CN109334006B

CN109334006B - 3D printer-based spray head needle tip calibration method and low-temperature printing platform

Info

Publication number: CN109334006B
Application number: CN201811053129.3A
Authority: CN
Inventors: 张传杰; 袁玉宇
Original assignee: Medprin Regenerative Medical Technologies Co Ltd
Current assignee: Medprin Regenerative Medical Technologies Co Ltd
Priority date: 2018-09-10
Filing date: 2018-09-10
Publication date: 2021-07-16
Anticipated expiration: 2038-09-10
Also published as: CN109334006A

Abstract

The invention provides a 3D printer-based spray head needle tip calibration method and a low-temperature printing platform, wherein the spray head needle tip calibration method specifically comprises the following steps: s01: in the rapid positioning stage, the controller drives the spray head needle tip to approach the position sensor at a speed V2, so that the needle tip drives the calibration plane of the position sensor to generate a retraction displacement L2, and the controller calculates the initial calibration height H of the needle tip and the calibration plane of the position sensor according to the retraction displacement L2; s02: returning to the secondary calibration height stage, the controller drives the nozzle needle tip to move reversely by a distance of L2+ L3 at a speed of V3, wherein H > L3> 0; s03: in the slow calibration stage, the controller drives the needle tip to move towards the calibration plane at a speed V4, so that the needle tip drives the calibration plane of the position sensor to generate a retraction displacement L4, and the calibration process is completed. Through the scheme, the spray head needle point can be calibrated more quickly and efficiently.

Description

3D printer-based spray head needle tip calibration method and low-temperature printing platform

Technical Field

The invention relates to the technical field of 3D printing, in particular to a 3D printer-based spray head needle tip calibration method and a low-temperature printing platform.

Background

From the analysis of printing and forming principles, 3D printing is a process of transferring material or energy in the form of extrusion, jetting or emission to a forming platform according to a predetermined trajectory through a plurality of specific nozzles, and finally obtaining a three-dimensional model through layer-by-layer accumulation.

For extrusion type 3D printing equipment, in order to realize more efficient printing operation, the trend of necessarily developing when improving the automation level and the accuracy of equipment, on common biological 3D printing equipment, the automatic calibration of the needle point is an important index for measuring the performance of the equipment, and the equipment with the needle point calibration function can ensure that the position of the needle point is controllable when different spray heads are switched with each other in printing and the position of the needle point is calibrated again after the needle head is replaced, so that manual intervention operation can be effectively reduced, and the printing accuracy is improved. However, when a general needle tip is calibrated, in order to improve the accuracy of a calibration result, a nozzle often needs to slowly touch a sensor to acquire a position parameter, but since an initial calibration stroke is long, the time consumption of a calibration process is often high, and thus the printing efficiency is affected. Besides the problem of needle point calibration efficiency, after the first time of loading materials by the spray head, the problem that no materials are extruded out from the needle point after the spray head enters the model track to move is often caused due to the uncontrollable pre-extrusion printing process.

Disclosure of Invention

The invention provides a 3D printer-based spray head needle point calibration method and a low-temperature printing platform, aiming at overcoming at least one defect of the prior art, and the method can realize the spray head needle point calibration which is faster and more efficient.

In order to solve the technical problems, the technical scheme of the invention is as follows: A3D printer-based spray head needle point calibration method specifically comprises the following steps:

s01: in the rapid positioning stage, the controller drives the spray head needle tip to approach the position sensor at a speed V2, so that the needle tip drives the calibration plane of the position sensor to generate a retraction displacement L2, and the controller calculates the initial calibration height H of the needle tip and the calibration plane of the position sensor according to the retraction displacement L2;

s02: returning to the second calibration height stage, the controller drives the spray head needle tip to move in a reverse direction at a speed V3 for a distance of L2+ L3, wherein H > L3>0, and the needle tip is separated from the calibration plane of the position sensor and reaches the second calibration height;

s03: in the slow calibration stage, the controller drives the needle tip to move towards a calibration plane at a speed V4, wherein V2 is greater than V4, so that the needle tip drives the calibration plane of the position sensor to generate a retraction displacement L4, and the calibration process is completed.

The principle of using a position sensor for position calibration is: the needle point keeps vertical and slowly approaches to a calibration plane of the position sensor, when the needle point contacts the calibration plane of the position sensor and causes the calibration plane to generate certain displacement, the position sensor immediately outputs an electric signal equivalent to the displacement, and the electric signal sent by the position sensor is collected and subjected to operation processing to be converted into the position of the needle point at the moment.

In a conventional spray head needle tip position calibration system, the position of the needle tip before calibration is started is generally far away from a calibration plane and the spatial position is unknown, and the needle tip moves towards the calibration plane at a certain speed when calibration is started and enables the calibration plane to generate signal feedback. In the process, the initial position of the needle tip is unknown, so that the speed of the needle tip moving to the calibration plane is difficult to evaluate, if the calibration time is shortened, the speed needs to be increased, but the accuracy of calibration is reduced when the speed is pursued; if the speed is reduced in order to improve the alignment accuracy, the time required for tip alignment is inevitably greatly increased by reducing the speed when the tip is at a large distance from the alignment surface, and the printing efficiency is reduced.

In order to shorten the calibration time and improve the calibration precision, the invention provides the method for calibrating the nozzle tip of the 3D printer, during calibration, the tip moves to the calibration plane of the position sensor at a faster speed V2, the calibration plane is pushed to move in the rated stroke of the position sensor after contacting with the calibration plane until the position sensor has position signal feedback output, the controller preliminarily calculates the initial calibration height H of the tip relative to the calibration plane of the position sensor according to the position signal, namely the basic position of the tip, then the controller drives the tip to keep a higher speed V3 to raise L2+ L3(H > L3>0) reversely, so that the tip is separated from the calibration plane to the second calibration tip height, at the moment, although the tip is separated from the calibration plane, the position of the tip is very close to and controllable, and the controller drives the tip to move to the calibration plane of the position sensor again at a slower speed V4 until the position sensor outputs an accurate position signal, in the scheme, the calibration plane of the sensor movement mechanism and the molding plane of the low-temperature printing platform are in the same horizontal plane or the quantitative known relative horizontal height difference is kept, so that the controller can determine that the needle point and the molding plane of the low-temperature printing platform are in a proper printing distance by reversely moving the needle point after obtaining an accurate position signal of the needle point. Therefore, the method for calibrating the needle point by adopting the double-touch type can better ensure the calibration precision and shorten the calibration time.

Preferably, the contact force range of the position sensor is 1N-5N, and preferably, the contact force range of the position sensor is 1N-3N.

Preferably, the forming size of the 3D printer in the Z-axis direction in the scheme is 5 mm-500 mm, and more preferably, the forming size of the 3D printer in the Z-axis direction is 10 mm-200 mm. Because this scheme can fix a position fast, consequently, to the 3D printer of the shaping size of Z axle direction in tens or even hundreds of millimeters within ranges, adopt the method of twice touch's needle point calibration in this application can guarantee calibration accuracy more and shorten calibration time.

Preferably, the effective operating speed range of the position sensor is 50-200 mm/min.

Specifically, the maximum value of L2 and L4 is the rated travel of the position sensor, V3 is larger than or equal to V2, and V4 is the effective operating speed of the position sensor.

Preferably, the first and second liquid crystal materials are,

wherein L is_maxIs the rated travel of the position sensor, F is the contact force of the position sensor, and m is the mass of the nozzle and the needle tip. V2 satisfying this condition ensures that damage to the sensor does not occur when the needle tip moves too quickly.

Preferably, the contact force of the position sensor is 1N, the weight of the moving part of the spray head is 5kg, the limit value of L2 is 5mm, and the actual initial distance χ of the needle tip from the calibration plane of the position sensor during initial calibration is more than or equal to 6.650 mm.

Preferably, the contact force of the position sensor is 1.5N, the weight of the moving part of the spray head is 5kg, the limit value of L2 is 5mm, and the actual initial distance χ of the needle tip from the calibration plane of the position sensor during initial calibration is more than or equal to 6.188 mm.

Preferably, the contact force of the position sensor is 2.5N, the weight of the moving part of the spray head is 5kg, the limit value of L2 is 5mm, and the actual initial distance χ of the needle tip from the calibration plane of the position sensor during initial calibration is more than or equal to 5.995 mm.

Preferably, the contact force of the position sensor is 3N, the weight of the moving part of the spray head is 5kg, the limit value of L2 is 5mm, and the actual initial distance χ of the needle tip from the calibration plane of the position sensor during initial calibration is more than or equal to 5.910 mm.

Before step S01 begins, the calibration plane of the position sensor may be adjusted to be at the same level or some known distance from the low temperature print zone shaping plane. Such adjustment ensures that the distance of the needle tip relative to the low temperature print zone is accurate after calibration.

The invention also provides a low-temperature printing platform of the 3D printer, which can realize the calibration process of the nozzle tip before printing, and specifically comprises a low-temperature printing area and a position sensor arranged on one side of the low-temperature printing area, wherein the position sensor comprises a sensor movement mechanism and a sensor communication interface, the surface of the sensor movement mechanism is a calibration plane of the position sensor, and the position sensor feeds back position parameters to the controller through the sensor communication interface.

Further, the low-temperature printing platform comprises a fine adjustment platform, and the fine adjustment platform can adjust the distance between the low-temperature printing area forming plane and the calibration plane of the position sensor. The fine adjustment platform mainly ensures that the low-temperature printing area and the calibration plane of the position sensor are on the same plane or have a known distance before the needle point position is calibrated, so that the needle point position after calibration can be ensured to be continuously kept accurate. In particular, the fine tuning platform may be automated or manual.

Further, the fine setting platform includes fine motion platform moving mechanism, locking knob and fine setting knob, position sensor with fine motion platform moving mechanism fixed, the locking knob can lock fine motion platform moving mechanism's current height, the fine setting knob can be adjusted fine motion platform moving mechanism's height under the state that the locking knob unclamped. Therefore, the position of the position sensor can be moved by manually adjusting the fine adjustment knob and the locking knob.

Furthermore, this low temperature print platform still includes blanking detection module and blanking and accomodates the module, blanking detection module is used for detecting whether there is the material to extrude, blanking accomodate the module setting and be used for accomodating the material that drips in blanking detection module's below.

Preferably, the blanking detection module comprises an optical sensor, and the blanking storage module is arranged below the optical sensor of the blanking detection module and can store the dropped blanking. The spray head which finishes the pre-extrusion operation receives the instruction of the controller to stop the material extrusion, but due to the reasons of material viscosity and the like, part of the extruded material is accumulated around the tip of the nozzle to form a slobbering phenomenon, and when the slobbering is serious, the whole mass of the material can drop to damage the model structure. It is therefore necessary to wipe excess material off the tip of the nozzle after the pre-extrusion operation is complete.

Further, the blanking storage module comprises a storage box main body, a magnetic suction device and a storage box clamping groove, the storage box main body is located at the position below the transmitting end and the receiving end, the storage box clamping groove can limit the position of the storage box main body, and the magnetic suction device is located in the storage box clamping groove and can attract and fix the storage box main body in the storage box clamping groove. The preferred setting of receiver draw-in groove is on the board, and magnetism is inhaled and can only be set up in the receiver draw-in groove, also can both set up in the receiver draw-in groove and set up in the receiver main part that corresponds the position to can realize making things convenient for the fixed of receiver main part and dismantle.

Furthermore, the low-temperature printing platform further comprises a needle point wiping area, the wiping area comprises a brush, and the needle point of the spray head can do reciprocating motion in the needle point wiping area, so that redundant materials of the needle point of the spray head can be cleaned.

Further, the brush and the storage box main body are fixed or the brush and the storage box main body are integrated. Such design just can take out the receiver and change receiver or clearance blanking when the blanking gradually full in the receiver.

Compared with the prior art, the beneficial effects are:

(1) in the process of calibrating the nozzle needle tip, the position sensor is touched twice at two speeds, the needle tip is far away from the position sensor when the needle tip is touched for the first time, the calibration time can be effectively shortened by touching at a higher speed, the needle tip is near to the sensor when the needle tip is touched for the second time, and more reaction time can be reserved for the position sensor when the needle tip is touched at a lower speed, so that the accuracy of needle tip calibration is improved;

(2) the relative horizontal position of the calibration plane of the position sensor and the molding plane of the low-temperature printing platform can be adjusted, and after the levelness of the printing platform is adjusted, the calibration plane of the position sensor and the molding plane of the low-temperature printing platform can be kept at the same horizontal plane or have a known distance difference by adjusting the micro-motion knob;

(3) the nozzle blanking detection module can help to detect whether the material in the nozzle charging barrel reaches the needle point position before printing starts, the coordination between the nozzle material extruding action and the nozzle movement track can be effectively improved through the blanking detection function, and the phenomenon that the needle point does not extrude the material after the nozzle enters the model track movement is avoided;

(4) by arranging the blanking storage box, extruded materials can be recovered during blanking detection, and the materials are prevented from fouling sensors of the printing platform and the blanking detection system; the blanking storage box can be stably fixed and quickly dismounted by adopting the form of fixing the blanking storage box by magnetic attraction, so that the efficiency is greatly improved;

(5) through setting up the needle point and wiping the functional area, wipe the needle point after the blanking detects, avoided the hydrostomia phenomenon of needle point, avoided the hydrostomia material to take place to gather the drippage and cause the model to destroy at the printing in-process simultaneously when having reduced the syringe needle jam possibility.

Drawings

FIG. 1 is a flow chart of a two touch tip calibration in an embodiment of the invention.

FIG. 2 is a flow chart of a conventional single touch tip calibration in accordance with an embodiment of the present invention.

FIG. 3 is a schematic diagram of a conventional single touch tip calibration in accordance with an embodiment of the present invention.

FIG. 4 is a schematic diagram of a two touch tip calibration in accordance with an embodiment of the present invention.

FIG. 5 is a calibration time trace plot of two tip calibration methods in an embodiment of the present invention.

Fig. 6 is a perspective view of a low-temperature printing platform of the 3D printer in the embodiment of the invention.

FIG. 7 is a schematic diagram of a tip calibration module and a blank detection module according to an embodiment of the invention.

Fig. 8 is a schematic structural view of the blanking storage box in the embodiment of the invention.

Fig. 9 is an exploded view of a cryogenic printing platform configuration with two stages of flow channels in an embodiment of the present invention.

FIG. 10 is a schematic diagram of a two-stage flow channel structure of a thermal plate in a low-temperature printing platform according to an embodiment of the invention.

In the figure: the system comprises a low-temperature printing area 1, a platform substrate 1001, a hot plate sealing cover 1002, a water inlet 1003, a water outlet 1005, a platform hot plate 1004, a semiconductor refrigerating sheet group 1006, a low-temperature plate 1007, a temperature sensor mounting hole 1008, a primary flow channel 1009 and a secondary flow channel 1010; fine setting platform 2, fine setting knob 21, locking knob 22, fine motion platform moving mechanism 23, position sensor 3, calibration plane 3001, sensor communication interface 3002, blanking storage module 4, receiver main part 41, magnetism 42, receiver draw-in groove 43, the district 5 is wiped to the needle point, blanking detection module 6, transmitting terminal 601, receiving terminal 602, fixed bolster 603.

Detailed Description

The drawings are for illustrative purposes only and are not to be construed as limiting the patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent.

The first embodiment is as follows:

referring to fig. 1-5, the a sensor is used to calibrate the tip position of the nozzle with a conventional one-touch method and a two-touch method according to the present application, the actual initial distance between the tip and the calibration plane of the position sensor at the initial calibration is set to χ, and the technical parameters of the a sensor are shown in table 1:

rated stroke	5mm
		Repeatability	1um
Effective speed of operation	The operation speed is 50-200 mm/min
		Contact life	300 ten thousand times
Protection structure	IP67
		Contact force	1.5N
Contact site material	Super hard alloy

TABLE 1

A conventional flow of calibrating the position of the nozzle tip by one touch is shown in fig. 2, and the calibration principle is shown in fig. 3, where the distance from the nozzle tip to the stop of the movement of the nozzle tip after touching the calibration plane of the position sensor 1 at the speed V1 is L1(L1 is not more than 5 mm), and the time taken for calibrating the nozzle tip by one touch is τ (χ + L1)/V1;

the process of calibrating the nozzle tip by adopting the two-touch method in the application is shown in fig. 1, and the nozzle tip moves to the calibration plane of the position sensor 1 at the speed V2, so that the distance from the tip to the stop along with the movement of the tip after touching the calibration plane of the position sensor 1 is L2(L2 is less than or equal to 5 mm), and at this time, the controller drives the tip to move reversely at the speed V3 to raise the tip by the distance of L2+ L3 so as to ensure that the tip is separated from the calibration plane. At this time, the needle tip reaches the second calibration height, then the controller drives the needle tip to move to the calibration plane of the position sensor 1 at the speed V4, and the distance from the movement of the needle tip to the stop after touching the calibration plane is L4(L2 is less than or equal to 5 mm), so that the time spent in calibrating the nozzle needle tip by adopting the two-touch method is T ═ chi + L2)/V2+ (L2+ L3)/V3+ (L3+ L4)/V4.

When two-tap calibration is used, the purpose of the first tap is to allow the controller of the 3D printer to obtain an initial calibrated height H of the stylus tip relative to the calibration plane of the position sensor, i.e. the base position of the stylus tip, regardless of the accuracy of the position, so that a greater movement velocity V2 can be selected at the time of the first tap. When touching the calibration plane at the speed of V2, we need to ensure that the needle tip can stop within the rated travel of the position sensor, and the contact force F and the rated travel L of the position sensor can be known from the table 1_maxWhen the weight m of the needle tip and the moving member of the head is set, the relationship between the acceleration of the needle tip and the contact velocity is 0-V2 according to Newton's second law F ═ m × a²2aL and L ≦ L_maxIs obtained by

The contact force F of the sensor substituted into A is 1.5N, and the rated stroke L is_maxAnd 5mm, selecting the weight m of the needle tip and the moving part of the spray head as 5kg, and calculating according to the formula to obtain the maximum value V2 of 55mm/s, wherein the maximum value V2 is not more than 55mm/s, namely the sensor is guaranteed not to be damaged by needle tip overshoot, and the limiting speed of the needle tip movement does not exceed 55 mm/s. In this embodiment, to ensure that needle tip overshoot does not occur and damage the sensor, we take V2 to be 50mm/s for safety.

Meanwhile, according to the effective operation speed of 50-200 mm/min for ensuring the calibration accuracy given in table 1, that is, the minimum effective operation speed of V1 and V4 is 50mm/min, and the maximum effective operation speed is 200mm/min, in this embodiment, to improve the calibration efficiency, V1 is selected as V4 as 200 mm/min. In addition, in order to improve the calibration efficiency, in the present embodiment, V3-V2-50 mm/s is selected.

And selecting an L1-L2-L4-5 mm within the rated stroke of the sensor, and selecting an L3 larger than zero to ensure that the needle tip is completely separated from the calibration plane during reverse lifting, wherein in the embodiment, the L3 is selected to be 5 mm. Corresponding parametersThe time formula of the calibration is substituted into (χ + L1)/V1 and T ═ χ + L2)/V2+ (L2+ L3)/V3+ (L3+ L4)/V4, and graphs of the actual initial distance χ and the time τ of the calibration and the actual initial distance χ and the time T of the calibration are drawn under the premise of ensuring the calibration accuracy in the two calibration modes, as shown in fig. 5. As shown in FIG. 5, the calibration time spent in the two calibration modes intersect at M point, and the actual initial distance corresponding to the M point is x_M6.188, when the actual initial distance χ>6.188, when T is smaller than τ, that is, when χ exceeds 6.188mm, the calibration time of the tip can be effectively shortened by using the two-touch calibration compared with the conventional one-touch calibration, thereby improving the calibration efficiency without affecting the calibration accuracy.

Because the Z-direction forming size of the 3D printer is generally dozens of even hundreds of millimeters and far exceeds 6.188mm, the calibration precision can be better ensured and the calibration time can be shortened by adopting the method of twice touch type needle point calibration. Preferably, the forming size of the 3D printer in the Z-axis direction in the embodiment is 5mm to 500mm, and more preferably, the forming size of the 3D printer in the Z-axis direction is 10mm to 200 mm.

Further, in the above calculation, we substitute V3 ═ V2 for the calculation and make the curve of fig. 5, and in fact, when V3> V2, the constant term value of the T expression of the time spent for calibration is reduced, so that the finally obtained χ is smaller than 6.188mm, i.e. when using two-touch tip calibrations, based on the parameters of the a sensor, in the range of V3 ≧ V2, as the value of V3 is continuously increased, the χ value is gradually decreased linearly, that is, there is a value of V3, so that when χ >0, the calibration time using two-touch calibration is better than that of conventional one-touch calibration, in other words, V3 is fast enough to ensure that, no matter what the value of the actual initial position χ of the tip is, the calibration time using two-touch calibration is certainly better than that of one-touch calibration.

Example two:

the sensor B is used for respectively calibrating the needle point position of the spray head by using a conventional one-touch mode and a two-touch mode, the actual initial distance between the needle point and the calibration plane of the position sensor is set to be x when the calibration is initial, and the technical parameters of the sensor B are shown in the table 2:

TABLE 2

The verification principle adopted in the embodiment is the same as that of the first embodiment, and the calculation is substituted to obtain that the limit speed of V2 is 70.7mm/s, the V3 is equal to or larger than the V2 range, and V2-V3-70 mm/s are substituted for calculation, so that x can be obtained_M5.995mm, i.e. when the actual initial distance χ>5.995mm, compared with conventional one-touch calibration, the calibration method using two-touch calibration can effectively shorten the calibration time of the needle tip, improve the calibration efficiency and not affect the calibration precision. Similarly, in the range of V3 ≧ V2, as the value of V3 is increasing, the value of χ will gradually decrease linearly.

Example three:

the C sensor is used for respectively calibrating the needle point position of the spray head by using a conventional one-touch mode and a two-touch mode, the actual initial distance between the needle point and the calibration plane of the position sensor is set to be x when the calibration is initial, and the technical parameters of the C sensor are shown in a table 3:

rated stroke	5mm
		Repeatability	0.5um
Effective speed of operation	50～200mm/min
		Contact life	300 ten thousand times
Protection structure	IP67
		Contact force	3N
Contact site material	Super hard alloy

TABLE 3

The verification principle adopted in the embodiment is the same as that of the first embodiment and the second embodiment, and the calculation is substituted to obtain that the limit speed of V2 is 77.5mm/s, the V3 is equal to or larger than the V2 range, and V2-V3-77 mm/s are substituted for calculation, so that x can be obtained_M5.910mm, i.e. when the actual initial distance χ>5.910mm, compared with conventional one-touch calibration, the calibration method using two-touch calibration can effectively shorten the calibration time of the needle tip, improve the calibration efficiency and not affect the calibration precision. Similarly, in the range of V3 ≧ V2, as the value of V3 is increasing, the value of χ will gradually decrease linearly.

Example four:

the method comprises the following steps of using a D sensor to calibrate the needle point position of the spray head by using a conventional one-touch mode and a two-touch mode of the application respectively, setting the actual initial distance between the needle point and the calibration plane of the position sensor to be x when the calibration is initial, and setting the technical parameters of the D sensor to be as shown in a table 4:

rated stroke	5mm
		Repeatability	1um
Effective speed of operation	50～200mm/min
		Contact life	300 ten thousand times
Protection structure	IP67
		Contact force	1N
Contact site material	Super hard alloy

TABLE 4

The verification principle adopted by the embodiment is the same as that of the first, second and third embodiments, and the calculation results show that the limit speed of V2 is 44.7mm/s, the same calculation result is substituted by the same method that V3 is not less than V2, V2 is not less than V3 and is not less than 44mm/s, and x can be obtained_M6.650mm, that is, when χ exceeds 6.650mm, the calibration time of the tip can be effectively shortened by using the two-touch calibration compared with the conventional one-touch calibration, thereby improving the calibration efficiency without affecting the calibration accuracy. Similarly, in the range of V3 ≧ V2, as the value of V3 is increasing, the value of χ will gradually decrease linearly.

According to the first to fourth embodiments, the mean square root>x_MIn the process, compared with the conventional one-touch calibration, the calibration method adopting the two-touch calibration can effectively shorten the calibration time of the needle point, and in a certain effective operating speed range, the larger the contact force F of the position sensor is, the larger the limit speed V2 is and the larger the limit speed x is_MValue of (A)The smaller, i.e. the larger the range of the actual initial distance χ. This means that as the position sensor contact force F increases, the effect of shortening the tip calibration time using a two touch calibration is more pronounced than using a conventional one touch calibration.

Example five:

fig. 6 is a perspective view of a low-temperature printing platform of a 3D printer in this embodiment, and the low-temperature printing platform can realize a calibration process for a nozzle needle tip before printing, and includes a platform substrate 1001 and a low-temperature printing area 1 located on the platform substrate 1001, the position sensor 3 is located on one side of the low-temperature printing area, the position sensor 3 includes a sensor movement mechanism 3001 and a sensor communication interface 3002, a surface of the sensor movement mechanism 3001 is a calibration plane of the position sensor 3, and a surface of the low-temperature printing area 1 is a molding plane of the low-temperature printing platform. The sensor motion mechanism 3001 can be telescopic motion along the needle point direction of motion, when receiving the needle point extrusion, can downstream in order to drive calibration plane downstream, can set up elastic element in the below of sensor motion mechanism 3001 to make the needle point reverse motion back, sensor motion mechanism 3001 can drive calibration plane recovery original position under the spring action. The surface of the sensor motion mechanism 3001 and the molding plane of the low-temperature printing area 1 are located on the same horizontal plane or at a known distance, and the position sensor 3 feeds back position parameters to the controller through the sensor communication interface 3002. The controller can control the movement of the needle tip according to the signal fed back by the position sensor 3.

Specifically, when the needle tip contacts the calibration plane of the position sensor and causes the calibration plane to generate a certain displacement, the position sensor immediately outputs an electrical signal equivalent to the displacement, and the controller performs operation processing according to the electrical signal sent by the position sensor and then converts the electrical signal into the position of the needle tip at the moment.

Example six:

the rest of this embodiment is the same as the fifth embodiment, and further, as shown in fig. 7, the low temperature printing platform includes a fine tuning platform 2 disposed on a platform substrate 1001, and the fine tuning platform 2 can adjust the distance between the low temperature printing area 1 and the calibration plane of the position sensor 3. Specifically, fine tuning platform 2 includes fine tuning platform moving mechanism 23, locking knob 22 and fine tuning knob 21, and position sensor 3 is fixed with fine tuning platform moving mechanism 23, and locking knob 22 can lock the current height of fine tuning platform moving mechanism 23, and fine tuning knob 21 can adjust fine tuning platform moving mechanism 23's height under the state that locking knob 22 unclamped.

When the device is used for measuring the position of the needle point, the calibration plane based on the position sensor 3 and the molding plane of the low-temperature printing area 1 are in the same horizontal plane or have known distance. However, in actual operation, due to the assembling or leveling operation of the printing platform, there may be a distance variation between the calibration plane of the position sensor 3 and the molding plane of the low temperature printing area 1, in this embodiment, the fine adjustment knob 21 is manually rotated, the height of the fine movement platform moving mechanism 23 is adjusted within a certain range by using the elastic force of the spring so as to drive the position sensor 3 fixed on the fine movement platform moving mechanism 23 to move, when the adjustment position sensor 3 and the molding plane of the low temperature printing area 1 are in the same horizontal plane, the current position can be maintained by locking the locking knob 22, so as to ensure that the distance between the needle tip and the calibration plane of the position sensor 3 represents the distance between the needle tip and the molding plane of the low temperature printing platform at the beginning of printing.

Example seven:

the other parts of this embodiment are the same as those of the fifth and sixth embodiments, as shown in fig. 7 to 8, the low-temperature printing platform further includes a blanking detection module 6, the blanking detection module 6 includes an optical sensor, the optical sensor includes an emitting end 601 and a receiving end 602, a light path can be formed between the emitting end 601 and the receiving end 602, and the controller can determine whether a printing material is extruded according to a signal of the light path that is open.

The low-temperature printing platform can further comprise a blanking storage module 4, wherein the blanking storage module 4 is arranged below the optical sensor of the blanking detection module 6 and can store the dropped blanking.

The blanking storage module 4 includes a storage box main body 41, a magnet 42 and a storage box clamping groove 43, the storage box main body 41 is located below the transmitting end 601 and the receiving end 602, the storage box clamping groove 43 can limit the position of the storage box main body 41, and the magnet 42 is located in the storage box clamping groove 43 and can attract and fix the storage box main body 41 in the storage box clamping groove 43.

The low-temperature printing platform also can comprise a needle point wiping area 5, wherein the needle point wiping area 5 comprises a brush, and the needle point of the spray head can do reciprocating motion in the needle point wiping area 5, so that redundant materials of the needle point of the spray head can be cleaned. When the nozzle after finishing the blanking detection moves to the needle point wiping area 5 together with the needle under the driving of the moving platform and reciprocates in the area until the needle point is wiped completely, the brush is fixed with the storage box main body 41. The brush needs to be a brush with proper hardness and concentration.

In an embodiment of the invention, the position sensor 3, the blanking detection module 6, the blanking storage module 4 and the needle point wiping area 5 are all located at the same side of the low-temperature printing area 1, so that the blanking detection and the cleaning of the needle point redundant materials are conveniently carried out after the needle point calibration is completed.

Example eight:

fig. 9 to 10 are structural diagrams of a low-temperature printing area 1 in this embodiment, a specific structure of the low-temperature printing area 1 includes a low-temperature board 1007 and a temperature sensor mounting hole 1008 located on a side surface of the low-temperature board 1007, a bottom surface of the low-temperature board 1007 is attached to a default cold end of a semiconductor refrigeration sheet group 1006 and coated with a heat conductive silicone grease, and a hot end of the refrigeration sheet group 1006 is attached to a platform hot plate 1004 and coated with a heat conductive silicone grease. The platform hot plate 1004 comprises a primary flow channel structure 1009 and a secondary flow channel structure 1010, wherein the primary flow channel structure 1009 is used for constraining the hot end area of the cooling liquid flowing through all the refrigeration sheets uniformly according to a certain flow direction, and the secondary flow channel structure 1010 is positioned in the primary flow channel structure and plays a role in increasing the hot contact area and preventing heat exchange dead angles. The beginning and end of the primary flow channel 1009 are respectively provided with a water inlet 1003 and a water outlet 1005 of a platform hot plate 1004 for ensuring the circulation of the cooling liquid in the flow channel. In order to prevent the heat of the coolant from being transferred to the platen base 1001 and to seal the flow channel, the platen hot plate 1004 is sealed and insulated at the lower portion thereof by a hot plate sealing cover 1002. in this embodiment, the low temperature plate 1007 and the platen hot plate 1004 are preferably made of a metal material, and the hot plate sealing cover 1002 is preferably made of a plastic material having a good heat insulating property.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A spray head needle point calibration method based on a 3D printer is characterized by specifically comprising the following steps:

2. The method for calibrating the nozzle tip of a 3D printer according to claim 1, wherein the contact force of the position sensor ranges from 1N to 5N.

3. The method for calibrating a nozzle tip of a 3D printer according to claim 1, wherein the contact force of the position sensor ranges from 1N to 3N.

4. The method for calibrating the nozzle needle point of the 3D printer according to any one of claims 2 or 3, wherein the forming size of the 3D printer in the Z-axis direction is 5 mm-500 mm.

5. The method for calibrating the nozzle needle point of the 3D printer according to any one of claims 2 or 3, wherein the forming size of the 3D printer in the Z-axis direction is 10 mm-200 mm.

6. The method for calibrating the nozzle tip of a 3D printer according to claim 4, wherein the effective operating speed range of the position sensor is 50-200 mm/min.

7. The method for calibrating the nozzle needle point of the 3D printer according to claim 6, wherein the maximum value of L2 and L4 is the rated travel of the position sensor, V3 is greater than or equal to V2, and V4 is the effective operating speed of the position sensor.

8. The method of calibrating a nozzle tip of a 3D printer according to claim 1,

wherein L is_maxIs the rated travel of the position sensor, F is the contact force of the position sensor, and m is the mass of the nozzle and the needle tip.

9. The method for calibrating the nozzle tip of a 3D printer according to claim 1, wherein: step S01 begins by adjusting the calibration plane of the position sensor to be at the same level or a known distance from the molding plane of the low temperature print zone.

10. The utility model provides a low temperature print platform of 3D printer which characterized in that: the method for realizing the nozzle tip calibration method of claim 1; including low temperature printing region (1), fine setting platform (2) and locating the position sensor (3) of one side on the low temperature printing region (1) horizontal direction, fine setting platform (2) can adjust the distance of the calibration plane of low temperature printing region (1) shaping plane and position sensor (3), position sensor (3) including sensor motion (3001) and sensor communication interface (3002), the surface of sensor motion (3001) is the calibration plane of position sensor (3), position sensor (3) are through sensor communication interface (3002) to controller feedback position parameter.

11. The cryogenic printing platform of a 3D printer according to claim 10, wherein: fine setting platform (2) including fine motion platform moving mechanism (23), locking knob (22) and fine setting knob (21), position sensor (3) with fine motion platform moving mechanism (23) fixed, locking knob (22) can lock the current height of fine motion platform moving mechanism (23), fine setting knob (21) can be adjusted the height of fine motion platform moving mechanism (23) under the state that locking knob (22) unclamped.

12. The cryogenic printing platform of a 3D printer according to claim 10, wherein: the low-temperature printing platform further comprises a blanking detection module (6) and a blanking storage module (4), wherein the blanking detection module (6) is used for detecting whether materials are extruded or not, and the blanking storage module (4) is arranged below the blanking detection module (6) and used for storing the dripped materials.

13. The cryogenic printing platform of a 3D printer according to claim 12, wherein: the low-temperature printing platform further comprises a needle point wiping area, and the needle point of the spray head can reciprocate in the needle point wiping area, so that redundant materials of the needle point of the spray head are cleaned.