JP6942373B2 - Hot end for 3D modeling equipment, and 3D printer equipped with hot end - Google Patents

Description

The present invention relates to a hot end for a fused deposition modeling method (FFF method or FDM method) three-dimensional modeling apparatus (three-dimensional printer), and a three-dimensional printer equipped with the hot end.

In recent years, it has been actively carried out to manufacture a three-dimensional model by a three-dimensional printer using a computer. As a modeling device for producing such a three-dimensional model, a filament (filament-like modeling material) is sent to a head equipped with a heater for melting the filament, and the molten modeling material is laminated to form the model. A three-dimensional printer of the heat-melting lamination method is known (see, for example, Patent Document 1). In the modeling apparatus disclosed in Patent Document 1, a motor (extruder) having a gear (rotating member) in contact with the filament is arranged between the filament reel and the head, and the filament derived from the filament reel is a motor. Is sent out toward the head by the rotation of. The filament fed to the head is melted by the heat given from the heater that heats the filament, which is a modeling material, and the melted filament is pushed out toward the modeling stage from the discharge port of the nozzle provided at the tip of the head. The head discharges while moving relative to the modeling stage in two directions, and deposits the melted filament on the modeling stage.

In such a three-dimensional printer, the ejection speed of the melted modeling material in the modeling operation is controlled by the speed at which the filament is fed to the head, that is, the rotation speed of the motor. The rotation speed of the motor is controlled to a desired rotation speed by a rotation drive signal given from the control unit.

JP-A-2018-89923

In a three-dimensional printer as shown in Patent Document 1 described above, an extruder (a gear that sends a filament to a head, a motor that rotates the gear, a shaft member that transmits the drive of the motor to the gear, etc.) is transferred from the head to the filament. Since it is located at a remote position on the upstream side, the filament between the extruder and the head may bend or twist as the head moves, making it difficult to feed the filament to the head at an accurate speed. It is thought that it can occur. It is considered that such a situation hinders accurate modeling operation and causes defects in the manufactured model. In addition, since the head and the extruder are attached as separate bodies, the drive portion at the time of modeling has become large.

The present invention has been made in view of such a situation, and is a three-dimensional printer equipped with a highly reliable hot end and a hot end capable of accurately controlling the ejection of a molding material by a filament feeding operation. The purpose is to provide.

As a result of intensive research to achieve the above object, the present inventor has integrated the discharge head and the filament feeding mechanism (extruder) to accurately control the molten molding material by controlling the feeding speed of the filament. It was found that it can be discharged to the machine and the modeled object can be manufactured with high accuracy. In particular, the filament introduced into the passage of the discharge head is fed out by the filament feed rotating member (gear, roller, etc.) in the passage, that is, the extruder is mounted on the hot end, so that the device is compact. By feeding (pushing) the filament at a position relatively close to the melting part or the discharge port, the filament feeding speed and the discharge amount of the melted molding material can be controlled more accurately. Found to get.

That is, the present invention has an introduction port for introducing a filament as a modeling material, a barrel portion for supplying the filament introduced from the introduction port to the downstream side, and the filament supplied from the barrel portion by heating and melting. A discharge head having a melting portion on the downstream side, a discharge portion having a discharge port for discharging the filament melted in the melting portion, and a passage communicating from the introduction port to the discharge port, and the filament. A filament feed mechanism including a filament feed rotation member for feeding to the downstream side and a drive unit for driving the filament feed rotation member, and a holder portion for supporting the upper end portion of the discharge head and the drive portion are provided. It's a hot end for 3D printers
The barrel portion has an opening in which the passage is exposed, the filament feeding rotary member, that the installed by partially enters the opening being adapted Okuridaseru the filament to the downstream It is characterized by.

Further, the present invention has an introduction port for introducing a filament, which is a modeling material, and heats a barrel portion that supplies the filament introduced from the introduction port to the downstream side and the filament supplied from the barrel portion. A discharge head having a melting portion on the downstream side to be melted, a discharge portion having a discharge port for discharging the filament melted in the melting portion, and a passage communicating from the introduction port to the discharge port, and the filament. A filament feed rotation member for feeding the filament to the downstream side, a pressing rotation member that sandwiches the filament between the filament feed rotation member and the filament feed rotation member, and the filament feed rotation member. A hot end for a three-dimensional printer including a filament feed mechanism including a drive unit for driving a member, an upper end portion of the discharge head, and a holder portion for supporting the drive unit, wherein the barrel portion is a hot end. The passage has a pair of exposed openings, the pair of openings are provided so as to face each other, and the filament feed rotating member is partially inserted into one of the pair of openings. The pressing rotating member, which is installed, is characterized in that a part of the pressing rotating member is inserted into the other opening.

The hot end for a three-dimensional printer of the present invention has an introduction port for introducing a filament, which is a modeling material, and supplies the filament introduced from the introduction port to a downstream side, a barrel portion, and the barrel portion. It is provided with a melting portion on the downstream side for heating and melting the filament, a discharge portion having a discharge port for discharging the filament melted at the melting portion, and a passage communicating from the introduction port to the discharge port. A hot end for a three-dimensional printer including a discharge head, a filament feed rotating member for feeding the filament to the downstream side, and a filament feed mechanism including a drive unit for driving the filament feed rotating member. The barrel portion has an opening in which the passage is exposed, and the filament feed rotating member is installed so as to partially enter the opening so that the filament can be fed to the downstream side. By feeding the filament from the barrel portion to the melting portion by the filament feed rotating member, it is possible to prevent the filament melted in the melting portion from flowing back in the passage from the melting portion to the barrel portion side. wherein the ring-like backflow preventing member for being disposed in the passageway.

The hot end for a three-dimensional printer of the present invention has an introduction port for introducing a filament, which is a modeling material, and supplies the filament introduced from the introduction port to a downstream side, a barrel portion, and the barrel portion. It is provided with a melting portion on the downstream side for heating and melting the filament, a discharge portion having a discharge port for discharging the filament melted at the melting portion, and a passage communicating from the introduction port to the discharge port. The discharge head, the filament feed rotating member for feeding the filament to the downstream side, and the pressing rotating member that sandwiches the filament between the filament feed rotating member and the filament feed rotating member. A hot end for a three-dimensional printer comprising a filament feed mechanism comprising, and a drive unit for driving the filament feed rotating member, the barrel portion having a pair of openings exposed to the passage. The pair of openings are provided so as to face each other, the filament feed rotating member is installed so that a part of the filament feed rotating member is inserted into one of the pair of openings, and the pressing rotating member is installed on the other. A part of the filament is arranged in the opening, and the filament is fed from the barrel portion to the melting portion by the filament feed rotating member, so that the filament melted in the melting portion melts in the passage. A ring-shaped backflow prevention member for preventing backflow from the portion to the barrel portion side is arranged in the passage.

The three-dimensional printer of the present invention is characterized by being equipped with the above-mentioned hot end.

According to the present invention, since the filament feed rotating member of the filament feed mechanism is arranged in the opening formed in the barrel portion on the upstream side of the melting portion of the discharge head, the device can be miniaturized. .. Further, since the filament can be fed (pushed) at a position relatively close to the melting portion or the discharging port, the feeding speed of the filament and the discharging amount of the melted modeling material can be controlled more accurately. As a result, it is possible to provide a highly reliable three-dimensional printer with few molding defects, which can accurately control the ejection operation of the melted modeling material by controlling the filament feeding operation by the filament feeding mechanism.

It is a partial cross-sectional view of an example of a hot end of one embodiment of the present invention. It is (A) front view and (B) bottom view of the discharge head used for the hot end of one Embodiment of this invention. It is a side view of the hot end shown in FIG. It is a side view of another example of the hot end of one Embodiment of this invention. It is a partial sectional view of still another example of the hot end of one Embodiment of this invention.

Hereinafter, a hot end for a three-dimensional modeling apparatus (three-dimensional printer) according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partial cross-sectional view of a hot end 1 which is an example of an embodiment of the present invention. The hot end 1 has a discharge head 100 including a barrel portion 10, a melting portion 20, and a discharge portion 30. The barrel portion 10 has an introduction port 11 for introducing the filament 3a in a solid state, which is a filament-like modeling material, into the discharge head 100. The melting portion 20 provided on the downstream side of the filament of the barrel portion 10 (the side opposite to the introduction port 11) heats the filament 3a in the solid state and changes it into the filament 3b in the molten state. A discharge port 31 for discharging the molten filament 3b is provided at the tip of the discharge portion 30 provided on the downstream side of the melting portion 20. Inside the discharge head 100, a passage 12 that communicates from the introduction port 11 to the discharge port 31 is formed.

A three-dimensional printer that supports the discharge head 100 and the filament feed mechanism 40 and has a hot end 1 attached to the upper end of the tip on the upstream side of the filament provided with the introduction port 11 of the barrel portion 10 of the discharge head 100. A holder portion A, which can also serve as a connecting portion of the above, is attached. The holder portion A is fitted to the barrel portion 10 and connected to the discharge head 100.

An opening 10a is formed in the peripheral wall defining the passage 12 of the barrel portion 10. A part of the filament feed roller 41 and the pressing roller 42 constituting the filament feed mechanism 40 has entered the opening 10a formed in the barrel portion 10 and is in contact with the filament 3a. In the illustrated example, a pair of openings 10a and 10a provided opposite to each other across the passage 12 has a feed roller 41 on one side and a pressing roller 42 on the other side, and a part of each is inside the opening 10a. It has entered and is in contact with the filament 3a. The opening 10a formed in the barrel portion 10 can reduce the cross-sectional area of the barrel portion 10 and increase its thermal resistance. The barrel portion 10 functions as a heat insulating portion that suppresses heat transfer from the melting portion 20 to the introduction port 11.

A heating means (heating head) 60 is attached to the melting portion 20 of the hot end 1. The filament in the passage 12 in the melting portion 20 is melted by the heat given from the heating means 60, and melts through the filament 3c in a mixed state of solid and liquid on the downstream side of the boundary between the barrel portion 10 and the melting portion 20. It changes to the filament 3b in the state of being formed. In the example shown in FIG. 1, two heating means 60 are provided so as to sandwich the melting portion 20 of the discharge head 100.

As the heating means 60, for example, a heating head having a thick film resistor layer formed on an insulating substrate, a heat block, or the like can be widely used, but the heating head is used in terms of responsiveness and size. Is preferable. The heating means (heating head) 60 of the illustrated example includes, for example, a rectangular plate-shaped ceramic substrate (insulating substrate) 61 such as alumina or zirconia, and a band-shaped heat generating resistor 62 formed on the surface of the insulating substrate 61. Has. In the example of FIG. 1, another insulating substrate 63 is provided on the opposite side of the heat generating resistor 62 from the insulating substrate 61.

In a state where the heating head 60 is attached to the discharge head 100, the heating head 60 applies the insulating substrate 61 side to the flat surface portion of the melting portion 20 of the discharge head 100, for example, a silver-based thick film paste as a bonding material. It is fired and joined. In the example of FIG. 1, two heating heads 60 are attached so as to sandwich the discharge head 100. For example, when the melting portion 20 of the discharge head 100 has a square columnar shape and has four flat portions, the melting portion 20 is attached. The heating heads 60 may be provided on all flat surfaces, and the hot end 1 may include four heating heads 60. When the heating head 60 is small, it is possible to provide a plurality of heating heads 60 in the length direction in one flat surface portion.

The heating head 60 heats the temperature of the melting portion 20 to a desired temperature by the voltage applied to the heat generating resistor 62. The temperature of the melting portion 20 can be detected, for example, based on the change in the resistance value of the heat generating resistor 62. A temperature monitoring means such as a sensor may be separately provided to detect the temperature of the melting unit 20. The voltage applied to the heat generating resistor 62 is adjusted according to the detected temperature of the melting portion 20, and during the molding operation of forming the modeled object, the temperature distribution in the passage 12 of the melting portion 20 is shaped. The temperature is controlled so that the material is stable in the melted state. Depending on the configuration of the heating head 60, the melting portion 20 may be heated so as to have a temperature gradient. For example, by configuring the heat generating resistor 62 so that the heating temperature on the upstream side of the filament of the melting portion 20 is lower than the heating temperature on the downstream side of the filament of the melting portion 20, the amount of heat transferred to the barrel portion 10 is suppressed. It is possible to suppress softening and melting of the filament in the passage 12 in the barrel portion 10, which may cause clogging of the molding material in the passage 12.

In the passage 12 between the heating means 60 and the introduction port 11, in this case, in the passage 12 at the lower end of the barrel portion 10, the molding material melted by the melting portion 20 by the heating means 60 is on the barrel portion 10 side (introduction). A backflow prevention member 50 is arranged to prevent backflow to the mouth 11 side). In the example shown in FIG. 1, the backflow prevention member 50 is the upper surface of the step portion 21 provided at the inlet (the boundary portion between the barrel portion 10 and the melting portion 20) to which the modeling material of the melting portion 20 inside the passage 12 is supplied. It is provided in contact with. The backflow prevention member 50 is fixed so as to be sandwiched between an annular fixing member (retaining member) 51 having an inner diameter larger than that of the backflow prevention member 50 and a step portion 21.

The diameter of the passage 12 is formed so as to be smaller on the melting portion 20 side than on the barrel portion 10 side at the entrance of the melting portion 20. The backflow prevention member 50 is arranged in contact with the step portion (step portion 21) where the diameter of the passage 12 changes so as not to enter the passage 12 of the melting portion 20. The backflow prevention member 50 is fixed so as to be sandwiched between the retaining member 51 and the step portion 21 of the passage 12, but the backflow prevention member 50 is press-fitted into the passage 12 without the retaining member 51 being provided. It may be fixed by being done.

In the example shown in FIG. 1, the backflow prevention member 50 is formed in a ring shape that can surround, contact, and hold a part of the peripheral edge in the length direction of the filament. The backflow prevention member 50 is preferably formed of an elastic material whose inner diameter can follow fluctuations within the tolerance of the wire diameter of the filament and maintain a state of being closely held. The material used for the backflow prevention member 50 preferably has heat resistance to the temperature at which the filament melts, and a Ni—Ti alloy, which is a superelastic alloy, can be used as an example. The Ni—Ti alloy, which is a superelastic alloy, has a recovery strain of about 8% due to its superelasticity, and can sufficiently follow fluctuations in filament diameter. Further, a resin having heat-resistant elasticity may be used, and for example, a perfluoroelastomer (FFKM) that can maintain the physical characteristics of rubber even at a high temperature of about 300 ° C. can be used. Further, a superplastic alloy having both superelastic properties and superplastic properties can also be used. Superplastic alloys are preferable because they are extremely easy to mold due to their superplastic properties that can be cold-worked at 99.9% or more at room temperature, and are also excellent in workability. An example of a super-elasto-plastic alloy is "Rubber Metal" (registered trademark) manufactured by Toyotsu Material Incorporated, which belongs to a β-titanium alloy.

The shape of the backflow prevention member 50 is formed in a ring shape in which the inside thereof can be adhered to and held by the filament in a solid state. Here, the ring shape means, for example, a spiral shape, a coil shape, a coil spring shape, a tubular shape, a tubular shape, a washer shape (flat washer shape, a countersunk washer shape, a round washer shape), which can surround and hold the outer periphery of the filament. It has a broad meaning including an oring shape and a tapered tubular shape. When a spiral, coil, or coil spring-shaped backflow prevention member 50 is used, the number of turns of the coil is preferably, for example, 2 to 3 turns. In the example shown in FIG. 1, one backflow prevention member 50 is provided in the passage 12, but a plurality of backflow prevention members 50 may be provided. That is, a plurality of ring-shaped members can be stacked and arranged in the passage 12.

A front view of the discharge head 100 used for the hot end 1 shown in FIG. 1 as seen from the side of the surface to which the heating means 60 is attached is shown in FIG. 2 (A), and a bottom view seen from the discharge port 31 side. Is shown in FIG. 2 (B). The discharge head 100 may have a barrel portion 10, a melting portion 20, and a discharge portion 30 integrally formed of, for example, any one of stainless steel, nickel alloy, titanium, titanium alloy, and ceramics. .. The discharge head 100 may be formed by combining independent members, and other members may intervene in any or all of the members. When the discharge head 100 is formed by combining independent members, the thermal conductivity of the material of the member used for the melting portion 20 and the discharge portion 30 is higher than the thermal conductivity of the material of the member used for the barrel portion 10. A high value is preferable from the viewpoint of effectively utilizing the heat of the heating means 60 for melting the modeling material while suppressing heat transfer to the introduction port 11. Further, when the barrel portion 10 and the melting portion 20 (and the discharging portion 30) are made of separate members, the backflow prevention member 50 can be arranged so as to be sandwiched between the barrel portion 10 and the melting portion 20.

The discharge head 100 shown in FIG. 2 is formed by cutting, for example, a columnar metal rod. The total length of the portion of the discharge head 100 shown in FIG. 2 (A) is, for example, 33 mm. The discharge head 100 is formed by using, for example, 64 titanium (an alloy of titanium mixed with 6% by mass of aluminum and 4% by mass of vanadium). In the illustrated example, the barrel portion 10 has a cylindrical shape (cylindrical shape) having a diameter of, for example, 3 mm, and its length is, for example, 17.5 mm. A passage 12 having a diameter of, for example, 2.3 mm is formed in the central portion of the barrel portion 10. The barrel portion 10 is formed so that the thermal resistance is larger than that of the melting portion 20. On the peripheral wall of the barrel portion 10, for example, openings 10a having a length of 6 mm and a width of 1.8 mm, which can reduce the cross-sectional area of the barrel portion 10 and increase its thermal resistance, are formed in pairs facing the passage 12. Has been done. The opening 10a may be provided one or more in the length direction and / or the width direction of the discharge head 100, and the size thereof can be appropriately determined. The width, length, and number of the opening 10a are the feed roller 41 of the filament feed mechanism 40 that enters the opening 10a, and the feed roller 41 of the filament feed mechanism 40, while considering that the heat resistance is increased while maintaining the rigidity of the barrel portion 10. It can be appropriately determined in consideration of the arrangement and size of the pressing roller 42.

In the illustrated example, the melting portion 20 is formed in a square columnar shape having a rectangular cross-sectional shape having a side of 3.2 mm, for example, the corner portion formed on the C surface, and the length thereof is, for example, 12.5 mm. A heating means 60 may be attached to each of the four side surfaces (planar portions) of the square columnar melting portion 20. Depending on the size, number, position, and the like of the heating means 60 attached to the melting portion 20, the melting portion 20 may be formed in a prismatic shape (for example, a triangular pillar or a pentagonal pillar) other than the square pillar. At the center of the melting portion 20, a passage 12 having a diameter of, for example, 1.8 mm is formed so as to communicate with the passage 12 of the barrel portion 10. As described above, the diameter of the passage 12 in the melting portion 20 is formed to be smaller than the diameter of the passage 12 in the barrel portion 10, and backflow is prevented at the boundary between the melting portion 20 and the barrel portion 10 in which the passage diameter changes. A step portion 21 capable of fixing the member 50 is formed. That is, the thickness of the peripheral wall of the passage 12 in the barrel portion 10 is formed thinner than the thickness of the peripheral wall of the passage 12 in the melting portion 20. In addition, openings may be formed on the four side surfaces of the melting portion 20 to expose the passage 12 in order to heat and melt the modeling material inside the melting portion 20 more efficiently. By attaching the heating means 60 so as to close the opening, the modeling material is directly heated by the heating means 60, and the modeling material can be melted more efficiently.

The discharge portion 30 has, for example, a substantially conical shape having a length of 3 mm, and has a shape that tapers from the melting portion 20 toward the tip end portion (discharge port 31) side of the discharge portion 30. The discharge portion 30 is formed to have a diameter of, for example, 3 mm at the boundary with the melting portion 20, and the tip portion where the discharge port 31 is formed is formed to have a diameter of, for example, 1.5 mm, and the discharge port 31 has a diameter of, for example, 0.4 mm. It is formed. The size of each part of the discharge head 100 and the passage 12 described above can be appropriately changed according to the size of the filament and the like.

Next, the filament feeding mechanism 40 will be described in detail with reference to FIGS. 1 and 2. FIG. 3 shows a side view of the hot end 1 shown in FIG. 1 as viewed from the side where the feed roller 41 is provided, that is, from the right side of the paper surface in FIG. The filament feeding mechanism 40 provided in the hot end 1 has a filament feeding roller 41 and a pressing roller 42. The filament feed roller 41 and the pressing roller 42 are arranged so as to come into contact with the filament 3a on the outer periphery thereof. The filament feeding mechanism 40 is configured to feed the filament 3a into the melting portion 20 at a predetermined speed by the rotation of the filament feeding roller 41. A rotational force is applied to the filament feed roller 41 from a drive unit 43, which is a power source for generating a rotational force, through a drive shaft 41a. By controlling the rotation speed of the feed roller 41, the speed of the filament fed to the melting unit 20 is controlled, thereby controlling the discharge speed of the modeling material 3b discharged from the discharge port 31.

The pressing roller 42 is arranged at a position facing the filament feed roller 41 so as to sandwich the filament 3a together with the filament feed roller 41, and urges the filament 3a to the feed roller 41. The pressing roller 42 does not have an independent drive source, and the filament 3a due to the rotation of the feed roller 41 passively rotates in response to the movement of being pushed into the melting portion 20. As a result, as shown by the arrow in FIG. 1, it rotates in the direction opposite to that of the filament feed roller 41. The pressing roller 42 can be urged and pressed by the filament feed roller 41 by being attached to the holder portion A via, for example, a spring and a guide.

In the example shown in FIG. 3, the driving portion 43 of the filament feeding mechanism 40 is supported under the portion protruding from one of the holder portions A of the hot end 1, and is arranged in the vicinity of the barrel portion 10. The drive unit 43 is, for example, a stepping motor (pulse motor) whose rotational operation can be controlled by a pulse signal. When the drive unit 43 is a stepping motor, a drive pulse signal for controlling the discharge of the modeling material is generated by a drive pulse generation circuit (not shown) according to a predetermined modeling program, and a motor coil current is supplied. Input to the driver (not shown). The stepping motor is rotated by the current given by the driver based on the drive pulse signal, and the rotational force is transmitted to the filament feed roller 41 via the drive shaft 41a to feed the filament 3a to the melting portion 20.

In the illustrated example, the drive shaft 41a coincides with the rotation axis of the filament feed roller 41, the rotation direction of the drive shaft 41a coincides with the rotation direction of the filament feed roller 41, and the rotation speed of the drive shaft 41a remains the same as the filament. The structure is such that the rotation speed of the feed roller 41 is set. However, in order to reduce the rotational speed of the drive shaft 41a given by the drive unit 43 and transmit it to the filament feed roller 41, the rotation given from the drive unit 43 to the drive shaft 41a via another additional roller (rotating member). May be transmitted to the filament feed roller 41. For example, a rotating member smaller (smaller in diameter) than the filament feed roller 41 is provided on the outer periphery of the feed roller 41 so as to be in contact with the outer circumference of the feed roller 41, and rotation is directly transmitted from the drive shaft 41a to the small rotating member, and the small rotation is transmitted. The filament feed roller 41 may be rotated by the rotation of the member. Further, the filament feed roller 41 is formed in the shape of an internal gear, and the drive shaft 41a is arranged inside the filament feed roller 41 in the shape of an internal gear, and transmits the rotation given by the drive shaft 41a to the filament feed roller 41. The external tooth gear-shaped rotating member may be attached.

In the illustrated example, the drive unit 43 is supported by a holder portion A that projects perpendicularly to the length direction of the hot end 1, and the filament feeding mechanism 40 and the discharge head 100 are integrated to form the hot end 1. ing. However, it may not be desirable for the hot end 1 to expand in size in the direction perpendicular to its length. When the hot end 1 moves in the modeling operation, the area on the modeling stage where the modeling material can be discharged is limited, which may hinder the modeling. In consideration of such a thing, the drive portion 43 of the filament feed mechanism 40 is attached to the upper portion of the holder portion A with the drive shaft 41a facing the length direction of the hot end, as shown in FIG. May be good. In this case, a bevel gear, a screw gear, a worm gear, or the like may be provided between the drive shaft 41a and the drive shaft 41b in order to transmit the rotation of the drive shaft 41a to the feed roller 41. In the illustrated example, the rotation of the drive shaft 41a is configured to be transmitted to the drive shaft 41b via a bevel gear.

To increase the frictional force with the surface of the filament 3a in order to reliably transmit the rotation of the filament feed roller 41 to the filament 3a on the outer peripheral surfaces of the filament feed roller 41 and the pressing roller 42 in contact with the filament 3a. Appropriate surface treatment can be applied. The outer peripheral shapes of the filament feed roller 41 and the pressing roller 42 in contact with the filament 3a may be gears having gear-like irregularities. For example, the tip (tooth tip) of the convex portion may be formed sharply so as to reliably push out the filament 3a.

The size of the filament feed roller 41 and the pressing roller 42 is set to a size that allows the filament feed roller 41 and the pressing roller 42 to enter the opening 10a of the barrel portion 10 and come into contact with the filament 3a. When the diameter of the barrel portion is 3 mm, the diameter of the passage 12 is 2.3 mm, the diameter of the filament is 1.75 mm, the width of the opening 10a is 1.8 mm, and the length of the opening 10a is 6 mm, the filament feed roller 41, The pressing roller 42 can be formed, for example, to have a diameter of 5 mm and a thickness of 1.5 mm. The filament feed roller 41 and the pressing roller 42 may be formed in different sizes.

The filament feed roller 41 and the pressing roller 42 also have a function of cooling the filament 3a by abutting on the filament 3a. That is, it is possible to prevent the filament 3a from being softened (melted) by the heat transmitted from the melting portion 20, and to prevent the filament from being clogged in the passage 12. Therefore, the filament feed roller 41 and the pressing roller 42 are preferably formed by using a material having high thermal conductivity, and for example, a metal material such as copper, aluminum, or stainless steel can be used. Ceramics having high thermal conductivity, such as aluminum nitride and aluminum oxide, may be used, and resin materials having high thermal conductivity may be used.

The filament feeding mechanism 40 is provided directly above the melting portion 20 and integrated with the hot end 1, and the filament feeding roller 41 and the pressing roller 42 enter into the opening 10a provided in the barrel portion 10 of the discharge head 100. By doing so, it is difficult for the filament to bend or twist between the filament feeding mechanism 40 and the discharge head 100, and the filament can be accurately fed to the melting portion 20 according to a predetermined modeling program. It becomes. That is, the discharge speed of the modeling material from the discharge port 31 can be accurately controlled. Even when modeling is performed using a filament having low rigidity and flexibility, bending and twisting of the filament are suppressed, and a modeled product can be produced satisfactorily.

The filament feed mechanism 40 may include only the filament feed roller 41 without the pressing roller 42. An example in which the filament feed mechanism 40 is composed of only the filament feed roller 41 is shown in FIG. In the hot end 1a shown in FIG. 5, unlike the hot end 1 shown in FIG. 1, the opening 10a of the barrel portion 10 is formed only in one of the passages 12, and abuts the filament 3a in the opening 10a. As described above, the filament feed roller 41 is inserted. The filament 3a is urged by the filament feed roller 41 so as to be pressed against the peripheral wall of the passage 12. Since the roller of the filament feed mechanism 40 is composed of only the filament feed roller 41, the hot end 1a can be miniaturized.

The hot end 1 shown in FIG. 1 and the hot end 1a shown in FIG. 5 include a metal member (metal block) 71 and a case member (cover member) 72 attached to the outer periphery of the discharge head 100. The metal member 71 and the case member 72 are formed by using a metal material such as aluminum or stainless steel, which has a relatively large heat capacity and high thermal conductivity. The metal member 71 is a substantially cylindrical member having a brim-shaped extending portion at the upper portion, and a through hole suitable for the outer shape of the discharge head 100 is provided in the center thereof. The discharge head 100 is inserted through the through hole, and the metal member 71 is attached in contact with the outer periphery of the region where the backflow prevention member 50 of the discharge head 100 is arranged. A mounting hole 71a is formed on the side surface of the metal member 71. The metal member 71 is fixed to the discharge head 100 by a fixing means such as a set screw inserted into the mounting hole 71a. Further, when fixing the metal member 71, a step portion 22 is provided on a part of the outer periphery of the boundary with the barrel portion 10 above the melting portion 20 of the discharge head 100, and the metal member 71 is provided with a step portion 22 slightly protruding below. It is fitted from the supply port 11 side of the upper end of the discharge head 100, and is positioned so that the lower end portion thereof abuts on the upper surface of the step portion 22. The mounting position of the metal member 71 with respect to the discharge head 100 is movable along the length direction of the discharge head 100.

By attaching the metal member 71 near the region where the backflow prevention member 50 of the discharge head 100 is provided, the heat capacity near the boundary between the melting portion 20 and the barrel portion 10 of the discharge head 100 increases, and the temperature in the region increases. Is hard to rise. Further, the heat dissipation effect can be obtained by increasing the surface area of the metal member 71, particularly the brim-shaped portion. Therefore, it is possible to suppress the heat on the downstream side applied from the heating means 60 to the melting portion 20 of the discharge head 100 to melt the filament to the barrel portion 10 on the upstream side, and it is appropriate to reach the introduction port 11 of the barrel portion 10. The temperature can be adjusted. The boundary between the solid portion and the molten portion of the filament shifts to the region where the backflow prevention member 50 is arranged, and the filament in the portion held by the backflow prevention member 50 melts, and the backflow prevention member 50 The risk of impairing the function of preventing the backflow of the filament due to the above is suppressed. That is, the metal member 71 functions as a heat radiating portion that makes it possible to more reliably maintain the state in which the filament in the barrel portion 10 is solid.

The case member 72 has a substantially cylindrical shape, and the upper portion thereof is attached and fixed so as to fit with the outer circumference of the metal member 71. A notch (groove) 72a is formed in the upper part of the case member 72, and the mounting holes 71a formed on the side surface of the metal member 71 described above are aligned with the groove 72a to fix a push screw or the like. By inserting the means into the groove portion 72a and the mounting hole 71a, the case member 72 and the metal member 71 are integrally fixed to the discharge head 100. The case member 72 covers the entire periphery of the melting portion 20 to which the heating means 60 of the discharge head 100 is attached. A hole 72b for projecting the discharge port 31 is provided on the side opposite to the side fitted with the metal member 71 (the discharge portion 30 side).

The case member 72 has a function of reusing the heat transferred from the discharge head 100 to the metal member 71 by refluxing it to the melting portion 20 side. Since the cover member 72 is provided in addition to the metal member 71, the temperature distribution (temperature gradient) in a region having a predetermined width from the vicinity of the inlet of the melting portion 20 to the discharging portion 30 is passed through depending on the type of filament. It is possible to obtain a stable temperature distribution in which 12 clogging is unlikely to occur. Further, the heat dissipation effect due to the surface of the case member 72 can be expected, and the heat on the downstream side applied from the heating means 60 to the melting portion 20 of the discharge head 100 to melt the filament is transferred to the barrel portion 10 on the upstream side. It can be further suppressed, and the temperature can be made more appropriate toward the introduction port 11 of the barrel portion 10. That is, when the case member 72 is attached in addition to the metal member 71, the case member 72 can also function as a heat radiating portion. The space between the case member 72 and the discharge head 100 covered by the case member 72 may be filled with a heat-resistant insulating material such as glass fiber. Since the groove portion 72a formed in the upper portion of the case member 72 has a predetermined length in the vertical direction, the mounting position of the case member 72 with respect to the metal member 71 can be moved in the vertical direction. .. That is, the range covered by the case member 72 can be arbitrarily adjusted depending on the mounting positions of the metal member 71 and the case member 72 with respect to the discharge head 100.

The discharge head 100 described above has a length of about 33 mm as a whole, and may be a hot end 1, 1a in which the holder portion A, the filament feeding mechanism 40, the metal member 71, the heating means 60, and the case member 72 are integrated. It is smaller than the existing hot end. Further, when the discharge head 100 is made of 64 titanium alloy, the weight is extremely reduced in combination with the small size. Therefore, even when the hot ends 1 and 1a are moved to two dimensions or three dimensions to perform modeling, labor saving of driving energy can be achieved.

Although the embodiment of the present invention has been described above, in the present invention, both or one of the filament feed roller 41 and the pressing roller 42 may be gears. Further, although an example in which a stepping motor is used as the drive unit 43 is shown, further miniaturization can be achieved by using a linear actuator instead of the stepping motor. For example, a linear actuator can be used to drive the worm (rotating shaft) of the worm gear and rotate the worm foil corresponding to the filament feed rotating member to feed the filament. By using the linear actuator (driving unit) and the worm gear (rotating member) in this way, the width of the hot end can be reduced and the extruder can be mounted.

1, 1a Hot end 3a Solid filament 3b Melted filament 3c Solid and liquid mixed filament A Holder 10 Barrel (insulation)
10a Opening 11 Introductory port 12 Passage 20 Melting part 21, 22 Steps 30 Discharge part 31 Discharge port 40 Filament feeding mechanism 41 Filament feeding roller 41a, 41b Drive shaft 42 Pushing roller 43 Driving part 50 Backflow prevention member 51 Retaining member 60 Heating means (heating head)
61, 63 Insulated substrate 62 Heat-generating resistor 71 Metal member 71a Mounting hole 72 Case member 72a Groove 72b Hole 100 Discharge head

Claims (3)

A barrel portion having an introduction port for introducing a filament as a modeling material and supplying the filament introduced from the introduction port to the downstream side, and a downstream side of the downstream side for heating and melting the filament supplied from the barrel portion. A discharge head including a melting portion, a discharge portion having a discharge port for discharging the filament melted in the melting portion, and a passage communicating from the introduction port to the discharge port.
A filament feeding mechanism including a filament feeding rotating member for feeding the filament to the downstream side and a driving unit for driving the filament feeding rotating member.
It is a hot end for 3D printers equipped with
The barrel portion has an opening through which the passage is exposed.
The filament feed rotating member is installed so that a part of the filament feed rotating member is inserted into the opening so that the filament can be fed to the downstream side.
By feeding the filament from the barrel portion to the melting portion by the filament feed rotating member, it is possible to prevent the filament melted in the melting portion from flowing back in the passage from the melting portion to the barrel portion side. A hot end for a three-dimensional printer, characterized in that a ring-shaped backflow prevention member for the purpose is arranged in the passage. A barrel portion having an introduction port for introducing a filament as a modeling material and supplying the filament introduced from the introduction port to the downstream side, and a downstream side of the downstream side for heating and melting the filament supplied from the barrel portion. A discharge head including a melting portion, a discharge portion having a discharge port for discharging the filament melted in the melting portion, and a passage communicating from the introduction port to the discharge port.
A filament feed rotating member for feeding the filament to the downstream side, a pressing rotating member that sandwiches the filament with the filament feed rotating member by being arranged so as to face the filament feed rotating member, and the filament. A filament feed mechanism including a drive unit for driving a feed rotation member,
It is a hot end for 3D printers equipped with
The barrel portion has a pair of openings from which the passage is exposed, and the pair of openings are provided so as to face each other.
The filament feed rotating member is installed with a part inserted into one of the pair of openings, and the pressing rotating member is arranged with a part inserted into the other opening.
By feeding the filament from the barrel portion to the melting portion by the filament feed rotating member, it is possible to prevent the filament melted in the melting portion from flowing back in the passage from the melting portion to the barrel portion side. A hot end for a three-dimensional printer, characterized in that a ring-shaped backflow prevention member for the purpose is arranged in the passage. A three-dimensional printer comprising the hot end according to claim 1 or 2.

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