Injection Molding Nano and Micro Pillar Arrays

2006 ◽  
Vol 326-328 ◽  
pp. 449-452
Author(s):  
Young Eun Yoo ◽  
Young Ho Seo ◽  
Seong Kon Kim ◽  
Tai Jin Je ◽  
Doo Sun Choi
Keyword(s):  
Injection Molding ◽  
Quartz Plate ◽  
The Other ◽  
Plastic Substrate ◽  
Nano Scale ◽  
Pillar Arrays ◽  
Injection Molded ◽  
Thin Plastic

An injection molding technology is developed to replicate pillars in micro/nano scale on the thin plastic substrate. Two types of pillar are to be replicated and one is square type of 10um x 10um, the other is circular type whose diameter is in range of 100 nm ~ 300 nm. For both types of the pillars, the height is about 250 nm. A pattern master is first fabricated on the photo resist(PR) layer spin coated to about 250nm of thickness on chrome/quartz plate by patterning e-beam writing and then developing the PR. The patterns on the PR master are transferred by nickel electro-plating to fabricate rigid nickel stamper. Using this nickel stamper, a substrate with nano pillars on its surface is injection molded by optimizing the conditions to fabricate DNA separating chip.

scholarly journals Are We Able to Print Components as Strong as Injection Molded?—Comparing the Properties of 3D Printed and Injection Molded Components Made from ABS Thermoplastic

2021 ◽  
Vol 11 (15) ◽  
pp. 6946
Author(s):  
Bartłomiej Podsiadły ◽  
Andrzej Skalski ◽  
Wiktor Rozpiórski ◽  
Marcin Słoma
Keyword(s):  
Tensile Strength ◽  
Injection Molding ◽  
Mechanical Strength ◽  
Cross Section ◽  
Fused Deposition Modeling ◽  
High Strength ◽  
Large Cross Section ◽  
Fused Deposition ◽  
Injection Molded ◽  
The Cross

In this paper, we are focusing on comparing results obtained for polymer elements manufactured with injection molding and additive manufacturing techniques. The analysis was performed for fused deposition modeling (FDM) and single screw injection molding with regards to the standards used in thermoplastics processing technology. We argue that the cross-section structure of the sample obtained via FDM is the key factor in the fabrication of high-strength components and that the dimensions of the samples have a strong influence on the mechanical properties. Large cross-section samples, 4 × 10 mm2, with three perimeter layers and 50% infill, have lower mechanical strength than injection molded reference samples—less than 60% of the strength. However, if we reduce the cross-section dimensions down to 2 × 4 mm2, the samples will be more durable, reaching up to 110% of the tensile strength observed for the injection molded samples. In the case of large cross-section samples, strength increases with the number of contour layers, leading to an increase of up to 97% of the tensile strength value for 11 perimeter layer samples. The mechanical strength of the printed components can also be improved by using lower values of the thickness of the deposited layers.

scholarly journals A Practical Numerical Approach to Characterizing Non-Linear Shrinkage and Optimizing Dimensional Deviation of Injection-Molded Small Module Plastic Gears

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2092
Author(s):  
Xiansong He ◽  
Wangqing Wu
Keyword(s):  
Injection Molding ◽  
High Speed ◽  
Numerical Approach ◽  
Linear Shrinkage ◽  
Influential Factor ◽  
Dimensional Deviation ◽  
Non Linear ◽  
Injection Molded ◽  
Plastic Gears ◽  
Circle Diameter

This paper was aimed at finding out the solution to the problem of insufficient dimensional accuracy caused by non-linear shrinkage deformation during injection molding of small module plastic gears. A practical numerical approach was proposed to characterize the non-linear shrinkage and optimize the dimensional deviation of the small module plastic gears. Specifically, Moldflow analysis was applied to visually simulate the shrinkage process of small module plastic gears during injection molding. A 3D shrinkage gear model was obtained and exported to compare with the designed gear model. After analyzing the non-linear shrinkage characteristics, the dimensional deviation of the addendum circle diameter and root circle diameter was investigated by orthogonal experiments. In the end, a high-speed cooling concept for the mold plate and the gear cavity was proposed to optimize the dimensional deviation. It was confirmed that the cooling rate is the most influential factor on the non-linear shrinkage of the injection-molded small module plastic gears. The dimensional deviation of the addendum circle diameter and the root circle diameter can be reduced by 22.79% and 22.99% with the proposed high-speed cooling concept, respectively.

scholarly journals Post-Processing Time Dependence of Shrinkage and Mechanical Properties of Injection-Molded Polypropylene

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 22
Author(s):  
Artur Kościuszko ◽  
Dawid Marciniak ◽  
Dariusz Sykutera
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Injection Molding ◽  
Accelerated Aging ◽  
Mold Temperature ◽  
Degree Of Crystallinity ◽  
Injection Mold ◽  
Secondary Crystallization ◽  
Scanning Calorimetry ◽  
Injection Molded

Dimensions of the injection-molded semi-crystalline materials (polymeric products) decrease with the time that elapses from their formation. The post-molding shrinkage is an effect of secondary crystallization; the increase in the degree of polymer crystallinity leads to an increase in stiffness and decrease in impact strength of the polymer material. The aim of this study was to assess the changes in the values of post-molding shrinkage of polypropylene produced by injection molding at two different temperatures of the mold (20 °C and 80 °C), and conditioned for 504 h at 23 °C. Subsequently, the samples were annealed for 24 h at 140 °C in order to conduct their accelerated aging. The results of shrinkage tests were related to the changes of mechanical properties that accompany the secondary crystallization. The degree of crystallinity of the conditioned samples was determined by means of density measurements and differential scanning calorimetry. It was found that the changes in the length of the moldings that took place after removal from the injection mold were accompanied by an increase of 20% in the modulus of elasticity, regardless of the conditions under which the samples were made. The differences in the shrinkage and mechanical properties of the samples resulting from mold temperature, as determined by tensile test, were removed by annealing. However, the samples made at two different injection mold temperature values still significantly differed in impact strength, the values of which were clearly higher for the annealed samples compared to the results determined for the samples immediately after the injection molding.

Mechanical Properties of Injection Molded Rubber Testing Samples

2015 ◽  
Vol 752-753 ◽  
pp. 308-311
Author(s):  
Adam Skrobak ◽  
Michal Stanek ◽  
David Manas ◽  
Martin Ovsik ◽  
Vojtech Senkerik ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Standardized Testing ◽  
Rubber Compound ◽  
Testing Sample ◽  
Synthetic Rubber ◽  
Injection Molded

The aim of this article is to demonstrate and asses to what extent there is an impact on the mechanical properties of a standardized testing sample made of rubber compound based on synthetic rubber EPDM and produced by injection molding in comparison with a sample produced by classic preparation (cutting off a compression molded plate) according to the standard ISO 23529.

scholarly journals Effects of Injection Molding Screw Tips on Polymer Mixing

2018 ◽  
Vol 62 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Dániel Török ◽  
József Gábor Kovács
Keyword(s):  
Injection Molding ◽  
Processing Parameters ◽  
Raw Material ◽  
Molding Machine ◽  
Surface Color ◽  
Melt Temperature ◽  
Injection Molding Machine ◽  
Aesthetic Appearance ◽  
Molded Parts ◽  
Injection Molded

In all fields of industry it is important to produce parts with good quality. Injection molded parts usually have to meet strict requirements technically and aesthetically. The aim of the measurements presented in our paper is to investigate the aesthetic appearance, such as surface color homogeneity, of injection molded parts. It depends on several factors, the raw material, the colorants, the injection molding machine and the processing parameters. In this project we investigated the effects of the injection molding machine on surface color homogeneity. We focused on injection molding screw tips and investigated five screw tips with different geometries. We produced flat specimens colored with a masterbatch and investigated color homogeneity. To evaluate the color homogeneity of the specimens, we used digital image analysis software developed by us. After that we measured the plastication rate and the melt temperature of the polymer melt because mixing depends on these factors. Our results showed that the screw tips (dynamic mixers) can improve surface color homogeneity but they cause an increase in melt temperature and a decrease in the plastication rate.

Measurement of Thermal Conductivity of a Flexible Substrate

2014 ◽  
Author(s):  
Vivek Vishwakarma ◽  
Ankur Jain
Keyword(s):  
Thermal Conductivity ◽  
Analytical Model ◽  
Flexible Substrate ◽  
Thermal Response ◽  
Experimental Methodology ◽  
Plastic Substrate ◽  
The Past ◽  
Thin Plastic ◽  
Transient Thermal ◽  
Transient Thermal Response

A number of past papers have described experimental techniques for measurement of thermal conductivity of substrates and thin films of technological interest. Nearly all substrates measured in the past are rigid. There is a lack of papers that report measurements on a flexible substrate such as thin plastic. The paper presents an experimental methodology to deposit a thin film microheater device on a plastic substrate. This device, comprising a microheater line and a temperature sensor line is used to measure the thermal conductivity of the plastic substrate using the transient thermal response of the plastic substrate to a heating current. An analytical model describing this thermal response is presented. Thermal conductivity of the plastic substrate is determined by comparison of experimental data with the analytical model. Results described in this paper may aid in development of an understanding of thermal transport in flexible substrates.

Observation and Evaluation of Scratch Damage Characteristics of Injection Molded, Rubber Toughened Poly(Methylmethacrylate)

2013 ◽  
Author(s):  
Jihun An ◽  
Byoung-Hyun Kang ◽  
Byoung-Ho Choi ◽  
Hyoung-Jun Kim
Keyword(s):  
Electron Microscopy ◽  
Injection Molding ◽  
Acrylonitrile Butadiene Styrene ◽  
Damage Mechanism ◽  
Damage Characteristics ◽  
Rubber Toughened ◽  
Rubber Particles ◽  
Injection Molded ◽  
Engineering Polymers ◽  
Scratch Tests

Poly(methylmethacrylate) (PMMA) is one of popular engineering polymers for many engineering applications such as glass substitutes, medical applications, electronic goods, optical fibers, laser disk optical media and so on. PMMA is a lightweight material with excellent optical properties and balanced mechanical properties. However, PMMA is commonly blended with various functional fillers, and rubber particles are one of them to improve the low impact toughness of unfilled PMMA comparing with other engineering polymers such as polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS) copolymer and so on. PMMA is generally used to make exterior of a commercial product, so scratch characteristics of PMMA is very important in terms of the aesthetic point of view. In this paper, rubber toughened PMMA plates are prepared by injection molding, and static and progressive scratch tests are performed. Samples are prepared by various injection molding conditions, and two orientations (machine direction and transverse direction) of the injection molded plate are considered for scratch tests. Three scratch damage mechanism stages, i.e. mar/ploughing, whitening and cutting stages, are identified by observing the scratch damages and two critical loads to define the variation of scratch damage mechanisms are recorded to evaluate the scratch resistance of rubber toughened PMMA samples. Scratch damage characteristics are examined by various microscopy techniques such as optical microscopy, scanning electron microscopy, transmission electron microscopy, atomic force microscopy, optical profiler and so on. It is clearly observed that scratch damage characteristics of rubber toughened PMMA are changed sensitively for various test conditions due to rubber particles, so it can be known that the mold design should be carefully optimized to improve scratch characteristics of injection molded rubber toughened PMMA product.

Microstructure, Hardness, and Wear Resistance of Powder-Injection-Molded Products of Fe-Based Metamorphic Powders

2007 ◽  
Vol 26-28 ◽  
pp. 355-358
Author(s):  
Chang Kyu Kim ◽  
Chang Young Son ◽  
Dae Jin Ha ◽  
Tae Sik Yoon ◽  
Sung Hak Lee
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Wear Resistance ◽  
Injection Molding ◽  
Powder Injection Molding ◽  
Powder Injection ◽  
Thermally Stable ◽  
Austenitic Matrix ◽  
Amorphous Phases ◽  
Injection Molded

Powder injection molding (PIM) process was applied to Fe-based metamorphic alloy powders, and microstructure, hardness, and wear resistance of the PIM products were analyzed and compared with those of conventional PIM stainless steel products. When Fe-based metamorphic powders were injection-molded and then sintered at 1200 oC, completely densified products with almost no pores were obtained. They contained 34 vol.% of (Cr,Fe)2B borides dispersed in the austenitic matrix without amorphous phases. Since these (Cr,Fe)2B borides were very hard and thermally stable, hardness, and wear resistance of the PIM products of Fe-based metamorphic powders were twice as high as those of conventional PIM stainless steel products. Such property improvement suggested new applicability of the PIM products of Fe-based metamorphic powders to structures and parts requiring excellent mechanical properties.

Mechanical Properties of Jute/PLA Injection Molded Products-All Natural Composites

2011 ◽  
Author(s):  
Masuo Murakami ◽  
Yuqiu Yang ◽  
Hiroyuki Hamada
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Density Measurement ◽  
The Other ◽  
Jute Fiber ◽  
Poly Lactic Acid ◽  
Thermoplastic Polymer ◽  
Environmental Friendly ◽  
Molding Condition ◽  
Natural Composites

Natural composites have been important materials system due to preservation of earth environments. Natural fibers such as jute, hemp, bagasse and so on are very good candidate of natural composites as reinforcements. On the other hand regarding matrix parts thermosetting polymer and thermoplastic polymer deriver form petrochemical products are not environmental friendly material, even if thermoplastic polymer can be recycled. In order to create fully environmental friendly material (FEFM) biodegradable polymer which can be deriver from natural resources is needed. Therefore poly(lactic acid) (PLA) polymer is very good material for the FEFM. However, PLA is very brittle polymer, so that polymer chemists have been made the efforts to make tough PLA. In this paper Jute/PLA composites was fabricated by injection moldings and mechanical properties were measured. It is believable that industries will have much attention to FEFM, so that injection molding was adopted to fabricate the composites. Long fiber pellet pultrusion technique was adopted to prepare jute fiber-PLA pellet (Jute/PLA). Because it is a new method which is able to fabricate composite pellets with relative long length fibers for injection molding process, where, jute yarns were continuously pulled and coated with PLA resin. Here two kinds of PLA materials were used including the one with mold releasing agent and the other is without it. After pass through a heated die whereby PLA resin impregnates into the jute yarns and sufficient cooling, the impregnated jute yarns were cut into pellets. Then Jute/PLA pellets were fed into injection machine to make dumbbell shape specimens. In current study, the effects of temperature of heat die i.e. impregnation temperature and the kind of PLA were focused to get optimum molding condition. The volume fractions of jute fiber in pellet were measured by several measuring method including image analyzing, density measurement and dissolution methods. And the mechanical property were investigated by tensile and Izod testing. It is found that 250 degree is much suitable for Jute/PLA long fiber pultrusion process. Additionally the jute fibers seem much effective to increase the tensile modulus and the Izod strength. That is to say, the addition of Jute fiber in PLA, the brittle property can be improved.

Direct Sinter Bonding of Metal Injection-Molded Parts to Solid Substrate Through Use of Deformable Surface Microfeatures

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Thomas Martens ◽  
M. Laine Mears
Keyword(s):  
Injection Molding ◽  
Solid Substrate ◽  
Metal Injection Molding ◽  
Full Density ◽  
Metal Powders ◽  
Molded Parts ◽  
Primary Obstacle ◽  
Injection Molded ◽  
Sinter Bonding ◽  
Micro Features

In the metal injection molding (MIM) process, fine metal powders are mixed with a binder and injected into molds, similar to plastic injection molding. After molding, the binder is removed from the part, and the compact is sintered to almost full density. Though able to create high-density parts of excellent dimensional control and surface finish, the MIM process is restricted in the size of part that can be produced, due to gravitational deformation during high-temperature sintering and maximum thickness requirements to remove the binding agents in the green state. Larger parts could be made by bonding the green parts to a substrate during sintering; however, a primary obstacle to this approach lies in the sinter shrinkage of the MIM part, which can be up to 20%, meaning that the MIM part shrinks during sintering, while the conventional substrate maintains its dimensions. This behavior would typically inhibit bonding and/or cause cracking and deformation of the MIM part. In this work, we present a structure of micro features molded onto the surface of the MIM part, which bonds, deforms, and allows for shrinkage while bonding to the substrate. The micro features tolerate plastic deformation to permit the shrinkage without causing cracks after the initial bonds are established. In a first series of tests, bond strengths of up to 80% of that of resistance welds have been achieved. This paper describes how the authors developed their proposed method of sinter bonding and how they accomplished effective sinter bonds between MIM parts and solid substrates.

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