HYDRODYNAMIC AND GRAVITY METHOD OF FORMING AND SHAPING TAPERED MICROFLUIDIC DEVICES AND PRODUCTS
20230373149 · 2023-11-23
Inventors
- Eleanor Augusta Derbyshire (Lexington, KY, US)
- Candace Eileen Gillette (Lexington, KY, US)
- John Edward Estes (Nicholasville, KY, US)
Cpc classification
B01L2200/12
PERFORMING OPERATIONS; TRANSPORTING
B01L3/502707
PERFORMING OPERATIONS; TRANSPORTING
B29C71/04
PERFORMING OPERATIONS; TRANSPORTING
B29C48/266
PERFORMING OPERATIONS; TRANSPORTING
B29C48/21
PERFORMING OPERATIONS; TRANSPORTING
B29C48/32
PERFORMING OPERATIONS; TRANSPORTING
B29K2033/08
PERFORMING OPERATIONS; TRANSPORTING
International classification
B29C48/25
PERFORMING OPERATIONS; TRANSPORTING
B29C71/04
PERFORMING OPERATIONS; TRANSPORTING
B29C48/21
PERFORMING OPERATIONS; TRANSPORTING
B29C48/09
PERFORMING OPERATIONS; TRANSPORTING
B29C48/32
PERFORMING OPERATIONS; TRANSPORTING
Abstract
A method for forming extruded microtube devices and products having a hollow portion utilizing a hydrodynamic nozzle, a curable fluid, and a core fluid to form flexible polymer based microtubes having an inner diameter ranging from 500 nanometers to 500 micrometers and also continuous microtubes having a varying inner diameter ranging from about 500 nanometers to 500 micrometers. The outer diameter can be variable and have a cross-sectional shape that is circular, rectangular, square, triangular, elliptical, star, irregular, curved, or formed within a solid block of material.
Claims
1. A method for forming an extruded shape, comprising: a) providing a hydrodynamic nozzle; b) providing a curing system; c) providing a material bed; and d) providing a control system; e) optionally providing a pressure system; f) optionally providing a fluid drain system; g) simultaneously introducing a curable sheath fluid and a core fluid from the hydrodynamic nozzle to form a concentric extrusion comprising an external sheath fluid and an internal core fluid; h) depositing at least a portion of the concentric extrusion on the material bed; I) causing relative motion between the hydrodynamic nozzle and the material bed to form an extruded shape; j. at least partially curing a portion of the external curable fluid; k) optionally introducing the concentric extrusion to pressure from the pressure system to remove the internal core fluid from the external curable fluid; and l) optionally receiving the core fluid into the fluid drain system.
2. The method of claim 1, wherein at least partially curing a portion of the external sheath fluid may occur before or after depositing at least a portion of the concentric extrusion on the material bed.
3. The method of claim 1, wherein the curing system is an ultraviolet (UV) curing system.
4. The method of claim 1, wherein the core fluid is a smart fluid.
5. An apparatus for forming an extruded shape comprising: a) a hydrodynamic nozzle for creating a concentric extrusion formed of an external curable fluid and an internal core fluid; b) a curing system for at least partially curing the external curable fluid; c) a pressure system for removing the internal core fluid from the external curable fluid; a material bed for receiving at least a portion of a concentric extrusion; e) a control system for causing relative movement between the hydrodynamic nozzle and a material bed; and f) a fluid drain system for receiving the core fluid.
6. The apparatus of claim 5, wherein the curing system is an ultraviolet (UV) curing system.
7. The apparatus of claim 5, wherein the pressure system provide positive or negative pressure.
8. The apparatus of claim 5, wherein the material bed may be capable of simultaneous linear movement in x-, y- or z-directions.
9. The apparatus of claim 5, wherein the material bed may be capable of simultaneous movement in x-, y-, z- or theta-directions.
10. The apparatus of claim 5, further comprising a ferro system that is capable of changing the position or cross-section of a shape.
11. A method for forming an extruded shape, comprising: a) providing a hydrodynamic nozzle capable of forming an extrusion comprising an external curable fluid and an internal core fluid; b) providing a curing system; c. providing a material bed; d.) providing a fluid drain system comprising at least one fluid drain; e) providing a control system; f) providing relative motion from the control system so that the hydrodynamic nozzle is positioned proximate to a fluid drain in the material bed; g) forming an extrusion from the hydrodynamic nozzle so that the external curable fluid is in communication with the material bed, and the internal core fluid is in communication with the fluid drain; and h) providing relative motion from the control system while simultaneously forming an extrusion from the hydrodynamic nozzle to form a shape having at least a hollow portion.
12. A method for forming an extruded shape, comprising: a) providing a hydrodynamic nozzle; b) providing a curing system; c) providing a material bed; and d) providing a control system; e) providing a gravity fed system; f) optionally providing a fluid drain system; g) simultaneously introducing a curable sheath fluid and a core ferro fluid from the hydrodynamic nozzle to form a concentric extrusion comprising an external sheath fluid and an internal core fluid; h) exposing the core fluid to a magnetic force; I) depositing at least a portion of the concentric extrusion on the material bed; j) causing relative motion between the hydrodynamic nozzle and the material bed to form an extruded shape; k) at least partially curing a portion of the external curable fluid; l) optionally introducing the concentric extrusion to pressure from the pressure system to remove the internal core fluid from the external curable fluid; and m) optionally receiving the core fluid into the fluid drain system.
13. A method for forming an extruded shape, comprising: a) providing a hydrodynamic nozzle capable of forming an extrusion comprising an external curable fluid and an internal core fluid containing a ferro fluid; b) providing a curing system; c. providing a material bed; d.) providing a fluid drain system comprising at least one fluid drain; e) providing a control system; f) providing relative motion from the control system so that the hydrodynamic nozzle is positioned proximate to a fluid drain in the material bed; g) forming an extrusion from the hydrodynamic nozzle so that the external curable fluid is in communication with the material bed, and the internal core fluid is in communication with the a magnetic force and the fluid drain; and h) providing relative motion from the control system while simultaneously forming an extrusion from the hydrodynamic nozzle to form a shape having at least a hollow portion.
14. A tapered microtube product made from the method for forming an extruded shape of claim 1, comprising a tapered microtube comprising a polymer, with internal circular cross section, the tapered microtube having an inner diameter that is smaller at one end increasing to larger at the other end, with the smaller end inner diameter measuring about 500 nm to about 500 um, the larger end inner diameter measuring about 50 um to about 10 mm, the larger end to smaller end inner diameter ratio about 5:1 to about 100:1.
15. The tapered microtube product of claim 14, wherein, said tapered microtube comprises an inner surface roughness of from 2 to 5 nm.
16. The tapered microtube product of claim 14, wherein, said tapered microtube comprises an inner surface roughness of from 6 to 20 nm.
17. The tapered microtube product of claim 14, wherein said polymer is selected from the group consisting of an ultraviolet reactive setting polymer, a chemically reactive setting polymer, a thermoplastic polymer, a thermoset polymer, a transparent polymer, a translucent polymer, and an opaque polymer.
18. The tapered microtube product of claim 14, wherein said microtube comprises a tapered microtube inner diameter surface continuously increasing from the small end to the large end with the change of diameter from small to large end generally following a parabolic curve with continuously changing curvature radius, up to a maximum infinite radius at either or both ends.
19. The tapered microtube product of claim 14, wherein said microtube comprises a tapered microtube inner diameter surface continuously increasing from the small end to the large end with the change of diameter from small to large end generally following a parabolic curve with continuously changing curvature radius, up to a maximum infinite radius at either or both ends, and said tapered microtube smoothly decreasing then increasing again in a single section or a multiplicity of sections, while the overall primary taper shape increases in inner diameter from smaller at one end to larger at the other end.
20. The tapered microtube of claim 14, wherein a tapered microtube inner diameter axis is coaxial with outer diameter axis.
21. The tapered microtube of claim 14, wherein a tapered microtube inner diameter axis is not coaxial with outer diameter axis.
22. The tapered microtube of claim 14, wherein a tapered microtube inner diameter axis is coaxial with outer diameter axis in some sections and not coaxial with outer diameter in other sections.
23. The tapered microtube of claim 14, wherein an overall length ranges from 5 mm to about 1 meter.
24. The tapered microtube of claim 14, wherein an outer diameter ranges from 10 um to about 20 mm.
25. The tapered microtube of claim 14, wherein said microtube is reusable by flushing with water or water-surfactant mixture heated up to a temperature of 100 C.
26. The tapered microtube of claim 14, wherein said microtube is reusable by flushing with common solvents or organic compounds.
27. The tapered microtube of claim 14, wherein said microtube includes means for connection at one end, both ends, or along the outer length of the device that enable permanent or separable connection with other devices.
28. The tapered microtube of claim 14, said microtube connecting to biotechnology microfluidic device.
29. The tapered microtube of claim 14, wherein said microtube is used in a biotechnology microfluidic device and comprises a micro nozzle, a micro nozzle with in-nozzle mixing effect, a micro flow restrictor, a micro aspiration tip, a micro dispense tip, a reagent, a microsample, a micro nutrient delivery path, a cell aligner, a cell, a protein, a particle sorter, and combinations thereof.
30. The tapered microtube of claim 14, wherein said microtube is used in a precision instrument component device and comprises a micro nozzle, a micro nozzle with in-nozzle mixing effect, a micro flow restrictor, a micro aspiration tip, a micro dispense tip, a micro cooling fluid, heating fluid, or lubrication fluid delivery path, and combinations thereof.
31. The method of forming an extruded shape according to claim 10, wherein said ferro core fluid is composed of a plurality of magnetic solid nano particles having a diameter of up to 10 nanometers of magnetite, hematite or compound containing iron, and a liquid to disperse them evenly within a carrier fluid.
32. The method of forming an extruded shape according to claim 31, wherein said carrier fluid is an oil.
33. The method of forming an extruded shape according to claim 31, wherein said ferro core fluid contains a surfactant.
34. The method of forming an extruded shape according to claim 31, wherein said surfactant is selected from the group consisting of an oleic acid, a tetramethylammonium hydroxide, a citric acid, a soy lecithin, and combinations thereof.
35. The method of forming an extruded shape according to claim 10, wherein said ferro core fluid contains about 5 percent magnetic solid nano particles, about 10 percent of as surfactant, and about 85% of a carrier fluid.
36. The method of forming an extruded shape according to claim 10, wherein said ferro core fluid viscosity is from 1-10 centipoise.
37. The method of forming an extruded shape according to claim 10, wherein said ferro core carrier fluid is glycerin.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0111] It is to be understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present disclosure. It is to be understood that the present disclosure is not limited in its application to microfluidic applications set forth in the following description. The present disclosure is capable of other embodiments and of being used in various applications.
[0112] Reference to documents made in the specification is intended to result in such patents or literature cited are expressly incorporated herein by reference, including any patents or other literature references cited within such documents as if fully set forth in this specification.
[0113] It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Further, the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.
[0114] Any extruded shape, even if extruded onto a planar surface, is considered “three-dimensional” since the extrusion has a thickness, and additional process disclosed herein may cause a varying thickness.
[0115] The term “sheath fluid” is interchangeable with “focusing fluid”.
Hydrodynamic Focusing Apparatus and Method
[0116] By controlling the core fluid and sheath fluid volume flow rates, the dimensions of the extrusions can be altered without the application of physical changes to the apparatus.
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[0121] There is also shows a material bed 140 for receiving the extrusion 50. Extrusion 50 is normally flexible prior to curing. Material bed 140 provides a surface for forming 2-dimensional (2D) and three-dimensional (3D) shapes. A material bed axis 145 provides three-degrees of freedom for forming shapes from extrusion 50. These include x-, y-, and z-translation. Having two separate axes (115 and 145) enables greater flexibility in forming shapes from extrusion 50. We therefore describe motion as “relative motion” since both axes 115 and 145 may contribute. A control system 200 provides control to all electrical systems of the machine system 100, which will be described in detail with reference to
[0122]
[0123] An extruded shape that is at least partially cured in situ may be created in free space, wherein a shape may be extruded to make contact with the material bed 140 but then be moved away from the material bed 140 (in a y-direction), translated in an x- or z-direction in free space, then again making contact with the material bed 140.
[0124]
[0125] For certain core fluids or certain shapes, the core fluid 15 used in the production of a concentric extrusion 50 requires removal. In some scenarios, the final shape may be cured, trimmed if needed, and any core fluid 15 may be removed using manual methods. In other scenarios, however, auto-removal of the core fluid 15 may be preferred.
[0126] Fluid removal system 160 is comprised of at least one fluid port 170 that is exposed to the top surface (as shown) of the material bed 140. A pressure system 180 enables positive or negative pressure to be applied. If more than one fluid port 170 is included, valves 190 enable pressure (positive or negative) to be applied only to the fluid port 170 that is in fluidic communication with the extrusion 50. By closing valves that are in fluid communication with any open fluid ports 170, pressure can be more efficiently directed to the extrusion 50. For some extrusions 50 that are extremely flexible, it may be preferred to at least partially cure the extrusion 50 prior to removing the core fluid 15 to avoid inflating (if positive pressure is used) or collapsing (if negative pressure is used) the extrusion 50.
[0127] In operation, the leading end of the extrusion 50 is placed in fluid communication with a fluid port 170 prior to shape formation. Curing or partial curing may occur during extrusion. Once the extrusion 50 is completed and has been severed from the hydrodynamic nozzle assembly 110, pressure may be applied using the pressure system 130. It is preferred that the severed end of the extrusion 50 be at least partially opened during application of pressure.
[0128] In
[0129] The control system 200 is supplied power by a power supply 280. The control system 200 may include a communication interface or module 220 coupled to a shape processing module 230. The shape processing module 230 may be communicatively coupled to an extrusion module 240, a positioning module, 250, a curing module 260, a pressure module 270, and a ferro module 275.
[0130] The shape source 210 may be any type of device capable of transmitting data related to a shape file to be formed by machine system 100 in cooperation with the shape processing module 230. The shape source 210 may include a general-purpose computing device, e.g., a desktop computing device, a laptop computing device, a mobile computing device, a personal digital assistant, a cellular phone, etc. or it may be a removable storage device, e.g., a flash memory data storage device, designed to store data such as shape data. If, for example, the shape source 210 is a removable storage device, e.g., a universal serial bus (USB) storage device, the communication interface 220 may include a port, e.g., a USB port, to engage and communicatively receive the storage device. In another embodiment, the communication interface 220 may include a wireless transceiver to allow for the wireless communication of shape data 215 between the shape source 210 and the control system 200. Alternatively, the communication interface 220 may facilitate creation of an infrared (IR) communication link, a radio-frequency (RF) communication link or any other known or contemplated communication system, method or medium.
[0131] The communication interface 220 may be configured to communicate with the shape source 210 through one or more wired and/or wireless networks. The networks may include, for example, a personal area network (PAN), a local area network (LAN), a wireless local area network (WLAN), a wide area network (WAN), etc. The networks may be established in accordance with any number of standards and/or specifications such as, for example, IEEE 802.11x (where x indicates a, b, g and n, etc.), 802.16, 802.15.4, Bluetooth, Global System for Mobile Communications (GSM), code-division multiple access (CDMA), Ethernet, etc.
[0132] The shape processing module 230 may receive the shape data 215 from the communication interface 220 and process the received shape data 215 to create a shape job 225 for use within the machine system 100. Alternatively, the processing of the shape data 215 may be performed by the shape source 210 or other device or module and the resulting shape job 225 may be communicated to the communication interface 220. The processed shape data 215 and/or shape job 225 may, in turn, be provided to the shape processing module 230. The shape processing module 230 can cache or store the processed shape data 215 or may communicate the shape data 215 in real-time for shape job 225 creation.
[0133] The shape processing module 230 sends the shape job 225 to the extrusion module 240, positioning module 250, curing module 260, and optionally the pressure module 270 if using a pressure system 180 with the material bed 140, and optionally the ferro module 275 if ferro fluid is used as the core fluid 15. The extrusion module 240 controls the extrusion parameters based on material properties of the sheath fluid 25 and core fluid 15, and desired shape outcome. The extrusion module 240 is configured to cooperate with positioning module 250, which includes positioning data for the nozzle axis 115 and material bed axis 145. Alternately, if the mandrel 150 is used instead of the material bed 140, the positioning module 250 includes positioning data for the nozzle axis 115 and mandrel axis 155. Position sensors 290 provide feedback for closed-loop location information. Sample position sensors 290 include optical encoders (not shown) that may be linear or rotary strips having scale markings that are detected by optical sensors. An analog or digital signal may provide position feedback based on the number of scale markings detected by the optical sensors. Pressure module 270 receives information from the shape processing module 230 whether core fluid 25 will be removed by pressure or not. If core fluid 25 is to be removed, the magnitude and direction of pressure (such as low vacuum pressure or moderate positive pressure) will be determined based on the anticipated properties of the extrusion 50 at the time pressure is to be applied. The pressure module 270 will also control any valves 190 if multiple fluid ports are available for use. If there is only one fluid port, there is no need for valves 190.
[0134] As shown in
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[0137] Temperature controlled first sheath conduit 30 and second core conduit 40 deliver the sheath fluid 25 and core fluid 15 respectively from sheath fluid supply 125 and core fluid 130 to the hydrodynamic nozzle assembly 110. Viscosity of the fluids is lowered by heating and increased by cooling.
[0138] The funnel contains the sheath fluid 25 with a nozzle on the inside that delivers the core fluid 15. Both fluids then exit the nozzle of the funnel together coaxially and both fluids are reduced in diameter due to the gravity focusing effect. Permanent magnet used when one uses a ferro fluid as the core fluid is greater when use do change the shape of the inner tube diameter. UV curing light with 405 nm wavelength can be used to cure the falling sheath fluid 25 in one preferred embodiment. A material bed such as a substrate mounted onto a movable drive (xyz stage motion) to catch the cured stream and/or to allow build up and a different channel to create patterns.
[0139] By controlling the core fluid 15 and sheath fluid 25 volume flow rates, the dimensions of the extrusions can be altered without the application of physical changes to the apparatus.
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[0142] The heated filling hose for the sheath fluid and the core fluid and the holder for the outer funnel. Heating the hose controls the viscosity of the fluids. The higher the viscosity the longer the manufactured tube body. The lower the viscosity, the less bubbles are produced in the tube body. The holder for the outer funnel is adjustable in the x and y directions so as to make sure the inner nozzle is perfectly centered in the outer funnel nozzle so that the core stream is centered in the sheath steam such that the inner and outer diameters of the manufactured tube are concentric as shown in
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[0145] The pressurized pot delivering sheath fluid to the funnel, and showing the temperature control system for the sheath and core fluids to control the viscosity, and the insulation covering the heating element and the delivery hose for the core/sheath fluids as shown in
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[0148] The hydrodynamic nozzle assembly 110 has a core fluid steam 15 introduced into a clear outer sheath fluid stream 25 wherein the inner blue core fluid 15 is surrounded by the clear liquid sheath fluid 25. The diameter of the sheath fluid 25 is the same as the nozzle at the nozzle exit 108 and quickly necks down to about 1/10 of that within a short distance and both the core fluid 15 and coaxial sheath fluid 25 continue to taper only slightly thereafter and the using this gravity focusing effect and curing the UV curable sheath fluid, hollow tubes with inner diameters as small as 200 nm have been created.
[0149] The following examples describe preferred embodiments of the intention. Other embodiments within the scope of the claims herein will be apparent to one skilled in the art from consideration of the specification or practice of the invention as disclosed herein. It is intended that the specification, together with the examples, be considered exemplary only, with the scope and spirit of the intention being indicated by the claims which follow the examples. The present disclosure will be more readily appreciated with reference to the example which follows.
Example 1
[0150] An extruded shape in the form of an “S” is desired which is shown in
[0151] The sheath fluid 25 is capable of being partially cured using typical curing wavelengths. The curing system 120 is a 35-watt UV LED light ring attached to the hydrodynamic nozzle assembly 110. The material bed 140 includes a top surface of transparent glass. Below the material bed 140 is a 35-watt UV LED array.
[0152] The extruded shape was drawn and converted to a vector file, which is the shape data 215. The shape data 215 was received by the communication interface 220 and sent to the shape processing module 230 for processing into a shape job 225. The shape job 225 was sent to the extrusion module 240, the positioning module 250, and the curing module 260.
[0153] The machine system 100 was then activated, the hydrodynamic nozzle assembly 110 was preheated to 100° F. (37.8° C.), and sheath fluid 25 and core fluid 15 were introduced to the hydrodynamic nozzle assembly 110 via first conduit 30 and second conduit 40, respectively. The hydrodynamic nozzle assembly 110 moved to a close proximity (within 25 mm) to the material bed 140, which is planar. Extrusion from the hydrodynamic nozzle assembly 110 was activated, and the nozzle axis 115 and material bed axis cooperated to produce relative motion between the hydrodynamic nozzle assembly 110 and the material bed 140 that resulted in an “S” shape being extruded onto the material bed 140. After extrusion, the hydrodynamic nozzle assembly 110 was moved to a central position above the shape, and the curing system 120 was activated. Both the UV LED light ring and the UV LED array were activated simultaneously for 12 seconds (10 seconds minimum and a safety margin of 2 seconds). After 12 seconds, the curing system 120 was deactivated, and the hydrodynamic nozzle assembly 110 and the material bed 140 were returned to a home position, enabling the user to manually remove the shape for trimming and removal of the core fluid 25.
Example 2
[0154] The sheath fluid 25 used was a polyacrylate. The core fluid was water. The inner diameter of the sheath fluid was 0.03 mm (30 microns). A random three-dimensional shape was created as shown in
Example 3
[0155] The sheath fluid 25 used was a dipentaerythritol pentaacrylate. The core fluid was an electro rheological fluid EMG 700 from Ferrotec USA Corporation, located in Santa Clara, California. The inner diameter of the sheath fluid was 0.03 mm (30 microns). A random three-dimensional shape was created according to aspects of the present disclosure. See
Manufacture of Tubular Plastic (Polymers) Using Body Force Focusing (Gravity Focusing)
[0156] This method uses co-flow of two immiscible fluids that exit a nozzle, chute, ledge, beaker edge or the like (all termed “nozzle”), simultaneously, and one totally encased by the other, but not necessarily at the same flow rates. The motive force for the co-flowing fluids from the “nozzle” may be gravity, centrifugal force or any other body force generation method. The outer fluid is termed the sheath fluid and the inner fluid is termed the core fluid. A distinguishing characteristic of the flow from the “nozzle” is that the diameter or width of sheath fluid is reduced as it exits the “nozzle”. The core fluid, likewise, is reduced in width or diameter. This reduction in width or diameter is commonly termed “focusing”, and the motive force is a body force, like gravity, it is further termed “gravity focusing”. Gravity focusing is distinguished from the commonly used method of hydrodynamic focusing in that, hydrodynamic focusing generates co-flow from a nozzle into a constrained channel, whereas gravity focusing generates co-flow from a nozzle into unconstrained free space. A further distinguishing factor is that hydrodynamic focusing relies on surface forces (like applied pressure) to force the sheath and core fluids through converging nozzles to provide focusing, whereas gravity focusing relies upon the body force of gravity, the initial geometry of the nozzle, the sheath and core viscosities and the surface tension between the nozzle and sheath fluid at the exit to provide focusing.
[0157] The flow of material for a gravity focusing system is characterized by the jet shape and depends on the dynamic viscosity of the Newtonian fluid typically forming a concave jet, flow velocity at the nozzle resulting in a straight, vertical shape, falling height forming a vertical jet, and the flow of material application onto a moving substrate whereby the flow of material forms a convex shape.
[0158] This method further relies on the sheath fluid being comprised of a fast curing, liquid plastic that can be cured by different means but preferentially using ultra-violet light, and the core fluid being non-curable, but immiscible with the sheath fluid, so as the core and sheath fluid remain co-flowing and do not mix as the co-flowing jet travels away from the nozzle exit. The fast curing UV lights are positioned some distance below the nozzle exit and some distance away from the co-flowing sheath and core fluids. The exact distances depend upon the tubular geometry desired. As the co-flowing fluid stream passes between the UV lights they are activated such that the sheath fluid is cured into a solid plastic material. That material is then removed either as a discrete part or spooled onto a mandrel in a continuous fashion, depending upon the tube design objectives. The core fluid may remain inside the tube, may be cleaned out of the tube or replaced by another material inside the tube depending upon the design and use intent.
[0159] This method has advantages over other tube making methods in that it can be used to focus the core material into very small diameters (as small as 200 nm have been achieved). It can be used to make tubes with core materials of larger diameters, limited only by the nozzle design. Microtubes at least up to 2 mm have been achieved and the tubes can be made with tapered core diameters. Furthermore a plurality of microtubes can be bundled for higher flow rate and/or surface area or flow rate. The resulting inner diameter of the tube has a superior surface as compared to polished, drawn, traditional micro machined, injection molding, extruding and other methods (1-5 nm Ra which is a mirror finish) because the process essentially molds the sheath fluid around a core fluid and the core fluid has a very smooth surface roughness (molded parts take on the surface roughness of the molds used to make them). Upon forming microsized core diameters, the tubes can be further processed into microfluidic chips (2D networks of channels) and microfluidic bricks (3D networks of channels) by molding the tubes into a larger matrix of the UV curable material.
Example 4
[0160] A 100 mL beaker with approximately 25 mL of highly viscous, UV curable sheath material and 5 mL of significantly less viscous core material was used where the core material specific gravity is greater than that of the sheath material such that it remains inside the sheath material as a ball of material (doesn't float to the top and spread out). The beaker was simply tilted by hand such that the sheath material began to flow over the edge of the spout and the flow of the sheath material began to draw from the ball of the core material until a small stream of the core material formed on the inside of the sheath material, both materials co-flowing over the edge of the beaker. Due to the high viscosity and surface tension of the sheath material, a significantly tapered flow was seen from the exit of the beaker to the free stream. A hand-held radiation device, such as a UV light, was used to cure the sheath material just prior to it collecting onto a substrate such as a material bed, resulting in solid diameters of plastic tubing with micro sized inner diameters.
[0161] The plastic tubing was then cast into a larger chip of UV cured material and the inner channels were accessed by drilling and then gluing connectors in place. In this manner a microfluidic flow chip of 3D nature was created.
[0162] A funnel nozzle or an L-shaped chute can be utilized as the nozzle. The sheath fluid is maintained in the funnel or chute using a syringe pump or a pressurized pot with a hose. The core fluid is injected into the sheath fluid using a syringe pump with a syringe and a dispense tip or syringe needle depending upon the design intent. As the fluids exit the nozzle, UV curing lamps under automatic control are actuated to cure the material. The material either collects onto a substrate plate or is captured in free space and removed as a discrete tubular section. A mandrel is not yet implemented but can be used to collect the tubular section in a continuous fashion to create very long tubes of several feet in length and the length is only limited by the length of the mandrel.
[0163]
[0164]
[0165] As illustrated in
[0166] Gravity fed extrusion of SR399 and ferro fluid, is cured as it takes shape as shown in
[0167] Fluids streams are acted upon using other process manipulations, as well as externally applied forces (including, but not limited to, magnetic, acoustic, mechanical vibration, and mechanically induces deflection) to produce defined features and shaping of the cavities in the cured solid.
Variations on System Configuration Parameters
[0168] The experimental embodiment described in the examples is flexible and the apparatus is altered to provide various product configurations, including at least one or more of the following steps of: [0169] a) One core fluid stream feeds into the sheath fluid stream; [0170] b) Multiple core fluid streams feed into a sheath fluid stream; [0171] c) Collection of core fluid streams are rotated during feed into sheath stream and curing process; [0172] d) Core fluid stream feeds into a fluid stream that feeds into a third, outer fluid stream; [0173] e) UV curing in area of maximum flow focus to produce funnel-like shapes; [0174] f) UV curing further removed from mechanical outlet for more constant diameter tubing; [0175] g) Flat substrate to capture shorter length extrusions; [0176] h) Spool to capture longer length extrusions; [0177] I) Mandrel with associated UV curing to create formed components; [0178] j) Motion axes to move receiving substrate or mandrel; [0179] k) Motion axes to move, tilt, or rotate fluid outlet; [0180] l) Various shaped mechanical structures leading into fluid outlet; [0181] m) Fluids provided by pressure pot, syringe pump, alternate pump type, and/or reservoir with gravity feed; [0182] n) Fluid streams flowing undisturbed to the curing zone; [0183] o) Fluid streams acted on by external forces such as magnetic, acoustic, mechanical vibration, mechanical deflection, or the like, to create shaped features in a tube inner cavity; [0184] p) Fluid streams acted on by external forces such as magnetic, acoustic, mechanical vibration, mechanical deflection, or the like, to vary the inner diameter of cured tube; [0185] q) Fluid streams acted on by external forces such as magnetic, acoustic, mechanical vibration, mechanical deflection, or the like, to vary the axial position of the inner core relative to the OD axis of the cured tube; [0186] r) Non-UV cure inside UV cure material; [0187] s) UV cure material inside non-UV cure material; [0188] t) Non-UV cure inside UV cure inside non-UV cure; [0189] u) UV cure inside UV cure material; and [0190] v) UV cure inside UV cure inside non-UV cure.
[0191] It is contemplated and will be clear to those skilled in the art that modifications and/or changes may be made to the embodiments of the disclosure. Accordingly, the foregoing description and the accompanying drawings are intended to be illustrative of the example embodiments only and not limiting thereto, in which the true spirit and scope of the present disclosure is determined by reference to the appended claims.