Comparisons of Different Elastomer Micro Molds

2012 ◽  
Vol 591-593 ◽  
pp. 997-1000
Author(s):  
Hang Liu ◽  
Yan Xu ◽  
Chun Lei Kang ◽  
Kai Leung Yung ◽  
Wei Chen
Keyword(s):  
High Temperature ◽  
Carbon Nanotube ◽  
Injection Molding ◽  
Mold Insert ◽  
Micro Injection Molding ◽  
Rubber Sheet ◽  
Silicon Rubber ◽  
Micro Features

This paper demonstrates the comparisons of molding with micro molds made of different elastomeric polymers. Micro molds made of pure polydimethylsiloxane (PDMS), 0.3% carbon nanotube (CNT) enforced polydimethylsiloxane (PDMS), 2% carbon nanotube (CNT) enforced polydimethylsiloxane (PDMS) and commercial available high temperature silicon rubber sheet (Avon Group) were studied. Micro moldings using different molding pressures were performed. By comparing the dimensions of micro features produced with different molding pressures, molding accuracies of using micro molds made of different elastomeric polymers are obtained. Results of this study provide valuable information for the development of elastomer micro mold insert for micro injection molding.

scholarly journals Molecular Dynamics Simulation on the Influences of Nanostructure Shape, Interfacial Adhesion Energy, and Mold Insert Material on the Demolding Process of Micro-Injection Molding

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1573 ◽  
Author(s):  
Jin Yang ◽  
Can Weng ◽  
Jun Lai ◽  
Tao Ding ◽  
Hao Wang
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Injection Molding ◽  
Interfacial Adhesion ◽  
Mold Insert ◽  
Adhesion Energy ◽  
Dynamics Simulation ◽  
Micro Injection Molding ◽  
Interfacial Adhesion Energy

In micro-injection molding, the interaction between the polymer and the mold insert has an important effect on demolding quality of nanostructure. An all-atom molecular dynamics simulation method was performed to study the effect of nanostructure shape, interfacial adhesion energy, and mold insert material on demolding quality of nanostructures. The deformation behaviors of nanostructures were analyzed by calculating the non-bonded interaction energies, the density distributions, the radii of gyration, the potential energies, and the snapshots of the demolding stage. The nanostructure shape had a direct impact on demolding quality. When the contact areas were the same, the nanostructure shape did not affect the non-bonded interaction energy at PP-Ni interface. During the demolding process, the radii of gyration of molecular chains were greatly increased, and the overall density was decreased significantly. After assuming that the mold insert surface was coated with an anti-stick coating, the surface burrs, the necking, and the stretching of nanostructures were significantly reduced after demolding. The deformation of nanostructures in the Ni and Cu mold inserts were more serious than that of the Al2O3 and Si mold inserts. In general, this study would provide theoretical guidance for the design of nanostructure shape and the selection of mold insert material.

scholarly journals Investigation of Interface Thermal Resistance between Polymer and Mold Insert in Micro-Injection Molding by Non-Equilibrium Molecular Dynamics

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2409
Author(s):  
Can Weng ◽  
Jiangwei Li ◽  
Jun Lai ◽  
Jiangwen Liu ◽  
Hao Wang
Keyword(s):  
Heat Transfer ◽  
Molecular Dynamics ◽  
Injection Molding ◽  
Thermal Resistance ◽  
Mold Insert ◽  
Micro Injection Molding ◽  
Interface Resistance ◽  
Interface Thermal Resistance ◽  
Packing Pressure ◽  
Non Equilibrium Molecular Dynamics

Micro-injection molding has attracted a wide range of research interests to fabricate polymer products with nanostructures for its advantages of cheap and fast production. The heat transfer between the polymer and the mold insert is important to the performance of products. In this study, the interface thermal resistance (ITR) between the polypropylene (PP) layer and the nickel (Ni) mold insert layer in micro-injection molding was studied by using the method of non-equilibrium molecular dynamics (NEMD) simulation. The relationships among the ITR, the temperature, the packing pressure, the interface morphology, and the interface interaction were investigated. The simulation results showed that the ITR decreased obviously with the increase of the temperature, the packing pressure and the interface interaction. Both rectangle and triangle interface morphologies could enhance the heat transfer compared with the smooth interface. Moreover, the ITR of triangle interface was higher than that of rectangle interface. Based on the analysis of phonon density of states (DOS) for PP-Ni system, it was found that the mismatch between the phonon DOS of the PP atoms and Ni atoms was the main cause of the interface resistance. The frequency distribution of phonon DOS also affected the interface resistance.

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.

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 Micro-Injection Molding of Diffractive Structured Surfaces

2021 ◽  
Vol 5 (1) ◽  
pp. 12
Author(s):  
Ann-Katrin Boinski ◽  
Barnabas Adam ◽  
Arne Vogelsang ◽  
Lars Schönemann ◽  
Oltmann Riemer ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Performance ◽  
Mold Insert ◽  
Diamond Turning ◽  
Micro Injection Molding ◽  
Replication Process ◽  
Optical Elements ◽  
Process Step ◽  
Structured Surfaces ◽  
Laser Lithography

In recent years, the use of highly functional optical elements has made its way into our everyday life. Its applications range from use in utility items such as cell phone cameras up to security elements on banknotes or production goods. For this purpose, the Leibniz Institute for Materials Engineering (IWT) has been developing a cutting process for the fast and cost-effective production of hologram-based diffractive optical elements. In contrast to established non-mechanical manufacturing processes, such as laser lithography or chemical etching, which are able to produce optics in large quantities and with high accuracy, the diamond turning approach is extending these properties by offering several degrees of freedom. This allows for an almost unlimited geometric complexity and a structured area of considerable size (several tenth square millimeters), achieved in a single process step. In order to introduce diffractive security features to the mass market and to actual production goods, a high-performance replication process is required as the consecutive development step. Micro injection molding represents a feasible and promising option here. In particular, diamond machining enables the integration of safety features directly into the mold insert. Not only does this make additional assembly obsolete, but the safety feature can also be placed inconspicuously in the final product. In this paper, the potential of micro-injection molding as a replication process for diffractive structured surfaces will be investigated and demonstrated. Furthermore, the optical functionality after replication will be verified and evaluated.

Study on Micro-Feature of Backlight Module for Micro Injection Molding Technology

2007 ◽  
Vol 364-366 ◽  
pp. 53-57 ◽  
Author(s):  
Yung Kang Shen ◽  
Yi Lin ◽  
Jeou Long Lee ◽  
Fwu Hsing Liu ◽  
Chih Wei Wu ◽  
...  
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Mold Insert ◽  
Mold Temperature ◽  
Processing Parameters ◽  
High Viscosity ◽  
Injection Velocity ◽  
Parameter Method ◽  
Micro Injection Molding ◽  
Melt Temperature

This research first indicates the melt front delay of wedge-shaped lightguiding plate of backlight module on micro injection molding. This research fabricated the patterns of mold insert of lightguiding plate by photo etching process. The micro-facture of lightguiding plate was manufactured by micro injection molding. The lightguiding plate of backlight module was used for the PMMA material. The single parameter method was used to discuss the flatness and replication properties for different processing parameters (mold temperature, melt temperature, packing pressure, packing time and injection pressure). The results show that there are melt front delays due to the slow injection velocity, the low temperature induced by the little effect of shear heating, the high viscosity, the large flow resistance and the slow flow velocity. The mold temperature is the most important factor for the flatness and the replication of micro-feature of liughtguiding plate. Lower mold temperature induces better flatness properties. The surface roughness of micro-facture of lightguiding plate is 8.8 nm on micro injection molding for this work.

scholarly journals Micro Injection Molding of Thin Cavities Using Stereolithography for Mold Fabrication

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1848
Author(s):  
Rossella Surace ◽  
Vito Basile ◽  
Vincenzo Bellantone ◽  
Francesco Modica ◽  
Irene Fassi
Keyword(s):  
Injection Molding ◽  
Endurance Limit ◽  
Volume Ratio ◽  
Mold Insert ◽  
Great Accuracy ◽  
Micro Injection Molding ◽  
Small Series ◽  
Process Chains ◽  
Material Choice ◽  
Mold Fabrication

At the present time, there is a growing interest in additive manufacturing (AM) technologies and their integration into current process chains. In particular, the implementation of AM for tool production in micro injection molding (µ-IM), a well-established process, could introduce many advantages. First of all, AM could avoid the need for the time-consuming and expensive fabrication of molds for small series of customized products. In this work, the feasibility, quality, and reliability of an AM/µ-IM process chain were evaluated by designing and fabricating mold inserts for µ-IM by stereolithography (SLA) technology; the mold inserts were characterized and tested experimentally. The selected geometry is composed of four thin cavities: This particular feature represents an actual challenge for both the SLA and µ-IM perspective due to the large surface-to-volume ratio of the cavity. Two different materials were used for the mold fabrication, showing sharply different performance in terms of endurance limit and cavity degradation. The obtained results confirm that the µ-IM process, exploiting an SLA fabricated mold insert, is feasible but requires great accuracy in material choice, mold design, fabrication, and assembly.

scholarly journals An experimental study to investigate the micro-stereolithography tools for micro injection molding

2017 ◽  
Vol 23 (4) ◽  
pp. 711-719 ◽  
Author(s):  
Reza Gheisari ◽  
Paulo Bártolo ◽  
Nicholas Goddard ◽  
Marco Andre das Neves Domingos
Keyword(s):  
Injection Molding ◽  
Research Work ◽  
Thermal Characteristics ◽  
Micro Injection Molding ◽  
Tool Failure ◽  
Content Type ◽  
Rapid Injection ◽  
Short Run ◽  
Micro Features ◽  
Geometrical Dimensions

Purpose The use of microstereolithography (μSL) parts as micro-injection molding (μIM) tools greatly reduces the time and cost to product and offers unique solutions for complex design issues. However, they present challenges to designers because of their strength, thermal characteristics and shorter lifetimes as compared to other mold materials. The purpose of this study is to use SL to build rapid injection mold tools directly combining micro features for short-run production. Design/methodology/approach In total, three tool inserts were produced. Two different μSL mold inserts were produced and evaluated in terms of different build approaches of micro features. One of the inserts includes micro features built horizontally, while the other one collaborates features built vertically, both having same geometrical dimensions. To evaluate the replication capability of prototype tools, two different thicknesses were set for micro features, that is, 30 and 120 μm. The mold inserts were assembled on a metallic mold frame and tested with polypropylene (PP). Findings It was observed that using inappropriate resin to fabricate the mold inserts can lead to inaccurate geometrical dimensions of the tool. Therefore, the material with high glass transition temperature (Tg) and low thermal conductivity is preferred. Also, the results of this research work showed that the processed material and technology play an important role both on part quality and tool life. After investigating the tool failure mechanisms during the injection, it was observed that tool failure occurred mainly because of excessive flexural stresses and ejection forces during the cavity filling and part ejection phases, respectively. Originality/value The paper describes the capability of μSL mold inserts for the production of small batches of micro-cantilevers which are used in MEMS relays.

Plastic Micro Features Produced by Microwelding Machine

2011 ◽  
Vol 328-330 ◽  
pp. 1453-1456
Author(s):  
Hang Liu ◽  
Yan Xu ◽  
Kei Leung Yung ◽  
C.L. Kang ◽  
W. Tian
Keyword(s):  
Stainless Steel ◽  
Injection Molding ◽  
Polymer Melt ◽  
Micro Injection Molding ◽  
Micro Features

The method of using microwelding machine to fabricate micro features on a stainless steel micro mould has been studied. The micro features obtained from molding using an ultrasonic microwelding machine have shown distinctive characteristics. The microflow behavior of polymer melt during the microwelding process is also studied. The micro molds of 0.2mm thick and through holes of 0.05mm and 0.2mm in diameters were used. Results show micro features can be produced using the microwelding machine with molding speed comparable to that of micro injection molding.

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