Micro-injection Molded Polymeric Surfaces for the Maintenance of Human Mesenchymal Stem Cells (hMSCs)

2013 ◽  
Vol 1499 ◽  
Author(s):  
Meghan E. Casey ◽  
John W. Rodgers ◽  
Courtney E. LeBlon ◽  
John P. Coulter ◽  
Sabrina S. Jedlicka
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Injection Molding ◽  
Silicon Wafer ◽  
Human Mesenchymal Stem Cells ◽  
Mold Insert ◽  
High Volume ◽  
Injection Molding Process ◽  
Molding Process ◽  
Micro Features

ABSTRACTIn this work, we take advantage of injection molding as a high volume and repeatable method to create surface areas for the growth of human mesenchymal stem cells (hMSCs). Ultraviolet lithography, combined with deep reactive ion etching, was used to generate micro-features over a relatively large surface area of a silicon wafer. The micro-featured silicon wafer was used as a mold insert for the micro-injection molding process to create polystyrene and low density polyethylene surfaces. Micro-geometry was used to alter the effective surface stiffness of the polymer substrate. Created samples were characterized via scanning electron microscopy and tensile testing. hMSCs were seeded onto samples for initial studies. Actin and vinculin were visualized through ICC to compare cytoskeletal elements. Changes in cell morphology were examined using ICC. Results indicate that injection molding of microfeatured substrates is a viable technique to produce surfaces amenable to stem cell growth.

scholarly journals Producing Hollow Polymer Microneedles Using Laser Ablated Molds in an Injection Molding Process

2021 ◽  
Author(s):  
Tim Evens ◽  
Lorenz Van Hileghem ◽  
Francesco Dal Dosso ◽  
Jeroen Lammertyn ◽  
Olivier Malek ◽  
...  
Keyword(s):  
Injection Molding ◽  
Large Scale ◽  
Low Cost ◽  
Mold Insert ◽  
High Volume ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Molding Process ◽  
Melt Temperature ◽  
Hollow Microneedles

Abstract Microneedle arrays contain needle-like microscopic structures which facilitate drug or vaccine delivery in a minimally invasive way. However, producing hollow microneedles is currently limited by expensive, time consuming and complex microfabrication techniques. In this paper, a novel method to produce hollow polymer microneedles is presented. This method utilizes a femtosecond laser to create hollow microneedle cavities in a mold insert. This mold insert is used in an injection molding process, to replicate polymethyl methacrylate microneedles. The combined effect of the mold temperature, volumetric injection rate and melt temperature on the replication fidelity was evaluated. It was found that the combination of high injection molding parameters facilitated the replication. Furthermore, the functionality of the manufactured hollow microneedles was successfully tested by injecting a controlled flow of colored water into an agarose matrix. The developed methodology enables the production of low-cost, high-volume microneedle devices, which could be a key asset for large scale vaccination campaigns.

scholarly journals Process influences and correction possibilities for high precision injection molded freeform optics

2016 ◽  
Vol 5 (4) ◽  
Author(s):  
Lars Dick ◽  
Stefan Risse ◽  
Andreas Tünnermann
Keyword(s):  
Injection Molding ◽  
High Precision ◽  
Influencing Factor ◽  
High Volume ◽  
Injection Molding Process ◽  
Molding Process ◽  
Shape Accuracy ◽  
Polymer Optics ◽  
Freeform Optics ◽  
Form Deviation

AbstractModern injection molding processes offer a cost-efficient method for manufacturing high precision plastic optics for high volume applications. Besides form deviation of molded freeform optics, internal material stress is a relevant influencing factor for the functionality of a freeform optics in an optical system. This paper illustrates dominant influence parameters of an injection molding process relating to form deviation and internal material stress based on a freeform demonstrator geometry. Furthermore, a deterministic and efficient way for 3D mold correcting of systematic, asymmetrical shrinkage errors is shown to reach micrometer range shape accuracy at diameters up to 40 mm. In a second case, a stress-optimized parameter combination using unusual molding conditions was 3D corrected to reach high precision and low stress freeform polymer optics.

scholarly journals Insights into the Processing of Recycled Carbon Fibers via Injection Molding Compounding

2020 ◽  
Vol 4 (4) ◽  
pp. 161
Author(s):  
Jochen Wellekötter ◽  
Julia Resch ◽  
Stephan Baz ◽  
Götz Theo Gresser ◽  
Christian Bonten
Keyword(s):  
Injection Molding ◽  
Matrix Material ◽  
High Strength ◽  
High Volume ◽  
Injection Molding Process ◽  
Fiber Reinforced ◽  
Feed System ◽  
Molding Process ◽  
Reinforced Plastics ◽  
Recycled Fibers

Although fiber-reinforced plastics combine high strength and stiffness with being lightweight, major difficulties arise with high volume production and the return of manufactured parts back into the cycle of materials at the end of their lifecycles. In a novel approach, structural parts were produced from recycled material while utilizing the so-called injection molding compounding process. Recycled fibers and recycled polyamide matrix material were used by blending carbon and matrix fibers into a sliver before processing. Injection molding was then used to produce long fiber-reinforced parts through a direct fiber feed system. Recycled matrix granules were incorporated into the injection molding process by means of an injection molding compounder to investigate their influences on the mechanical properties of the parts. The findings show that the recycled fibers and matrix perform well in standardized tests, although fiber length and fiber content vary significantly and remain below expectations.

Design and Experimental Validation of a Process Chain for Thin Components Manufacturing by Micro Injection Molding Process

2021 ◽  
Author(s):  
Vincenzo Bellantone ◽  
Fulvio Lavecchia ◽  
Rossella Surace ◽  
Onofrio Spadavecchia ◽  
Francesco Modica ◽  
...  
Keyword(s):  
Injection Molding ◽  
Rapid Development ◽  
Micro Milling ◽  
Surface Finishing ◽  
Injection Molding Process ◽  
Manufacturing Cost ◽  
Process Chain ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Micro Features

Abstract Micro applications, especially in biomedical and optical sectors, require the fabrication of thin polymeric parts which can be commonly realized by micro injection molding process. However, this process is characterized by a relevant constraint regarding the tooling. Indeed, the design and manufacturing of molds could be a very time-consuming step and so, a significant limitation for the rapid development of new products. Moreover, if the design displays challenging micro-features, their realization could involve the use of more than one mold for the fabrication of a single thin part. Therefore, a proper integration of different manufacturing micro technologies may represent an advantageous method to realise such polymeric thin micro features. In this work, a micro-manufacturing process chain including stereolithography, micro milling and micro injection molding is reported. The mold for the micro injection molding process was fabricated by means of stereolithography and micro milling, which allowed to produce low-cost reconfigurable modular mold, composed by an insert support and a removable insert. The assessment of the proposed process chain was carried out by evaluating the dimensions and the surface finishing and texturing of the milled mold cavities and molded components. Finally, a brief economic analysis compares three process chains for fabricating the micro mold showing that proposed one reduces manufacturing cost of almost 61% with the same production time.

scholarly journals Self-Assembled Monolayers of Alkanethiols on Nickel Insert: Characterization of Friction and Analysis on Demolding Quality in Microinjection Molding

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 636
Author(s):  
Jiachen Chen ◽  
Jin Yang ◽  
Mingyong Zhou ◽  
Can Weng
Keyword(s):  
Injection Molding ◽  
Surface Effect ◽  
Mold Insert ◽  
Self Assembled Monolayers ◽  
Injection Molding Process ◽  
Molding Process ◽  
Adhesion Properties ◽  
Assembled Monolayers ◽  
Self Assembled

When the part geometry scaling down from macro to microscale level, the size-induced surface effect becomes significant in the injection molding process. The adhesion between polymer and nickel (Ni) mold insert during the process can lead to defects in necking, warping and deformation of microstructure. In this study, the self-assembled monolayers (SAMs) with low surface energy were deposited on the Ni surface to reduce the adhesion and further improve the demolding quality of the microstructure. Results show that the alkyl mercaptan SAMs with chemical bonds and close alignment can be successfully deposited on the surface of Ni by the solution deposition method. The contact angle, surface free energy, and friction coefficient before and after anti-adhesion treatment on the surface of mold insert were measured. In addition, the anti-adhesion properties of different alkyl mercaptan materials and the correspondingly replication quality of microstructure parts after injection molding were analyzed. It is found that the Ni mold insert treated by the perfluorodecanethiol has the best wear resistance and still shows good reproducibility at the 100th demolding cycle.

scholarly journals Multi-Scale Simulation of Injection Molding Process with Micro–Features Replication: Relevance of Rheological Behaviour and Crystallization

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3236
Author(s):  
Sara Liparoti ◽  
Vito Speranza ◽  
Roberto Pantani ◽  
Giuseppe Titomanlio
Keyword(s):  
Injection Molding ◽  
Surface Properties ◽  
Low Temperatures ◽  
Rheological Behaviour ◽  
Cavity Surface ◽  
Injection Molding Process ◽  
Multiscale Approach ◽  
Molding Process ◽  
Micro Features ◽  
Replication Accuracy

The possibility of tailoring key surface properties through the injection molding process makes it intriguing from the perspective of sustainability enhancement. The surface properties depend on the replication accuracy of micro and nanostructures on moldings; such an accuracy is enhanced with cavity temperature. The simulation of the injection molding process is very challenging in the presence of micro and nanostructures on the cavity surface; this does not allow for the neglect of phenomena generally considered not to influence the overall process. In this paper, a multiscale approach was proposed: in the first step, the simulation of the overall process was conducted without considering the presence of the microstructure; in the second step the outputs of the first step were used as an input to simulate the replication of the microfeature. To this purpose, a lubrication approximation was adopted, and the contribution of the trapped air, which slows down the polymer advancement, was accounted for. A modification of the viscosity equation was also proposed to describe the rheological behavior of isotactic polypropylene at very low temperatures. Concerning the microcavity filling simulation, the modification of the viscosity description at low temperatures consistently describes the process, in terms of polymer solidification. Concerning the replication accuracy, it increases with the cavity surface temperature, consistently with the experimental observations.

Low-Energy Injection Molding Process by a Mold with Permeability Fabricated by Additive Manufacturing

2016 ◽  
Vol 10 (1) ◽  
pp. 101-105 ◽  
Author(s):  
Hiroshi Koresawa ◽  
◽  
Kohei Tanaka ◽  
Hiroyuki Narahara
Keyword(s):  
Additive Manufacturing ◽  
Injection Molding ◽  
Electric Energy ◽  
Mold Insert ◽  
Low Energy ◽  
Injection Molding Process ◽  
Molding Machine ◽  
Molding Process ◽  
Injection Process ◽  
Flow Length

This paper describes the improvement of flow length and realization of low-energy molding in the injection molding process, by focusing on the injection mold with permeability fabricated by additive manufacturing. The mold is equipped with a sintered body with permeability, which is used as a mold insert. The inside of the sintered mold insert is structured so that the permeability should not be degraded, even if the thickness is increased. With respect to the effect of the sintered mold insert with permeability, the flow length and low-energy molding are evaluated by the filling rate of a thin section of moldings, and the electric energy of the injection molding machine that drives the screw in the injection process. Through fundamental experiments, the mold using the sintered mold insert with permeability was found to improve the flow length. The electric energy of the injection molding machine in the injection process is reduced by 6%--13% compared with the sintered mold insert without permeability.

Innovations in Micro Metal Injection Molding Process by Lost Form Technology

2007 ◽  
Vol 534-536 ◽  
pp. 369-372 ◽  
Author(s):  
Kazuaki Nishiyabu ◽  
Yasuhiro Kanoko ◽  
Shigeo Tanaka
Keyword(s):  
Injection Molding ◽  
Mold Insert ◽  
Production Method ◽  
Metal Injection Molding ◽  
Injection Molding Process ◽  
Stainless Steel 316L ◽  
Molding Process ◽  
Debinding Process ◽  
Micro Structures ◽  
Plastic Mold

The production method of micro sacrificial plastic mold insert metal injection molding, namely μ-SPiMIM process has been proposed to solve specific problems involving the miniaturization of MIM. The sacrificial plastic mold (SP-mold) with fine structures was prepared by injection-molding polymethylmethacrylate (PMMA) into Ni-electroform, which is a typical LIGA (Lithographie-Galvanoformung-Abformung) process. Stainless steel 316L feedstock was injectionmolded into the SP-mold which had micro structures with multi-pillars. The green compact was demolded as one component with the SP-mold, which was decomposed along with binder constituent of feedstock in debinding process. This study focused on the effects of metal particle size and processing conditions on the shrinkage, transcription and surface roughness of sintered parts, which were evaluated by SEM (Scanning Electron Microscope) observation.

Computational Study of the Effect of Governing Parameters on a Polymer Injection Molding Process for Single-Cavity and Multicavity Mold Systems

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
M. Tutar ◽  
A. Karakus
Keyword(s):  
Injection Molding ◽  
Mold Insert ◽  
Polymer Melt ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Conditions ◽  
Molding Process ◽  
Polymer Injection ◽  
Solution Approach ◽  
Polymer Injection Molding

In the present study a more complete numerical solution approach using parallel computing technology is provided for the three-dimensional modeling of mold insert polymer injection molding process by considering the effects of phase-change and compressibility for non-Newtonian fluid flow conditions. A volume of fluid (VOF) method coupled with a finite volume approach is used to simulate the mold-filling stage of the injection molding process. The variations in viscosity and density in the polymer melt flow are successfully resolved in the present VOF method to more accurately represent the rheological behavior of the polymer melt flow during the mold filling. A comprehensive high-resolution differencing scheme (compressive interface capturing scheme for arbitrary meshes or CICSAM) is successfully utilized to capture moving interfaces and the pressure-implicit with splitting operators pressure-velocity coupling algorithm is employed to enable a higher degree of approximate relation between corrections for pressure and velocity. The capabilities of the proposed numerical methodology in modeling real molding flow conditions are verified through quantitative and qualitative comparisons with other simulation programs and the data obtained from the experimental study conducted. The present numerical results are also compared with each other for a polypropylene female threaded adaptor pipe fitting model with a metallic insert for varying governing process conditions/parameters to assess the modeling constraints and enhancements of the present numerical procedure and the effects of these conditions to optimize the polymer melt flow for mold insert polymer injection molding process. The numerical results suggest that the present numerical solution approach can be used with a confidence for further studies of optimization of design of mold insert polymer injection molding processes.

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