the problem that the accuracy and efficiency of each position cannot be taken into account when printing at a fixed printing speed, so that the accuracy and efficiency of 3D printing performed according to the planned printing speed of all path points on all printing sub-paths are higher.

[0005] The present application provides a 3D printing control method, the method comprising:

[0006] Obtain all initial printing paths for each slice according to the three-dimensional model of the printed object;

[0007] Divide each initial printing path into at least one printing subpath according to the proximity of each initial printing path to a slice boundary; determine a theoretical printing speed of each printing subpath according to a maximum printing speed of the printer and a path type of each printing subpath; the path type includes a boundary subpath and an internal subpath;

[0008] Determine the starting point printing speed and the ending point printing speed of each printing subpath according to the path direction angle between adjacent printing subpaths and the theoretical printing speed of each printing subpath;

[0009] Determining the planned printing speed of each path point on each printing subpath according to the path length of each printing subpath, the starting point printing speed and the end point printing speed;

[0010] 3D printing is controlled according to the planned printing speed of all path points on all printing sub-paths.

[0011] Furthermore, the process of obtaining all initial printing paths of each slice layer according to the three-dimensional model of the printed object includes:

[0012] The three-dimensional model of the printed object is set to STL format and then imported into the slicing software CURA. The three-dimensional model of the printed object is sliced ​​into layers by the slicing software CURA to obtain all initial printing paths under each layer of slicing.

[0013] Furthermore, the process of obtaining the printing subpath includes:

[0014] The minimum distance between each path point on each initial printing path and the boundary of the corresponding layer slice is taken as the boundary distance of each path point;

[0015] Among all the path points on each initial printing path, the path points whose boundary distance is less than the preset distance threshold are regarded as boundary path points; the path points whose boundary distance is greater than the preset distance threshold are regarded as internal path points; and the path points whose boundary distance is equal to the preset distance threshold are regarded as suspected segmentation path points;

[0016] In the path direction on each initial printing path, the suspected segmentation path points whose path point types of the corresponding previous path points and the corresponding next path points are different are taken as the real segmentation path points;

[0017] Each initial printing path is divided into at least one printing sub-path using the actual segmentation path points as interval points.

[0018] Furthermore, the process of obtaining the theoretical printing speed includes:

[0019] The printing subpath without internal path points is regarded as the boundary subpath; the other printing subpaths outside the boundary subpath are regarded as internal subpaths;

[0020] The maximum printing speed of the printer is used as the theoretical printing speed of the internal sub-path; and half of the maximum printing speed of the printer is used as the theoretical printing speed of the boundary sub-path.

[0021] Furthermore, the process of determining the starting point printing speed and the ending point printing speed of each printing subpath according to the path direction angle between adjacent printing subpaths and the theoretical printing speed of each printing subpath includes:

[0022] Each printing sub-path is used as a target sub-path in turn; the next printing sub-path adjacent to the target sub-path in the printing sequence is used as a reference sub-path;

[0023] The included angle between the path direction corresponding to the target subpath and the path direction corresponding to the reference subpath is used as the extension change angle of the target subpath;

[0024] When the extension change angle is greater than a preset direction amplitude threshold, setting the preset printing speed as the end point printing speed of the target sub-path;

[0025] When the extension change angle is less than or equal to a preset direction amplitude threshold, the product of the negative correlation mapping value of the extension change angle and the theoretical printing speed of the target sub-path is used as the terminal point printing speed of the target sub-path;

[0026] The printing speed at the end point of the target sub-path is used as the printing speed at the start point of the reference sub-path.

[0027] Furthermore, the process of acquiring the planned printing speed includes:

[0028] Under the condition of constant acceleration, the theoretical printing time of each printing sub-path is determined according to the path length, the starting point printing speed and the end point printing speed of each printing sub-path; the priori reaction time and the priori maximum printing acceleration of the printer are obtained;

[0029] Under each printing sub-path, when half of the theoretical printing time is less than or equal to the prior reaction time, the planned printing speed of each path point under constant acceleration is obtained; when half of the theoretical printing time is greater than the prior reaction time, the planned printing speed of each path point under the uniform speed path is obtained.

[0030] Furthermore, when half of the theoretical printing time is greater than the priori reaction time, the process of obtaining the planned printing speed of each path point under the uniform speed path includes:

[0031] When half of the theoretical printing time is greater than the a priori reaction time, a first speed change path of each printing subpath is determined according to the starting printing speed of each printing subpath under a constant a priori maximum printing acceleration and the theoretical printing speed after acceleration; a second speed change path of each printing subpath is determined according to the theoretical printing speed of each printing subpath under a constant a priori maximum printing acceleration and the end printing speed after deceleration; a shortest theoretical path length of each printing subpath is determined according to the sum of the length of the first speed change path and the length of the second speed change path of each printing subpath; wherein the first speed change path and the second speed change path both include the instantaneous printing speed at each path point;

[0032] When the path length of the printing sub-path is greater than or equal to the corresponding shortest theoretical path length, determining the planned printing speed of each path point according to the first speed-changing path, the second speed-changing path, and a path printed at a uniform speed with a speed equal to the theoretical printing speed;

[0033] When the path length of the printing sub-path is less than the corresponding shortest theoretical path length, the planned printing speed of each path point is determined according to the starting point printing speed and the ending point printing speed of the printing sub-path.

[0034] Further, when the path length of the printing sub-path is greater than or equal to the corresponding shortest theoretical path length, the process of determining the planned printing speed of each path point according to the first speed-changing path, the second speed-changing path, and the path printed at a uniform speed with a speed equal to the theoretical printing speed includes:

[0035] The difference between the path length of the printing sub-path and the shortest theoretical path length is used as the length of the uniform speed path of the printing sub-path; the path is planned in the order of the first variable speed path, the uniform speed path and the second variable speed path, according to the first variable speed path, the uniform speed path where the instantaneous printing speed of each path point is the theoretical printing speed, and the second variable speed path, and the instantaneous printing speed of each path point on the printing sub-path after path planning is used as the corresponding planned printing speed.

[0036] Furthermore, when the path length of the printing sub-path is less than the corresponding shortest theoretical path length, the process of determining the planned printing speed of each path point according to the starting point printing speed and the ending point printing speed of the printing sub-path includes:

[0037] In the case where the path length of the printing subpath is less than the corresponding shortest theoretical path length, when the starting point printing speed of the printing subpath is less than the ending point printing speed, the starting point printing speed is accelerated to the ending point printing speed by using the a priori maximum printing acceleration as the acceleration, and then printing is performed at a uniform speed according to the ending point printing speed until the path ending point, and the planned printing speed of each path point on the printing subpath is determined;

[0038] When the starting point printing speed of the printing subpath is equal to the ending point printing speed, printing is performed at a uniform speed according to the starting point printing speed until the path ending point, and the planned printing speed of each path point on the printing subpath is determined;

[0039] When the starting printing speed of the printing sub-path is greater than the ending printing speed, the printing path in the process of decelerating the starting printing speed to the ending printing speed with the a priori maximum printing acceleration as the acceleration is used as the supplementary path; the difference between the path length of the printing sub-path and the length of the supplementary path is used as the stable path length; after printing the stable path length at the starting printing speed of the printing sub-path, printing is performed according to the supplementary path to determine the planned printing speed of each path point on the printing sub-path.

[0040] The present application also proposes a 3D printing system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the steps of a 3D printing control method when executing the computer program.

[0041] This application has the following beneficial effects:

[0042] After obtaining all the initial printing paths for each layer of slices of the three-dimensional model of the printed object, the present application divides the initial printing paths into boundary sub-paths and internal sub-paths according to their proximity to the slice boundary, and determines the theoretical printing speed of each printing sub-path based on the characteristics that the contour has a higher requirement for accuracy while the model has a lower requirement for accuracy, combined with the maximum printing speed of the printer.

[0043] The theoretical printing speed is the printing speed under theoretical conditions, that is, when the path type and extension direction in the printing order remain unchanged. Obviously, the implementation environment usually does not conform to the theoretical situation, so further analysis is required based on the theoretical printing speed. For two adjacent printing sub-paths in the printing order, when the printing direction changes significantly, in order to smooth the printing path as much as possible and avoid uneven extrusion of the printing material during the actual printing process, the printing speed needs to be readjusted, and the more obvious the change in the printing direction, the smaller the printing speed should be adjusted. Therefore, this application determines the starting printing speed and the ending printing speed of each printing sub-path based on the path direction angle between adjacent printing sub-paths and the theoretical printing speed of each printing sub-path.

[0044] After determining each printing sub-path, it is necessary to perform path planning based on the planned starting point printing speed and end point printing speed. Usually, the starting point printing speed is accelerated to the theoretical printing speed and then reduced to the end point printing speed after a period of time to end printing. However, considering that the printer's printing adjustment has a reaction time, when the printing time of the path is too short, the theoretical time required to print the path is not enough to maintain the change of the response time, resulting in only one-way adjustment of the printing speed. Therefore, it is also necessary to combine the printer's reaction time, according to the path length of each printing sub-path, the starting point printing speed and the end point printing speed, so as to adaptively determine the planned printing speed of each path point while taking into account printing accuracy and printing efficiency, so that the 3D printing effect is better according to the planned printing speeds of all path points on all printing sub-paths. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0046] Figure 1 A flow chart of a 3D printing control method provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0047] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a 3D printing system and printing control method proposed in accordance with the present invention, its specific implementation method, structure, characteristics and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment, and the specific features, structures or characteristics in one or more embodiments may be combined in any suitable form. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0048] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0049] The specific scheme of a 3D printing system and a printing control method provided by the present invention is described in detail below with reference to the accompanying drawings.

[0050] This application embodiment provides a 3D printing control method, please refer to Figure 1 , which shows a flow chart of a 3D printing control method provided by an embodiment of the present invention, the method comprising:

[0051] Step S101: acquiring all initial printing paths of each slice layer according to the three-dimensional model of the printed object.

[0052] First, after obtaining the three-dimensional model of the printed object with the help of a computer, the slicing software is used to perform layered slicing and determine all initial printing paths. Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining all initial printing paths of each layer of slices according to the three-dimensional model of the printed object includes:

[0053] After setting the 3D model of the printed object in STL format, import it into the slicing software CURA. Use the slicing software CURA to slice the 3D model of the printed object in layers to obtain all the initial printing paths under each layer of slicing. It should be noted that in a specific implementation of an embodiment of the present invention, before determining the initial printing path, the maximum printing speed of the printer, the reaction time of the printer, that is, the a priori reaction time in the subsequent analysis process, and the a priori maximum printing acceleration, that is, the maximum value of the speed adjustment of the printer are obtained in advance; and the above parameters are all inherent parameters of the printer during the implementation process, which need to be obtained by themselves according to the printer situation in the specific implementation environment. In order to make the embodiment complete, this application gives the maximum printing speed in the specific embodiment as , the a priori maximum printing acceleration is set to , the response time is set to 200ms, and no further details will be given later.

[0054] Step S102: Divide each initial printing path into at least one printing sub-path according to the proximity of each initial printing path to the slice boundary; determine the theoretical printing speed of each printing sub-path according to the maximum printing speed of the printer and the path type of each printing sub-path; the path type includes a boundary sub-path and an internal sub-path.

[0055] 3D printing relies on G command files, which are used to control 3D printing. The traditional judgment of printing speed in G command files is a preset fixed value or the same printing speed under the same path. However, the division of the path in the actual process of obtaining the printing path is not accurate, which is manifested in that different positions under the same printing path should have different printing accuracy, and the printing accuracy is related to the printing speed. Therefore, different positions under the same printing path should have different printing speeds, which leads to inaccurate fixed printing speed under G commands. Therefore, it is necessary to divide the path more finely based on different position characteristics under the same path, so as to determine the printing speed of each path point more accurately. The contour of 3D printing has a high demand for accuracy. Therefore, for each position of the path, the closer it is to the slice contour or boundary, the greater the required printing accuracy, and the corresponding speed requirement is usually smaller. Conversely, the farther away from the slice boundary, that is, the closer the path point is to the inside of the model, the smaller the corresponding printing accuracy requirement is usually because it is usually not the external surface of the model or difficult to observe. Therefore, in order to improve printing efficiency, a higher printing speed is usually required. Therefore, first of all, the sub-path can be divided according to the proximity of each initial printing path to the slice boundary, and the theoretical printing speed can be divided based on the path type of the sub-path on the basis of the maximum printing speed of the printer.

[0056] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the printing subpath includes:

[0057] The minimum distance between each path point on each initial printing path and the boundary of the corresponding layer slice is used as the boundary distance of each path point; among all the path points on each initial printing path, the path points with a boundary distance less than the preset distance threshold are used as boundary path points; the path points with a boundary distance greater than the preset distance threshold are used as internal path points; the path points with a boundary distance equal to the preset distance threshold are used as suspected segmentation path points; in the path direction on each initial printing path, the suspected segmentation path points with different path point types of the corresponding previous path points and the corresponding subsequent path points are used as real segmentation path points; with the real segmentation path points as interval points, each initial printing path is divided into at least one printing sub-path. In a specific implementation of an embodiment of the present invention, the preset distance threshold is set to 4mm, which can be adjusted according to the specific implementation environment. The path is divided by the real segmentation path points, so that the divided sub-paths. It should be noted that the embodiment of the present invention treats all the suspected segmentation path points of the non-real segmentation path points that appear continuously as an internal sub-path for subsequent processing to prevent accidental situations from affecting the integrity of the embodiment. And because the internal path points, boundary path points and suspected segmentation path points are divided based on distance, if the path is segmented according to the path point type of two adjacent points, there will always be a single path point type on the segmented sub-path, which is convenient for the subsequent allocation of theoretical printing speed.

[0058] Preferably, in some possible implementations of the embodiments of the present invention, the process of obtaining the theoretical printing speed includes:

[0059] The printing subpaths without internal path points are regarded as boundary subpaths; the other printing subpaths outside the boundary subpaths are regarded as internal subpaths. Since there is a single path point type on the segmented subpaths, the boundary subpaths can also be regarded as printing subpaths with only boundary path points, and the internal subpaths can also be regarded as printing subpaths with only internal path points.

[0060] The maximum printing speed of the printer is used as the theoretical printing speed of the internal sub-path; half of the maximum printing speed of the printer is used as the theoretical printing speed of the boundary sub-path. The internal sub-paths are all internal path points with lower precision requirements, so the corresponding printing speed should be faster; conversely, the boundary sub-paths are all boundary path points with higher precision requirements, so the corresponding printing speed should be slower. It should be noted that the implementer can also use other multiples of the maximum printing speed as the theoretical printing speed according to the specific implementation environment, such as one-third, one-quarter, etc., but it needs to be less than 1, which will not be further elaborated here.

[0061] Step S103: determining the starting point printing speed and the ending point printing speed of each printing subpath according to the path direction angle between adjacent printing subpaths and the theoretical printing speed of each printing subpath.

[0062] The theoretical printing speed is the printing speed under theoretical conditions, that is, when the path type and extension direction in the printing order remain unchanged. Obviously, the implementation environment usually does not conform to the theoretical situation, so further analysis is required based on the theoretical printing speed. For two adjacent printing sub-paths in the printing order, when the printing direction changes significantly, in order to smooth the printing path as much as possible and avoid uneven extrusion of the printing material during the actual printing process, the printing speed needs to be readjusted, and the more obvious the change in the printing direction, the smaller the printing speed should be adjusted; therefore, this application further combines the path direction angle between adjacent printing sub-paths on the basis of the theoretical printing speed to perform the starting point printing speed and the end point printing speed, so as to facilitate the subsequent better speed planning of each path point.

[0063] Preferably, in some possible implementations of the embodiments of the present invention, the process of determining the starting point printing speed and the ending point printing speed of each printing subpath according to the path direction angle between adjacent printing subpaths and the theoretical printing speed of each printing subpath includes:

[0064] Each printing subpath is used as the target subpath in turn; the next printing subpath adjacent to the target subpath in the printing sequence is used as the reference subpath; the angle between the path direction corresponding to the target subpath and the path direction corresponding to the reference subpath is used as the extension change angle of the target subpath. The larger the extension change angle, the greater the change in the printing direction, and the smaller the printing speed should be adjusted at the junction of the printing subpaths, that is, the end position.

[0065] When the extension change angle is greater than the preset directional amplitude threshold, the preset printing speed is set as the end point printing speed of the target sub-path; when the extension change angle is less than or equal to the preset directional amplitude threshold, the product between the negative correlation mapping value of the extension change angle and the theoretical printing speed of the target sub-path is used as the end point printing speed of the target sub-path; the end point printing speed of the target sub-path is used as the starting point printing speed of the reference sub-path. In a specific implementation of an embodiment of the present invention, the preset directional amplitude threshold is set to 90 degrees, and the preset printing speed is set to 0, which can be adjusted according to the specific implementation environment. Considering that the printing path formed when the extension change angle is greater than 90 degrees is usually not effectively smooth, when the extension change angle is greater than 90 degrees, the preset printing speed is set to 0, that is, after the printing speed is reduced to 0 at the end of the sub-path, the next path is printed. When the extension change angle is less than or equal to 90 degrees, the larger the extension change angle is, the smaller the printing speed should be adjusted at the junction of the printing sub-paths, that is, the end point. After the extension change angle is negatively correlated with the theoretical printing speed of the target sub-path, a product operation is performed to determine the reduced end point printing speed to improve the printing effect. In a specific implementation of the embodiment of the present invention, the process of obtaining the end point printing speed includes: ;in, The target subpath The end printing speed, that is, the target subpath The starting printing speed of the corresponding reference subpath; The target subpath The angle between the corresponding path direction and the path direction corresponding to the corresponding reference subpath, that is, the target subpath The corresponding extension change angle; is the preset direction amplitude threshold; is the preset printing speed; It is a linear normalization function, and the normalization method can be adjusted according to the specific implementation environment; The target subpath Corresponding theoretical printing speed. It should be noted that, considering that the first printing subpath does not have a previous printing subpath, the embodiment of the present invention sets the starting printing speed of the first printing subpath to 0, which can be adjusted according to the specific implementation environment.

[0066] Step S104: determining the planned printing speed of each path point on each printing sub-path according to the path length, the starting point printing speed and the ending point printing speed of each printing sub-path.

[0067] After determining each printing sub-path, it is necessary to carry out path planning based on the planned starting point printing speed and end point printing speed. Usually, the starting point printing speed is accelerated to the theoretical printing speed and then reduced to the end point printing speed after a period of time to end printing. However, considering that the printer's printing adjustment has a reaction time, when the printing time of the path is too short, the theoretical time required to print the path is not enough to maintain the change of the response time, resulting in only one-way adjustment of the printing speed. Therefore, it is also necessary to combine the printer's reaction time, according to the path length, starting point printing speed and end point printing speed of each printing sub-path, so as to adaptively determine the planned printing speed for each path point while taking into account printing accuracy and printing efficiency.

[0068] Preferably, the process of obtaining the planned printing speed includes:

[0069] Under the condition of constant acceleration, the theoretical printing time of each printing subpath is determined according to the path length, the starting printing speed and the ending printing speed of each printing subpath; the priori reaction time and the priori maximum printing acceleration of the printer are obtained. In a specific implementation of the embodiment of the present invention, the process of obtaining the theoretical printing time is expressed by the formula: ;in, For the Layer slice Theoretical printing time of a printing subpath; For the Layer slice The path length of the printed subpath; For the Layer slice The starting printing speed of a printing subpath; For the Layer slice The terminal printing speed of a printing sub-path. It should be noted that the calculation of time under the condition of constant acceleration and known initial speed, final speed and distance is a commonly used mathematical means, that is, a technical means well known to those skilled in the art, which will not be further elaborated here. It should be noted that when the printing sub-path is too short and the a priori maximum printing acceleration of the printer is insufficient to support the acceleration of the corresponding printing sub-path from the starting printing speed to the terminal printing speed, the printing sub-path is printed at a uniform speed at the starting printing speed, so as to make the embodiment of the present application more complete and reduce the influence of accidental factors. It should be noted that the a priori maximum printing acceleration in the embodiment of the present invention does not include direction, that is, the corresponding a priori maximum printing acceleration in the direction of deceleration and acceleration is the same, which will not be further elaborated here.

[0070] Under each printing sub-path, when half of the theoretical printing time is less than or equal to the prior reaction time, the planned printing speed of each path point under constant acceleration is obtained. When half of the theoretical printing time is less than the prior reaction time, due to the relatively large prior reaction time, the theoretical time required to print the path is insufficient to maintain the change of the reaction time, so that the actual printing speed at the end point does not match the theoretical printing speed, resulting in an imbalance in the printing system and an abnormality. Therefore, the printing speed of the corresponding printing sub-path can only be adjusted in one direction, and cannot increase, maintain stability or decrease at the same time under this path; therefore, printing starts at the starting point printing speed at the starting point of the corresponding printing sub-path, and printing is continued under constant acceleration, so that the printing of the printing sub-path is completed when accelerating to the corresponding end point printing speed, that is, the corresponding theoretical printing time is the final printing time of the printing sub-path. It should be noted that, when the distance, time, initial velocity, final velocity and acceleration are known, calculating the speed of each point in the path is a commonly used mathematical operation method, which will not be further elaborated here.

[0071] When half of the theoretical printing time is greater than the a priori reaction time, the planned printing speed for each path point under the uniform speed path is obtained. When half of the theoretical printing time is greater than the a priori reaction time, it means that the a priori reaction time is relatively too small, indicating that there is sufficient reaction time under the printing sub-path. Therefore, when 3D printing the road section, the printing speed can be adjusted to shorten the printing time as much as possible and improve the printing efficiency. First of all, it is known that the starting printing speed and the end printing speed are both adjusted downward on the basis of the theoretical printing speed, that is, the starting printing speed and the end printing speed are always less than or equal to the theoretical printing speed. Therefore, in an environment with adjustable speed, to achieve the highest printing speed, then in theory, it is necessary to first adjust the starting printing speed to the theoretical printing speed and then perform uniform printing, and finally reduce it to the end printing speed to complete the printing of the printing sub-path just in time to achieve the maximum printing efficiency.

[0072] Preferably, when half of the theoretical printing time is greater than the a priori reaction time, the process of obtaining the planned printing speed of each path point under the uniform speed path includes:

[0073] When half of the theoretical printing time is greater than the a priori reaction time, the first speed change path of each printing subpath is determined according to the starting printing speed of each printing subpath under the constant a priori maximum printing acceleration and the theoretical printing speed after acceleration; the second speed change path of each printing subpath is determined according to the theoretical printing speed of each printing subpath under the constant a priori maximum printing acceleration and the terminal printing speed after deceleration; the shortest theoretical path length of each printing subpath is determined according to the sum of the length of the first speed change path and the length of the second speed change path of each printing subpath; wherein the first speed change path and the second speed change path both include the instantaneous printing speed at each path point. In order to improve printing efficiency, the duration of the theoretical printing speed should be as long as possible, so the acceleration during speed adjustment needs to be as fast as possible; therefore, the shortest first speed change path and the second speed change path are determined by the a priori maximum printing acceleration, which also shows that the premise for the existence of a theoretical printing speed for uniform speed printing is that the length of the corresponding printing subpath needs to be greater than the sum of the first speed change path and the second speed change path, that is, it needs to be greater than the shortest theoretical path length. When the path length of the printing sub-path is greater than or equal to the corresponding shortest theoretical path length, the planned printing speed of each path point is determined according to the first variable speed path, the second variable speed path and the path of uniform printing at the theoretical printing speed. That is, at this time, it is necessary to comprehensively consider the uniform printing process of the theoretical printing speed.

[0074] Preferably, in some possible implementations of the embodiments of the present invention, when the path length of the printing sub-path is greater than or equal to the corresponding shortest theoretical path length, the process of determining the planned printing speed of each path point according to the first variable speed path, the second variable speed path, and the path printed at a uniform speed with a speed equal to the theoretical printing speed includes:

[0075] The difference between the path length of the printing sub-path and the shortest theoretical path length is used as the length of the uniform speed path of the printing sub-path; the path is planned in the order of the first variable speed path, the uniform speed path and the second variable speed path, according to the first variable speed path, the uniform speed path where the instantaneous printing speed of each path point is the theoretical printing speed, and the second variable speed path, and the instantaneous printing speed of each path point on the printing sub-path after path planning is used as the corresponding planned printing speed. When the path length of the printing subpath is greater than or equal to the corresponding shortest theoretical path length, the printing process of the corresponding printing subpath should be in the order of the first speed change path, the uniform speed path and the second speed change path. The corresponding first speed change path is the path printed in the process of accelerating from the starting printing speed to the theoretical printing speed at a constant a priori maximum printing acceleration, the corresponding uniform speed path is the path printed at a constant a priori maximum printing acceleration at the theoretical printing speed, and the second speed change path is the path accelerated from the theoretical printing speed to the end printing speed at a constant a priori maximum printing acceleration; therefore, on the entire printing subpath, the instantaneous printing speed of each path point can be directly obtained, so the instantaneous printing speed of each path point on the printing subpath is finally used as the corresponding planned printing speed. It should be noted that in all the acceleration processes in the embodiments of the present invention, the specific acceleration and deceleration need to be determined according to the size of the initial speed and the final speed in the implementation environment. When the initial speed is greater than the final speed, acceleration is required, and vice versa, when the initial speed is less than the final speed, deceleration is required. In the specific implementation environment, acceleration or deceleration needs to be adjusted according to the specific implementation environment, which will not be further elaborated here.

[0076] When the path length of the printing subpath is less than the corresponding shortest theoretical path length, the planned printing speed of each path point is determined according to the starting point printing speed and the end point printing speed of the printing subpath. If the path length of the printing subpath is less than the corresponding shortest theoretical path length, it means that there is no uniform printing process at the theoretical printing speed, because the path length is not enough to maintain two speed adjustment processes, so it is necessary to further perform more specific path planning according to the specific situation. Preferably, in some possible implementation methods of the embodiments of the present invention, when the path length of the printing subpath is less than the corresponding shortest theoretical path length, the process of determining the planned printing speed of each path point according to the starting point printing speed and the end point printing speed of the printing subpath includes:

[0077] When the path length of the print subpath is less than the corresponding shortest theoretical path length, when the print speed at the start of the print subpath is less than the print speed at the end, the a priori maximum print acceleration is used as the acceleration, and after the start print speed is accelerated to the end print speed, the uniform speed printing is performed according to the end print speed until the end of the path, and the planned print speed of each path point on the print subpath is determined. When the path length of the print subpath is less than the corresponding shortest theoretical path, since two speed adjustments are not supported, one speed adjustment is set for printing. Since there is only one speed adjustment opportunity, under the condition of maximum printing efficiency, the larger printing speed between the starting printing speed and the end printing speed should be used for uniform printing. At this time, it is necessary to analyze the relative size of the starting printing speed and the end printing speed. When the starting printing speed is less than the end printing speed, uniform printing should be performed at the end printing speed. Therefore, the corresponding speed adjustment should be to adjust the starting printing speed to the end printing speed, and then perform uniform printing according to the end printing speed until the end of the path. The acceleration during the entire acceleration process is constant, and the starting printing speed and the end printing speed are both known. Therefore, the instantaneous printing speed of all path points on the corresponding printing sub-path, that is, the planned printing speed, is also known.

[0078] When the print speed at the start point of the print subpath is equal to the print speed at the end point, the print is performed at a uniform speed until the end point according to the print speed at the start point, and the planned print speed for each path point on the print subpath is determined. The print speed at the start point is equal to the print speed at the end point, which means that no speed adjustment is required, so the print is performed at a uniform speed, and the planned print speed for each path point is the print speed at the start point, which is also the print speed at the end point.

[0079] When the starting printing speed of the printing subpath is greater than the end printing speed, the printing path in the process of decelerating the starting printing speed to the end printing speed with the a priori maximum printing acceleration as the acceleration is used as the supplementary path; the difference between the path length of the printing subpath and the length of the supplementary path is used as the stable path length; after printing the stable path length at the starting printing speed of the printing subpath, printing is performed according to the supplementary path to determine the planned printing speed of each path point on the printing subpath. When the starting printing speed is greater than the end printing speed, it means that the speed of the corresponding uniform printing process should be the starting printing speed, that is, it is necessary to first print at a uniform speed at the starting printing speed, and start to decelerate after printing to a certain position, so that the printing is completed just after decelerating to the end printing speed; so the position where deceleration starts needs to be determined first; therefore, by calculating the supplementary path length printed in the process of decelerating from the starting printing speed to the end printing speed, the stable path length obtained by subtracting the length of the supplementary path from the path length of the printing subpath is more accurate, and the corresponding stable path length is also the path length of uniform printing at the starting printing speed. That is, the overall printing process of the entire printing sub-path is to print a stable path length at a uniform speed at the starting point printing speed, and then decelerate the starting point printing speed to the end point printing speed with the prior maximum printing acceleration to complete the printing; the acceleration during the entire deceleration process is constant, and the starting point printing speed and the end point printing speed are both known, so the instantaneous printing speed of all path points on the corresponding printing sub-path, that is, the planned printing speed, is also known.

[0080] At this point, the planned printing speeds of all path points on all printing sub-paths are determined.

[0081] Step S105: performing 3D printing control according to the planned printing speeds of all path points on all printing sub-paths.

[0082] Finally, the printing process is adjusted according to the planned printing speed of each path point on each printing sub-path that has been obtained, so that the printer prints according to the planned printing path and the planned printing speed of each path point, so that the entire printing process takes into account both printing accuracy and printing efficiency, thereby improving the accuracy and efficiency of 3D printing.

[0083] To summarize, according to the characteristic of the contour having a high demand for accuracy, the present application divides the boundary sub-path and the internal sub-path according to the proximity of the printing path to the slice and determines the corresponding theoretical printing speed, and then determines the starting printing speed and the ending printing speed of each printing sub-path in combination with the characteristic that the directional change between the printing sub-paths will affect the printing effect, and further performs further path planning in combination with the path length of each printing sub-path, so as to adaptively determine the planned printing speed for each path point while taking into account the printing accuracy and printing efficiency, solving the problem that the accuracy and efficiency of each position cannot be taken into account when printing at a fixed printing speed, so that the accuracy and efficiency of 3D printing according to the planned printing speed of all path points on all printing sub-paths are higher.

[0084] The present application also proposes a 3D printing system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the steps of a 3D printing control method when executing the computer program.

[0085] It should be noted that the sequence of the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0086] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A 3D printing control method, characterized in that: The method comprises: Obtain all initial printing paths for each slice according to the three-dimensional model of the printed object; Divide each initial printing path into at least one printing subpath according to the proximity of each initial printing path to a slice boundary; determine a theoretical printing speed of each printing subpath according to a maximum printing speed of the printer and a path type of each printing subpath; the path type includes a boundary subpath and an internal subpath; Determine the starting point printing speed and the ending point printing speed of each printing subpath according to the path direction angle between adjacent printing subpaths and the theoretical printing speed of each printing subpath; Determining the planned printing speed of each path point on each printing subpath according to the path length of each printing subpath, the starting point printing speed and the end point printing speed; 3D printing control is performed according to the planned printing speed of all path points on all printing sub-paths; The process of obtaining all initial printing paths of each slice according to the three-dimensional model of the printed object includes: The three-dimensional model of the printed object is set to STL format and then imported into the slicing software CURA, and the three-dimensional model of the printed object is sliced ​​into layers by the slicing software CURA to obtain all initial printing paths under each layer of slices; The process of obtaining the printing subpath includes: The minimum distance between each path point on each initial printing path and the boundary of the corresponding layer slice is taken as the boundary distance of each path point; Among all the path points on each initial printing path, the path points whose boundary distance is less than the preset distance threshold are regarded as boundary path points; the path points whose boundary distance is greater than the preset distance threshold are regarded as internal path points; and the path points whose boundary distance is equal to the preset distance threshold are regarded as suspected segmentation path points; In the path direction on each initial printing path, the suspected segmentation path points whose path point types of the corresponding previous path points and the corresponding next path points are different are taken as the real segmentation path points; Using the real segmentation path points as interval points, each initial printing path is divided into at least one printing sub-path; The process of obtaining the theoretical printing speed includes: The printing subpath without internal path points is regarded as the boundary subpath; the other printing subpaths outside the boundary subpath are regarded as internal subpaths; The maximum printing speed of the printer is used as the theoretical printing speed of the internal sub-path; half of the maximum printing speed of the printer is used as the theoretical printing speed of the boundary sub-path; The process of determining the starting point printing speed and the ending point printing speed of each printing subpath according to the path direction angle between adjacent printing subpaths and the theoretical printing speed of each printing subpath comprises: Each printing sub-path is used as a target sub-path in turn; the next printing sub-path adjacent to the target sub-path in the printing sequence is used as a reference sub-path; The included angle between the path direction corresponding to the target subpath and the path direction corresponding to the reference subpath is used as the extension change angle of the target subpath; When the extension change angle is greater than a preset direction amplitude threshold, setting the preset printing speed as the end point printing speed of the target sub-path; When the extension change angle is less than or equal to a preset direction amplitude threshold, the product of the negative correlation mapping value of the extension change angle and the theoretical printing speed of the target sub-path is used as the terminal point printing speed of the target sub-path; The printing speed at the end point of the target sub-path is used as the printing speed at the start point of the reference sub-path; The process of obtaining the planned printing speed includes: Under the condition of constant acceleration, the theoretical printing time of each printing sub-path is determined according to the path length, the starting point printing speed and the end point printing speed of each printing sub-path; the priori reaction time and the priori maximum printing acceleration of the printer are obtained; Under each printing subpath, when half of the theoretical printing time is less than or equal to the priori reaction time, the planned printing speed of each path point under constant acceleration is obtained; when half of the theoretical printing time is greater than the priori reaction time, the planned printing speed of each path point under the uniform speed path is obtained; When half of the theoretical printing time is greater than the priori reaction time, the process of obtaining the planned printing speed of each path point under the uniform speed path includes: When half of the theoretical printing time is greater than the a priori reaction time, a first speed change path of each printing subpath is determined according to the starting printing speed of each printing subpath under a constant a priori maximum printing acceleration and the theoretical printing speed after acceleration; a second speed change path of each printing subpath is determined according to the theoretical printing speed of each printing subpath under a constant a priori maximum printing acceleration and the end printing speed after deceleration; a shortest theoretical path length of each printing subpath is determined according to the sum of the length of the first speed change path and the length of the second speed change path of each printing subpath; wherein the first speed change path and the second speed change path both include the instantaneous printing speed at each path point; When the path length of the printing sub-path is greater than or equal to the corresponding shortest theoretical path length, determining the planned printing speed of each path point according to the first speed-changing path, the second speed-changing path, and a path printed at a uniform speed with a speed equal to the theoretical printing speed; When the path length of the printing sub-path is less than the corresponding shortest theoretical path length, the planned printing speed of each path point is determined according to the starting point printing speed and the ending point printing speed of the printing sub-path.

2. A 3D printing control method according to claim 1, characterized in that: The process of determining the planned printing speed of each path point according to the first speed-changing path, the second speed-changing path, and the path of uniform printing at the theoretical printing speed when the path length of the printing sub-path is greater than or equal to the corresponding shortest theoretical path length comprises: The difference between the path length of the printing sub-path and the shortest theoretical path length is used as the length of the uniform speed path of the printing sub-path; the path is planned in the order of the first variable speed path, the uniform speed path and the second variable speed path, according to the first variable speed path, the uniform speed path where the instantaneous printing speed of each path point is the theoretical printing speed, and the second variable speed path, and the instantaneous printing speed of each path point on the printing sub-path after path planning is used as the corresponding planned printing speed.

3. A 3D printing control method according to claim 1, characterized in that: The process of determining the planned printing speed of each path point according to the starting point printing speed and the ending point printing speed of the printing subpath when the path length of the printing subpath is less than the corresponding shortest theoretical path length includes: In the case where the path length of the printing subpath is less than the corresponding shortest theoretical path length, when the starting point printing speed of the printing subpath is less than the ending point printing speed, the starting point printing speed is accelerated to the ending point printing speed by using the a priori maximum printing acceleration as the acceleration, and then printing is performed at a uniform speed according to the ending point printing speed until the path ending point, and the planned printing speed of each path point on the printing subpath is determined; When the printing speed of the starting point of the printing subpath is equal to the printing speed of the ending point, printing is performed at a uniform speed according to the printing speed of the starting point until the end point of the path, and the planned printing speed of each path point on the printing subpath is determined; When the starting printing speed of the printing sub-path is greater than the ending printing speed, the printing path in the process of decelerating the starting printing speed to the ending printing speed with the a priori maximum printing acceleration as the acceleration is used as the supplementary path; the difference between the path length of the printing sub-path and the length of the supplementary path is used as the stable path length; after printing the stable path length at the starting printing speed of the printing sub-path, printing is performed according to the supplementary path to determine the planned printing speed of each path point on the printing sub-path.

4. A 3D printing system, characterized in that: The method comprises a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of a 3D printing control method as claimed in any one of claims 1 to 3 when executing the computer program.

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