JP6659252B2 - Microfluidic device and method for manufacturing the same - Google Patents

Description

  The present invention relates to a microfluidic device and a method for manufacturing the same. More specifically, the present invention relates to a microfluidic device having a floating member therein and formed by sintering a sintered material compact including a sintered metal powder, and a method for manufacturing the same.

  For example, a check valve is configured to allow fluid to flow in one direction while blocking flow in the opposite direction. Normally, the check valve is provided with a valve body which is displaced or oscillated by the flow of the fluid and a valve seat to which the valve body is brought into close contact, in a cylindrical main body.

  2. Description of the Related Art As a small check valve used in a medical instrument, a chemical analysis instrument, and the like, a valve formed of a polyethylene resin or a fluorine resin is often used. However, the resin check valve has low strength and heat resistance, and is difficult to disinfect and clean.

  In order to solve the above problem, a metal check valve as described in Patent Document 1 has been proposed.

JP 2005-9531 A

  Patent Literature 1 describes a small check valve used for a medical instrument, a chemical analysis instrument, and the like. The check valve is a valve seat provided in the flow path, and seals the flow path by being in contact with one side of the valve seat, and separates the flow of the fluid by separating from the valve seat. And an allowable valve element.

  The valve seat is formed of a plate-shaped member, and the flow passage is formed by forming a through hole in the plate-shaped member. The valve body is formed of a very thin metal plate, and includes a fixed portion fixed near the through hole, an arm portion extending from the fixed portion, and an opening / closing portion provided at a tip of the arm portion. It is provided with.

  The fixed portion, the arm portion, and the opening / closing portion are formed to have different thicknesses by etching a thin stainless steel plate, and are configured to elastically displace the opening / closing portion by a fluid pressure. Have been.

  In the invention described in Patent Document 1, it is necessary to separately process the valve seat and the valve body, and then to assemble these members with high accuracy. In particular, in the case of a minute check valve, if the mounting position of the valve seat and the valve element is slightly deviated, the function as the check valve may not be able to be performed, and the assembling work is troublesome.

  Further, in order to form the valve seat, a through hole must be formed in the plate member with high accuracy. Further, etching is performed to make the thickness of the fixed portion, the arm portion, and the opening / closing portion of the valve body different. However, it is difficult to ensure the accuracy of the thickness of the plate material by the etching operation. Also, the steps and operations of the etching operation are troublesome.

  Further, it is necessary that the periphery of the through hole and the fixed portion be in close contact with each other without a gap. For this reason, surface accuracy of the fixed part and the valve seat is also required.

  An object of the present invention is to solve the above-mentioned conventional problems and to provide a microfluidic device having high accuracy and durability with a small number of steps and at low cost.

The present invention is a microfluidic device including a hollow main body having a fluid inlet and a fluid outlet, and a floating member movably held in the hollow main body, wherein the hollow main body includes a sintered metal powder and While containing a binder component, a sintered material compact having a predetermined shrinkage ratio during sintering is sintered and integrally formed, while the floating member is formed of a material that does not sinter with the metal powder. The floating member is inserted into the molded body of the sintered material before the sintering, and then, by performing the sintering, the floating member is movable and non-separable in the hollow body contracted at the contraction rate. Along with being held in the hollow main body, a regulating portion for regulating the flow of the fluid by contacting the floating member is provided, and the regulating portion transfers the form of the floating member during the sintering. It is formed.

  The microfluidic device according to the present invention is formed from a sintered metal. Therefore, a microfluidic device requiring high temperature and strength, and a microfluidic device requiring corrosion resistance can be formed. Further, a microfluidic device requiring high pressure resistance can be formed. Furthermore, a microfluidic device can be manufactured from various metals in accordance with the type of fluid and the like.

  The sintered material compact constituting the hollow body shrinks by sintering, but the floating member does not shrink. In the present invention, the floating member that does not shrink is assembled in the hollow body so as to be movable and non-separable by utilizing the shrinkage of the sintered material molded body during sintering.

  In the microfluidic device according to the present invention, not only the overall size is small, but also the hollow body is formed by sintering a sintered metal powder, and the floating body is swung in the hollow body. It is configured to include members. Further, the hollow body is sintered together with the floating member and is confined in the hollow body. For this reason, unless the shrinkage rate is controlled with high accuracy, the floating member cannot be freely movably held in the hollow main body and cannot be detached.

  That is, in order to hold the floating member in the hollow main body so as to be movable and non-removable, while providing an opening through which the floating member can be inserted in the hollow body before sintering, the opening after sintering is provided. It is necessary to contract the floating member to such a size that the floating member does not come off.

  It is preferable to set the shrinkage ratio of the sintered sintered compact by sintering to 10% to 25% so that the floating member can float and cannot be separated. When the shrinkage is less than 10%, the difference between the size of the opening and the size of the floating member becomes small, and it becomes difficult to insert the floating member into the hollow main body. In addition, the fluidity of the molding material having the shrinkage of 10% or less is low, and it is difficult to mold a molded body with a predetermined accuracy. On the other hand, when the shrinkage ratio exceeds 25%, unnecessary deformation occurs in the hollow main body, and the shape accuracy is reduced.

  When a hollow main body having a cylindrical shape is employed, the hollow main body can be formed with an outer diameter of 1 to 5 mm and a wall thickness of 0.05 to 0.5 mm. When the outer shape of the hollow main body is less than 1 mm, it is difficult to form a highly accurate cylindrical body. When the outer diameter of the hollow body exceeds 5 mm, the size of the fluid element itself increases. Further, it is difficult to accurately form a wall having a thickness of less than 0.05 mm. When the thickness of the wall exceeds 0.5 mm, the size of the fluid element increases. Preferably, the outer diameter of the hollow body is set to 2 to 5 mm, and the thickness of the wall is set to 0.1 to 0.4 mm. The external dimensions correspond to the diameter of a resin tube or the like that is frequently used in test equipment or medical equipment, and many of them have been made of resin or the like until now. Since the microfluidic device according to the present invention can be formed of metal, it has high strength and heat resistance, and can be applied to fluids and devices that have been unusable up to now. Moreover, since it has a cylindrical form, it can be easily installed on a piping line.

  The type of the sintered metal is not particularly limited. For example, a microfluidic device having high heat resistance and high corrosion resistance can be formed using stainless steel powder. In addition, the particle size of the sintered metal powder constituting the sintered material is not particularly limited, and the sintered metal powder having a particle size capable of forming the sintered material compact according to the molding method to be adopted and the dimensions of the compact. Can adopt body. In the case of forming a fine compact, it is preferable that the sintered metal powder has a small particle size. For example, when a cylindrical body having a diameter of about 1 to 3 mm is formed, it is preferable to use a cylindrical body having an average particle size D50 of 1 to 3 μm.

  The binder component is not particularly limited. It can be formed from various resin materials as long as it can be filled in a mold to form a sintered material molded body and can be eliminated in the degreasing step. Further, the binder that can be eliminated by heat is not limited, and a binder that can be eliminated from the sintered material molded body by a solvent such as water or alcohol can be adopted. For example, when a sintered material molded body is molded by injection molding, it is preferable to employ a material that can impart fluidity at the time of molding by the binder and can secure shape retention after molding.

  Since the hollow main body constituting the microfluidic device according to the present invention is formed by molding a sintered metal powder, no post-processing such as cutting is required. Therefore, the number of manufacturing steps can be reduced, and the manufacturing cost can be reduced. Further, a microfluidic device having a complicated form and a flow path can be easily formed.

  The floating member according to the present invention is movably and non-separably confined in the hollow main body by utilizing shrinkage when sintering the sintered metal powder. That is, the sintering step is performed in a state where the floating member is accommodated in a sintered material molded body formed from the sintered metal powder. For this reason, the floating member is formed of a material that does not sinter with the sintered metal powder in the sintering step. For example, when stainless powder is used as the metal powder, the floating member can be formed from a ceramic material that does not sinter with the stainless powder. Further, while forming the hollow body from the first metal sintered powder that is sintered at a low temperature, the floating member does not melt at the sintering temperature of the first metal powder, and It can also be formed from a second metal material that does not sinter with the first metal powder.

  The form of the floating member is not particularly limited. For example, a spherical or conical floating member can be employed. In addition, floating members having various functions can be used.

  In order to control the fluid flowing in the hollow main body with high accuracy, it is necessary to increase the accuracy of a regulating portion (for example, a contact surface) that regulates the flow of the fluid by bringing the floating member into contact with the inner surface of the hollow main body. . For example, it is preferable that the check valve is configured so that the valve body and the valve seat can be in close contact with high accuracy. Conventionally, the contact surface between the floating member and the hollow body has been separately processed. For this reason, a gap or the like is likely to be formed on the contact surface, and the control accuracy of the fluid often decreases.

  In the present invention, the regulating portion provided in the hollow main body and configured to regulate the flow of the fluid when the floating member is brought into contact is formed by transferring a part of the form of the floating member during the sintering. be able to. In order to transfer the form of the floating member, it is preferable to perform sintering while pressing the floating member against a predetermined portion of the hollow body. As a method of pressing the floating member against a predetermined portion of the hollow main body, gravity can be used. For example, the sintering process can be performed by utilizing the own weight of the floating member, further applying a required weight to the floating member, and pressing the floating member against the regulation portion forming portion with a required force. On the other hand, since the hollow body shrinks in the sintering step, the form of the contact portion of the floating member is transferred to the predetermined part of the hollow body only by pressing with a force enough to position the hollow body.

  In the present invention, since the regulation portion can be formed by transferring the form of the floating member, it is possible to form a regulation portion with extremely high accuracy (for example, a contact surface between the valve element and the valve seat). . Moreover, even when the precision of the shape of the floating member is low, the contact surface is formed by the transfer, so that the precision of the contact can be increased. For this reason, it is possible to easily form a microfluidic device having high control accuracy without requiring precise processing.

  The present invention can be applied to various microfluidic devices. For example, the present invention can be applied to a microfluidic device that functions as a check valve. In addition, a microfluidic element that stirs two or more fluids is provided by providing two or more fluid inlets in the hollow main body and oscillating the floating member in the hollow main body by the flow of the fluid. can do. In addition, two fluid outlets are provided, and an inlet and an outlet for a control fluid are provided separately from the fluid outlet and the fluid inlet, so that the idler member is selectively positioned at the second fluid outlet by the control fluid. It is also possible to form a microfluidic device having the configured switching valve function.

  The microfluidic device according to the present invention has a core forming step of forming a core formed of a resin material while having a form corresponding to the hollow portion of the hollow body, and a hollow mold corresponding to the outer form of the hollow body. A core installation step of installing the core in a mold provided with a portion, and the sintered metal powder in a molding space formed by an inner surface of the hollow mold portion and an outer surface of the core. A molding step of forming a sintered material molded body by filling a molding material containing a and a binder, and a molded body taking out step of integrally taking out the sintered material molded body and the core from the mold, The core disappearing step of eliminating the core and the binder, the floating member forming step of forming the floating member with a material that does not sinter with the sintered metal powder, and the sintering in which the core has disappeared Floating part for inserting the floating member into the inside of the molded material An insertion step, sintering the sintered material molded body into which the floating member is inserted, and utilizing the shrinkage of the sintered material molded body, the floating member can float in the hollow main body and is not detachable. And a sintering step for confining as much as possible.

  The core forming step can be performed using various techniques. For example, the core can be formed by injection molding a resin material that disappears in the degreasing step. Further, a resin material can be formed by cutting or the like.

  The molding step is performed by filling a molding material containing a sintered metal powder and a binder component into a mold provided with the core. Since the hollow body according to the present invention has a very small size, it is preferable to use an injection molding method.

  In the microfluidic device according to the present invention, the filling space of the molding material is smaller than the size of the mold. In addition, since the molding material contains metal powder, it has high thermal conductivity. For this reason, when manufacturing using the injection molding method using a metal powder, when the molding material is filled in the mold, the temperature of the molding material is rapidly lowered, and the molding material is in every corner of the mold. Is difficult to fill. By forming the core from a resin material, a decrease in the temperature of the molding material can be reduced, and the moldability in injection molding or the like can be improved.

  The core installation step can be performed by installing the core manufactured in another step in the mold. Further, the core forming step and the above-described forming step of forming the hollow main body can be continuously performed using a two-color forming method or the like.

  The step of removing the molded body is performed by integrally removing the sintered material molded body and the core from the mold. Although the sintered material molded body according to the present invention has a very small size, it is possible to prevent the sintered material molded body from being damaged when being separated from the mold by being taken out integrally with the core. it can. Further, handling up to the next degreasing step is also facilitated. Further, handling is further facilitated by providing a projection or the like for handling on the core.

  The core elimination step can be performed using various techniques. For example, the core and the binder can be eliminated by evaporating the resin constituting the core and the binder by heating. In addition, the core and the binder can be eluted and eliminated using various solvents.

  In the core elimination step, it is not necessary to completely eliminate the binder component. By leaving a part of the binder component, handling up to the sintering step and shape retention in the sintering step can be enhanced.

  In the floating member forming step, the floating member is formed of a material that does not sinter with the sintered metal powder. For example, the floating member can be formed by molding and sintering a ceramic powder having a sintering temperature higher than that of the hollow body. In the present invention, the form of the floating member is not particularly limited, and various forms of the floating member can be adopted by molding or cutting.

  In the present invention, the floating member is held in the hollow main body so as to be movable and non-separable. Therefore, the outer diameter of the core is set so that the inner diameter of at least one of the fluid inlet side and the fluid outlet side in the sintered material molded body is larger than the maximum outer shape of the floating member. Thus, in the floating member inserting step, the floating member can be easily inserted into the sintered material molded body from which the core has been eliminated.

  The sintering step is performed by heating the sintered material compact to a predetermined temperature to sinter the metal powder. The sintering temperature is set according to the employed sintered metal powder. In the present invention, not only is the sintered metal powder sintered, but also the shrinkage of the sintered material compact is used to lock the floating member in the hollow body so as to be movable and non-separable. For this reason, the sintering step is performed so that the inner diameter of the hollow body on both sides of the floating body holding space is smaller than the maximum outer diameter of the floating member.

  In order to shrink the formed body so that the floating member can move freely and cannot be detached, the shrinkage ratio of the sintered body due to sintering is preferably set to 10 to 25%. When the shrinkage is less than 10%, the difference between the size of the opening and the size of the floating member becomes small, and it becomes difficult to insert the floating member into the hollow main body. On the other hand, when the shrinkage ratio exceeds 25%, unnecessary deformation occurs in the hollow main body, and the shape accuracy is reduced. In addition, the floating property of the floating member in the hollow main body is reduced.

  The kind and particle size of the metal powder, the blending ratio of the binder component and the metal powder, and the like are set so that the shrinkage ratio is obtained.

  In the above-described manufacturing method, the floating member is inserted into the sintered material molded body after the core has disappeared. However, the floating member may be held inside the core when the core is formed.

  That is, the step of preparing the floating member, the core having the form corresponding to the hollow portion of the hollow main body, the core holding the floating member inside, the core forming step of forming from a resin material, A core installation step of installing the core in a mold provided with a hollow mold part corresponding to the outer form of the hollow body, and a molding comprising the inner surface of the hollow mold part and the outer surface of the core. In a space, a molding step of filling a molding material containing the sintered metal powder and the binder to form a sintered material molded body, and forming the sintered material molded body and the core from inside the mold Integrally removing the molded body, removing the core and the binder, and sintering the sintered material molded body, and allowing the floating member to float inside the hollow body; Including a sintering process that locks up In can be produced.

  When the above method is adopted, the step of inserting the floating member can be omitted, and the manufacturing process can be simplified. Further, since it is not necessary to insert the floating member into the hollow main body after the core has disappeared, the degree of freedom of the range of the shrinkage ratio of the sintered material molded article is increased.

  As described above, since the microfluidic device according to the present invention has a very small size, when the molding material is filled into a mold by using an injection molding method, the temperature of the molding material rapidly decreases, and There is a possibility that the moldability may be deteriorated and the moldability may not be secured.

  In order to alleviate the above-mentioned problem, in the above-described manufacturing method, a material corresponding to a part or the whole of the hollow mold portion is provided in the mold by using a material that disappears in the core disappearing step and / or the sintering step. A sacrificial mold part forming step of forming a mold part can be included. That is, the core for molding the inner space of the hollow body and the sacrificial mold for molding the outside are both made of resin. As a result, the heat retention in the molding die is enhanced, the temperature of the molding material filled in the molding space is prevented from lowering, and the moldability can be improved.

  Further, in the molded body removing step, the sintered material molded body, the core, and the sacrificial mold portion can be integrally removed. The sintered material compact is released from the mold while the outside is surrounded by the sacrificial mold. For this reason, it is possible to not only prevent the occurrence of damage at the time of release, but also to facilitate handling up to the degreasing step.

  When the above-mentioned sacrificial mold portion is adopted, it is preferable that the portion where the resin is injected into the molding space and the vicinity thereof are formed of a mold. That is, since the molded product according to the present invention has a small size, it is preferable to inject the molding material directly from the mold portion into the molding space in order to accurately inject the molding material into the mold.

  In the present invention, the floating member is held inside the hollow main body, and the fluid is controlled by the interaction with the inner surface of the hollow main body. For this reason, the shape accuracy of the part (regulation part) which the floating member contacts or contacts is required. However, since the dimensions of the hollow body are very small, it is difficult to machine the contact surface by post-processing after sintering.

  In the present invention, in the sintering step, at least a part of the outer surface configuration of the floating member is transferred to the inner surface of the hollow portion of the sintered material molded body in the sintering process. Thereby, the contact surface between the hollow main body and the floating member can be brought into contact with high accuracy, and the flowing fluid can be reliably controlled.

  As a method for performing the transfer, gravity acting on the floating member can be used. For example, the sintering step is performed in a state where the contact surface of the hollow body is located below the floating member and the floating member is in contact with the contact surface. Since the hollow member shrinks in the sintering step, the sintering step is performed by positioning the floating member at a predetermined position of the hollow member, whereby the contraction proceeds while the contact surface of the floating member is transferred. Thereby, the contact surface of the floating member can be transferred to the hollow member.

  By adopting the above method, it is possible to form a regulating portion (contact surface) that can accurately contact the floating member inside the hollow member. Moreover, even when the accuracy of the shape of the floating member is low, the contact accuracy of the contact surface can be ensured. In particular, when controlling a liquid such as blood, if the contact surface between the valve body and the valve seat is large, blood components may be destroyed. In the present invention, the contact surface with high precision can be formed very small by transferring a part of the form of the floating member to the corner formed in the hollow body. For this reason, a fluid element in which blood components and the like are not easily destroyed can be provided.

  In the sintering step, in addition to the force of the floating member by its own weight, another force can be applied to transfer the form of the floating member. For example, the sintering step can be performed while placing a weight on which a predetermined gravity acts on the floating member, or applying elasticity to the floating member using a spring member or the like.

  A highly accurate and durable microfluidic device can be provided at low cost.

It is a front view showing the appearance of the check valve concerning the present invention. It is sectional drawing which follows the axis | shaft of the check valve shown in FIG. It is a right view of the check valve shown in FIG. It is sectional drawing in which the core of the metal mold | die apparatus which shape | molds the check valve shown in FIG. 1 was installed. FIG. 5 is a cross-sectional view illustrating a state in which a molding material is filled in a molding space of the mold apparatus illustrated in FIG. 4. FIG. 6 is a cross-sectional view illustrating a state where a molded body molded by the mold apparatus illustrated in FIG. 5 is taken out together with a core. FIG. 7 is a cross-sectional view illustrating a state in which a core is removed from the molded body illustrated in FIG. 6. It is sectional drawing which shows the state which inserts a floating member into the inside of the molded object shown in FIG. FIG. 5 is a cross-sectional view of a mold device according to a second embodiment, which forms a sacrificial mold portion for manufacturing the check valve shown in FIG. 1. It is sectional drawing which follows the XX line in FIG. FIG. 10 is a cross-sectional view illustrating a state where a sacrificial mold portion of the mold apparatus illustrated in FIG. 9 is molded. It is sectional drawing which shows the state which installed the core corresponding to the inside of the check valve in the sacrificial type | mold part shown in FIG. FIG. 13 is a cross-sectional view showing a state in which a molding material containing a sintered metal powder and a binder component is filled in the molding space shown in FIG. 12. FIG. 14 is a cross-sectional view showing a state where a core, a sacrificial mold part, and a sintered material molded body have been integrally taken out from the mold apparatus shown in FIG. 13. It is sectional drawing of the sintered material molded object which concerns on 3rd Embodiment, Comprising: It is sectional drawing which shows the procedure which transfers some forms of a floating member. It is a principal part enlarged view of FIG. 15, and is a figure which shows the state which made the floating member contact the contact part in a hollow main body. FIG. 16 is an enlarged sectional view of a main part showing a form after a sintering step is performed in the state shown in FIG. 15.

  An embodiment according to the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to a check valve 1 having a spherical valve element 4 therein as a microfluidic element. However, other microfluidic devices having other forms of floating members therein are provided. The present invention can be applied to the element.

  1 to 3 show an outline of a minute check valve 1 according to the present invention.

  As shown in FIG. 1, the check valve 1 is held movably inside a cylindrical tubular main body 3 provided with ridges 2, 2 for preventing the connection tube from coming off on the outer periphery of both ends. And a spherical floating member 4.

  The cylindrical main body 3 has a fluid inlet 5 into which fluid flows in on one side, and a fluid outlet 6 on the other end. A floating member holding space 7 for movably holding the floating member 4 is provided at the center. The flow path 8 on the fluid inlet side of the floating member holding space 7 is formed smaller than the outer diameter of the floating member 4. On the other hand, the flow path 18 on the fluid outlet 6 side is formed larger than the outer diameter of the floating member 4. On the fluid outlet 6 side of the floating member holding space 7, a pair of convex portions 9, 9 for preventing the floating member 4 from separating to the fluid outlet side are formed, and between the convex portions 9, 9. Are formed with gaps 10 that allow the fluid to flow.

  In the check valve 1 having the above-described configuration, when the fluid flows in from the fluid inlet 5, the floating member 4 is hooked on the pair of protrusions 9, 9, and the fluid flows from the gaps 10, 10. Flow toward the fluid outlet. On the other hand, when the fluid tries to flow in from the fluid outlet side, the floating member 4 is configured to be in close contact with the tapered edge 11 of the flow path 8 on the fluid inlet side. There is no backflow towards the inlet 5. Thereby, the function as a check valve is exhibited.

  The cylindrical main body 3 according to the present embodiment has an outer diameter of 2.4 mm, a length of 8 mm, and a minimum thickness of a wall of 0.2 mm. For this reason, it is difficult to form a metal by cutting. In the present invention, it is formed by an injection molding method using a sintered metal powder described below.

  The cylindrical body 3 includes a sintered metal powder and a binder component, and is integrally formed by sintering a sintered material molded body having a predetermined shrinkage ratio during sintering. Is formed from a ceramic material that does not sinter with the metal powder. In this embodiment, SUS316L stainless steel powder is used as the sintered metal powder. The stainless steel powder preferably has a particle size (D50) of 2 μm or less. The floating body 4 is formed by sintering an alumina-based powder as the ceramic material. The floating member 4 is inserted into the sintered material molded body before the sintering, and then sintering is performed so that the floating member 4 can freely move and cannot be separated into the contracted cylindrical main body 3. It is trapped and held.

  4 to 8 show an example of a method for manufacturing the check valve 1 shown in FIG.

  As shown in FIG. 4, the inside of the check valve 1 is inserted into a mold apparatus 100 including a pair of molds 101 and 102 having recesses 103 and 104 corresponding to the outer shape of the check valve 1. A core 106 corresponding to the form is installed. The recesses 103 and 104 and the core 106 are formed corresponding to a state before the sintered material compact shrinks.

  The core 106 is integrally formed of resin, and both ends thereof are sandwiched by core support portions 101a, 102a and 101b, 102b provided at both ends of the recesses 103, 104, so that the recesses are formed. It is supported between 103 and 104. A molding space 109 corresponding to the cylindrical main body 3 is formed between the outer surface of the core 106 and the inner surfaces of the recesses 103 and 104. Although FIG. 4 shows that the molding material injection port 105 is provided at an intermediate portion of one of the dies 101, it is actually formed on the mating surface of the pair of dies 101 and 102.

  As shown in FIG. 5, a molding material 107 is injected into the molding space 109 from the molding material injection port 105. In the present embodiment, a molding material 107 containing a sintered metal powder and a binder component is injected into the molding space 109 from the molding material injection port 105 using an injection molding method.

  The molding material 107 is configured to include stainless steel powder and a binder, impart fluidity by melting the binder, and is filled into a molding space 109 of the mold device 100 by an injection molding device. You. On the other hand, the core 106 is formed of a resin that can be eliminated by heating to a predetermined temperature in a subsequent degreasing step. For example, the core 106 can be formed of a polyacetal resin or the like. The method of forming the core 106 is not particularly limited. For example, it can be molded by an injection molding method.

  Since the core 106 is formed of a resin material, when the molding material 107 is injected into the molding space 109, a decrease in the temperature of the molding material can be reduced. Thereby, the molding material 107 can be filled to every corner of the molding space 109.

  As shown in FIG. 6, the sintered material molded body 110a formed from the molding material 107 and the core 106 are integrally taken out from the concave portions 103 and 104 of the mold apparatus 100. As shown in FIG. 6, since the core 106 and the sintered material molded body 110a can be integrally taken out from the mold apparatus 100, the mold apparatus can be used without damaging the sintered material molded body 110a. 100 can be taken out. Further, handling in the subsequent steps is facilitated.

  The binder contained in the core 106 and the sintered material molded body 110a taken out of the mold apparatus 100 is eliminated in the core eliminating step. The core elimination step is performed by heating to a temperature at which the resin material constituting the core 106 disappears, as described above. It is not necessary to completely remove the binder component in the molding material 107 in the core elimination step. In order to secure the shape retention in the subsequent sintering step, it may be left at a required ratio. Further, the core disappearing step may be performed by immersing the sintered material molded body 110a in a solvent in which the resin constituting the core 106 is dissolved. By performing the core elimination step, a sintered material molded body 110a having the form shown in FIG. 7 is formed.

  As shown in FIG. 8, the spherical floating member 4 is inserted from the fluid inlet 5a side into the floating member holding space 7a of the sintered material molded body 110a from which the core 106 has disappeared. A flow path 8a from the fluid inlet 5a of the sintered material molded body 110a to the floating member holding space 7a has a diameter larger than that of the floating member 4. Therefore, the floating member 4 can be easily inserted into the floating member holding space 7a.

  The sintered material molded body 110a into which the floating member 4 is inserted is heated to a predetermined temperature in a state where the floating member 4 is accommodated in the floating member holding space 7a, and the sintered metal forming the sintered material molded body 110a is heated. The powder is sintered.

  When sintering the sintered material compact 110a, the shrinkage of the sintered material compact 110a is set such that the diameter of the flow path 8a is equal to or less than the diameter of the floating member 4. In the present embodiment, the shrinkage ratio of the sintered material compact 110a is set to 15%. Thereby, the diameter of the flow path 8a can be reduced to be smaller than the diameter of the floating member 4.

  The floating member 4 is formed of a ceramic material that does not sinter with the sintered metal powder constituting the sintered material compact 110a. For this reason, even if the sintered material compact 110a is sintered together with the floating member 4, the floating member 4 can be sintered in the floating member holding space 7a in a freely movable state.

  By adopting the above-mentioned manufacturing method, as shown in FIG. 1, the floating member 4 can be locked inside so as to be movable and not detachable.

  9 to 13 show another method of manufacturing the check valve 1 according to the present invention.

  As described above, the check valve 1 according to the present embodiment has a very small size. For this reason, if a normal metal mold is used, it is difficult to precisely fill the mold with the molding material. In the embodiment described above, the resin is used for the core to reduce the temperature drop of the molding material at the time of filling. However, in the present embodiment, in addition to the core, the outer mold (sacrifice mold) is formed of the resin. Is what you do.

  As shown in FIG. 9, concave portions 203 a. 204a is provided. The recesses 203a. Although the injection port 205a for injecting the molding material into the mold 204a is described as being provided in the middle part of the mold 201 in FIG. 9, it is actually formed on the mating surface of the mold 201 and the mold 202. ing. Similarly, an injection port 205b for injecting a molding material constituting the sintered material molded body is also formed on the mating surface of the mold 201 and the mold 202.

  As shown in FIG. 10, the concave portions 203a and 204a according to the present embodiment are not formed on the entire inner surfaces of the molds 201 and 202, and are separated on the side provided with the injection port 205b for injecting a molding material. It is not formed near the surfaces 201a and 202a.

  A core 206a corresponding to the external form of the check valve 1 is installed in the space between the recesses 203a and 204a. The outer surface of the core 206a and the recesses 203a. A resin material 207a forming the core 6 in the first embodiment is filled into the molding space 209a formed by the inner surface of the check valve 204a from the injection port 205a. Mold portions 203b and 204b are formed. The sacrificial mold portions 203b and 204b have the same configuration as the concave portions 103 and 104 in the first embodiment described above.

  As shown in FIG. 10, in the present embodiment, the sacrifice mold portions 203a and 204b are configured to be separable together with the molds 201 and 202. Therefore, after the sacrificial mold portions 203b and 204b are formed, the molds 201 and 202 are separated, and the core 206a is taken out of the molds 201 and 202. In addition, a half-shaped sacrificial mold portion may be formed so as to surround the entire core 206.

  Core supports 201a, 202a and 201b, 202b similar to those of the first embodiment are formed on the sacrificial molds 203b, 204b and the molds 201, 202. Then, as shown in FIG. 12, a core 106 similar to that of the first embodiment is installed on the core support portions 201a and 202a and 201b and 202b.

  Accordingly, a molding space 209b corresponding to the cylindrical main body 3 is formed between the outer surface of the core 106 and the inner surfaces of the sacrificial mold portions 203b and 204b.

  As shown in FIG. 13, the molding space 210b is filled with a molding material 210 containing a sintered metal powder and a binder component from a molding material injection port 205b. The molding material injection port 205b is also formed on the mating surface of the mold 201 and the mold 202.

  Next, as shown in FIG. 14, the sacrificial mold parts 203b and 204b, the core 106, and the sintered material molded body 210a are integrally taken out of the mold apparatus 200. The sintered material molded body 210a is filled with the core 106 on the inner side and provided with the sacrificial mold parts 203b and 204b on the outer side. There is no risk of deformation. For this reason, the release operation and subsequent handling become easy.

  A core removing step is performed on the sacrificial mold portions 203b and 204b, the core 106, and the sintered material molded body 210a in the same manner as in the first embodiment. In the core eliminating step, the binder components in the sacrificial mold portions 203b and 204b, the core 106, and the molded body 210a are eliminated.

  Thereafter, as in the above-described embodiment, the floating member is inserted, and the sintering step is performed. Note that the floating member inserting step and the sintering step are the same as those in the above-described embodiment, and thus description thereof will be omitted.

  By adopting the above manufacturing method, it is possible to prevent a decrease in temperature at the time of filling the mold with the molding material containing the sintered metal powder and the binder component. For this reason, moldability can be further improved. In addition, it is possible to form a highly accurate product.

  15 to 17 show a third embodiment of the present invention.

  As described above, since the check valve 1 according to the present invention has a small size, it is difficult to secure the contact accuracy of the contact portion between the floating member 104 and the cylindrical main body 310 by post-processing or the like.

  In the third embodiment, after the floating member 104 is inserted into the sintered material molded body 310a, the form of the contact portion 352 of the floating member 104 is changed in the sintering step by the inlet flow of the sintered material molded body 310a. The image is transferred to the edge of the road 353a.

  As shown in FIG. 16, in the present embodiment, the diameter of the inlet-side flow path 308a in the sintered material molded body 310a is set smaller than the diameter of the floating member 104, and a tapered portion 351a is formed on the inner edge. The floating member 104 is formed so as to abut the edge 353a of the tapered portion.

  A state in which the floating member 104 is in contact with the edge 353a, that is, a state in which the surface of the floating member 104 is pressed against the edge 353a by the gravity acting on the floating member 104, as shown in FIG. Sintering is performed.

  In the sintering step, the sintered material compact 310a is sintered while shrinking by a predetermined amount. Therefore, as shown in FIG. 17, the edge 353a of the sintered material compact 310a is contracted while being deformed along the surface of the floating member 104. Thereby, a part of the surface configuration (spherical surface) of the floating member 104 is transferred to the edge 353a, and the contact portion 353b to which the surface configuration of the floating member 104 is transferred is formed.

  Since the contact portion 353b has the surface shape of the floating member 104 transferred with high precision, the contact accuracy between the floating member 104 and the contact portion 353b is extremely high, and a contact structure having airtightness can be obtained. it can. Therefore, a check valve having a high check effect can be formed.

  Moreover, even if the contact area of the contact portion 353b is set small, the contact accuracy is high, and a high check effect can be obtained. Therefore, when applied to a fluid such as blood, the particle components of blood are less likely to be caught between the contact surfaces, and the amount of the blood components destroyed can be reduced.

  The present invention is not limited to the above embodiment. In the present embodiment, the present invention is applied to a check valve, but can be applied to other devices having a floating member therein.

  The microfluidic device can be manufactured with high accuracy and at low cost.

1 Check valve (microfluidic element)
3 tubular body (hollow body)
4 Floating member 5 Fluid inlet 6 Fluid outlet 110a Sintered material molded body

Claims (8)

A microfluidic device including a hollow body having a fluid inlet and a fluid outlet, and a floating member movably held in the hollow body,
The hollow body includes a sintered metal powder and a binder component, and is integrally formed by sintering a sintered material molded body having a predetermined shrinkage ratio during sintering, while the floating member is formed of the metal. It is formed from a material that does not sinter with the powder,
The floating member is inserted into the sintered material molded body before the sintering, and then sintering is performed, so that the floating member is held in the hollow body shrunk at the shrinkage ratio so as to be movable and non-separable. Along with
In the hollow body, provided with a regulating portion that regulates the flow of the fluid is contacted with the floating member,
The microfluidic device , wherein the restricting portion is formed by transferring the form of the floating member during the sintering .   2. The microfluidic device according to claim 1, wherein a shrinkage rate of the sintered material compact by sintering is 10% to 25%.   The microfluidic device according to claim 1, wherein the hollow main body has a cylindrical shape, and has an outer diameter of 1 to 5 mm and a wall thickness of 0.05 to 0.5 mm. The microfluidic device according to any one of claims 1 to 3 , wherein the microfluidic device is a check valve. A method for manufacturing a microfluidic device according to any one of claims 1 to 4 , wherein
A core forming step of forming a core formed from a resin material while having a form corresponding to the hollow portion of the hollow body,
In a mold provided with a hollow mold part corresponding to the outer form of the hollow body, a core installation step of installing the core,
A molding step of filling a molding material including the sintered metal powder and the binder into a molding space formed by the inner surface of the hollow mold portion and the outer surface of the core to form a sintered material molded body When,
A molded body removing step of integrally removing the sintered material molded body and the core from the mold,
A core disappearing step of eliminating the core and the binder,
A floating member forming step of forming the floating member with a material that does not sinter with the sintered metal powder;
A floating member insertion step of inserting the floating member inside the sintered material molded body,
Sintering the sintered material compact into which the floating member is inserted, and utilizing the shrinkage of the sintered material molded body, sintering the floating member inside the hollow body so as to be movable and irremovable. Including a binding step ,
In the sintering step, a method of manufacturing a microfluidic device, wherein at least a part of an outer surface configuration of the floating member is transferred to an inner surface of the hollow portion of the sintered material compact in a sintering process . A method for manufacturing a microfluidic device according to any one of claims 1 to 4 , wherein
Preparing the floating member;
With a form corresponding to the hollow portion of the hollow body, a core holding the floating member inside, a core forming step of forming a resin material,
In a mold provided with a hollow mold part corresponding to the outer form of the hollow body, a core installation step of installing the core,
A molding step of filling a molding material including the sintered metal powder and the binder into a molding space formed by the inner surface of the hollow mold portion and the outer surface of the core to form a sintered material molded body When,
A molded body removing step of integrally removing the sintered material molded body and the core from the mold,
A core disappearing step of eliminating the core and the binder,
Sintering the sintered material molded body, including a sintering step of movably and undetachably enclosing the floating member inside the hollow body ,
In the sintering step, a method of manufacturing a microfluidic device, wherein at least a part of an outer surface configuration of the floating member is transferred to an inner surface of the hollow portion of the sintered material compact in a sintering process . The method for manufacturing a microfluidic device according to claim 5 , wherein a shrinkage rate in the sintering step is set to 10% to 25%. A sacrificial mold part forming step of forming a sacrificial mold part corresponding to part or all of the hollow mold part in the mold using a material that disappears in the core disappearing step and / or the sintering step. With
In the molded body removing step, the sintered material molded body, the core, and the sacrificial mold portion are integrally removed,
The method of manufacturing a microfluidic device according to any one of claims 5 to 7 , wherein the sacrificial mold portion is eliminated in the core eliminating step and / or the sintering step.

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