KR101572185B1 - Apparatus and method for automatic monitoring of filament feeding in FDM 3D printer - Google Patents

Abstract

The present invention relates to an apparatus and method for automatically monitoring filament conveyance in an FDM 3D printer, and more particularly, to an apparatus and method for automatically monitoring filament conveyance in an FDM 3D printer, And compares the target feeding speed of the filament determined by the print command or the filament feeding command with the measuring speed detected through the encoder wheel and the encoder sensor to determine whether the printing stop command or the filament feeding stop If it is determined that the printer itself can be calibrated even though it is not normal, the feed and feed detection operation is performed and the printer itself can be calibrated If not, stop the filament feeding operation The present invention provides a device and method for detecting a transfer of a filament that notifies a user of a high error state, waits until a problem is solved, and then performs a printing operation or a filament conveying operation when the problem is solved.
Accordingly, it is possible to eliminate the inconvenience of estimating the completion of the output with the remaining filaments before starting the printing of the conventional 3D printer.

Description

TECHNICAL FIELD [0001] The present invention relates to an automatic monitoring apparatus and method for filament feeding of an FDM 3D printer,

The present invention relates to an apparatus and method for automatically monitoring filament transport in a 3D printer, and more particularly, to a method and apparatus for automatically stopping a printing operation when a supply of filaments is interrupted or a feeding problem occurs, And more particularly, to an apparatus and method for automatically monitoring the feeding of filaments of an FDM 3D printer capable of real-time monitoring of feeding and feeding of filaments so that the filaments can be conveyed.

Generally, to produce prototype with three dimensional shape, there is a method of making by hand and a method by CNC milling depending on the drawing. However, since the method of making the woodwork is by hand, elaborate numerical control is difficult and time consuming, and the CNC milling method is capable of precise numerical control, but there are many shapes that are difficult to process due to tool interference. Therefore, recently, a so-called three-dimensional printer method of fabricating prototypes of a three-dimensional shape using a computer storing data generated in a three-dimensional modeling produced by product designers and designers has emerged.

In this type of three-dimensional printer, SLA (Stereo Lithography Apparatus) which uses the principle that the scanned portion is cured by injecting the laser beam to the photo-curable resin, and a functional polymer or metal powder instead of the photo- SLS (Selective Laser Sintering), which uses the principle of solidification by injection, and Laminated Object Manufacturing (LOM), which cuts glue-coated paper using a laser beam in a desired cross-section, , Ballistic Particle Manufacturing (BPM) using inkjet (Ink-Jet) printer technology, and Fused deposition modeling (FDM) method in which molding material is melted and heated by using heated nozzles.

The filament, which is the raw material of the FDM type 3D printer, is processed by melting the heat-dissipating material into a thin yarn and winding it on a spool. It dissolves the feeder and the filament that feed the filament, And a filament, which is wound around the spool, is continuously fed through the feeder to be injected into the nozzle, and the filament injected into the nozzle is fed to the nozzle, The filaments in the liquid state are injected to form an image by the movement of the carrier and the bed so that a three-dimensional output is formed as a result.

In the FDM type 3D printer, the filament fed from the spool must be fed continuously without any abnormality until the output is completed, but when the filament wound on the spool is short, the filament is tangled, or the feeding of the filament is stopped due to other abnormality And the time required for completing the output varies depending on the size of the output and the performance of the printer. Typically, it takes several tens of minutes to several tens of hours. This is because even if the feeding of the filament is stopped during printing, One filament may not be outputted, so that the printout that has been printed for a long time can not be used as an unfinished product, resulting in time-wasting and waste of material.

1. Screen printer having a 3D inspection device (Application No. 10-2010-0015349) 2. THREE-DIMENSIONAL PRINTER (Application No. 10-2012-7012134) 3. Three-Dimensional Printer (Application No. 10-2008-0019551)

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a filament feeding device capable of stopping a printing operation when a problem occurs in supplying and transporting filaments, And to provide an automatic monitoring apparatus and method for the filament conveyance of an FDM 3D printer.

Further, according to the present invention, by using a pulse signal of a feeder for feeding filaments, a monitoring roller rotated by feeding filaments at a front end or a rear end of a feeder, an encoder wheel connected to the feeder and an encoder sensor for detecting rotation of the encoder wheel, The FDM 3D printer can automatically measure the rotation speed of the filament and check the operation of the filament by comparing it with the target conveying speed of the filament, thereby saving time and materials according to the unfinished output. .

However, the objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above object, an apparatus for automatically monitoring filament conveyance of an FDM 3D printer according to an exemplary embodiment of the present invention includes a heater nozzle for melting and injecting filaments, a feeder for transferring filaments from a spool to a heater nozzle, A bed for loading the output formed while the filament injected from the heater nozzle naturally cures and a carrier having a heater nozzle mounted thereon for realizing the shape of the output on the bed is moved to the printing position And the feeder is connected to a heater nozzle coupling part through a filament conveying path, the automatic monitoring apparatus for an automatic filament conveyance of an FDM 3D printer, So that the pressure is applied between the monitoring roller, the idler roller, And the filament is conveyed by the power of the feeder, and when the fed filament passes between the monitoring roller and the idle roller, when the monitoring roller is rotated by the frictional force between the monitoring roller and the filament, And an encoder sensor for detecting the rotation of the encoder wheel and generating a pulse signal.

In order to accomplish the above object, an automatic method for monitoring filament conveyance in an FDM 3D printer according to an embodiment of the present invention is characterized in that when the detection of the filament wound on the spool is started, the filament is transferred according to a print command or a command for transferring filaments A first step of calculating error determination reference speeds Vth1 and Vth2 for the detected conveying speeds using the target speed Vm to be measured and the tolerance ratios? And? A second step of checking whether or not the actual filament conveying speed Vs is detected through a signal generated from the encoder wheel and the encoder signal, and waiting until the actual filament conveying speed Vs is detected if it is not detected; If the feed speed Vs is larger than the first error reference speed Vth1 (Vs > Vth1) by comparing the detected feed speed Vs with the first error reference speed Vth1 when the feed speed of the filament is detected, A third step of comparing with a secondary error judgment reference speed Vth2; After the third step, if the feeding speed Vs is larger than the second error reference speed Vth2 (Vs > Vth2), the feeding operation of the filament proceeds and the filament is stopped or filament feeding is stopped. And terminating the filament conveyance detecting operation if the conveying operation is stopped.

The apparatus and method for automatically monitoring filament transport in an FDM 3D printer according to an embodiment of the present invention are characterized in that when a problem occurs in supply of filaments, the printing operation is stopped, and when the problem is removed, It is possible to monitor in real time whether the filament is fed or not, so that the filament can be continuously conveyed until the output is completed according to the normal supply.

The apparatus and method for automatically monitoring filament conveyance in an FDM 3D printer according to the present invention include a feeder for feeding filaments, a monitoring roller rotated by feeding filaments at a front end or a rear end of a feeder, By measuring the rotation speed of the encoder using the pulse signal of the encoder sensor that senses the rotation of the wheel, it is possible to compare the target conveying speed of the filament to check the operation of the filament conveying and operation, thereby saving time and materials according to the unfinished output It provides an effect that can be done.

In addition, the apparatus and method for automatically monitoring the filament transport of the FDM 3D printer according to the present invention have the effect of eliminating the need to estimate the completion of the output with the remaining filaments before the start of printing of the conventional 3D printer .

1 is a perspective view showing a configuration of a general FDM 3D printer;
2 is a schematic view showing a filament supply path of an FDM type 3D printer
3 is a schematic view of a filament conveyance sensing apparatus of an FDM 3D printer according to a first embodiment of the present invention.
4 is a schematic view of a filament conveyance sensing apparatus of an FDM 3D printer according to a second embodiment of the present invention.
FIG. 5 is a flowchart illustrating a filament conveyance detection method of an FDM 3D printer according to the present invention. FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a detailed description of preferred embodiments of the present invention will be given with reference to the accompanying drawings. In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

FIG. 1 is a perspective view showing a configuration of an FDM 3D printer, and FIG. 2 is a schematic view showing a filament supply path of an FDM type 3D printer through the configuration of FIG. Referring to FIGS. 1 and 2, the operation of the FDM 3D printer includes a heater nozzle 10 for melting and injecting the filament 32, a filament 32 extending from the spool 30 to the heater nozzle 10 A carrier 20 for mounting and moving the heater nozzle and a bed 20 for loading the output formed while the filament 32 injected from the heater nozzle 10 spontaneously cures, A X-axis, a Y-axis, and a Z-axis driving unit for moving the carrier 2, on which the heater nozzle 10 is mounted, to the printing position to implement the shape of the output on the bed 20, Is connected to the heater nozzle coupling portion (15) through a filament conveyance path.

The X-axis, Y-axis, and Z-axis driving units are configured to transfer the power generated from the motor to the carrier 2 and the bed 20 to move the heater nozzle to the corresponding printing position.

2, the filament 32 wound around the spool 30 is conveyed to the heater nozzle 10 through the feeder 40 by the operation of the feeder 40. At this time, The feed roller 42 and the idle roller 44 connected to the motor (not shown) can be constituted by a spring member 46 for applying a force between both rollers. The feed roller 42 rotates in accordance with the driving of the motor, and a frictional force due to the spring tension and the action is generated, thereby transferring the filament. The filament 32 wound around the spool 30 is manually fed from the spool 30 to the feeder 40 and the filament 32 injected into the heater nozzle 10 is heated by the heat of the heater So that the printing process is performed.

FIG. 3 is a schematic view of a device for automatically detecting the filament conveyance of the FDM 3D printer according to the first embodiment of the present invention. Referring to FIGS. 1 to 3, Four rollers 42, 44, 52 and 54 are provided between the filament 32 and the heater nozzle 10 so as to convey the filament 32 and monitor the feeding.

More specifically, the automatic filament conveyance monitoring device may be installed upstream of the feed or selectively downstream of the feed.

The feeder 40 includes a spring member 46 for applying an interaction force between the feed roller 42 and the idle roller 44 and a roller and a motor (not shown) for applying power to the feed roller 42 When the feed roller 42 connected to the motor is rotated according to the rotation of the motor, the frictional force generated between the feed roller 42 and the filament 32 by the action of the spring member 46, And the filament is passed between the sensing roller 52 and the idle roller 56, the sensing roller 52 is rotated by the interaction force with the spring member 56. At this time, The connected encoder wheel 50 rotates and the encoder sensor 51 generates a signal in accordance with the rotation of the encoder wheel 50.

In addition, the encoder wheel 50 may be coaxially connected to the monitoring roller 52, may be composed of the same parts, or may be connected by power transmission means such as a gear or a belt.

A CPU (not shown) inside the monitoring apparatus measures the rotation speed of the encoder wheel 50 using the signal generated from the encoder sensor 51, and converts the rotation speed of the encoder wheel 50 to the feeding speed of the filament.

FIG. 4 is a schematic view of an automatic filament conveying apparatus for an FDM 3D printer according to a second embodiment of the present invention. Referring to FIGS. 1 to 4,

The feed roller 42, the idler roller 44 and the spring member 46 for feeding the filaments 32 are provided in the same manner as in the first embodiment except that the monitoring roller 52 is provided on the feed roller 42 And the monitoring roller 52 is rotated by the rotation of the idle roller 44 by being connected to the idle roller 44 corresponding thereto.

More specifically, when the feed roller 42 connected to the motor is rotated according to the rotation of the motor (not shown), the feed roller 42 and the filament 32 are rotated by the action of the spring member 46, And the idler roller 44 is rotated by the frictional force between the filament and the idler roller 44. The idler roller 44 is rotated by the frictional force between the filament and the idler roller 44,

At this time, the monitoring roller 52 connected to the idle roller 44 is rotated in synchronism with the idle roller 44 so that the encoder wheel 50 is rotated and a signal is generated through the encoder sensor 51 do.

The idler roller 44 and the encoder wheel 50 may be connected to each other in direct contact with each other or may be connected using power transmission means such as a gear or a belt.

In addition, the monitoring apparatus may be configured to prevent the idler roller 44 from rotating even when the motor rotates without a filament between the feed roller 42 and the idler roller 44. In order to prevent the idler roller 44 from rotating, And a gap X is maintained.

That is, 0 < x < Df

The operation of the filament conveyance detecting method of the FDM 3D printer as the filament 32 wound on the spool 30 is conveyed to the heater nozzle 10 will be described in detail with reference to the flowchart of FIG. 5 .

First, when the feed detection operation is started, the error determination reference speeds Vth1 and Vth2 are determined by the feed target speed Vm of the filament determined according to the print command or the feed command of the filament and the tolerance ratios? And? .

The rotation speed Vm of the encoder wheel 50 corresponding to the linear velocity Vf of the filament 32 is

Vm = Vf / (rs *? Ds)

     rs is the reduction ratio of the encoder drive system,

Ds represents the diameter of the monitoring roller.

Vth1: The reference speed that can not be corrected by the printer itself and can be determined as a state requiring correction by the user is

Vth1 = Vm *?

      α is determined by the experimental value,

Vth1 is an abnormal operation, and the feed rate reference value of the filament that needs to be externally corrected

Vth2: The judgment reference speed at which the printer itself can judge that the correction is possible,

Vth2 = Vm *?

      β is determined by the experimental value,

Vth2 is the reference value of the feed rate of the filament which is not normal but can be corrected by itself.

The determination reference speeds Vth1 and Vth2 obtained through the calculation process are compared with the measurement speed Vs detected by the signal of the encoder sensor 51 and used as a reference for performing the process.

If Vs < = Vth1: Since the printer is unable to correct the filament in accordance with the feeding, the user is subjected to an error process for not compensating the printer itself, including notifying the user of the error status. Vth1), the operation for detecting the feed speed is continued

   If Vs < = Vth2, the feeding of the filament is not normal but the compensation is possible in the printer itself, such as adjusting the temperature of the heater nozzle or adjusting the current of the motor.

If Vs > Vth2: If the filament is normally fed, it is checked whether the feeding of the filament is stopped by a command such as printing stop or filament feeding stop. If the state is stopped, the filament feeding detecting operation is ended. If not, continue the feed detection operation.

The target rotation speed Vm of the encoder wheel 50 and the signal of the encoder sensor 51 corresponding to the target conveying linear velocity Vf of the filament determined in accordance with the print command or the command for feeding the filament 5, which is based on the measured rotation speed Vs of the encoder wheel 50 detected by the encoder wheel 50, the filament 32 wound on the spool 30 is rotated in the clockwise direction, The target rotation speed Vm of the encoder wheel corresponding to the target transfer linear velocity Vf of the filament determined according to the print command or the transfer command of the filament and the tolerance ratios? And? The error determination reference speeds Vth1 and Vth2 for the detected conveyance speeds are calculated (refer to step S10)

Thereafter, it is checked whether or not the feed speed Vs of the actual filament 32 is detected through the signal generated from the encoder wheel 50 and the encoder sensor 51. If the feed speed Vs of the actual filament 32 is not detected, See steps)

The method of detecting the rotational speed of the encoder wheel 50 includes a method of using the number of pulse signals generated from the encoder sensor for a predetermined time and a method of measuring the time between the pulse signals generated by the encoder sensor 51 and using the same.

When the feed speed of the filament 32 is detected, the detected feed speed Vs is compared with the first error reference speed Vth1 (refer to step S30). If the feed speed Vs is less than the first error reference speed Vth1) (Vs < = Vth1), the printer itself can not perform correction, and therefore error processing for not compensating the printer itself including informing the user of the error status is performed (refer to step S40)

Thereafter, the operation for detecting the feed speed is continued until the feed speed Vs becomes larger than the primary error determination reference speed Vth1 by an external measure such as supplying a new filament or removing the tangled portion of the filament. (Refer to step S45)

If the feed speed Vs is larger than the first error reference speed Vth1 (Vs > Vth1), the feed speed Vs is compared with the second error reference speed Vth2 (see step S50) (Vs < = Vth2), the filament is not normally transported. However, since the printer itself can compensate the temperature of the heater nozzle or adjust the current of the motor, (Step S60) and returns to step S50.

If the feeding speed Vs is larger than the second error judgment reference speed Vth2 (Vs > Vth2), the feeding operation of the filament is normally performed. If the feeding operation is stopped normally or the filament feeding is stopped, (Refer to step S70), and if it is in the stopped state, terminates the filament conveyance sensing operation.

If the target speed Vm has not been changed, the process returns to step S20 and repeats the above step. If the target speed Vm has not been changed, And then a new error judgment reference speed is calculated and then the above operation is repeated.

As described above, preferred embodiments of the present invention have been disclosed in the present specification and drawings, and although specific terms have been used, they have been used only in a general sense to easily describe the technical contents of the present invention and to facilitate understanding of the invention , And are not intended to limit the scope of the present invention. It is to be understood by those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

10: heater nozzle 15: heater nozzle coupling part
20: Bad 30: Spool
32: filament 34: filament feed path 40: feeder 42: feed roller
44: idler roller 46: spring member
50: Encoded wheel 51: Encoded sensor
52: monitoring roller 54: idler roller
56: spring member

Claims (7)

delete delete When the feeding detection operation of the filament 32 wound on the spool 30 is started, the target rotation speed Vf of the encoder wheel 50 corresponding to the target feeding linear velocity Vf of the filament determined according to the printing command or the filament feeding command, (Vth1, Vth2) with respect to the detected conveying speed using the tolerance ratios? And? Obtained from the experimental value (Vm) and the experimental value;
A second step of checking whether the actual filament conveying speed Vs is detected through a signal generated from the encoder wheel 50 and the encoder sensor 51 and waiting until it is detected if it is not detected;
When the feeding speed of the filament 32 is detected, the detected feeding speed Vs is compared with the primary error judgment reference speed Vth1. If the feeding speed Vs is larger than the primary error judgment reference speed Vth1 Vs > Vth1) second error determination reference speed (Vth2);
After the third step, if the feeding speed Vs is larger than the second error reference speed Vth2 (Vs > Vth2), the feeding operation of the filament proceeds and the filament is stopped or filament feeding is stopped. And terminating the filament conveyance sensing operation if the conveyance of the filament is stopped. The method of claim 1,
The method of claim 3,
The target rotational speed Vm of the encoder wheel 50 corresponding to the filament target transfer linear velocity Vf determined by the print command in the first step or the filament transfer command and the tolerance ratios? The error judgment reference speeds Vth1 and Vth2 are
The target rotation speed Vm of the encoder wheel 50 corresponding to the filament target transfer linear velocity Vf in the first step is
Vm = Vf / (rs *? Ds)
rs is the reduction ratio of the encoder drive system,
Ds is the diameter of the monitoring roller,

Vth1 = Vm *?
α is determined by the experimental value,
Vth1 is an abnormal operation, and the feed rate reference value of the filament that needs to be externally corrected

Vth2 = Vm *?
β is determined by the experimental value,
Vth2 is set to the feed rate reference value of the filament which is not normal but can be corrected by itself,

In the second step
Is compared with the measured speed (Vs) detected by the signals of the encoder wheel (50) and the encoder sensor (51)
If Vs < = Vth1: Since the printer is unable to correct the filament in accordance with the feeding, the user is subjected to an error process for not compensating the printer itself, including notifying the user of the error status. Vth1), the operation of detecting the feed speed is continued,
If Vs < = Vth2: the feeding of the filament is not normal but the compensation is possible in the printer itself, such as adjusting the temperature of the heater nozzle or adjusting the current of the motor,
If Vs > Vth2: If the filament is normally fed, it is checked whether the feeding of the filament is stopped by the command of stopping the printing operation or stopping the filament feeding. If the state is stopped, the filament feeding detecting operation is ended. And if it is determined that the state of the filament is not in the state, the feed detection operation is continued.
The method of claim 3,
After the second step,
If the feed speed Vs is less than or equal to the first error determination reference speed Vth1 (Vs &lt; Vth1), the printer itself performs an error process for impossibility of correction by the printer itself, And then proceeds to detect the feed speed until it becomes larger than the error judgment reference speed (Vth1).
The method of claim 3,
In the third step,
If the feed speed Vs is less than or equal to the second error determination reference speed Vth2 (Vs &lt; Vth2), the filament is not normally fed, but the printer self-compensation process is performed by adjusting the temperature of the heater nozzle, Further comprising: Wherein the method comprises the steps of:
The method of claim 3,
After the third step,
When the feed speed Vs is larger than the second error determination reference speed Vth2 (Vs > Vth2), the feeding operation of the filament proceeds, and it is checked whether or not the feeding of the filament is stopped by the command of printing stop or filament feeding stop If the target speed Vm is not changed, the process returns to the second step and repeats the above step. If the target speed Vm is not changed, the process returns to the first step, Wherein the reference speed is calculated and the operation is repeated.

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