JP6864385B2 - 3D printer, 3D printer module device, and 3D modeling method - Google Patents

Description

The present invention relates to a three-dimensional printer using a fused deposition modeling method, a module device for a three-dimensional printer, and a method for forming a three-dimensional object, and particularly heats a filament-like (linear, rod-like, etc.) modeling material (filament). A 3D printer equipped with a hot end for melting and discharging, a feeding means for supplying the modeling material to the hot end, and a control means for controlling the heating of the hot end, a module device for a 3D printer, and modeling of a three-dimensional modeled object. Regarding the method.

In recent years, it has been actively carried out to manufacture a three-dimensional model by a three-dimensional printer using a computer. The Fused Deposition Modeling Method (FDM) is well known as a major modeling method using such a three-dimensional printer. As a hot end (discharge head) used in this type of three-dimensional printer, for example, one having a structure as shown in FIG. 10 has been proposed (see Patent Document 1). The hot end shown in FIG. 10 has an insulating substrate 101a, a heat generating resistor 101b, and a temperature measurement resistor on the side surface of the flow path structure 100 made of a metal block in which a flow path (passage) of a modeling material is formed. A heating plate 101 composed of a body (not shown) and a cover member 101c is attached. The modeling material supply unit 103 is attached to the flow path structure 100 via the attachment portion 102, and the filament 105 is fed into the flow path of the flow path structure 100 by a feeding means (not shown). The modeling material sent into the flow path is melted by the heat given from the heating plate 101, and the melted modeling material 106 is discharged from the discharge port 104 provided at the tip of the flow path structure 100.

In the hot end used for this FDM, a temperature sensor provided in a heating means such as a temperature measuring resistor provided in the heating plate 101 or a thermista provided in the heat block has a predetermined temperature range set according to the type of filament. When it is detected that the temperature is below the lower limit of, the power supply to the heating means is restarted and heating is started, and when it is detected that the upper limit of the predetermined temperature range is reached, the power supply to the heating means is stopped. The heating temperature is controlled. That is, temperature control is performed such that the heating temperature is maintained in a desired temperature range by turning on / off the power supply to the heating means.

JP-A-2018-66056

However, in the above-mentioned temperature control of the hot end for FDM, during modeling of a three-dimensional model, during an interval with the next model, when confirming the modeling process by observing the three-dimensional model during modeling, etc. When the operation (discharge of the melted modeling material) is temporarily stopped and then the modeling operation is restarted, a situation may occur in which a good modeling operation cannot be performed. That is, if the heat capacity is reduced due to the miniaturization of the hot end body or the heating means, or the filament feed rate is increased in order to increase the stacking speed, for example, the temperature of the heating means approaches the lower limit of the predetermined temperature range. When the filament is fed (pushed) and molding is started at the timing immediately before the power supply is turned on to restart heating, the temperature drops below the lower limit due to heat being taken away by the low temperature filament. It will end up.

When a high-temperature melting material (high-temperature material) that needs to be melted at 300 ° C. or higher is used as the filament, in particular, such as super engineering plastic (for example, PEEK), the effect of lowering this temperature tends to be large, and the flow tends to increase. The viscosity of the modeling material in the road temporarily increases, making it impossible to smoothly feed (push) and discharge the modeling material, interrupting the discharged modeling material, and reducing the adhesion of the discharged modeling material. It can cause it.

The present invention has been made in view of such a situation, and an object of the present invention is that a good modeling operation can be performed even when the modeling operation is intermittently and repeatedly executed in an FDM three-dimensional printer. An object of the present invention is to provide a highly reliable three-dimensional printer, a module device for a three-dimensional printer, and a method for modeling a three-dimensional model.

As a result of intensive research to achieve the above object, the present inventor starts feeding filaments when the paused modeling operation is resumed in the control of the heating means for melting the modeling material at the hot end of the three-dimensional printer. It was found that good modeling operation can be performed by adding the power supply to the heating means in synchronization with the above.

That is, in the present invention, a hot end that heats, melts, and discharges a filament-shaped modeling material, a feeding means for supplying the filament-shaped modeling material to the hot end, and heating of the filament-shaped modeling material. A three-dimensional printer including a control means for controlling the above, wherein the hot end is supplied from a supply unit having a supply port to which the filament-shaped molding material is supplied, and a heating means to which a heating means is attached. melting unit for melting the filamentary shaped material, a discharge section having a discharge port for discharging the molding material is melted by the melting unit, and, communicating the supply port and the discharge port through the melting portion comprising a through passage for said control means, while pausing the supply of the build material by said feeding means, a predetermined amount of said heating means to maintain the molten state of the build material in the melting unit It is possible to execute the control of supplying electric power and the control of supplying the heating means with an amount of electric power larger than the predetermined amount substantially in synchronization with the restart of the supply of the modeling material. The present invention relates to a three-dimensional printer.

In the present invention, it is possible to execute control of supplying electric power larger than a predetermined amount to the heating means substantially in synchronization with restarting the supply of the modeling material. However, in the present invention, "synchronization" means modeling. It means at the same time as the start of supply of the material or a little before the start of supply of the modeling material (prior to the start of supply). That is, by increasing the electric power (W) supplied to the heating means at the same time as or in advance when the supply of the modeling material is restarted, it is attempted to compensate for the decrease in the temperature of the melting part due to the supply of the modeling material in advance or at the same time. To do. It is more preferable to supply the electric power (a larger amount than a predetermined amount) added to the heating means shortly before the start of supply of the modeling material, for example, about 1.0 to 0.3 seconds before. Since the temperature of the melting part (heating temperature) drops when the supply of the modeling material is started (restarted), the viscosity of the molten modeling material in the melting part is required by performing excess heating slightly before the time when the supply of the modeling material is restarted. It is possible to reduce the increase above and to perform smooth discharge.

Further, the present invention controls a hot end that heats and melts and discharges a filament-shaped modeling material, a feeding means for supplying the filament-shaped modeling material to the hot end, and heating of the filament-shaped modeling material. A module device for a three-dimensional printer provided with a control means for the above, wherein the hot end is supplied from a supply unit having a supply port to which the filament-shaped modeling material is supplied, and a heating means to which a heating means is attached. melting unit for melting the filamentary building material that is, a discharge section having a discharge port for discharging the molding material is melted by the melting unit, and the melting portion of the supply port through the and said discharge port comprising a through channel communicating, the control means, during the pauses the supply of the build material by said feeding means, a predetermined amount of said heating means to maintain the molten state of the build material in the melting unit The control for supplying the power of the above and the control for supplying the heating means with an amount of power larger than the predetermined amount in substantially the same time as the feeding means restarts the supply of the modeling material can be executed. The present invention relates to a module device for a three-dimensional printer.

In the three-dimensional printer or the module for a three-dimensional printer of the present invention, the hot end may include a temperature adjusting unit provided so as to surround the hot end between the heating means and the supply unit. By providing the temperature adjusting portion, the filament-shaped modeling material is preheated before reaching the melting portion, and the decrease in temperature of the melting portion when the feeding of the modeling material is resumed can be suppressed. In addition, by providing a temperature control section, an appropriate temperature gradient can be obtained from the lower end (tip) of the hot end to the supply section, and it is possible to prevent the melted modeling material from flowing back to the supply section side more than necessary. The problem of clogging due to the melted molding material resolidifying on the upper side of the hot end can be alleviated.

In the three-dimensional printer or the module for a three-dimensional printer of the present invention, for example, 2 to 4 heating means may be arranged (circumferentially) so as to surround the hot end (melting portion), or hot. A plurality, for example, two or three may be arranged and used in the vertical direction (length direction) of the end, or these may be used in combination. The plurality of heating means may have the same heating area facing the melting portion (same size) or different heating areas (different sizes), and are displaced from each other in the length direction of the hot end. It may be provided at a position.

Further, in the present invention, there are a supply unit having a supply port to which the filament-shaped modeling material is supplied, a melting unit to which a heating means is attached and the filament-shaped modeling material supplied from the supply unit is melted, and the melting unit. A filamentous modeling material is specified at a hot end having a discharge port for discharging the melted modeling material and a passage for communicating the supply port and the discharge port via the melting portion. a molding method for molding a three-dimensional object by supplying at a pitch, Tokoro said heating means to maintain the molten state of the build material in the melting unit when the supply of the building material is suspended A three-dimensional model characterized by having a step of supplying a fixed amount of electric power and a step of supplying an amount of electric power larger than the predetermined amount to the heating means substantially in synchronization with restarting the supply of the modeling material. It relates to the modeling method of.

In the present invention, the "heating means" is not particularly limited, and for example, a known heating plate such as a heating head in which a heat generating resistor is formed on an insulating substrate, a heat block, or the like is used. However, it is more preferable to use a heating head having excellent heat generation response.

According to the present invention, when the molding operation is restarted (started), the amount of electric power supplied to the heating means at the same time as or shortly before the start of feeding the filament-shaped molding material (filament) is the filament feed. Since the amount of electric power supplied to the heating means at the time of pausing is set to be larger than the amount of electric power supplied to the heating means, the heat of the melted portion is newly supplied when the filament is sent to resume the modeling operation after pausing. A module device for a 3D printer or a 3D printer, which can suppress the temperature of the melting part from being momentarily lowered and the viscosity of the modeling material from becoming higher than necessary due to being deprived of the electric power, and can perform a good modeling operation. And a method of modeling a three-dimensional model can be provided. In addition, it is possible to promote miniaturization of the hot end, improve the stacking speed, and reduce power consumption.

When the temperature adjusting unit is used, the filament before being supplied to the melting unit is preheated to some extent, so that the temperature of the melting unit does not drop below a predetermined temperature even if the filament is fed again. Can be further improved. Further, by providing the temperature adjusting portion, an appropriate temperature gradient can be obtained from the lower end portion (tip portion) of the hot end to the supply portion, and the melted modeling material can be prevented from flowing back to the supply portion side more than necessary, resulting in clogging. Therefore, it is possible to provide a more reliable three-dimensional printer, a module device for a three-dimensional printer, and a method for modeling a three-dimensional model.

It is (A) front view and (B) side view of the hot end in the 3D printer of one Embodiment of this invention. It is (A) front view and (B) bottom view of the head body of the hot end in the 3D printer of one Embodiment of this invention. It is a schematic diagram explaining the 3D printer of one Embodiment of this invention. It is a figure explaining the heating plate which is the heating means of the hot end in the 3D printer of one Embodiment of this invention. It is a block diagram explaining the control of heating by a control means. It is a flowchart explaining the control of heating by a control means. It is a side view which shows another example of the hot end in the 3D printer of one Embodiment of this invention. It is a side view which shows still another example of the hot end in the 3D printer of one Embodiment of this invention. It is a side view which shows still another example of the hot end in the 3D printer of one Embodiment of this invention. It is a side view which shows an example of a hot end in a conventional 3D printer.

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 (A) shows a front view of the hot end 10 which is an example of the hot end used in the three-dimensional printer of the present invention, and FIG. 1 (B) shows a side view of the hot end 10. A) shows a front view of the head main body 1, and FIG. 2 (B) shows a bottom view of the head main body 1. The hot end 10 has a supply unit 11 having a filament-shaped modeling material supply port 111, a melting unit 13 for melting the supplied filament-shaped modeling material, and a discharge unit having a discharge port 141 for discharging the melted modeling material. 14. A heat insulating portion 12 between the supply unit 11 and the melting unit 13 that suppresses the heat of the melting unit 13 from being conducted to the supply unit 11, and a passage 2 that communicates the supply port 111 and the discharge port 141. The head body 1 is provided with a heating plate 15 which is a heating means for heating the melting portion 13 and a temperature adjusting portion 16 at or near the boundary portion between the melting portion 13 and the heat insulating portion 12. In the illustrated example, a pair of heating plates 15 are provided so as to be in contact with both facing surfaces of the melting portion 13 of the head body 1 so as to sandwich the head body 1, but the heating plates 15 are provided on only one of them. May be done. In FIG. 1B, the heating plate 15 is drawn with the heat generating resistor 152, the electrode 153 (see FIG. 4), and the lead 150 (see FIG. 1A), which are the components thereof, omitted.

The hot end 10 can be attached to a 3D printer or a module device for a 3D printer via an adapter (not shown). For example, the supply portion 11 of the hot end 10 is inserted into the opening provided in the adapter and can be fixed by a set screw or the like. The adapter is provided with a passage communicating with the supply port 111, and the filament-shaped modeling material is inserted into the flow path (passage) 2 of the hot end 10 through this passage. It is also possible to cut a thread groove on the outer circumference of the supply unit 11 and attach it to the adapter by screwing.

FIG. 3 schematically shows an example of the configuration of a Fused Deposition Modeling (FDM) three-dimensional printer to which the hot end 10 is attached. In FIG. 3, the module device for a three-dimensional printer in the modeling chamber 301 is shown as a schematic perspective view, and the modeling pedestal 3012 rotatable in the xy plane direction is placed on the stage 3011 movable in the z-axis direction. There is. The printer head 3013 has a support shaft 3016 that slidably engages with the y-axis direction rail 3014 and extends in the x-axis direction, and a support that slidably engages with the x-axis direction rail 3015 and extends in the y-axis direction. The shaft 3017 is coupled, and the printer head 3013 is movable in the x-axis and y-axis directions. The hot end 10 is attached to the printer head 3013 via an adapter. The filament fed from the filament reel 304 by the feeding means 305 is supplied to the printer head 3013. The supplied filament is inserted into the flow path of the hot end 10, and the modeling material melted by the heat of the melting portion 13 of the hot end 10 is discharged onto the rotary pedestal 3012 to form a three-dimensional model.

The operation of the printer head 3013, the stage 3011, and the rotary pedestal 3012 is controlled by, for example, the driving means 302, which is a stepping motor, by a control signal from the modeling control means 303. The control of the filament feeding operation of the feeding means 305 is also controlled by the control signal from the modeling control means 303, and the start, stop, and adjustment of the feeding speed of the filament feeding operation are adjusted by the rotation speed of the rollers of the feeding means 305. obtain. The discharge amount of the melted molding material discharged from the hot end 10 is adjusted by controlling the filament feed rate by the feed means 305. In the example 3D printer shown in FIG. 3, the print head 3013 moves in the xy plane and the stage 3011 moves in the z-axis direction (up and down movement), but the print head moves in three dimensions in the xy z direction, for example. It may be a delta type three-dimensional printer. The rotation operation in the xy plane direction may be performed by the stage 3011 together with the vertical operation without providing the modeling pedestal 3012.

As described above, in the modeling operation using the hot end, a situation may occur in which a good modeling operation cannot be performed when the modeling operation is restarted after the discharge of the modeling material is temporarily stopped. As a result of intensive studies on this cause by the present inventor, the temperature in the passage (flow path) in the region where the modeling material is melted decreases and the viscosity of the modeling material temporarily increases when the modeling operation is restarted. Therefore, it has been found that a situation occurs in which it becomes difficult to discharge the modeling material.

As a result of further diligent studies by the present inventor and investigating the cause of the temperature drop in the flow path when the modeling operation is restarted, the filament sent when the modeling operation is restarted is deprived of the heat required for melting. I found that. That is, when the modeling operation is temporarily stopped, referring to FIG. 10, the modeling material in the region heated by the heating plate 101 in the flow path of the flow path structure 100 is maintained in a predetermined temperature range and melted. However, the filament is in a solid state in the flow path on the modeling material supply unit 103 side of the heating plate 101. When the molding operation is restarted (the feeding of the filament is started), the solid filament on the molding material supply unit 103 side of the heating plate 101 is fed to the region where the heating plate 101 is provided, and the filament is fed. The heat of fusion causes a temperature drop in the flow path of the region where the heating plate 101 is provided. This temperature drop can be more pronounced as the size of the hot end becomes smaller due to the smaller heat capacity. Further, when a modeling material having a relatively high melting point such as PEEK is used, the amount of heat required for melting is also large, so that the temperature decrease tends to be more remarkable.

Therefore, as will be described in detail later, when the modeling operation is restarted, the present inventor starts feeding a filament in an amount larger than the amount of power supplied to the heating means performed during the suspension of the modeling operation. It was found that by controlling the heating means to supply the electric power in synchronization with the above, it is possible to prevent a decrease in temperature and avoid a defect in the molding operation. Further, as will be described in detail later, by providing the temperature adjusting unit 16, the solid filament before being sent to the melting unit 13 is preheated by utilizing the residual heat of the melting unit 13. It has been found that the occurrence of defects in modeling operation can be effectively suppressed.

Subsequently, first, the head main body 1 will be described in detail. FIG. 2A shows a front view of the head main body 1, and FIG. 2B shows a bottom view of the head main body 1. The head body 1 may have a supply portion 11, a heat insulating portion 12, a melting portion 13, and a discharge portion 14 integrally formed of a heat-resistant material such as metal or ceramics, or a part or all of the head main body 1. It may be formed independently, or it may be discontinuous, such as interposing another member between any or all of the parts. In the illustrated example, the head body 1 is a columnar metal rod having a total length of, for example, 32 mm and a diameter of, for example, 4 mmφ, made of, for example, 64 titanium (an alloy of titanium mixed with 6% by mass of aluminum and 4% by mass of vanadium). , For example, by cutting.

The head body 1 is formed with a passage (through hole) 2 having a diameter of, for example, 2 mmφ extending in a straight line from the filament supply port 111 on one end side to the discharge port 141 for discharging the melted molding material on the other end side. There is. The sizes of the head body 1 and the passage 2 can be appropriately changed according to the size of the filament.

The supply unit 11 of the head body 1 has, for example, a cylindrical shape (cylindrical shape) having a length of 5 mm and a diameter of 4 mmφ. The supply port 11 has a supply port 111 formed at the tip thereof, and is formed in a tapered shape so that, for example, a 2 mmφ passage 2 extends toward the supply port 111 side in the vicinity of the supply port 111 to, for example, 3 mmφ. The supply unit 11 also serves as a mounting unit for an adapter (not shown) for mounting on a three-dimensional printer.

The heat insulating portion 12 is formed so as to have a higher thermal resistance than the melting portion 13, and in the illustrated example, the heat insulating portion 12 is located between the supply portion 11 and the melting portion 13, and has a length, for example. It has a cylindrical shape (cylindrical shape) with a diameter of 11 mm and a diameter of 3 mmφ. As described above, the heat insulating portion 12 has a diameter of 3 mmφ, and since a passage 2 having a diameter of 2 mmφ penetrating the central portion thereof is formed, the heat insulating portion 12 is a thin portion having a wall thickness of 0.5 mm. Further, in the central portion of the heat insulating portion 12, for example, an opening 121 having a length of 8 mm and a width of 1.8 mm, which can reduce the cross-sectional area of the heat insulating portion 12 and increase its thermal resistance, faces the passage 2. It can be formed in pairs. One or a plurality of openings 121 may be provided in the length direction and / or the width direction of the head body 1, and the size may be appropriately determined. The cross-sectional area can be appropriately determined within the range in which the strength is guaranteed in relation to the thermal resistance.

The melting portion 13 has, for example, a length of 13 mm and a diameter of 4 mmφ. The flat surface side (the front surface side of the paper surface in FIG. 2 (A)) and the back surface side (the back surface side of the paper surface in FIG. 2 (A)) are cut into the melting portion 13, and the two flat surface portions face each other with a distance of, for example, 3 mm. It is formed to do. At the center of the flat surface portion, for example, an opening 131 having a length of 8 mm and a width of 1 mm is formed so as to expose the passage 2. A plurality of openings 131 may be arranged side by side in the length direction. In addition, the surface of the flat surface may be roughened, or the surface of the flat surface may be roughened without forming the opening 131. Further, in the vicinity of the discharge portion 14 of the melting portion 13, the passage 2 is narrowed in a taper shape toward the discharge portion 14, and has a diameter of, for example, about 0.6 mmφ in the discharge portion 14.

The discharge portion 14 has a length of, for example, 3 mm, is cut from the front side and the back side, has a width of, for example, 3 mm, and is tapered toward the discharge port 141 halfway in the length direction of the discharge portion 14. The tip portion on which the discharge port 141 is formed has a diameter of, for example, 1.5 mmφ, and the discharge port 141 has a diameter of, for example, 0.6 mmφ.

As a heating means for heating the melting portion 13 in the hot end 10, for example, a heating plate (heating head) in which a thick film resistor layer is formed on an insulating substrate, a heat block, or the like can be widely used. It is preferable to use a heating plate in terms of responsiveness and size. FIG. 4 shows an example of the structure of the heating plate 15 used for the hot end 10 of the present embodiment. The heating plate 15 attached to the melting portion 13 of the head body 1 is, for example, a rectangular plate-shaped ceramic substrate (insulating substrate) 151 having a thickness of 0.3 mm, a length of 12 mm, and a width of 5 mm, such as alumina or zirconia, and an insulating substrate 151. It has a band-shaped heat-generating resistor 152 formed on the surface of the insulating substrate 151, and an electrode 153 formed on the surface of the insulating substrate 151 so as to connect to both ends of the heat-generating resistor 152. The surface of the heat generating resistor 152 may be coated with, for example, a protective layer (dielectric layer) such as glass containing a filler.

The heating plate 15 is a heat generating resistor obtained by printing, for example, an alloy powder such as Ag, Pd, Pt, etc., a thick film paste containing ruthenium oxide, or the like on an insulating substrate 151 on a predetermined pattern, drying, and firing at a predetermined temperature. 152, the electrode 153 can be formed.

Further, a notch may be formed in the forming portion of the electrode 153 of the insulating substrate 151 in order to improve the connection strength between the electrode 153 and the lead 150 (see FIG. 1A). In the example shown in FIG. 4, two notches are provided for each electrode 153, but the number of notches may be one or three or more. Further, one or a plurality of through holes may be provided instead of the notch portion, or the notch portion and the through hole may be used in combination. That is, the notch and the through hole are provided at a high temperature by increasing the connection area and taking measures such as an anchor effect to obtain mechanical engagement in order to improve the connection strength between the electrode 153 and the lead 150. Even when it is heated or moved two-dimensionally or three-dimensionally, a connection failure does not occur.

In the state where the heating plate 15 is attached to the head body 1, the back surface (the surface of the insulating substrate 151 on which the heat generating resistor 152 is not formed) side of the heating plate 15 is the flat surface portion of the melting portion 13 of the head body 1. , For example, a silver-based thick film paste (Ag containing, for example, glass or Cu) is applied and fired as a bonding material so as to cover the opening 131, and the bonding is performed. At this time, the joining material enters the opening 131 and an anchor effect is obtained, so that the heating member can be firmly joined and attached to the melting portion 13 of the head body 1. Here, a pair of heating plates 15 are arranged to face each other on a flat surface portion provided by grinding so as to face the outer wall surface of the melting portion 13, but even if there is only one heating plate 15. It may be 3 or more. For example, four grinding planes may be provided on the outer periphery of the melting portion, and three to four heating plates 15 may be provided. Further, the size and installation position of the heating plates 15 may be changed in part or all of the surfaces, or the head may be provided. A plurality of heating plates may be arranged side by side in the length direction of the main body 1 or the installation position in the length direction may be changed so that an appropriate temperature gradient is formed by the flat portion of the melting portion 13.

In the present embodiment, the width of the heating plate (5 mm) is slightly wider than the width of the flat surface portion (4 mm) of the melting portion 13 of the head main body 1, and the connecting portion between the heating plate 15 and the lead 150 is connected to the head main body. The heating plate 15 is joined to the head body 1 by protruding outward from one side edge of the flat surface portion of the melting portion 13 of 1.

FIG. 5 shows a drive circuit in the case where the temperature is also measured by the heat generating resistor 152 of the heating plate 15 at the hot end 10 and the temperature is controlled by adjusting the heating by the heat generating resistor 152 according to the measured temperature. It is a block diagram which shows an example. That is, this drive circuit is an example of driving with a DC or AC power supply 154. As the power supply 154, a battery, a commercial power supply, or a commercial power supply is adjusted in voltage and application time by a transformer or the like, and a heat generating resistor is passed through an adjusting unit. It is connected to the body 152.

The temperature of the heating plate 15 can be detected by using the heat generating resistor 152 and changing its resistance value. As shown in FIG. 5, the change in the resistance value of the heat generation resistor 152 can be detected by measuring the voltage across the shunt resistor 155 connected in series with the heat generation resistor 152. When the voltage applied to the heat generating resistor 152 is constant, the change in the resistance value can be known if the change in the current is known. That is, the resistance value of the heat generating resistor 152 has a temperature characteristic that changes depending on the temperature. Therefore, by detecting the temperature characteristic (temperature coefficient) in advance, if the resistance value is known, the temperature of the heat generating resistor 152, that is, the insulating substrate 151 can be known. This temperature detection is performed by a control means. Further, the shunt resistor 155 should have a resistance value as low as possible in order to avoid the influence of heat generation. Further, a resistor having a temperature coefficient as small as possible is preferable, and the current is set to be small in order to avoid heat generation due to the current. In the temperature detection, a temperature measurement resistor is provided in the vicinity of the heat generation resistor 152 of the insulating substrate 151 separately from the temperature measurement resistor 152, and the current is supplied from the measurement power supply connected to the temperature measurement resistor. The temperature of the insulating substrate 151 may be detected by measuring the change in the resistance value derived by measuring the voltage across the temperature measuring resistor. Further, the temperature of the heating plate 15 may be different between the lower end portion and the upper end portion of the insulating substrate 151 due to a temperature gradient generated from the discharge portion 14 side to the heat insulating portion 12 side of the insulating substrate 151. Therefore, the temperature may be measured at a plurality of locations on the insulating substrate 151, and the average thereof may be controlled as the detected temperature. When using a plurality of heating plates, the average temperature of each heating plate may be detected. The average temperature of the entire surface of the flat surface portion, which is the outer wall surface of the melting portion 13, may be detected through the insulating substrate 151. Further, a thermocouple may be welded (fused) to the outer wall surface of the melting portion 13 to measure the temperature gradient, and based on this measured temperature, additional heating may be performed on the low temperature side to change the temperature gradient. , The position of the midpoint of the temperature gradient may be changed.

The control means keeps supplying a predetermined amount of electric power (for example, 10 W) to the heating plate 15 in the standby state in which the modeling operation is temporarily stopped (the state in which the filament (resin) in the melting portion is melted), thereby forming the inside of the melting portion. Maintain the presence of melted filaments in the. On the other hand, during the modeling operation, the temperature of the heat generating resistor 152 is adjusted so as to be maintained within a predetermined temperature range while adjusting the amount of the heating voltage applied to the heat generating resistor 152 according to the detected temperature. To do. That is, the control means is given in advance an upper limit value and a lower limit value for maintaining the temperature of the heat generating resistor 152 within a predetermined temperature range, and when the detected temperature exceeds the upper limit value, the adjusting unit When the signal for lowering the power supply amount for heat generation falls below the lower limit value, a control signal for increasing the power supply amount for heat generation is output to the adjusting unit.

As described above, when the molding operation is paused and then restarted, the control means synchronizes with the start of filament feeding when the molding operation is restarted in order to suppress the temperature drop in the melting portion 13 due to the supply of the filament. Then, a signal for increasing the amount of heat generation power for the heat generation resistor 152 to the power generation unit 152 is increased to a larger amount of power (for example, 13W) than a predetermined amount (for example, 10W) at the time of pause. Communicate to. Specifically, before and after the signal for starting the filament feeding from the molding control means 303 (see FIG. 3), which is a means for controlling the molding operation, is output to the feeding means 305 (see FIG. 3), It is also output to the control means that controls the heating of the heating plate 15, and in response to this signal, the control means tells the adjusting unit a little before (for example, 0.5 seconds) before the start of the filament feeding operation, or at the same time. A signal that increases the amount of power for heat generation (for example, 13 W) is transmitted. That is, during the suspension of the modeling operation, a predetermined amount (for example, 10 W) of electric power is supplied to maintain the filament in the melting portion in a molten state, and when the modeling operation is restarted and the filament feeding is restarted, In synchronization with this, control is performed to increase the amount of power supplied to the heating plate 15 (heat generating resistor 152). The control means for controlling the heating may be included in the modeling control means 303 or may be separately provided, and is omitted in FIG. 3 without being shown. The predetermined amount of electric power at the time of pausing and the amount of electric power additionally supplied at the time of resuming can be appropriately determined according to the type, thickness and feed rate of the filament. In other words, if the amount of power supplied when resuming filament feeding is made larger than the amount of power supplied to the heating means at the time of suspension, the increased amount will cause the low-temperature filament to be newly pushed into the hot end. The amount of heat generated can be supplemented in advance. The temperatures and amounts of electric power shown above and below are examples when a filament made of PEEK having an average diameter of 1.75 mmφ is used and the feed rate is 2 mm / sec.

FIG. 6 shows a flowchart illustrating an example of a control operation synchronized with the start of filament feeding at the time of resuming the modeling operation. First, when the power of the 3D printer main body is turned on (S1), the temperature of the melting portion (heating means) is preheated to, for example, about 430 ° C., and waits for the standby state. Preheating is performed by supplying, for example, 10 W of electric power to the heating means. Further, in the standby state, control is performed to adjust the amount of electric power supplied to the heating means so that the temperature of the melting portion does not exceed, for example, about 450 ° C. Specifically, for example, ON / OFF control of the supply power (10 W) is performed so as to be within a predetermined temperature range of about 400 ° C. to 450 ° C.

After that, when a signal to start modeling is given (S2), the filament is fed after confirming that it is in a standby state or that the temperature of the melting part is within a predetermined temperature range (about 400 ° C. to 450 ° C.). The modeling is started (S3). The amount of power supplied to the heating means is added (for example, + 3W) in synchronization with the start of feeding the filament. Specifically, for example, a modeling start signal and modeling data are sent from the modeling data storage device to the control unit (modeling control means 303) of the 3D printer, and a buffer is interposed between the control unit and the drive signal to be sent to the sending means 302. By doing so, an interval can be provided between the transmission of the start signal and the start of filament feeding, and the time when the filament feeding is actually started and the modeling is started can be known, and the modeling is started ( The additional power (eg, 13W) can be supplied to the heating means shortly before (eg, 0.5 seconds before) the time when the filament feeding is started.

In the subsequent flows (S4 to S8), power supply adjustment control is performed so that the temperature of the heating means (melting portion) is within a predetermined temperature range while the filament is fed during modeling. 3W of the amount of electric power added to the heating means in S3 may be removed and returned to, for example, 10W when a predetermined time has elapsed from the start of the operation to the time before the filament feeding is stopped (paused). .. This is because if the filament feed is stopped and 3 W is added and 13 W of power is continuously supplied, the temperature inside the melting part rises to about 480 ° C, and if the filament is pushed in this state, it goes to the hot end supply part side. This is because there is a risk that the melted resin (filament) will flow back and cause clogging of the passage. Therefore, the upper limit of the predetermined temperature range is exceeded (S4: YES) and the power supply is turned off (S5). Regardless, it is more preferable to return to the power supply (10 W) in the standby state immediately after the start of modeling (after a predetermined time has elapsed).

Next, when it is confirmed that the filament feed has been stopped in S8, it is determined whether or not the stop is a stop of the end of modeling (whether it is a temporary stop) (S9), and the end of modeling (main unit power off). ), The power supply is turned off (S11). When it is determined in S9 that the unit is temporarily stopped (standby state), the power supply adjustment control for maintaining the melting portion within a predetermined temperature range is continued. In this standby state, when the filament feed restart signal is input (S10), the process shifts to the stage prior to S3, and the power supply amount increase control is executed in synchronization with the filament feed restart. That is, when the filament feeding is restarted after the molding operation is temporarily stopped, even if the melting portion is within a predetermined temperature range, 13 W of electric power added to the heating means is supplied and the molding is restarted.

By the above-mentioned control, the filament-like molding material sent to the melting portion 13 by resuming the molding operation is effectively heated, and the temperature drop due to the heat of fusion of the filament at the time of restarting the molding operation described above can be suppressed. As a result, the occurrence of defects in the modeling operation due to the temporary increase in the viscosity of the melted modeling material in the flow path 2 of the melting section 13 is suppressed.

As shown in FIGS. 1A and 1B, the hot end 10 has a temperature adjusting portion 16 provided so as to be in contact with and surround the boundary between the heat insulating portion 12 and the melting portion 13. The temperature adjusting unit 16 can be a means for increasing the heat capacity near the boundary between the heat insulating portion 12 and the melting portion 13, such as a metal block having a predetermined thickness such as aluminum or stainless steel.

As described above, the temperature adjusting unit 16 can effectively suppress the occurrence of defects in the modeling operation when the modeling operation is restarted. That is, the temperature adjusting unit 16 is provided so as to be in contact with and surround the boundary between the heat insulating portion 12 and the melting portion 13 of the head body 1, thereby increasing the heat capacity of the boundary portion between the heat insulating portion 12 and the melting portion 13 and releasing the heat capacity. The amount of heat can be increased, and the temperature gradient from the melting portion 13 to the heat insulating portion 12 is made gentle. The residual heat of the melting portion 13 can preheat the solid filament in the flow path 2 near the boundary. When the modeling operation is temporarily stopped, the filamentous modeling material in the vicinity of the boundary between the heat insulating portion 12 and the melting portion 13, particularly in the flow path 2 on the heat insulating portion 12 side, is preheated to melt when the modeling operation is resumed. Even if it is sent to the portion 13, the amount of heat required for melting the molding material is small, so that the amount of heat taken from the surroundings at the time of melting is reduced as compared with the case where it is not preheated. As a result, the temperature drop of the melting portion 13 when the modeling operation is restarted is further suppressed, and the modeling operation is performed satisfactorily.

Here, the boundary portion between the melting portion 13 and the heat insulating portion 12 or the vicinity of the boundary portion belongs between the melting portion 13 and the heat insulating portion 12 (boundary), or at least one side of the melting portion 13 and the heat insulating portion 12. The portion is included, and it is not necessary to include the boundary between the melting portion 13 and the heat insulating portion 12 at this time. The temperature adjusting unit 16 may be provided at such a position. The size, shape, weight, capacity, etc. of the temperature adjusting unit 16 can be appropriately determined according to the type of the modeling material, the feeding speed of the modeling material during the modeling operation, and the like. For example, specific examples of the shape include a ring shape, a cylindrical shape, and a polygonal columnar shape. When the shape is ring-shaped, the diameter of the outer circumference of the temperature adjusting unit 16 is, for example, 5 mmφ.

Further, as shown in FIG. 7, the heating plate 15 and the heat insulating portion 12 are located in the middle of the heating plate 15 and the heat insulating portion 12 on the outer periphery of the temperature adjusting portion 16 which is a ring-shaped metal block, for example, which is in contact with and surrounds the boundary portion between the heat insulating portion 12 and the melting portion 13. A cover 160 that covers up to the portion may be attached. The cover 160 is preferably made of a material having a good heat emissivity, and for example, copper or stainless steel that has been subjected to an oxidation treatment can be used. The cover 160 is provided so as to block the surrounding area. With such a configuration, the residual heat of the melting portion 13 can be more efficiently used for preheating the filament on the heat insulating portion 12 side. Further, since the radiant heat from the heating plate 15 can be kept in the vicinity of the melting portion 13, the melting portion 13 can be heated more efficiently. A separate preheating means may be provided for preheating the filament, and the filament can be preheated by raising the ambient temperature around the hot end 10.

In the hot end 10 shown in FIGS. 1A and 1B, a pair of heating plates 15 and 15 are attached to both of the pair of cut flat surfaces of the melting portion 13 of the head body 1. The above-mentioned control for controlling the temperature of the melting unit 13 within a predetermined range, the control of stopping the power supply when the upper limit value is exceeded, and the start of the power supply when the temperature falls below the lower limit value, and modeling. The control to start the power supply in synchronization with the start of filament feeding at the time of resuming the operation can be executed by each of the first heating plate 15 on one side and the second heating plate 15 on the other side. However, one of the pair of heating plates 15 and 15 (for example, on the first heating plate) is controlled to keep the temperature within a predetermined range, and the other (for example, on the second heating plate) starts filament feeding. Control may be performed to start the power supply in synchronization with the above.

The temperature measurement is performed by each of the pair of heating plates 15 and 15, and the heating of each heating plate 15 may be controlled based on the detected temperature, but the temperature is measured by one of the heating plates 15. The heating of both the pair of heating plates 15 and 15 may be controlled based on the detected temperature. Further, one heating plate 15 measures only the temperature, and the other heating plate 15 controls the temperature within a predetermined range, and when the molding operation is restarted, the electric power is synchronized with the start of filament feeding. Both temperature controls to start the supply may be performed.

In the example shown in FIG. 1 (B), the pair of heating plates 15 and 15 are drawn to have the same size, and the area in contact with the melting portion 13 (the area of the heating portion) is also drawn to have the same size. The heating plates 15 and 15 may be of different sizes, so that the area of the heating portion in contact with the melting portion 13 of one heating plate 15 and the area of the heating portion in contact with the melting portion 13 of the other heating plate 15 are different. The heating portion in contact with the melting portion 13 may be provided, and the heating portion may be installed by shifting the position of the hot end 10 in the length direction by the pair of heating plates 15 and 15. An example of a hot end 10 provided with a pair of heating plates 15 and 15 having different sizes on one side and the other side is shown in FIG. By making the positions and sizes of the heating portions of the pair of heating plates 15 and 15 different, the heat distribution in the flow path 2 can be appropriately adjusted according to the type, size, and feed rate of the filament.

The heating plate 15 which is the heating means of the hot end 10 may not be provided as a pair of heating plates 15 and 15, but may be provided in contact with only one side of the head main body 1. FIG. 9 shows an example in which a flat surface portion cut on only one side is provided on the melting portion 13 of the head main body 1, and the heating plate 15 is provided in contact with the flat surface portion. In this example, since only one side of the melting portion 13 is cut to form a flat portion, the volume is larger, that is, the heat capacity is formed larger than that in which both sides of the melting portion 13 are cut to provide the flat portion. Therefore, the temperature drop at the time of restarting the above-mentioned modeling operation can be alleviated. In this case, a plurality of heating plates obtained by miniaturizing the heating plates 15 may be attached to the flat surface portion of the melting portion 13.

PEEK (polyetheretherketone) known as a super engineering plastic having a high heat resistant temperature using a three-dimensional printer provided with the hot end of the above-described embodiment, the filament feeding means, and the control means for controlling the heating of the modeling material. It has been confirmed that can be satisfactorily formed by using the filament. The hot end 10 of the above-described embodiment has a length of about 32 mm and a width of about 5 mm as a whole, and is much smaller than the existing hot end. However, the filament feeding is performed after the molding operation is temporarily stopped. The temperature drop in the melting portion 13 when the operation is restarted is suppressed, and the delay in the laminating time is reduced by shortening the time required for heating for lowering the viscosity of the modeling material whose viscosity has temporarily increased. It has been confirmed that the stacking speed is improved, the power consumption is reduced (energy saving), and the three-dimensional model is formed well.

Further, since the hot end of the above-described embodiment can be rapidly heated to a high temperature of 500 ° C., it can also be used for low melting point metals and low melting point glasses as a modeling material.

1 Head body 2 Passage 10 Hot end 11 Supply part 111 Supply port 12 Insulation part 121 Opening part 13 Melting part 131 Opening part 14 Discharge part 141 Discharge port 15 Heating plate 150 Lead 151 Insulation board 152 Heat generation resistor 153 Electrode 154 Power supply 155 Shunt Resistance 16 Temperature control unit 160 Cover 100 Flow path structure 101 Heating plate (heating head)
102 Mounting part 103 Modeling material supply unit 104 Discharge port 105 Filament-like modeling material 106 Melted modeling material 301 Modeling chamber 302 Driving means 303 Modeling control means 304 Filament reel 305 Feeding means 3011 Stage 3012 Modeling pedestal 3013 Printer head 3014 y-axis Directional rail 3015 x Axial direction rail 3016, 3017 Support shaft

Claims (3)

A hot end that heats and melts and discharges filamentous modeling material,
A feeding means for supplying the filament-shaped modeling material to the hot end, and
A three-dimensional printer provided with a control means for controlling the heating of the filament-shaped modeling material.
The hot end
A supply unit having a supply port to which the filament-shaped modeling material is supplied,
A melting part, to which a heating means is attached and which melts the filamentous modeling material supplied from the supply part,
Discharge portion having a discharge port for discharging the molding material is melted by the melting unit, and,
Comprising a through passage communicating with said supply port and said discharge port via said melting unit,
The control means
Control to supply a predetermined amount of electric power to the heating means in order to maintain the molten state of the modeling material in the melting portion while the supply of the modeling material by the feeding means is temporarily stopped, and
A three-dimensional printer characterized in that it is possible to execute a control of supplying electric power in an amount larger than the predetermined amount to the heating means substantially in synchronization with the feeding means restarting the supply of the modeling material. A hot end that heats and melts filamentous modeling material and discharges it,
A feeding means for supplying the filament-shaped modeling material to the hot end, and
A module device for a three-dimensional printer including a control means for controlling heating of the filament-shaped modeling material.
The hot end
A supply unit having a supply port to which the filament-shaped modeling material is supplied,
A melting part, to which a heating means is attached and which melts the filamentous modeling material supplied from the supply part,
Discharge portion having a discharge port for discharging the molding material is melted by the melting unit, and,
Comprising a through passage communicating with said supply port and said discharge port via said melting unit,
The control means
Control to supply a predetermined amount of electric power to the heating means in order to maintain the molten state of the modeling material in the melting portion while the supply of the modeling material by the feeding means is temporarily stopped, and
For a three-dimensional printer, the feeding means can be controlled to supply an electric power larger than a predetermined amount to the heating means substantially in synchronization with restarting the supply of the modeling material. Modular device. A supply unit having a supply port to which the filament-shaped modeling material is supplied, a melting unit to which a heating means is attached to melt the filament-shaped modeling material supplied from the supply unit, and a modeling material melted in the melting unit. A filamentous molding material is supplied at a predetermined pitch to a hot end having a discharge portion having a discharge port for discharging and a passage for communicating the supply port and the discharge port via the melting portion. It is a modeling method for modeling a modeled object,
Providing a power of a predetermined amount of said heating means to maintain the molten state of the build material in the melting unit when the supply of the building material is paused, and resumes supply of the build material A method for forming a three-dimensional object, which comprises a step of supplying electric power in an amount larger than the predetermined amount to the heating means substantially in synchronization with the above.

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