RU2793563C1 - Method for automatic calibration of 3d printer platform - Google Patents

Abstract

FIELD: control; monitoring of a 3D printer.

SUBSTANCE: control and monitoring of a 3D printer, in particular calibration of a 3D printer platform. Method for calibration uses a calibration mechanism fixed to the stationary part, having an upper part with a microservo drive that moves the lower part of the calibration mechanism from a horizontal position to an upright vertical one. After the electrical circuit between the upper and lower parts of the calibration mechanism is closed, the mechanism is moved to the upper left corner, coordinates are determined, then it is moved to the right, and these operations continue until the lower right corner of the platform is reached. Then the accumulated data in the control unit is analysed, the required number of revolutions of the servo drives that control the spring mechanisms for adjusting the height of the platform is calculated. When the specified positioning accuracy is reached, the microservo drive moves the lower part of the calibration mechanism back to the horizontal position.

EFFECT: increase in the accuracy of calibration while maintaining the accuracy and quality of printing throughout the use of the printer.

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Description

The invention relates to the field of control and monitoring of the elements of a 3D printer using inkjet 3D printing technology, and can be used when calibrating a 3D printer platform.

There is a known method for calibrating a 3D printer table [RU 2671374 C1, 10/30/2018], including calibrating the table to at least three calibration points by installing a desktop with calibration points on a holder frame, which is made with clamps, the number of which matches the number of calibration points , determining the zero position of the calibration level for the first calibration point by determining the zero position of the calibration level, which should be within the calibration of the first calibration point, then for each of the calibration points, including the first, the following operations are sequentially performed: loosen the lock of each point of the working platform, move calibration probe into each point of the working platform, lower the calibration probe to the zero position of the calibration level, firmly fix the calibration probe in the zero position of the calibration level, clamp the lock of each point of the working platform, while the shank of the working platform enters the groove of the calibration point lock and then the lock clamps it .

The disadvantage of this method is the inability to increase the calibration points without changing the design. To increase them, it is necessary to manufacture a new frame-holder and other elements, which is a high-cost process. Also, the disadvantage of the method is that such a mechanism as the print head is applied to compress the spring and thereby set the table in the desired position. Doing so may deform the print head and reduce print quality.

The closest method of the same purpose to the claimed invention in terms of a combination of features is the method for automatically calibrating the location of the three-dimensional printer platform, disclosed in patent RU No. 155203 dated September 27, 2015. According to the method, during calibration, the stationary part of the 3D printer is moved along a linear guide, which is fixed on the body of the 3D printer. An extrusion head is fixed at the bottom of the stationary part, including a radiator, a heating chamber and a nozzle, and having no more than two degrees of freedom. With a small weight of the extrusion head, a spring is also placed between it and the stationary part. The body of the sensor is fixed on the stationary part of the thermal printing head, and the actuating element, which ensures the operation of the sensor, is placed on the extrusion head. The sensor is triggered during the platform calibration process at the moment the extrusion head is raised by the value h, which is equal to the distance between the element acting on the sensor at the lowest position of the nozzle and the point of its entry into the sensor sensitivity zone. This method is taken as a prototype.

Signs of the prototype, coinciding with the essential features of the proposed method - a method for automatically calibrating the platform of a 3D printer, which consists in the fact that the stationary part of the 3D printer during calibration is moved along a linear guide fixed on the body of the 3D printer, while the extrusion head is fixed from below the stationary part , including a radiator and a nozzle, and having no more than two degrees of freedom, which is moved together with the stationary part up and down.

The disadvantages of the known method adopted as a prototype are as follows:

- when the extrusion head lifts up, not together with the stationary part, then it lifts up the thread that the printer prints with. This can cause you to lose control of how much material (filament) is in the extrusion head, resulting in poor print quality.

- To compress the spring, it is necessary to apply a large force that will act on the nozzle and the front of the printer platform, which can lead to their deformation and, as a result, to a deterioration in print quality.

- Since the connection of the stationary part and the extrusion head through a pair of sliding or rolling is not rigid, and the spring tends to stretch over time, it may cause the control of the actual position of the nozzle to be lost, and this may lead to printing defects.

The objective of the invention is to develop a method for automatically calibrating the platform of a 3D printer, which makes it possible to increase the accuracy of calibration while maintaining the accuracy and quality of printing throughout the use of this printer.

The features of the proposed technical solution, which are different from the prototype, are used for calibration fixed to the stationary part of the calibration mechanism, which has an upper part on which a microservo drive is installed that moves the lower part of the calibration mechanism from a horizontal position to a strictly vertical position by means of a cylindrical-type swivel, until , until the conductive conductors of the swivel are closed using the swivel circuit breaker; after closing the electrical circuit between the upper and lower parts of the calibration mechanism, the calibration mechanism is moved to the upper left corner and lowered down until the circuit breaker at the base of the calibration mechanism is closed to the conductive conductors of the calibration mechanism base; then, the coordinates at which the calibration mechanism stopped along the three axes X, Y, Z are determined using the standard means of a 3D printer; this data is transmitted to the control unit; after that, the calibration mechanism is lifted up and shifted a certain distance to the right within the platform; again repeat the operations of lowering down, closing the electrical circuit at the base of the calibration mechanism and transmitting data to the control unit until the lower right corner of the platform is reached; then the accumulated data in the control unit is analyzed and, according to the algorithms pre-installed in it, the required number of revolutions of the servo drives that control the spring mechanisms for adjusting the height of the platform lift installed at each corner of the platform are calculated; operations to determine the coordinates at each point continue until the user-specified positioning accuracy of the platform in the control unit is reached; then the control unit sends control signals to the servos, which produce a given number of revolutions, thereby acting on the spring mechanisms for adjusting the height of the platform; when the specified positioning accuracy is achieved by the microservo drive, the lower part of the calibration mechanism is moved back to the horizontal position.

The use of a calibration mechanism fixed to the stationary part of the printer, having an upper part on which a microservo drive is installed, moving the lower part of the calibration mechanism from a horizontal position to a strictly vertical position by means of a cylindrical-type swivel, until the conductive conductors of the swivel are closed using The swivel electrical circuit contactor allows at the time of calibration to firmly fix the calibration mechanism below the nozzle, and the microservo drive does not affect the accuracy of the calibration, since the strictly vertical position of the lower part of the calibration mechanism is determined based on the closure of the swivel conductive conductors, which leads to the possibility of automatic platform calibration 3D printer and increase the accuracy of calibration, while maintaining the accuracy and quality of printing throughout the use of this printer. At the same time, the calibration accuracy is further increased due to the fact that the number of points at which the coordinates are measured is not limited.

The method is illustrated by a drawing showing a general view of a 3D printer with a calibration mechanism. The drawing shows:

1 - 3D printer case

2 - 3D printer control unit

3 - Linear guide

4 - Stationary part

5 - Upper part of the calibration mechanism

6 - Microservo drive for turning the lower part of the calibration mechanism

7 - Cylindrical type swivel

8 - Conductive conductor (No. 1) swivel

9 - Electrical circuit breaker at the swivel joint

10 - Lower part of the calibration mechanism

11 - Conductive conductor (No. 2) of the base of the calibration mechanism

12 - Electrical circuit breaker at the base of the calibration mechanism

13 - Conductive conductor (No. 2) of the base of the calibration mechanism

14 - Conductive conductor (No. 1) swivel

15 - Rigid mount

16 - Radiator

17 - Nozzle

18 - 3D printer platform

19, 20 - Spring mechanisms for adjusting the height of the platform (4 in total, one in each corner of the platform, 3, 4 spring mechanisms are not shown in the drawing)

21 - Servo drive that controls the spring mechanism 19

22 - Servo drive that controls the spring mechanism 20 (4 in total, one in each corner of the platform, 3, 4 servos are not shown in the drawing)

The method for automatically calibrating the 3D printer platform is as follows.

During calibration, the stationary part 4 of the 3D printer is moved along the linear guide 3, fixed on the body of the 3D printer 1. From the bottom of the stationary part 4, an extrusion head is fixed with a rigid mount 15, including a radiator 16 and a nozzle 17, and having no more than two degrees of freedom. Also, a calibration mechanism is fixed to the stationary part 4, having an upper part 5, on which a microservo drive 6 is installed, moving the lower part 10 of the calibration mechanism from a horizontal position to a strictly vertical position by means of a cylindrical-type swivel joint 7, until the conductive swivel conductors 8, 14 using a swivel circuit breaker 9.

After closing the electrical circuit between the upper 5 and lower 10 parts of the calibration mechanism, the calibration mechanism is moved to the upper left corner and lowered down until the circuit breaker at the base of the calibration mechanism 12 is closed to the conductive conductors of the calibration mechanism base 11, 13. Then determination of the coordinates at which the calibration mechanism has stopped along the three axes X, Y, Z using the standard means of a 3D printer, and these data are transmitted to control unit 2. After that, the calibration mechanism is lifted up and shifted a certain distance to the right within the platform and the operations are repeated again lowering down, closing the electrical circuit at the base of the calibration mechanism and transmitting data to the control unit 2 until the lower right corner of the platform 18 is reached.

Then the accumulated data in the control unit 2 is analyzed and, according to the algorithms pre-installed in it, the required number of revolutions of the servo drives 21, 22 (and others that are not shown in the figure) that control the spring mechanisms for adjusting the height of the platform 19, 20 installed on each of corners of the platform 18. Operations to determine the coordinates at each point continue until the user-specified positioning accuracy of the platform 18 in the control unit 2 is reached.

Then the control unit 2 sends control signals to the servo drives 20, 21 (and others, which are not shown in Fig.), which produce a given number of revolutions, thereby acting on the spring mechanisms for adjusting the height of the platform 19, 20 (and others, which are not shown). in Fig.). At the same time, when the specified positioning accuracy is reached, the lower part 10 of the calibration mechanism is moved back to the horizontal position by the microservo 6.

Thus, the application of the proposed method provides an increase in the accuracy of calibration while maintaining the accuracy and quality of printing throughout the use of this printer.

Claims (1)

A method for automatic calibration of a 3D printer platform, which consists in moving the stationary part of the 3D printer during calibration along a linear guide fixed on the body of the 3D printer, while an extrusion head is fixed from below the stationary part, including a radiator and a nozzle and having no more than two degrees of freedom, characterized in that a calibration mechanism fixed to the stationary part is used for calibration, having an upper part on which a microservo drive is installed, moving the lower part of the calibration mechanism from a horizontal position to a strictly vertical position by means of a cylindrical-type swivel until they are closed swivel conductive conductors using a swivel electrical circuit closure, and after the electrical circuit is closed between the upper and lower parts of the calibration mechanism, the calibration mechanism is moved to the upper left corner and lowered down until the circuit breaker at the base of the calibration mechanism is closed to the conductive conductors the base of the calibration mechanism, then the coordinates at which the calibration mechanism has stopped are determined along the three axes X, Y, Z by standard means of a 3D printer, and this data is transmitted to the control unit, after which the calibration mechanism is lifted up and shifted a certain distance to the right in within the platform and again repeat the operations of lowering down, closing the electrical circuit at the base of the calibration mechanism and transmitting data to the control unit until the lower right corner of the platform is reached, then the accumulated data in the control unit is analyzed and the algorithms pre-installed in it calculate the required number of revolutions of the servo drives that control the spring mechanisms for adjusting the height of the platform, installed at each of the corners of the platform, and operations to determine the coordinates at each point continue until the platform positioning accuracy specified by the user in the control unit is reached, then the control unit sends control signals to the servo drives, which produce a given number of revolutions, thereby acting on the spring mechanisms for adjusting the height of the platform, and when the specified positioning accuracy is reached, the lower part of the calibration mechanism is moved back to the horizontal position by the microservo drive.

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