Simulation of filling characteristics during hot embossing of polymer microstructures

Micro hot embossing process is a cost-effective method for parallel replication of polymer microstructures. To study the effect of hot embossing and demoulding parameters on the replication accuracy of the polymer microstructure, densely patterned and high-depth channels on 50mm×50mm polymer substrates were fabricated by hot embossing in this paper. Experimental results showed that the replication accuracy of the microstructure increased with the increasing of hot embossing temperature and the thickness of polymer substrates. It can be found that demoulding became more difficult when replication accuracy increased. The reason was that higher replication accuracy resulted in larger contact area between the replica and the embossing mold. The demoulding problem could be solved by rising demoulding temperature. However, overhigh demouding temperature (110°C) would lead to round corners at the edges of the ribs. Experimental results also showed that very small channel widths and depths errors (less than 1.2%) of the microstructures with 2mm thickness substrates could be achieved, when embossing and demoulding temperatures were set to 120°C and 100°C, respectively.

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Polymer Micro Hot Embossing with Bulk Metallic Glass Mold Insert

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.510.639 ◽

2012 ◽

Vol 510 ◽

pp. 639-644 ◽

Cited By ~ 4

Author(s):

Xiang Zhang ◽

Jiang Ma ◽

Ran Bai ◽

Qian Li ◽

Bing Li Sun ◽

...

Keyword(s):

Metallic Glass ◽

Bulk Metallic Glass ◽

Silicon Wafer ◽

Mold Insert ◽

Hot Embossing ◽

Glass Mold ◽

Mold Material ◽

Icp Etching ◽

Polymer Microstructures ◽

Micro Features

Polymer microstructures are used more and more in many fields. Hot embossing is one of molding processing to achieve micro polymer components. In this paper, bulk metallic glass was selected as mold material to fabricate mold insert of micro hot embossing. Traditional UV-lithography and ICP-etching were used to achieve micro features on silicon wafer. And then, micro features were transferred from silicon wafer to bulk metallic glass mold insert above its glass transition temperature. Finally, applied bulk metallic glass mold insert to replicate polymer microstructure with hot embossing. Three commonly used thermoplastic polymers: high-density polyethylene (HDPE), polypropylene (PP) and polycarbonate (PC) were selected in this study. Experiments show that microstructures can have a good replication from bulk metallic glass mold insert to the thermoplastic polymer using hot embossing.

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A Study on Formability of a Polyimide Film by Using Visco-Elasticity Measurement and Hot-Embossing Tests

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.1189 ◽

2007 ◽

Vol 561-565 ◽

pp. 1189-1192

Author(s):

Sung Won Youn ◽

Kazumi Suda ◽

Masaharu Takahashi ◽

Ryutaro Maeda

Keyword(s):

Shear Modulus ◽

Shear Viscosity ◽

Strong Dependence ◽

Polyimide Film ◽

Hot Embossing ◽

Dynamic Mechanical Properties ◽

Surface Appearance ◽

Different Temperatures ◽

Elasticity Measurement ◽

Filling Characteristics

This study explores the dynamic mechanical properties (e.g., storage shear modulus, loss tangent and shear viscosity) and formability of a polyimide film by visco-elasticity measurement and hot-embossing tests. The variations of storage shear modulus, tangent delta and the shear viscosity were measured as a function of the temperature for two frequencies. As a polyimide goes through its glass transition, it exhibits dramatic decreases in shear modulus and viscosity as well as the peak of tangent delta, and continues to show strong dependence on frequency and temperature. Moreover, the filling characteristics (e.g., surface appearance, replicated depth and surface roughness) of polyimide were investigated by hot-embossing tests at different temperatures using a mold with an aspect ratio of 2.5:1.

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