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—The preparation of zinc sulfide nanoparticles by chemical deposition was studied. The thermal behavior of the thus-prepared nanopowder in air at temperatures in the range 25–500°C was examined by simultaneous thermal analysis. The product was identified using X-ray powder diffraction and IR spectroscopy. Transmission electron microscopy (TEM) was used to determine the sizes of the product nanoparticles. Functional ink based on the prepared zinc sulfide was used to form thick-film ZnS nanostructures by microextrusion printing. Scanning electron microscopy was used to study the microstructure of the thus-formed coatings, and their electrophysical properties were assessed by impedance spectroscopy. Microextrusion printing was found to be effective not only in bioprinting, but also in the formation of semiconductor coatings.

To establish an ideal microenvironment for regenerating maxillofacial defects, recent research interests have concentrated on developing scaffolds with intricate configurations and manipulating the stiffness of extracellular matrix toward osteogenesis. Herein, we propose to infuse a degradable RGD-functionalized alginate matrix (RAM) with osteoid-like stiffness, as an artificial extracellular matrix, to a rigid 3D-printed hydroxyapatite scaffold for maxillofacial regeneration. The 3D-printed hydroxyapatite scaffold was produced by microextrusion technology and showed good dimensional stability with consistent microporous detail. RAM was crosslinked by calcium sulfate to manipulate the stiffness, and its degradation was accelerated by partial oxidation using sodium periodate. The results revealed that viability of bone marrow stem cells was significantly improved on the RAM and was promoted on the oxidized RAM. In addition, the migration and osteogenic differentiation of bone marrow stem cells were promoted on the RAM with osteoid-like stiffness, specifically on the oxidized RAM. The in vivo evidence revealed that nonoxidized RAM with osteoid-like stiffness upregulated osteogenic genes but prevented ingrowth of newly formed bone, leading to limited regeneration. Oxidized RAM with osteoid-like stiffness facilitated collagen synthesis, angiogenesis, and osteogenesis and induced robust bone formation, thereby significantly promoting maxillofacial regeneration. Overall, this study supported that in the stabilized microenvironment, oxidized RAM with osteoid-like stiffness offered requisite mechanical cues for osteogenesis and an appropriate degradation profile to facilitate bone formation. Combining the 3D-printed hydroxyapatite scaffold and oxidized RAM with osteoid-like stiffness may be an advantageous approach for maxillofacial regeneration.

This paper presents a hybrid additive manufacturing (3D Printing) process for fabricating functionally gradient materials. A multi-axis robot was integrated with microextrusion, picojet, and fiber laser systems to deposit conductive traces of different materials. Laser and furnace curing mechanisms were investigated to evaluate their effect on grain morphology and electrical resistivity of the traces. An increase in the number of laser passes resulted in microstructure evolution from a powder-like to densely packed structure for different materials (Ag, Ni, and C). The laser curing mechanism offered lower resistivity and rapid curing times ( 2 h). Optimal sintering parameters were obtained for 4-pass laser at 18 W with comparable resistivity with bulk materials. Localized infiltration (doping) of nanoparticle silver within the micro-extruded carbon trace demonstrated a significant enhancement in electrical properties (two orders of magnitude reduction in resistivity). The energy dispersive x-ray spectroscopy (EDS) mapping of the infiltrated traces displayed uniform dispersion of nano-particulate silver within the carbon matrix. Multilayer-multi-material (MLMM) traces deposited displayed distinctive morphology of each constituent material based on in situ laser curing. Scanning electron microscopy revealed distinctive microstructure and graded elemental composition of different layers (FGM) based on targeted laser sintering of individual materials. The versatile hybrid AM platform provides a basis to fabricate functionally gradient materials (FGMs) for electronic components with several applications.

The interfacial friction between tool and workpiece is unpredictable in the micromanufacturing process. It has a major influence on process workability, which determines product formability. In this study, the microtribological behavior of MgO–ZnO mixed metal oxide nanoadditive lubricant with dry friction is investigated in the microextrusion process. In the microextrusion of aluminum 6063 gear, the extrusion force reduced significantly upon using the nanoadditive lubricant. The surface roughness result shows the improved surface quality due to the existence of nanoadditives in the micromanufacturing process. The quantitative deviation due to interfacial friction is resolved with different coefficients by performing the numerical evaluation. This research contributes to the fundamental understanding about the tribological and mechanical behavior of nanoadditive lubricant in the microextrusion process and facilitates in minimizing the interfacial friction.

Essential features of well-designed materials intended for 3D bioprinting via microextrusion are the appropriate rheological behavior and cell-friendly environment. Despite the rapid development, few materials are utilizable as bioinks. The aim of our work was to design a novel cytocompatible material facilitating extrusion-based 3D printing while maintaining a relatively simple and straightforward preparation process without the need for harsh chemicals or radiation. Specifically, hydrogels were prepared from gelatines coming from three sources-bovine, rabbit, and chicken-cross-linked by dextran polyaldehyde. The influence of dextran concentration on the properties of hydrogels was studied. Rheological measurements not only confirmed the strong shear-thinning behavior of prepared inks but were also used for capturing cross-linking reaction kinetics and demonstrated quick achievement of gelation point (in most cases < 3 min). Their viscoelastic properties allowed satisfactory extrusion, forming a self-supported multi-layered uniformly porous structure. All gelatin-based hydrogels were non-cytototoxic. Homogeneous cells distribution within the printed scaffold was confirmed by fluorescence confocal microscopy. In addition, no disruption of cells structure was observed. The results demonstrate the great potential of the presented hydrogels for applications related to 3D bioprinting., RP/CPS/2022/001; CZ.02.2.69/0.0/0.0/19_073/0016941; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: CZ.1.05/2.1.00/19.0376, RP/CPS/2022/003; Grantová Agentura České Republiky, GA ČR: 20-28732S, Ministry of Education, Youth and Sports of the Czech republic-DKRVO [RP/CPS/2022/003, RP/CPS/2022/001]; project OP RDE Junior Grants of TBU in Zlin [CZ.02.2.69/0.0/0.0/19_073/0016941]; CEBIA-Tech Instrumentation [CZ.1.05/2.1.00/19.0376]; Czech Science FoundationGrant Agency of the Czech Republic [20-28732S]

Highly viscous bioinks offer great advantages for the three-dimensional fabrication of cell-laden constructs by microextrusion printing. However, no standardised method of mixing a high viscosity biomaterial ink and a cell suspension has been established so far, leading to non-reproducible printing results. A novel method for the homogeneous and reproducible mixing of the two components using a mixing unit connecting two syringes is developed and investigated. Several static mixing units, based on established mixing designs, were adapted and their functionality was determined by analysing specific features of the resulting bioink. As a model system, we selected a highly viscous ink consisting of fresh frozen human blood plasma, alginate, and methylcellulose, and a cell suspension containing immortalized human mesenchymal stem cells. This bioink is crosslinked after fabrication. A pre-crosslinked gellan gum-based bioink providing a different extrusion behaviour was introduced to validate the conclusions drawn from the model system. For characterisation, bioink from different zones within the mixing device was analysed by measurement of its viscosity, shape fidelity after printing and visual homogeneity. When taking all three parameters into account, a comprehensive and reliable comparison of the mixing quality was possible. In comparison to the established method of manual mixing inside a beaker using a spatula, a significantly higher proportion of viable cells was detected directly after mixing and plotting for both bioinks when the mixing unit was used. A screw-like mixing unit, termed “HighVisc”, was found to result in a homogenous bioink after a low number of mixing cycles while achieving high cell viability rates.

Micro scale deformational behavior of metals is improved upon increasing the room temperature. Further, the drawbacks of micro forming caused by size effects are reduced significantly. In the current work, investigation on the material behavior of copper at elevated temperature ranging from room temperature to 200 ℃ is conducted. On the experimental part, a novel micro extrusion die set assembly has been developed along with temperature assistance, where the specimen is heated within the die assembly to study deformation behavior. When the forming temperature is raised, an enlargement of the forming limits is achieved along with a significant reduction in extrusion force. Further, the flow of material inside the die orifice was more uniform, and the micro pin showed a good replication of the die dimensions with homogeneous material deformation. During the increase of extrusion temperature and lubrication conditions (diamond-like carbon coating), the micro pin is more complete with higher dimensional accuracy and surface finish. The investigation on the influence of temperature showed that there is a reduction in microhardness of samples compared to the hardness of samples extruded at room temperature. However, there is a significant reduction of scattering due to homogenizing effect.

Ni-alumina-based catalysts were directly 3D printed into highly adaptable monolithic/multi-channel systems and evaluated for CO2 methanation. By employing emerging 3D printing technologies for catalytic reactor design such as 3D fibre deposition (also referred to as direct write or microextrusion), we developed optimised techniques for tailoring both the support’s macro- and microstructure, as well as its active particle precursor distribution. A comparison was made between 3D printed commercial catalysts, Ni-alumina based catalysts and their conventional counterpart, packed beds of beads and pellet. Excellent CO2 conversions and selectivity to methane were achieved for the 3D printed commercial catalyst (95.75% and 95.63% respectively) with stability of over 100 h. The structure-activity relationship of both the commercial and in-house 3D printed catalysts was explored under typical conditions for CO2 hydrogenation to CH4, using operando ‘chemical imaging’, namely X-Ray Diffraction Computed Tomography (XRD-CT). The 3D printed commercial catalyst showed a more homogenous distribution of the active Ni species compared to the in-house prepared catalyst. For the first time, the results from these comparative characterisation studies gave detailed insight into the fidelity of the direct printing method, revealing the spatial variation in physico-chemical properties (such as phase and size) under operating conditions.

Anode ridge structures are fabricated by printing anode pastes having different rheological properties to increase the electrode–electrolyte interfacial area in anode-supported solid oxide fuel cells. Homogeneous anode pastes are prepared by varying solid loadings, then their rheological characteristics are evaluated. It is confirmed that the shear stress at the same shear rate increases with increasing solid loading. The prepared pastes are printed onto flat anode substrates and then the width and height of the printed pastes are observed before and after drying and after sintering. As increasing solid loading in the paste, not only the width and height become smaller and larger, respectively, but also the shrinkage rate of the aspect ratio becomes smaller. Consequently, a large extension of the interfacial area of about 285% is obtained by printing the paste with the solid loading of 80%., [Solid Oxide Fuel Cells 16 - SOFC-XVI] September 8, 2019 - September 13, 2019 (Kyoto, Japan)

The objective of this study is to investigate the underlying physical phenomena behind material transport in pneumatic micro-extrusion (PME) process, using a computational fluid dynamics (CFD) model. The geometry of the PME deposition head assembly (including a micro-capillary having a diameter of 200 μm) was set up in the ANSYS-Fluent environment, based on a patented design in addition to direct measurements of the dimensions of the assembly. Subsequently, the geometry was meshed using tetrahedron cells. Besides, five layers of inflation were defined with the aim to obtain an accurate solution near all wall boundaries. The transient, pressure-based Navier-Stokes algorithm (based on absolute velocity formulation) was the mathematical model of choice, used to obtain transient solutions. To account for the effects of compressibility as well as viscose heating, the energy equation (in addition to the continuity and momentum equations) was utilized in the CFD model. Furthermore, the explicit volume of fluid model (composed of two Eulerian phases) and the laminar viscose model were used to collectively establish a viscose two-phase flow model for the molten polymer (PCL) deposition in the PME process. Pressure-velocity coupling was implemented using the semi-implicit method for pressure linked equations (SIMPLE). Finally, experimental sensor data was used with the aim to: (i) define the boundary conditions (as follows), and (ii) validate the CFD model. In this study, PCL powder was loaded into the cartridge, maintained at 120 °C, defined as the temperature of all stationery walls (with no slip condition). Pressure inlet was the type of boundary defined for the high-pressure gas flow in the PME process, set at 550 kPa. The laminar molten PCL flow was deposited on a glass substrate, steadily and uniformly kept at 45 °C, defined as the temperature of the substrate wall, moving with a speed of 0.35 mm/s. Overall, the results of this study pave the way for better understanding of the causal phenomena behind material transport and deposition in the PME process toward fabrication of bone tissue scaffolds with optimal functional properties.

Pneumatic micro-extrusion (PME), a direct-write additive manufacturing process, has emerged as a high-resolution method for the fabrication of a broad range of biological tissues and organs. However, the PME process is intrinsically complex, governed by complex physical phenomena. Hence, investigation of the effects of consequential parameters would be an inevitable need. The goal of this research work is to fabricate biocompatible, porous bone tissue scaffolds for the treatment of osseous fractures, defects, and eventually diseases. In pursuit of this goal, the objective of this study is to investigate the influence of material deposition factors — i.e., (i) deposition head temperature, (ii) flow pressure, and (iii) infill pattern — on the mechanical performance of PME-fabricated bone scaffolds. It was observed that the deposition head temperature as well as the flow pressure significantly affected scaffold diameter (unlike scaffold height). In addition, material deposition rate increased significantly as a result of an increase in the deposition temperature; this phenomenon stems from a reduction in Polycaprolactone (PCL) viscosity. Furthermore, there was a direct correlation between the amount of deposited mass and scaffold stiffness. Overall, the results of this study pave the way for future investigation of PME-deposited PCL scaffolds with optimal functional properties for incorporation of stem cells toward the treatment of osseous fractures and defects.

Pneumatic MicroExtrusion (PME) is a direct-write additive manufacturing process, which has emerged as a robust, high-resolution method for the fabrication of a broad spectrum of biological tissues and organs. However, the PME process is intrinsically complex, governed by bio-physio-chemical phenomena as well as material-process interactions. Hence, investigation of the influence of consequential factors on bone scaffold fabrication as well as investigation of cell-scaffold interactions would be an inevitable need. The objective of the work is to investigate the biocompatibility as well as the histological properties of PME-fabricated porous bone scaffolds, composed of polycaprolactone (PCL). To achieve this objective, a media extraction of the scaffold material was tested for cytostatic or cytotoxic activity with the aim to: (i) assess the fabricated scaffolds’ feasibility of use in regenerative medicine, and (ii) determine their structural integrity in a modelled in-vivo environment. In addition, the scaffolds were inoculated with an established osteosarcoma cell line (SAOS-2) and cultured for seven days to investigate the scaffold architecture and cell integration potential. A histological examination was performed on the seeded scaffolds for further in-depth analysis of cell-scaffold interaction. Overall, the results of this study pave the way for future investigation of stem cell incorporation into PME-fabricated PCL scaffolds toward the treatment of osseous fractures and defects.

Flowrate control has been a continuous challenge in Direct-Write Additive Manufacturing (DW AM) due to capacitive energy storage in the system and the lack of suitable flowrate sensors at the microscale, resulting in poor dimensional control of material addition. While a pressure sensor can be used for pressure-based feedback control, the system will become marginally stable if the material loses contact with the pressure sensor, and thus feedback is lost. In this letter, we design and implement a pressure-based hybrid controller with a state-dependent switching strategy that eliminates the stability problem due to a loss of pressure feedback, and thus enables the real time, stable control of flowrate in DW AM. The stability of the hybrid controller is assessed using phase portraits and Multiple Lyapunov-like Functions. The hybrid dynamical model and the hybrid controller are experimentally implemented and validated. Stability results indicate that the hybrid controller resolved the marginal stability issue, and is stable in the sense of Lyapunov. Moreover, the hybrid control scheme implementation in the case study demonstrated that the shape fidelity of the parts is appreciably enhanced compared to the open loop control case.

Microextrusion bioprinting has been used to recreate the complex architecture and composition of a physiological system through the quick and accurate handling of various biomaterials. However, existing techniques are limited in precisely fabricating complex constructs, including multilayers and heterogeneous patterns with distinct regions, because the extruded bioink spreads rapidly upon contact with the substrate and is partially mixed with subsequently printed bioinks. This issue leads to difficulties in accurately and stably constructing multi-material structures with clear interfaces for prolonged printing before gelation. To fabricate multilayered and heterogeneous constructs, a bioprinting system should be able to continuously extrude various biomaterials and simultaneously crosslink the extruded bioink to stabilize the printed construct. In this study, a multiple-bioink printing system was developed by integrating a multibarrel nozzle for extruding multiple bioinks with a nebulizer for simultaneous crosslinking. The crosslinking aerosol sprayed from the nebulizer was able to gelate the various hydrogel bioinks as they were extruded through the multibarrel nozzle. Such aerosol-based crosslinking improved printing resolution and stability. The developed bioprinting system showed the possibility of recapitulating the physiological complex architecture such as a cancer microenvironment with well-defined interfaces between regions of different mechanical properties and cellular compositions. Using the integrated bioprinting system, a multilayered and heterogeneous construct was printed with four bioinks, including three types of cells (breast cancer cells, stromal cells, and vascular endothelial cells). The printed biological model was characterized by analyzing cancer cell migration and vascular network formation. The developed multiple-bioink printing system is expected to be highly efficient in recapitulating complex tissues and their environments with compartmentalized regions.

Intercellular interaction is the most crucial factor in promoting cell viability and functionality in an engineered tissue system. Of the various shapes available for cell-laden constructs, spheroidal multicellular microarchitectures (SMMs) have been introduced as building blocks and injectable cell carriers with substantial cell-cell and cell-extracellular matrix (ECM) interactions. Here, we developed a precise and expeditious SMM printing method that can create a tissue-specific microenvironment and thus be potentially useful for cell therapy. This printing strategy is designed to manufacture SMMs fabricated with optimal bioink blended with decellularized ECM and alginate to enhance the functional performance of the encapsulated cells. Experimental results showed that the proposed method allowed for size controllability and mass production of SMMs with high cell viability. Moreover, SMMs co-cultured with endothelial cells promoted lineage-specific maturation and increased functionality compared to monocultured SMMs. Overall, it was concluded that SMMs have the potential for use in cell therapy due to their high cell retention and proliferation rate compared to single-cell injection, particularly for efficient tissue regeneration after myocardial infarction. This study suggests that utilizing microextrusion-based 3D bioprinting technology to encapsulate cells in cell-niche-standardized SMMs can expand the range of possible applications.

This paper investigated key factors influencing energy consumption in the microextrusion process. The considered factors were: extrusion ratio (ER), die angle (α), billet length (BL), bearing length (LB), coefficient of friction (COF), and die shift (DS). The finite element simulation was carried out to determine the extrusion energy required to complete one extrusion cycle. The simulation results showed that the increased values of all the considered factors (except the die shift) led to increased extrusion energy. The results also provided percentages of energy variation in steps, which helped evaluate the energy savings with regards to the crucial other production considerations. The percentage increase in energy consumption in the lower ER values was considered higher than those of, the higher ER values. Increasing die angle (α) from 60 to 90 deg barely affected the consumed energy. The highest increase percentage of extrusion energy was found while increasing billet lengths (BL) from 3.00 mm to 4.00 mm. The lower bearing length (LB) values offered lower consumed energy. The consumed extrusion energy linearly increased with COF. The die shift (DS) did not affect the extrusion energy, but the final part geometry (curved pins). The results and analysis from this study could be used to potential energy savings and overall production costs of the microextrusion process.

One of the challenges in 3D-bioprinting is the realization of complex, volumetrically defined structures, that are also anatomically accurate and relevant. Towards this end, in this study we report the development and validation of a carboxylated agarose (CA)-based bioink that is amenable to 3D printing of free-standing structures with high stiffness at physiological temperature using microextrusion printing without the need for a fugitive phase or post-processing or support material (FRESH). By blending CA with negligible amounts of native agarose (NA) a bioink formulation (CANA) which is suitable for printing with nozzles of varying internal diameters under ideal pneumatic pressure was developed. The ability of the CANA ink to exhibit reproducible sol-gel transition at physiological temperature of 37 °C was established through rigorous characterization of the thermal behavior, and rheological properties. Using a customized bioprinter equipped with temperature-controlled nozzle and print bed, high-aspect ratio objects possessing anatomically-relevant curvature and architecture have been printed with high print reproducibility and dimension fidelity. Objects printed with CANA bioink were found to be structurally stable over a wide temperature range of 4 °C to 37 °C, and exhibited robust layer-to-layer bonding and integration, with evenly stratified structures, and a porous interior that is conducive to fluid transport. This exceptional layer-to-layer fusion (bonding) afforded by the CANA bioink during the print obviated the need for post-processing to stabilize printed structures. As a result, this novel CANA bioink is capable of yielding large (5–10 mm tall) free-standing objects ranging from simple tall cylinders, hemispheres, bifurcated ‘Y’-shaped and ‘S’-shaped hollow tubes, and cylinders with compartments without the need for support and/or a fugitive phase. Studies with human nasal chondrocytes showed that the CANA bioink is amenable to the incorporation of high density of cells (30 million/mL) without impact on printability. Furthermore, printed cells showed high viability and underwent mitosis which is necessary for promoting remodeling processes. The ability to print complex structures with high cell densities, combined with excellent cell and tissue biocompatibility of CA bodes well for the exploitation of CANA bioinks as a versatile 3D-bioprinting platform for the clinical translation of regenerative paradigms.

Three-dimensional (3D) bioprinting promises to be essential in tissue engineering for solving the rising demand for organs and tissues. Some bioprinters are commercially available, but their impact on the field of Tissue engineering (TE) is still limited due to their cost or difficulty to tune. Herein, we present a low-cost easy-to-build printhead for microextrusion-based bioprinting (MEBB) that can be installed in many desktop 3D printers to transform them into 3D bioprinters. We can extrude bioinks with precise control of print temperature between 2&ndash, 60 &deg, C. We validated the versatility of the printhead, by assembling it in three low-cost open-source desktop 3D printers. Multiple units of the printhead can also be easily put together in a single printer carriage for building a multi-material 3D bioprinter. Print resolution was evaluated by creating representative calibration models at different temperatures using natural hydrogels such as gelatin and alginate, and synthetic ones like poloxamer. Using one of the three modified low-cost 3D printers, we successfully printed cell-laden lattice constructs with cell viabilities higher than 90% after 24-h post printing. Controlling temperature and pressure according to the rheological properties of the bioinks was essential in achieving optimal printability and great cell viability. The cost per unit of our device, which can be used with syringes of different volume, is less expensive than any other commercially available product. These data demonstrate an affordable open-source printhead with the potential to become a reliable alternative to commercial bioprinters for any laboratory.

3D bioprinting of living cellular constructs with heterogeneity in cell types and extra cellular matrices (ECMs) matching those of biological tissues remains challenging. Here, we demonstrate that, through bioink material design, microextrusion-based (ME) bioprinting techniques have the potential to address this challenge. A new bioink employing alginate (1%), cellulose nanocrystal (CNC) (3%), and gelatin methacryloyl (GelMA) (5%) (namely 135ACG hybrid ink) was formulated for the direct printing of cell-laden and acellular architectures. The 135ACG ink displayed excellent shear-thinning behavior and solid-like properties, leading to high printability without cell damage. After crosslinking, the ACG gel can also provide a stiff ECM ideal for stromal cell growth. By controlling the degree of substitution and polymer concentration, a GelMA (4%) bioink was designed to encapsulate hepatoma cells (hepG2), as GelMA gel possesses the desired low mechanical stiffness matching that of human liver tissue. Four different versions of to-scale liver lobule-mimetic constructs were fabricated via ME bioprinting, with precise positioning of two different cell types (NIH/3T3 and hepG2) embedded in matching ECMs (135ACG and GelMA, respectively). The four versions allowed us to exam effects of mechanical cues and intercellular interactions on cell behaviors. Fibroblasts thrived in stiff 135ACG matrix and aligned at the 135ACG/GelMA boundary due to durotaxis, while hepG2 formed spheroids exclusively in the soft GelMA matrix. Elevated albumin production was observed in the bicellular 3D co-culture of hepG2 and NIH/3T3, both with and without direct intercellular contact, indicating that improved hepatic cell function can be attributed to soluble chemical factors. Overall, our results showed that complex constructs with multiple cell types and varying ECMs can be bioprinted and potentially useful for both fundamental biomedical research and translational tissue engineering.

Bioprinting is a rapidly expanding technology with the ability to fabricate in vitro three-dimensional (3D) tissues in a layer-by-layer manner to ultimately produce a living tissue which physiologically resembles native in vivo tissue functionality. Unfortunately, large costs associated with commercially available bioprinters severely limit access to the technology. We investigated the potential for modifying a low-cost commercially available RepRap Prusa iteration 3 (i3) 3D printer with an open-source syringe-housed microextrusion print-head unit (universal paste extruder by Richard Horne, RichRap), that allowed for controlled deposition of cell-laden bioinks and Freeform Reversible Embedding of Suspended Hydrogels (FRESH) method-based printing., Graphical abstract Image, graphical abstract

As the market for minimally invasive surgery has grown, the demand for high-precision and high-performance catheters has increased. Catheters for the diagnosis and treatment of cardiovascular or cerebrovascular disease mainly use a braided wire tube with a polymer inner liner and outer jacket to improve the pushability and trackability. The outer jacket should have an accurate inner and outer diameter and while maintaining a wall thickness of 150 &micro, m or less. In this study, we designed and manufactured a tip and die capable of extruding an outer jacket with a wall thickness of 150 &micro, m or less using a medical thermoplastic elastomer for manufacturing 8Fr (2.64 mm diameter) thin-walled tubes. The ovality and inner/outer diameters of the tube were studied according to changes in the screw speed (mass flow rate), puller speed, air pressure applied to the lumen, and distance between the quench and head, which are the main variables of microextrusion processes. The screw speed (mass flow rate), puller speed, and air pressure affected the inner/outer diameter of the tube, with screw speed and puller speed having the largest influence on diameter. The air pressure and distance between quench and head had the greatest influence on ovality. The results show the effect of different processing parameters on the characteristics of the extruded tube, which will help to establish a stable extrusion process for the manufacture of outer jackets for braided catheter shafts.