An extrusion printing head and a method of manufacturing the same

Abstract

This invention discloses an extrusion printhead and its manufacturing method, relating to the field of 3D printing technology. The extrusion printhead includes a printhead body, the first end of which is used to connect to a printing device. An extrusion channel is located at the end of the printhead body, and the wall of the extrusion channel has microstructures penetrating the sidewall to form a discontinuous interface. The wall of the extrusion channel is treated with wettability control to achieve a hydrophilic, superhydrophilic, hydrophobic, or superhydrophobic state, thereby confining and guiding the fluid at the air interface of the discontinuous interface. The extrusion printhead manufactured using the method of this invention can reduce extrusion resistance, reduce shear stress damage to cells, and improve cell viability after printing with cell bio-ink.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to an extrusion printhead and its manufacturing method. Background Technology

[0002] As one of the core technologies of additive manufacturing, extrusion 3D printing has been widely used in many fields such as structural ceramic preparation, flexible electronic device processing, biological tissue scaffold construction, and microfluidic device research and development, thanks to its advantages such as flexible molding process, wide range of material adaptability, and controllable manufacturing cost.

[0003] The core component of current extrusion 3D printing is the print head with a continuous solid wall structure. Its flow channels are mostly designed as closed, continuous structures such as cylinders, cones, or rectangles, achieving the delivery and constrained extrusion of printing material through a complete solid wall. However, this traditional structure has revealed many intractable technical problems in practical applications, severely restricting the development and application expansion of extrusion printing technology. Firstly, high-viscosity materials exhibit significant extrusion resistance, easily leading to printhead clogging and damage. Traditional continuous solid walls create a large solid-liquid contact area between the printing ink and the wall, generating substantial frictional resistance. For high-viscosity non-biological materials such as ceramic slurries, high-concentration conductive hydrogels, and magnetic slurries, extremely high extrusion pressure is often required to achieve material delivery. This not only increases the power requirements of the printing equipment but also easily causes printhead nozzle clogging, flow channel wear, or even overall damage, reducing the lifespan of the printing equipment and the continuity of printing.

[0004] Secondly, small-diameter, high-precision printing makes it difficult to achieve low-resistance extrusion of cell bio-inks. In microscale, high-resolution printing scenarios, the printhead nozzle diameter needs to be less than 100μm. However, in traditional continuous wall structures with small-diameter flow channels, the extrusion resistance increases exponentially. The excessive shear stress generated will significantly reduce the cell viability after printing, resulting in a narrow process window for high-resolution extrusion bioprinting, making it difficult to balance printing accuracy and cell viability.

[0005] In summary, the structural defects of traditional continuous solid wall extrusion printheads result in significant shortcomings in extrusion pressure, necessitating a technical solution that can reduce extrusion resistance. Summary of the Invention

[0006] The purpose of this invention is to provide an extrusion printhead and its manufacturing method to solve the problems existing in the prior art, reduce extrusion resistance, reduce shear stress damage to cells, and improve cell survival rate after cell bio-ink printing.

[0007] To achieve the above objectives, the present invention provides the following solution: This invention provides an extrusion printhead, comprising: A printhead body, the head end of which is used to connect to a printing device; and An extrusion channel is located at the end of the printhead body. The wall of the extrusion channel has microstructures that penetrate the sidewall of the extrusion channel to form a discontinuous interface. The wall of the extrusion channel is treated with wettability control to form a hydrophilic, superhydrophilic, hydrophobic or superhydrophobic state to achieve confinement and guided extrusion of fluid at the air interface of the discontinuous interface.

[0008] In one embodiment, the internal flow channel shape of the extrusion channel is a straight flow channel structure or a conical flow channel structure; the cross-section of the extrusion channel is circular or polygonal.

[0009] In one embodiment, the printhead body and the extrusion channel are integrally formed, and the printhead body and the extrusion channel are made of plastic, metal, glass or ceramic.

[0010] In one embodiment, the microstructure is a slit and / or a micropore; the slit and / or micropore is made by laser cutting, tool processing, ion beam etching, chemical etching or 3D printing.

[0011] In one embodiment, when the extrusion channel wall has slits, a plurality of slits are circumferentially arranged on the sidewall of the extrusion channel; the slits are straight, wavy, or spiral in shape.

[0012] In one embodiment, when the extrusion channel wall is provided with micropores, a plurality of micropores are arranged circumferentially on the sidewall of the extrusion channel; the shape of the micropores is circular, elliptical or polygonal.

[0013] In one embodiment, when the extrusion channel wall is provided with micropores, multiple sets of hole groups are arranged circumferentially on the sidewall of the extrusion channel, and each hole group includes multiple micropores arranged along the axial direction of the extrusion channel; the shape of the micropores is circular, elliptical or polygonal.

[0014] In one embodiment, when the extrusion channel wall is provided with micropores and slits, the micropores and slits are arranged at intervals along the circumference of the extrusion channel.

[0015] In one embodiment, the wettability control treatment is performed by dip coating, spray coating, sputtering coating, plasma treatment, chemical etching, or laser processing.

[0016] The present invention also provides a method for manufacturing an extrusion printhead as described above, comprising the following steps: Select the printhead body according to the printing task requirements; The shape and size of the discontinuous interface are designed based on the physicochemical properties of the printing ink and the printing flow rate. The microstructure processing method is selected based on the shape, size and processing accuracy requirements of the microstructure, and the required microstructure is processed on the extrusion channel at the end of the printhead body; Wetting control treatment is applied to the walls of the printhead body and the extrusion channel; The front end of the printhead body is assembled with the printing equipment to perform extrusion printing.

[0017] The present invention achieves the following technical effects compared to the prior art: This invention constructs a composite boundary with alternating stitching between a discontinuous solid wall and an air interface by processing a microstructure that penetrates the sidewall of the extrusion channel at the end of the printhead body. By directly reducing the solid wall of the printhead, the solid-liquid contact area between the printing ink and the wall is reduced, thereby lowering the extrusion friction resistance. By controlling the wettability of the wall and using the difference in wettability to generate a capillary pinning effect, the fluid material is locally confined at the air interface and extruded from the outlet at the end of the printhead, thereby improving printing stability, accuracy, and material adaptability. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an extrusion printhead structure in one embodiment of the present invention; Figure 2 This is a schematic diagram of an extrusion printhead structure in another embodiment of the present invention; Figure 3 This is a schematic diagram of a structure where the internal flow channel is a direct flow channel; Figure 4 for Figure 3 A cross-sectional view along the length of the extrusion printhead; Figure 5 for Figure 3 Cross-sectional view along the extrusion printhead; Figure 6 This is a schematic diagram of the structure when the internal flow channel is a conical flow channel; Figure 7 for Figure 6 A cross-sectional view along the length of the extrusion printhead; Figure 8 for Figure 6 Cross-sectional view along the extrusion printhead; Figure 9 This is a schematic diagram of the first possible shape of the gap; Figure 10 This is a schematic diagram of the second shape of the gap; Figure 11 This is a schematic diagram of the first possible shape of a micropore. Figure 12 This is a schematic diagram of the second shape of the micropore; Figure 13 This is a schematic diagram of the third shape of micropores; Figure 14 This is a schematic diagram of the three-dimensional structure of the extrusion printhead with a slit in the extrusion channel of the present invention. Figure 15 This is a schematic diagram of the three-dimensional structure of the extrusion printhead with micropores in the extrusion channel of the present invention. Figure 16 This is a schematic diagram of the three-dimensional structure of the extrusion printhead with a grid structure in the extrusion channel of the present invention. Figure 17 This is a schematic diagram illustrating a processing step of the microstructure of the extrusion printhead of the present invention; Figure 18 This is a schematic diagram of the wettability control process of the extrusion printhead of the present invention; Figure 19 This is a schematic diagram of the manufacturing process of the extrusion printhead of the present invention; Figure 20 This diagram illustrates the process of extrusion printing and bioprinting using the extrusion printhead of this invention.

[0020] In the diagram: 1-Air interface; 2-Solid wall; 21-Side wall; 22-Outer wall; 23-Inner wall; 3-Internal flow channel; 4-Print head flow channel outlet; 5-Print head flow channel inlet; 6-Printing ink; 7-Piston; 8-Substrate; 9-Deposited ink fibers. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The purpose of this invention is to provide an extrusion printhead and its manufacturing method to solve the problems existing in the prior art, reduce extrusion resistance, reduce shear stress damage to cells, and improve cell survival rate after cell bio-ink printing.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Existing extrusion printheads are typically made of plastic, metal, or glass. Their common characteristic is that the flow channel walls are closed, continuous solid interfaces. During extrusion, the bio-ink comes into contact with the solid wall, effectively confining the fluid. The resulting frictional resistance significantly hinders fluid flow within the flow channel. To address this issue, this invention provides an extrusion printhead, see reference [reference]. Figures 1-20 The system includes a printhead body and an extrusion channel. The first end of the printhead body is used to connect to the printing device. The extrusion channel is located at the end of the printhead body. The two ends of the extrusion channel have a printhead channel outlet 4 and a printhead channel inlet 5, respectively. The printhead channel inlet 5 is connected to the end of the printhead body. The wall of the extrusion channel has microstructures that penetrate the sidewall of the extrusion channel, forming a discontinuous solid wall 2 and an air interface 1, which constitute a periodically spaced boundary structure to form the required discontinuous interface. The discontinuous interface allows the fluid to contact only in specific areas such as the inner wall of the extrusion channel and the printhead outlet wall during the extrusion process, while forming a capillary barrier at the air interface 1 to prevent the fluid from spreading laterally or leaking, thus achieving a wettability confinement effect. The wall of the extrusion channel is treated with wettability control to form a hydrophilic, superhydrophilic, hydrophobic, or superhydrophobic state to achieve selective wetting and repulsion of the printing material, thereby achieving confinement and guided extrusion of the fluid at the air interface 1 of the discontinuous interface. This invention constructs a composite boundary where discontinuous solid walls 2 and air interfaces 1 are alternately stitched together by processing microstructures through the extrusion channel wall at the end of the printhead body. By directly reducing the solid walls 2 of the printhead, the solid-liquid contact area between the printing ink 6 and the wall is reduced, thus lowering the extrusion friction resistance. By controlling the wettability of the wall and using the difference in wettability to generate a capillary pinning effect, the fluid material is locally confined at the air interface 1 and extruded from the outlet at the end of the printhead, thereby improving printing stability, accuracy, and material adaptability. The printhead of this invention can print non-biological materials, such as ceramic slurries and conductive hydrogels, or biological materials, such as hydrogels, macromolecular materials, and growth factors, and can also print cell-carrying bio-inks.

[0025] In one embodiment, the internal flow channel 3 of the extrusion channel is a straight flow channel structure or a conical flow channel structure. When it is a conical flow channel structure, the extrusion channel is a constricted structure with a large printhead flow channel inlet 5 and a small printhead flow channel outlet 4. The cross-section of the extrusion channel is circular or polygonal.

[0026] In one embodiment, the printhead body and the extrusion channel are integrally formed to create the printhead, and the printhead body and the extrusion channel are made of plastic, metal, glass, or ceramic. The printhead of this embodiment can be assembled or formed based on the following types through secondary processing: commercial plastic printheads; metal flat-tipped printheads, such as stainless steel needles, titanium alloy needles, aluminum alloy needles, etc.; glass printheads for biomaterials, photocurable inks, etc.; and 3D printing integrally formed printheads.

[0027] The printhead of the present invention may be manufactured by any one or a combination of the following methods: 3D printing employs methods such as multi-material photopolymerization printing (DLP, SLA, etc.), selective laser melting (SLM), and fused deposition modeling (FDM) to integrally form the printhead body, extrusion channels, and microstructures.

[0028] Micromolding technology utilizes silicon molds or soft photolithography templates to replicate extrusion channels through PDMS molding, forming a printhead with microstructures, enabling low-cost, mass production.

[0029] The extrusion-stretching method involves first prefabricating a tubular matrix containing microstructures, and then forming extrusion channels through a stretching process. It is suitable for glass or thermoplastic materials.

[0030] Furthermore, depending on the application requirements, the printhead can be manufactured from the following materials: plastics (PEEK, PTFE, PPSU, etc.), which are resistant to chemical corrosion and suitable for bioprinting; metals, such as stainless steel and titanium alloys, which are resistant to high temperature and pressure and suitable for printing metal powders / ceramic pastes; glass, which is optically transparent and suitable for photopolymerization printing; ceramics, such as high-hardness and high-temperature resistant alumina and zirconium oxide materials; and flexible materials such as PDMS and silicone, which have good elasticity and are suitable for microfluidic integrated printheads.

[0031] In one embodiment, the microstructure is at least one of slits and micropores. In another embodiment, a mesh structure can also be designed, such that the microstructure is at least one of slits, micropores, and mesh structures. When the discontinuous solid wall 2 of the extrusion channel is cylindrical or conical, narrow slits are formed between the columns. The shape of the slits can be straight, wavy, or spiral, etc. When the microstructure is a micropore, micropores are processed on the wall of the extrusion channel, and their structure is circular, elliptical, polygonal, or arbitrary. The number of slits and micropores can be one, multiple, or arranged in an array. When the microstructure is a mesh structure, a mesh-like hole structure is processed on the wall of the extrusion channel, which improves the stiffness of the solid wall 2 and the fluid confinement function, and is suitable for high viscosity and low surface tension inks.

[0032] Discontinuous interfaces can be achieved through the following high-precision machining techniques: Laser cutting utilizes femtosecond lasers or CO2 lasers for processing and is suitable for metal, ceramic, and glass substrates.

[0033] Precision tooling involves machining on substrates such as metals and hard plastics using methods such as micro-milling and micro-drilling.

[0034] Ion beam etching (FIB) is used to process metal substrates.

[0035] Chemical etching uses photolithography and wet etching processes to create patterned gaps or micropores on glass or metal substrates.

[0036] 3D printing utilizes DLP photopolymerization printing and two-photon printing technologies to integrally form gaps or micropore structures.

[0037] In one embodiment, the wettability control treatment employs dip coating, spray coating, sputtering deposition, plasma treatment, chemical etching, or laser processing. Specifically, in dip coating, the printhead is immersed in a functional coating solution (such as a suspension of fluorosilane or SiO2 nanoparticles) to form a superhydrophilic or superhydrophobic layer. In spray coating, a nanoparticle solution or functional coating solution is sprayed using aerosol or ultrasonic spraying to deposit a hydrophilic or hydrophobic nanocoating on the extrusion channel wall. In sputtering deposition, functional thin films such as TiO2 or SiO2 are deposited using magnetron sputtering to control the wettability of the extrusion channel wall. In plasma treatment, oxygen plasma is used to enhance surface hydrophilicity and superhydrophilicity; fluorine plasma is used to enhance surface hydrophobicity. In chemical etching, acid / alkali etching is used to construct micro / nano rough structures on the extrusion channel wall, combined with low surface energy modification, to achieve superhydrophobicity. In laser processing, a laser is used to induce micro / nano structures on the extrusion channel wall, simultaneously changing the surface chemical state to achieve regional wettability patterning.

[0038] The present invention also provides a method for manufacturing the above-mentioned extrusion printhead, see reference. Figure 19 It includes the following steps: Select the printhead body according to the printing task requirements; Based on the physicochemical properties (viscosity, surface tension, etc.) of printing ink 6 and the printing flow rate, design the shape and size of the discontinuous interface; The microstructure processing method is selected based on the shape, size and processing accuracy requirements of the microstructure, and the required microstructure is processed on the extrusion channel at the end of the printhead body; Wetting control treatment is applied to the walls of the printhead body and the extrusion channel; The front end of the printhead body is assembled with the printing equipment to perform extrusion printing.

[0039] This invention can be used to print non-biological materials, such as ceramic slurries; conductive materials, including but not limited to conductive polymer inks, liquid metal gels, and carbon nanotube slurries; magnetic / optical functional materials, including but not limited to Fe3O4 magnetic slurries; smart responsive materials, including but not limited to thermosensitive hydrogels (PNIPAM), pH-responsive polyacrylic acid slurries, and shape memory polymers (SMP); and photosensitive resins, including but not limited to PEGDA. It can also be used to print biological materials, such as gelatin, GelMA, collagen, sodium alginate, fibrinogen, and other hydrogels; biocompatible macromolecular materials, including but not limited to PEGDA, Pluronic F127, polyacrylamide-gelatin interpenetrating network (PAAm-Gel) hydrogels; various cell growth factors; or cell-mixed bio-inks.

[0040] Example 1 refer to Figures 3-8 Based on the geometry of the printhead body, different slits or micropore arrays can be designed. In this embodiment, when the printhead is a cylindrical extrusion printhead with a constant cross-section, straight slits are machined on the wall of the extrusion channel, with a fan-shaped cross-section to expand the area of ​​the air interface 1. In this embodiment, when the printhead is a printhead with a rectangular extrusion channel with a constant cross-section, a micropore array is machined on the wall of the extrusion channel, with the micropores being elliptical in shape to optimize the air interface 1 ratio and extrusion resistance. Furthermore, a mesh structure can be machined on the wall of the extrusion channel to form a three-dimensional air interface 1 barrier to enhance the confinement capability of the fluid at the air interface 1.

[0041] Example 2 refer to Figure 17 The extrusion printhead in this embodiment can be manufactured using 3D printing in a single integrated process, or machined or laser-cut on commercially available plastic or metal needles. The 3D printing integrated manufacturing process involves designing the printhead model using 3D modeling software and selecting a high-precision 3D printer to manufacture the printhead. This method can process complex discontinuous interfaces, such as wavy slits and mesh structures, without requiring subsequent assembly. The precision cutting process involves directly using commercially available plastic or metal needles as the base material, and utilizing precision micro-milling, femtosecond laser, or micro-drilling techniques to machine slits or arrays of micropores at the needle exit end, forming a discontinuous wall structure.

[0042] Example 3 refer to Figure 18 In this embodiment, for extrusion printheads with discontinuous interfaces, superhydrophobic modification of the solid wall surface 2 of the printhead can be carried out by dip coating or spray coating. The superhydrophobic coating is only constructed in the specified area, while the internal flow channel 3 of the extrusion channel is retained in a hydrophilic / unmodified state, so as to achieve differentiated wetting control of the outside being hydrophobic and the inside being hydrophilic, and enhance the ability to confine and restrain the fluid.

[0043] The dipping coating process is as follows: A clean airflow is continuously introduced into the internal channel 3 of the extrusion channel to protect it and prevent the nanoparticle solution from penetrating the inner wall. The extrusion channel is then inserted into the superhydrophobic nanoparticle solution, with the liquid surface only contacting the sidewall 21 and outer wall 22 of the extrusion channel. The airflow protects the inner wall 23 of the extrusion channel from being wetted by the solution. The channel is then removed and dried, allowing the nanoparticles to deposit on the sidewall 21 and outer wall 22 of the extrusion channel to form a superhydrophobic coating. This process is repeated 2-3 times to ensure a superhydrophobic coating is formed on the sidewall 21 and outer wall 22.

[0044] The spraying process is as follows: A sacrificial medium, such as paraffin wax, is injected into the inner channel 3 of the extrusion channel. After the paraffin wax solidifies, it seals the inner wall. A superhydrophobic coating is sprayed onto the outer wall surface 22 of the extrusion channel, or it is treated with fluorine plasma and dried, repeated 2-3 times. The paraffin wax is then heated to melt and blown off, restoring the inner wall surface 23 to cleanliness, and forming a superhydrophobic layer on the side wall surface 21 and the outer wall surface 22.

[0045] Example 4 refer to Figure 20 This embodiment illustrates extrusion printing using the extrusion printhead proposed in this invention. The printing ink 6 can be a high-viscosity material such as ceramic slurry, conductive polymer, or smart responsive polymer, and can be extruded via pneumatic, piston, or screw extrusion. Appropriate parameters such as printing flow rate and printing speed are selected. The printing ink 6 is stacked on the substrate 8 to form the desired 2D or 3D structure and cross-linked via photocuring, thermocuring, or ionic methods.

[0046] Extrusion bioprinting can be performed using the extrusion printhead proposed in this invention. The printing ink 6 is a temperature-sensitive bio-ink, such as a mixture of low-temperature sensitive GelMA hydrogel and sodium alginate hydrogel, which is liquid at room temperature (~25°C) and rapidly gels at low temperature (4~8°C). The printing ink 6 can be squeezed and delivered to the extrusion channel of the printhead by the piston 7. The substrate 8 is a low-temperature platform, and the temperature of the low-temperature platform is maintained at 4~8°C. After printing onto the low-temperature platform, the printing ink 6 rapidly gels to form deposited ink fibers 9, stacking to form a biological tissue structure. The biological tissue structure can be subsequently cross-linked by ultraviolet light or Ca2+. 2+ Cross-linking forms stable biological tissues. Thermosensitive bio-inks can be mixed with cells for printing. Using the extrusion printhead proposed in this invention, it is expected to reduce shear stress within the printing ink fluid, reduce cell damage, and improve cell survival rate in high-speed, high-flow-rate cell-carrying extrusion bioprinting.

[0047] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. An extrusion printhead, characterized in that: include: A printhead body, the front end of which is used to connect to a printing device; as well as An extrusion channel is located at the end of the printhead body. The wall of the extrusion channel has microstructures that penetrate the sidewall of the extrusion channel to form a discontinuous interface. The wall of the extrusion channel is treated with wettability control to form a hydrophilic, superhydrophilic, hydrophobic or superhydrophobic state to achieve confinement and guided extrusion of fluid at the air interface of the discontinuous interface.

2. The extrusion printhead according to claim 1, characterized in that: The internal flow channel shape of the extrusion channel is a straight flow channel structure or a conical flow channel structure; the cross-section of the extrusion channel is circular or polygonal.

3. The extrusion printhead according to claim 1, characterized in that: The printhead body and the extrusion channel are integrally formed, and the printhead body and the extrusion channel are made of plastic, metal, glass or ceramic.

4. The extrusion printhead according to claim 1, characterized in that: The microstructure is a slit and / or a micropore; the slit and / or micropore is made by laser cutting, tool processing, ion beam etching, chemical etching or 3D printing.

5. The extrusion printhead according to claim 4, characterized in that: When the extrusion channel wall has slits, a plurality of slits are arranged circumferentially on the side wall of the extrusion channel; the shape of the slits is straight, wavy or spiral.

6. The extrusion printhead according to claim 4, characterized in that: When the extrusion channel wall is provided with micropores, a plurality of micropores are arranged circumferentially on the side wall of the extrusion channel; the shape of the micropores is circular, elliptical or polygonal.

7. The extrusion printhead according to claim 4, characterized in that: When the extrusion channel wall is provided with micropores, multiple sets of hole groups are arranged circumferentially on the side wall of the extrusion channel, and each hole group includes multiple micropores arranged along the axial direction of the extrusion channel; the shape of the micropores is circular, elliptical or polygonal.

8. The extrusion printhead according to claim 4, characterized in that: When the wall of the extrusion channel is provided with micropores and slits, the micropores and slits are arranged at intervals along the circumference of the extrusion channel.

9. The extrusion printhead according to claim 1, characterized in that: The wettability control treatment is performed by dipping, spraying, sputtering, plasma treatment, chemical etching, or laser processing.

10. A method for manufacturing an extrusion printhead as described in any one of claims 1 to 9, characterized in that: Includes the following steps: Select the printhead body according to the printing task requirements; The shape and size of the discontinuous interface are designed based on the physicochemical properties of the printing ink and the printing flow rate. The microstructure processing method is selected based on the shape, size and processing accuracy requirements of the microstructure, and the required microstructure is processed on the extrusion channel at the end of the printhead body; Wetting control treatment is applied to the walls of the printhead body and the extrusion channel; The front end of the printhead body is assembled with the printing equipment to perform extrusion printing.

Images