PRINTHEAD DISPENSING DEPOSITION MATERIAL AND METHOD OF FORMING PRINTED OBJECT
A building material discharge head is provided which uses a flow path structure which can be produced with extremely low-cost materials such as plates, etc., and which can discharge, in a prescribed place, a prescribed amount of a building material, even one with a high viscosity. This building material discharge head is provided with, a first heating plate which configures a first lateral wall, which is a part of the lateral wall forming the flow path through which the material flows and which heats the material inside of the path, a closing plate which configures a second lateral wall, which is the part of the lateral wall other than the first lateral wall, a discharge opening which is formed at one end of the path and communicates with the path, and a material supply opening which is formed at the other end of the path and communicates with the path.
This application is the National Stage of International Application No. PCT/JP2015/079183, having an International Filing Date of 15 Oct. 2015, which designated the United States of America, and which International Application was published under PCT Article 21(2) as WO Publication No. 2016/185626 A1, and which claims priority from and the benefit of Japanese Application No. 2015-127059, filed on 24 Jun. 2015 and Japanese Application No. 2015-102185, filed on 19 May 2015, the disclosures of which are incorporated herein by reference in their entireties.
TECHNICAL FIELDThe present invention relates to a printhead dispensing deposition material for discharging (dispensing) a deposition material in the case where a three-dimensional fabricated (formed) object is manufactured with a 3D printer and a fabrication (forming) method for three-dimensional fabrication. More specifically, the present invention relates to a printhead dispensing deposition material which can be manufactured at low cost and assures easy control of discharging of the deposition material and a method of forming.
BACKGROUND ARTIn recent years, manufacturing a three-dimensional fabricated object with a 3D printer using a computer has become popular. In such 3D printers, a three-dimensional model is expressed as a collection of sectional shapes. Thus, a 3D printer discharges a deposition material to a predetermined spot by three-dimensionally moving a nozzle which discharges a deposition material or by moving a table for the fabricated object in order to form a fabricated object. One example of materials for forming such fabricated object includes materials which are formed into a melted state by increasing its temperature such as thermoplastic resins and metals having a low melting point. Also, a photofabrication method, in which a light curing resin (such as ultraviolet-curing resin) is selectively cured by lighting, and an inkjet method, in which a light curing resin, a thermoplastic resin, a wax, and the like are discharged from an inkjet nozzle for laminate fabrication, are known. Also, a reaction type curing method, in which a base resin is discharged and subsequently a curative agent is discharged, is known. The above-mentioned thermally melting material is discharged to a predetermined spot by means of computer control, is solidified as the temperature drops, and a solid body is formed. Therefore, a three-dimensional fabricated object can be obtained by moving this discharge nozzle relatively in a three-dimensional space to discharge a deposition material.
As a device discharging such deposition material, for example, one having a configuration as shown in
On the other hand, in the inkjet method which is mainly used to form a two-dimensional image, ink drops (droplets) are discharged from a plurality of nozzles to perform image formation on a predetermined recording medium. In this recording head, pressure variation is caused by a piezoelectric device in a pressure chamber communicating with a nozzle by an actuator so that an ink droplet is discharged from a nozzle opening. Also, a method of thermal inkjet is known, in which a heater (a heating element) is disposed at the bottom of a nozzle, local heating by the heater causes bubbling of ink, the ink is boiled due to bubble coalescence thereof, and then the ink is discharged (see pages 7 to 9, and 35 of Non Patent Document 2).
PRIOR ART DOCUMENT Non Patent Document
- Non-Patent Document 1: “Digital Art of Design and Manufacturing by 3D Printer” (written by Kazuo Kadota, issued by NIKKAN KOGYO SHIMBUN, LTD., 103 Pages)
- Non-Patent Document 2: “Ink Jet” (issued by The Imaging Society of Japan on Sep. 10, 2008)
As mentioned above, in the configuration where the cylindrical nozzle 61 and the barrel 62 are manufactured and fixed to the heater block 63, there is a problem with increase in material cost and manufacturing cost. In addition, one through-hole needs to be provided and a screw hole needs to be made in each heater block 63, and thus there is also a problem that the entire body of the discharge device including the heater blocks becomes large. Furthermore, because the deposition material is heated from the outside of the heater block 63 by a heater, the heating is indirect and the heat efficiency is not good.
In addition, as shown in
Also, in the above-mentioned method employing an ink jet piezo-electric element, a deposition material is not discharged continuously but is discharged for each of small areas. However, this method employing the piezo-electric element can be applied only to a deposition material having a relatively low viscosity. Also, a pressure variation (a volume variation) by the piezo-electric element is small, and a large amount of a deposition material cannot be discharged at a time. Therefore, a large amount of the discharged deposition material cannot be stacked up. As a result, the method can manufacture a small fabricated (formed) object; however, it is not good at fabricating a large fabricated object. Also, in a thermal system, in which a heater is arranged, a deposition material having a high viscosity such as one which is a fluid but not a liquid cannot be boiled. In other words, there is a problem that the thermal system cannot be applied to a high-viscosity deposition material. Therefore, as mentioned above, a method, in which a deposition material is continuously discharged from a nozzle, has been used generally. A fabricated object cannot be manufactured by discharging a high-viscosity deposition material in an amount needed for each specific spot while relatively scanning either a nozzle or a fabrication (forming) table. As a result, there is a problem that a large fabricated object cannot be manufactured in a short time.
Thus, there is a problem that a high-viscosity deposition material cannot be constantly discharged by a predetermined amount. Consequently, it takes time to manufacture a large-size fabricated object, and a large-sized fabricated object is expected to be manufactured in a short time.
The present invention has been made to solve these problems and an object thereof is to provide a printhead having an improved thermal efficiency, wherein at least a part of a flow path for a deposition material is formed by a part of a heating plate so that the deposition material is heated directly by the heating plate.
Other object of the present invention is to provide a printhead dispensing deposition material having a flow path structure body which can be manufactured easily without using a cylindrical, thread-cut, and thus expensive nozzle but with low-cost materials such as a plate material, and a method of forming therewith.
Another object of the present invention is to solve a problem that the melted deposition material at the discharge opening becomes more viscous and is less fluidized or is solidified and thus unable to be discharged, by allowing the temperature of a flow path, in which a deposition material is melted and flowed, to be higher at a discharge opening side than that at a deposition material supply opening side.
Another object of the present invention is to provide a printhead dispensing deposition material having a configuration which allows a discharge part to be dismantled so that a solidified deposition material can be removed in the case where the deposition material is one which is solidified after once being melted and is unable to be re-melted by elevating a temperature thereof.
Another object of the present invention is to provide a printhead dispensing deposition material having a discharge configuration in which even a high-viscosity material such as one which is a fluid but not a liquid can be discharged to a predetermined spot in a predetermined amount and a fabricated object can be manufactured in a short time while scanning either a discharge opening or a fabrication table.
Another object of the present invention is to provide a printhead dispensing deposition material and a method of forming of a three-dimensional fabricated object, in which discharge openings are formed in line and/or in a plurality of rows so that even a fabricated object comprising materials with different colors and materials with different melting points or the like can be formed in the same layer by a single scan and at the same time a fabricated object of multiple layers can be manufactured by a single scan.
Another object of the present invention is to provide a printhead dispensing deposition material and a method of forming in which, when any of a melting deposition material, an ultraviolet-curable deposition material, or a two-liquid mixing resin material of a base resin and a curing agent is used for fabrication or when those types are used together for fabrication, a fabricated object can be reliably manufactured by continuously discharging different resins at the same spot.
Means to Solve the ProblemThe printhead dispensing deposition material for three-dimensional fabrication of the present invention comprises a first heating plate constituting a first side wall portion being a part of a side wall of a flow path for flowing a deposition material, and heating the deposition material in the flow path; a closing plate or a second heating plate constituting a second side wall portion, the second side wall portion being a part of the side wall of the flow path other than the first side wall portion; a discharge opening communicating with the flow paths and formed on one tip of the flow path; and a material supply opening communicating with the flow path and formed on the other tip of the flow path.
Here, the first side wall portion and the second side wall portion respectively indicate portions of the side wall constituting the flow paths, and do not necessarily indicate, for example, one or two sides of a rectangular shape and mean a part of a peripheral wall, such as a part of an arch of a circular shape. The peripheral wall may be constituted of the first side wall portion and the second side wall portion, and may also be composed of those portions and a third side wall portion.
In one embodiment, the printhead dispensing deposition material further includes a flow path structure body, the flow path structure body comprising a plurality of plates having a through-hole of almost the same shape respectively, and the plurality of plates being bonded together so as to form a third side wall portion with peripheral walls of the through-holes, the third side wall portion being a part of the side wall of the flow paths other than the first side wall portion and the second side wall portion, wherein one end side of the through-hole is closed by the first heating plate; and another end side of the through-hole is closed by the closing plate or the second heating plate, thereby the flow path being formed.
In another embodiment, a groove having a concave sectional shape is formed at a portion of the first heating plate, and the closing plate or the second heating plate is provided to close an opening of the concave groove so that the flow path are formed.
The printhead dispensing deposition material can have a configuration, wherein the closing plate is formed by a thin plate, a third heating plate is further provided on a side opposite to the flow path based on the thin plate, the third heating plate applying a heating effect on the deposition material in the flow path, and the deposition material in the flow path is discharged (dispensed) by instantaneous heating of the third heating plate.
The method of forming of a three-dimensional fabricated object of the present invention comprises, forming one side wall of flow path for discharging (dispensing) deposition material with a thin plate, arranging a third heating plate on the side opposite to the flow path based on the thin plate, and fabricating (forming) a fabricated object while discharging a deposition material of a specific flow path by applying an instantaneous heating effect only to the specific flow path with the third heating plate.
Another embodiment of the method of forming of a three-dimensional fabricated object of the present invention comprises, arranging a plurality of printheads dispensing deposition material having rows of discharge openings respectively, so as to be aligned with the rows of discharge openings in a same direction and a discharging direction of the discharge openings is in a direction intersecting with a fabrication (forming) table, and so as to be different in vertical heights of rows of the discharge openings in at least two rows of the plurality of rows; and forming at least two layers of a fabricated object by a single scan in the x-y direction of the fabrication table provided below the rows of the printheads. Here, the expression of the direction of a discharge direction from the discharge openings intersecting with a fabrication table includes not only the discharge direction from the discharge openings perpendicular to the fabrication table (a table on which a fabricated object is formed) but also ones inclined to it.
Effects of the InventionAccording to the printhead of the present invention, because a part of the side wall of the flow path for the deposition material is formed by a part of the heating plate, the deposition material is directly heated by the heat of the heating plate. As a result, thermal efficiency is considerably increased.
Also, the flow path structure body is formed by plates, a low-cost plate material is used and, in addition, formation of the flow path structure body is very easy; therefore, cost reduction is attained. In addition, manufacturing is very easy because the flow path is formed by the through-hole and the discharge opening is formed by a recess on the plate.
In addition, the third heating plate is provided on a part of a side wall of the flow path with a thin plate interposed to apply a heating effect only to a specific flow path so that the deposition material can be discharged only from the specific flow path with a simple configuration.
Also, the discharge openings are provided in a plurality of rows and are arranged in different heights in the vertical direction in the plurality of rows so that a plurality of layers can be accumulated by a single scan. Therefore, even a large-size fabricated object can be manufactured in a short time.
Next, by referring to the figures, the printhead dispensing deposition material of the present invention and the method of forming therewith are described.
In an example of one embodiment, as shown in
Also, in other embodiment, as shown in
In the flow path structure body 1 in an example shown in
The plates 10 are formed from a material excellent in heat conductivity and easy to be processed to have the through-hole 17 and the recesses. Taking this into consideration, a thin metal plate is preferable. As one example, the plate 10 shown in
Furthermore, the plate thickness is also not limited to the above example, and the plates having various thicknesses can be used in accordance with its intended use. Also, the number of the plates 10 to be put together is not limited to three and can be increased more. When the number of plates is increased, a number of discharge openings connecting with the same flow path 12 can be formed. A printhead dispensing deposition material which can vary its discharging amount can be obtained. Specifically, the discharge opening 13 is formed by forming a recess communicating with the through-holes 12 on at least one of a plurality of the plates of the flow path structure body 1. It should be noted that one of the plates is illustrated in
The discharge opening 13 is formed, for example, by half etching. Specifically, the discharge opening is formed by forming a resist mask on a part where the discharge openings 13 are not formed, and then dipping in an etching solution or spray-etching for spraying an etching solution. Electrolytic etching can also be performed. A depth of etching is controlled according to a time period of exposure to the etchant. In the case of too deep etching, the mechanical strength is reduced, and therefore, the depth of etching is preferably about a half of the thickness of the plate 10 or less. When the plates 10 are thin and a large discharge opening 13 cannot be formed, for example, as shown in the discharge openings 13c, 13d of
For example, three plates 10a, 10b, 10c in which the through-holes (the flow paths 12) and the recesses (the discharge openings 13) are formed are put and bonded together, for example, with a heat resistant adhesive or the like. Then, at the grooves 15 (see
As shown in
When the first heating plate 2 is bonded to this flow path structure body 1, they may be adhered, for example, with a heat resistant adhesive, however, an adhesive which allows easy detachment is preferable. The bonding also may be conducted by screwing and the like. By bonding detachably, disassembling and cleaning can be carried out when the deposition material becomes hardened in the flow path 12. As a result, maintenance becomes easy.
On the other side of the flow path structure body 1, the closing plate 7 is bonded so as to close openings of the through-holes constituting the flow paths 12 as the first heating plate 2 does. The second side wall portion 122 (see
The above-mentioned folded attaching portion 16 of the flow path structure body 1 is fixed to the attaching plate 5. As a result, the printhead dispensing deposition material as shown in
Now, the first heating plate 2 is described in detail. In
This first heating plate 2 has a configuration similar to a conventional heating head used for recording and erasing data on a card or others, in which the heating elements 22, and the temperature measurement resistor 24 are provided on one surface of the insulating substrate 21 with an insulating glaze layer consisting of glass or the like interposed therebetween. However, in the present invention, as shown in
With the second heating element 22b formed as shown in
When the building material at a portion near the discharge openings is away from a heater and its temperature drops, the viscosity thereof is increased and the building material is solidified and thus clogging is likely to occur. However, in this embodiment, as shown above, when a temperature gradient is formed in the insulating substrate 21 and the temperature is higher on the side of the discharge openings 13, the temperature of the building material at the portion near the discharge openings is high and the building material can be discharged with excellent fluidity. In other words, in a conventional heater block in which the temperature is constant throughout the entire body, the temperature of the entire body of the heater block needs to be raised in order to prevent the temperature of the heater block at the discharge openings side from dropping. However, when the temperature of the central part of the heater block becomes too high, deposition material begins to be decomposed or evaporated, which results in carbonization. Therefore, the heater block should not be heated to a high temperature. As mentioned above, by improving the fluidity, the deposition materials are discharged with a small pressure even when the size of the discharge openings 13 is smaller.
For the insulating substrate 21, an insulating substrate having an excellent thermal conductivity and comprising alumina or the like is used. Regarding the shape and dimension thereof, as more discharge openings 13 are needed in accordance with an intended fabricated (formed) object, the flow path structure body 1 becomes larger and accordingly the first heating plate 2, and thus the insulating substrate 21 also become larger. Therefore, the insulating substrate 21 having a size required for a purpose is used, and for example, in the above mentioned example of the flow path structure body 1, an alumina substrate having a size of about 10 mm square, and a thickness of about 0.6 mm is used for two flow paths 12. It is a matter of course that a plurality of the first heating plates 2 may be provided to one flow path structure body 1. Its external shape is also not limited to a rectangular shape and is shaped in accordance with a required shape of the flow path structure body 1. Thus, when twelve flow paths 12 are formed, as mentioned above, the first heating plate 2 (10 mm×60 mm) has a size of six first heating plates 2 each being 10 mm square (three of
The cover substrate 26 which will be described below is formed to protect the heating elements 22 and others formed on the insulating substrate 21, at the same time, to increase a heat capacity of the insulating substrate 21, and, moreover, to prevent warping of the insulating substrate 21 due to the difference between the thermal expansion coefficients. Therefore, though thermal conductivity is not required so much, an alumina substrate having the same thickness as the insulating substrate 21 is used. This cover substrate 26 is not in contact with the flow path structure body 1 and therefore, it is preferable that its thermal conductivity is low. Thus a material having an even lower thermal conductivity can be used. However, when a thermal insulating sheet is affixed to a surface of this cover substrate 26, the same material (a material having the same thermal expansion coefficient) as that of the insulating substrate 21 can be used. Also, the printhead dispensing deposition material is usually configured so that its maximum operating temperature is 150° C., 250° C., 500° C., or the like and a heating temperature is set to a temperature required for an intended purpose.
The heating elements 22 are optimally adjusted in its temperature coefficient, resistance value, and the like by suitably selecting and mixing powders of Ag, Pd, RuO2, Pt, a metallic oxide, glass, and the like. This mixed material is made into a paste, applied, and baked. By this process, the heating elements 22 are formed. A sheet resistance of a resistive film formed by the baking can be changed by an amount of solid insulating powder. The resistance value and the temperature coefficient can be changed by a ratio of the both. Also, for a material used as conductors (electrodes 23, 25, and coupling conductors 27a-27d), a material in a similar paste form in which the proportion of Ag is increased, and the proportion of Pd is decreased is used. By doing so, as in the heating elements 22, the conductors also can be formed by printing. There is a case where due to connections of terminals, it needs to be changed depending on a working temperature. The more Ag is contained, the lower the resistance value may be. The temperature coefficient of resistance of the heating elements 22 is preferably a greater positive number, and it is especially preferable to use a material of 1000-3500 ppm/° C. Also, though it is not illustrated, when an electrode is provided at a suitable position along the flowing direction the electric current of the heating elements 22, a voltage can be partially applied. By doing so, a temperature can vary at positions.
The temperature coefficient of resistance being a large positive number means that as the temperature is elevated, a rate of increase in the resistance value becomes larger. Therefore, with the temperature coefficient of resistance being a positive value, when the temperature is elevated excessively, the resistance value increases and a current value drops, and an amount of heat generation due to resistance is reduced. Therefore, its temperature saturation is reached faster, and its temperature stability at a high temperature is excellent. In addition, overheating due to thermal runaway or the like can be prevented. It should be noted that a width of a normal portion of the heating elements 22 also can be adjusted to a predetermined temperature in accordance with its intended use, and a plurality of the heating elements 22 can be aligned in parallel.
Also, at the both ends of the heating elements 22, the electrodes 23 comprising a good conductor such as a silver-palladium alloy with a smaller proportion of palladium or an Ag—Pt alloy are formed by printing or the like. The electrodes 23, as shown in
Near the heating elements 22, the temperature measurement resistor 24 is formed on a surface of the insulating substrate 21 in the same manner as in the heating elements 22. This temperature measurement resistor 24 is preferably formed along the heating elements 22, as shown in
The temperature measurement resistor 24 may be formed of the same material as the heating element 22, however, a material having an absolute value (%) of the temperature coefficient as large as possible is preferable. This temperature measurement resistor 24 is provided not for generating heat but for detecting and controlling a temperature of the insulating substrate 21 so that the temperature of the insulating substrate 21 reaches the melting temperature of the deposition material. Therefore, the temperature measurement resistor 24 is formed to be a littler shorter than the heating elements 22, with a width of 0.5 mm. Also, an applied voltage is suppressed to be low so that the temperature measurement resistor 24 itself does not generate heat, and for example, about 5V is applied. Because this temperature measurement resistor 24 is provided directly on the insulating substrate 21, the temperatures of the both are almost the same. As a result, by measuring a resistance value of the temperature measurement resistor 24, a temperature of a surface of the insulating substrate 21, and thus a temperature of the deposition material being in close contact with a back surface of the insulating substrate 21 are estimated. That is to say, because, in general, a resistance value of a resistor material is changed when a temperature thereof is changed, the temperature can be measured by measuring the change of the resistance value. While a temperature detection means will be described below, a temperature of the temperature measurement resistor 24 is detected by detecting a voltage change at the both ends of this temperature measurement resistor 24. Therefore, a larger temperature coefficient of the resistor allows a smaller measurement error. It should be noted that the temperature coefficient can be positive or negative in this case.
The temperature measurement resistor 24 is not limited to the same material as the heating elements 22 and formed by printing or the like in accordance with its intended use. Specifically, when a microscopic temperature difference is required, a material having a different mixing ratio of Ag and Pd or a totally different material having a large temperature coefficient may be used. The temperature measurement terminals 25a, 25b are not necessarily formed at the ends of the temperature measurement resistor 24. For example, as shown in
It should be noted that a position where the temperature measurement resistor 24 is formed and a position of the measurement terminal 25 are set in accordance with designs such as the size of the insulating substrate 21 (the first heating plate 2) or the degree of the temperature gradient and the like.
The example shown in
However, the locations thereof may be upside down, and, as shown in
In the example shown in
As mentioned above, the number of the heating elements 22, the number of temperature measurement resistors 24, and the number of measurement terminals for temperature measurement, and the like are not limited. The heating elements 22 are formed by adjusting the number thereof or the width of each of the heating elements 22 so as to be heated to a desirable temperature in accordance with the size of the flow path structure body 1 and the melting point of the deposition material.
When the heating elements 22, the temperature measurement resistors 24, the electrodes 23, and the measurement terminals 25 are formed on one surface of the insulating substrate 21 as shown above, the first heating plate 2 and the second heating plate, which is not illustrated, are formed. On a surface side of this first heating plate 2, the cover substrate 26 is affixed, via a glass adhesion layer, which is not illustrated. The cover substrate 26 may have a smaller thermal conductivity than the insulating substrate 21, but preferably is made of a material having almost the same thermal expansion coefficient as that of the insulating substrate 21 or a material which is the same as that of the insulating substrate 21 and has the same thickness as the insulating substrate 21. On the other hand, in the case where heat is not sufficiently generated with this first heating plate 2, a multiple heating plate may be used, wherein the multiple heating plate is formed by facing the insulating substrates 21, on which these heating elements 22 and others are formed, each other with an insulator interposed therebetween or by putting them together facing in the same direction, with the cover substrate 26 affixed to an exposed surface thereof. More heat may be generated simply by putting the first heating plates 2 together. When such a case is possible, it is preferable that this cover substrate 26 has about the same thermal conductivity as the insulating substrate 21.
In the examples of
The examples shown in
Specifically, the method of forming of a three-dimensional fabricated object of the present invention is characterized in that one surface of the flow paths 12 for discharging the deposition materials is formed by the thin plate 31, the third heating plate 4 is arranged on the opposite side of the flow paths 12 from the thin plate 31, and an instantaneous heating effect is applied on a specific flow path only by the third heating plate 4 so that the deposition material in a specific flow path 12 is discharged. This heating effect is, as will be described below, performed by locally causing a thermal expansion of the deposition material in a specific flow path or a thermal expansion of the thin plate 31 along a specific flow path 12. By providing, between the thin plate 31 and the third heating plate 4, a piece 32 (see
The flow path structure body 1 and attachment thereof to the attaching plate 5, and a configuration of the first heating plate 2 are almost the same as the configurations shown in
Specifically, for example, a plurality of the flow paths 12 can be formed, as shown in
It should be noted that the plates 10 are formed so that the size of the plates 10 is larger than the one in the example shown in
It should be noted that, in each of the above-mentioned examples, a temperature of the heating element having a narrower width is higher because the first heating element 22a and the second heating element 22b are connected in series. However, in the example shown in
When there are a plurality of the flow paths 12, the third heating plate 4 provided on the other side of the flow path structure body 1 is configured so as to be capable of heating each of the flow paths 12 respectively by application of a selective pulsed current by an external signal. When a pulsed voltage is applied to a specific flow path 12 by the third heating plate 4, the flow path 12 is heated via the thin plate 31 and the deposition material inside the flow path 12 is expanded. As a result, the deposition material in the flow path 12 is pushed out and discharged from the discharge opening 13 of the flow path 12. Thus, in this example, the thermal strain generating member 32 (3) shown in
In this case, when the thin plate 31 is formed of a material having a large thermal expansion coefficient, it is expanded along the flow paths thereof and then the deposition materials can be discharged by a change of the thin plate 31 as in the thermal strain generating member, which will be described below. Also, even though the thermal expansion coefficient of the thin plate 31 is not large, the volume of the deposition material itself is increased when the temperature of the deposition materials is raised. As a result, the deposition materials in the flow paths 12 are pushed toward the discharge openings 13 and discharged from discharge openings 13. In this case as well, when the third heating plate 4 is heated instantly, the expansion occurs instantly, and when the heating action is cancelled, the temperature drops and the volume is reduced to normal. Therefore, in any method, the deposition material is discharged instantly, and subsequently the discharging stops. It should be noted that the deposition materials are supplied from the side of the deposition material supply openings only and the deposition materials being melted in the flow paths 12 or being in a fluid state at room temperature are kept being filled in the flow paths 12. When this deposition material is a filament or a rod-shaped material, it is supplied by a barrel. When the deposition material is a photo-curable resin, although its viscosity can vary depending on its type, any of the types is a fluid, and thus, with the discharge openings 13 being set on the bottom side, the deposition material is filled into the flow paths 12 by the self-weight thereof. When it does not fall by the self-weight, it can be filled in the flow path 12 by applying a pressure. Also, even when it is a resin or a metal having a low melting point, it can fall by the self-weight in the same manner as in a particulate material such as a photo-curable resin, when it is formed into a powder.
On the other hand, as shown in
For this thin plate 31, a variety of materials, such as a material having a large thermal expansion coefficient and easy to be deformed or a material having a small thermal expansion coefficient and easy to be deformed, are used in accordance with intended use thereof. Examples of the former materials include a copper alloy such as brass and an aluminum alloy (duralumin) having a thermal expansion coefficient (a coefficient of linear expansion) of 20-30 ppm/° C. Examples of the latter materials include metal plates such as Fe alloys (with different ratios of Fe—Ni—Cr) and stainless steel having a coefficient of linear expansion of about 6 ppm. A non-metal plate may also be used. For this thin plate 31, a material having any thickness of about 0.05-0.6 mm can be used in accordance with its intended use. For example, when the thin plate 31 is formed so as to be deformable by heating along with the pieces 32 as the thermal strain generating member 3, the thin plate 31 and the pieces 32 are affixed together and heated to deform the thin plate 31 by the difference of the thermal expansion coefficients of the thin plate 31 and the pieces 32, and accordingly the deposition material in the flow paths 12 can be discharged. In this case, for the thin plate 31, a material having a thermal expansion coefficient widely different from that of a first piece 32 and easy to be deformed is selected. For example, when the above-mentioned aluminum alloy plate (coefficient of linear expansion: 23 ppm/° C.) or copper alloy (coefficient of linear expansion: about 20 ppm/° C.) is used for the thin plate 31, a 42 Fe—Ni alloy plate (coefficient of linear expansion: 6 ppm/° C.) having a thickness of about 0.1-0.2 mm can be used for the pieces 32. Here, for the plates 10 constituting the flow path structure body 1, a ferroalloy is used. It should be noted that, for example, a bimetal, which will be described below, can be affixed as the thermal strain generating member 3 without employing this thermal expansion coefficient of the thin plate 31. In this case, the thermal expansion coefficient of the thin plate 31 is preferably small. In addition, it may also be possible that, without providing the thermal strain generating member 3, the deposition material in the flow paths 12 is heated and expanded or thermal expansion is caused to the thin plate 31 itself for discharging. In this case, the thin plate 31 is preferably one which is easily deformed largely, and an insulation film or the like may be used. It should be noted that while metals are raised as examples of the thin plate 31 and the pieces 32, materials thereof are not limited to metals, and those other than metals, for example, ceramics used for a ceramic package for semiconductor, a plate of inorganic compound such as a piezoelectric material, quartz glass (coefficient of linear expansion: 0.5 ppm/° C.), and the like may be used.
For example, when the flow path 12 has dimensions of 1 mm (width)×1 mm (depth)×5 mm (length)=5 μl=5,000 nl, the discharge amount (determined by the size of the discharge opening 13) is 0.3 mm×0.3 mm×0.05 mm (width)=0.0045 mm3=4.5 nl the coefficient of volumetric expansion of ABS is (6-13)×10−5 per P° C. Therefore, assuming it is 10×10−5, the volume is expanded by 0.1% by 10° C. increase (when the temperature of 10% of the inside of the flow path 12 is raised by 100° C., the average temperature rise is 10° C.). Therefore, in the case of 5,000 nl×0.1%=5 nl, it is larger than the above discharge amount, and for discharging a small amount, just the thermal expansion of the deposition material is enough.
Also, the pieces 32 constituting the thermal strain generating member 3 are formed along each of the flow paths 12, and in the example shown in
The example shown in
In the above example, a single heater 42 is formed; however, as shown in
To this third heating plate 4, from the view point of microscopic discharging of the deposition materials to a fabricated object, preferably a pulsed voltage is applied. Although the duration of this pulsed voltage application is very short, about several milliseconds, the temperature of the heaters 42 is raised instantly, its heat is transmitted to the pieces 32, and deformation occurs between the pieces 32 and the thin plate 31 or between the pieces 32 and the second pieces 33. The deformation of the thin plate 31 causes the deposition materials to be discharged from the discharge openings 13. This application of a pulsed voltage is performed in the same manner as in application of each pixel signal in a normal thermal printer (for example, see JP S57-98373 A), by inputting data serially to a shift register, and performing a voltage application to only necessary parts by parallel-out. For controlling a heating amount, a duration of pulse application can be changed by setting a latching circuit between this shift register and an AND circuit.
The flow paths 12 are formed in a plurality of rows as shown in the above-mentioned
As the discharge openings 13 are formed in this manner, a pitch between the discharge openings 13 is narrower, and thus more delicate and refined fabricated object can be manufactured. It should be noted that these discharge openings 13e, 13f may be formed not in a single row but in two or more rows. By increasing the number of the plates 10 of the flow path structure body 1 to be put together, a lot of the discharge openings 13 in more than one row can be formed from a single flow path 12. Thus, when a plurality of the discharge openings 13 are formed to be connected to one of the flow paths 12 as described above, a variation of fabricated objects can be obtained. Also, for this refinement, so-called a shuttle system, in which a printhead is moved by about a half pitch in the x-axis direction, may be adopted. The table for a fabricated (formed) object can be moved in the y-axis and z-axis directions as well. By doing so, one movement in the y-axis direction can stack two layers and possibly three or more layers as well.
Also, when there are a lot of the flow paths 12 and a plurality of the discharge openings 13 are formed in line as in the manner mentioned above, even a multicolor-type fabricated object or the like can be manufactured easily. In addition, it is also easier for a base resin and a curative agent to be discharged separately and mixed together. As shown in
When the height of a discharged deposition material is about 1 mm, the level difference “d” is, for example, set to be about 1 mm and the fabricated object is scanned from a direction of the plate 10a which is longer in a scan direction of the fabrication table to a direction of the plate 10b which is shorter in the scan direction so that the discharged deposition material is not be shaved by the printheads even when the deposition material is discharged continuously. As a result, a finely made fabricated object can be formed. On the contrary, the level difference can be formed so as to shave off a top of the discharged deposition material. By doing so, a finely made fabricated object with a flat surface can be formed. The purpose of making such a shape is to make the surface flat to enable the next layer to be adhered easily, and make the material to be discharged and adhered easily when changing characteristics, viscosity, and the like of the material. The purpose of making such a shape also allows for a certain degree of processing of the printed object, such as maintaining a constant thickness of the printed object, maintaining constant intervals between dents, and the like.
Also, instead of the level difference, as shown in
In addition, although it is not shown, the tip of the printhead may be scanned relative to the fabricated object while the printhead is discharging the deposition material in a state of the tip of the printhead being inclined to the fabricated object without facing the fabricated object at a right angle. By doing so, even when the deposition material is discharged continuously, the same effect can be obtained as in the case where the above-mentioned level difference is formed, or the tip is cut in an inclined direction. A thick, fabricated object becomes easier to be obtained. In other words, by changing the shape of the tip of printhead or adjusting the setting angle in accordance with the shape of the fabricated object, even a thick, fabricated object can be formed efficiently.
According to these embodiments, because the deposition material can be suitably discharged from a specific discharge opening 13 of a plurality of the discharge openings 13 by the heating plate 4, for example, while the fabrication table is being scanned, the deposition material can be discharged only on a particular spot on the fabricated object. Also, when a plurality of the discharge openings are formed, two or more spots of the fabricated object can be formed at the same time. In addition, when a plurality of the discharge openings are formed, the discharge amount can be changed by changing the size of the discharge openings. Furthermore, deposition materials of various colors can be discharged. Specifically, the deposition materials can be mixed after being discharged, or deposition materials comprising various colors and materials mixed in advance are prepared so that desired deposition materials are discharged on desirable spots respectively from different discharge openings. As a result, even a large fabricated object can be manufactured freely in a short time.
Also, when a plurality of the printheads having a plurality of the discharge openings formed in line are placed side by side, the number of the discharge openings are further increased, and fabricated objects can be formed at a lot of positions at one time by a single scan. With this configuration, when a resin comprising two liquids are used, a base resin is discharged from the discharge openings of the first row and a curing agent is discharged from the discharge openings of the next row, thereby making it possible to perform reactive curing. In addition, when the discharge openings of a plurality of rows of the printheads are shifted per row in a vertical direction, first, the deposition material is discharged by heads having lower-position discharge openings, and then the deposition material is discharged by a row of the higher-position discharge openings in the same scanning process so that two or more layers of the fabricated objects can be formed by a single scan. Thus, even a large, fabricated object can be formed in a very short time.
When thermal gradient is formed so that the temperature of the first heating plate 2 is higher on the side of the discharge openings 13 than the side of the supply openings side, the deposition material on the side of the discharge openings 13 remains in a state of being melted. Therefore, when a push force is applied to the deposition material due to the deformation of the thin plate into the flow paths 12 or the thermal expansion of the deposition material, the deposition material is likely to be pushed toward the side of the discharge openings 13.
According to the method of the present invention for discharging the deposition material by deformation of the thin plate by the thermal strain generating member or for discharging the deposition material by temperature increase of the deposition material in the flow paths, discharging of the deposition material can be controlled instantaneously, and thus the deposition material can be discharged while the fabrication table is being scanned; therefore, even a large, fabricated object can be manufactured very easily.
In addition, according to the method of the present invention for discharging the deposition material in which the deposition material can be discharged by changing the height of the discharge openings in each of the heads of a plurality of rows in line, two or more layers of a fabricated object can be formed by a single scan, and thus even a large, fabricated object can be formed in a short time. It should be noted that the thickness of each layer can be changed as well.
In
The principle of this temperature measurement will be described with reference to more detailed
- 1 Flow path structure body
- 2 First heating plate
- 3 Thermal strain generating member
- 4 Third heating plate
- 5 Attaching plate
- 6 Barrel
- 7 Closing plate
- 8 LED
- 9 Assembly plate
- 10 Plate
- 12 Flow path
- 13 Discharge opening
- 14 Material supply opening
- 15 Groove
- 16 Attaching portion
- 21 Insulating substrate
- 22 Heating element
- 22a Linear heating element (first heating element)
- 22b Second heating element
- 23 Electrode
- 24 Temperature measurement resistor
- 25a-25d Measurement terminals
- 25e Temperature measurement lead
- 26 Cover substrate
- 27 Lead for heating element
- 28 Temperature measurement lead
- 27a-27d Coupling conductors
- 55 Cylindrical member
- 71 Heat insulation plate
Claims
1. A printhead dispensing a deposition material for three-dimensional fabrication comprising:
- a first heating plate constituting a first side wall portion being a part of a side wall of a flow path for flowing a deposition material, and heating the deposition material in the flow path;
- a closing plate or a second heating plate constituting a second side wall portion, the second side wall portion being a part of the side wall of the flow path other than the first side wall portion;
- a discharge opening communicating with the flow path and formed on one tip of the flow path; and
- a material supply opening communicating with the flow path and formed on another tip of the flow path.
2. The printhead dispensing a deposition material of claim 1, further comprising a flow path structure body, the flow path structure body comprising a plurality of plates having a through-hole of almost the same shape respectively, and the plurality of plates being bonded together so as to form a third side wall portion with peripheral walls of the through-holes, the third side wall portion being a part of the side wall of the flow path other than the first side wall portion and the second side wall portion,
- wherein one end side of the through-hole is closed by the first heating plate; and another end side of the through-hole is closed by the closing plate or the second heating plate, thereby the flow path being formed.
3. The printhead dispensing a deposition material of claim 1, wherein a groove having a concave sectional shape is formed at a portion of the first heating plate, and the closing plate or the second heating plate is provided to close an opening of the concave groove so that the flow path is formed.
4. The printhead dispensing a deposition material of claim 1, wherein the closing plate is formed by a thin plate, a third heating plate is further provided on a side opposite to the flow path based on the thin plate, the third heating plate applying a heating effect on the deposition material in the flow path, and
- wherein the deposition material in the flow path is discharged by instantaneous heating of the third heating plate.
5. The printhead dispensing a deposition material of claim 4, wherein a plurality of the flow paths are formed side by side in a direction perpendicular to an extending direction of the flow path,
- each of the first side wall portions of the plurality of the flow paths is formed by the first heating plate,
- each of the second side wall portions of the plurality of the flow paths is formed by the thin plate,
- the third heating plate is formed to heat only a specific flow path of the plurality of the flow paths, and
- a deposition material is discharged from only the specific flow path by instantaneous heating of the third heating plate.
6. The printhead dispensing a deposition material of claim 4, further comprising a thermal strain generating member bonded between the thin plate and the third heating plate,
- wherein the deposition material in the flow path are discharged due to deformation of the thin plate by heating of the thermal strain generating member by instantaneous heating of the third heating plate.
7. The printhead dispensing a deposition material of claim 6, wherein the thin plate is formed by a metal or nonmetal plate, and the thermal strain generating member is formed by a metal or nonmetal piece having a different thermal expansion coefficient from the thin plate and is a piece bonded to the thin plate along the flow path.
8. The printhead dispensing a deposition material of claim 6, the thermal strain generating member is formed by a bimetal made by bonding at least two kinds of plate materials having different thermal expansion coefficients, and the bimetal is bonded to the thin plate along the flow path.
9. The printhead dispensing a deposition material of claim of 4, wherein the deposition material in the flow path is discharged by a volume increase of the deposition material in the specific flow path caused by a thermal expansion of the deposition material or the thin plate due to heating of the third heating plate or a volume change of the flow path caused by a thermal expansion of the thin plate.
10. The printhead dispensing a deposition material of claim 5, wherein the third heating plate is formed so that heating elements are formed on a second insulating substrate along each flow path of the plurality of the flow paths and cause a heating effect in the specific flow path.
11. The printhead dispensing a deposition material of claim 10, wherein a heating element of the third heating plate formed along the flow path is divided into two or more, and an electrode terminal is formed so that a voltage can be applied to each of the divided heating elements individually.
12. The printhead dispensing a deposition material of claim 1, wherein the first heating plate or the second heating plate comprises:
- a first insulating substrate,
- a belt-shaped heating element, the belt-shaped heating element being formed on a surface of the first insulating substrate and heating the first insulating substrate,
- at least one pair of electrodes, the pair of electrodes being capable of flowing an electric current in a longitudinal direction of the heating element,
- a temperature measurement resistor formed on the surface of the first insulating substrate along the heating element near the heating element, and
- at least one pair of measurement terminals for measuring an electric resistance at a predetermined region of the temperature measurement resistor.
13. The printhead dispensing a deposition material of claim 12, wherein a heating element of the first heating plate is formed so as to be capable of heating the flow path and the neighborhood of the discharge opening, and the heating element is formed so that a temperature of the flow path on a side of the discharge opening is higher than that on a side of the supply opening.
14. The printhead dispensing a deposition material of claim 13, wherein the heating element of the first heating plate has two linear portions of heating elements along a direction of the flow path, each one end of the linear portions being connected with other heating element, and
- wherein a planar shape of the heating element is in a U-shape, and the heating element of the bottom portion of the U-shape is formed so as to be on the side of the discharge opening of the flow path structure body.
15. The printhead dispensing a deposition material of claim 13, wherein the heating element is formed so as to have a portion formed linearly along the direction of the flow path, and
- wherein the linear portion is formed into a tapered shape, or a width of the heating element becomes narrower step by step, or the heating element is partially replaced with conductor layer along the linear portion, thereby making the temperature of the side of the discharge opening higher than the side of the supply opening.
16. (canceled)
17. The printhead dispensing a deposition material of claim 14, wherein at least portions of corners of the U shape are connected with conductor layers.
18. The printhead dispensing a deposition material of claim 2, wherein a recess communicating with the through-holes is formed on at least one of the plurality of plates of the flow path structure body so that the discharge opening is formed.
19. The printhead dispensing a deposition material of claim 1, wherein a plurality of the discharge openings are formed on one of the flow path.
20. The printhead dispensing a deposition material of claim 2, wherein a plurality of the flow path structure bodies are lapped with a heat conductive member or a closing plate being disposed therebetween, and the first heating plate or the thin plate is bonded to the both outer side surfaces of the plurality of the flow path structure bodies.
21. The printhead dispensing a deposition material of claim 2, wherein first and second printheads dispensing a deposition material are bonded with a heat resistance plate interposed so as to face to the first heating plate each other, each of the first and second printheads comprising the flow path structure body, the first heating plate formed on one surface side of the flow path structure body, and a third heating plate formed on the other surface side of the flow path structure body with a thin plate interposed, thereby having a plurality of rows of discharge openings so as to be aligned with discharge openings in the same direction.
22. The printhead dispensing a deposition material of claim 21, wherein each of the flow path structure bodies has a plurality of discharge openings in line, and
- wherein each row of the discharge openings of the plurality of the flow path structure bodies is positioned in a different height in an extending direction of the flow path.
23. (canceled)
24. (canceled)
25. A method of forming a three-dimensional fabricated object, comprising:
- forming one side wall of flow path for discharging a deposition material with a thin plate,
- arranging a third heating plate on the side opposite to the flow path based on the thin plate, and
- fabricating a fabricated object while discharging a deposition material of a specific flow path by applying an instantaneous heating effect only to the specific flow path with the third heating plate.
26. The method of forming of claim 25, wherein the heating effect is applied by locally causing a thermal expansion of the deposition material in the specific flow path or a thermal expansion of the thin plate along the specific flow path.
27. The method of forming of claim 25, wherein the heating effect is applied by providing, between the thin plate and the third heating plate, a piece having a different thermal expansion coefficient from the thin plate or a bimetal, and deforming the thin plate by causing a thermal strain due to the difference of the thermal expansion coefficients resulting from heating of the third heating plate.
28. The method of forming of any one of claim 25, wherein the deposition material is discharged while heating a discharge opening side of the flow path by the first heating plate so that a temperature thereof is higher than that of a supply opening side of the flow path.
29. (canceled)
30. A printhead dispensing a deposition material for three-dimensional fabrication comprising:
- a flow path structure body having a flow path, wherein a discharge opening is formed on one tip of the flow path and a material supply opening is formed on another tip of the flow path, and
- a heating plate for heating the deposition material supplied into the flow path,
- wherein the heating plate forms a part of a side wall forming the flow path.
31. A printhead dispensing a deposition material for three-dimensional fabrication comprising:
- a flow path structure body having a flow path, wherein a discharge opening is formed on one tip of the flow path and a material supply opening is formed on another tip of the flow path, and
- a heating plate for heating the deposition material supplied into the flow path,
- wherein the heating plate comprises an insulating substrate and a heating element provided on one surface of the insulating substrate.
32. The printhead dispensing a deposition material of claim 31, wherein the heating plate is disposed with another surface of the insulating substrate facing toward the flow path.
33. The printhead dispensing a deposition material of claim 31, further comprising another heating plate disposed on the opposite side of the flow path.
Type: Application
Filed: Oct 15, 2015
Publication Date: Jun 21, 2018
Inventors: Hideo TANIGUCHI (Kyoto-shi, Kyoto), Shigemasa SUNADA (Kyoto-shi, Kyoto), Kazuo ODA (Kyoto-shi, Kyoto)
Application Number: 15/574,963