A 3D printer hot bed leveling method, device, storage medium and 3D printer

Abstract

The application discloses a kind of 3D printer's hot bed leveling method, this method includes: obtaining the plane coordinate of hot bed center point and the mapping point of limit switch in hot bed plane of 3D printer, select a reference point, according to the coordinate ratio of hot bed center point to reference point, limit switch mapping point, the Z axis adjustment amount of limit switch is obtained by calculation;According to the Z axis adjustment amount of limit switch, the zero height value in limit switch is adjusted, so that the plane formed by the zero of limit switch is relatively parallel with the hot bed plane;N*n matrix test points are set on the hot bed to detect, the Z value of any point on the hot bed is according to the distance relationship of the four matrix test points closest to it, and the global three-dimensional coordinates of the hot bed in the space of 3D printer are calculated.The application solves the problem of hot bed inclination and local unevenness, effectively improves the printing precision of 3D printing products.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of additive manufacturing technology, in particular to a 3D printer hot bed leveling method and device, a storage medium and a 3D printer. BACKGROUND

[0002] 3D printing technology is a kind of rapid prototyping technology, which is a technology for manufacturing entities by gradually accumulating materials. With the development of science and technology, 3D printers play an increasingly important role in our production and life. The hot bed leveling of the 3D printer can ensure the effect and precision of the printer. Therefore, before the 3D printer works, the hot bed of the printer needs to be adjusted, that is, to ensure that the distance from the printing nozzle to any point of the hot bed is equal.

[0003] At present, for the hot bed leveling technology, semi-automatic leveling can be selected, the height error existing in the hot bed installation structure is automatically detected, and the operator adjusts the relative distance between the hot bed support points and the nozzle by rotating the hot bed four corner leveling nuts in sequence, so as to achieve accurate leveling effect. However, the manual adjustment method is not only time-consuming and laborious, but also the parts around the hot bed or the center not supported may be warped and slightly deformed due to uneven force of the nut tightness, which makes it difficult to ensure the accuracy and stability of the leveling. For enterprises with high printing precision requirements, a horizontal base can be created by analyzing and calculating the height difference of the hot bed plane for printing compensation, such as the inclined road compensation device and method for FDM type 3D printer platform disclosed in the invention patent with the announcement number CN107379530A. However, if the angle of the hot bed inclination is found, the 3D printer is not adjusted, and the product model is still printed on the hot bed, the bottom of the product model will also be inclined with the hot bed, which still cannot meet the printing precision.

[0004] In addition, the detection method of the hot bed leveling of the 3D printer is mostly to directly connect the pressure sensor with the nozzle for pressure measurement, and then to level the hot bed. During the leveling process, with the continuous movement of the nozzle, the pressure on the pressure sensor will fluctuate, resulting in inaccurate pressure value measurement. Or there are local concave-convex parts on the hot bed, if the printing height of the 3D printer nozzle is not adjusted in time, it will also cause wear of the nozzle, and then result in poor printing quality. Therefore, it is necessary to solve the problems existing in the above-mentioned prior art. SUMMARY

[0005] In order to overcome the problems in the prior art, the purpose of the present application is to provide a 3D printer hot bed leveling method, which can effectively solve the problems of inclination and unevenness existing on the surface of the 3D printer hot bed, realize automatic detection and leveling of the 3D printer hot bed, and improve the quality of 3D printed products.

[0006] To achieve the above object, the application provides a 3D printer hot bed leveling method, comprising:

[0007] A space rectangular coordinate system is established with the hot bed center as the origin, the plane coordinates of each limit switch mapping point on the hot bed plane and the plane coordinates of the hot bed center point are obtained, a reference point is selected between each limit switch mapping point on the hot bed plane and the hot bed center point within the hot bed printing range, the plane coordinates of each reference point are obtained, the hot bed center point and each reference point are detected, and the Z value coordinates of the hot bed center point and each reference point are obtained;

[0008] The Z axis adjustment amount of each limit switch is calculated according to the distance from the hot bed center point to the reference point, the distance from the hot bed center point to the limit switch mapping point, and the Z value difference between the reference point and the hot bed center point;

[0009] The height value of each limit switch is adjusted according to the Z axis adjustment amount of each limit switch, so that the plane formed by the zero return control motor is relatively parallel to the hot bed plane;

[0010] n*n matrix test points (n≥2) are set on the hot bed plane for detection, and the three-dimensional coordinates of the n*n matrix test points in the 3D printer space are obtained through detection;

[0011] The Z value of the real-time printing coordinate point of the 3D printer on the hot bed is calculated according to the distance relationship of the four closest matrix test points.

[0012] Preferably, the hot bed center point, the reference point and the matrix test point are the to-be-tested points, and the detection method is as follows: a pressure sensor is installed under the hot bed, the printing nozzle is first moved to the XY coordinate intersection point in parallel according to the plane coordinates of the to-be-tested point, and then vertically downward along the Z axis direction until the printing nozzle moves to contact the hot bed plane, the pressure signal of the pressure sensor changes, the Z axis movement distance of the printing nozzle is recorded at the moment of the pressure signal change, the Z axis movement distance of the printing nozzle is converted into the Z value coordinate of the to-be-tested point, and the three-dimensional coordinates of the to-be-tested point are obtained.

[0013] Preferably, an allowable error range of the Z value difference of the to-be-tested point detected for two times in succession is set, the Z value of the to-be-tested point is recorded after the first detection, the same to-be-tested point is detected for the second time, the difference between the Z values measured for two times in succession is calculated, and it is judged whether the Z value difference of the to-be-tested point is within the error range; if the Z value difference of the to-be-tested point is within the error range, the detection of the next to-be-tested point is performed; if the Z value difference of the to-be-tested point exceeds the error range, the detection of the to-be-tested point is continuously triggered until the Z value difference of the to-be-tested point measured for two times in succession is within the error range; and the average value of the Z values within the error range for two times in succession is taken as the Z value of the to-be-tested point.

[0014] Preferably, the method for calculating the Z-axis adjustment amount of each limit switch is:

[0015] obtaining the coordinates (Xo, Yo, Zo) of the center point O of the hot bed after detection, the coordinates (X I , Y I ) of the limit switch mapping points, the coordinates (X i , Y i , Z i ) of the reference points between the limit switch mapping points and the center point of the hot bed, and setting the Z-axis adjustment amount of the limit switch as Z I ;

[0016] calculating the distance from the center point O of the hot bed to the reference point as the distance from the center point O of the hot bed to the limit switch mapping point as

[0017] the Z-axis adjustment amount of the limit switch is:

[0018] Preferably, the method for setting n*n matrix test points (n≥2) on the hot bed is specifically:

[0019] the rectangle composed of the n*n matrix test points (n≥2) is the circumscribed rectangle of the circular hot bed;

[0020] the matrix test point beyond the printing range of the hot bed takes the point closest to it in the printing range of the hot bed as a substitute point for detection.

[0021] Preferably, the method for calculating the Z value of the real-time printing coordinate point on the hot bed of the printer is specifically: setting the real-time printing coordinate point on the hot bed as P5, and the four matrix test points closest to P5 as P1, P2, P3, and P4.

[0022] obtaining the XY coordinates of the real-time printing coordinate point P5 on the hot bed, and obtaining the distances from the four matrix test points P1, P2, P3, and P4 closest to P5 to P5 according to the XY coordinates of P5;

[0023] calculating the influence factors q1, q2, q3, and q4 of each point according to the principle that the closer the distance from P5 to P1, P2, P3, and P4, the greater the influence factor of the Z value of P1, P2, P3, and P4;

[0024] assigning the product of the Z value of P1, P2, P3, and P4 and the influence factor to the Z value of P5.

[0025] Preferably, the method for calculating the influence factors q1, q2, q3, and q4 of each point is:

[0026] According to the smaller the distance ratio of the points P1, P2, P3, P4 and P5, the greater the multiplication influence factor of the Z values of P1, P2, P3 and P4, and according to the greater the distance ratio of the points P1, P2, P3, P4 and P5, the smaller the multiplication influence factor of the Z values of P1, P2, P3 and P4.

[0027] The application also provides a 3D printer hot bed leveling device, which is used for implementing the 3D printer hot bed leveling method.

[0028] The acquisition module is configured to acquire the coordinates of the limit switch mapping points and the coordinates of the detection test points.

[0029] The storage module is configured to store the 3D printer parameters, the coordinates of the detection test points and the limit switch Z-axis adjustment amount.

[0030] The control module is configured to drive the printing nozzle.

[0031] The detection module comprises a pressure sensor and is configured to feed back a signal of a change in the pressure value borne by the hot bed.

[0032] The processing module is configured to calculate the Z value of the real-time coordinate point and the limit switch Z-axis adjustment amount according to the matrix test point coordinate value.

[0033] The application also provides a computer readable storage medium configured to store a computer program, wherein the computer program enables a computer to execute the 3D printer hot bed leveling method.

[0034] The application also provides a 3D printing device, which comprises the 3D printer hot bed leveling device.

[0035] Compared with the prior art, the application can accurately feed back the change in the pressure borne by the pressure sensor during the detection process, and then quickly feed back the Z-axis coordinate of the test point, because the mass on the hot bed is stable. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The application also provides a 3D printer hot bed leveling method flowchart for the embodiment 1.

[0037] Figure 2 A 3D printer hot bed leveling method flow chart provided for the embodiment 2 of the present application;

[0038] Figure 3 A 3D printer hot bed leveling method flow chart provided for the embodiment 3 of the present application;

[0039] Figure 4 A 3D printer hot bed leveling method provided by the present application, the schematic diagram of the column, reference point and hot bed center point;

[0040] Figure 5 A 3D printer hot bed leveling method provided by the present application, the schematic diagram of the limit switch after adjustment and hot bed position;

[0041] Figure 6 A 3D printer hot bed leveling method provided by the present application, the schematic diagram of the matrix test point;

[0042] Figure 7 A 3D printer hot bed leveling method provided by the present application, the schematic diagram of the matrix test point of the circular hot bed;

[0043] Figure 8 A 3D printer hot bed leveling method provided by the present application, the coordinate schematic diagram of the matrix test point P1, P2, P3, P4, P5;

[0044] Figure 9 A 3D printer hot bed leveling device structure schematic diagram provided for the embodiment 1 of the present application;

[0045] BRIEF DESCRIPTION OF DRAWINGS: 1, hot bed; 2, nozzle; 3, column. DETAILED DESCRIPTION

[0046] Embodiment 1:

[0047] The embodiment provides a 3D printer hot bed leveling method, as shown in the specific method: Figure 1 The specific method is:

[0048] The space rectangular coordinate system is established with the hot bed center as the origin, the plane coordinates of each limit switch in the hot bed plane mapping point and the plane coordinates of the hot bed center point are obtained, in the hot bed printing range, each limit switch in the hot bed plane mapping point is selected to a reference point between the hot bed center point, the plane coordinates of each reference point are obtained, the hot bed center point and the reference point are detected, and the Z value coordinates of the hot bed center point and the reference point are obtained;

[0049] Specifically, taking the parallel-arm 3D printer as an example in this embodiment, the parallel-arm 3D printer is provided with at least three limit switches for limiting the control motor. The limit switches are respectively installed on three columns of the 3D printer, namely column A', column B', and column C'. According to the model of the 3D printer, a space rectangular coordinate system is established with the center point O of the hot bed as the origin, and the plane coordinates of the center point O of the hot bed are obtained as (0, 0), the printing radius of the hot bed is R, and the distance between the column and the center point O of the hot bed is R'. The coordinates of the mapping points of the columns on the hot bed plane are column A'(0, sin90R'), column B'(sin60R', -sin30R'), and column C'(-sin60R', -sin30R') respectively. The coordinates of the mapping points of the limit switches on the hot bed plane are also limit switch mapping point A(0, sin90R'), limit switch mapping point B(sin60R', -sin30R'), and limit switch mapping point C(-sin60R', -sin30R'). A reference radius r is set, where r < R. A reference point is respectively determined on the reference radius r on the hot bed surface according to the coordinates of limit switch mapping point A, limit switch mapping point B, and limit switch mapping point C, so that the reference point is on the connection line between the limit switch mapping point and the center point of the hot bed. The coordinates of the reference points are: reference point a(0, sin90r), reference point b(sin60r, -sin30r), and reference point c(-sin60r, -sin30r).

[0050] After obtaining the coordinates of the center point of the hot bed, the reference point, and the mapping point of the limit switch of the 3D printer, the points on the hot bed surface are detected, that is, the center point of the hot bed and the reference point are detected.

[0051] A pressure sensor is installed under the hot bed. Taking the detection of reference point a as an example, the printing nozzle first moves parallel to the coordinate intersection point of (0, sin90r) according to the coordinates of reference point a, and then moves vertically downward along the Z-axis direction until the printing nozzle moves to contact the hot bed plane. At this moment, the pressure sensor under the hot bed senses that the pressure signal changes. The moving distance of the printing nozzle along the Z-axis is recorded at the moment when the pressure signal changes, and the moving distance of the printing nozzle along the Z-axis is converted into the Z-axis coordinate Z of reference point a a1 .

[0052] In order to avoid debris or other reasons on the hot bed from affecting the detection accuracy, the same point can be detected multiple times. First, set the difference error range of the allowable Z value of reference point a. After the first detection, record the Z-axis coordinate of reference point a as Z a1 ; detect reference point a again. After the second detection, record the Z-axis coordinate of reference point a as Z a2; calculate the difference between the two consecutive Z values, determine whether the difference of the Z value of the reference point a is within the error range; if the difference of the Z value of the reference point a detected twice exceeds the allowable error range, continue to trigger the detection of the reference point a until the difference of the Z value of the reference point a detected twice is within the error range; if the height difference of the Z value of the reference point a detected twice is within the error range, the average value of the Z value within the error range As the Z value of the reference point a, the three-dimensional coordinates (0, sin90r, Z a ) of the reference point a are obtained, and the detection of the next reference point is continued.

[0053] According to the coordinate ratio of the center point of the hot bed to the reference point and the limit switch mapping point, the Z-axis adjustment amount of the limit switch is calculated.

[0054] Specifically, the method for calculating the Z-axis adjustment amount of the limit switch is:

[0055] The coordinates (0, 0, Zo) of the hot bed center point O obtained after detection, the coordinates (0, sin90R') of the limit switch mapping point A, and the coordinates (0, sin90r, Za) of the reference point a between the limit switch mapping point and the hot bed center point are obtained, and the Z-axis adjustment amount of the limit switch is set as Z A .

[0056] The distance from the hot bed center point O to the reference point a is calculated as The distance from the hot bed center point to the limit switch mapping point is

[0057] The Z-axis adjustment amount of the limit switch is

[0058] Repeat the above process until the Z-axis adjustment amount of all limit switches of the 3D printer is calculated.

[0059] According to the Z-axis adjustment amount of each limit switch, the height value of the limit switch is adjusted, so that the plane formed by the control motor zero position is relatively parallel to the hot bed plane.

[0060] When the plane formed by the control motor zero position is relatively parallel to the hot bed plane, the rough adjustment of the hot bed of the 3D printer is completed. After the Z-axis adjustment amount of the limit switch is adjusted, the space coordinates between the plane formed by the control motor zero position inside the 3D printer and the hot bed plane change again, and there may be some concave and convex areas on the surface of the hot bed. In order to avoid errors during printing, the global coordinates of the hot bed surface need to be detected again.

[0061] A 7*7 matrix test point is set on the hot bed for detection, and the three-dimensional coordinates of the 7*7 matrix test point in the printer space are detected.

[0062] Specifically, for a rectangular hot bed, as shown in FIG. 1, in order to improve the accuracy of detecting the global coordinates of the hot bed surface, 7*7 matrix test points are uniformly distributed in the printing range of the 3D printer hot bed. Figure 6

[0063] Specifically, for a circular hot bed, as shown in FIG. 2, the method for processing the matrix test points is as follows: Figure 7

[0064] The rectangle composed of the 7*7 matrix test points is the circumscribed rectangle of the circular hot bed.

[0065] The matrix test points that are outside the printing range of the hot bed take the points closest to them within the printing range of the hot bed as substitute points for detection.

[0066] By shrinking the matrix test points that are outside the range of the circular hot bed into the printing range of the hot bed, the density of the detection points at the edge of the hot bed is enriched.

[0067] After detection, the three-dimensional coordinates of the 7*7 matrix test points are obtained. The method for detecting the 7*7 matrix test points is as described above, and will not be repeated here.

[0068] The Z value of the real-time printing coordinate point of the 3D printer on the hot bed is calculated according to the distance relationship with the four closest matrix test points.

[0069] Specifically, as shown in FIG. 3, let the real-time printing coordinate point of the 3D printer on the hot bed be P5, the coordinates of P5 be (X5, Y5, Z5), Z5 be an unknown number, and the four closest matrix test points to P5 be P1, P2, P3, P4 in order from near to far. Figure 8

[0070] The XY coordinates of the real-time printing coordinate point P5 on the hot bed are obtained, the four closest matrix test points P1, P2, P3, P4 to P5 are obtained according to the XY coordinates of P5, and the distances from P5 are calculated respectively; let the coordinates of P5 be (X5, Y5, Z5), the coordinates of P1 be (X1, Y1, Z1), the coordinates of P2 be (X2, Y2, Z2), the coordinates of P3 be (X3, Y3, Z3), and the coordinates of P4 be (X4, Y4, Z4).

[0071] The distances from P5 to P1, P2, P3, P4 are calculated to be k1, k2, k3, k4 respectively, and in this embodiment, it is assumed that k1 < k2 < k3 < k4.

[0072] The calculation method of k1, k2, k3, k4 can be through the straight-line distance formula between two points, which is well known and will not be repeated. Those skilled in the art can also use distance sensors to detect the distance between two points or other technical means to obtain.​​​

[0073] The closer the distance between P5 and P1, P2, P3, P4 is, the greater the influence factor of the Z value of P1, P2, P3, P4 is.

[0074] Specifically, the smaller the distance ratio between P1, P2, P3, P4 and P5 is, the greater the influence factor of the Z value of P1, P2, P3, P4 is, and the greater the distance ratio between P1, P2, P3, P4 and P5 is, the smaller the influence factor of the Z value of P1, P2, P3, P4 is.

[0075] In the embodiment, the calculation formula of the influence factor q1, q2, q3, q4 of each point is:

[0076]

[0077] The product of the Z value of P1, P2, P3, P4 and the influence factor is assigned to the Z value of P5.

[0078] The product of the Z value of P1, P2, P3, P4 and the influence factor is assigned to the Z value of P5, and the Z-axis coordinates of P1, P2, P3, P4 are Z1, Z2, Z3, Z4, and the formula of the Z value of P5 is:

[0079] Z5=q1*Z1+q2*Z2+q3*Z3+q4*Z4.

[0080] In the embodiment, the pressure sensor is arranged below the hot bed. Since the mass of the hot bed is relatively stable, the change of the pressure received by the pressure sensor can be accurately fed back during the detection process, and the Z-axis coordinate of the test point can be quickly fed back. After adjusting the height value of the limit switch, the space coordinate between the plane formed by the zero return of the internal control motor of the 3D printer and the hot bed plane may change again. In addition, the global coordinate of the hot bed surface is detected again to obtain more accurate hot bed plane coordinates, and the 3D printing precision is further improved.

[0081] Embodiment 2:

[0082] The embodiment provides a 3D printer hot bed leveling method. The difference between the embodiment and embodiment 1 is that when the hot bed may be tilted and needs to be detected and leveled, the embodiment can be implemented alone. As shown in Figure 2 , the specific method is:

[0083] A space rectangular coordinate system is established with the hot bed center as the origin, the planar coordinates of the mapping points of each limit switch on the hot bed plane and the planar coordinates of the hot bed center point are obtained, and in the hot bed printing range, a reference point is selected between the mapping point of each limit switch on the hot bed plane and the hot bed center point, the planar coordinates of each reference point are obtained, and the hot bed center point and the reference points are detected to obtain the Z value coordinates of the hot bed center point and the reference points.

[0084] Specifically, as shown in Figure 4 The parallel arm type 3D printer is provided with at least three limit switches for limiting the control motor, the limit switches are respectively installed on the three columns of the 3D printer, and the limit switches are respectively column A', column B' and column C'. According to the model of the 3D printer, a space rectangular coordinate system is established with the hot bed center point O as the origin, the planar coordinates of the hot bed center point O are (0, 0), the hot bed printing radius is R, the distance between the column and the hot bed center point O is R', the coordinates of the column on the hot bed plane mapping point are column A'(0, sin90R'), column B'(sin60R', -sin30R') and column C'(-sin60R', -sin30R'), the coordinates of the limit switch mapping on the hot bed plane are limit switch mapping point A(0, sin90R'), limit switch mapping point B(sin60R', -sin30R') and limit switch mapping point C(-sin60R', -sin30R'), a reference radius r is set, wherein r

[0085] After obtaining the coordinates of the hot bed center point, the reference point and the limit switch mapping point of the 3D printer, the points on the hot bed surface are detected, that is, the hot bed center point and the reference points are detected. The detection method is the same as the detection method of the reference point a in embodiment 1.

[0086] The above process can also obtain the three-dimensional coordinates of the hot bed center point O, the reference point b, and the reference point c. The present application does not limit the number of limit switches and the number of reference points of the 3D printer. For example, the number of reference points can be increased to reference point d (sin60r, sin30r), reference point e (0, -sin90r), and reference point f (-sin60r, sin30r). According to the distance between the limit switch mapping point on the hot bed plane and the selected reference point, the influence factor of the Z value of the reference point d, the reference point e, and the reference point f on the limit switch Z axis adjustment amount is determined, and the method is the same as the Z value calculation of point P5 in Embodiment 1, thereby determining the limit switch Z axis adjustment amount.

[0087] According to the coordinate ratio of the hot bed center point to the reference point, the hot bed center point to the limit switch mapping point, the ratio of the reference point to the selected reference point according to the limit switch mapping point on the hot bed plane, and the Z value difference between the reference point and the hot bed center point, the Z axis adjustment amount of the limit switch is calculated.

[0088] According to the Z axis adjustment amount of each limit switch, the height value of the limit switch is adjusted, so that the plane formed by the control motor zero position is relatively parallel to the hot bed plane.

[0089] Wherein, the parallel arm type 3D printer is provided with a limit switch and a control motor on each column, the limit switch is used to limit the starting state position before and after the completion of printing, the control motor is connected with the parallel arm, and is used to drive the 3D printer parallel arm to complete the up-down displacement. The adjustment of the height value of the limit switch reflects the adjustment of the height of the control motor zero position. In addition, those skilled in the art should know that the names of the limit switch and the control motor in different types of 3D printers are also different, the limit switch can be replaced by the motor limit device in the 3D printer, and the control motor can be replaced by the electric device driving the printing nozzle, and under the condition of no substantial change in technical content, it is also regarded as the scope of the present application. As shown in Figure 5 When the plane formed by the control motor zero position is relatively parallel to the hot bed plane, the rough adjustment of the 3D printer hot bed is completed.

[0090] In this embodiment, the adjustment amount of the limit switch is calculated by setting the reference point, so that the plane formed by the control motor zero position is relatively parallel to the hot bed plane, thereby ensuring that the internal space of the printer is relatively positive, realizing the inclination detection and printing leveling of the hot bed, and ensuring the printing precision.

[0091] Embodiment 3:

[0092] The present embodiment provides a 3D printer hot bed leveling method, which is different from Embodiment 1 in that it can be implemented alone for the case that the hot bed surface is convex or concave or the hot bed surface is slightly inclined. As shown in Figure 3 The specific method is:

[0093] The 7*7 matrix test points are arranged on the hot bed for detection, and the 3D coordinates of the 7*7 matrix test points in the printer space are obtained by detection, and the detection method of the matrix test points is the same as the method of the reference point a described in Embodiment 1.

[0094] Specifically, for a rectangular hot bed, the 7*7 matrix test points are arranged in the printing range of the 3D printer hot bed as shown in the figure. Figure 6 In order to improve the accuracy of the detection of the global coordinates of the hot bed surface, the 7*7 matrix test points are uniformly distributed in the printing range of the 3D printer hot bed.

[0095] Specifically, for a circular hot bed, the method for processing the matrix test points is as follows:

[0096] The rectangle composed of the 7*7 matrix test points is the circumscribed rectangle of the circular hot bed.

[0097] The matrix test points beyond the printing range of the hot bed are detected as substitute points with the points closest to them in the printing range of the hot bed.

[0098] More preferably, when n>2, as shown in the figure, for a circular hot bed, the method for processing the matrix test points is as follows: Figure 7

[0099] The rectangle composed of the n*n matrix test points is the circumscribed rectangle of the circular hot bed.

[0100] The four vertices of the n*n matrix test points are removed.

[0101] The matrix test points beyond the printing range of the hot bed are detected as substitute points with the points closest to them in the printing range of the hot bed.

[0102] When n=2, for a circular hot bed, the method for processing the matrix test points is as follows:

[0103] The rectangle composed of the 2*2 matrix test points is the circumscribed rectangle of the circular hot bed.

[0104] The four matrix test points beyond the printing range of the hot bed are detected as substitute points with the points closest to them in the printing range of the hot bed.

[0105] By shrinking the matrix test points beyond the range of the circular hot bed into the printing range of the hot bed, the density of the detection points at the edge of the hot bed is enriched.

[0106] After detection, the 3D coordinates of the 7*7 matrix test points are obtained. The method for detecting the 7*7 matrix test points is as described above, and will not be repeated here.

[0107] ​The Z value of the coordinate point printed in real time on the hot bed by the 3D printer is calculated according to the distance relationship with the four matrix test points closest to the four matrix test points.

[0108] Specifically, as shown in the figure, Figure 8 the coordinate point printed in real time on the hot bed by the 3D printer is P5, the coordinates of P5 are (X5, Y5, Z5), Z5 is unknown at this time, the four matrix test points closest to P5 are P1, P2, P3 and P4 in order from near to far.

[0109] The XY coordinates of the coordinate point P5 printed in real time on the hot bed are obtained, and the four matrix test points P1, P2, P3 and P4 closest to P5 are obtained according to the XY coordinates of P5 and the distances from P5 are calculated respectively; the coordinates of P5 are (X5, Y5, Z5), the coordinates of P1 are (X1, Y1, Z1), P2 (X2, Y2, Z2), P3 (X3, Y3, Z3), and P4 (X4, Y4, Z4).

[0110] The distances from P5 to P1, P2, P3 and P4 are k1, k2, k3 and k4 respectively, and in this embodiment, k1 < k2 < k3 < k4.

[0111] The calculation method of k1, k2, k3 and k4 can be through the straight line distance formula between two points, which is well known and will not be repeated. Those skilled in the art can also use distance sensors to detect the distance between two points in the 3D printer or other technical means to obtain the distance.

[0112] The closer the distance from P5 to P1, P2, P3 and P4, the greater the influence factor of the Z value of P1, P2, P3 and P4.

[0113] Specifically, the smaller the distance ratio of P1, P2, P3 and P4 to P5, the greater the multiplication influence factor of the Z value of P1, P2, P3 and P4, and the greater the distance ratio of P1, P2, P3 and P4 to P5, the smaller the multiplication influence factor of the Z value of P1, P2, P3 and P4.

[0114] In this embodiment, the calculation formula of the influence factor q1, q2, q3 and q4 of each point is:

[0115]

[0116] The product of the Z value of P1, P2, P3 and P4 and the influence factor is assigned to the Z value of P5.

[0117] The product of the Z value of P1, P2, P3 and P4 and the influence factor is assigned to the Z value of P5, and the Z axis coordinates of P1, P2, P3 and P4 are Z1, Z2, Z3 and Z4, and the formula of the Z value of P5 is:

[0118] Z5 = q1 * Z1 + q2 * Z2 + q3 * Z3 + q4 * Z4.

[0119] The embodiment can detect small inclination of the hot bed surface and compensate the feedback of the printing nozzle according to the possible convex and concave of the hot bed surface, so that the 3D printer can lift or drop the printing nozzle in time, and the printing precision is improved. The embodiment realizes the automatic detection and compensation technology of the hot bed of the 3D printer, and improves the quality of the 3D printing product.

[0120] Embodiment 4:

[0121] As shown in Figure 9 The embodiment provides a hot bed leveling device 100 of a 3D printer, which is used for realizing the hot bed leveling method of the 3D printer as described in the embodiment 1. The hot bed leveling device 100 of the 3D printer comprises: a detection module 101 comprising a pressure sensor, which is used for feeding back a signal of a pressure value change on the hot bed; an acquisition module 102, which is used for acquiring coordinates of a limit switch and coordinates of a detection test point; a control module 103, which is used for driving a printing nozzle to detect a test point; a processing module 104, which is used for calculating a Z value of a real-time coordinate point and calculating a Z-axis adjustment amount of the limit switch according to the coordinate value of the matrix test point; and a storage module 105, which is used for storing 3D printer parameters, coordinates of the detection test point and the Z-axis adjustment amount of the limit switch.

[0122] Embodiment 5:

[0123] The embodiment discloses a computer readable storage medium, which comprises a stored computer program. When the computer program runs, the computer readable storage medium controls the device where the computer readable storage medium is located to execute the hot bed leveling method of the 3D printer of the above-mentioned embodiment. More specific examples (a non-exhaustive list) of the computer readable storage medium include an electrical connection with one or more wires, a portable computer diskette, a hard disk, a ROM, an erasable programmable read-only memory, a hard disk, a CD-ROM, a magnetic storage device, or any suitable combination of the above, or any other form of computer readable storage medium well known in the art.

[0124] Embodiment 6:

[0125] The embodiment discloses a 3D printer, including a heat bed leveling device of the 3D printer, the heat bed leveling device of the 3D printer comprising: an acquisition module for acquiring the coordinates of a limit switch and the coordinates of a detection test point; a storage module for storing the parameters of the 3D printer, the coordinates of the detection test point and the Z-axis adjustment amount of the limit switch; a control module for driving a printing nozzle to detect a test point; a detection module comprising a pressure sensor for feeding back the signal of the change of the pressure value on the heat bed; and a processing module for calculating the Z value of a real-time coordinate point and the Z-axis adjustment amount of the limit switch according to the coordinate value of a matrix test point. The 3D printer can be a parallel arm type, a gantry type and other 3D printing devices comprising a limit switch. Those skilled in the art can understand that the schematic diagram is only an example of the 3D printer and does not constitute a limitation on the 3D printer, and the 3D printer can comprise more or fewer components than the example, or some components can be combined, or different components, for example, the 3D printer can also comprise an input / output device, a network access device, a bus and the like.

Claims

1. A 3D printer hot bed leveling method, characterized in that, The application relates to a 3D printer height value detection method and device. A space rectangular coordinate system is established with a hot bed center as a starting point, plane coordinates of mapping points of each limit switch of the 3D printer on a hot bed plane and plane coordinates of the hot bed center point are obtained, a reference point is selected between the mapping points of each limit switch on the hot bed plane and the hot bed center point in a hot bed printing range, plane coordinates of each reference point are obtained, the hot bed center point and each reference point are detected, and Z value coordinates of the hot bed center point and each reference point are obtained; Z axis adjustment amounts of each limit switch are respectively calculated according to distances from the hot bed center point to the reference points, distances from the hot bed center point to the mapping points of the limit switches and Z value differences between the reference points and the hot bed center point; The height values of the limit switches are respectively adjusted according to the Z axis adjustment amounts of the limit switches, so that a plane formed by a control motor zero return position is relatively parallel to the hot bed plane; N*n matrix test points are arranged on the hot bed plane for detection, and three-dimensional coordinates of the n*n matrix test points in the 3D printer space are obtained; wherein n>=2; Z values of real-time printing coordinate points of the 3D printer on the hot bed are calculated according to distance relationships of four closest matrix test points; The Z values of the closest four matrix test points are multiplied by influence factors, and the products are assigned to the Z values of the real-time printing coordinate points.

2. The 3D printer hot bed leveling method of claim 1, wherein, The hot bed center point, the reference point and the matrix test point are to-be-detected points, and a detection method is as follows: a pressure sensor is installed under the hot bed, a printing nozzle is first moved to an XY coordinate intersection point according to plane coordinates of the to-be-detected points, and finally vertically moves downward along a Z axis direction until the printing nozzle moves to contact the hot bed plane, a pressure signal of the pressure sensor changes, the Z axis moving distance of the printing nozzle is recorded at the moment of the pressure signal change, the Z axis moving distance of the printing nozzle is converted into a Z value coordinate of the to-be-detected point, and three-dimensional coordinates of the to-be-detected point are obtained.

3. The method of claim 2, wherein the 3D printer hot bed leveling method is characterized by, When the to-be-detected points are detected, the to-be-detected points are detected at least twice, and a specific method is as follows: an allowed error range of a Z value difference of the to-be-detected points is set, a Z value of the to-be-detected point is recorded after first detection, the same to-be-detected point is detected again for second detection, a Z value difference of the to-be-detected point detected twice continuously is calculated, and it is judged whether the Z value difference of the to-be-detected point is within the error range; if the Z value difference of the to-be-detected point is within the error range, detection of the next to-be-detected point is performed; If the Z value difference of the to-be-detected point is out of the error range, detection of the to-be-detected point is continuously triggered until the Z value difference of the to-be-detected point detected twice continuously is within the error range; an average value of the Z values within the error range is taken as the Z value of the to-be-detected point.

4. The 3D printer hot bed leveling method of claim 1, wherein, The method for calculating the Z axis adjustment amount of each limit switch is as follows: Obtain the coordinates (Xo, Yo, Zo) of the center point O of the hot bed after detection, the coordinates (X I , Y I ) of the limit switch mapping point, the coordinates (X i , Y i , Z i ) of the reference point between the limit switch mapping point and the center point of the hot bed, and set the Z-axis adjustment amount of the limit switch as Z I ; The distance from the hot bed center point O to the reference point is calculated as The distance from the hot bed center point O to the limit switch mapping point is calculated as The limit switch Z-axis adjustment amount is:

5. The 3D printer hot bed leveling method of claim 1, wherein, The method for arranging the n*n matrix test points on the hot bed is as follows: The rectangle composed of the n*n matrix test points is a circumscribed rectangle of the circular hot bed; wherein n>=2; Matrix test points beyond the hot bed printing range are detected by taking points closest to the matrix test points within the hot bed printing range as substitute points.

6. The 3D printer hot bed leveling method of claim 1, wherein, The method for calculating the Z value of the real-time printing coordinate point on the hot bed of the printer is specifically: setting the real-time printing coordinate point on the hot bed as P5, and the four matrix test points closest to P5 as P1, P2, P3 and P4; The XY coordinates of the real-time printing coordinate point P5 on the hot bed are obtained, and the distances between the four matrix test points P1, P2, P3 and P4 closest to P5 and P5 are obtained according to the XY coordinates of P5; The influence factors q1, q2, q3 and q4 of the points are calculated according to the principle that the closer the distance from P5 to P1, P2, P3 and P4 is, the greater the influence factor of the Z value of P1, P2, P3 and P4 is. The product of the Z value of P1, P2, P3 and P4 and the influence factor is assigned to the Z value of P5.

7. The method of claim 6, wherein the method further comprises: The calculation method of the influence factors q1, q2, q3 and q4 of the points is: The smaller the distance ratio of P1, P2, P3 and P4 to P5 is, the greater the influence factor of the multiplication of the Z values of P1, P2, P3 and P4 is, and the greater the distance ratio of P1, P2, P3 and P4 to P5 is, the smaller the influence factor of the multiplication of the Z values of P1, P2, P3 and P4 is.

8. A heat bed leveling device of a 3D printer, characterized in that, The hot bed leveling device of the 3D printer is used to realize the hot bed leveling method of the 3D printer according to any one of claims 1-7, comprising: An acquisition module for acquiring the coordinate of the limit switch mapping point and the coordinate of the detection test point; A storage module for storing the 3D printer parameters, the coordinate of the detection test point and the limit switch Z-axis adjustment amount; A control module for driving the printing nozzle; A detection module including a pressure sensor for feeding back the signal of the pressure value change on the hot bed; A processing module for calculating the Z value of the real-time coordinate point and the limit switch Z-axis adjustment amount according to the coordinate value of the matrix test point.

9. A computer-readable storage medium, characterized in that, A computer program for storing, which makes the computer execute the hot bed leveling method of the 3D printer according to any one of claims 1-7.

10. A 3D printing device, characterized by The 3D printer hot bed leveling device of claim 8. The 3D printer hot bed leveling device of claim 8.

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