CN105172153B - A kind of 3D printer hott bed balance regulator and adjusting method - Google Patents

Abstract

The invention relates to the technical field of 3D printing, in particular to a balance adjustment device and an adjustment method for a hot bed of a 3D printer. The upper surface of the hot bed is provided with more than three positioning points, and at least three of the positioning points are not on the same straight line; including a host computer that controls the extrusion nozzle of the 3D printer to move to a designated position; receives the position information of the extrusion nozzle and the hot bed Position information of the positioning point, and control the micro-controller of the heating bed positioning point to rise or fall to the specified position; the limit switch set at the heating bed positioning point; the limit switch is close to the specified distance with the extrusion nozzle When the contact point is within or fully contacted, the positioning point position information is sent to the microcontroller. Compared with the existing manual adjustment method, the present invention adopts a micro-control method to automatically complete the correction of the balance between the heated bed of the 3D printer base and the movement path plane of the extrusion nozzle. It has the advantages of fast speed, high precision and simple operation.

Description

A 3D printer hot bed balance adjustment device and adjustment method

technical field

The invention relates to the technical field of 3D printing, in particular to a balance adjustment device and an adjustment method for a hot bed of a 3D printer.

Background technique

3D printing technology has attracted more and more attention, and is widely used in processing and manufacturing, aerospace, medical repair, education and scientific research and other fields. The current 3D printing drive motor adopts the subdivision drive method to greatly improve the printing resolution. The step angle of the stepping motor is no longer the main factor affecting the accuracy of 3D printing products. At present, 3D printing is what really restricts the accuracy of 3D printing. The mechanical basic deviation of the frame of the equipment itself, because 3D printers mostly use a splicing structure, even after a precisely calibrated 3D printing equipment has been running for a period of time, the mechanical structure will have different degrees of deviation, especially the heat bed and extrusion of the 3D printer base. The deviation of the balance degree between the nozzle movement path planes will seriously affect the accuracy of 3D printing.

The commonly used solution at present is to manually correct the mechanical deviation between the 3D printer hot bed and the extrusion nozzle movement path plane before each printing. For example, the existing calibration method is to control the printing nozzle through the 3D printing host computer control software. Run to the top of the four corners of the base heating bed (taking the surface of the heating bed as a rectangle as an example), select a positioning point for each of the four corners, and manually adjust the claw nut here to fix the positioning point at each corner. Complete the correction of the height of this point, and ensure the balance between the hot bed of the 3D printer base and the movement path plane of the extrusion nozzle by keeping the four positioning points at the four corners consistent with the distance from the printing nozzle. However, the minimum thickness of each layer of the current 3D printing technology can reach 0.02mm. Even for the printing accuracy of 0.3mm, it is far beyond the range that the human eye can detect. Therefore, the existing method of using the human eye to measure the leveling cannot effectively solve the problem. The balance problem between the hot bed surface of the 3D printer base and the extrusion nozzle.

Contents of the invention

The purpose of the present invention is to overcome the problem that the 3D printer hot bed needs to be manually corrected for balance in the prior art, so that the target accuracy cannot be achieved, and to provide a method that uses a microcontroller combined with a limit switch set at the positioning point to perform all the adjustments. A 3D printer hot bed balance adjustment device for correcting the hot bed balance degree.

In the 3D printer heat bed balance adjustment device, more than three positioning points are arranged on the surface of the heat bed, and at least three of the positioning points are not on the same straight line; including,

The upper computer controls the movement of the 3D printer extrusion nozzle to the designated position;

The microcontroller receives the position information of the extrusion nozzle and the position information of the hot bed positioning point, and controls the heating bed positioning point to rise or fall to the specified position;

The limit switch is set at the positioning point of the hot bed; when the limit switch is within a specified distance or in full contact with the extrusion nozzle, it will send position information of the positioning point to the microcontroller.

As is well known, the up and down motion of the fixed point of the heated bed needs to be provided with a power device and a transmission device under the position of the fixed point of the heated bed or near the fixed point, and the power device can receive commands from the microcontroller to drive the heated bed The anchor point is raised or lowered.

The upper computer controls the movement of the extrusion nozzle by loading the G-code file, and controls the position of the extrusion nozzle by simulating the printing process. The coordinate information of the hot bed positioning point is recorded in the G-code file , so that the upper computer can directly control the movement of the extrusion nozzle to above the positioning point; since the current 3D printer extrusion nozzle movement mostly uses high-precision stepping motors, its control accuracy can reach 0.02mm, and the contact of the limit switch at the positioning point The dot area is about 2mm*2mm, so the host computer can easily control the movement of the extrusion nozzle to any specified position through this method; in addition, the G-code file (containing the coordinate information of each positioning point) for balance adjustment can be written at one time. use many times.

Usually, the upper surface shape of the hot bed of the 3D printer is a regular polygon, such as a rectangle, a rhombus, etc.; apex; when the upper surface of the heating bed of the 3D printer is circular, the preferred uniform distribution of the positioning points is at the inscribed polygon vertex of the upper surface of the heating bed circle; when the surface of the heating bed of the 3D printer is irregular shape, regular In the case of a polygon or a circle, the purpose of the invention can also be achieved if the three points of the positioning point are not on a straight line.

Further, the limit switch is a contact switch; it is on the same plane as the upper surface of the hot bed

Further, the microcontroller is connected to the feeding stepping motor of the extrusion nozzle, and when the feeding stepping motor of the extrusion nozzle performs a feeding action, it sends a pulse signal to the micro the controller sends information about the position of the extrusion nozzle; or,

The host computer sends the extrusion head position information to the microcontroller.

Preferably, the host computer is a PC host computer, a handheld touch screen host computer, an LCD button host computer or any other device that can realize the controllable movement of the extrusion nozzle. In some embodiments, the host computer mentioned in the present invention Computer and microcontroller can be integrated into one.

Further, the microcontroller includes at least one receiving port and at least one control output port; the receiving port is used to receive position information of the extrusion nozzle and/or position information of the hot bed positioning point; the control output port is used to control The bed anchor point is raised or lowered.

Further, the microcontroller includes a pulse receiving port, a location information receiving port of the positioning point having the same number as the positioning points, and a control output port having the same number as the positioning points;

The pulse receiving port is used to receive the position information of the extrusion nozzle in the form of a pulse from the extrusion nozzle;

Each positioning point position information receiving port corresponds to each positioning point one by one, and receives the positioning point position information of the corresponding positioning point;

Each control output port is in one-to-one correspondence with each positioning point, and controls the rise or fall of each positioning point respectively.

Further, the power device below or near the position of the positioning point of the heated bed is a stepping motor; the stepping motor is controlled by the microcontroller, and drives the positioning point of the heated bed to rise through a transmission device. or decline; preferably, the transmission device is a transmission screw; in the present invention, the stepper motor that realizes the rise or fall of the positioning point of the hot bed adopts a subdivision drive mode, and at the same time selects a transmission screw with a smaller pitch to drive and adjust the height of the hot bed. It has higher control precision.

But it should be declared that any device or method that can realize the rising and falling of the positioning point can be applied to the positioning point of the hot bed to realize the purpose of the present invention, so the protection scope of the present invention includes but not limited to driving the positioning point to rise or fall The device is a stepper motor.

Further, after the microcontroller receives the position information of the extrusion nozzle, according to the position information of the extrusion nozzle, the positioning point of the hot bed at the corresponding position is controlled to rise until the limit switch and the extrusion nozzle are close to the specified position. distance or full contact.

Further, after the microcontroller receives the position information of the positioning point, it stops the rising operation of the positioning point, and controls the positioning point to descend to a specified position or a specified distance.

The invention also provides a method for adjusting the balance of the hot bed of a 3D printer.

The upper computer controls the extrusion nozzle to move to the designated position;

After the extrusion nozzle reaches the designated position, the microcontroller obtains the position information of the extrusion nozzle;

The micro-controller controls the positioning point of the hot bed corresponding to the position of the extrusion nozzle to rise until the limit switch set at the positioning point and the extrusion nozzle approach within a specified distance or completely contact, the limit switch moves toward the specified position. The micro-controller sends the position information of the positioning point;

The micro-controller controls the fixed point of the heated bed to descend a specified distance.

Further, the extrusion nozzle first rises to a specified height (for example, at the beginning of calibration, it first rises by 3 mm), and then moves to a specified position within a plane. This method of first rising to a certain height and then moving in a plane can effectively avoid the uncontrolled mechanical collision between the extrusion nozzle and the hot bed during the automatic adjustment process.

Compared with prior art, the beneficial effect of the present invention:

1) For the existing 3D printer heating bed adjustment method, the present invention simulates the printing process by loading the G-code file, and directly uses the automatic leveling method to adjust the balance degree of the heating bed, which has the advantages of fast adjustment speed and simple operation The advantages. And the G-code file is written once and used many times.

2) Compared with the existing human eye visual inspection method, in the preferred solution of the present invention, stepper motor subdivision drive and transmission screw with smaller pitch are used to adjust the height of the hot bed positioning point, combined with high-precision limit switches, to realize the base of the 3D printer The precise adjustment of the balance between the hot bed and the plane of the movement path of the extrusion nozzle has higher accuracy than the existing human eye adjustment method.

3) A separate microcontroller is used to control the heat bed balance adjustment device, and the modular design is more convenient for debugging and maintenance of the device.

4) The G-code code can be programmed in the form of fixed-point and sent sentences one by one. By means of path setting, the mechanical collision during the automatic adjustment process is effectively avoided.

5) Directly refer to the working plane of the printing nozzle (instead of the horizontal plane), which ensures the balance between the 3D printer's hot bed and the plane of the extrusion nozzle's movement path.

Compared with the existing manual adjustment method, the present invention adopts a micro-control method to automatically complete the correction of the balance between the heated bed of the 3D printer base and the movement path plane of the extrusion nozzle. It has the advantages of fast speed, high precision and simple operation.

Description of drawings:

Fig. 1 is a structural block diagram of a 3D printer hot bed balance adjustment device in Embodiment 1 of the present invention

Fig. 2 is a structural block diagram of the microcontroller in Embodiment 1 of the present invention.

Fig. 3 is a top view of the moving path of the extrusion nozzle in Embodiment 1 of the present invention.

Fig. 4 is a working diagram of the 3D printer heating bed balance adjustment device in Embodiment 1 of the present invention.

Fig. 5 is a structural block diagram of the 3D printer heating bed balance adjustment device in the second embodiment.

FIG. 6 is a flow chart of a method for adjusting the balance of a heated bed of a 3D printer in Embodiment 3 of the present invention.

In the figure: 1-host computer, 2-microcontroller, 3-extrusion nozzle, 4-heating bed, 41-limit switch, A-first positioning point, B-second positioning point, C-third positioning Point, D-the fourth positioning point, 42-the positioning point stepping motor, 421-the first positioning point stepping motor, 422-the second positioning point stepping motor, 423-the third positioning point stepping motor, 424-the first Four positioning point stepping motor.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

Embodiment 1: As shown in Figures 1 to 4, this embodiment provides a heat bed balance adjustment device for a 3D printer with a rectangular upper surface on the heat bed, the four vertices of the rectangular upper surface of the heat bed of the 3D printer A positioning point is respectively set at each position, which are respectively named as the first positioning point A, the second positioning point B, the third positioning point C, and the fourth positioning point D; at the same time, each positioning point is provided with a limit switch 41; In the embodiment, the limit switch 41 is a contact switch (such as a pressure-sensitive sensor, or other switch devices that can trigger signals through contact); it is on the same plane as the upper surface of the hot bed, and when the contact switches arranged at each positioning point follow When the positioning point rises and touches the extrusion nozzle 3, the contact switch is triggered and sends a signal to the microcontroller 2; as in this embodiment, at the first positioning point A, the second positioning point B, A first limit switch 41 , a second limit switch 41 , a third limit switch 41 and a fourth limit switch 41 are arranged at the third positioning point C and the fourth positioning point D respectively.

The balance adjustment device also includes,

The upper computer 1 controls the 3D printer extrusion nozzle 3 to move to a specified position; the specified position is usually directly above each positioning point.

In some embodiments, when the extrusion nozzle 3 reaches the specified position (such as above any one of the first positioning point A, the second positioning point B, the third positioning point C or the fourth positioning point D), the host computer 1 Send the position information of the extrusion nozzle 3 to the microcontroller 2 (the position information of the extrusion nozzle 3 is used to tell the microcontroller 2 that the extrusion nozzle 3 has reached the specified position);

In the present embodiment, by connecting the lead wires at the feeding stepper motor of the extrusion nozzle 3 and connecting it to the microcontroller 2; The material stepping motor makes a feeding action, so that the extruding nozzle 3 feeds the stepping motor and sends a pulse signal through the lead wire; when the microcontroller 2 receives the pulse signal, it is determined that the extruding nozzle 3 has reached the designated position . Further, in this embodiment, the microcontroller 2 counts the received pulse signals, corresponds the number of received pulse signals to the positioning points one by one, and judges whether the current extrusion nozzle 3 is based on the number of received pulse signals. Which positioning point is located above; for example, when the extrusion nozzle 3 reaches above the first positioning point A, a pulse signal is sent, and the pulse signal count in the microcontroller 2 is 1, and the extrusion nozzle 3 has reached the first positioning The information above point A; when the extrusion nozzle 3 reaches above the second positioning point B, a pulse signal is sent again, the microcontroller 2 receives the pulse signal for the second time, and the pulse signal count is 2, and the extrusion nozzle 3 is obtained The information above the second positioning point B has been reached; when the extrusion nozzle 3 reaches above the third positioning point C, a pulse signal is sent again, and the microcontroller 2 receives the pulse signal for the third time, and the pulse signal count is 3. Output the information that the extrusion nozzle 3 has reached above the third positioning point C; when the extrusion nozzle 3 reaches above the fourth positioning point D, a pulse signal is sent again, and the microcontroller 2 receives the pulse signal for the fourth time, and the pulse signal The count is 4, and the information that the extrusion nozzle 3 has reached above the fourth positioning point D is obtained.

The microcontroller 2 receives the position information of the extrusion nozzle 3 and the location information of the hot bed positioning point, and controls the heating bed positioning point to rise or fall to a designated position; in this embodiment, as shown in Figure 2, the microcontroller includes One pulse receiving port, four positioning point position information receiving ports and four control output ports; the pulse receiving port is used to receive the pulse signal sent by the extrusion nozzle 3; the microcontroller 2 passes the received pulse The counting of the signal judges which positioning point the current extrusion nozzle 3 is located on, and performs an upward operation on the positioning point; the four positioning point position information receiving ports are respectively connected to the contact switches of the four positioning points; when any positioning point When the contact switch of the point rises with the positioning point to contact with the extrusion nozzle 3, the contact switch is triggered and sends a signal to the microcontroller 2 (the signal is the position information of the positioning point), and the corresponding position of the microcontroller 2 After receiving the signal at the information receiving port, control the corresponding positioning point to stop rising through the corresponding control output port, and then descend by a specified distance, such as 3mm; it should be noted that the descending distance should be set according to needs, and it can be 0.

It should be noted that the host computer 1 controls the extrusion nozzle 3 to move sequentially above the four positioning points (as shown in Figure 3, the process can be, from the first positioning point A to the second positioning point B , after moving to the third positioning point C, and finally moving to the fourth positioning point D), the extrusion nozzle 3 is always in the same plane; every time the extrusion nozzle 3 reaches a positioning point, the microcontroller 2. Control the stepping motor arranged below the positioning point to rise, so that the trigger switch at the positioning point contacts the extrusion nozzle 3; when the trigger switch contacts the extrusion nozzle 3, the The microcontroller 2 sends a signal (the signal is the position information of the positioning point), the microcontroller 2 stops rising after receiving the signal, and makes the positioning point descend by controlling the stepping motor below the positioning point A specified distance (in this embodiment, after the four positioning points are in contact with the extrusion nozzle 3, they all drop by 3mm) to break away from the extrusion nozzle 3; since the extrusion nozzle 3 moves in a plane, when the heat After the above steps are completed at the four positioning points of the bed 4, the upper surface thereof can be parallel to the movement plane of the extrusion nozzle 3, that is, the balance adjustment of the hot bed 4 is completed.

Further, in order to avoid an unplanned (or uncontrolled) mechanical collision between the extruding nozzle 3 and the hot bed 4 when moving in parallel, the host computer 1 controls the extruding nozzle 3 to rise for a specified distance before proceeding Parallel movement, such as, the upper computer 1 first controls the extrusion nozzle 3 to rise by 3mm and then moves in parallel to above the positioning point; the rising operation of the general extrusion nozzle 3 occurs at the origin as shown in Figure 3; because Figure 3 is The displacement diagram is viewed from above, so it fails to show the vertical upward movement of the extrusion nozzle 3 at the origin.

In addition, in this embodiment, the stepper motor that realizes the rise or fall of the hot bed positioning point adopts a subdivision drive mode, and at the same time, a transmission screw with a small pitch is selected as the transmission device to control and adjust the hot bed positioning point, which has higher control. Accuracy, as is well known, the stepper motor that realizes the rise or fall of the positioning point of the hot bed includes a driver chip, and the microcontroller 2 realizes the control of the stepper motor through the driver chip.

In this embodiment, the host computer 1 controls the movement of the extrusion nozzle 3 by loading the G-code file, and controls the position of the extrusion nozzle 3 by simulating the printing process, as recorded in the G-code file With the coordinate information of the positioning point of the hot bed, the upper computer 1 can directly control the extrusion nozzle 3 to move above the positioning point; since the current 3D printer extrusion nozzle 3 mostly uses high-precision stepping motors, its control accuracy can reach 0.02 mm, the contact area of the limit switch 41 at the positioning point is about 2mm*2mm, so the host computer 1 can easily control the movement of the extrusion nozzle 3 to any designated position in this way; in addition, the G- for balance adjustment The code file (containing the coordinate information of each positioning point) can be written once and used multiple times.

In this embodiment, the microcontroller 2 can be implemented with a 51 single-chip microcomputer, AVR, STM32 or ARM. At the same time, the host computer can be a PC host computer, a handheld touch screen host computer, an LCD button host computer or any other device that can operate the extrusion nozzle to make a controllable movement.

It should be noted that, in some embodiments, the functions of the host computer and the microcontroller mentioned in the present invention can be realized by the same device.

Embodiment 2: This embodiment still takes the heated bed of a 3D printer whose upper surface is rectangular as an example. The difference between this embodiment and Embodiment 1 is that the host computer 1 controls the extrusion nozzle 3 to reach above the positioning point. , the upper computer 1 sends the position information of the extruding nozzle 3 to the microcontroller 2; It is only a pulse signal, and the microcontroller 2 judges which positioning point the current extrusion nozzle 3 is located on by counting the received pulse signal; and in this implementation, the position information of the extrusion nozzle 3 also includes the positioning point number information, that is, the upper position When the machine 1 notifies the microcontroller 2 that the extrusion nozzle 3 has reached above the positioning point, it will inform the microcontroller 2 which positioning point the current extrusion nozzle 3 is located on, as shown in Figure 5. In this embodiment, the The micro-controller 2 only includes a positioning point control port and a positioning point position information receiving port; the positioning point control port is connected to the stepping motors of all positioning points at the same time; 3 Position information to determine which anchor point stepper motor is specifically operated, and determine which anchor point position information is sent by the limit switch 41 of which anchor point.

At the same time, in this embodiment, the limit switch 41 set at the positioning point is a magnetic sensitive switch. In this embodiment, a magnet is arranged on the extrusion nozzle 3, and when the positioning point rises, it reaches a certain distance from the extrusion nozzle 3. When it is inside, the magnetic sensitive switch is triggered and sends a signal (location information of the positioning point) to the microcontroller; the microcontroller 2 stops the rising operation of the positioning point after receiving the signal.

Embodiment 3: This embodiment provides a 3D printer heat bed balance adjustment method for the rectangular heat bed mentioned in embodiment 1,

The upper computer 1 controls the extrusion nozzle 3 to move to the designated position;

After the extrusion nozzle 3 reaches the designated position, the microcontroller obtains the position information of the extrusion nozzle 3;

The micro-controller controls the positioning point of the hot bed corresponding to the position of the extrusion nozzle 3 to rise until the limit switch 41 set at the positioning point and the extrusion nozzle 3 approach within a specified distance or completely contact, the limit The switch 41 sends the positioning point position information to the microcontroller 2;

The micro-controller controls the fixed point of the heated bed to descend a specified distance.

Further, the extrusion nozzle 3 first rises to a specified height (for example, at the beginning of calibration, it first rises by 3mm), and then moves to a specified position within a plane. This method of first rising to a certain height and then moving in a plane can effectively avoid unplanned (or uncontrolled) mechanical collisions between the extrusion nozzle 3 and the hot bed 4 during the automatic adjustment process.

Specifically, the processing steps of the microcontroller are as shown in Figure 6:

S101: set the pulse count in microcontroller 2 to 0;

S102: Microcontroller 2 receives the pulse signal, and the pulse signal is incremented by 1:

S103: The corresponding positioning point rises; this operation is realized by controlling the corresponding positioning point stepping motor, for example, when the extrusion nozzle is at the first positioning point A, operate the first positioning point stepping motor 421 to realize the corresponding positioning point rising, Decline; when the extrusion nozzle is at the second positioning point B, operate the second positioning point stepper motor 422 to realize the rise and fall of the corresponding positioning point; when the extrusion nozzle is at the third positioning point C, operate the third positioning point The stepper motor 423 is used to realize the rise and fall of the corresponding positioning point; when the extrusion nozzle is at the fourth positioning point D, the stepping motor 424 of the fourth positioning point is operated to realize the rising and falling of the corresponding positioning point;

S104: Determine whether the limit switch 41 of the positioning point is triggered, if not, keep the rising operation of S103, if so, enter step S105;

S105: Stop the rising of the anchor point and lower the position of the anchor point by a specified distance. In this embodiment, the descending distance is 3 mm.

S106: Determine whether a new pulse signal is received, and if so, return to step S102; otherwise, wait for the end of the timeout.

Further, while the microcontroller is performing the above processing, the upper computer 1 performs the following operations:

S201: Before and after the execution of step S101, control the extrusion nozzle 3 to move to the origin position shown in Figure 3, which is not above the hot bed 4; the host computer 1 controls the extrusion nozzle 3 to rise a specified distance to avoid subsequent When the extrusion nozzle 3 moves above the hot bed 4, it sends an uncontrolled mechanical collision with the hot bed 4;

S202: Move the extrusion nozzle 3 above the first positioning point A according to a predetermined path, and control the extrusion nozzle 3 to perform a feeding action, so that the feeding stepping motor of the extrusion nozzle 3 sends a pulse signal to the microcontroller ;

The time it takes for the extrusion nozzle 3 to move from the origin to above the first positioning point A and the time for the extrusion nozzle 3 to stay above the first positioning point A can be controlled by setting the G-code file. In this embodiment, The extrusion nozzle 3 stays on each positioning point and the time is set to 5S; at the same time, after the microcontroller receives a pulse count, it will ignore the pulse signal received again in the next 5S; that is, the microcontroller receives After one pulse signal is received, other pulse signals sent by the extrusion nozzle 3 during the dwell time above the same positioning point are ignored.

S203: Control the extrusion nozzle 3 to move above the second positioning point B in the same plane, control the extrusion nozzle 3 to perform a feeding action and stay for 5s;

S204: Control the extrusion nozzle 3 to move above the third positioning point C in the same plane, control the extrusion nozzle 3 to perform a feeding action and stay for 5s;

S205: Control the extrusion nozzle 3 to move above the fourth positioning point D in the same plane, control the extrusion nozzle 3 to perform a feeding action and stay for 5s;

S206: Stop the operation or stop the operation after controlling the extrusion nozzle 3 to return to the origin.

It should be noted that, as shown in Figure 4, in the present invention, the stepper motor that controls the rise and fall of the positioning point is not limited to be directly below the positioning point, as long as it is located near the positioning point, it can drive the positioning point to rise and fall The purpose of the invention can be realized. It should be stated that since the positioning point is only the area demarcated on the hot bed (the limit switch is set in this area), any description of the rise and fall of the positioning point in the present invention refers to the area of the heating bed that includes this area. up or down.

In addition, this invention can not only be used on 3D printers, any device that uses a nozzle and has a flat working platform, such as an industrial glue dispenser, an industrial screw machine, etc., can apply the device and method provided by the invention to the flat working platform and the nozzle. The balance of the motion plane is adjusted to improve the operation accuracy and product yield.

Claims (7)

1. A 3D printer hot bed balance adjustment device, the upper surface of the hot bed is provided with more than three positioning points, and wherein at least three positioning points are not on the same straight line; it is characterized in that, comprising, The upper computer controls the movement of the 3D printer extrusion nozzle to the designated position; The microcontroller receives the position information of the extrusion nozzle and the position information of the hot bed positioning point, and controls the heating bed positioning point to rise or fall to the specified position; The limit switch is set at the positioning point of the hot bed; when the limit switch is within a specified distance or in full contact with the extrusion nozzle, it sends position information of the positioning point to the microcontroller; The microcontroller is connected with the feeding stepping motor of the extrusion nozzle, and when the feeding stepping motor of the extrusion nozzle performs a feeding action, it sends a pulse signal to the microcontroller. extrusion nozzle location information; or, The host computer sends the position information of the extrusion nozzle to the microcontroller; After the microcontroller receives the position information of the extrusion nozzle, it controls the positioning point of the hot bed at the corresponding position to rise according to the position information of the extrusion nozzle until the limit switch is close to the extrusion nozzle by a specified distance or completely. touch; After receiving the position information of the positioning point, the microcontroller stops the rising operation of the positioning point, and controls the positioning point to descend to a specified position or a specified distance. 2 . The 3D printer hot bed balance adjustment device according to claim 1 , wherein the limit switch is a contact switch; it is on the same plane as the upper surface of the hot bed. 3 . 3. The 3D printer hot bed balance adjustment device as claimed in claim 1, wherein the microcontroller includes at least one receiving port and at least one control output port; the receiving port is used to receive the extrusion nozzle position information And/or the location information of the fixed point of the heated bed; the control output port is used to control the rise or fall of the fixed point of the heated bed. 4. The 3D printer hot bed balance adjustment device as claimed in claim 3, wherein the microcontroller includes a pulse receiving port, an anchor point position information receiving port with the same number of anchor points, and the same number of anchor points as the number of anchor points. The control output port; The pulse receiving port is used to receive the position information of the extrusion nozzle in the form of a pulse from the extrusion nozzle; Each positioning point position information receiving port corresponds to each positioning point one by one, and receives the positioning point position information of the corresponding positioning point; Each control output port is in one-to-one correspondence with each positioning point, and controls the rise or fall of each positioning point respectively. 5. The 3D printer heating bed balance adjustment device as claimed in claim 1, wherein a stepping motor and a transmission device are arranged at the positioning point of the heating bed; the stepping motor is controlled by the microcontroller , and drive the positioning point of the hot bed to rise or fall through the transmission device. 6. A method for applying the 3D printer hot bed balance adjustment device according to any one of claims 1 to 5, characterized in that, The upper computer controls the extrusion nozzle to move to the designated position; After the extrusion nozzle reaches the designated position, the microcontroller obtains the position information of the extrusion nozzle; The micro-controller controls the positioning point of the hot bed corresponding to the position of the extrusion nozzle to rise until the limit switch set at the positioning point and the extrusion nozzle approach within a specified distance or completely contact, the limit switch moves toward the specified position. The micro-controller sends the position information of the positioning point; The micro-controller controls the fixed point of the heated bed to descend a specified distance. 7 . The method according to claim 6 , wherein the extrusion nozzle first rises to a specified height, and then moves to a specified position within a plane. 8 .