KR102415413B1 - 3D Printer with Double Parallelogram Linkage - Google Patents

Abstract

The present invention relates to a 3D printer utilizing a double parallelogram linkage, and more particularly, to a main frame; a double parallelogram linkage having one end connected to the main frame; a printing module comprising an extruder for supplying a filament, and a hot end that melts the filament supplied from the extruder and discharges it through a nozzle, and is mounted on the other end of the double parallelogram linkage; a driving motor unit provided on the main frame to control nozzle positions of the double parallel program linkage and the printing module; and a sensing unit configured to control the operation of the driving motor unit by sensing a change in current supplied to the driving motor unit when an abnormal load occurs.
That is, the present invention expands the printing area by applying the double parallelogram linkage to the robot arm, can safely protect the device from various risk factors, and utilizes the double parallelogram linkage that can detect the blockage of the filament at an early stage I would like to propose a 3D printer.

Description

3D Printer with Double Parallelogram Linkage

The present invention relates to a 3D printer utilizing a double parallelogram linkage, and more particularly, by applying a double parallelogram linkage to a robot arm, the printing area can be enlarged, and the device can be safely protected from various risk factors, It relates to a 3D printer that can detect clogging of a filament at an early stage.

In the case of the conventional FDM (Fused Deposition Modeling) 3D printing, most of it operates in the concept of a Cartesian coordinate system, so it brings limitations on the base and limits the size of parts that can be made.

Since the development of Stratasis' FDM method in 1991, general-purpose 3D printers on the market require a rectangular space because they are controlled by the Cartesian coordinate system. A larger space is required than the space to be.

To solve this problem, a 3D printer using a robot arm has been introduced. Due to the nature of the 3D printer, which requires the nozzle to be perpendicular to the ground, the posture control is complicated to maintain the nozzle at the tip of the arm vertically, and the robot arm is positioned against the workpiece or other obstacles. There was also a problem in that the price of the equipment increased because an expensive torque sensor was used to detect the collision.

In addition, when the nozzle to which the filament melts and is supplied is clogged in the FDM method, it is not recognized and the printer is damaged frequently. In addition, in the case of a Bodan type printer in which the filament supply part is spaced apart from the nozzle, there is a problem in that there is no emergency stop function for nozzle clogging, so there is a problem in that the printout and the machine are damaged.

KR 10-1641709 B1, 2016.07.29. Figure 1

It uses a robot arm that occupies a small area and operates widely, does not require attitude control of the nozzle part, can detect and stop a collision with an obstacle without a torque sensor, and provides a 3D printer that can detect clogging of the nozzle. for that purpose

A 3D printer using a double parallelogram linkage according to the present invention includes a main frame; a double parallelogram linkage having one end connected to the main frame; a printing module comprising an extruder for supplying a filament, and a hot end that melts the filament supplied from the extruder and discharges it through a nozzle, and is mounted on the other end of the double parallelogram linkage; a driving motor unit provided on the main frame to control nozzle positions of the double parallel program linkage and the printing module; and a sensing unit configured to control the operation of the driving motor unit by sensing a change in current supplied to the driving motor unit when an abnormal load occurs.

The extruder of the printing module according to the present invention includes a pair of supply rollers for supplying the filament, and an encoder for sensing the rotational speed of any one supply roller among the supply rollers is provided, the encoder When the rotation speed of the supply roller sensed by the sensor and the amount of filament supplied from the extruder do not correspond to each other, a nozzle clogging checking unit for stopping the supply of filament by the extruder is further provided.

The double parallelogram linkage according to the present invention is composed of a first link member connected to the main frame and a second link member connected to the first link member and mounted with the printing module, the main frame, the The first link member and the second link member are characterized in that at least one or more gravity compensating members for enabling gravity compensation for the first link member, the second link member, or the printing module are disposed.

The gravity compensating member according to the present invention includes a first tension spring connecting the main frame and the first link member, a second tension spring connecting the first link member and the second link member, and the second It characterized in that it is configured to include a third tension spring for connecting the link member and the printing module.

According to the present invention, the 3D printer uses a robot arm to operate widely while occupying a small area, does not require attitude control of the nozzle part, can detect and stop a collision with an obstacle without a torque sensor, and can prevent clogging of the nozzle There is a perceptible effect.

1 is a schematic diagram showing the form of a 3D printer utilizing the double parallelogram linkage of the present invention;
2 is a schematic diagram showing another form of a 3D printer using the double parallelogram linkage of the present invention;
3 is a schematic diagram showing a printing module according to the present invention;
4 is a schematic diagram showing a nozzle clogging confirmation unit according to the present invention;
5 is a schematic diagram showing a sensing unit according to the present invention.

In order to explain the present invention, the operational advantages of the present invention, and the objects achieved by the practice of the present invention, preferred embodiments of the present invention are exemplified below and will be described with reference to them.

First, the terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention, and the singular expression may include a plural expression unless the context clearly indicates otherwise. In addition, in this application, terms such as "comprise" or "have" are intended to designate that a feature, number, step, operation, component, part, or a combination thereof described in the specification exists, but one or more other It should be understood that this does not preclude the possibility of addition or presence of features or numbers, steps, operations, components, parts, or combinations thereof.

In describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 to 4, the 3D printer using the double parallel program linkage according to the present invention has a main frame 10, a double parallel program linkage 20, a printing module 30, and a drive It is configured to include a motor unit 40 and a sensing unit 50 .

1 and 2, one end of the double parallel program linkage 20 is connected to the main frame 10 according to the present invention, and the other end of the double parallel program linkage 20 has a printing module 30 ) is installed.

The double parallelogram linkage 20 is connected to the main frame 10 and includes a first link member 21 composed of a plurality of links, and a printing module 30 connected to the first link member 21 is mounted. It is composed of a second link member 23 composed of a plurality of links. In this case, a circle drawn on each link of the first and second linkage members in FIG. 1 indicates that each link is rotatably connected to each other. .

Next, as shown in FIGS. 1 to 3 , the printing module 30 according to the present invention melts the extruder 31 for supplying the filament and the filament supplied from the extruder 31 . It is composed of a hot end (33) for discharging through the nozzle (33a).

The extruder 31 of the printing module 30 configured as described above is provided with a pair of supply rollers 31a, and the filament is supplied by being sandwiched between the supply rollers 31a. The filament supplied from the extruder 31 is melted by the heating unit provided in the hot end 33 , and the melted filament is discharged through the nozzle 33a provided at the tip of the hot end 33 .

The printing module 30 provided as described above is connected to the end of the second link member 23 of the double parallel program linkage 20 , and the control unit operates each link member of the double parallel program linkage 20 . will control In this way, the control of the double parallel program linkage 20 can eventually perform a desired printing operation by controlling the nozzle 33a of the printing module 30 . In this case, the nozzle 33a at the tip of the double parallelogram linkage 20 is maintained perpendicular to the ground according to the linkage characteristics.

In this process, if the supply of the filament supplied from the extruder 31 is not smooth, for example, the nozzle 33a is clogged and the filament cannot advance from the extruder 31, or the extruder 31 If a problem such as the filament being caught in the roller occurs, the extruder 31 may be overheated or the extruder 31 may be damaged.

Therefore, in the present invention, the encoder 61 is mounted on the rotating shaft of any one of the supply rollers 31a of the extruder 31 (the right roller in the figure in FIG. 4), and the encoder 61 supplies A nozzle clogging check unit 60 for detecting the rotational speed of the roller 31a and stopping the operation of the extruder 31 when the rotational speed of the supply roller 31a and the supply amount of the filament do not correspond to each other is provided can be

In this case, as shown in FIGS. 3 and 4 , the encoder 61 of the nozzle clogging check unit 60 may be mounted on the supply roller 31a to which the motor is connected, and the remaining supply rollers 31a (shown in FIG. 4 ). In the left roller) may be configured to be supported by the other supply roller (31a) side by providing an elastic force so that the filament is sandwiched between the supply roller (31a).

The nozzle clogging check unit 60 configured in this way reduces the rotation speed of the supply roller 31a sensed by the encoder 61 when the nozzle 33a is blocked, or a filament is caught between the supply rollers due to abnormality of the rollers. Alternatively, when the supply amount of the filament corresponding to the rotation speed sensed by the supply roller 31a does not correspond, the driving of the extruder 31 is stopped.

Therefore, the nozzle clogging check unit 60 can protect the device by stopping the operation of the extruder 31 when the supply of the filament by the extruder 31 is not smoothly performed due to the above reasons. This means that by enabling automatic control when a remote worker is located, more stable operation of the device can be made possible.

At this time, the control unit commands to stop the supply of the filament by the extruder 31, and accordingly, it is possible to prevent damage to the workpiece or the printer due to the excessive supply of the filament.

In this case, as shown in (a) of FIG. 4 , the communication line 63 is connected to the extruder 31 of the printing module, so that when a transfer failure is detected, a remote operator or manager stops the operation of the printing module, Alternatively, it is also possible to take measures such as turning off the system by controlling the control unit.

On the other hand, since the double parallelogram linkage 20 according to the present invention is formed in a cantilever shape from the main frame 10 to the printing module 30, when the printing module 30 moves away from the main frame 10, the printing module (30) will cause sagging.

In order to prevent this, the first link member 21 and the second link member 23 of the main frame 10 and the double parallel gram linkage 20 include the first link member 21 and the second link member 23 . ) or it is preferable that at least one gravity compensation member 70 that enables gravity compensation for the printing module 30 is disposed.

Such a gravity compensating member 70 may collide with a workpiece or surrounding objects due to various postures of the linkage in the form of a robot arm as shown in FIG. 2, and the printer may no longer operate due to such a collision .

In addition, in the case of the step motor according to the present invention, precise control is possible, but since the torque output is not large, the first link member 21 , the second link member 23 or the printing module 30, which is a heavy body, stops or , a large torque is applied during acceleration and deceleration due to inertial load when starting the operation. When the inertial load increases, a stepper motor with low output may be damaged due to the torque load.

Therefore, by introducing the gravity compensating member 70, this inertial load is reduced to reduce the load on the step motor to prevent failure, and eventually, the link member or the printing module 30 can be prevented from sagging to ensure stable operation of the device. have.

To this end, the gravity compensating member 70 includes a first tension spring 71 connecting the main frame 10 and the first link member 21 , and a first link member 21 and a second link member 23 . It may be implemented by the second tension spring 73 connecting the , and the third tension spring 75 connecting the second link member 23 and the printing module 30 . However, the first tension spring 71 to the third tension spring 75 as the gravity compensating member 70 may be selectively disposed.

That is, the first tension spring 71 is in charge of compensating for the inertial load of the first link member 21 with respect to the main frame 10 , and the second tension spring 73 is applied to the first link member 21 . The second link member 23 is responsible for compensating for the inertial load, and the third tension spring 75 is responsible for compensating for the inertial load of the print module.

In particular, in the case of a Bowden-type 3D printer having a structure in which the extruder 31 of the printing module 30 is directly connected, the weight of the printing module 30 itself is large. could be more effective.

However, various structures may be applied to the gravity compensating member 70 according to the present invention, and such a structure may be a tension spring as in the embodiment according to the present invention, or a piston generating a traction force adjustable by the control unit, etc. can be

In the present invention, as shown in FIG. 5 , a sensing unit 50 is provided for current control of the driving motor unit 40 used for driving the double parallelogram linkage 20 , and the sensing unit 50 is It is configured to automatically turn off the entire system by detecting an abnormal current when a load occurs.

The driving motor unit 40 according to the present invention uses a step motor for precise control. In the case of the step motor, the current strength changes whenever the motor rotates. However, when an abnormal load occurs in the double parallel program linkage 20, the printing module 30, etc., an abnormal current having a wavelength different from the normal current wavelength may be supplied to the step motor. When such abnormal current is supplied to the stepper motor, it may cause heat generation or damage due to overload of the motor, and may act as a cause of equipment damage.

Therefore, in the present invention, when an abnormal load occurs, a current sensor 61 for detecting an abnormal current supplied to the step motor is introduced, and the current sensor 61 detects an abnormal current supplied to the step motor to automatically automatically control the system. By turning it off, the abnormal current cuts off the supply to the stepper motor.

This is because an abnormal load occurs in situations such as when the 3D printer is driven, there is a worker in a remote location, or is absent, and an abnormal current is supplied to the stepper motor by this load, resulting in a fire hazard due to heat of the motor, or damage to the motor , or the device itself may be damaged. In contrast, in the present invention, when an abnormal load is generated and an abnormal current is supplied in the situation as described above, the current sensor 61 detects this in advance and automatically turns off the system itself, thereby solving the above problem.

The above description is merely illustrative of the technical spirit of the present invention, and various modifications and variations will be possible without departing from the essential characteristics of the present invention by those skilled in the art to which the present invention pertains.

Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

10 : mainframe
20: Double Parallelogram Linkage
21: first link member 23: second link member
30: printing module
31: extruder 31a: supply roller
33: hot end 33a: nozzle
35: filament
40: drive motor unit
50: sensing unit
51: current sensor
60: nozzle clogging confirmation unit
61: encoder 63: communication line
70: gravity compensating member
71: first tension spring 73: second tension spring
75: third tension spring

Claims (4)

mainframe 10;
a double parallel program linkage 20 having one end connected to the main frame 10;
It consists of an extruder 31 for supplying a filament, and a hot end 33 that melts the filament supplied from the extruder 31 and discharges it through a nozzle 33a. a printing module 30 mounted on the other end side of the gram linkage 20;
a driving motor unit 40 provided in the main frame 10 to control the positions of the double parallel program linkage 20 and the nozzles 33a of the printing module 30; and
When an abnormal load occurs, a sensing unit 50 for controlling the operation of the driving motor unit 40 by sensing a change in current supplied to the driving motor unit 40;
The double parallel program linkage 20 includes a first link member 21 connected to the main frame 10 and a second link member 21 connected to the first link member 21 to which the printing module 30 is mounted. Consists of a link member (23),
A first tension spring 71 connecting the main frame 10 and the first link member 21, and a second tension spring connecting the first link member 21 and the second link member 23 Double parallel, characterized in that it further comprises a gravity compensating member (70) comprising a spring (73) and a third tension spring (75) connecting the second link member (23) and the printing module (30). 3D printer using program linkage.
The method of claim 1,
The extruder 31 of the printing module 30 includes a pair of supply rollers 31a for supplying the filament, and the rotational speed of any one supply roller 31a among the supply rollers 31a. An encoder 61 is provided for detecting
A nozzle for stopping the filament supply by the extruder 31 when the rotation speed of the supply roller 31a sensed by the encoder 61 and the filament supply amount from the extruder 31 do not correspond to each other 3D printer using a double parallelogram linkage, characterized in that the clogging check unit 60 is further provided.
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