Research on Inner Gas Inflation Improvements in Double-layer Gas-assisted Extrusion of Micro-tubes

Luo, Cheng; Huang, Xingyuan; Liu, Tongke; Liu, Hesheng

doi:10.3390/polym12040899

Cited by 9 publications

(6 citation statements)

References 24 publications

(23 reference statements)

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“…In this study, the coextruded product studied was a striped single-lumen catheter, as shown in Figure 1 [ 6 , 28 ], which had an external diameter of 1.10 ± 0.01 mm, an inner diameter of 0.80 mm ± 0.03 mm, and a wall thickness of 0.15 mm. The main material used in this study was thermoplastic polyurethane (TPU, Lubrizol TPU2363-65D [ 29 ]), which was specially designed for medical material applications.…”

Section: Problem Definitions For the Coextrusionmentioning

confidence: 99%

Improved Optimization of a Coextrusion Die with a Complex Geometry Using the Coupling Inverse Design Method

2023

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The main challenge in a polymer coextrusion process is to have a good die design prior to the process, which can minimize the geometric errors that are caused by extrusion swell and interface motion. For this purpose, a coupling method of optimization and inverse design for a coextrusion die was studied for a medical striped catheter. In the study, the main material was thermoplastic polyurethane (TPU), and the auxiliary material was TPU filled with 30 wt% barium sulfate. An overall optimization design method was used to optimize the geometry of the extrusion die channel for the striped catheter, which had a complex geometry. In the global optimization process, the local inverse design method was used to design the inlet of the auxiliary material. The non-linear programming by quadratic Lagrangian (NLPQL) algorithm was used to obtain the optimal geometric solution of the coextrusion die runner. The experimental verification results showed that the coupling method for coextrusion die design improved the design efficiency of the coextrusion die remarkably. The value of the objective function, which was used to measure the geometric error of the product, was reduced by 72.3% compared with the initial die design.

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Section: Problem Definitions For the Coextrusionmentioning

confidence: 99%

Improved Optimization of a Coextrusion Die with a Complex Geometry Using the Coupling Inverse Design Method

2023

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“…[ 47 ] To overcome the problems of extrudate swelling (Figure 2c), melt fracture, and extrudate distortion, a modified gas‐assisted extrusion forming system, which generates gas lubrication at the mold wall, has been established to prepare polypropylene (PP) microtubes, which reduced melt pressure and energy consumption. [ 48,49 ] Notably, this technique was outperformed the conventional extrusion methods. As shown in Figure 2b, the outer diameter ( Φ = 5.0 mm), inner diameter, and wall thickness (δ = 0.8 mm) of PP microtubes prepared using the traditional extrusion method are considerably larger than those of PP microtubes prepared using gas‐assisted extrusion method ( Φ = 3.1 mm and δ = 0.48 mm).…”

Section: Micro/nanomoldingmentioning

confidence: 99%

Current and Future Trends for Polymer Micro/Nanoprocessing in Industrial Applications

et al. 2022

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Polymers are widely used in optical devices, electronic devices, energy‐harvesting/storage devices, and sensors, owing to their low weight, excellent flexibility, and simple fabrication process. With advancements in micro/nanoprocessing techniques and more demanding application requirements, it is becoming necessary to realize high‐resolution fabrication of polymers to prepare miniaturized devices. This is particularly because conventional processing technologies suffer from high thermal stress and strong adhesion/friction, which can irreversibly damage the micro/nanostructures of miniaturized devices. In addition, although the use of advanced fabrication methods to prepare high‐resolution micro/nanostructures is explored, these methods are limited to laboratory research or small‐batch production. This review focuses on the micro/nanoprocessing of polymeric materials and devices with high spatial precision and replication accuracy for industrial applications. Specifically, the current state‐of‐the‐art techniques and future trends for micro/nanomolding, high‐energy beam processing, and micro/nanomachining are discussed. Moreover, an overview of the fabrication and applications of various polymer‐based elements and devices such as microlenses, biosensors, and transistors is provided. These techniques are expected to be widely applied for multiscale and multimaterial processing as well as for multifunction integration in next‐generation integrated devices, such as photoelectric, smart, and biodegradable devices.

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“…The application of gas-assisted techniques in the extrusion of plastic micro-tubes can effectively tackle these challenges by transforming the molten material within the die from a viscous flow to a slip flow regime [24][25][26][27][28]. Liang [29] introduced the slit inlet method, which utilizes gas-assisted technology to create a stable air cushion between the mold and the polymer melt, resulting in a significant reduction in die resistance.…”

Section: Introductionmentioning

confidence: 99%

Influence of Gas Inlet Slit Width on Gas-Assisted Plastic Micro-Tube Extrusion

et al. 2023

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In the process of the double-layer gas-assisted extrusion of plastic micro-tubes, the external size and surface quality of the micro-tubes are greatly affected by the size of the assisting gas inlet slit inside the mold. Therefore, in this experiment, a two-phase flow model was established based on a compressible gas and a non-compressible melt. The Polyflow finite element solution software module was used to solve the velocity field, temperature field, pressure field, and section size of the melt under the condition of double-layer gas-assisted extrusion in a mold under different gas inlet slit widths. The results show that, with an increase in the width of the gas inlet slit, the melt outlet velocity increases, the surface temperature increases, wall thickness shrinkage increases, and interior diameter expansion increases. In the process of gas-assisted extrusion, the thickness of the air cushion is affected by adjusting the size of the gas inlet slit, and, hence, changes the shape and size of the plastic micro-tubes.

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Research on Inner Gas Inflation Improvements in Double-layer Gas-assisted Extrusion of Micro-tubes

Cited by 9 publications

References 24 publications

Improved Optimization of a Coextrusion Die with a Complex Geometry Using the Coupling Inverse Design Method

Improved Optimization of a Coextrusion Die with a Complex Geometry Using the Coupling Inverse Design Method

Current and Future Trends for Polymer Micro/Nanoprocessing in Industrial Applications

Influence of Gas Inlet Slit Width on Gas-Assisted Plastic Micro-Tube Extrusion

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